This document summarizes new features and bugfixes in each stable release
of Tor. If you want to see more detailed descriptions of the changes in
each development snapshot, see the ChangeLog file.

Changes in version 0.2.9.9 - 2017-01-23
  Tor 0.2.9.9 fixes a denial-of-service bug where an attacker could
  cause relays and clients to crash, even if they were not built with
  the --enable-expensive-hardening option. This bug affects all 0.2.9.x
  versions, and also affects 0.3.0.1-alpha: all relays running an affected
  version should upgrade.

  This release also resolves a client-side onion service reachability
  bug, and resolves a pair of small portability issues.

  o Major bugfixes (security):
    - Downgrade the "-ftrapv" option from "always on" to "only on when
      --enable-expensive-hardening is provided." This hardening option,
      like others, can turn survivable bugs into crashes -- and having
      it on by default made a (relatively harmless) integer overflow bug
      into a denial-of-service bug. Fixes bug 21278 (TROVE-2017-001);
      bugfix on 0.2.9.1-alpha.

  o Major bugfixes (client, onion service):
    - Fix a client-side onion service reachability bug, where multiple
      socks requests to an onion service (or a single slow request)
      could cause us to mistakenly mark some of the service's
      introduction points as failed, and we cache that failure so
      eventually we run out and can't reach the service. Also resolves a
      mysterious "Remote server sent bogus reason code 65021" log
      warning. The bug was introduced in ticket 17218, where we tried to
      remember the circuit end reason as a uint16_t, which mangled
      negative values. Partially fixes bug 21056 and fixes bug 20307;
      bugfix on 0.2.8.1-alpha.

  o Minor features (geoip):
    - Update geoip and geoip6 to the January 4 2017 Maxmind GeoLite2
      Country database.

  o Minor bugfixes (portability):
    - Avoid crashing when Tor is built using headers that contain
      CLOCK_MONOTONIC_COARSE, but then tries to run on an older kernel
      without CLOCK_MONOTONIC_COARSE. Fixes bug 21035; bugfix
      on 0.2.9.1-alpha.
    - Fix Libevent detection on platforms without Libevent 1 headers
      installed. Fixes bug 21051; bugfix on 0.2.9.1-alpha.


Changes in version 0.2.8.12 - 2016-12-19
  Tor 0.2.8.12 backports a fix for a medium-severity issue (bug 21018
  below) where Tor clients could crash when attempting to visit a
  hostile hidden service. Clients are recommended to upgrade as packages
  become available for their systems.

  It also includes an updated list of fallback directories, backported
  from 0.2.9.

  Now that the Tor 0.2.9 series is stable, only major bugfixes will be
  backported to 0.2.8 in the future.

  o Major bugfixes (parsing, security, backported from 0.2.9.8):
    - Fix a bug in parsing that could cause clients to read a single
      byte past the end of an allocated region. This bug could be used
      to cause hardened clients (built with --enable-expensive-hardening)
      to crash if they tried to visit a hostile hidden service. Non-
      hardened clients are only affected depending on the details of
      their platform's memory allocator. Fixes bug 21018; bugfix on
      0.2.0.8-alpha. Found by using libFuzzer. Also tracked as TROVE-
      2016-12-002 and as CVE-2016-1254.

  o Minor features (fallback directory list, backported from 0.2.9.8):
    - Replace the 81 remaining fallbacks of the 100 originally
      introduced in Tor 0.2.8.3-alpha in March 2016, with a list of 177
      fallbacks (123 new, 54 existing, 27 removed) generated in December
      2016. Resolves ticket 20170.

  o Minor features (geoip, backported from 0.2.9.7-rc):
    - Update geoip and geoip6 to the December 7 2016 Maxmind GeoLite2
      Country database.


Changes in version 0.2.9.8 - 2016-12-19
  Tor 0.2.9.8 is the first stable release of the Tor 0.2.9 series.

  The Tor 0.2.9 series makes mandatory a number of security features
  that were formerly optional. It includes support for a new shared-
  randomness protocol that will form the basis for next generation
  hidden services, includes a single-hop hidden service mode for
  optimizing .onion services that don't actually want to be hidden,
  tries harder not to overload the directory authorities with excessive
  downloads, and supports a better protocol versioning scheme for
  improved compatibility with other implementations of the Tor protocol.

  And of course, there are numerous other bugfixes and improvements.

  This release also includes a fix for a medium-severity issue (bug
  21018 below) where Tor clients could crash when attempting to visit a
  hostile hidden service. Clients are recommended to upgrade as packages
  become available for their systems.

  Below are listed the changes since Tor 0.2.8.11.  For a list of
  changes since 0.2.9.7-rc, see the ChangeLog file.

  o New system requirements:
    - When building with OpenSSL, Tor now requires version 1.0.1 or
      later. OpenSSL 1.0.0 and earlier are no longer supported by the
      OpenSSL team, and should not be used. Closes ticket 20303.
    - Tor now requires Libevent version 2.0.10-stable or later. Older
      versions of Libevent have less efficient backends for several
      platforms, and lack the DNS code that we use for our server-side
      DNS support. This implements ticket 19554.
    - Tor now requires zlib version 1.2 or later, for security,
      efficiency, and (eventually) gzip support. (Back when we started,
      zlib 1.1 and zlib 1.0 were still found in the wild. 1.2 was
      released in 2003. We recommend the latest version.)

  o Deprecated features:
    - A number of DNS-cache-related sub-options for client ports are now
      deprecated for security reasons, and may be removed in a future
      version of Tor. (We believe that client-side DNS caching is a bad
      idea for anonymity, and you should not turn it on.) The options
      are: CacheDNS, CacheIPv4DNS, CacheIPv6DNS, UseDNSCache,
      UseIPv4Cache, and UseIPv6Cache.
    - A number of options are deprecated for security reasons, and may
      be removed in a future version of Tor. The options are:
      AllowDotExit, AllowInvalidNodes, AllowSingleHopCircuits,
      AllowSingleHopExits, ClientDNSRejectInternalAddresses,
      CloseHSClientCircuitsImmediatelyOnTimeout,
      CloseHSServiceRendCircuitsImmediatelyOnTimeout,
      ExcludeSingleHopRelays, FastFirstHopPK, TLSECGroup,
      UseNTorHandshake, and WarnUnsafeSocks.
    - The *ListenAddress options are now deprecated as unnecessary: the
      corresponding *Port options should be used instead. These options
      may someday be removed. The affected options are:
      ControlListenAddress, DNSListenAddress, DirListenAddress,
      NATDListenAddress, ORListenAddress, SocksListenAddress,
      and TransListenAddress.

  o Major bugfixes (parsing, security, new since 0.2.9.7-rc):
    - Fix a bug in parsing that could cause clients to read a single
      byte past the end of an allocated region. This bug could be used
      to cause hardened clients (built with --enable-expensive-hardening)
      to crash if they tried to visit a hostile hidden service. Non-
      hardened clients are only affected depending on the details of
      their platform's memory allocator. Fixes bug 21018; bugfix on
      0.2.0.8-alpha. Found by using libFuzzer. Also tracked as TROVE-
      2016-12-002 and as CVE-2016-1254.

  o Major features (build, hardening):
    - Tor now builds with -ftrapv by default on compilers that support
      it. This option detects signed integer overflow (which C forbids),
      and turns it into a hard-failure. We do not apply this option to
      code that needs to run in constant time to avoid side-channels;
      instead, we use -fwrapv in that code. Closes ticket 17983.
    - When --enable-expensive-hardening is selected, stop applying the
      clang/gcc sanitizers to code that needs to run in constant time.
      Although we are aware of no introduced side-channels, we are not
      able to prove that there are none. Related to ticket 17983.

  o Major features (circuit building, security):
    - Authorities, relays, and clients now require ntor keys in all
      descriptors, for all hops (except for rare hidden service protocol
      cases), for all circuits, and for all other roles. Part of
      ticket 19163.
    - Authorities, relays, and clients only use ntor, except for
      rare cases in the hidden service protocol. Part of ticket 19163.

  o Major features (compilation):
    - Our big list of extra GCC warnings is now enabled by default when
      building with GCC (or with anything like Clang that claims to be
      GCC-compatible). To make all warnings into fatal compilation
      errors, pass --enable-fatal-warnings to configure. Closes
      ticket 19044.
    - Use the Autoconf macro AC_USE_SYSTEM_EXTENSIONS to automatically
      turn on C and POSIX extensions. (Previously, we attempted to do
      this on an ad hoc basis.) Closes ticket 19139.

  o Major features (directory authorities, hidden services):
    - Directory authorities can now perform the shared randomness
      protocol specified by proposal 250. Using this protocol, directory
      authorities generate a global fresh random value every day. In the
      future, this value will be used by hidden services to select
      HSDirs. This release implements the directory authority feature;
      the hidden service side will be implemented in the future as part
      of proposal 224. Resolves ticket 16943; implements proposal 250.

  o Major features (downloading, random exponential backoff):
    - When we fail to download an object from a directory service, wait
      for an (exponentially increasing) randomized amount of time before
      retrying, rather than a fixed interval as we did before. This
      prevents a group of Tor instances from becoming too synchronized,
      or a single Tor instance from becoming too predictable, in its
      download schedule. Closes ticket 15942.

  o Major features (resource management):
    - Tor can now notice it is about to run out of sockets, and
      preemptively close connections of lower priority. (This feature is
      off by default for now, since the current prioritizing method is
      yet not mature enough. You can enable it by setting
      "DisableOOSCheck 0", but watch out: it might close some sockets
      you would rather have it keep.) Closes ticket 18640.

  o Major features (single-hop "hidden" services):
    - Add experimental HiddenServiceSingleHopMode and
      HiddenServiceNonAnonymousMode options. When both are set to 1,
      every hidden service on that Tor instance becomes a non-anonymous
      Single Onion Service. Single Onions make one-hop (direct)
      connections to their introduction and rendezvous points. One-hop
      circuits make Single Onion servers easily locatable, but clients
      remain location-anonymous. This is compatible with the existing
      hidden service implementation, and works on the current Tor
      network without any changes to older relays or clients. Implements
      proposal 260, completes ticket 17178. Patch by teor and asn.

  o Major features (subprotocol versions):
    - Tor directory authorities now vote on a set of recommended
      "subprotocol versions", and on a set of required subprotocol
      versions. Clients and relays that lack support for a _required_
      subprotocol version will not start; those that lack support for a
      _recommended_ subprotocol version will warn the user to upgrade.
      This change allows compatible implementations of the Tor protocol(s)
      to exist without pretending to be 100% bug-compatible with
      particular releases of Tor itself. Closes ticket 19958; implements
      part of proposal 264.

  o Major bugfixes (circuit building):
    - Hidden service client-to-intro-point and service-to-rendezvous-
      point circuits use the TAP key supplied by the protocol, to avoid
      epistemic attacks. Fixes bug 19163; bugfix on 0.2.4.18-rc.

  o Major bugfixes (download scheduling):
    - Avoid resetting download status for consensuses hourly, since we
      already have another, smarter retry mechanism. Fixes bug 8625;
      bugfix on 0.2.0.9-alpha.
    - If a consensus expires while we are waiting for certificates to
      download, stop waiting for certificates.
    - If we stop waiting for certificates less than a minute after we
      started downloading them, do not consider the certificate download
      failure a separate failure. Fixes bug 20533; bugfix
      on 0.2.0.9-alpha.
    - When using exponential backoff in test networks, use a lower
      exponent, so the delays do not vary as much. This helps test
      networks bootstrap consistently. Fixes bug 20597; bugfix on 20499.

  o Major bugfixes (exit policies):
    - Avoid disclosing exit outbound bind addresses, configured port
      bind addresses, and local interface addresses in relay descriptors
      by default under ExitPolicyRejectPrivate. Instead, only reject
      these (otherwise unlisted) addresses if
      ExitPolicyRejectLocalInterfaces is set. Fixes bug 18456; bugfix on
      0.2.7.2-alpha. Patch by teor.

  o Major bugfixes (hidden services):
    - Allow Tor clients with appropriate controllers to work with
      FetchHidServDescriptors set to 0. Previously, this option also
      disabled descriptor cache lookup, thus breaking hidden services
      entirely. Fixes bug 18704; bugfix on 0.2.0.20-rc. Patch by "twim".
    - Clients now require hidden services to include the TAP keys for
      their intro points in the hidden service descriptor. This prevents
      an inadvertent upgrade to ntor, which a malicious hidden service
      could use to distinguish clients by consensus version. Fixes bug
      20012; bugfix on 0.2.4.8-alpha. Patch by teor.

  o Major bugfixes (relay, resolver, logging):
    - For relays that don't know their own address, avoid attempting a
      local hostname resolve for each descriptor we download. This
      will cut down on the number of "Success: chose address 'x.x.x.x'"
      log lines, and also avoid confusing clock jumps if the resolver
      is slow. Fixes bugs 20423 and 20610; bugfix on 0.2.8.1-alpha.

  o Minor features (port flags):
    - Add new flags to the *Port options to give finer control over which
      requests are allowed. The flags are NoDNSRequest, NoOnionTraffic,
      and the synthetic flag OnionTrafficOnly, which is equivalent to
      NoDNSRequest, NoIPv4Traffic, and NoIPv6Traffic. Closes enhancement
      18693; patch by "teor".

  o Minor features (build, hardening):
    - Detect and work around a libclang_rt problem that would prevent
      clang from finding __mulodi4() on some 32-bit platforms, and thus
      keep -ftrapv from linking on those systems. Closes ticket 19079.
    - When building on a system without runtime support for the runtime
      hardening options, try to log a useful warning at configuration
      time, rather than an incomprehensible warning at link time. If
      expensive hardening was requested, this warning becomes an error.
      Closes ticket 18895.

  o Minor features (client, directory):
    - Since authorities now omit all routers that lack the Running and
      Valid flags, we assume that any relay listed in the consensus must
      have those flags. Closes ticket 20001; implements part of
      proposal 272.

  o Minor features (code safety):
    - In our integer-parsing functions, ensure that the maximum value we
      allow is no smaller than the minimum value. Closes ticket 19063;
      patch from "U+039b".

  o Minor features (compilation, portability):
    - Compile correctly on MacOS 10.12 (aka "Sierra"). Closes
      ticket 20241.

  o Minor features (config):
    - Warn users when descriptor and port addresses are inconsistent.
      Mitigates bug 13953; patch by teor.

  o Minor features (controller):
    - Allow controllers to configure basic client authorization on
      hidden services when they create them with the ADD_ONION controller
      command. Implements ticket 15588. Patch by "special".
    - Fire a STATUS_SERVER controller event whenever the hibernation
      status changes between "awake"/"soft"/"hard". Closes ticket 18685.
    - Implement new GETINFO queries for all downloads that use
      download_status_t to schedule retries. This allows controllers to
      examine the schedule for pending downloads. Closes ticket 19323.

  o Minor features (development tools, etags):
    - Teach the "make tags" Makefile target how to correctly find
      "MOCK_IMPL" function definitions. Patch from nherring; closes
      ticket 16869.

  o Minor features (directory authority):
    - After voting, if the authorities decide that a relay is not
      "Valid", they no longer include it in the consensus at all. Closes
      ticket 20002; implements part of proposal 272.
    - Directory authorities now only give the Guard flag to a relay if
      they are also giving it the Stable flag. This change allows us to
      simplify path selection for clients. It should have minimal effect
      in practice, since >99% of Guards already have the Stable flag.
      Implements ticket 18624.
    - Directory authorities now write their v3-status-votes file out to
      disk earlier in the consensus process, so we have a record of the
      votes even if we abort the consensus process. Resolves
      ticket 19036.

  o Minor features (fallback directory list, new since 0.2.9.7-rc):
    - Replace the 81 remaining fallbacks of the 100 originally
      introduced in Tor 0.2.8.3-alpha in March 2016, with a list of 177
      fallbacks (123 new, 54 existing, 27 removed) generated in December
      2016. Resolves ticket 20170.

  o Minor features (hidden service):
    - Stop being so strict about the payload length of "rendezvous1"
      cells. We used to be locked in to the "TAP" handshake length, and
      now we can handle better handshakes like "ntor". Resolves
      ticket 18998.

  o Minor features (infrastructure, time):
    - Tor now includes an improved timer backend, so that we can
      efficiently support tens or hundreds of thousands of concurrent
      timers, as will be needed for some of our planned anti-traffic-
      analysis work. This code is based on William Ahern's "timeout.c"
      project, which implements a "tickless hierarchical timing wheel".
      Closes ticket 18365.
    - Tor now uses the operating system's monotonic timers (where
      available) for internal fine-grained timing. Previously we would
      look at the system clock, and then attempt to compensate for the
      clock running backwards. Closes ticket 18908.

  o Minor features (logging):
    - Add a set of macros to check nonfatal assertions, for internal
      use. Migrating more of our checks to these should help us avoid
      needless crash bugs. Closes ticket 18613.
    - Provide a more useful warning message when configured with an
      invalid Nickname. Closes ticket 18300; patch from "icanhasaccount".
    - When dumping unparseable router descriptors, optionally store them
      in separate files, named by digest, up to a configurable size
      limit. You can change the size limit by setting the
      MaxUnparseableDescSizeToLog option, and disable this feature by
      setting that option to 0. Closes ticket 18322.

  o Minor features (performance):
    - Change the "optimistic data" extension from "off by default" to
      "on by default". The default was ordinarily overridden by a
      consensus option, but when clients were bootstrapping for the
      first time, they would not have a consensus to get the option
      from. Changing this default saves a round-trip during startup.
      Closes ticket 18815.

  o Minor features (relay, usability):
    - When the directory authorities refuse a bad relay's descriptor,
      encourage the relay operator to contact us. Many relay operators
      won't notice this line in their logs, but it's a win if even a few
      learn why we don't like what their relay was doing. Resolves
      ticket 18760.

  o Minor features (security, TLS):
    - Servers no longer support clients that lack AES ciphersuites.
      (3DES is no longer considered an acceptable cipher.) We believe
      that no such Tor clients currently exist, since Tor has required
      OpenSSL 0.9.7 or later since 2009. Closes ticket 19998.

  o Minor features (testing):
    - Disable memory protections on OpenBSD when performing our unit
      tests for memwipe(). The test deliberately invokes undefined
      behavior, and the OpenBSD protections interfere with this. Patch
      from "rubiate". Closes ticket 20066.
    - Move the test-network.sh script to chutney, and modify tor's test-
      network.sh to call the (newer) chutney version when available.
      Resolves ticket 19116. Patch by teor.
    - Use the lcov convention for marking lines as unreachable, so that
      we don't count them when we're generating test coverage data.
      Update our coverage tools to understand this convention. Closes
      ticket 16792.
    - Our link-handshake unit tests now check that when invalid
      handshakes fail, they fail with the error messages we expected.
    - Our unit testing code that captures log messages no longer
      prevents them from being written out if the user asked for them
      (by passing --debug or --info or --notice or --warn to the "test"
      binary). This change prevents us from missing unexpected log
      messages simply because we were looking for others. Related to
      ticket 19999.
    - The unit tests now log all warning messages with the "BUG" flag.
      Previously, they only logged errors by default. This change will
      help us make our testing code more correct, and make sure that we
      only hit this code when we mean to. In the meantime, however,
      there will be more warnings in the unit test logs than before.
      This is preparatory work for ticket 19999.
    - The unit tests now treat any failure of a "tor_assert_nonfatal()"
      assertion as a test failure.
    - We've done significant work to make the unit tests run faster.

  o Minor features (testing, ipv6):
    - Add the hs-ipv6 chutney target to make test-network-all's IPv6
      tests. Remove bridges+hs, as it's somewhat redundant. This
      requires a recent chutney version that supports IPv6 clients,
      relays, and authorities. Closes ticket 20069; patch by teor.
    - Add the single-onion and single-onion-ipv6 chutney targets to
      "make test-network-all". This requires a recent chutney version
      with the single onion network flavors (git c72a652 or later).
      Closes ticket 20072; patch by teor.

  o Minor features (Tor2web):
    - Make Tor2web clients respect ReachableAddresses. This feature was
      inadvertently enabled in 0.2.8.6, then removed by bugfix 19973 on
      0.2.8.7. Implements feature 20034. Patch by teor.

  o Minor features (unix domain sockets):
    - When configuring a unix domain socket for a SocksPort,
      ControlPort, or Hidden service, you can now wrap the address in
      quotes, using C-style escapes inside the quotes. This allows unix
      domain socket paths to contain spaces. Resolves ticket 18753.

  o Minor features (user interface):
    - Tor now supports the ability to declare options deprecated, so
      that we can recommend that people stop using them. Previously, this
      was done in an ad-hoc way. There is a new --list-deprecated-options
      command-line option to list all of the deprecated options. Closes
      ticket 19820.

  o Minor features (virtual addresses):
    - Increase the maximum number of bits for the IPv6 virtual network
      prefix from 16 to 104. In this way, the condition for address
      allocation is less restrictive. Closes ticket 20151; feature
      on 0.2.4.7-alpha.

  o Minor bug fixes (circuits):
    - Use the CircuitBuildTimeout option whenever
      LearnCircuitBuildTimeout is disabled. Previously, we would respect
      the option when a user disabled it, but not when it was disabled
      because some other option was set. Fixes bug 20073; bugfix on
      0.2.4.12-alpha. Patch by teor.

  o Minor bugfixes (build):
    - The current Git revision when building from a local repository is
      now detected correctly when using git worktrees. Fixes bug 20492;
      bugfix on 0.2.3.9-alpha.

  o Minor bugfixes (relay address discovery):
    - Stop reordering IP addresses returned by the OS. This makes it
      more likely that Tor will guess the same relay IP address every
      time. Fixes issue 20163; bugfix on 0.2.7.1-alpha, ticket 17027.
      Reported by René Mayrhofer, patch by "cypherpunks".

  o Minor bugfixes (memory allocation):
    - Change how we allocate memory for large chunks on buffers, to
      avoid a (currently impossible) integer overflow, and to waste less
      space when allocating unusually large chunks. Fixes bug 20081;
      bugfix on 0.2.0.16-alpha. Issue identified by Guido Vranken.

  o Minor bugfixes (bootstrap):
    - Remember the directory server we fetched the consensus or previous
      certificates from, and use it to fetch future authority
      certificates. This change improves bootstrapping performance.
      Fixes bug 18963; bugfix on 0.2.8.1-alpha.

  o Minor bugfixes (circuits):
    - Make sure extend_info_from_router() is only called on servers.
      Fixes bug 19639; bugfix on 0.2.8.1-alpha.

  o Minor bugfixes (client, fascistfirewall):
    - Avoid spurious warnings when ReachableAddresses or FascistFirewall
      is set. Fixes bug 20306; bugfix on 0.2.8.2-alpha.

  o Minor bugfixes (client, unix domain sockets):
    - Disable IsolateClientAddr when using AF_UNIX backed SocksPorts as
      the client address is meaningless. Fixes bug 20261; bugfix
      on 0.2.6.3-alpha.

  o Minor bugfixes (code style):
    - Fix an integer signedness conversion issue in the case conversion
      tables. Fixes bug 19168; bugfix on 0.2.1.11-alpha.

  o Minor bugfixes (compilation):
    - Build correctly on versions of libevent2 without support for
      evutil_secure_rng_add_bytes(). Fixes bug 19904; bugfix
      on 0.2.5.4-alpha.
    - When building with Clang, use a full set of GCC warnings.
      (Previously, we included only a subset, because of the way we
      detected them.) Fixes bug 19216; bugfix on 0.2.0.1-alpha.
    - Detect Libevent2 functions correctly on systems that provide
      libevent2, but where libevent1 is linked with -levent. Fixes bug
      19904; bugfix on 0.2.2.24-alpha. Patch from Rubiate.
    - Run correctly when built on Windows build environments that
      require _vcsprintf(). Fixes bug 20560; bugfix on 0.2.2.11-alpha.

  o Minor bugfixes (configuration):
    - When parsing quoted configuration values from the torrc file,
      handle Windows line endings correctly. Fixes bug 19167; bugfix on
      0.2.0.16-alpha. Patch from "Pingl".

  o Minor bugfixes (directory authority):
    - Authorities now sort the "package" lines in their votes, for ease
      of debugging. (They are already sorted in consensus documents.)
      Fixes bug 18840; bugfix on 0.2.6.3-alpha.
    - Die with a more useful error when the operator forgets to place
      the authority_signing_key file into the keys directory. This
      avoids an uninformative assert & traceback about having an invalid
      key. Fixes bug 20065; bugfix on 0.2.0.1-alpha.
    - When allowing private addresses, mark Exits that only exit to
      private locations as such. Fixes bug 20064; bugfix
      on 0.2.2.9-alpha.
    - When parsing a detached signature, make sure we use the length of
      the digest algorithm instead of a hardcoded DIGEST256_LEN in
      order to avoid comparing bytes out-of-bounds with a smaller digest
      length such as SHA1. Fixes bug 19066; bugfix on 0.2.2.6-alpha.

  o Minor bugfixes (getpass):
    - Defensively fix a non-triggerable heap corruption at do_getpass()
      to protect ourselves from mistakes in the future. Fixes bug
      19223; bugfix on 0.2.7.3-rc. Bug found by Guido Vranken, patch
      by nherring.

  o Minor bugfixes (guard selection):
    - Don't mark guards as unreachable if connection_connect() fails.
      That function fails for local reasons, so it shouldn't reveal
      anything about the status of the guard. Fixes bug 14334; bugfix
      on 0.2.3.10-alpha.
    - Use a single entry guard even if the NumEntryGuards consensus
      parameter is not provided. Fixes bug 17688; bugfix
      on 0.2.5.6-alpha.

  o Minor bugfixes (hidden services):
    - Increase the minimum number of internal circuits we preemptively
      build from 2 to 3, so a circuit is available when a client
      connects to another onion service. Fixes bug 13239; bugfix
      on 0.1.0.1-rc.
    - Allow hidden services to run on IPv6 addresses even when the
      IPv6Exit option is not set. Fixes bug 18357; bugfix
      on 0.2.4.7-alpha.
    - Stop logging intro point details to the client log on certain
      error conditions. Fixed as part of bug 20012; bugfix on
      0.2.4.8-alpha. Patch by teor.
    - When deleting an ephemeral hidden service, close its intro points
      even if they are not completely open. Fixes bug 18604; bugfix
      on 0.2.7.1-alpha.
    - When configuring hidden services, check every hidden service
      directory's permissions. Previously, we only checked the last
      hidden service. Fixes bug 20529; bugfix on 0.2.6.2-alpha.

  o Minor bugfixes (IPv6, testing):
    - Check for IPv6 correctly on Linux when running test networks.
      Fixes bug 19905; bugfix on 0.2.7.3-rc; patch by teor.

  o Minor bugfixes (Linux seccomp2 sandbox):
    - Add permission to run the sched_yield() and sigaltstack() system
      calls, in order to support versions of Tor compiled with asan or
      ubsan code that use these calls. Now "sandbox 1" and
      "--enable-expensive-hardening" should be compatible on more
      systems. Fixes bug 20063; bugfix on 0.2.5.1-alpha.

  o Minor bugfixes (logging):
    - Downgrade a harmless log message about the
      pending_entry_connections list from "warn" to "info". Mitigates
      bug 19926.
    - Log a more accurate message when we fail to dump a microdescriptor.
      Fixes bug 17758; bugfix on 0.2.2.8-alpha. Patch from Daniel Pinto.
    - When logging a directory ownership mismatch, log the owning
      username correctly. Fixes bug 19578; bugfix on 0.2.2.29-beta.
    - When we are unable to remove the bw_accounting file, do not warn
      if the reason we couldn't remove it was that it didn't exist.
      Fixes bug 19964; bugfix on 0.2.5.4-alpha. Patch from pastly.

  o Minor bugfixes (memory leak):
    - Fix a series of slow memory leaks related to parsing torrc files
      and options. Fixes bug 19466; bugfix on 0.2.1.6-alpha.
    - Avoid a small memory leak when informing worker threads about
      rotated onion keys. Fixes bug 20401; bugfix on 0.2.6.3-alpha.
    - Fix a small memory leak when receiving AF_UNIX connections on a
      SocksPort. Fixes bug 20716; bugfix on 0.2.6.3-alpha.
    - When moving a signed descriptor object from a source to an
      existing destination, free the allocated memory inside that
      destination object. Fixes bug 20715; bugfix on 0.2.8.3-alpha.
    - Fix a memory leak and use-after-free error when removing entries
      from the sandbox's getaddrinfo() cache. Fixes bug 20710; bugfix on
      0.2.5.5-alpha. Patch from "cypherpunks".
    - Fix a small, uncommon memory leak that could occur when reading a
      truncated ed25519 key file. Fixes bug 18956; bugfix
      on 0.2.6.1-alpha.

  o Minor bugfixes (option parsing):
    - Count unix sockets when counting client listeners (SOCKS, Trans,
      NATD, and DNS). This has no user-visible behavior changes: these
      options are set once, and never read. Required for correct
      behavior in ticket 17178. Fixes bug 19677; bugfix on
      0.2.6.3-alpha. Patch by teor.

  o Minor bugfixes (options):
    - Check the consistency of UseEntryGuards and EntryNodes more
      reliably. Fixes bug 20074; bugfix on 0.2.4.12-alpha. Patch
      by teor.
    - Stop changing the configured value of UseEntryGuards on
      authorities and Tor2web clients. Fixes bug 20074; bugfix on
      commits 51fc6799 in 0.1.1.16-rc and acda1735 in 0.2.4.3-alpha.
      Patch by teor.

  o Minor bugfixes (relay):
    - Ensure relays don't make multiple connections during bootstrap.
      Fixes bug 20591; bugfix on 0.2.8.1-alpha.
    - Do not try to parallelize workers more than 16x without the user
      explicitly configuring us to do so, even if we do detect more than
      16 CPU cores. Fixes bug 19968; bugfix on 0.2.3.1-alpha.

  o Minor bugfixes (testing):
    - The test-stem and test-network makefile targets now depend only on
      the tor binary that they are testing. Previously, they depended on
      "make all". Fixes bug 18240; bugfix on 0.2.8.2-alpha. Based on a
      patch from "cypherpunks".
    - Allow clients to retry HSDirs much faster in test networks. Fixes
      bug 19702; bugfix on 0.2.7.1-alpha. Patch by teor.
    - Avoid a unit test failure on systems with over 16 detectable CPU
      cores. Fixes bug 19968; bugfix on 0.2.3.1-alpha.
    - Let backtrace tests work correctly under AddressSanitizer:
      disable ASAN's detection of segmentation faults while running
      test_bt.sh, so that we can make sure that our own backtrace
      generation code works. Fixes bug 18934; bugfix
      on 0.2.5.2-alpha. Patch from "cypherpunks".
    - Fix the test-network-all target on out-of-tree builds by using the
      correct path to the test driver script. Fixes bug 19421; bugfix
      on 0.2.7.3-rc.
    - Stop spurious failures in the local interface address discovery
      unit tests. Fixes bug 20634; bugfix on 0.2.8.1-alpha; patch by
      Neel Chauhan.
    - Use ECDHE ciphers instead of ECDH in tortls tests. LibreSSL has
      removed the ECDH ciphers which caused the tests to fail on
      platforms which use it. Fixes bug 20460; bugfix on 0.2.8.1-alpha.
    - The tor_tls_server_info_callback unit test no longer crashes when
      debug-level logging is turned on. Fixes bug 20041; bugfix
      on 0.2.8.1-alpha.

  o Minor bugfixes (time):
    - Improve overflow checks in tv_udiff and tv_mdiff. Fixes bug 19483;
      bugfix on all released tor versions.
    - When computing the difference between two times in milliseconds,
      we now round to the nearest millisecond correctly. Previously, we
      could sometimes round in the wrong direction. Fixes bug 19428;
      bugfix on 0.2.2.2-alpha.

  o Minor bugfixes (Tor2web):
    - Prevent Tor2web clients from running hidden services: these services
      are not anonymous due to the one-hop client paths. Fixes bug
      19678. Patch by teor.

  o Minor bugfixes (user interface):
    - Display a more accurate number of suppressed messages in the log
      rate-limiter. Previously, there was a potential integer overflow
      in the counter. Now, if the number of messages hits a maximum, the
      rate-limiter doesn't count any further. Fixes bug 19435; bugfix
      on 0.2.4.11-alpha.
    - Fix a typo in the passphrase prompt for the ed25519 identity key.
      Fixes bug 19503; bugfix on 0.2.7.2-alpha.

  o Code simplification and refactoring:
    - Remove redundant declarations of the MIN macro. Closes
      ticket 18889.
    - Rename tor_dup_addr() to tor_addr_to_str_dup() to avoid confusion.
      Closes ticket 18462; patch from "icanhasaccount".
    - Split the 600-line directory_handle_command_get function into
      separate functions for different URL types. Closes ticket 16698.

  o Documentation:
    - Add module-level internal documentation for 36 C files that
      previously didn't have a high-level overview. Closes ticket 20385.
    - Correct the IPv6 syntax in our documentation for the
      VirtualAddrNetworkIPv6 torrc option. Closes ticket 19743.
    - Correct the minimum bandwidth value in torrc.sample, and queue a
      corresponding change for torrc.minimal. Closes ticket 20085.
    - Fix spelling of "--enable-tor2web-mode" in the manpage. Closes
      ticket 19153. Patch from "U+039b".
    - Module-level documentation for several more modules. Closes
      tickets 19287 and 19290.
    - Document the --passphrase-fd option in the tor manpage. Fixes bug
      19504; bugfix on 0.2.7.3-rc.
    - Document the default PathsNeededToBuildCircuits value that's used
      by clients when the directory authorities don't set
      min_paths_for_circs_pct. Fixes bug 20117; bugfix on 0.2.4.10-alpha.
      Patch by teor, reported by Jesse V.
    - Fix manual for the User option: it takes a username, not a UID.
      Fixes bug 19122; bugfix on 0.0.2pre16 (the first version to have
      a manpage!).
    - Fix the description of the --passphrase-fd option in the
      tor-gencert manpage. The option is used to pass the number of a
      file descriptor to read the passphrase from, not to read the file
      descriptor from. Fixes bug 19505; bugfix on 0.2.0.20-alpha.

  o Removed code:
    - We no longer include the (dead, deprecated) bufferevent code in
      Tor. Closes ticket 19450. Based on a patch from "U+039b".

  o Removed features:
    - Remove support for "GET /tor/bytes.txt" DirPort request, and
      "GETINFO dir-usage" controller request, which were only available
      via a compile-time option in Tor anyway. Feature was added in
      0.2.2.1-alpha. Resolves ticket 19035.
    - There is no longer a compile-time option to disable support for
      TransPort. (If you don't want TransPort, just don't use it.) Patch
      from "U+039b". Closes ticket 19449.

  o Testing:
    - Run more workqueue tests as part of "make check". These had
      previously been implemented, but you needed to know special
      command-line options to enable them.
    - We now have unit tests for our code to reject zlib "compression
      bombs". (Fortunately, the code works fine.)


Changes in version 0.2.8.11 - 2016-12-08
  Tor 0.2.8.11 backports fixes for additional portability issues that
  could prevent Tor from building correctly on OSX Sierra, or with
  OpenSSL 1.1. Affected users should upgrade; others can safely stay
  with 0.2.8.10.

  o Minor bugfixes (portability):
    - Avoid compilation errors when building on OSX Sierra. Sierra began
      to support the getentropy() and clock_gettime() APIs, but created
      a few problems in doing so. Tor 0.2.9 has a more thorough set of
      workarounds; in 0.2.8, we are just using the /dev/urandom and mach
      monotonic time interfaces. Fixes bug 20865. Bugfix
      on 0.2.8.1-alpha.

  o Minor bugfixes (portability, backport from 0.2.9.5-alpha):
    - Fix compilation with OpenSSL 1.1 and less commonly-used CPU
      architectures. Closes ticket 20588.


Changes in version 0.2.8.10 - 2016-12-02
  Tor 0.2.8.10 backports a fix for a bug that would sometimes make clients
  unusable after they left standby mode. It also backports fixes for
  a few portability issues and a small but problematic memory leak.

  o Major bugfixes (client reliability, backport from 0.2.9.5-alpha):
    - When Tor leaves standby because of a new application request, open
      circuits as needed to serve that request. Previously, we would
      potentially wait a very long time. Fixes part of bug 19969; bugfix
      on 0.2.8.1-alpha.

  o Major bugfixes (client performance, backport from 0.2.9.5-alpha):
    - Clients now respond to new application stream requests immediately
      when they arrive, rather than waiting up to one second before
      starting to handle them. Fixes part of bug 19969; bugfix
      on 0.2.8.1-alpha.

  o Minor bugfixes (portability, backport from 0.2.9.6-rc):
    - Work around a bug in the OSX 10.12 SDK that would prevent us from
      successfully targeting earlier versions of OSX. Resolves
      ticket 20235.

  o Minor bugfixes (portability, backport from 0.2.9.5-alpha):
    - Fix implicit conversion warnings under OpenSSL 1.1. Fixes bug
      20551; bugfix on 0.2.1.1-alpha.

  o Minor bugfixes (relay, backport from 0.2.9.5-alpha):
    - Work around a memory leak in OpenSSL 1.1 when encoding public
      keys. Fixes bug 20553; bugfix on 0.0.2pre8.

  o Minor features (geoip):
    - Update geoip and geoip6 to the November 3 2016 Maxmind GeoLite2
      Country database.


Changes in version 0.2.8.9 - 2016-10-17
  Tor 0.2.8.9 backports a fix for a security hole in previous versions
  of Tor that would allow a remote attacker to crash a Tor client,
  hidden service, relay, or authority. All Tor users should upgrade to
  this version, or to 0.2.9.4-alpha. Patches will be released for older
  versions of Tor.

  o Major features (security fixes, also in 0.2.9.4-alpha):
    - Prevent a class of security bugs caused by treating the contents
      of a buffer chunk as if they were a NUL-terminated string. At
      least one such bug seems to be present in all currently used
      versions of Tor, and would allow an attacker to remotely crash
      most Tor instances, especially those compiled with extra compiler
      hardening. With this defense in place, such bugs can't crash Tor,
      though we should still fix them as they occur. Closes ticket
      20384 (TROVE-2016-10-001).

  o Minor features (geoip):
    - Update geoip and geoip6 to the October 4 2016 Maxmind GeoLite2
      Country database.


Changes in version 0.2.8.8 - 2016-09-23
  Tor 0.2.8.8 fixes two crash bugs present in previous versions of the
  0.2.8.x series. Relays running 0.2.8.x should upgrade, as should users
  who select public relays as their bridges.

  o Major bugfixes (crash):
    - Fix a complicated crash bug that could affect Tor clients
      configured to use bridges when replacing a networkstatus consensus
      in which one of their bridges was mentioned. OpenBSD users saw
      more crashes here, but all platforms were potentially affected.
      Fixes bug 20103; bugfix on 0.2.8.2-alpha.

  o Major bugfixes (relay, OOM handler):
    - Fix a timing-dependent assertion failure that could occur when we
      tried to flush from a circuit after having freed its cells because
      of an out-of-memory condition. Fixes bug 20203; bugfix on
      0.2.8.1-alpha. Thanks to "cypherpunks" for help diagnosing
      this one.

  o Minor feature (fallback directories):
    - Remove broken fallbacks from the hard-coded fallback directory
      list. Closes ticket 20190; patch by teor.

  o Minor features (geoip):
    - Update geoip and geoip6 to the September 6 2016 Maxmind GeoLite2
      Country database.


Changes in version 0.2.8.7 - 2016-08-24
  Tor 0.2.8.7 fixes an important bug related to the ReachableAddresses
  option in 0.2.8.6, and replaces a retiring bridge authority. Everyone
  who sets the ReachableAddresses option, and all bridges, are strongly
  encouraged to upgrade.

  o Directory authority changes:
    - The "Tonga" bridge authority has been retired; the new bridge
      authority is "Bifroest". Closes tickets 19728 and 19690.

  o Major bugfixes (client, security):
    - Only use the ReachableAddresses option to restrict the first hop
      in a path. In earlier versions of 0.2.8.x, it would apply to
      every hop in the path, with a possible degradation in anonymity
      for anyone using an uncommon ReachableAddress setting. Fixes bug
      19973; bugfix on 0.2.8.2-alpha.

  o Minor features (geoip):
    - Update geoip and geoip6 to the August 2 2016 Maxmind GeoLite2
      Country database.

  o Minor bugfixes (compilation):
    - Remove an inappropriate "inline" in tortls.c that was causing
      warnings on older versions of GCC. Fixes bug 19903; bugfix
      on 0.2.8.1-alpha.

  o Minor bugfixes (fallback directories):
    - Avoid logging a NULL string pointer when loading fallback
      directory information. Fixes bug 19947; bugfix on 0.2.4.7-alpha
      and 0.2.8.1-alpha. Report and patch by "rubiate".


Changes in version 0.2.8.6 - 2016-08-02

  Tor 0.2.8.6 is the first stable version of the Tor 0.2.8 series.

  The Tor 0.2.8 series improves client bootstrapping performance,
  completes the authority-side implementation of improved identity
  keys for relays, and includes numerous bugfixes and performance
  improvements throughout the program. This release continues to
  improve the coverage of Tor's test suite.  For a full list of
  changes since Tor 0.2.7, see the ReleaseNotes file.

  Below is a list of the changes since Tor 0.2.7.

  o New system requirements:
    - Tor no longer attempts to support platforms where the "time_t"
      type is unsigned. (To the best of our knowledge, only OpenVMS does
      this, and Tor has never actually built on OpenVMS.) Closes
      ticket 18184.
    - Tor no longer supports versions of OpenSSL with a broken
      implementation of counter mode. (This bug was present in OpenSSL
      1.0.0, and was fixed in OpenSSL 1.0.0a.) Tor still detects, but no
      longer runs with, these versions.
    - Tor now uses Autoconf version 2.63 or later, and Automake 1.11 or
      later (released in 2008 and 2009 respectively). If you are
      building Tor from the git repository instead of from the source
      distribution, and your tools are older than this, you will need to
      upgrade. Closes ticket 17732.

  o Directory authority changes:
    - Update the V3 identity key for the dannenberg directory authority:
      it was changed on 18 November 2015. Closes task 17906. Patch
      by teor.
    - Urras is no longer a directory authority. Closes ticket 19271.

  o Major features (directory system):
    - Include a trial list of default fallback directories, based on an
      opt-in survey of suitable relays. Doing this should make clients
      bootstrap more quickly and reliably, and reduce the load on the
      directory authorities. Closes ticket 15775. Patch by teor.
      Candidates identified using an OnionOO script by weasel, teor,
      gsathya, and karsten.
    - Previously only relays that explicitly opened a directory port
      (DirPort) accepted directory requests from clients. Now all
      relays, with and without a DirPort, accept and serve tunneled
      directory requests that they receive through their ORPort. You can
      disable this behavior using the new DirCache option. Closes
      ticket 12538.
    - When bootstrapping multiple consensus downloads at a time, use the
      first one that starts downloading, and close the rest. This
      reduces failures when authorities or fallback directories are slow
      or down. Together with the code for feature 15775, this feature
      should reduces failures due to fallback churn. Implements ticket
      4483. Patch by teor. Implements IPv4 portions of proposal 210 by
      mikeperry and teor.

  o Major features (security, Linux):
    - When Tor starts as root on Linux and is told to switch user ID, it
      can now retain the capability to bind to low ports. By default,
      Tor will do this only when it's switching user ID and some low
      ports have been configured. You can change this behavior with the
      new option KeepBindCapabilities. Closes ticket 8195.

  o Major bugfixes (client, bootstrapping):
    - Check if bootstrap consensus downloads are still needed when the
      linked connection attaches. This prevents tor making unnecessary
      begindir-style connections, which are the only directory
      connections tor clients make since the fix for 18483 was merged.
    - Fix some edge cases where consensus download connections may not
      have been closed, even though they were not needed. Related to fix
      for 18809.
    - Make relays retry consensus downloads the correct number of times,
      rather than the more aggressive client retry count. Fixes part of
      ticket 18809.

  o Major bugfixes (dns proxy mode, crash):
    - Avoid crashing when running as a DNS proxy. Fixes bug 16248;
      bugfix on 0.2.0.1-alpha. Patch from "cypherpunks".

  o Major bugfixes (ed25519, voting):
    - Actually enable support for authorities to match routers by their
      Ed25519 identities. Previously, the code had been written, but
      some debugging code that had accidentally been left in the
      codebase made it stay turned off. Fixes bug 17702; bugfix
      on 0.2.7.2-alpha.
    - When collating votes by Ed25519 identities, authorities now
      include a "NoEdConsensus" flag if the ed25519 value (or lack
      thereof) for a server does not reflect the majority consensus.
      Related to bug 17668; bugfix on 0.2.7.2-alpha.
    - When generating a vote with keypinning disabled, never include two
      entries for the same ed25519 identity. This bug was causing
      authorities to generate votes that they could not parse when a
      router violated key pinning by changing its RSA identity but
      keeping its Ed25519 identity. Fixes bug 17668; fixes part of bug
      18318. Bugfix on 0.2.7.2-alpha.

  o Major bugfixes (key management):
    - If OpenSSL fails to generate an RSA key, do not retain a dangling
      pointer to the previous (uninitialized) key value. The impact here
      should be limited to a difficult-to-trigger crash, if OpenSSL is
      running an engine that makes key generation failures possible, or
      if OpenSSL runs out of memory. Fixes bug 19152; bugfix on
      0.2.1.10-alpha. Found by Yuan Jochen Kang, Suman Jana, and
      Baishakhi Ray.

  o Major bugfixes (security, client, DNS proxy):
    - Stop a crash that could occur when a client running with DNSPort
      received a query with multiple address types, and the first
      address type was not supported. Found and fixed by Scott Dial.
      Fixes bug 18710; bugfix on 0.2.5.4-alpha.

  o Major bugfixes (security, compilation):
    - Correctly detect compiler flags on systems where _FORTIFY_SOURCE
      is predefined. Previously, our use of -D_FORTIFY_SOURCE would
      cause a compiler warning, thereby making other checks fail, and
      needlessly disabling compiler-hardening support. Fixes one case of
      bug 18841; bugfix on 0.2.3.17-beta. Patch from "trudokal".
    - Repair hardened builds under the clang compiler. Previously, our
      use of _FORTIFY_SOURCE would conflict with clang's address
      sanitizer. Fixes bug 14821; bugfix on 0.2.5.4-alpha.

  o Major bugfixes (security, pointers):
    - Avoid a difficult-to-trigger heap corruption attack when extending
      a smartlist to contain over 16GB of pointers. Fixes bug 18162;
      bugfix on 0.1.1.11-alpha, which fixed a related bug incompletely.
      Reported by Guido Vranken.

  o Major bugfixes (testing):
    - Fix a bug that would block 'make test-network-all' on systems where
      IPv6 packets were lost. Fixes bug 19008; bugfix on 0.2.7.3-rc.

  o Major bugfixes (user interface):
    - Correctly give a warning in the cases where a relay is specified
      by nickname, and one such relay is found, but it is not officially
      Named. Fixes bug 19203; bugfix on 0.2.3.1-alpha.

  o Minor features (accounting):
    - Added two modes to the AccountingRule option: One for limiting
      only the number of bytes sent ("AccountingRule out"), and one for
      limiting only the number of bytes received ("AccountingRule in").
      Closes ticket 15989; patch from "unixninja92".

  o Minor features (bug-resistance):
    - Make Tor survive errors involving connections without a
      corresponding event object. Previously we'd fail with an
      assertion; now we produce a log message. Related to bug 16248.
    - Use tor_snprintf() and tor_vsnprintf() even in external and low-
      level code, to harden against accidental failures to NUL-
      terminate. Part of ticket 17852. Patch from jsturgix. Found
      with Flawfinder.

  o Minor features (build):
    - Detect systems with FreeBSD-derived kernels (such as GNU/kFreeBSD)
      as having possible IPFW support. Closes ticket 18448. Patch from
      Steven Chamberlain.
    - Since our build process now uses "make distcheck", we no longer
      force "make dist" to depend on "make check". Closes ticket 17893;
      patch from "cypherpunks".
    - Tor now builds once again with the recent OpenSSL 1.1 development
      branch (tested against 1.1.0-pre5 and 1.1.0-pre6-dev). We have been
      tracking OpenSSL 1.1 development as it has progressed, and fixing
      numerous compatibility issues as they arose. See tickets
      17549, 17921, 17984, 19499, and 18286.
    - When building manual pages, set the timezone to "UTC", so that the
      output is reproducible. Fixes bug 19558; bugfix on 0.2.2.9-alpha.
      Patch from intrigeri.

  o Minor features (clients):
    - Make clients, onion services, and bridge relays always use an
      encrypted begindir connection for directory requests. Resolves
      ticket 18483. Patch by teor.

  o Minor features (controller):
    - Add 'GETINFO exit-policy/reject-private/[default,relay]', so
      controllers can examine the the reject rules added by
      ExitPolicyRejectPrivate. This makes it easier for stem to display
      exit policies.
    - Adds the FallbackDir entries to 'GETINFO config/defaults'. Closes
      tickets 16774 and 17817. Patch by George Tankersley.
    - New 'GETINFO hs/service/desc/id/' command to retrieve a hidden
      service descriptor from a service's local hidden service
      descriptor cache. Closes ticket 14846.

  o Minor features (crypto):
    - Add SHA3 and SHAKE support to crypto.c. Closes ticket 17783.
    - Add SHA512 support to crypto.c. Closes ticket 17663; patch from
      George Tankersley.
    - Improve performance when hashing non-multiple of 8 sized buffers,
      based on Andrew Moon's public domain SipHash-2-4 implementation.
      Fixes bug 17544; bugfix on 0.2.5.3-alpha.
    - Validate the hard-coded Diffie-Hellman parameters and ensure that
      p is a safe prime, and g is a suitable generator. Closes
      ticket 18221.
    - When allocating a digest state object, allocate no more space than
      we actually need. Previously, we would allocate as much space as
      the state for the largest algorithm would need. This change saves
      up to 672 bytes per circuit. Closes ticket 17796.

  o Minor features (directory downloads):
    - Add UseDefaultFallbackDirs, which enables any hard-coded fallback
      directory mirrors. The default is 1; set it to 0 to disable
      fallbacks. Implements ticket 17576. Patch by teor.
    - Wait for busy authorities and fallback directories to become non-
      busy when bootstrapping. (A similar change was made in 6c443e987d
      for directory caches chosen from the consensus.) Closes ticket
      17864; patch by teor.

  o Minor features (geoip):
    - Update geoip and geoip6 to the July 6 2016 Maxmind GeoLite2
      Country database.

  o Minor features (hidden service directory):
    - Streamline relay-side hsdir handling: when relays consider whether
      to accept an uploaded hidden service descriptor, they no longer
      check whether they are one of the relays in the network that is
      "supposed" to handle that descriptor. Implements ticket 18332.

  o Minor features (IPv6):
    - Add ClientPreferIPv6DirPort, which is set to 0 by default. If set
      to 1, tor prefers IPv6 directory addresses.
    - Add ClientUseIPv4, which is set to 1 by default. If set to 0, tor
      avoids using IPv4 for client OR and directory connections.
    - Add address policy assume_action support for IPv6 addresses.
    - Add an argument 'ipv6=address:orport' to the DirAuthority and
      FallbackDir torrc options, to specify an IPv6 address for an
      authority or fallback directory. Add hard-coded ipv6 addresses for
      directory authorities that have them. Closes ticket 17327; patch
      from Nick Mathewson and teor.
    - Allow users to configure directory authorities and fallback
      directory servers with IPv6 addresses and ORPorts. Resolves
      ticket 6027.
    - Limit IPv6 mask bits to 128.
    - Make tor_ersatz_socketpair work on IPv6-only systems. Fixes bug
      17638; bugfix on 0.0.2pre8. Patch by teor.
    - Try harder to obey the IP version restrictions "ClientUseIPv4 0",
      "ClientUseIPv6 0", "ClientPreferIPv6ORPort", and
      "ClientPreferIPv6DirPort". Closes ticket 17840; patch by teor.
    - Warn when comparing against an AF_UNSPEC address in a policy, it's
      almost always a bug. Closes ticket 17863; patch by teor.
    - routerset_parse now accepts IPv6 literal addresses. Fixes bug
      17060; bugfix on 0.2.1.3-alpha. Patch by teor.

  o Minor features (Linux seccomp2 sandbox):
    - Reject attempts to change our Address with "Sandbox 1" enabled.
      Changing Address with Sandbox turned on would never actually work,
      but previously it would fail in strange and confusing ways. Found
      while fixing 18548.

  o Minor features (logging):
    - When logging to syslog, allow a tag to be added to the syslog
      identity (the string prepended to every log message). The tag can
      be configured with SyslogIdentityTag and defaults to none. Setting
      it to "foo" will cause logs to be tagged as "Tor-foo". Closes
      ticket 17194.

  o Minor features (portability):
    - Use timingsafe_memcmp() where available. Closes ticket 17944;
      patch from <logan@hackers.mu>.

  o Minor features (relay, address discovery):
    - Add a family argument to get_interface_addresses_raw() and
      subfunctions to make network interface address interogation more
      efficient. Now Tor can specifically ask for IPv4, IPv6 or both
      types of interfaces from the operating system. Resolves
      ticket 17950.
    - When get_interface_address6_list(.,AF_UNSPEC,.) is called and
      fails to enumerate interface addresses using the platform-specific
      API, have it rely on the UDP socket fallback technique to try and
      find out what IP addresses (both IPv4 and IPv6) our machine has.
      Resolves ticket 17951.

  o Minor features (replay cache):
    - The replay cache now uses SHA256 instead of SHA1. Implements
      feature 8961. Patch by teor, issue reported by rransom.

  o Minor features (robustness):
    - Exit immediately with an error message if the code attempts to use
      Libevent without having initialized it. This should resolve some
      frequently-made mistakes in our unit tests. Closes ticket 18241.

  o Minor features (security, clock):
    - Warn when the system clock appears to move back in time (when the
      state file was last written in the future). Tor doesn't know that
      consensuses have expired if the clock is in the past. Patch by
      teor. Implements ticket 17188.

  o Minor features (security, exit policies):
    - ExitPolicyRejectPrivate now rejects more private addresses by
      default. Specifically, it now rejects the relay's outbound bind
      addresses (if configured), and the relay's configured port
      addresses (such as ORPort and DirPort). Fixes bug 17027; bugfix on
      0.2.0.11-alpha. Patch by teor.

  o Minor features (security, memory erasure):
    - Make memwipe() do nothing when passed a NULL pointer or buffer of
      zero size. Check size argument to memwipe() for underflow. Fixes
      bug 18089; bugfix on 0.2.3.25 and 0.2.4.6-alpha. Reported by "gk",
      patch by teor.
    - Set the unused entries in a smartlist to NULL. This helped catch
      a (harmless) bug, and shouldn't affect performance too much.
      Implements ticket 17026.
    - Use SecureMemoryWipe() function to securely clean memory on
      Windows. Previously we'd use OpenSSL's OPENSSL_cleanse() function.
      Implements feature 17986.
    - Use explicit_bzero or memset_s when present. Previously, we'd use
      OpenSSL's OPENSSL_cleanse() function. Closes ticket 7419; patches
      from <logan@hackers.mu> and <selven@hackers.mu>.

  o Minor features (security, RNG):
    - Adjust Tor's use of OpenSSL's RNG APIs so that they absolutely,
      positively are not allowed to fail. Previously we depended on
      internal details of OpenSSL's behavior. Closes ticket 17686.
    - Never use the system entropy output directly for anything besides
      seeding the PRNG. When we want to generate important keys, instead
      of using system entropy directly, we now hash it with the PRNG
      stream. This may help resist certain attacks based on broken OS
      entropy implementations. Closes part of ticket 17694.
    - Use modern system calls (like getentropy() or getrandom()) to
      generate strong entropy on platforms that have them. Closes
      ticket 13696.

  o Minor features (security, win32):
    - Set SO_EXCLUSIVEADDRUSE on Win32 to avoid a local port-stealing
      attack. Fixes bug 18123; bugfix on all tor versions. Patch
      by teor.

  o Minor features (unix domain sockets):
    - Add a new per-socket option, RelaxDirModeCheck, to allow creating
      Unix domain sockets without checking the permissions on the parent
      directory. (Tor checks permissions by default because some
      operating systems only check permissions on the parent directory.
      However, some operating systems do look at permissions on the
      socket, and tor's default check is unneeded.) Closes ticket 18458.
      Patch by weasel.

  o Minor features (unix file permissions):
    - Defer creation of Unix sockets until after setuid. This avoids
      needing CAP_CHOWN and CAP_FOWNER when using systemd's
      CapabilityBoundingSet, or chown and fowner when using SELinux.
      Implements part of ticket 17562. Patch from Jamie Nguyen.
    - If any directory created by Tor is marked as group readable, the
      filesystem group is allowed to be either the default GID or the
      root user. Allowing root to read the DataDirectory prevents the
      need for CAP_READ_SEARCH when using systemd's
      CapabilityBoundingSet, or dac_read_search when using SELinux.
      Implements part of ticket 17562. Patch from Jamie Nguyen.
    - Introduce a new DataDirectoryGroupReadable option. If it is set to
      1, the DataDirectory will be made readable by the default GID.
      Implements part of ticket 17562. Patch from Jamie Nguyen.

  o Minor bugfixes (accounting):
    - The max bandwidth when using 'AccountRule sum' is now correctly
      logged. Fixes bug 18024; bugfix on 0.2.6.1-alpha. Patch
      from "unixninja92".

  o Minor bugfixes (assert, portability):
    - Fix an assertion failure in memarea.c on systems where "long" is
      shorter than the size of a pointer. Fixes bug 18716; bugfix
      on 0.2.1.1-alpha.

  o Minor bugfixes (bootstrap):
    - Consistently use the consensus download schedule for authority
      certificates. Fixes bug 18816; bugfix on 0.2.4.13-alpha.

  o Minor bugfixes (build):
    - Avoid spurious failures from configure files related to calling
      exit(0) in TOR_SEARCH_LIBRARY. Fixes bug 18626; bugfix on
      0.2.0.1-alpha. Patch from "cypherpunks".
    - Do not link the unit tests against both the testing and non-
      testing versions of the static libraries. Fixes bug 18490; bugfix
      on 0.2.7.1-alpha.
    - Resolve warnings when building on systems that are concerned with
      signed char. Fixes bug 18728; bugfix on 0.2.7.2-alpha
      and 0.2.6.1-alpha.
    - Silence spurious clang-scan warnings in the ed25519_donna code by
      explicitly initializing some objects. Fixes bug 18384; bugfix on
      0.2.7.2-alpha. Patch by teor.
    - When libscrypt.h is found, but no libscrypt library can be linked,
      treat libscrypt as absent. Fixes bug 19161; bugfix
      on 0.2.6.1-alpha.
    - Cause the unit tests to compile correctly on mingw64 versions that
      lack sscanf. Fixes bug 19213; bugfix on 0.2.7.1-alpha.
    - Don't try to use the pthread_condattr_setclock() function unless
      it actually exists. Fixes compilation on NetBSD-6.x. Fixes bug
      17819; bugfix on 0.2.6.3-alpha.
    - Fix backtrace compilation on FreeBSD. Fixes bug 17827; bugfix
      on 0.2.5.2-alpha.
    - Fix search for libevent libraries on OpenBSD (and other systems
      that install libevent 1 and libevent 2 in parallel). Fixes bug
      16651; bugfix on 0.1.0.7-rc. Patch from "rubiate".
    - Isolate environment variables meant for tests from the rest of the
      build system. Fixes bug 17818; bugfix on 0.2.7.3-rc.
    - Mark all object files that include micro-revision.i as depending
      on it, so as to make parallel builds more reliable. Fixes bug
      17826; bugfix on 0.2.5.1-alpha.
    - Remove config.log only from make distclean, not from make clean.
      Fixes bug 17924; bugfix on 0.2.4.1-alpha.
    - Replace usage of 'INLINE' with 'inline'. Fixes bug 17804; bugfix
      on 0.0.2pre8.
    - Remove an #endif from configure.ac so that we correctly detect the
      presence of in6_addr.s6_addr32. Fixes bug 17923; bugfix
      on 0.2.0.13-alpha.

  o Minor bugfixes (client, bootstrap):
    - Count receipt of new microdescriptors as progress towards
      bootstrapping. Previously, with EntryNodes set, Tor might not
      successfully repopulate the guard set on bootstrapping. Fixes bug
      16825; bugfix on 0.2.3.1-alpha.

  o Minor bugfixes (code correctness):
    - Fix a bad memory handling bug that would occur if we had queued a
      cell on a channel's incoming queue. Fortunately, we can't actually
      queue a cell like that as our code is constructed today, but it's
      best to avoid this kind of error, even if there isn't any code
      that triggers it today. Fixes bug 18570; bugfix on 0.2.4.4-alpha.
    - Assert that allocated memory held by the reputation code is freed
      according to its internal counters. Fixes bug 17753; bugfix
      on 0.1.1.1-alpha.
    - Assert when the TLS contexts fail to initialize. Fixes bug 17683;
      bugfix on 0.0.6.
    - Update to the latest version of Trunnel, which tries harder to
      avoid generating code that can invoke memcpy(p,NULL,0). Bug found
      by clang address sanitizer. Fixes bug 18373; bugfix
      on 0.2.7.2-alpha.
    - When closing an entry connection, generate a warning if we should
      have sent an end cell for it but we haven't. Fixes bug 17876;
      bugfix on 0.2.3.2-alpha.

  o Minor bugfixes (configuration):
    - Fix a tiny memory leak when parsing a port configuration ending in
      ":auto". Fixes bug 18374; bugfix on 0.2.3.3-alpha.

  o Minor bugfixes (containers):
    - If we somehow attempt to construct a heap with more than
      1073741822 elements, avoid an integer overflow when maintaining
      the heap property. Fixes bug 18296; bugfix on 0.1.2.1-alpha.

  o Minor bugfixes (controller, microdescriptors):
    - Make GETINFO dir/status-vote/current/consensus conform to the
      control specification by returning "551 Could not open cached
      consensus..." when not caching consensuses. Fixes bug 18920;
      bugfix on 0.2.2.6-alpha.

  o Minor bugfixes (crypto):
    - Check the return value of HMAC() and assert on failure. Fixes bug
      17658; bugfix on 0.2.3.6-alpha. Patch by teor.

  o Minor bugfixes (directories):
    - When fetching extrainfo documents, compare their SHA256 digests
      and Ed25519 signing key certificates with the routerinfo that led
      us to fetch them, rather than with the most recent routerinfo.
      Otherwise we generate many spurious warnings about mismatches.
      Fixes bug 17150; bugfix on 0.2.7.2-alpha.
    - When generating a URL for a directory server on an IPv6 address,
      wrap the IPv6 address in square brackets. Fixes bug 18051; bugfix
      on 0.2.3.9-alpha. Patch from Malek.

  o Minor bugfixes (downloading):
    - Predict more correctly whether we'll be downloading over HTTP when
      we determine the maximum length of a URL. This should avoid a
      "BUG" warning about the Squid HTTP proxy and its URL limits. Fixes
      bug 19191.

  o Minor bugfixes (exit policies, security):
    - Refresh an exit relay's exit policy when interface addresses
      change. Previously, tor only refreshed the exit policy when the
      configured external address changed. Fixes bug 18208; bugfix on
      0.2.7.3-rc. Patch by teor.

  o Minor bugfixes (fallback directories):
    - Mark fallbacks as "too busy" when they return a 503 response,
      rather than just marking authorities. Fixes bug 17572; bugfix on
      0.2.4.7-alpha. Patch by teor.
    - When requesting extrainfo descriptors from a trusted directory
      server, check whether it is an authority or a fallback directory
      which supports extrainfo descriptors. Fixes bug 18489; bugfix on
      0.2.4.7-alpha. Reported by atagar, patch by teor.

  o Minor bugfixes (hidden service, client):
    - Handle the case where the user makes several fast consecutive
      requests to the same .onion address. Previously, the first six
      requests would each trigger a descriptor fetch, each picking a
      directory (there are 6 overall) and the seventh one would fail
      because no directories were left, thereby triggering a close on
      all current directory connections asking for the hidden service.
      The solution here is to not close the connections if we have
      pending directory fetches. Fixes bug 15937; bugfix
      on 0.2.7.1-alpha.

  o Minor bugfixes (hidden service, control port):
    - Add the onion address to the HS_DESC event for the UPLOADED action
      both on success or failure. It was previously hardcoded with
      UNKNOWN. Fixes bug 16023; bugfix on 0.2.7.2-alpha.

  o Minor bugfixes (hidden service, directory):
    - Bridges now refuse "rendezvous2" (hidden service descriptor)
      publish attempts. Suggested by ticket 18332.

  o Minor bugfixes (IPv6):
    - Update the limits in max_dl_per_request for IPv6 address length.
      Fixes bug 17573; bugfix on 0.2.1.5-alpha.

  o Minor bugfixes (Linux seccomp2 sandbox):
    - Allow more syscalls when running with "Sandbox 1" enabled:
      sysinfo, getsockopt(SO_SNDBUF), and setsockopt(SO_SNDBUFFORCE). On
      some systems, these are required for Tor to start. Fixes bug
      18397; bugfix on 0.2.5.1-alpha. Patch from Daniel Pinto.
    - Allow IPPROTO_UDP datagram sockets when running with "Sandbox 1",
      so that get_interface_address6_via_udp_socket_hack() can work.
      Fixes bug 19660; bugfix on 0.2.5.1-alpha.
    - Allow the setrlimit syscall, and the prlimit and prlimit64
      syscalls, which some libc implementations use under the hood.
      Fixes bug 15221; bugfix on 0.2.5.1-alpha.
    - Avoid a 10-second delay when starting as a client with "Sandbox 1"
      enabled and no DNS resolvers configured. This should help TAILS
      start up faster. Fixes bug 18548; bugfix on 0.2.5.1-alpha.
    - Fix a crash when using offline master ed25519 keys with the Linux
      seccomp2 sandbox enabled. Fixes bug 17675; bugfix on 0.2.7.3-rc.
    - Allow statistics to be written to disk when "Sandbox 1" is
      enabled. Fixes bugs 19556 and 19957; bugfix on 0.2.5.1-alpha and
      0.2.6.1-alpha respectively.

  o Minor bugfixes (logging):
    - In log messages that include a function name, use __FUNCTION__
      instead of __PRETTY_FUNCTION__. In GCC, these are synonymous, but
      with clang __PRETTY_FUNCTION__ has extra information we don't
      need. Fixes bug 16563; bugfix on 0.0.2pre8. Fix by Tom van
      der Woerdt.
    - Remove needless quotes from a log message about unparseable
      addresses. Fixes bug 17843; bugfix on 0.2.3.3-alpha.
    - Scrub service name in "unrecognized service ID" log messages.
      Fixes bug 18600; bugfix on 0.2.4.11-alpha.
    - When logging information about an unparsable networkstatus vote or
      consensus, do not say "vote" when we mean consensus. Fixes bug
      18368; bugfix on 0.2.0.8-alpha.
    - When we can't generate a signing key because OfflineMasterKey is
      set, do not imply that we should have been able to load it. Fixes
      bug 18133; bugfix on 0.2.7.2-alpha.
    - When logging a malformed hostname received through socks4, scrub
      it if SafeLogging says we should. Fixes bug 17419; bugfix
      on 0.1.1.16-rc.

  o Minor bugfixes (memory safety):
    - Avoid freeing an uninitialized pointer when opening a socket fails
      in get_interface_addresses_ioctl(). Fixes bug 18454; bugfix on
      0.2.3.11-alpha. Reported by toralf and "cypherpunks", patch
      by teor.
    - Fix a memory leak in "tor --list-fingerprint". Fixes part of bug
      18672; bugfix on 0.2.5.1-alpha.
    - Fix a memory leak in tor-gencert. Fixes part of bug 18672; bugfix
      on 0.2.0.1-alpha.

  o Minor bugfixes (pluggable transports):
    - Avoid reporting a spurious error when we decide that we don't need
      to terminate a pluggable transport because it has already exited.
      Fixes bug 18686; bugfix on 0.2.5.5-alpha.

  o Minor bugfixes (pointer arithmetic):
    - Fix a bug in memarea_alloc() that could have resulted in remote
      heap write access, if Tor had ever passed an unchecked size to
      memarea_alloc(). Fortunately, all the sizes we pass to
      memarea_alloc() are pre-checked to be less than 128 kilobytes.
      Fixes bug 19150; bugfix on 0.2.1.1-alpha. Bug found by
      Guido Vranken.

  o Minor bugfixes (private directory):
    - Prevent a race condition when creating private directories. Fixes
      part of bug 17852; bugfix on 0.0.2pre13. Part of ticket 17852.
      Patch from jsturgix. Found with Flawfinder.

  o Minor bugfixes (relays):
    - Check that both the ORPort and DirPort (if present) are reachable
      before publishing a relay descriptor. Otherwise, relays publish a
      descriptor with DirPort 0 when the DirPort reachability test takes
      longer than the ORPort reachability test. Fixes bug 18050; bugfix
      on 0.1.0.1-rc. Reported by "starlight", patch by teor.
    - Resolve some edge cases where we might launch an ORPort
      reachability check even when DisableNetwork is set. Noticed while
      fixing bug 18616; bugfix on 0.2.3.9-alpha.

  o Minor bugfixes (relays, hidden services):
    - Refuse connection requests to private OR addresses unless
      ExtendAllowPrivateAddresses is set. Previously, tor would connect,
      then refuse to send any cells to a private address. Fixes bugs
      17674 and 8976; bugfix on 0.2.3.21-rc. Patch by teor.

  o Minor bugfixes (security, hidden services):
    - Prevent hidden services connecting to client-supplied rendezvous
      addresses that are reserved as internal or multicast. Fixes bug
      8976; bugfix on 0.2.3.21-rc. Patch by dgoulet and teor.

  o Minor bugfixes (statistics):
    - Consistently check for overflow in round_*_to_next_multiple_of
      functions, and add unit tests with additional and maximal values.
      Fixes part of bug 13192; bugfix on 0.2.2.1-alpha.
    - Handle edge cases in the laplace functions: avoid division by
      zero, avoid taking the log of zero, and silence clang type
      conversion warnings using round and trunc. Add unit tests for edge
      cases with maximal values. Fixes part of bug 13192; bugfix
      on 0.2.6.2-alpha.
    - We now include consensus downloads via IPv6 in our directory-
      request statistics. Fixes bug 18460; bugfix on 0.2.3.14-alpha.

  o Minor bugfixes (test networks, IPv6):
    - Allow internal IPv6 addresses in descriptors in test networks.
      Fixes bug 17153; bugfix on 0.2.3.16-alpha. Patch by teor, reported
      by karsten.

  o Minor bugfixes (testing):
    - Check the full results of SHA256 and SHA512 digests in the unit
      tests. Bugfix on 0.2.2.4-alpha. Patch by teor.
    - Fix a memory leak in the ntor test. Fixes bug 17778; bugfix
      on 0.2.4.8-alpha.
    - Fix a small memory leak that would occur when the
      TestingEnableCellStatsEvent option was turned on. Fixes bug 18673;
      bugfix on 0.2.5.2-alpha.
    - Make unit tests pass on IPv6-only systems, and systems without
      localhost addresses (like some FreeBSD jails). Fixes bug 17632;
      bugfix on 0.2.7.3-rc. Patch by teor.
    - The test for log_heartbeat was incorrectly failing in timezones
      with non-integer offsets. Instead of comparing the end of the time
      string against a constant, compare it to the output of
      format_local_iso_time when given the correct input. Fixes bug
      18039; bugfix on 0.2.5.4-alpha.
    - We no longer disable assertions in the unit tests when coverage is
      enabled. Instead, we require you to say --disable-asserts-in-tests
      to the configure script if you need assertions disabled in the
      unit tests (for example, if you want to perform branch coverage).
      Fixes bug 18242; bugfix on 0.2.7.1-alpha.

  o Minor bugfixes (time handling):
    - When correcting a corrupt 'struct tm' value, fill in the tm_wday
      field. Otherwise, our unit tests crash on Windows. Fixes bug
      18977; bugfix on 0.2.2.25-alpha.
    - Avoid overflow in tor_timegm when parsing dates in and after 2038
      on platforms with 32-bit time_t. Fixes bug 18479; bugfix on
      0.0.2pre14. Patch by teor.

  o Minor bugfixes (tor-gencert):
    - Correctly handle the case where an authority operator enters a
      passphrase but sends an EOF before sending a newline. Fixes bug
      17443; bugfix on 0.2.0.20-rc. Found by junglefowl.

  o Code simplification and refactoring:
    - Clean up a little duplicated code in
      crypto_expand_key_material_TAP(). Closes ticket 17587; patch
      from "pfrankw".
    - Decouple the list of streams waiting to be attached to circuits
      from the overall connection list. This change makes it possible to
      attach streams quickly while simplifying Tor's callgraph and
      avoiding O(N) scans of the entire connection list. Closes
      ticket 17590.
    - Extract the more complicated parts of circuit_mark_for_close()
      into a new function that we run periodically before circuits are
      freed. This change removes more than half of the functions
      currently in the "blob". Closes ticket 17218.
    - Move logging of redundant policy entries in
      policies_parse_exit_policy_internal into its own function. Closes
      ticket 17608; patch from "juce".
    - Quote all the string interpolations in configure.ac -- even those
      which we are pretty sure can't contain spaces. Closes ticket
      17744. Patch from zerosion.
    - Remove code for configuring OpenSSL dynamic locks; OpenSSL doesn't
      use them. Closes ticket 17926.
    - Remove specialized code for non-inplace AES_CTR. 99% of our AES is
      inplace, so there's no need to have a separate implementation for
      the non-inplace code. Closes ticket 18258. Patch from Malek.
    - Simplify return types for some crypto functions that can't
      actually fail. Patch from Hassan Alsibyani. Closes ticket 18259.
    - When a direct directory request fails immediately on launch,
      instead of relaunching that request from inside the code that
      launches it, instead mark the connection for teardown. This change
      simplifies Tor's callback and prevents the directory-request
      launching code from invoking itself recursively. Closes
      ticket 17589.

  o Documentation:
    - Add a description of the correct use of the '--keygen' command-
      line option. Closes ticket 17583; based on text by 's7r'.
    - Change build messages to refer to "Fedora" instead of "Fedora
      Core", and "dnf" instead of "yum". Closes tickets 18459 and 18426.
      Patches from "icanhasaccount" and "cypherpunks".
    - Document the contents of the 'datadir/keys' subdirectory in the
      manual page. Closes ticket 17621.
    - Document the minimum HeartbeatPeriod value. Closes ticket 15638.
    - Explain actual minima for BandwidthRate. Closes ticket 16382.
    - Fix a minor formatting typo in the manpage. Closes ticket 17791.
    - Mention torspec URL in the manpage and point the reader to it
      whenever we mention a document that belongs in torspce. Fixes
      issue 17392.
    - Stop recommending use of nicknames to identify relays in our
      MapAddress documentation. Closes ticket 18312.

  o Removed features:
    - Remove client-side support for connecting to Tor relays running
      versions of Tor before 0.2.3.6-alpha. These relays didn't support
      the v3 TLS handshake protocol, and are no longer allowed on the
      Tor network. Implements the client side of ticket 11150. Based on
      patches by Tom van der Woerdt.
    - We no longer maintain an internal freelist in memarea.c.
      Allocators should be good enough to make this code unnecessary,
      and it's doubtful that it ever had any performance benefit.

  o Testing:
    - Add unit tests to check for common RNG failure modes, such as
      returning all zeroes, identical values, or incrementing values
      (OpenSSL's rand_predictable feature). Patch by teor.
    - Always test both ed25519 backends, so that we can be sure that our
      batch-open replacement code works. Part of ticket 16794.
    - Cover dns_resolve_impl() in dns.c with unit tests. Implements a
      portion of ticket 16831.
    - Fix several warnings from clang's address sanitizer produced in
      the unit tests.
    - Log more information when the backtrace tests fail. Closes ticket
      17892. Patch from "cypherpunks."
    - More unit tests for compat_libevent.c, procmon.c, tortls.c,
      util_format.c, directory.c, and options_validate.c. Closes tickets
      17075, 17082, 17084, 17003, and 17076 respectively. Patches from
      Ola Bini.
    - Treat backtrace test failures as expected on FreeBSD until we
      solve bug 17808. Closes ticket 18204.
    - Unit tests for directory_handle_command_get. Closes ticket 17004.
      Patch from Reinaldo de Souza Jr.


Changes in version 0.2.7.6 - 2015-12-10
  Tor version 0.2.7.6 fixes a major bug in entry guard selection, as
  well as a minor bug in hidden service reliability.

  o Major bugfixes (guard selection):
    - Actually look at the Guard flag when selecting a new directory
      guard. When we implemented the directory guard design, we
      accidentally started treating all relays as if they have the Guard
      flag during guard selection, leading to weaker anonymity and worse
      performance. Fixes bug 17772; bugfix on 0.2.4.8-alpha. Discovered
      by Mohsen Imani.

  o Minor features (geoip):
    - Update geoip and geoip6 to the December 1 2015 Maxmind GeoLite2
      Country database.

  o Minor bugfixes (compilation):
    - When checking for net/pfvar.h, include netinet/in.h if possible.
      This fixes transparent proxy detection on OpenBSD. Fixes bug
      17551; bugfix on 0.1.2.1-alpha. Patch from "rubiate".
    - Fix a compilation warning with Clang 3.6: Do not check the
      presence of an address which can never be NULL. Fixes bug 17781.

  o Minor bugfixes (correctness):
    - When displaying an IPv6 exit policy, include the mask bits
      correctly even when the number is greater than 31. Fixes bug
      16056; bugfix on 0.2.4.7-alpha. Patch from "gturner".
    - The wrong list was used when looking up expired intro points in a
      rend service object, causing what we think could be reachability
      issues for hidden services, and triggering a BUG log. Fixes bug
      16702; bugfix on 0.2.7.2-alpha.
    - Fix undefined behavior in the tor_cert_checksig function. Fixes
      bug 17722; bugfix on 0.2.7.2-alpha.


Changes in version 0.2.7.5 - 2015-11-20
  The Tor 0.2.7 release series is dedicated to the memory of Tor user
  and privacy advocate Caspar Bowden (1961-2015). Caspar worked
  tirelessly to advocate human rights regardless of national borders,
  and oppose the encroachments of mass surveillance. He opposed national
  exceptionalism, he brought clarity to legal and policy debates, he
  understood and predicted the impact of mass surveillance on the world,
  and he laid the groundwork for resisting it. While serving on the Tor
  Project's board of directors, he brought us his uncompromising focus
  on technical excellence in the service of humankind. Caspar was an
  inimitable force for good and a wonderful friend. He was kind,
  humorous, generous, gallant, and believed we should protect one
  another without exception. We honor him here for his ideals, his
  efforts, and his accomplishments. Please honor his memory with works
  that would make him proud.

  Tor 0.2.7.5 is the first stable release in the Tor 0.2.7 series.

  The 0.2.7 series adds a more secure identity key type for relays,
  improves cryptography performance, resolves several longstanding
  hidden-service performance issues, improves controller support for
  hidden services, and includes small bugfixes and performance
  improvements throughout the program. This release series also includes
  more tests than before, and significant simplifications to which parts
  of Tor invoke which others. For a full list of changes, see below.

  o New system requirements:
    - Tor no longer includes workarounds to support Libevent versions
      before 1.3e. Libevent 2.0 or later is recommended. Closes
      ticket 15248.
    - Tor no longer supports copies of OpenSSL that are missing support
      for Elliptic Curve Cryptography. (We began using ECC when
      available in 0.2.4.8-alpha, for more safe and efficient key
      negotiation.) In particular, support for at least one of P256 or
      P224 is now required, with manual configuration needed if only
      P224 is available. Resolves ticket 16140.
    - Tor no longer supports versions of OpenSSL before 1.0. (If you are
      on an operating system that has not upgraded to OpenSSL 1.0 or
      later, and you compile Tor from source, you will need to install a
      more recent OpenSSL to link Tor against.) These versions of
      OpenSSL are still supported by the OpenSSL, but the numerous
      cryptographic improvements in later OpenSSL releases makes them a
      clear choice. Resolves ticket 16034.

  o Major features (controller):
    - Add the ADD_ONION and DEL_ONION commands that allow the creation
      and management of hidden services via the controller. Closes
      ticket 6411.
    - New "GETINFO onions/current" and "GETINFO onions/detached"
      commands to get information about hidden services created via the
      controller. Part of ticket 6411.
    - New HSFETCH command to launch a request for a hidden service
      descriptor. Closes ticket 14847.
    - New HSPOST command to upload a hidden service descriptor. Closes
      ticket 3523. Patch by "DonnchaC".

  o Major features (Ed25519 identity keys, Proposal 220):
    - Add support for offline encrypted Ed25519 master keys. To use this
      feature on your tor relay, run "tor --keygen" to make a new master
      key (or to make a new signing key if you already have a master
      key). Closes ticket 13642.
    - All relays now maintain a stronger identity key, using the Ed25519
      elliptic curve signature format. This master key is designed so
      that it can be kept offline. Relays also generate an online
      signing key, and a set of other Ed25519 keys and certificates.
      These are all automatically regenerated and rotated as needed.
      Implements part of ticket 12498.
    - Directory authorities now vote on Ed25519 identity keys along with
      RSA1024 keys. Implements part of ticket 12498.
    - Directory authorities track which Ed25519 identity keys have been
      used with which RSA1024 identity keys, and do not allow them to
      vary freely. Implements part of ticket 12498.
    - Microdescriptors now include Ed25519 identity keys. Implements
      part of ticket 12498.
    - Add a --newpass option to allow changing or removing the
      passphrase of an encrypted key with tor --keygen. Implements part
      of ticket 16769.
    - Add a new OfflineMasterKey option to tell Tor never to try loading
      or generating a secret Ed25519 identity key. You can use this in
      combination with tor --keygen to manage offline and/or encrypted
      Ed25519 keys. Implements ticket 16944.
    - On receiving a HUP signal, check to see whether the Ed25519
      signing key has changed, and reload it if so. Closes ticket 16790.
    - Significant usability improvements for Ed25519 key management. Log
      messages are better, and the code can recover from far more
      failure conditions. Thanks to "s7r" for reporting and diagnosing
      so many of these!

  o Major features (ECC performance):
    - Improve the runtime speed of Ed25519 signature verification by
      using Ed25519-donna's batch verification support. Implements
      ticket 16533.
    - Improve the speed of Ed25519 operations and Curve25519 keypair
      generation when built targeting 32 bit x86 platforms with SSE2
      available. Implements ticket 16535.
    - Improve the runtime speed of Ed25519 operations by using the
      public-domain Ed25519-donna by Andrew M. ("floodyberry").
      Implements ticket 16467.
    - Improve the runtime speed of the ntor handshake by using an
      optimized curve25519 basepoint scalarmult implementation from the
      public-domain Ed25519-donna by Andrew M. ("floodyberry"), based on
      ideas by Adam Langley. Implements ticket 9663.

  o Major features (Hidden services):
    - Hidden services, if using the EntryNodes option, are required to
      use more than one EntryNode, in order to avoid a guard discovery
      attack. (This would only affect people who had configured hidden
      services and manually specified the EntryNodes option with a
      single entry-node. The impact was that it would be easy to
      remotely identify the guard node used by such a hidden service.
      See ticket for more information.) Fixes ticket 14917.
    - Add the torrc option HiddenServiceNumIntroductionPoints, to
      specify a fixed number of introduction points. Its maximum value
      is 10 and default is 3. Using this option can increase a hidden
      service's reliability under load, at the cost of making it more
      visible that the hidden service is facing extra load. Closes
      ticket 4862.
    - Remove the adaptive algorithm for choosing the number of
      introduction points, which used to change the number of
      introduction points (poorly) depending on the number of
      connections the HS sees. Closes ticket 4862.

  o Major features (onion key cross-certification):
    - Relay descriptors now include signatures of their own identity
      keys, made using the TAP and ntor onion keys. These signatures
      allow relays to prove ownership of their own onion keys. Because
      of this change, microdescriptors will no longer need to include
      RSA identity keys. Implements proposal 228; closes ticket 12499.

  o Major bugfixes (client-side privacy, also in 0.2.6.9):
    - Properly separate out each SOCKSPort when applying stream
      isolation. The error occurred because each port's session group
      was being overwritten by a default value when the listener
      connection was initialized. Fixes bug 16247; bugfix on
      0.2.6.3-alpha. Patch by "jojelino".

  o Major bugfixes (hidden service clients, stability, also in 0.2.6.10):
    - Stop refusing to store updated hidden service descriptors on a
      client. This reverts commit 9407040c59218 (which indeed fixed bug
      14219, but introduced a major hidden service reachability
      regression detailed in bug 16381). This is a temporary fix since
      we can live with the minor issue in bug 14219 (it just results in
      some load on the network) but the regression of 16381 is too much
      of a setback. First-round fix for bug 16381; bugfix
      on 0.2.6.3-alpha.

  o Major bugfixes (hidden services):
    - Revert commit that made directory authorities assign the HSDir
      flag to relay without a DirPort; this was bad because such relays
      can't handle BEGIN_DIR cells. Fixes bug 15850; bugfix
      on 0.2.6.3-alpha.
    - When cannibalizing a circuit for an introduction point, always
      extend to the chosen exit node (creating a 4 hop circuit).
      Previously Tor would use the current circuit exit node, which
      changed the original choice of introduction point, and could cause
      the hidden service to skip excluded introduction points or
      reconnect to a skipped introduction point. Fixes bug 16260; bugfix
      on 0.1.0.1-rc.

  o Major bugfixes (memory leaks):
    - Fix a memory leak in ed25519 batch signature checking. Fixes bug
      17398; bugfix on 0.2.6.1-alpha.

  o Major bugfixes (open file limit):
    - The open file limit wasn't checked before calling
      tor_accept_socket_nonblocking(), which would make Tor exceed the
      limit. Now, before opening a new socket, Tor validates the open
      file limit just before, and if the max has been reached, return an
      error. Fixes bug 16288; bugfix on 0.1.1.1-alpha.

  o Major bugfixes (security, correctness):
    - Fix an error that could cause us to read 4 bytes before the
      beginning of an openssl string. This bug could be used to cause
      Tor to crash on systems with unusual malloc implementations, or
      systems with unusual hardening installed. Fixes bug 17404; bugfix
      on 0.2.3.6-alpha.

  o Major bugfixes (stability, also in 0.2.6.10):
    - Stop crashing with an assertion failure when parsing certain kinds
      of malformed or truncated microdescriptors. Fixes bug 16400;
      bugfix on 0.2.6.1-alpha. Found by "torkeln"; fix based on a patch
      by "cypherpunks_backup".
    - Stop random client-side assertion failures that could occur when
      connecting to a busy hidden service, or connecting to a hidden
      service while a NEWNYM is in progress. Fixes bug 16013; bugfix
      on 0.1.0.1-rc.

  o Minor features (client, SOCKS):
    - Add GroupWritable and WorldWritable options to unix-socket based
      SocksPort and ControlPort options. These options apply to a single
      socket, and override {Control,Socks}SocketsGroupWritable. Closes
      ticket 15220.
    - Relax the validation done to hostnames in SOCKS5 requests, and
      allow a single trailing '.' to cope with clients that pass FQDNs
      using that syntax to explicitly indicate that the domain name is
      fully-qualified. Fixes bug 16674; bugfix on 0.2.6.2-alpha.
    - Relax the validation of hostnames in SOCKS5 requests, allowing the
      character '_' to appear, in order to cope with domains observed in
      the wild that are serving non-RFC compliant records. Resolves
      ticket 16430.

  o Minor features (client-side privacy):
    - New KeepAliveIsolateSOCKSAuth option to indefinitely extend circuit
      lifespan when IsolateSOCKSAuth and streams with SOCKS
      authentication are attached to the circuit. This allows
      applications like TorBrowser to manage circuit lifetime on their
      own. Implements feature 15482.
    - When logging malformed hostnames from SOCKS5 requests, respect
      SafeLogging configuration. Fixes bug 16891; bugfix on 0.1.1.16-rc.

  o Minor features (clock-jump tolerance):
    - Recover better when our clock jumps back many hours, like might
      happen for Tails or Whonix users who start with a very wrong
      hardware clock, use Tor to discover a more accurate time, and then
      fix their clock. Resolves part of ticket 8766.

  o Minor features (command-line interface):
    - Make --hash-password imply --hush to prevent unnecessary noise.
      Closes ticket 15542. Patch from "cypherpunks".
    - Print a warning whenever we find a relative file path being used
      as torrc option. Resolves issue 14018.

  o Minor features (compilation):
    - Give a warning as early as possible when trying to build with an
      unsupported OpenSSL version. Closes ticket 16901.
    - Use C99 variadic macros when the compiler is not GCC. This avoids
      failing compilations on MSVC, and fixes a log-file-based race
      condition in our old workarounds. Original patch from Gisle Vanem.

  o Minor features (control protocol):
    - Support network-liveness GETINFO key and NETWORK_LIVENESS event in
      the control protocol. Resolves ticket 15358.

  o Minor features (controller):
    - Add DirAuthority lines for default directory authorities to the
      output of the "GETINFO config/defaults" command if not already
      present. Implements ticket 14840.
    - Controllers can now use "GETINFO hs/client/desc/id/..." to
      retrieve items from the client's hidden service descriptor cache.
      Closes ticket 14845.
    - Implement a new controller command "GETINFO status/fresh-relay-
      descs" to fetch a descriptor/extrainfo pair that was generated on
      demand just for the controller's use. Implements ticket 14784.

  o Minor features (directory authorities):
    - Directory authorities no longer vote against the "Fast", "Stable",
      and "HSDir" flags just because they were going to vote against
      "Running": if the consensus turns out to be that the router was
      running, then the authority's vote should count. Patch from Peter
      Retzlaff; closes issue 8712.

  o Minor features (directory authorities, security, also in 0.2.6.9):
    - The HSDir flag given by authorities now requires the Stable flag.
      For the current network, this results in going from 2887 to 2806
      HSDirs. Also, it makes it harder for an attacker to launch a sybil
      attack by raising the effort for a relay to become Stable to
      require at the very least 7 days, while maintaining the 96 hours
      uptime requirement for HSDir. Implements ticket 8243.

  o Minor features (DoS-resistance):
    - Make it harder for attackers to overload hidden services with
      introductions, by blocking multiple introduction requests on the
      same circuit. Resolves ticket 15515.

  o Minor features (geoip):
    - Update geoip and geoip6 to the October 9 2015 Maxmind GeoLite2
      Country database.

  o Minor features (hidden services):
    - Add the new options "HiddenServiceMaxStreams" and
      "HiddenServiceMaxStreamsCloseCircuit" to allow hidden services to
      limit the maximum number of simultaneous streams per circuit, and
      optionally tear down the circuit when the limit is exceeded. Part
      of ticket 16052.
    - Client now uses an introduction point failure cache to know when
      to fetch or keep a descriptor in their cache. Previously, failures
      were recorded implicitly, but not explicitly remembered. Closes
      ticket 16389.
    - Relays need to have the Fast flag to get the HSDir flag. As this
      is being written, we'll go from 2745 HSDirs down to 2342, a ~14%
      drop. This change should make some attacks against the hidden
      service directory system harder. Fixes ticket 15963.
    - Turn on hidden service statistics collection by setting the torrc
      option HiddenServiceStatistics to "1" by default. (This keeps
      track only of the fraction of traffic used by hidden services, and
      the total number of hidden services in existence.) Closes
      ticket 15254.
    - To avoid leaking HS popularity, don't cycle the introduction point
      when we've handled a fixed number of INTRODUCE2 cells but instead
      cycle it when a random number of introductions is reached, thus
      making it more difficult for an attacker to find out the amount of
      clients that have used the introduction point for a specific HS.
      Closes ticket 15745.

  o Minor features (logging):
    - Include the Tor version in all LD_BUG log messages, since people
      tend to cut and paste those into the bugtracker. Implements
      ticket 15026.

  o Minor features (pluggable transports):
    - When launching managed pluggable transports on Linux systems,
      attempt to have the kernel deliver a SIGTERM on tor exit if the
      pluggable transport process is still running. Resolves
      ticket 15471.
    - When launching managed pluggable transports, setup a valid open
      stdin in the child process that can be used to detect if tor has
      terminated. The "TOR_PT_EXIT_ON_STDIN_CLOSE" environment variable
      can be used by implementations to detect this new behavior.
      Resolves ticket 15435.

  o Minor bugfixes (torrc exit policies):
    - In each instance above, usage advice is provided to avoid the
      message. Resolves ticket 16069. Patch by "teor". Fixes part of bug
      16069; bugfix on 0.2.4.7-alpha.
    - In torrc, "accept6 *" and "reject6 *" ExitPolicy lines now only
      produce IPv6 wildcard addresses. Previously they would produce
      both IPv4 and IPv6 wildcard addresses. Patch by "teor". Fixes part
      of bug 16069; bugfix on 0.2.4.7-alpha.
    - When parsing torrc ExitPolicies, we now issue an info-level
      message when expanding an "accept/reject *" line to include both
      IPv4 and IPv6 wildcard addresses. Related to ticket 16069.
    - When parsing torrc ExitPolicies, we now warn for a number of cases
      where the user's intent is likely to differ from Tor's actual
      behavior. These include: using an IPv4 address with an accept6 or
      reject6 line; using "private" on an accept6 or reject6 line; and
      including any ExitPolicy lines after accept *:* or reject *:*.
      Related to ticket 16069.

  o Minor bugfixes (command-line interface):
    - When "--quiet" is provided along with "--validate-config", do not
      write anything to stdout on success. Fixes bug 14994; bugfix
      on 0.2.3.3-alpha.
    - When complaining about bad arguments to "--dump-config", use
      stderr, not stdout.
    - Print usage information for --dump-config when it is used without
      an argument. Also, fix the error message to use different wording
      and add newline at the end. Fixes bug 15541; bugfix
      on 0.2.5.1-alpha.

  o Minor bugfixes (compilation):
    - Fix compilation of sandbox.c with musl-libc. Fixes bug 17347;
      bugfix on 0.2.5.1-alpha. Patch from 'jamestk'.
    - Repair compilation with the most recent (unreleased, alpha)
      vesions of OpenSSL 1.1. Fixes part of ticket 17237.

  o Minor bugfixes (compilation, also in 0.2.6.9):
    - Build with --enable-systemd correctly when libsystemd is
      installed, but systemd is not. Fixes bug 16164; bugfix on
      0.2.6.3-alpha. Patch from Peter Palfrader.

  o Minor bugfixes (configuration, unit tests):
    - Only add the default fallback directories when the DirAuthorities,
      AlternateDirAuthority, and FallbackDir directory config options
      are set to their defaults. The default fallback directory list is
      currently empty, this fix will only change tor's behavior when it
      has default fallback directories. Includes unit tests for
      consider_adding_dir_servers(). Fixes bug 15642; bugfix on
      90f6071d8dc0 in 0.2.4.7-alpha. Patch by "teor".

  o Minor bugfixes (controller):
    - Add the descriptor ID in each HS_DESC control event. It was
      missing, but specified in control-spec.txt. Fixes bug 15881;
      bugfix on 0.2.5.2-alpha.

  o Minor bugfixes (correctness):
    - For correctness, avoid modifying a constant string in
      handle_control_postdescriptor. Fixes bug 15546; bugfix
      on 0.1.1.16-rc.
    - Remove side-effects from tor_assert() calls. This was harmless,
      because we never disable assertions, but it is bad style and
      unnecessary. Fixes bug 15211; bugfix on 0.2.5.5, 0.2.2.36,
      and 0.2.0.10.
    - When calling channel_free_list(), avoid calling smartlist_remove()
      while inside a FOREACH loop. This partially reverts commit
      17356fe7fd96af where the correct SMARTLIST_DEL_CURRENT was
      incorrectly removed. Fixes bug 16924; bugfix on 0.2.4.4-alpha.

  o Minor bugfixes (crypto error-handling, also in 0.2.6.10):
    - Check for failures from crypto_early_init, and refuse to continue.
      A previous typo meant that we could keep going with an
      uninitialized crypto library, and would have OpenSSL initialize
      its own PRNG. Fixes bug 16360; bugfix on 0.2.5.2-alpha, introduced
      when implementing ticket 4900. Patch by "teor".

  o Minor bugfixes (hidden service):
    - Fix an out-of-bounds read when parsing invalid INTRODUCE2 cells on
      a client authorized hidden service. Fixes bug 15823; bugfix
      on 0.2.1.6-alpha.
    - Remove an extraneous newline character from the end of hidden
      service descriptors. Fixes bug 15296; bugfix on 0.2.0.10-alpha.

  o Minor bugfixes (Linux seccomp2 sandbox):
    - Use the sandbox in tor_open_cloexec whether or not O_CLOEXEC is
      defined. Patch by "teor". Fixes bug 16515; bugfix on 0.2.3.1-alpha.
    - Allow bridge authorities to run correctly under the seccomp2
      sandbox. Fixes bug 16964; bugfix on 0.2.5.1-alpha.
    - Add the "hidserv-stats" filename to our sandbox filter for the
      HiddenServiceStatistics option to work properly. Fixes bug 17354;
      bugfix on 0.2.6.2-alpha. Patch from David Goulet.

  o Minor bugfixes (Linux seccomp2 sandbox, also in 0.2.6.10):
    - Allow pipe() and pipe2() syscalls in the seccomp2 sandbox: we need
      these when eventfd2() support is missing. Fixes bug 16363; bugfix
      on 0.2.6.3-alpha. Patch from "teor".

  o Minor bugfixes (Linux seccomp2 sandbox, also in 0.2.6.9):
    - Allow systemd connections to work with the Linux seccomp2 sandbox
      code. Fixes bug 16212; bugfix on 0.2.6.2-alpha. Patch by
      Peter Palfrader.
    - Fix sandboxing to work when running as a relay, by allowing the
      renaming of secret_id_key, and allowing the eventfd2 and futex
      syscalls. Fixes bug 16244; bugfix on 0.2.6.1-alpha. Patch by
      Peter Palfrader.

  o Minor bugfixes (logging):
    - When building Tor under Clang, do not include an extra set of
      parentheses in log messages that include function names. Fixes bug
      15269; bugfix on every released version of Tor when compiled with
      recent enough Clang.

  o Minor bugfixes (network):
    - When attempting to use fallback technique for network interface
      lookup, disregard loopback and multicast addresses since they are
      unsuitable for public communications.

  o Minor bugfixes (open file limit):
    - Fix set_max_file_descriptors() to set by default the max open file
      limit to the current limit when setrlimit() fails. Fixes bug
      16274; bugfix on tor- 0.2.0.10-alpha. Patch by dgoulet.

  o Minor bugfixes (portability):
    - Check correctly for Windows socket errors in the workqueue
      backend. Fixes bug 16741; bugfix on 0.2.6.3-alpha.
    - Try harder to normalize the exit status of the Tor process to the
      standard-provided range. Fixes bug 16975; bugfix on every version
      of Tor ever.
    - Use libexecinfo on FreeBSD to enable backtrace support. Fixes part
      of bug 17151; bugfix on 0.2.5.2-alpha. Patch from Marcin Cieślak.

  o Minor bugfixes (relay):
    - Ensure that worker threads actually exit when a fatal error or
      shutdown is indicated. This fix doesn't currently affect the
      behavior of Tor, because Tor workers never indicates fatal error
      or shutdown except in the unit tests. Fixes bug 16868; bugfix
      on 0.2.6.3-alpha.
    - Fix a rarely-encountered memory leak when failing to initialize
      the thread pool. Fixes bug 16631; bugfix on 0.2.6.3-alpha. Patch
      from "cypherpunks".
    - Unblock threads before releasing the work queue mutex to ensure
      predictable scheduling behavior. Fixes bug 16644; bugfix
      on 0.2.6.3-alpha.

  o Minor bugfixes (security, exit policies):
    - ExitPolicyRejectPrivate now also rejects the relay's published
      IPv6 address (if any), and any publicly routable IPv4 or IPv6
      addresses on any local interfaces. ticket 17027. Patch by "teor".
      Fixes bug 17027; bugfix on 0.2.0.11-alpha.

  o Minor bugfixes (statistics):
    - Disregard the ConnDirectionStatistics torrc options when Tor is
      not a relay since in that mode of operation no sensible data is
      being collected and because Tor might run into measurement hiccups
      when running as a client for some time, then becoming a relay.
      Fixes bug 15604; bugfix on 0.2.2.35.

  o Minor bugfixes (systemd):
    - Tor's systemd unit file no longer contains extraneous spaces.
      These spaces would sometimes confuse tools like deb-systemd-
      helper. Fixes bug 16162; bugfix on 0.2.5.5-alpha.

  o Minor bugfixes (test networks):
    - When self-testing reachability, use ExtendAllowPrivateAddresses to
      determine if local/private addresses imply reachability. The
      previous fix used TestingTorNetwork, which implies
      ExtendAllowPrivateAddresses, but this excluded rare configurations
      where ExtendAllowPrivateAddresses is set but TestingTorNetwork is
      not. Fixes bug 15771; bugfix on 0.2.6.1-alpha. Patch by "teor",
      issue discovered by CJ Ess.

  o Minor bugfixes (tests, also in 0.2.6.9):
    - Fix a crash in the unit tests when built with MSVC2013. Fixes bug
      16030; bugfix on 0.2.6.2-alpha. Patch from "NewEraCracker".

  o Code simplification and refactoring:
    - Change the function that's called when we need to retry all
      downloads so that it only reschedules the downloads to happen
      immediately, rather than launching them all at once itself. This
      further simplifies Tor's callgraph.
    - Define WINVER and _WIN32_WINNT centrally, in orconfig.h, in order
      to ensure they remain consistent and visible everywhere.
    - Move some format-parsing functions out of crypto.c and
      crypto_curve25519.c into crypto_format.c and/or util_format.c.
    - Move the client-only parts of init_keys() into a separate
      function. Closes ticket 16763.
    - Move the hacky fallback code out of get_interface_address6() into
      separate function and get it covered with unit-tests. Resolves
      ticket 14710.
    - Refactor hidden service client-side cache lookup to intelligently
      report its various failure cases, and disentangle failure cases
      involving a lack of introduction points. Closes ticket 14391.
    - Remove some vestigial workarounds for the MSVC6 compiler. We
      haven't supported that in ages.
    - Remove the unused "nulterminate" argument from buf_pullup().
    - Simplify the microdesc_free() implementation so that it no longer
      appears (to code analysis tools) to potentially invoke a huge
      suite of other microdesc functions.
    - Simply the control graph further by deferring the inner body of
      directory_all_unreachable() into a callback. Closes ticket 16762.
    - The link authentication code has been refactored for better
      testability and reliability. It now uses code generated with the
      "trunnel" binary encoding generator, to reduce the risk of bugs
      due to programmer error. Done as part of ticket 12498.
    - Treat the loss of an owning controller as equivalent to a SIGTERM
      signal. This removes a tiny amount of duplicated code, and
      simplifies our callgraph. Closes ticket 16788.
    - Use our own Base64 encoder instead of OpenSSL's, to allow more
      control over the output. Part of ticket 15652.
    - When generating an event to send to the controller, we no longer
      put the event over the network immediately. Instead, we queue
      these events, and use a Libevent callback to deliver them. This
      change simplifies Tor's callgraph by reducing the number of
      functions from which all other Tor functions are reachable. Closes
      ticket 16695.
    - Wrap Windows-only C files inside '#ifdef _WIN32' so that tools
      that try to scan or compile every file on Unix won't decide that
      they are broken.

  o Documentation:
    - Fix capitalization of SOCKS in sample torrc. Closes ticket 15609.
    - Improve the descriptions of statistics-related torrc options in
      the manpage to describe rationale and possible uses cases. Fixes
      issue 15550.
    - Improve the layout and formatting of ./configure --help messages.
      Closes ticket 15024. Patch from "cypherpunks".
    - Include a specific and (hopefully) accurate documentation of the
      torrc file's meta-format in doc/torrc_format.txt. This is mainly
      of interest to people writing programs to parse or generate torrc
      files. This document is not a commitment to long-term
      compatibility; some aspects of the current format are a bit
      ridiculous. Closes ticket 2325.
    - Include the TUNING document in our source tarball. It is referred
      to in the ChangeLog and an error message. Fixes bug 16929; bugfix
      on 0.2.6.1-alpha.
    - Note that HiddenServicePorts can take a unix domain socket. Closes
      ticket 17364.
    - Recommend a 40 GB example AccountingMax in torrc.sample rather
      than a 4 GB max. Closes ticket 16742.
    - Standardize on the term "server descriptor" in the manual page.
      Previously, we had used "router descriptor", "server descriptor",
      and "relay descriptor" interchangeably. Part of ticket 14987.
    - Advise users on how to configure separate IPv4 and IPv6 exit
      policies in the manpage and sample torrcs. Related to ticket 16069.
    - Fix an error in the manual page and comments for
      TestingDirAuthVoteHSDir[IsStrict], which suggested that a HSDir
      required "ORPort connectivity". While this is true, it is in no
      way unique to the HSDir flag. Of all the flags, only HSDirs need a
      DirPort configured in order for the authorities to assign that
      particular flag. Patch by "teor". Fixed as part of 14882; bugfix
      on 0.2.6.3-alpha.
    - Fix the usage message of tor-resolve(1) so that it no longer lists
      the removed -F option. Fixes bug 16913; bugfix on 0.2.2.28-beta.

  o Removed code:
    - Remove `USE_OPENSSL_BASE64` and the corresponding fallback code
      and always use the internal Base64 decoder. The internal decoder
      has been part of tor since 0.2.0.10-alpha, and no one should
      be using the OpenSSL one. Part of ticket 15652.
    - Remove the 'tor_strclear()' function; use memwipe() instead.
      Closes ticket 14922.
    - Remove the code that would try to aggressively flush controller
      connections while writing to them. This code was introduced in
      0.1.2.7-alpha, in order to keep output buffers from exceeding
      their limits. But there is no longer a maximum output buffer size,
      and flushing data in this way caused some undesirable recursions
      in our call graph. Closes ticket 16480.
    - The internal pure-C tor-fw-helper tool is now removed from the Tor
      distribution, in favor of the pure-Go clone available from
      https://gitweb.torproject.org/tor-fw-helper.git/ . The libraries
      used by the C tor-fw-helper are not, in our opinion, very
      confidence- inspiring in their secure-programming techniques.
      Closes ticket 13338.

  o Removed features:
    - Remove the (seldom-used) DynamicDHGroups feature. For anti-
      fingerprinting we now recommend pluggable transports; for forward-
      secrecy in TLS, we now use the P-256 group. Closes ticket 13736.
    - Remove the HidServDirectoryV2 option. Now all relays offer to
      store hidden service descriptors. Related to 16543.
    - Remove the VoteOnHidServDirectoriesV2 option, since all
      authorities have long set it to 1. Closes ticket 16543.
    - Remove the undocumented "--digests" command-line option. It
      complicated our build process, caused subtle build issues on
      multiple platforms, and is now redundant since we started
      including git version identifiers. Closes ticket 14742.
    - Tor no longer contains checks for ancient directory cache versions
      that didn't know about microdescriptors.
    - Tor no longer contains workarounds for stat files generated by
      super-old versions of Tor that didn't choose guards sensibly.

  o Testing:
    - The test-network.sh script now supports performance testing.
      Requires corresponding chutney performance testing changes. Patch
      by "teor". Closes ticket 14175.
    - Add a new set of callgraph analysis scripts that use clang to
      produce a list of which Tor functions are reachable from which
      other Tor functions. We're planning to use these to help simplify
      our code structure by identifying illogical dependencies.
    - Add new 'test-full' and 'test-full-online' targets to run all
      tests, including integration tests with stem and chutney.
    - Autodetect CHUTNEY_PATH if the chutney and Tor sources are side-
      by-side in the same parent directory. Closes ticket 16903. Patch
      by "teor".
    - Document use of coverity, clang static analyzer, and clang dynamic
      undefined behavior and address sanitizers in doc/HACKING. Include
      detailed usage instructions in the blacklist. Patch by "teor".
      Closes ticket 15817.
    - Make "bridges+hs" the default test network. This tests almost all
      tor functionality during make test-network, while allowing tests
      to succeed on non-IPv6 systems. Requires chutney commit 396da92 in
      test-network-bridges-hs. Closes tickets 16945 (tor) and 16946
      (chutney). Patches by "teor".
    - Make the test-workqueue test work on Windows by initializing the
      network before we begin.
    - New make target (make test-network-all) to run multiple applicable
      chutney test cases. Patch from Teor; closes 16953.
    - Now that OpenSSL has its own scrypt implementation, add an unit
      test that checks for interoperability between libscrypt_scrypt()
      and OpenSSL's EVP_PBE_scrypt() so that we could not use libscrypt
      and rely on EVP_PBE_scrypt() whenever possible. Resolves
      ticket 16189.
    - The link authentication protocol code now has extensive tests.
    - The relay descriptor signature testing code now has
      extensive tests.
    - The test_workqueue program now runs faster, and is enabled by
      default as a part of "make check".
    - Unit test dns_resolve(), dns_clip_ttl() and dns_get_expiry_ttl()
      functions in dns.c. Implements a portion of ticket 16831.
    - Use environment variables rather than autoconf substitutions to
      send variables from the build system to the test scripts. This
      change should be easier to maintain, and cause 'make distcheck' to
      work better than before. Fixes bug 17148.
    - When building Tor with testing coverage enabled, run Chutney tests
      (if any) using the 'tor-cov' coverage binary.
    - When running test-network or test-stem, check for the absence of
      stem/chutney before doing any build operations.
    - Add a test to verify that the compiler does not eliminate our
      memwipe() implementation. Closes ticket 15377.
    - Add make rule `check-changes` to verify the format of changes
      files. Closes ticket 15180.
    - Add unit tests for control_event_is_interesting(). Add a compile-
      time check that the number of events doesn't exceed the capacity
      of control_event_t.event_mask. Closes ticket 15431, checks for
      bugs similar to 13085. Patch by "teor".
    - Command-line argument tests moved to Stem. Resolves ticket 14806.
    - Integrate the ntor, backtrace, and zero-length keys tests into the
      automake test suite. Closes ticket 15344.
    - Remove assertions during builds to determine Tor's test coverage.
      We don't want to trigger these even in assertions, so including
      them artificially makes our branch coverage look worse than it is.
      This patch provides the new test-stem-full and coverage-html-full
      configure options. Implements ticket 15400.
    - New TestingDirAuthVote{Exit,Guard,HSDir}IsStrict flags to
      explicitly manage consensus flags in testing networks. Patch by
      "robgjansen", modified by "teor". Implements part of ticket 14882.
    - Check for matching value in server response in ntor_ref.py. Fixes
      bug 15591; bugfix on 0.2.4.8-alpha. Reported and fixed
      by "joelanders".
    - Set the severity correctly when testing
      get_interface_addresses_ifaddrs() and
      get_interface_addresses_win32(), so that the tests fail gracefully
      instead of triggering an assertion. Fixes bug 15759; bugfix on
      0.2.6.3-alpha. Reported by Nicolas Derive.

Changes in version 0.2.6.10 - 2015-07-12
  Tor version 0.2.6.10 fixes some significant stability and hidden
  service client bugs, bulletproofs the cryptography init process, and
  fixes a bug when using the sandbox code with some older versions of
  Linux. Everyone running an older version, especially an older version
  of 0.2.6, should upgrade.

  o Major bugfixes (hidden service clients, stability):
    - Stop refusing to store updated hidden service descriptors on a
      client. This reverts commit 9407040c59218 (which indeed fixed bug
      14219, but introduced a major hidden service reachability
      regression detailed in bug 16381). This is a temporary fix since
      we can live with the minor issue in bug 14219 (it just results in
      some load on the network) but the regression of 16381 is too much
      of a setback. First-round fix for bug 16381; bugfix
      on 0.2.6.3-alpha.

  o Major bugfixes (stability):
    - Stop crashing with an assertion failure when parsing certain kinds
      of malformed or truncated microdescriptors. Fixes bug 16400;
      bugfix on 0.2.6.1-alpha. Found by "torkeln"; fix based on a patch
      by "cypherpunks_backup".
    - Stop random client-side assertion failures that could occur when
      connecting to a busy hidden service, or connecting to a hidden
      service while a NEWNYM is in progress. Fixes bug 16013; bugfix
      on 0.1.0.1-rc.

  o Minor features (geoip):
    - Update geoip to the June 3 2015 Maxmind GeoLite2 Country database.
    - Update geoip6 to the June 3 2015 Maxmind GeoLite2 Country database.

  o Minor bugfixes (crypto error-handling):
    - Check for failures from crypto_early_init, and refuse to continue.
      A previous typo meant that we could keep going with an
      uninitialized crypto library, and would have OpenSSL initialize
      its own PRNG. Fixes bug 16360; bugfix on 0.2.5.2-alpha, introduced
      when implementing ticket 4900. Patch by "teor".

  o Minor bugfixes (Linux seccomp2 sandbox):
    - Allow pipe() and pipe2() syscalls in the seccomp2 sandbox: we need
      these when eventfd2() support is missing. Fixes bug 16363; bugfix
      on 0.2.6.3-alpha. Patch from "teor".


Changes in version 0.2.6.9 - 2015-06-11
  Tor 0.2.6.9 fixes a regression in the circuit isolation code, increases the
  requirements for receiving an HSDir flag, and addresses some other small
  bugs in the systemd and sandbox code. Clients using circuit isolation
  should upgrade; all directory authorities should upgrade.

  o Major bugfixes (client-side privacy):
    - Properly separate out each SOCKSPort when applying stream
      isolation. The error occurred because each port's session group was
      being overwritten by a default value when the listener connection
      was initialized. Fixes bug 16247; bugfix on 0.2.6.3-alpha. Patch
      by "jojelino".

  o Minor feature (directory authorities, security):
    - The HSDir flag given by authorities now requires the Stable flag.
      For the current network, this results in going from 2887 to 2806
      HSDirs. Also, it makes it harder for an attacker to launch a sybil
      attack by raising the effort for a relay to become Stable which
      takes at the very least 7 days to do so and by keeping the 96
      hours uptime requirement for HSDir. Implements ticket 8243.

  o Minor bugfixes (compilation):
    - Build with --enable-systemd correctly when libsystemd is
      installed, but systemd is not. Fixes bug 16164; bugfix on
      0.2.6.3-alpha. Patch from Peter Palfrader.

  o Minor bugfixes (Linux seccomp2 sandbox):
    - Fix sandboxing to work when running as a relaymby renaming of
      secret_id_key, and allowing the eventfd2 and futex syscalls. Fixes
      bug 16244; bugfix on 0.2.6.1-alpha. Patch by Peter Palfrader.
    - Allow systemd connections to work with the Linux seccomp2 sandbox
      code. Fixes bug 16212; bugfix on 0.2.6.2-alpha. Patch by
      Peter Palfrader.

  o Minor bugfixes (tests):
    - Fix a crash in the unit tests when built with MSVC2013. Fixes bug
      16030; bugfix on 0.2.6.2-alpha. Patch from "NewEraCracker".


Changes in version 0.2.6.8 - 2015-05-21
  Tor 0.2.6.8 fixes a bit of dodgy code in parsing INTRODUCE2 cells, and
  fixes an authority-side bug in assigning the HSDir flag. All directory
  authorities should upgrade.

  o Major bugfixes (hidden services, backport from 0.2.7.1-alpha):
    - Revert commit that made directory authorities assign the HSDir
      flag to relay without a DirPort; this was bad because such relays
      can't handle BEGIN_DIR cells. Fixes bug 15850; bugfix
      on 0.2.6.3-alpha.

  o Minor bugfixes (hidden service, backport from 0.2.7.1-alpha):
    - Fix an out-of-bounds read when parsing invalid INTRODUCE2 cells on
      a client authorized hidden service. Fixes bug 15823; bugfix
      on 0.2.1.6-alpha.

  o Minor features (geoip):
    - Update geoip to the April 8 2015 Maxmind GeoLite2 Country database.
    - Update geoip6 to the April 8 2015 Maxmind GeoLite2
      Country database.


Changes in version 0.2.6.7 - 2015-04-06
  Tor 0.2.6.7 fixes two security issues that could be used by an
  attacker to crash hidden services, or crash clients visiting hidden
  services. Hidden services should upgrade as soon as possible; clients
  should upgrade whenever packages become available.

  This release also contains two simple improvements to make hidden
  services a bit less vulnerable to denial-of-service attacks.

  o Major bugfixes (security, hidden service):
    - Fix an issue that would allow a malicious client to trigger an
      assertion failure and halt a hidden service. Fixes bug 15600;
      bugfix on 0.2.1.6-alpha. Reported by "disgleirio".
    - Fix a bug that could cause a client to crash with an assertion
      failure when parsing a malformed hidden service descriptor. Fixes
      bug 15601; bugfix on 0.2.1.5-alpha. Found by "DonnchaC".

  o Minor features (DoS-resistance, hidden service):
    - Introduction points no longer allow multiple INTRODUCE1 cells to
      arrive on the same circuit. This should make it more expensive for
      attackers to overwhelm hidden services with introductions.
      Resolves ticket 15515.
    - Decrease the amount of reattempts that a hidden service performs
      when its rendezvous circuits fail. This reduces the computational
      cost for running a hidden service under heavy load. Resolves
      ticket 11447.


Changes in version 0.2.5.12 - 2015-04-06
  Tor 0.2.5.12 backports two fixes from 0.2.6.7 for security issues that
  could be used by an attacker to crash hidden services, or crash clients
  visiting hidden services. Hidden services should upgrade as soon as
  possible; clients should upgrade whenever packages become available.

  This release also backports a simple improvement to make hidden
  services a bit less vulnerable to denial-of-service attacks.

  o Major bugfixes (security, hidden service):
    - Fix an issue that would allow a malicious client to trigger an
      assertion failure and halt a hidden service. Fixes bug 15600;
      bugfix on 0.2.1.6-alpha. Reported by "disgleirio".
    - Fix a bug that could cause a client to crash with an assertion
      failure when parsing a malformed hidden service descriptor. Fixes
      bug 15601; bugfix on 0.2.1.5-alpha. Found by "DonnchaC".

  o Minor features (DoS-resistance, hidden service):
    - Introduction points no longer allow multiple INTRODUCE1 cells to
      arrive on the same circuit. This should make it more expensive for
      attackers to overwhelm hidden services with introductions.
      Resolves ticket 15515.


Changes in version 0.2.4.27 - 2015-04-06
  Tor 0.2.4.27 backports two fixes from 0.2.6.7 for security issues that
  could be used by an attacker to crash hidden services, or crash clients
  visiting hidden services. Hidden services should upgrade as soon as
  possible; clients should upgrade whenever packages become available.

  This release also backports a simple improvement to make hidden
  services a bit less vulnerable to denial-of-service attacks.

  o Major bugfixes (security, hidden service):
    - Fix an issue that would allow a malicious client to trigger an
      assertion failure and halt a hidden service. Fixes bug 15600;
      bugfix on 0.2.1.6-alpha. Reported by "disgleirio".
    - Fix a bug that could cause a client to crash with an assertion
      failure when parsing a malformed hidden service descriptor. Fixes
      bug 15601; bugfix on 0.2.1.5-alpha. Found by "DonnchaC".

  o Minor features (DoS-resistance, hidden service):
    - Introduction points no longer allow multiple INTRODUCE1 cells to
      arrive on the same circuit. This should make it more expensive for
      attackers to overwhelm hidden services with introductions.
      Resolves ticket 15515.


Changes in version 0.2.6.6 - 2015-03-24
  Tor 0.2.6.6 is the first stable release in the 0.2.6 series.

  It adds numerous safety, security, correctness, and performance
  improvements. Client programs can be configured to use more kinds of
  sockets, AutomapHosts works better, the multithreading backend is
  improved, cell transmission is refactored, test coverage is much
  higher, more denial-of-service attacks are handled, guard selection is
  improved to handle long-term guards better, pluggable transports
  should work a bit better, and some annoying hidden service performance
  bugs should be addressed.

  o New compiler and system requirements:
    - Tor 0.2.6.x requires that your compiler support more of the C99
      language standard than before. The 'configure' script now detects
      whether your compiler supports C99 mid-block declarations and
      designated initializers. If it does not, Tor will not compile.

      We may revisit this requirement if it turns out that a significant
      number of people need to build Tor with compilers that don't
      bother implementing a 15-year-old standard. Closes ticket 13233.
    - Tor no longer supports systems without threading support. When we
      began working on Tor, there were several systems that didn't have
      threads, or where the thread support wasn't able to run the
      threads of a single process on multiple CPUs. That no longer
      holds: every system where Tor needs to run well now has threading
      support. Resolves ticket 12439.

  o Deprecated versions and removed support:
    - Tor relays older than 0.2.4.18-rc are no longer allowed to
      advertise themselves on the network. Closes ticket 13555.
    - Tor clients no longer support connecting to hidden services
      running on Tor 0.2.2.x and earlier; the Support022HiddenServices
      option has been removed. (There shouldn't be any hidden services
      running these versions on the network.) Closes ticket 7803.

  o Directory authority changes:
    - The directory authority Faravahar has a new IP address. This
      closes ticket 14487.
    - Remove turtles as a directory authority.
    - Add longclaw as a new (v3) directory authority. This implements
      ticket 13296. This keeps the directory authority count at 9.

  o Major features (bridges):
    - Expose the outgoing upstream HTTP/SOCKS proxy to pluggable
      transports if they are configured via the "TOR_PT_PROXY"
      environment variable. Implements proposal 232. Resolves
      ticket 8402.

  o Major features (changed defaults):
    - Prevent relay operators from unintentionally running exits: When a
      relay is configured as an exit node, we now warn the user unless
      the "ExitRelay" option is set to 1. We warn even more loudly if
      the relay is configured with the default exit policy, since this
      can indicate accidental misconfiguration. Setting "ExitRelay 0"
      stops Tor from running as an exit relay. Closes ticket 10067.

  o Major features (client performance, hidden services):
    - Allow clients to use optimistic data when connecting to a hidden
      service, which should remove a round-trip from hidden service
      initialization. See proposal 181 for details. Implements
      ticket 13211.

  o Major features (directory system):
    - Upon receiving an unparseable directory object, if its digest
      matches what we expected, then don't try to download it again.
      Previously, when we got a descriptor we didn't like, we would keep
      trying to download it over and over. Closes ticket 11243.
    - When downloading server- or microdescriptors from a directory
      server, we no longer launch multiple simultaneous requests to the
      same server. This reduces load on the directory servers,
      especially when directory guards are in use. Closes ticket 9969.
    - When downloading server- or microdescriptors over a tunneled
      connection, do not limit the length of our requests to what the
      Squid proxy is willing to handle. Part of ticket 9969.
    - Authorities can now vote on the correct digests and latest
      versions for different software packages. This allows packages
      that include Tor to use the Tor authority system as a way to get
      notified of updates and their correct digests. Implements proposal
      227. Closes ticket 10395.

  o Major features (guards):
    - Introduce the Guardfraction feature to improves load balancing on
      guard nodes. Specifically, it aims to reduce the traffic gap that
      guard nodes experience when they first get the Guard flag. This is
      a required step if we want to increase the guard lifetime to 9
      months or greater.  Closes ticket 9321.

  o Major features (hidden services):
    - Make HS port scanning more difficult by immediately closing the
      circuit when a user attempts to connect to a nonexistent port.
      Closes ticket 13667.
    - Add a HiddenServiceStatistics option that allows Tor relays to
      gather and publish statistics about the overall size and volume of
      hidden service usage. Specifically, when this option is turned on,
      an HSDir will publish an approximate number of hidden services
      that have published descriptors to it the past 24 hours. Also, if
      a relay has acted as a hidden service rendezvous point, it will
      publish the approximate amount of rendezvous cells it has relayed
      the past 24 hours. The statistics themselves are obfuscated so
      that the exact values cannot be derived. For more details see
      proposal 238, "Better hidden service stats from Tor relays". This
      feature is currently disabled by default. Implements feature 13192.

  o Major features (performance):
    - Make the CPU worker implementation more efficient by avoiding the
      kernel and lengthening pipelines. The original implementation used
      sockets to transfer data from the main thread to the workers, and
      didn't allow any thread to be assigned more than a single piece of
      work at once. The new implementation avoids communications
      overhead by making requests in shared memory, avoiding kernel IO
      where possible, and keeping more requests in flight at once.
      Implements ticket 9682.

  o Major features (relay):
    - Raise the minimum acceptable configured bandwidth rate for bridges
      to 50 KiB/sec and for relays to 75 KiB/sec. (The old values were
      20 KiB/sec.) Closes ticket 13822.
    - Complete revision of the code that relays use to decide which cell
      to send next. Formerly, we selected the best circuit to write on
      each channel, but we didn't select among channels in any
      sophisticated way. Now, we choose the best circuits globally from
      among those whose channels are ready to deliver traffic.

      This patch implements a new inter-cmux comparison API, a global
      high/low watermark mechanism and a global scheduler loop for
      transmission prioritization across all channels as well as among
      circuits on one channel. This schedule is currently tuned to
      (tolerantly) avoid making changes in network performance, but it
      should form the basis for major circuit performance increases in
      the future. Code by Andrea; tuning by Rob Jansen; implements
      ticket 9262.

  o Major features (sample torrc):
    - Add a new, infrequently-changed "torrc.minimal". This file is
      similar to torrc.sample, but it will change as infrequently as
      possible, for the benefit of users whose systems prompt them for
      intervention whenever a default configuration file is changed.
      Making this change allows us to update torrc.sample to be a more
      generally useful "sample torrc".

  o Major features (security, unix domain sockets):
    - Allow SocksPort to be an AF_UNIX Unix Domain Socket. Now high risk
      applications can reach Tor without having to create AF_INET or
      AF_INET6 sockets, meaning they can completely disable their
      ability to make non-Tor network connections. To create a socket of
      this type, use "SocksPort unix:/path/to/socket". Implements
      ticket 12585.
    - Support mapping hidden service virtual ports to AF_UNIX sockets.
      The syntax is "HiddenServicePort 80 unix:/path/to/socket".
      Implements ticket 11485.

  o Major bugfixes (client, automap):
    - Repair automapping with IPv6 addresses. This automapping should
      have worked previously, but one piece of debugging code that we
      inserted to detect a regression actually caused the regression to
      manifest itself again. Fixes bug 13811 and bug 12831; bugfix on
      0.2.4.7-alpha. Diagnosed and fixed by Francisco Blas
      Izquierdo Riera.

  o Major bugfixes (crash, OSX, security):
    - Fix a remote denial-of-service opportunity caused by a bug in
      OSX's _strlcat_chk() function. Fixes bug 15205; bug first appeared
      in OSX 10.9.

  o Major bugfixes (directory authorities):
    - Do not assign the HSDir flag to relays if they are not Valid, or
      currently hibernating. Fixes 12573; bugfix on 0.2.0.10-alpha.

  o Major bugfixes (directory bandwidth performance):
    - Don't flush the zlib buffer aggressively when compressing
      directory information for clients. This should save about 7% of
      the bandwidth currently used for compressed descriptors and
      microdescriptors. Fixes bug 11787; bugfix on 0.1.1.23.

  o Major bugfixes (exit node stability):
    - Fix an assertion failure that could occur under high DNS load.
      Fixes bug 14129; bugfix on Tor 0.0.7rc1. Found by "jowr";
      diagnosed and fixed by "cypherpunks".

  o Major bugfixes (FreeBSD IPFW transparent proxy):
    - Fix address detection with FreeBSD transparent proxies, when
      "TransProxyType ipfw" is in use. Fixes bug 15064; bugfix
      on 0.2.5.4-alpha.

  o Major bugfixes (hidden services):
    - When closing an introduction circuit that was opened in parallel
      with others, don't mark the introduction point as unreachable.
      Previously, the first successful connection to an introduction
      point would make the other introduction points get marked as
      having timed out. Fixes bug 13698; bugfix on 0.0.6rc2.

  o Major bugfixes (Linux seccomp2 sandbox):
    - Upon receiving sighup with the seccomp2 sandbox enabled, do not
      crash during attempts to call wait4. Fixes bug 15088; bugfix on
      0.2.5.1-alpha. Patch from "sanic".

  o Major bugfixes (mixed relay-client operation):
    - When running as a relay and client at the same time (not
      recommended), if we decide not to use a new guard because we want
      to retry older guards, only close the locally-originating circuits
      passing through that guard. Previously we would close all the
      circuits through that guard. Fixes bug 9819; bugfix on
      0.2.1.1-alpha. Reported by "skruffy".

  o Major bugfixes (pluggable transports):
    - Initialize the extended OR Port authentication cookie before
      launching pluggable transports. This prevents a race condition
      that occured when server-side pluggable transports would cache the
      authentication cookie before it has been (re)generated. Fixes bug
      15240; bugfix on 0.2.5.1-alpha.

  o Major bugfixes (relay, stability, possible security):
    - Fix a bug that could lead to a relay crashing with an assertion
      failure if a buffer of exactly the wrong layout is passed to
      buf_pullup() at exactly the wrong time. Fixes bug 15083; bugfix on
      0.2.0.10-alpha. Patch from "cypherpunks".
    - Do not assert if the 'data' pointer on a buffer is advanced to the
      very end of the buffer; log a BUG message instead. Only assert if
      it is past that point. Fixes bug 15083; bugfix on 0.2.0.10-alpha.

  o Minor features (build):
    - New --disable-system-torrc compile-time option to prevent Tor from
      looking for the system-wide torrc or torrc-defaults files.
      Resolves ticket 13037.

  o Minor features (client):
    - Clients are now willing to send optimistic data (before they
      receive a 'connected' cell) to relays of any version. (Relays
      without support for optimistic data are no longer supported on the
      Tor network.) Resolves ticket 13153.

  o Minor features (client):
    - Validate hostnames in SOCKS5 requests more strictly. If SafeSocks
      is enabled, reject requests with IP addresses as hostnames.
      Resolves ticket 13315.

  o Minor features (controller):
    - Add a "SIGNAL HEARTBEAT" controller command that tells Tor to
      write an unscheduled heartbeat message to the log. Implements
      feature 9503.
    - Include SOCKS_USERNAME and SOCKS_PASSWORD values in controller
      events so controllers can observe circuit isolation inputs. Closes
      ticket 8405.
    - ControlPort now supports the unix:/path/to/socket syntax as an
      alternative to the ControlSocket option, for consistency with
      SocksPort and HiddenServicePort. Closes ticket 14451.
    - New "GETINFO bw-event-cache" to get information about recent
      bandwidth events. Closes ticket 14128. Useful for controllers to
      get recent bandwidth history after the fix for ticket 13988.
    - Messages about problems in the bootstrap process now include
      information about the server we were trying to connect to when we
      noticed the problem. Closes ticket 15006.

  o Minor features (Denial of service resistance):
    - Count the total number of bytes used storing hidden service
      descriptors against the value of MaxMemInQueues. If we're low on
      memory, and more than 20% of our memory is used holding hidden
      service descriptors, free them until no more than 10% of our
      memory holds hidden service descriptors. Free the least recently
      fetched descriptors first. Resolves ticket 13806.
    - When we have recently been under memory pressure (over 3/4 of
      MaxMemInQueues is allocated), then allocate smaller zlib objects
      for small requests. Closes ticket 11791.

  o Minor features (directory authorities):
    - Don't list relays with a bandwidth estimate of 0 in the consensus.
      Implements a feature proposed during discussion of bug 13000.
    - In tor-gencert, report an error if the user provides the same
      argument more than once.
    - If a directory authority can't find a best consensus method in the
      votes that it holds, it now falls back to its favorite consensus
      method. Previously, it fell back to method 1. Neither of these is
      likely to get enough signatures, but "fall back to favorite"
      doesn't require us to maintain support an obsolete consensus
      method. Implements part of proposal 215.

  o Minor features (geoip):
    - Update geoip to the March 3 2015 Maxmind GeoLite2 Country database.
    - Update geoip6 to the March 3 2015 Maxmind GeoLite2
      Country database.

  o Minor features (guard nodes):
    - Reduce the time delay before saving guard status to disk from 10
      minutes to 30 seconds (or from one hour to 10 minutes if
      AvoidDiskWrites is set). Closes ticket 12485.

  o Minor features (heartbeat):
    - On relays, report how many connections we negotiated using each
      version of the Tor link protocols. This information will let us
      know if removing support for very old versions of the Tor
      protocols is harming the network. Closes ticket 15212.

  o Minor features (hidden service):
    - Make Sybil attacks against hidden services harder by changing the
      minimum time required to get the HSDir flag from 25 hours up to 96
      hours. Addresses ticket 14149.
    - New option "HiddenServiceAllowUnknownPorts" to allow hidden
      services to disable the anti-scanning feature introduced in
      0.2.6.2-alpha. With this option not set, a connection to an
      unlisted port closes the circuit. With this option set, only a
      RELAY_DONE cell is sent. Closes ticket 14084.
    - When re-enabling the network, don't try to build introduction
      circuits until we have successfully built a circuit. This makes
      hidden services come up faster when the network is re-enabled.
      Patch from "akwizgran". Closes ticket 13447.
    - When we fail to retrieve a hidden service descriptor, send the
      controller an "HS_DESC FAILED" controller event. Implements
      feature 13212.
    - New HiddenServiceDirGroupReadable option to cause hidden service
      directories and hostname files to be created group-readable. Patch
      from "anon", David Stainton, and "meejah". Closes ticket 11291.

  o Minor features (interface):
    - Implement "-f -" command-line option to read torrc configuration
      from standard input, if you don't want to store the torrc file in
      the file system. Implements feature 13865.

  o Minor features (logging):
    - Add a count of unique clients to the bridge heartbeat message.
      Resolves ticket 6852.
    - Suppress "router info incompatible with extra info" message when
      reading extrainfo documents from cache. (This message got loud
      around when we closed bug 9812 in 0.2.6.2-alpha.) Closes
      ticket 13762.
    - Elevate hidden service authorized-client message from DEBUG to
      INFO. Closes ticket 14015.
    - On Unix-like systems, you can now use named pipes as the target of
      the Log option, and other options that try to append to files.
      Closes ticket 12061. Patch from "carlo von lynX".
    - When opening a log file at startup, send it every log message that
      we generated between startup and opening it. Previously, log
      messages that were generated before opening the log file were only
      logged to stdout. Closes ticket 6938.
    - Add a TruncateLogFile option to overwrite logs instead of
      appending to them. Closes ticket 5583.
    - Quiet some log messages in the heartbeat and at startup. Closes
      ticket 14950.

  o Minor features (portability, Solaris):
    - Threads are no longer disabled by default on Solaris; we believe
      that the versions of Solaris with broken threading support are all
      obsolete by now. Resolves ticket 9495.

  o Minor features (relay):
    - Re-check our address after we detect a changed IP address from
      getsockname(). This ensures that the controller command "GETINFO
      address" will report the correct value. Resolves ticket 11582.
      Patch from "ra".
    - A new AccountingRule option lets Relays set whether they'd like
      AccountingMax to be applied separately to inbound and outbound
      traffic, or applied to the sum of inbound and outbound traffic.
      Resolves ticket 961. Patch by "chobe".
    - When identity keypair is generated for first time, log a
      congratulatory message that links to the new relay lifecycle
      document. Implements feature 10427.

  o Minor features (security, memory wiping):
    - Ensure we securely wipe keys from memory after
      crypto_digest_get_digest and init_curve25519_keypair_from_file
      have finished using them. Resolves ticket 13477.

  o Minor features (security, out-of-memory handling):
    - When handling an out-of-memory condition, allocate less memory for
      temporary data structures. Fixes issue 10115.
    - When handling an out-of-memory condition, consider more types of
      buffers, including those on directory connections, and zlib
      buffers. Resolves ticket 11792.

  o Minor features (stability):
    - Add assertions in our hash-table iteration code to check for
      corrupted values that could cause infinite loops. Closes
      ticket 11737.

  o Minor features (systemd):
    - Various improvements and modernizations in systemd hardening
      support. Closes ticket 13805. Patch from Craig Andrews.
    - Where supported, when running with systemd, report successful
      startup to systemd. Part of ticket 11016. Patch by Michael Scherer.
    - When running with systemd, support systemd watchdog messages. Part
      of ticket 11016. Patch by Michael Scherer.

  o Minor features (testing networks):
    - Add the TestingDirAuthVoteExit option, which lists nodes to assign
      the "Exit" flag regardless of their uptime, bandwidth, or exit
      policy. TestingTorNetwork must be set for this option to have any
      effect. Previously, authorities would take up to 35 minutes to
      give nodes the Exit flag in a test network. Partially implements
      ticket 13161.
    - Drop the minimum RendPostPeriod on a testing network to 5 seconds,
      and the default on a testing network to 2 minutes. Drop the
      MIN_REND_INITIAL_POST_DELAY on a testing network to 5 seconds, but
      keep the default on a testing network at 30 seconds. This reduces
      HS bootstrap time to around 25 seconds. Also, change the default
      time in test-network.sh to match. Closes ticket 13401. Patch
      by "teor".
    - Create TestingDirAuthVoteHSDir to correspond to
      TestingDirAuthVoteExit/Guard. Ensures that authorities vote the
      HSDir flag for the listed relays regardless of uptime or ORPort
      connectivity. Respects the value of VoteOnHidServDirectoriesV2.
      Partial implementation for ticket 14067. Patch by "teor".

  o Minor features (tor2web mode):
    - Introduce the config option Tor2webRendezvousPoints, which allows
      clients in Tor2webMode to select a specific Rendezvous Point to be
      used in HS circuits. This might allow better performance for
      Tor2Web nodes. Implements ticket 12844.

  o Minor features (transparent proxy):
    - Update the transparent proxy option checks to allow for both ipfw
      and pf on OS X. Closes ticket 14002.
    - Use the correct option when using IPv6 with transparent proxy
      support on Linux. Resolves 13808. Patch by Francisco Blas
      Izquierdo Riera.

  o Minor features (validation):
    - Check all date/time values passed to tor_timegm and
      parse_rfc1123_time for validity, taking leap years into account.
      Improves HTTP header validation. Implemented with bug 13476.
    - In correct_tm(), limit the range of values returned by system
      localtime(_r) and gmtime(_r) to be between the years 1 and 8099.
      This means we don't have to deal with negative or too large dates,
      even if a clock is wrong. Otherwise we might fail to read a file
      written by us which includes such a date. Fixes bug 13476.
    - Stop allowing invalid address patterns like "*/24" that contain
      both a wildcard address and a bit prefix length. This affects all
      our address-range parsing code. Fixes bug 7484; bugfix
      on 0.0.2pre14.

  o Minor bugfixes (bridge clients):
    - When configured to use a bridge without an identity digest (not
      recommended), avoid launching an extra channel to it when
      bootstrapping. Fixes bug 7733; bugfix on 0.2.4.4-alpha.

  o Minor bugfixes (bridges):
    - When DisableNetwork is set, do not launch pluggable transport
      plugins, and if any are running, terminate them. Fixes bug 13213;
      bugfix on 0.2.3.6-alpha.

  o Minor bugfixes (C correctness):
    - Fix several instances of possible integer overflow/underflow/NaN.
      Fixes bug 13104; bugfix on 0.2.3.1-alpha and later. Patches
      from "teor".
    - In circuit_build_times_calculate_timeout() in circuitstats.c,
      avoid dividing by zero in the pareto calculations. This traps
      under clang's "undefined-trap" sanitizer. Fixes bug 13290; bugfix
      on 0.2.2.2-alpha.
    - Fix an integer overflow in format_time_interval(). Fixes bug
      13393; bugfix on 0.2.0.10-alpha.
    - Set the correct day of year value when the system's localtime(_r)
      or gmtime(_r) functions fail to set struct tm. Not externally
      visible. Fixes bug 13476; bugfix on 0.0.2pre14.
    - Avoid unlikely signed integer overflow in tor_timegm on systems
      with 32-bit time_t. Fixes bug 13476; bugfix on 0.0.2pre14.

  o Minor bugfixes (certificate handling):
    - If an authority operator accidentally makes a signing certificate
      with a future publication time, do not discard its real signing
      certificates. Fixes bug 11457; bugfix on 0.2.0.3-alpha.
    - Remove any old authority certificates that have been superseded
      for at least two days. Previously, we would keep superseded
      certificates until they expired, if they were published close in
      time to the certificate that superseded them. Fixes bug 11454;
      bugfix on 0.2.1.8-alpha.

  o Minor bugfixes (client):
    - Fix smartlist_choose_node_by_bandwidth() so that relays with the
      BadExit flag are not considered worthy candidates. Fixes bug
      13066; bugfix on 0.1.2.3-alpha.
    - Use the consensus schedule for downloading consensuses, and not
      the generic schedule. Fixes bug 11679; bugfix on 0.2.2.6-alpha.
    - Handle unsupported or malformed SOCKS5 requests properly by
      responding with the appropriate error message before closing the
      connection. Fixes bugs 12971 and 13314; bugfix on 0.0.2pre13.

  o Minor bugfixes (client, automapping):
    - Avoid crashing on torrc lines for VirtualAddrNetworkIPv[4|6] when
      no value follows the option. Fixes bug 14142; bugfix on
      0.2.4.7-alpha. Patch by "teor".
    - Fix a memory leak when using AutomapHostsOnResolve. Fixes bug
      14195; bugfix on 0.1.0.1-rc.
    - Prevent changes to other options from removing the wildcard value
      "." from "AutomapHostsSuffixes". Fixes bug 12509; bugfix
      on 0.2.0.1-alpha.
    - Allow MapAddress and AutomapHostsOnResolve to work together when
      an address is mapped into another address type (like .onion) that
      must be automapped at resolve time. Fixes bug 7555; bugfix
      on 0.2.0.1-alpha.

  o Minor bugfixes (client, bridges):
    - When we are using bridges and we had a network connectivity
      problem, only retry connecting to our currently configured
      bridges, not all bridges we know about and remember using. Fixes
      bug 14216; bugfix on 0.2.2.17-alpha.

  o Minor bugfixes (client, DNS):
    - Report the correct cached DNS expiration times on SOCKS port or in
      DNS replies. Previously, we would report everything as "never
      expires." Fixes bug 14193; bugfix on 0.2.3.17-beta.
    - Avoid a small memory leak when we find a cached answer for a
      reverse DNS lookup in a client-side DNS cache. (Remember, client-
      side DNS caching is off by default, and is not recommended.) Fixes
      bug 14259; bugfix on 0.2.0.1-alpha.

  o Minor bugfixes (client, IPv6):
    - Reject socks requests to literal IPv6 addresses when IPv6Traffic
      flag is not set; and not because the NoIPv4Traffic flag was set.
      Previously we'd looked at the NoIPv4Traffic flag for both types of
      literal addresses. Fixes bug 14280; bugfix on 0.2.4.7-alpha.

  o Minor bugfixes (client, microdescriptors):
    - Use a full 256 bits of the SHA256 digest of a microdescriptor when
      computing which microdescriptors to download. This keeps us from
      erroneous download behavior if two microdescriptor digests ever
      have the same first 160 bits. Fixes part of bug 13399; bugfix
      on 0.2.3.1-alpha.
    - Reset a router's status if its microdescriptor digest changes,
      even if the first 160 bits remain the same. Fixes part of bug
      13399; bugfix on 0.2.3.1-alpha.

  o Minor bugfixes (client, torrc):
    - Stop modifying the value of our DirReqStatistics torrc option just
      because we're not a bridge or relay. This bug was causing Tor
      Browser users to write "DirReqStatistics 0" in their torrc files
      as if they had chosen to change the config. Fixes bug 4244; bugfix
      on 0.2.3.1-alpha.
    - When GeoIPExcludeUnknown is enabled, do not incorrectly decide
      that our options have changed every time we SIGHUP. Fixes bug
      9801; bugfix on 0.2.4.10-alpha. Patch from "qwerty1".

  o Minor bugfixes (compilation):
    - Fix a compilation warning on s390. Fixes bug 14988; bugfix
      on 0.2.5.2-alpha.
    - Silence clang warnings under --enable-expensive-hardening,
      including implicit truncation of 64 bit values to 32 bit, const
      char assignment to self, tautological compare, and additional
      parentheses around equality tests. Fixes bug 13577; bugfix
      on 0.2.5.4-alpha.
    - Fix a clang warning about checking whether an address in the
      middle of a structure is NULL. Fixes bug 14001; bugfix
      on 0.2.1.2-alpha.
    - The address of an array in the middle of a structure will always
      be non-NULL. clang recognises this and complains. Disable the
      tautologous and redundant check to silence this warning. Fixes bug
      14001; bugfix on 0.2.1.2-alpha.
    - Compile correctly with (unreleased) OpenSSL 1.1.0 headers.
      Addresses ticket 14188.
    - Build without warnings with the stock OpenSSL srtp.h header, which
      has a duplicate declaration of SSL_get_selected_srtp_profile().
      Fixes bug 14220; this is OpenSSL's bug, not ours.
    - Do not compile any code related to Tor2Web mode when Tor2Web mode
      is not enabled at compile time. Previously, this code was included
      in a disabled state. See discussion on ticket 12844.
    - Allow our configure script to build correctly with autoconf 2.62
      again. Fixes bug 12693; bugfix on 0.2.5.2-alpha.
    - Improve the error message from ./configure to make it clear that
      when asciidoc has not been found, the user will have to either add
      --disable-asciidoc argument or install asciidoc. Resolves
      ticket 13228.

  o Minor bugfixes (controller):
    - Report "down" in response to the "GETINFO entry-guards" command
      when relays are down with an unreachable_since value. Previously,
      we would report "up". Fixes bug 14184; bugfix on 0.1.2.2-alpha.
    - Avoid crashing on a malformed EXTENDCIRCUIT command. Fixes bug
      14116; bugfix on 0.2.2.9-alpha.

  o Minor bugfixes (controller):
    - Return an error when the second or later arguments of the
      "setevents" controller command are invalid events. Previously we
      would return success while silently skipping invalid events. Fixes
      bug 13205; bugfix on 0.2.3.2-alpha. Reported by "fpxnns".

  o Minor bugfixes (directory authority):
    - Allow directory authorities to fetch more data from one another if
      they find themselves missing lots of votes. Previously, they had
      been bumping against the 10 MB queued data limit. Fixes bug 14261;
      bugfix on 0.1.2.5-alpha.
    - Do not attempt to download extrainfo documents which we will be
      unable to validate with a matching server descriptor. Fixes bug
      13762; bugfix on 0.2.0.1-alpha.
    - Fix a bug that was truncating AUTHDIR_NEWDESC events sent to the
      control port. Fixes bug 14953; bugfix on 0.2.0.1-alpha.
    - Enlarge the buffer to read bwauth generated files to avoid an
      issue when parsing the file in dirserv_read_measured_bandwidths().
      Fixes bug 14125; bugfix on 0.2.2.1-alpha.
    - When running as a v3 directory authority, advertise that you serve
      extra-info documents so that clients who want them can find them
      from you too. Fixes part of bug 11683; bugfix on 0.2.0.1-alpha.

  o Minor bugfixes (directory system):
    - Always believe that v3 directory authorities serve extra-info
      documents, whether they advertise "caches-extra-info" or not.
      Fixes part of bug 11683; bugfix on 0.2.0.1-alpha.
    - Check the BRIDGE_DIRINFO flag bitwise rather than using equality.
      Previously, directories offering BRIDGE_DIRINFO and some other
      flag (i.e. microdescriptors or extrainfo) would be ignored when
      looking for bridges. Partially fixes bug 13163; bugfix
      on 0.2.0.7-alpha.

  o Minor bugfixes (file handling):
    - Stop failing when key files are zero-length. Instead, generate new
      keys, and overwrite the empty key files. Fixes bug 13111; bugfix
      on all versions of Tor. Patch by "teor".
    - Stop generating a fresh .old RSA onion key file when the .old file
      is missing. Fixes part of 13111; bugfix on 0.0.6rc1.
    - Avoid overwriting .old key files with empty key files.
    - Skip loading zero-length extrainfo store, router store, stats,
      state, and key files.
    - Avoid crashing when trying to reload a torrc specified as a
      relative path with RunAsDaemon turned on. Fixes bug 13397; bugfix
      on 0.2.3.11-alpha.

  o Minor bugfixes (hidden services):
    - Close the introduction circuit when we have no more usable intro
      points, instead of waiting for it to time out. This also ensures
      that no follow-up HS descriptor fetch is triggered when the
      circuit eventually times out. Fixes bug 14224; bugfix on 0.0.6.
    - When fetching a hidden service descriptor for a down service that
      was recently up, do not keep refetching until we try the same
      replica twice in a row. Fixes bug 14219; bugfix on 0.2.0.10-alpha.
    - Correctly send a controller event when we find that a rendezvous
      circuit has finished. Fixes bug 13936; bugfix on 0.1.1.5-alpha.
    - Pre-check directory permissions for new hidden-services to avoid
      at least one case of "Bug: Acting on config options left us in a
      broken state. Dying." Fixes bug 13942; bugfix on 0.0.6pre1.
    - When fetching hidden service descriptors, we now check not only
      for whether we got the hidden service we had in mind, but also
      whether we got the particular descriptors we wanted. This prevents
      a class of inefficient but annoying DoS attacks by hidden service
      directories. Fixes bug 13214; bugfix on 0.2.1.6-alpha. Reported
      by "special".

  o Minor bugfixes (Linux seccomp2 sandbox):
    - Make transparent proxy support work along with the seccomp2
      sandbox. Fixes part of bug 13808; bugfix on 0.2.5.1-alpha. Patch
      by Francisco Blas Izquierdo Riera.
    - Fix a memory leak in tor-resolve when running with the sandbox
      enabled. Fixes bug 14050; bugfix on 0.2.5.9-rc.
    - Allow glibc fatal errors to be sent to stderr before Tor exits.
      Previously, glibc would try to write them to /dev/tty, and the
      sandbox would trap the call and make Tor exit prematurely. Fixes
      bug 14759; bugfix on 0.2.5.1-alpha.

  o Minor bugfixes (logging):
    - Avoid crashing when there are more log domains than entries in
      domain_list. Bugfix on 0.2.3.1-alpha.
    - Downgrade warnings about RSA signature failures to info log level.
      Emit a warning when an extra info document is found incompatible
      with a corresponding router descriptor. Fixes bug 9812; bugfix
      on 0.0.6rc3.
    - Make connection_ap_handshake_attach_circuit() log the circuit ID
      correctly. Fixes bug 13701; bugfix on 0.0.6.

  o Minor bugfixes (networking):
    - Check for orconns and use connection_or_close_for_error() rather
      than connection_mark_for_close() directly in the getsockopt()
      failure case of connection_handle_write_impl(). Fixes bug 11302;
      bugfix on 0.2.4.4-alpha.

  o Minor bugfixes (parsing):
    - Stop accepting milliseconds (or other junk) at the end of
      descriptor publication times. Fixes bug 9286; bugfix on 0.0.2pre25.
    - Support two-number and three-number version numbers correctly, in
      case we change the Tor versioning system in the future. Fixes bug
      13661; bugfix on 0.0.8pre1.

  o Minor bugfixes (portability):
    - Fix the ioctl()-based network interface lookup code so that it
      will work on systems that have variable-length struct ifreq, for
      example Mac OS X.
    - Use the correct datatype in the SipHash-2-4 function to prevent
      compilers from assuming any sort of alignment. Fixes bug 15436;
      bugfix on 0.2.5.3-alpha.

  o Minor bugfixes (preventative security, C safety):
    - When reading a hexadecimal, base-32, or base-64 encoded value from
      a string, always overwrite the whole output buffer. This prevents
      some bugs where we would look at (but fortunately, not reveal)
      uninitialized memory on the stack. Fixes bug 14013; bugfix on all
      versions of Tor.
    - Clear all memory targetted by tor_addr_{to,from}_sockaddr(), not
      just the part that's used. This makes it harder for data leak bugs
      to occur in the event of other programming failures. Resolves
      ticket 14041.

  o Minor bugfixes (relay):
    - When generating our family list, remove spaces from around the
      entries. Fixes bug 12728; bugfix on 0.2.1.7-alpha.
    - If our previous bandwidth estimate was 0 bytes, allow publishing a
      new relay descriptor immediately. Fixes bug 13000; bugfix
      on 0.1.1.6-alpha.

  o Minor bugfixes (shutdown):
    - When shutting down, always call event_del() on lingering read or
      write events before freeing them. Otherwise, we risk double-frees
      or read-after-frees in event_base_free(). Fixes bug 12985; bugfix
      on 0.1.0.2-rc.

  o Minor bugfixes (small memory leaks):
    - Avoid leaking memory when using IPv6 virtual address mappings.
      Fixes bug 14123; bugfix on 0.2.4.7-alpha. Patch by Tom van
      der Woerdt.

  o Minor bugfixes (statistics):
    - Increase period over which bandwidth observations are aggregated
      from 15 minutes to 4 hours. Fixes bug 13988; bugfix on 0.0.8pre1.

  o Minor bugfixes (systemd support):
    - Run correctly under systemd with the RunAsDaemon option set. Fixes
      part of bug 14141; bugfix on 0.2.5.7-rc. Patch from Tomasz Torcz.
    - Inform the systemd supervisor about more changes in the Tor
      process status. Implements part of ticket 14141. Patch from
      Tomasz Torcz.

  o Minor bugfixes (testing networks):
    - Fix TestingDirAuthVoteGuard to properly give out Guard flags in a
      testing network. Fixes bug 13064; bugfix on 0.2.5.2-alpha.
    - Stop using the default authorities in networks which provide both
      AlternateDirAuthority and AlternateBridgeAuthority. Partially
      fixes bug 13163; bugfix on 0.2.0.13-alpha.

  o Minor bugfixes (testing networks, fast startup):
    - Allow Tor to build circuits using a consensus with no exits. If
      the consensus has no exits (typical of a bootstrapping test
      network), allow Tor to build circuits once enough descriptors have
      been downloaded. This assists in bootstrapping a testing Tor
      network. Fixes bug 13718; bugfix on 0.2.4.10-alpha. Patch
      by "teor".
    - When V3AuthVotingInterval is low, give a lower If-Modified-Since
      header to directory servers. This allows us to obtain consensuses
      promptly when the consensus interval is very short. This assists
      in bootstrapping a testing Tor network. Fixes parts of bugs 13718
      and 13963; bugfix on 0.2.0.3-alpha. Patch by "teor".
    - Stop assuming that private addresses are local when checking
      reachability in a TestingTorNetwork. Instead, when testing, assume
      all OR connections are remote. (This is necessary due to many test
      scenarios running all relays on localhost.) This assists in
      bootstrapping a testing Tor network. Fixes bug 13924; bugfix on
      0.1.0.1-rc. Patch by "teor".
    - Avoid building exit circuits from a consensus with no exits. Now
      thanks to our fix for 13718, we accept a no-exit network as not
      wholly lost, but we need to remember not to try to build exit
      circuits on it. Closes ticket 13814; patch by "teor".
    - Stop requiring exits to have non-zero bandwithcapacity in a
      TestingTorNetwork. Instead, when TestingMinExitFlagThreshold is 0,
      ignore exit bandwidthcapacity. This assists in bootstrapping a
      testing Tor network. Fixes parts of bugs 13718 and 13839; bugfix
      on 0.2.0.3-alpha. Patch by "teor".
    - Add "internal" to some bootstrap statuses when no exits are
      available. If the consensus does not contain Exits, Tor will only
      build internal circuits. In this case, relevant statuses will
      contain the word "internal" as indicated in the Tor control-
       spec.txt. When bootstrap completes, Tor will be ready to build
      internal circuits. If a future consensus contains Exits, exit
      circuits may become available. Fixes part of bug 13718; bugfix on
      0.2.4.10-alpha. Patch by "teor".
    - Decrease minimum consensus interval to 10 seconds when
      TestingTorNetwork is set, or 5 seconds for the first consensus.
      Fix assumptions throughout the code that assume larger intervals.
      Fixes bugs 13718 and 13823; bugfix on 0.2.0.3-alpha. Patch
      by "teor".
    - Avoid excluding guards from path building in minimal test
      networks, when we're in a test network and excluding guards would
      exclude all relays. This typically occurs in incredibly small tor
      networks, and those using "TestingAuthVoteGuard *". Fixes part of
      bug 13718; bugfix on 0.1.1.11-alpha. Patch by "teor".

  o Minor bugfixes (testing):
    - Avoid a side-effect in a tor_assert() in the unit tests. Fixes bug
      15188; bugfix on 0.1.2.3-alpha. Patch from Tom van der Woerdt.
    - Stop spawn test failures due to a race condition between the
      SIGCHLD handler updating the process status, and the test reading
      it. Fixes bug 13291; bugfix on 0.2.3.3-alpha.
    - Avoid passing an extra backslash when creating a temporary
      directory for running the unit tests on Windows. Fixes bug 12392;
      bugfix on 0.2.2.25-alpha. Patch from Gisle Vanem.

  o Minor bugfixes (TLS):
    - Check more thoroughly throughout the TLS code for possible
      unlogged TLS errors. Possible diagnostic or fix for bug 13319.

  o Minor bugfixes (transparent proxy):
    - Use getsockname, not getsockopt, to retrieve the address for a
      TPROXY-redirected connection. Fixes bug 13796; bugfix
      on 0.2.5.2-alpha.

  o Minor bugfixes (windows):
    - Remove code to special-case handling of NTE_BAD_KEYSET when
      acquiring windows CryptoAPI context. This error can't actually
      occur for the parameters we're providing. Fixes bug 10816; bugfix
      on 0.0.2pre26.

  o Minor bugfixes (zlib):
    - Avoid truncating a zlib stream when trying to finalize it with an
      empty output buffer. Fixes bug 11824; bugfix on 0.1.1.23.

  o Code simplification and refactoring:
    - Change the entry_is_live() function to take named bitfield
      elements instead of an unnamed list of booleans. Closes
      ticket 12202.
    - Refactor and unit-test entry_is_time_to_retry() in entrynodes.c.
      Resolves ticket 12205.
    - Use calloc and reallocarray functions instead of multiply-
      then-malloc. This makes it less likely for us to fall victim to an
      integer overflow attack when allocating. Resolves ticket 12855.
    - Use the standard macro name SIZE_MAX, instead of our
      own SIZE_T_MAX.
    - Document usage of the NO_DIRINFO and ALL_DIRINFO flags clearly in
      functions which take them as arguments. Replace 0 with NO_DIRINFO
      in a function call for clarity. Seeks to prevent future issues
      like 13163.
    - Avoid 4 null pointer errors under clang static analysis by using
      tor_assert() to prove that the pointers aren't null. Fixes
      bug 13284.
    - Rework the API of policies_parse_exit_policy() to use a bitmask to
      represent parsing options, instead of a confusing mess of
      booleans. Resolves ticket 8197.
    - Introduce a helper function to parse ExitPolicy in
      or_options_t structure.
    - Move fields related to isolating and configuring client ports into
      a shared structure. Previously, they were duplicated across
      port_cfg_t, listener_connection_t, and edge_connection_t. Failure
      to copy them correctly had been the cause of at least one bug in
      the past. Closes ticket 8546.
    - Refactor the get_interface_addresses_raw() doom-function into
      multiple smaller and simpler subfunctions. Cover the resulting
      subfunctions with unit-tests. Fixes a significant portion of
      issue 12376.
    - Remove workaround in dirserv_thinks_router_is_hs_dir() that was
      only for version <= 0.2.2.24 which is now deprecated. Closes
      ticket 14202.
    - Remove a test for a long-defunct broken version-one
      directory server.
    - Refactor main loop to extract the 'loop' part. This makes it
      easier to run Tor under Shadow. Closes ticket 15176.
    - Stop using can_complete_circuits as a global variable; access it
      with a function instead.
    - Avoid using operators directly as macro arguments: this lets us
      apply coccinelle transformations to our codebase more directly.
      Closes ticket 13172.
    - Combine the functions used to parse ClientTransportPlugin and
      ServerTransportPlugin into a single function. Closes ticket 6456.
    - Add inline functions and convenience macros for inspecting channel
      state. Refactor the code to use convenience macros instead of
      checking channel state directly. Fixes issue 7356.
    - Document all members of was_router_added_t and rename
      ROUTER_WAS_NOT_NEW to ROUTER_IS_ALREADY_KNOWN to make it less
      confusable with ROUTER_WAS_TOO_OLD. Fixes issue 13644.
    - In connection_exit_begin_conn(), use END_CIRC_REASON_TORPROTOCOL
      constant instead of hardcoded value. Fixes issue 13840.
    - Refactor our generic strmap and digestmap types into a single
      implementation, so that we can add a new digest256map
      type trivially.

  o Documentation:
    - Add a doc/TUNING document with tips for handling large numbers of
      TCP connections when running busy Tor relay. Update the warning
      message to point to this file when running out of sockets
      operating system is allowing to use simultaneously. Resolves
      ticket 9708.
    - Adding section on OpenBSD to our TUNING document. Thanks to mmcc
      for writing the OpenBSD-specific tips. Resolves ticket 13702.
    - Make the tor-resolve documentation match its help string and its
      options. Resolves part of ticket 14325.
    - Log a more useful error message from tor-resolve when failing to
      look up a hidden service address. Resolves part of ticket 14325.
    - Document the bridge-authority-only 'networkstatus-bridges' file.
      Closes ticket 13713; patch from "tom".
    - Fix typo in PredictedPortsRelevanceTime option description in
      manpage. Resolves issue 13707.
    - Stop suggesting that users specify relays by nickname: it isn't a
      good idea. Also, properly cross-reference how to specify relays in
      all parts of manual documenting options that take a list of
      relays. Closes ticket 13381.
    - Clarify the HiddenServiceDir option description in manpage to make
      it clear that relative paths are taken with respect to the current
      working directory. Also clarify that this behavior is not
      guaranteed to remain indefinitely. Fixes issue 13913.

  o Distribution (systemd):
    - systemd unit file: only allow tor to write to /var/lib/tor and
      /var/log/tor. The rest of the filesystem is accessible for reading
      only. Patch by intrigeri; resolves ticket 12751.
    - systemd unit file: ensure that the process and all its children
      can never gain new privileges. Patch by intrigeri; resolves
      ticket 12939.
    - systemd unit file: set up /var/run/tor as writable for the Tor
      service. Patch by intrigeri; resolves ticket 13196.

  o Downgraded warnings:
    - Don't warn when we've attempted to contact a relay using the wrong
      ntor onion key. Closes ticket 9635.

  o Removed code:
    - Remove some lingering dead code that once supported mempools.
      Mempools were disabled by default in 0.2.5, and removed entirely
      in 0.2.6.3-alpha. Closes more of ticket 14848; patch
      by "cypherpunks".

  o Removed features (directory authorities):
    - Remove code that prevented authorities from listing Tor relays
      affected by CVE-2011-2769 as guards. These relays are already
      rejected altogether due to the minimum version requirement of
      0.2.3.16-alpha. Closes ticket 13152.
    - The "AuthDirRejectUnlisted" option no longer has any effect, as
      the fingerprints file (approved-routers) has been deprecated.
    - Directory authorities do not support being Naming dirauths anymore.
      The "NamingAuthoritativeDir" config option is now obsolete.
    - Directory authorities do not support giving out the BadDirectory
      flag anymore.
    - Directory authorities no longer advertise or support consensus
      methods 1 through 12 inclusive. These consensus methods were
      obsolete and/or insecure: maintaining the ability to support them
      served no good purpose. Implements part of proposal 215; closes
      ticket 10163.

  o Removed features:
    - To avoid confusion with the "ExitRelay" option, "ExitNode" is no
      longer silently accepted as an alias for "ExitNodes".
    - The --enable-mempool and --enable-buf-freelists options, which
      were originally created to work around bad malloc implementations,
      no longer exist. They were off-by-default in 0.2.5. Closes
      ticket 14848.
    - We no longer remind the user about configuration options that have
      been obsolete since 0.2.3.x or earlier. Patch by Adrien Bak.
    - Remove our old, non-weighted bandwidth-based node selection code.
      Previously, we used it as a fallback when we couldn't perform
      weighted bandwidth-based node selection. But that would only
      happen in the cases where we had no consensus, or when we had a
      consensus generated by buggy or ancient directory authorities. In
      either case, it's better to use the more modern, better maintained
      algorithm, with reasonable defaults for the weights. Closes
      ticket 13126.
    - Remove the --disable-curve25519 configure option. Relays and
      clients now are required to support curve25519 and the
      ntor handshake.
    - The old "StrictEntryNodes" and "StrictExitNodes" options, which
      used to be deprecated synonyms for "StrictNodes", are now marked
      obsolete. Resolves ticket 12226.
    - Clients don't understand the BadDirectory flag in the consensus
      anymore, and ignore it.

  o Removed platform support:
    - We no longer include special code to build on Windows CE; as far
      as we know, nobody has used Tor on Windows CE in a very long time.
      Closes ticket 11446.

  o Testing (test-network.sh):
    - Stop using "echo -n", as some shells' built-in echo doesn't
      support "-n". Instead, use "/bin/echo -n". Partially fixes
      bug 13161.
    - Stop an apparent test-network hang when used with make -j2. Fixes
      bug 13331.
    - Add a --delay option to test-network.sh, which configures the
      delay before the chutney network tests for data transmission.
      Partially implements ticket 13161.

  o Testing:
    - Test that tor does not fail when key files are zero-length. Check
      that tor generates new keys, and overwrites the empty key files.
    - Test that tor generates new keys when keys are missing
      (existing behavior).
    - Test that tor does not overwrite key files that already contain
      data (existing behavior). Tests bug 13111. Patch by "teor".
    - New "make test-stem" target to run stem integration tests.
      Requires that the "STEM_SOURCE_DIR" environment variable be set.
      Closes ticket 14107.
    - Make the test_cmdline_args.py script work correctly on Windows.
      Patch from Gisle Vanem.
    - Move the slower unit tests into a new "./src/test/test-slow"
      binary that can be run independently of the other tests. Closes
      ticket 13243.
    - New tests for many parts of channel, relay, and circuitmux
      functionality. Code by Andrea; part of 9262.
    - New tests for parse_transport_line(). Part of ticket 6456.
    - In the unit tests, use chgrp() to change the group of the unit
      test temporary directory to the current user, so that the sticky
      bit doesn't interfere with tests that check directory groups.
      Closes 13678.
    - Add unit tests for resolve_my_addr(). Part of ticket 12376; patch
      by 'rl1987'.
    - Refactor the function that chooses guard nodes so that it can more
      easily be tested; write some tests for it.
    - Fix and re-enable the fgets_eagain unit test. Fixes bug 12503;
      bugfix on 0.2.3.1-alpha. Patch from "cypherpunks."
    - Create unit tests for format_time_interval(). With bug 13393.
    - Add unit tests for tor_timegm signed overflow, tor_timegm and
      parse_rfc1123_time validity checks, correct_tm year clamping. Unit
      tests (visible) fixes in bug 13476.
    - Add a "coverage-html" make target to generate HTML-visualized
      coverage results when building with --enable-coverage. (Requires
      lcov.) Patch from Kevin Murray.
    - Enable the backtrace handler (where supported) when running the
      unit tests.
    - Revise all unit tests that used the legacy test_* macros to
      instead use the recommended tt_* macros. This patch was generated
      with coccinelle, to avoid manual errors. Closes ticket 13119.

Changes in version 0.2.5.11 - 2015-03-17
  Tor 0.2.5.11 is the second stable release in the 0.2.5 series.

  It backports several bugfixes from the 0.2.6 branch, including a
  couple of medium-level security fixes for relays and exit nodes.
  It also updates the list of directory authorities.

  o Directory authority changes:
    - Remove turtles as a directory authority.
    - Add longclaw as a new (v3) directory authority. This implements
      ticket 13296. This keeps the directory authority count at 9.
    - The directory authority Faravahar has a new IP address. This
      closes ticket 14487.

  o Major bugfixes (crash, OSX, security):
    - Fix a remote denial-of-service opportunity caused by a bug in
      OSX's _strlcat_chk() function. Fixes bug 15205; bug first appeared
      in OSX 10.9.

  o Major bugfixes (relay, stability, possible security):
    - Fix a bug that could lead to a relay crashing with an assertion
      failure if a buffer of exactly the wrong layout was passed to
      buf_pullup() at exactly the wrong time. Fixes bug 15083; bugfix on
      0.2.0.10-alpha. Patch from 'cypherpunks'.
    - Do not assert if the 'data' pointer on a buffer is advanced to the
      very end of the buffer; log a BUG message instead. Only assert if
      it is past that point. Fixes bug 15083; bugfix on 0.2.0.10-alpha.

  o Major bugfixes (exit node stability):
    - Fix an assertion failure that could occur under high DNS load.
      Fixes bug 14129; bugfix on Tor 0.0.7rc1. Found by "jowr";
      diagnosed and fixed by "cypherpunks".

  o Major bugfixes (Linux seccomp2 sandbox):
    - Upon receiving sighup with the seccomp2 sandbox enabled, do not
      crash during attempts to call wait4. Fixes bug 15088; bugfix on
      0.2.5.1-alpha. Patch from "sanic".

  o Minor features (controller):
    - New "GETINFO bw-event-cache" to get information about recent
      bandwidth events. Closes ticket 14128. Useful for controllers to
      get recent bandwidth history after the fix for ticket 13988.

  o Minor features (geoip):
    - Update geoip to the March 3 2015 Maxmind GeoLite2 Country database.
    - Update geoip6 to the March 3 2015 Maxmind GeoLite2
      Country database.

  o Minor bugfixes (client, automapping):
    - Avoid crashing on torrc lines for VirtualAddrNetworkIPv[4|6] when
      no value follows the option. Fixes bug 14142; bugfix on
      0.2.4.7-alpha. Patch by "teor".
    - Fix a memory leak when using AutomapHostsOnResolve. Fixes bug
      14195; bugfix on 0.1.0.1-rc.

  o Minor bugfixes (compilation):
    - Build without warnings with the stock OpenSSL srtp.h header, which
      has a duplicate declaration of SSL_get_selected_srtp_profile().
      Fixes bug 14220; this is OpenSSL's bug, not ours.

  o Minor bugfixes (directory authority):
    - Allow directory authorities to fetch more data from one another if
      they find themselves missing lots of votes. Previously, they had
      been bumping against the 10 MB queued data limit. Fixes bug 14261;
      bugfix on 0.1.2.5-alpha.
    - Enlarge the buffer to read bwauth generated files to avoid an
      issue when parsing the file in dirserv_read_measured_bandwidths().
      Fixes bug 14125; bugfix on 0.2.2.1-alpha.

  o Minor bugfixes (statistics):
    - Increase period over which bandwidth observations are aggregated
      from 15 minutes to 4 hours. Fixes bug 13988; bugfix on 0.0.8pre1.

  o Minor bugfixes (preventative security, C safety):
    - When reading a hexadecimal, base-32, or base-64 encoded value from
      a string, always overwrite the whole output buffer. This prevents
      some bugs where we would look at (but fortunately, not reveal)
      uninitialized memory on the stack. Fixes bug 14013; bugfix on all
      versions of Tor.


Changes in version 0.2.4.26 - 2015-03-17
  Tor 0.2.4.26 includes an updated list of directory authorities.  It
  also backports a couple of stability and security bugfixes from 0.2.5
  and beyond.

  o Directory authority changes:
    - Remove turtles as a directory authority.
    - Add longclaw as a new (v3) directory authority. This implements
      ticket 13296. This keeps the directory authority count at 9.
    - The directory authority Faravahar has a new IP address. This
      closes ticket 14487.

  o Major bugfixes (exit node stability, also in 0.2.6.3-alpha):
    - Fix an assertion failure that could occur under high DNS load.
      Fixes bug 14129; bugfix on Tor 0.0.7rc1. Found by "jowr";
      diagnosed and fixed by "cypherpunks".

  o Major bugfixes (relay, stability, possible security, also in 0.2.6.4-rc):
    - Fix a bug that could lead to a relay crashing with an assertion
      failure if a buffer of exactly the wrong layout was passed to
      buf_pullup() at exactly the wrong time. Fixes bug 15083; bugfix on
      0.2.0.10-alpha. Patch from 'cypherpunks'.
    - Do not assert if the 'data' pointer on a buffer is advanced to the
      very end of the buffer; log a BUG message instead. Only assert if
      it is past that point. Fixes bug 15083; bugfix on 0.2.0.10-alpha.

  o Minor features (geoip):
    - Update geoip to the March 3 2015 Maxmind GeoLite2 Country database.
    - Update geoip6 to the March 3 2015 Maxmind GeoLite2
      Country database.

Changes in version 0.2.5.10 - 2014-10-24
  Tor 0.2.5.10 is the first stable release in the 0.2.5 series.

  It adds several new security features, including improved
  denial-of-service resistance for relays, new compiler hardening
  options, and a system-call sandbox for hardened installations on Linux
  (requires seccomp2). The controller protocol has several new features,
  resolving IPv6 addresses should work better than before, and relays
  should be a little more CPU-efficient. We've added support for more
  OpenBSD and FreeBSD transparent proxy types. We've improved the build
  system and testing infrastructure to allow unit testing of more parts
  of the Tor codebase. Finally, we've addressed several nagging pluggable
  transport usability issues, and included numerous other small bugfixes
  and features mentioned below.

  This release marks end-of-life for Tor 0.2.3.x; those Tor versions
  have accumulated many known flaws; everyone should upgrade.

  o Major features (security):
    - The ntor handshake is now on-by-default, no matter what the
      directory authorities recommend. Implements ticket 8561.
    - Make the "tor-gencert" tool used by directory authority operators
      create 2048-bit signing keys by default (rather than 1024-bit, since
      1024-bit is uncomfortably small these days). Addresses ticket 10324.
    - Warn about attempts to run hidden services and relays in the same
      process: that's probably not a good idea. Closes ticket 12908.
    - Disable support for SSLv3. All versions of OpenSSL in use with Tor
      today support TLS 1.0 or later, so we can safely turn off support
      for this old (and insecure) protocol. Fixes bug 13426.

  o Major features (relay security, DoS-resistance):
    - When deciding whether we have run out of memory and we need to
      close circuits, also consider memory allocated in buffers for
      streams attached to each circuit.

      This change, which extends an anti-DoS feature introduced in
      0.2.4.13-alpha and improved in 0.2.4.14-alpha, lets Tor exit relays
      better resist more memory-based DoS attacks than before. Since the
      MaxMemInCellQueues option now applies to all queues, it is renamed
      to MaxMemInQueues. This feature fixes bug 10169.
    - Avoid hash-flooding denial-of-service attacks by using the secure
      SipHash-2-4 hash function for our hashtables. Without this
      feature, an attacker could degrade performance of a targeted
      client or server by flooding their data structures with a large
      number of entries to be stored at the same hash table position,
      thereby slowing down the Tor instance. With this feature, hash
      table positions are derived from a randomized cryptographic key,
      and an attacker cannot predict which entries will collide. Closes
      ticket 4900.
    - If you don't specify MaxMemInQueues yourself, Tor now tries to
      pick a good value based on your total system memory. Previously,
      the default was always 8 GB. You can still override the default by
      setting MaxMemInQueues yourself. Resolves ticket 11396.

  o Major features (bridges and pluggable transports):
    - Add support for passing arguments to managed pluggable transport
      proxies. Implements ticket 3594.
    - Bridges now track GeoIP information and the number of their users
      even when pluggable transports are in use, and report usage
      statistics in their extra-info descriptors. Resolves tickets 4773
      and 5040.
    - Don't launch pluggable transport proxies if we don't have any
      bridges configured that would use them. Now we can list many
      pluggable transports, and Tor will dynamically start one when it
      hears a bridge address that needs it. Resolves ticket 5018.
    - The bridge directory authority now assigns status flags (Stable,
      Guard, etc) to bridges based on thresholds calculated over all
      Running bridges. Now bridgedb can finally make use of its features
      to e.g. include at least one Stable bridge in its answers. Fixes
      bug 9859.

  o Major features (controller):
    - Extend ORCONN controller event to include an "ID" parameter,
      and add four new controller event types CONN_BW, CIRC_BW,
      CELL_STATS, and TB_EMPTY that show connection and circuit usage.
      The new events are emitted in private Tor networks only, with the
      goal of being able to better track performance and load during
      full-network simulations. Implements proposal 218 and ticket 7359.

  o Major features (relay performance):
    - Speed up server-side lookups of rendezvous and introduction point
      circuits by using hashtables instead of linear searches. These
      functions previously accounted between 3 and 7% of CPU usage on
      some busy relays. Resolves ticket 9841.
    - Avoid wasting CPU when extending a circuit over a channel that is
      nearly out of circuit IDs. Previously, we would do a linear scan
      over possible circuit IDs before finding one or deciding that we
      had exhausted our possibilities. Now, we try at most 64 random
      circuit IDs before deciding that we probably won't succeed. Fixes
      a possible root cause of ticket 11553.

  o Major features (seccomp2 sandbox, Linux only):
    - Use the seccomp2 syscall filtering facility on Linux to limit
      which system calls Tor can invoke. This is an experimental,
      Linux-only feature to provide defense-in-depth against unknown
      attacks. To try turning it on, set "Sandbox 1" in your torrc
      file. Please be ready to report bugs. We hope to add support
      for better sandboxing in the future, including more fine-grained
      filters, better division of responsibility, and support for more
      platforms. This work has been done by Cristian-Matei Toader for
      Google Summer of Code. Resolves tickets 11351 and 11465.

  o Major features (testing networks):
    - Make testing Tor networks bootstrap better: lower directory fetch
      retry schedules and maximum interval without directory requests,
      and raise maximum download tries. Implements ticket 6752.
    - Add make target 'test-network' to run tests on a Chutney network.
      Implements ticket 8530.

  o Major features (other):
    - On some platforms (currently: recent OSX versions, glibc-based
      platforms that support the ELF format, and a few other
      Unix-like operating systems), Tor can now dump stack traces
      when a crash occurs or an assertion fails. By default, traces
      are dumped to stderr (if possible) and to any logs that are
      reporting errors. Implements ticket 9299.

  o Deprecated versions:
    - Tor 0.2.3.x has reached end-of-life; it has received no patches or
      attention for some while.

  o Major bugfixes (security, directory authorities):
    - Directory authorities now include a digest of each relay's
      identity key as a part of its microdescriptor.

      This is a workaround for bug 11743 (reported by "cypherpunks"),
      where Tor clients do not support receiving multiple
      microdescriptors with the same SHA256 digest in the same
      consensus. When clients receive a consensus like this, they only
      use one of the relays. Without this fix, a hostile relay could
      selectively disable some client use of target relays by
      constructing a router descriptor with a different identity and the
      same microdescriptor parameters and getting the authorities to
      list it in a microdescriptor consensus. This fix prevents an
      attacker from causing a microdescriptor collision, because the
      router's identity is not forgeable.

  o Major bugfixes (openssl bug workaround):
    - Avoid crashing when using OpenSSL version 0.9.8zc, 1.0.0o, or
      1.0.1j, built with the 'no-ssl3' configuration option. Fixes
      bug 13471. This is a workaround for an OpenSSL bug.

  o Major bugfixes (client):
    - Perform circuit cleanup operations even when circuit
      construction operations are disabled (because the network is
      disabled, or because there isn't enough directory information).
      Previously, when we were not building predictive circuits, we
      were not closing expired circuits either. Fixes bug 8387; bugfix on
      0.1.1.11-alpha. This bug became visible in 0.2.4.10-alpha when we
      became more strict about when we have "enough directory information
      to build circuits".

  o Major bugfixes (client, pluggable transports):
    - When managing pluggable transports, use OS notification facilities
      to learn if they have crashed, and don't attempt to kill any
      process that has already exited. Fixes bug 8746; bugfix
      on 0.2.3.6-alpha.

  o Major bugfixes (relay denial of service):
    - Instead of writing destroy cells directly to outgoing connection
      buffers, queue them and intersperse them with other outgoing cells.
      This can prevent a set of resource starvation conditions where too
      many pending destroy cells prevent data cells from actually getting
      delivered. Reported by "oftc_must_be_destroyed". Fixes bug 7912;
      bugfix on 0.2.0.1-alpha.

  o Major bugfixes (relay):
    - Avoid queuing or sending destroy cells for circuit ID zero when we
      fail to send a CREATE cell. Fixes bug 12848; bugfix on 0.0.8pre1.
      Found and fixed by "cypherpunks".
    - Fix ORPort reachability detection on relays running behind a
      proxy, by correctly updating the "local" mark on the controlling
      channel when changing the address of an or_connection_t after the
      handshake. Fixes bug 12160; bugfix on 0.2.4.4-alpha.
    - Use a direct dirport connection when uploading non-anonymous
      descriptors to the directory authorities. Previously, relays would
      incorrectly use tunnel connections under a fairly wide variety of
      circumstances. Fixes bug 11469; bugfix on 0.2.4.3-alpha.
    - When a circuit accidentally has the same circuit ID for its
      forward and reverse direction, correctly detect the direction of
      cells using that circuit. Previously, this bug made roughly one
      circuit in a million non-functional. Fixes bug 12195; this is a
      bugfix on every version of Tor.

  o Minor features (security):
    - New --enable-expensive-hardening option to enable security
      hardening options that consume nontrivial amounts of CPU and
      memory. Right now, this includes AddressSanitizer and UbSan, which
      are supported in newer versions of GCC and Clang. Closes ticket
      11477.
    - Authorities now assign the Guard flag to the fastest 25% of the
      network (it used to be the fastest 50%). Also raise the consensus
      weight that guarantees the Guard flag from 250 to 2000. For the
      current network, this results in about 1100 guards, down from 2500.
      This step paves the way for moving the number of entry guards
      down to 1 (proposal 236) while still providing reasonable expected
      performance for most users. Implements ticket 12690.

  o Minor features (security, memory management):
    - Memory allocation tricks (mempools and buffer freelists) are now
      disabled by default. You can turn them back on with
      --enable-mempools and --enable-buf-freelists respectively. We're
      disabling these features because malloc performance is good enough
      on most platforms, and a similar feature in OpenSSL exacerbated
      exploitation of the Heartbleed attack. Resolves ticket 11476.

  o Minor features (bridge client):
    - Report a more useful failure message when we can't connect to a
      bridge because we don't have the right pluggable transport
      configured. Resolves ticket 9665. Patch from Fábio J. Bertinatto.

  o Minor features (bridge):
    - Add an ExtORPortCookieAuthFileGroupReadable option to make the
      cookie file for the ExtORPort g+r by default.

  o Minor features (bridges, pluggable transports):
    - Bridges now write the SHA1 digest of their identity key
      fingerprint (that is, a hash of a hash of their public key) to
      notice-level logs, and to a new hashed-fingerprint file. This
      information will help bridge operators look up their bridge in
      Globe and similar tools. Resolves ticket 10884.
    - Improve the message that Tor displays when running as a bridge
      using pluggable transports without an Extended ORPort listener.
      Also, log the message in the log file too. Resolves ticket 11043.
    - Add threshold cutoffs to the networkstatus document created by
      the Bridge Authority. Fixes bug 1117.
    - On Windows, spawn background processes using the CREATE_NO_WINDOW
      flag. Now Tor Browser Bundle 3.5 with pluggable transports enabled
      doesn't pop up a blank console window. (In Tor Browser Bundle 2.x,
      Vidalia set this option for us.) Implements ticket 10297.

  o Minor features (build):
    - The configure script has a --disable-seccomp option to turn off
      support for libseccomp on systems that have it, in case it (or
      Tor's use of it) is broken. Resolves ticket 11628.
    - Assume that a user using ./configure --host wants to cross-compile,
      and give an error if we cannot find a properly named
      tool-chain. Add a --disable-tool-name-check option to proceed
      nevertheless. Addresses ticket 9869. Patch by Benedikt Gollatz.
    - If we run ./configure and the compiler recognizes -fstack-protector
      but the linker rejects it, warn the user about a potentially missing
      libssp package. Addresses ticket 9948. Patch from Benedikt Gollatz.
    - Add support for `--library-versions` flag. Implements ticket 6384.
    - Return the "unexpected sendme" warnings to a warn severity, but make
      them rate limited, to help diagnose ticket 8093.
    - Detect a missing asciidoc, and warn the user about it, during
      configure rather than at build time. Fixes issue 6506. Patch from
      Arlo Breault.

  o Minor features (client):
    - Add a new option, PredictedPortsRelevanceTime, to control how long
      after having received a request to connect to a given port Tor
      will try to keep circuits ready in anticipation of future requests
      for that port. Patch from "unixninja92"; implements ticket 9176.

  o Minor features (config options and command line):
    - Add an --allow-missing-torrc commandline option that tells Tor to
      run even if the configuration file specified by -f is not available.
      Implements ticket 10060.
    - Add support for the TPROXY transparent proxying facility on Linux.
      See documentation for the new TransProxyType option for more
      details. Implementation by "thomo". Closes ticket 10582.

  o Minor features (config options):
    - Config (torrc) lines now handle fingerprints which are missing
      their initial '$'. Resolves ticket 4341; improvement over 0.0.9pre5.
    - Support a --dump-config option to print some or all of the
      configured options. Mainly useful for debugging the command-line
      option parsing code. Helps resolve ticket 4647.
    - Raise awareness of safer logging: notify user of potentially
      unsafe config options, like logging more verbosely than severity
      "notice" or setting SafeLogging to 0. Resolves ticket 5584.
    - Add a new configuration option TestingV3AuthVotingStartOffset
      that bootstraps a network faster by changing the timing for
      consensus votes. Addresses ticket 8532.
    - Add a new torrc option "ServerTransportOptions" that allows
      bridge operators to pass configuration parameters to their
      pluggable transports. Resolves ticket 8929.
    - The config (torrc) file now accepts bandwidth and space limits in
      bits as well as bytes. (Anywhere that you can say "2 Kilobytes",
      you can now say "16 kilobits", and so on.) Resolves ticket 9214.
      Patch by CharlieB.

  o Minor features (controller):
    - Make the entire exit policy available from the control port via
      GETINFO exit-policy/*. Implements enhancement 7952. Patch from
      "rl1987".
    - Because of the fix for ticket 11396, the real limit for memory
      usage may no longer match the configured MaxMemInQueues value. The
      real limit is now exposed via GETINFO limits/max-mem-in-queues.
    - Add a new "HS_DESC" controller event that reports activities
      related to hidden service descriptors. Resolves ticket 8510.
    - New "DROPGUARDS" controller command to forget all current entry
      guards. Not recommended for ordinary use, since replacing guards
      too frequently makes several attacks easier. Resolves ticket 9934;
      patch from "ra".
    - Implement the TRANSPORT_LAUNCHED control port event that
      notifies controllers about new launched pluggable
      transports. Resolves ticket 5609.

  o Minor features (diagnostic):
    - When logging a warning because of bug 7164, additionally check the
      hash table for consistency (as proposed on ticket 11737). This may
      help diagnose bug 7164.
    - When we log a heartbeat, log how many one-hop circuits we have
      that are at least 30 minutes old, and log status information about
      a few of them. This is an attempt to track down bug 8387.
    - When encountering an unexpected CR while writing text to a file on
      Windows, log the name of the file. Should help diagnosing
      bug 11233.
    - Give more specific warnings when a client notices that an onion
      handshake has failed. Fixes ticket 9635.
    - Add significant new logging code to attempt to diagnose bug 12184,
      where relays seem to run out of available circuit IDs.
    - Improve the diagnostic log message for bug 8387 even further to
      try to improve our odds of figuring out why one-hop directory
      circuits sometimes do not get closed.
    - Add more log messages to diagnose bug 7164, which causes
      intermittent "microdesc_free() called but md was still referenced"
      warnings. We now include more information, to figure out why we
      might be cleaning a microdescriptor for being too old if it's
      still referenced by a live node_t object.
    - Log current accounting state (bytes sent and received + remaining
      time for the current accounting period) in the relay's heartbeat
      message. Implements ticket 5526; patch from Peter Retzlaff.

  o Minor features (geoip):
    - Update geoip and geoip6 to the August 7 2014 Maxmind GeoLite2
      Country database.

  o Minor features (interface):
    - Generate a warning if any ports are listed in the SocksPolicy,
      DirPolicy, AuthDirReject, AuthDirInvalid, AuthDirBadDir, or
      AuthDirBadExit options. (These options only support address
      ranges.) Fixes part of ticket 11108.

  o Minor features (kernel API usage):
    - Use the SOCK_NONBLOCK socket type, if supported, to open nonblocking
      sockets in a single system call. Implements ticket 5129.

  o Minor features (log messages):
    - When ServerTransportPlugin is set on a bridge, Tor can write more
      useful statistics about bridge use in its extrainfo descriptors,
      but only if the Extended ORPort ("ExtORPort") is set too. Add a
      log message to inform the user in this case. Resolves ticket 9651.
    - When receiving a new controller connection, log the origin address.
      Resolves ticket 9698; patch from "sigpipe".
    - When logging OpenSSL engine status at startup, log the status of
      more engines. Fixes ticket 10043; patch from Joshua Datko.

  o Minor features (log verbosity):
    - Demote the message that we give when a flushing connection times
      out for too long from NOTICE to INFO. It was usually meaningless.
      Resolves ticket 5286.
    - Don't log so many notice-level bootstrapping messages at startup
      about downloading descriptors. Previously, we'd log a notice
      whenever we learned about more routers. Now, we only log a notice
      at every 5% of progress. Fixes bug 9963.
    - Warn less verbosely when receiving a malformed
      ESTABLISH_RENDEZVOUS cell. Fixes ticket 11279.

  o Minor features (performance):
    - If we're using the pure-C 32-bit curve25519_donna implementation
      of curve25519, build it with the -fomit-frame-pointer option to
      make it go faster on register-starved hosts. This improves our
      handshake performance by about 6% on i386 hosts without nacl.
      Closes ticket 8109.

  o Minor features (relay):
    - If a circuit timed out for at least 3 minutes, check if we have a
      new external IP address, and publish a new descriptor with the new
      IP address if it changed. Resolves ticket 2454.

  o Minor features (testing):
    - If Python is installed, "make check" now runs extra tests beyond
      the unit test scripts.
    - When bootstrapping a test network, sometimes very few relays get
      the Guard flag. Now a new option "TestingDirAuthVoteGuard" can
      specify a set of relays which should be voted Guard regardless of
      their uptime or bandwidth. Addresses ticket 9206.

  o Minor features (transparent proxy, *BSD):
    - Support FreeBSD's ipfw firewall interface for TransPort ports on
      FreeBSD. To enable it, set "TransProxyType ipfw". Resolves ticket
      10267; patch from "yurivict".
    - Support OpenBSD's divert-to rules with the pf firewall for
      transparent proxy ports. To enable it, set "TransProxyType
      pf-divert". This allows Tor to run a TransPort transparent proxy
      port on OpenBSD 4.4 or later without root privileges. See the
      pf.conf(5) manual page for information on configuring pf to use
      divert-to rules. Closes ticket 10896; patch from Dana Koch.

  o Minor bugfixes (bridge client):
    - Stop accepting bridge lines containing hostnames. Doing so would
      cause clients to perform DNS requests on the hostnames, which was
      not sensible behavior. Fixes bug 10801; bugfix on 0.2.0.1-alpha.

  o Minor bugfixes (bridges):
    - Avoid potential crashes or bad behavior when launching a
      server-side managed proxy with ORPort or ExtORPort temporarily
      disabled. Fixes bug 9650; bugfix on 0.2.3.16-alpha.
    - Fix a bug where the first connection works to a bridge that uses a
      pluggable transport with client-side parameters, but we don't send
      the client-side parameters on subsequent connections. (We don't
      use any pluggable transports with client-side parameters yet,
      but ScrambleSuit will soon become the first one.) Fixes bug 9162;
      bugfix on 0.2.0.3-alpha. Based on a patch from "rl1987".

  o Minor bugfixes (build, auxiliary programs):
    - Stop preprocessing the "torify" script with autoconf, since
      it no longer refers to LOCALSTATEDIR. Fixes bug 5505; patch
      from Guilhem.
    - The tor-fw-helper program now follows the standard convention and
      exits with status code "0" on success. Fixes bug 9030; bugfix on
      0.2.3.1-alpha. Patch by Arlo Breault.
    - Corrected ./configure advice for what openssl dev package you should
      install on Debian. Fixes bug 9207; bugfix on 0.2.0.1-alpha.

  o Minor bugfixes (client):
    - Avoid "Tried to open a socket with DisableNetwork set" warnings
      when starting a client with bridges configured and DisableNetwork
      set. (Tor launcher starts Tor with DisableNetwork set the first
      time it runs.) Fixes bug 10405; bugfix on 0.2.3.9-alpha.
    - Improve the log message when we can't connect to a hidden service
      because all of the hidden service directory nodes hosting its
      descriptor are excluded. Improves on our fix for bug 10722, which
      was a bugfix on 0.2.0.10-alpha.
    - Raise a control port warning when we fail to connect to all of
      our bridges. Previously, we didn't inform the controller, and
      the bootstrap process would stall. Fixes bug 11069; bugfix on
      0.2.1.2-alpha.
    - Exit immediately when a process-owning controller exits.
      Previously, tor relays would wait for a little while after their
      controller exited, as if they had gotten an INT signal -- but this
      was problematic, since there was no feedback for the user. To do a
      clean shutdown, controllers should send an INT signal and give Tor
      a chance to clean up. Fixes bug 10449; bugfix on 0.2.2.28-beta.
    - Stop attempting to connect to bridges before our pluggable
      transports are configured (harmless but resulted in some erroneous
      log messages). Fixes bug 11156; bugfix on 0.2.3.2-alpha.
    - Fix connections to IPv6 addresses over SOCKS5. Previously, we were
      generating incorrect SOCKS5 responses, and confusing client
      applications. Fixes bug 10987; bugfix on 0.2.4.7-alpha.

  o Minor bugfixes (client, DNSPort):
    - When using DNSPort, try to respond to AAAA requests with AAAA
      answers. Previously, we hadn't looked at the request type when
      deciding which answer type to prefer. Fixes bug 10468; bugfix on
      0.2.4.7-alpha.
    - When receiving a DNS query for an unsupported record type, reply
      with no answer rather than with a NOTIMPL error. This behavior
      isn't correct either, but it will break fewer client programs, we
      hope. Fixes bug 10268; bugfix on 0.2.0.1-alpha. Original patch
      from "epoch".

  o Minor bugfixes (client, logging during bootstrap):
    - Only report the first fatal bootstrap error on a given OR
      connection. This stops us from telling the controller bogus error
      messages like "DONE". Fixes bug 10431; bugfix on 0.2.1.1-alpha.
    - Avoid generating spurious warnings when starting with
      DisableNetwork enabled. Fixes bug 11200 and bug 10405; bugfix on
      0.2.3.9-alpha.

  o Minor bugfixes (closing OR connections):
    - If write_to_buf() in connection_write_to_buf_impl_() ever fails,
      check if it's an or_connection_t and correctly call
      connection_or_close_for_error() rather than
      connection_mark_for_close() directly. Fixes bug 11304; bugfix on
      0.2.4.4-alpha.
    - When closing all connections on setting DisableNetwork to 1, use
      connection_or_close_normally() rather than closing OR connections
      out from under the channel layer. Fixes bug 11306; bugfix on
      0.2.4.4-alpha.

  o Minor bugfixes (code correctness):
    - Previously we used two temporary files when writing descriptors to
      disk; now we only use one. Fixes bug 1376.
    - Remove an erroneous (but impossible and thus harmless) pointer
      comparison that would have allowed compilers to skip a bounds
      check in channeltls.c. Fixes bugs 10313 and 9980; bugfix on
      0.2.0.10-alpha. Noticed by Jared L Wong and David Fifield.
    - Fix an always-true assertion in pluggable transports code so it
      actually checks what it was trying to check. Fixes bug 10046;
      bugfix on 0.2.3.9-alpha. Found by "dcb".

  o Minor bugfixes (command line):
    - Use a single command-line parser for parsing torrc options on the
      command line and for finding special command-line options to avoid
      inconsistent behavior for torrc option arguments that have the same
      names as command-line options. Fixes bugs 4647 and 9578; bugfix on
      0.0.9pre5.
    - No longer allow 'tor --hash-password' with no arguments. Fixes bug
      9573; bugfix on 0.0.9pre5.

  o Minor bugfixes (compilation):
    - Compile correctly with builds and forks of OpenSSL (such as
      LibreSSL) that disable compression. Fixes bug 12602; bugfix on
      0.2.1.1-alpha. Patch from "dhill".
    - Restore the ability to compile Tor with V2_HANDSHAKE_SERVER
      turned off (that is, without support for v2 link handshakes). Fixes
      bug 4677; bugfix on 0.2.3.2-alpha. Patch from "piet".
    - In routerlist_assert_ok(), don't take the address of a
      routerinfo's cache_info member unless that routerinfo is non-NULL.
      Fixes bug 13096; bugfix on 0.1.1.9-alpha. Patch by "teor".
    - Fix a large number of false positive warnings from the clang
      analyzer static analysis tool. This should make real warnings
      easier for clang analyzer to find. Patch from "teor". Closes
      ticket 13036.
    - Resolve GCC complaints on OpenBSD about discarding constness in
      TO_{ORIGIN,OR}_CIRCUIT functions. Fixes part of bug 11633; bugfix
      on 0.1.1.23. Patch from Dana Koch.
    - Resolve clang complaints on OpenBSD with -Wshorten-64-to-32 due to
      treatment of long and time_t as comparable types. Fixes part of
      bug 11633. Patch from Dana Koch.
    - When deciding whether to build the 64-bit curve25519
      implementation, detect platforms where we can compile 128-bit
      arithmetic but cannot link it. Fixes bug 11729; bugfix on
      0.2.4.8-alpha. Patch from "conradev".
    - Fix compilation when DNS_CACHE_DEBUG is enabled. Fixes bug 11761;
      bugfix on 0.2.3.13-alpha. Found by "cypherpunks".
    - Fix compilation with dmalloc. Fixes bug 11605; bugfix
      on 0.2.4.10-alpha.
    - Build and run correctly on systems like OpenBSD-current that have
      patched OpenSSL to remove get_cipher_by_char and/or its
      implementations. Fixes issue 13325.

  o Minor bugfixes (controller and command-line):
    - If changing a config option via "setconf" fails in a recoverable
      way, we used to nonetheless write our new control ports to the
      file described by the "ControlPortWriteToFile" option. Now we only
      write out that file if we successfully switch to the new config
      option. Fixes bug 5605; bugfix on 0.2.2.26-beta. Patch from "Ryman".

  o Minor bugfixes (directory server):
    - No longer accept malformed http headers when parsing urls from
      headers. Now we reply with Bad Request ("400"). Fixes bug 2767;
      bugfix on 0.0.6pre1.
    - When sending a compressed set of descriptors or microdescriptors,
      make sure to finalize the zlib stream. Previously, we would write
      all the compressed data, but if the last descriptor we wanted to
      send was missing or too old, we would not mark the stream as
      finished. This caused problems for decompression tools. Fixes bug
      11648; bugfix on 0.1.1.23.

  o Minor bugfixes (hidden service):
    - Only retry attempts to connect to a chosen rendezvous point 8
      times, not 30. Fixes bug 4241; bugfix on 0.1.0.1-rc.

  o Minor bugfixes (interface):
    - Reject relative control socket paths and emit a warning. Previously,
      single-component control socket paths would be rejected, but Tor
      would not log why it could not validate the config. Fixes bug 9258;
      bugfix on 0.2.3.16-alpha.

  o Minor bugfixes (log messages):
    - Fix a bug where clients using bridges would report themselves
      as 50% bootstrapped even without a live consensus document.
      Fixes bug 9922; bugfix on 0.2.1.1-alpha.
    - Suppress a warning where, if there's only one directory authority
      in the network, we would complain that votes and signatures cannot
      be uploaded to other directory authorities. Fixes bug 10842;
      bugfix on 0.2.2.26-beta.
    - Report bootstrapping progress correctly when we're downloading
      microdescriptors. We had updated our "do we have enough microdescs
      to begin building circuits?" logic most recently in 0.2.4.10-alpha
      (see bug 5956), but we left the bootstrap status event logic at
      "how far through getting 1/4 of them are we?" Fixes bug 9958;
      bugfix on 0.2.2.36, which is where they diverged (see bug 5343).

  o Minor bugfixes (logging):
    - Downgrade "Unexpected onionskin length after decryption" warning
      to a protocol-warn, since there's nothing relay operators can do
      about a client that sends them a malformed create cell. Resolves
      bug 12996; bugfix on 0.0.6rc1.
    - Log more specific warnings when we get an ESTABLISH_RENDEZVOUS
      cell on a cannibalized or non-OR circuit. Resolves ticket 12997.
    - When logging information about an EXTEND2 or EXTENDED2 cell, log
      their names correctly. Fixes part of bug 12700; bugfix
      on 0.2.4.8-alpha.
    - When logging information about a relay cell whose command we don't
      recognize, log its command as an integer. Fixes part of bug 12700;
      bugfix on 0.2.1.10-alpha.
    - Escape all strings from the directory connection before logging
      them. Fixes bug 13071; bugfix on 0.1.1.15. Patch from "teor".
    - Squelch a spurious LD_BUG message "No origin circuit for
      successful SOCKS stream" in certain hidden service failure cases;
      fixes bug 10616.
    - Downgrade the severity of the 'unexpected sendme cell from client'
      from 'warn' to 'protocol warning'. Closes ticket 8093.

  o Minor bugfixes (misc code correctness):
    - In munge_extrainfo_into_routerinfo(), check the return value of
      memchr(). This would have been a serious issue if we ever passed
      it a non-extrainfo. Fixes bug 8791; bugfix on 0.2.0.6-alpha. Patch
      from Arlo Breault.
    - On the chance that somebody manages to build Tor on a
      platform where time_t is unsigned, correct the way that
      microdesc_add_to_cache() handles negative time arguments.
      Fixes bug 8042; bugfix on 0.2.3.1-alpha.
    - Fix various instances of undefined behavior in channeltls.c,
      tor_memmem(), and eventdns.c that would cause us to construct
      pointers to memory outside an allocated object. (These invalid
      pointers were not accessed, but C does not even allow them to
      exist.) Fixes bug 10363; bugfixes on 0.1.1.1-alpha, 0.1.2.1-alpha,
      0.2.0.10-alpha, and 0.2.3.6-alpha. Reported by "bobnomnom".
    - Use the AddressSanitizer and Ubsan sanitizers (in clang-3.4) to
      fix some miscellaneous errors in our tests and codebase. Fixes bug
      11232. Bugfixes on versions back as far as 0.2.1.11-alpha.
    - Always check return values for unlink, munmap, UnmapViewOfFile;
      check strftime return values more often. In some cases all we can
      do is report a warning, but this may help prevent deeper bugs from
      going unnoticed. Closes ticket 8787; bugfixes on many, many tor
      versions.
    - Fix numerous warnings from the clang "scan-build" static analyzer.
      Some of these are programming style issues; some of them are false
      positives that indicated awkward code; some are undefined behavior
      cases related to constructing (but not using) invalid pointers;
      some are assumptions about API behavior; some are (harmlessly)
      logging sizeof(ptr) bytes from a token when sizeof(*ptr) would be
      correct; and one or two are genuine bugs that weren't reachable
      from the rest of the program. Fixes bug 8793; bugfixes on many,
      many tor versions.

  o Minor bugfixes (node selection):
    - If ExcludeNodes is set, consider non-excluded hidden service
      directory servers before excluded ones. Do not consider excluded
      hidden service directory servers at all if StrictNodes is
      set. (Previously, we would sometimes decide to connect to those
      servers, and then realize before we initiated a connection that
      we had excluded them.) Fixes bug 10722; bugfix on 0.2.0.10-alpha.
      Reported by "mr-4".
    - If we set the ExitNodes option but it doesn't include any nodes
      that have the Exit flag, we would choose not to bootstrap. Now we
      bootstrap so long as ExitNodes includes nodes which can exit to
      some port. Fixes bug 10543; bugfix on 0.2.4.10-alpha.

  o Minor bugfixes (performance):
    - Avoid a bug where every successful connection made us recompute
      the flag telling us whether we have sufficient information to
      build circuits. Previously, we would forget our cached value
      whenever we successfully opened a channel (or marked a router as
      running or not running for any other reason), regardless of
      whether we had previously believed the router to be running. This
      forced us to run an expensive update operation far too often.
      Fixes bug 12170; bugfix on 0.1.2.1-alpha.
    - Avoid using tor_memeq() for checking relay cell integrity. This
      removes a possible performance bottleneck. Fixes part of bug
      12169; bugfix on 0.2.1.31.

  o Minor bugfixes (platform-specific):
    - When dumping a malformed directory object to disk, save it in
      binary mode on Windows, not text mode. Fixes bug 11342; bugfix on
      0.2.2.1-alpha.
    - Don't report failures from make_socket_reuseable() on incoming
      sockets on OSX: this can happen when incoming connections close
      early. Fixes bug 10081.

  o Minor bugfixes (pluggable transports):
    - Avoid another 60-second delay when starting Tor in a pluggable-
      transport-using configuration when we already have cached
      descriptors for our bridges. Fixes bug 11965; bugfix
      on 0.2.3.6-alpha.

  o Minor bugfixes (protocol correctness):
    - When receiving a VERSIONS cell with an odd number of bytes, close
      the connection immediately since the cell is malformed. Fixes bug
      10365; bugfix on 0.2.0.10-alpha. Spotted by "bobnomnom"; fix by
      "rl1987".

  o Minor bugfixes (relay, other):
    - We now drop CREATE cells for already-existent circuit IDs and for
      zero-valued circuit IDs, regardless of other factors that might
      otherwise have called for DESTROY cells. Fixes bug 12191; bugfix
      on 0.0.8pre1.
    - When rejecting DATA cells for stream_id zero, still count them
      against the circuit's deliver window so that we don't fail to send
      a SENDME. Fixes bug 11246; bugfix on 0.2.4.10-alpha.

  o Minor bugfixes (relay, threading):
    - Check return code on spawn_func() in cpuworker code, so that we
      don't think we've spawned a nonworking cpuworker and write junk to
      it forever. Fix related to bug 4345; bugfix on all released Tor
      versions. Found by "skruffy".
    - Use a pthread_attr to make sure that spawn_func() cannot return an
      error while at the same time launching a thread. Fix related to
      bug 4345; bugfix on all released Tor versions. Reported
      by "cypherpunks".

  o Minor bugfixes (relays and bridges):
    - Avoid crashing on a malformed resolv.conf file when running a
      relay using Libevent 1. Fixes bug 8788; bugfix on 0.1.1.23.
    - Non-exit relays no longer launch mock DNS requests to check for
      DNS hijacking. This has been unnecessary since 0.2.1.7-alpha, when
      non-exit relays stopped servicing DNS requests. Fixes bug 965;
      bugfix on 0.2.1.7-alpha. Patch from Matt Pagan.
    - Bridges now report complete directory request statistics. Related
      to bug 5824; bugfix on 0.2.2.1-alpha.
    - Bridges now never collect statistics that were designed for
      relays. Fixes bug 5824; bugfix on 0.2.3.8-alpha.

  o Minor bugfixes (testing):
    - Fix all valgrind warnings produced by the unit tests. There were
      over a thousand memory leak warnings previously, mostly produced
      by forgetting to free things in the unit test code. Fixes bug
      11618, bugfixes on many versions of Tor.

  o Minor bugfixes (tor-fw-helper):
    - Give a correct log message when tor-fw-helper fails to launch.
      (Previously, we would say something like "tor-fw-helper sent us a
      string we could not parse".) Fixes bug 9781; bugfix
      on 0.2.4.2-alpha.

  o Minor bugfixes (trivial memory leaks):
    - Fix a small memory leak when signing a directory object. Fixes bug
      11275; bugfix on 0.2.4.13-alpha.
    - Resolve some memory leaks found by coverity in the unit tests, on
      exit in tor-gencert, and on a failure to compute digests for our
      own keys when generating a v3 networkstatus vote. These leaks
      should never have affected anyone in practice.

  o Code simplification and refactoring:
    - Remove some old fallback code designed to keep Tor clients working
      in a network with only two working relays. Elsewhere in the code we
      have long since stopped supporting such networks, so there wasn't
      much point in keeping it around. Addresses ticket 9926.
    - Reject 0-length EXTEND2 cells more explicitly. Fixes bug 10536;
      bugfix on 0.2.4.8-alpha. Reported by "cypherpunks".
    - Extract the common duplicated code for creating a subdirectory
      of the data directory and writing to a file in it. Fixes ticket
      4282; patch from Peter Retzlaff.
    - Since OpenSSL 0.9.7, the i2d_*() functions support allocating output
      buffer. Avoid calling twice: i2d_RSAPublicKey(), i2d_DHparams(),
      i2d_X509(), and i2d_PublicKey(). Resolves ticket 5170.
    - Add a set of accessor functions for the circuit timeout data
      structure. Fixes ticket 6153; patch from "piet".
    - Clean up exit paths from connection_listener_new(). Closes ticket
      8789. Patch from Arlo Breault.
    - Since we rely on OpenSSL 0.9.8 now, we can use EVP_PKEY_cmp()
      and drop our own custom pkey_eq() implementation. Fixes bug 9043.
    - Use a doubly-linked list to implement the global circuit list.
      Resolves ticket 9108. Patch from Marek Majkowski.
    - Remove contrib/id_to_fp.c since it wasn't used anywhere.
    - Remove constants and tests for PKCS1 padding; it's insecure and
      shouldn't be used for anything new. Fixes bug 8792; patch
      from Arlo Breault.
    - Remove instances of strcpy() from the unit tests. They weren't
      hurting anything, since they were only in the unit tests, but it's
      embarassing to have strcpy() in the code at all, and some analysis
      tools don't like it. Fixes bug 8790; bugfix on 0.2.3.6-alpha and
      0.2.3.8-alpha. Patch from Arlo Breault.
    - Remove is_internal_IP() function. Resolves ticket 4645.
    - Remove unused function circuit_dump_by_chan from circuitlist.c.
      Closes issue 9107; patch from "marek".
    - Change our use of the ENUM_BF macro to avoid declarations that
      confuse Doxygen.
    - Get rid of router->address, since in all cases it was just the
      string representation of router->addr. Resolves ticket 5528.

  o Documentation:
    - Adjust the URLs in the README to refer to the new locations of
      several documents on the website. Fixes bug 12830. Patch from
      Matt Pagan.
    - Document 'reject6' and 'accept6' ExitPolicy entries. Resolves
      ticket 12878.
    - Update manpage to describe some of the files you can expect to
      find in Tor's DataDirectory. Addresses ticket 9839.
    - Clean up several option names in the manpage to match their real
      names, add the missing documentation for a couple of testing and
      directory authority options, remove the documentation for a
      V2-directory fetching option that no longer exists. Resolves
      ticket 11634.
    - Correct the documenation so that it lists the correct directory
      for the stats files. (They are in a subdirectory called "stats",
      not "status".)
    - In the manpage, move more authority-only options into the
      directory authority section so that operators of regular directory
      caches don't get confused.
    - Fix the layout of the SOCKSPort flags in the manpage. Fixes bug
      11061; bugfix on 0.2.4.7-alpha.
    - Resolve warnings from Doxygen.
    - Document in the manpage that "KBytes" may also be written as
      "kilobytes" or "KB", that "Kbits" may also be written as
      "kilobits", and so forth. Closes ticket 9222.
    - Document that the ClientOnly config option overrides ORPort.
      Our old explanation made ClientOnly sound as though it did
      nothing at all. Resolves bug 9059.
    - Explain that SocksPolicy, DirPolicy, and similar options don't
      take port arguments. Fixes the other part of ticket 11108.
    - Fix a comment about the rend_server_descriptor_t.protocols field
      to more accurately describe its range. Also, make that field
      unsigned, to more accurately reflect its usage. Fixes bug 9099;
      bugfix on 0.2.1.5-alpha.
    - Fix the manpage's description of HiddenServiceAuthorizeClient:
      the maximum client name length is 16, not 19. Fixes bug 11118;
      bugfix on 0.2.1.6-alpha.

  o Package cleanup:
    - The contrib directory has been sorted and tidied. Before, it was
      an unsorted dumping ground for useful and not-so-useful things.
      Now, it is divided based on functionality, and the items which
      seemed to be nonfunctional or useless have been removed. Resolves
      ticket 8966; based on patches from "rl1987".

  o Removed code and features:
    - Clients now reject any directory authority certificates lacking
      a dir-key-crosscert element. These have been included since
      0.2.1.9-alpha, so there's no real reason for them to be optional
      any longer. Completes proposal 157. Resolves ticket 10162.
    - Remove all code that existed to support the v2 directory system,
      since there are no longer any v2 directory authorities. Resolves
      ticket 10758.
    - Remove the HSAuthoritativeDir and AlternateHSAuthority torrc
      options, which were used for designating authorities as "Hidden
      service authorities". There has been no use of hidden service
      authorities since 0.2.2.1-alpha, when we stopped uploading or
      downloading v0 hidden service descriptors. Fixes bug 10881; also
      part of a fix for bug 10841.
    - Remove /tor/dbg-stability.txt URL that was meant to help debug WFU
      and MTBF calculations, but that nobody was using. Fixes bug 11742.
    - The TunnelDirConns and PreferTunnelledDirConns options no longer
      exist; tunneled directory connections have been available since
      0.1.2.5-alpha, and turning them off is not a good idea. This is a
      brute-force fix for 10849, where "TunnelDirConns 0" would break
      hidden services.
    - Remove all code for the long unused v1 directory protocol.
      Resolves ticket 11070.
    - Remove all remaining code related to version-0 hidden service
      descriptors: they have not been in use since 0.2.2.1-alpha. Fixes
      the rest of bug 10841.
    - Remove migration code from when we renamed the "cached-routers"
      file to "cached-descriptors" back in 0.2.0.8-alpha. This
      incidentally resolves ticket 6502 by cleaning up the related code
      a bit. Patch from Akshay Hebbar.

  o Test infrastructure:
    - Tor now builds each source file in two modes: a mode that avoids
      exposing identifiers needlessly, and another mode that exposes
      more identifiers for testing. This lets the compiler do better at
      optimizing the production code, while enabling us to take more
      radical measures to let the unit tests test things.
    - The production builds no longer include functions used only in
      the unit tests; all functions exposed from a module only for
      unit-testing are now static in production builds.
    - Add an --enable-coverage configuration option to make the unit
      tests (and a new src/or/tor-cov target) to build with gcov test
      coverage support.
    - Update to the latest version of tinytest.
    - Improve the tinytest implementation of string operation tests so
      that comparisons with NULL strings no longer crash the tests; they
      now just fail, normally. Fixes bug 9004; bugfix on 0.2.2.4-alpha.
    - New macros in test.h to simplify writing mock-functions for unit
      tests. Part of ticket 11507. Patch from Dana Koch.
    - We now have rudimentary function mocking support that our unit
      tests can use to test functions in isolation. Function mocking
      lets the tests temporarily replace a function's dependencies with
      stub functions, so that the tests can check the function without
      invoking the other functions it calls.

  o Testing:
    - Complete tests for the status.c module. Resolves ticket 11507.
      Patch from Dana Koch.
    - Add more unit tests for the <circid,channel>->circuit map, and
      the destroy-cell-tracking code to fix bug 7912.
    - Unit tests for failing cases of the TAP onion handshake.
    - More unit tests for address-manipulation functions.

  o Distribution (systemd):
    - Include a tor.service file in contrib/dist for use with systemd.
      Some distributions will be able to use this file unmodified;
      others will need to tweak it, or write their own. Patch from Jamie
      Nguyen; resolves ticket 8368.
    - Verify configuration file via ExecStartPre in the systemd unit
      file. Patch from intrigeri; resolves ticket 12730.
    - Explicitly disable RunAsDaemon in the systemd unit file. Our
      current systemd unit uses "Type = simple", so systemd does not
      expect tor to fork. If the user has "RunAsDaemon 1" in their
      torrc, then things won't work as expected. This is e.g. the case
      on Debian (and derivatives), since there we pass "--defaults-torrc
      /usr/share/tor/tor-service-defaults-torrc" (that contains
      "RunAsDaemon 1") by default. Patch by intrigeri; resolves
      ticket 12731.


Changes in version 0.2.4.25 - 2014-10-20
  Tor 0.2.4.25 disables SSL3 in response to the recent "POODLE" attack
  (even though POODLE does not affect Tor). It also works around a crash
  bug caused by some operating systems' response to the "POODLE" attack
  (which does affect Tor).

  o Major security fixes (also in 0.2.5.9-rc):
    - Disable support for SSLv3. All versions of OpenSSL in use with Tor
      today support TLS 1.0 or later, so we can safely turn off support
      for this old (and insecure) protocol. Fixes bug 13426.

  o Major bugfixes (openssl bug workaround, also in 0.2.5.9-rc):
    - Avoid crashing when using OpenSSL version 0.9.8zc, 1.0.0o, or
      1.0.1j, built with the 'no-ssl3' configuration option. Fixes bug
      13471. This is a workaround for an OpenSSL bug.


Changes in version 0.2.4.24 - 2014-09-22
  Tor 0.2.4.24 fixes a bug that affects consistency and speed when
  connecting to hidden services, and it updates the location of one of
  the directory authorities.

  o Major bugfixes:
    - Clients now send the correct address for their chosen rendezvous
      point when trying to access a hidden service. They used to send
      the wrong address, which would still work some of the time because
      they also sent the identity digest of the rendezvous point, and if
      the hidden service happened to try connecting to the rendezvous
      point from a relay that already had a connection open to it,
      the relay would reuse that connection. Now connections to hidden
      services should be more robust and faster. Also, this bug meant
      that clients were leaking to the hidden service whether they were
      on a little-endian (common) or big-endian (rare) system, which for
      some users might have reduced their anonymity. Fixes bug 13151;
      bugfix on 0.2.1.5-alpha.

  o Directory authority changes:
    - Change IP address for gabelmoo (v3 directory authority).

  o Minor features (geoip):
    - Update geoip and geoip6 to the August 7 2014 Maxmind GeoLite2
      Country database.


Changes in version 0.2.4.23 - 2014-07-28
  Tor 0.2.4.23 brings us a big step closer to slowing down the risk from
  guard rotation, and also backports several important fixes from the
  Tor 0.2.5 alpha release series.

  o Major features:
    - Clients now look at the "usecreatefast" consensus parameter to
      decide whether to use CREATE_FAST or CREATE cells for the first hop
      of their circuit. This approach can improve security on connections
      where Tor's circuit handshake is stronger than the available TLS
      connection security levels, but the tradeoff is more computational
      load on guard relays. Implements proposal 221. Resolves ticket 9386.
    - Make the number of entry guards configurable via a new
      NumEntryGuards consensus parameter, and the number of directory
      guards configurable via a new NumDirectoryGuards consensus
      parameter. Implements ticket 12688.

  o Major bugfixes:
    - Fix a bug in the bounds-checking in the 32-bit curve25519-donna
      implementation that caused incorrect results on 32-bit
      implementations when certain malformed inputs were used along with
      a small class of private ntor keys. This bug does not currently
      appear to allow an attacker to learn private keys or impersonate a
      Tor server, but it could provide a means to distinguish 32-bit Tor
      implementations from 64-bit Tor implementations. Fixes bug 12694;
      bugfix on 0.2.4.8-alpha. Bug found by Robert Ransom; fix from
      Adam Langley.

  o Minor bugfixes:
    - Warn and drop the circuit if we receive an inbound 'relay early'
      cell. Those used to be normal to receive on hidden service circuits
      due to bug 1038, but the buggy Tor versions are long gone from
      the network so we can afford to resume watching for them. Resolves
      the rest of bug 1038; bugfix on 0.2.1.19.
    - Correct a confusing error message when trying to extend a circuit
      via the control protocol but we don't know a descriptor or
      microdescriptor for one of the specified relays. Fixes bug 12718;
      bugfix on 0.2.3.1-alpha.
    - Avoid an illegal read from stack when initializing the TLS
      module using a version of OpenSSL without all of the ciphers
      used by the v2 link handshake. Fixes bug 12227; bugfix on
      0.2.4.8-alpha.  Found by "starlight".

  o Minor features:
    - Update geoip and geoip6 to the July 10 2014 Maxmind GeoLite2
      Country database.


Changes in version 0.2.4.22 - 2014-05-16
  Tor 0.2.4.22 backports numerous high-priority fixes from the Tor 0.2.5
  alpha release series. These include blocking all authority signing
  keys that may have been affected by the OpenSSL "heartbleed" bug,
  choosing a far more secure set of TLS ciphersuites by default, closing
  a couple of memory leaks that could be used to run a target relay out
  of RAM, and several others.

  o Major features (security, backport from 0.2.5.4-alpha):
    - Block authority signing keys that were used on authorities
      vulnerable to the "heartbleed" bug in OpenSSL (CVE-2014-0160). (We
      don't have any evidence that these keys _were_ compromised; we're
      doing this to be prudent.) Resolves ticket 11464.

  o Major bugfixes (security, OOM):
    - Fix a memory leak that could occur if a microdescriptor parse
      fails during the tokenizing step. This bug could enable a memory
      exhaustion attack by directory servers. Fixes bug 11649; bugfix
      on 0.2.2.6-alpha.

  o Major bugfixes (TLS cipher selection, backport from 0.2.5.4-alpha):
    - The relay ciphersuite list is now generated automatically based on
      uniform criteria, and includes all OpenSSL ciphersuites with
      acceptable strength and forward secrecy. Previously, we had left
      some perfectly fine ciphersuites unsupported due to omission or
      typo. Resolves bugs 11513, 11492, 11498, 11499. Bugs reported by
      'cypherpunks'. Bugfix on 0.2.4.8-alpha.
    - Relays now trust themselves to have a better view than clients of
      which TLS ciphersuites are better than others. (Thanks to bug
      11513, the relay list is now well-considered, whereas the client
      list has been chosen mainly for anti-fingerprinting purposes.)
      Relays prefer: AES over 3DES; then ECDHE over DHE; then GCM over
      CBC; then SHA384 over SHA256 over SHA1; and last, AES256 over
      AES128. Resolves ticket 11528.
    - Clients now try to advertise the same list of ciphersuites as
      Firefox 28. This change enables selection of (fast) GCM
      ciphersuites, disables some strange old ciphers, and stops
      advertising the ECDH (not to be confused with ECDHE) ciphersuites.
      Resolves ticket 11438.

  o Minor bugfixes (configuration, security):
    - When running a hidden service, do not allow TunneledDirConns 0:
      trying to set that option together with a hidden service would
      otherwise prevent the hidden service from running, and also make
      it publish its descriptors directly over HTTP. Fixes bug 10849;
      bugfix on 0.2.1.1-alpha.

  o Minor bugfixes (controller, backport from 0.2.5.4-alpha):
    - Avoid sending a garbage value to the controller when a circuit is
      cannibalized. Fixes bug 11519; bugfix on 0.2.3.11-alpha.

  o Minor bugfixes (exit relay, backport from 0.2.5.4-alpha):
    - Stop leaking memory when we successfully resolve a PTR record.
      Fixes bug 11437; bugfix on 0.2.4.7-alpha.

  o Minor bugfixes (bridge client, backport from 0.2.5.4-alpha):
    - Avoid 60-second delays in the bootstrapping process when Tor is
      launching for a second time while using bridges. Fixes bug 9229;
      bugfix on 0.2.0.3-alpha.

  o Minor bugfixes (relays and bridges, backport from 0.2.5.4-alpha):
    - Give the correct URL in the warning message when trying to run a
      relay on an ancient version of Windows. Fixes bug 9393.

  o Minor bugfixes (compilation):
    - Fix a compilation error when compiling with --disable-curve25519.
      Fixes bug 9700; bugfix on 0.2.4.17-rc.

  o Minor bugfixes:
    - Downgrade the warning severity for the the "md was still
      referenced 1 node(s)" warning. Tor 0.2.5.4-alpha has better code
      for trying to diagnose this bug, and the current warning in
      earlier versions of tor achieves nothing useful. Addresses warning
      from bug 7164.

  o Minor features (log verbosity, backport from 0.2.5.4-alpha):
    - When we run out of usable circuit IDs on a channel, log only one
      warning for the whole channel, and describe how many circuits
      there were on the channel. Fixes part of ticket 11553.

  o Minor features (security, backport from 0.2.5.4-alpha):
    - Decrease the lower limit of MaxMemInCellQueues to 256 MBytes (but
      leave the default at 8GBytes), to better support Raspberry Pi
      users. Fixes bug 9686; bugfix on 0.2.4.14-alpha.

  o Documentation (backport from 0.2.5.4-alpha):
    - Correctly document that we search for a system torrc file before
      looking in ~/.torrc. Fixes documentation side of 9213; bugfix on
      0.2.3.18-rc.


Changes in version 0.2.4.21 - 2014-02-28
  Tor 0.2.4.21 further improves security against potential adversaries who
  find breaking 1024-bit crypto doable, and backports several stability
  and robustness patches from the 0.2.5 branch.

  o Major features (client security):
    - When we choose a path for a 3-hop circuit, make sure it contains
      at least one relay that supports the NTor circuit extension
      handshake. Otherwise, there is a chance that we're building
      a circuit that's worth attacking by an adversary who finds
      breaking 1024-bit crypto doable, and that chance changes the game
      theory. Implements ticket 9777.

  o Major bugfixes:
    - Do not treat streams that fail with reason
      END_STREAM_REASON_INTERNAL as indicating a definite circuit failure,
      since it could also indicate an ENETUNREACH connection error. Fixes
      part of bug 10777; bugfix on 0.2.4.8-alpha.

  o Code simplification and refactoring:
    - Remove data structures which were introduced to implement the
      CellStatistics option: they are now redundant with the new timestamp
      field in the regular packed_cell_t data structure, which we did
      in 0.2.4.18-rc in order to resolve bug 9093. Resolves ticket 10870.

  o Minor features:
    - Always clear OpenSSL bignums before freeing them -- even bignums
      that don't contain secrets. Resolves ticket 10793. Patch by
      Florent Daigniere.
    - Build without warnings under clang 3.4. (We have some macros that
      define static functions only some of which will get used later in
      the module. Starting with clang 3.4, these give a warning unless the
      unused attribute is set on them.) Resolves ticket 10904.
    - Update geoip and geoip6 files to the February 7 2014 Maxmind
      GeoLite2 Country database.

  o Minor bugfixes:
    - Set the listen() backlog limit to the largest actually supported
      on the system, not to the value in a header file. Fixes bug 9716;
      bugfix on every released Tor.
    - Treat ENETUNREACH, EACCES, and EPERM connection failures at an
      exit node as a NOROUTE error, not an INTERNAL error, since they
      can apparently happen when trying to connect to the wrong sort
      of netblocks. Fixes part of bug 10777; bugfix on 0.1.0.1-rc.
    - Fix build warnings about missing "a2x" comment when building the
      manpages from scratch on OpenBSD; OpenBSD calls it "a2x.py".
      Fixes bug 10929; bugfix on 0.2.2.9-alpha. Patch from Dana Koch.
    - Avoid a segfault on SIGUSR1, where we had freed a connection but did
      not entirely remove it from the connection lists. Fixes bug 9602;
      bugfix on 0.2.4.4-alpha.
    - Fix a segmentation fault in our benchmark code when running with
      Fedora's OpenSSL package, or any other OpenSSL that provides
      ECDH but not P224. Fixes bug 10835; bugfix on 0.2.4.8-alpha.
    - Turn "circuit handshake stats since last time" log messages into a
      heartbeat message. Fixes bug 10485; bugfix on 0.2.4.17-rc.

  o Documentation fixes:
    - Document that all but one DirPort entry must have the NoAdvertise
      flag set. Fixes bug 10470; bugfix on 0.2.3.3-alpha / 0.2.3.16-alpha.


Changes in version 0.2.4.20 - 2013-12-22
  Tor 0.2.4.20 fixes potentially poor random number generation for users
  who 1) use OpenSSL 1.0.0 or later, 2) set "HardwareAccel 1" in their
  torrc file, 3) have "Sandy Bridge" or "Ivy Bridge" Intel processors,
  and 4) have no state file in their DataDirectory (as would happen on
  first start). Users who generated relay or hidden service identity
  keys in such a situation should discard them and generate new ones.

  This release also fixes a logic error that caused Tor clients to build
  many more preemptive circuits than they actually need.

  o Major bugfixes:
    - Do not allow OpenSSL engines to replace the PRNG, even when
      HardwareAccel is set. The only default builtin PRNG engine uses
      the Intel RDRAND instruction to replace the entire PRNG, and
      ignores all attempts to seed it with more entropy. That's
      cryptographically stupid: the right response to a new alleged
      entropy source is never to discard all previously used entropy
      sources. Fixes bug 10402; works around behavior introduced in
      OpenSSL 1.0.0. Diagnosis and investigation thanks to "coderman"
      and "rl1987".
    - Fix assertion failure when AutomapHostsOnResolve yields an IPv6
      address. Fixes bug 10465; bugfix on 0.2.4.7-alpha.
    - Avoid launching spurious extra circuits when a stream is pending.
      This fixes a bug where any circuit that _wasn't_ unusable for new
      streams would be treated as if it were, causing extra circuits to
      be launched. Fixes bug 10456; bugfix on 0.2.4.12-alpha.

  o Minor bugfixes:
    - Avoid a crash bug when starting with a corrupted microdescriptor
      cache file. Fixes bug 10406; bugfix on 0.2.2.6-alpha.
    - If we fail to dump a previously cached microdescriptor to disk, avoid
      freeing duplicate data later on. Fixes bug 10423; bugfix on
      0.2.4.13-alpha. Spotted by "bobnomnom".


Changes in version 0.2.4.19 - 2013-12-11
  The Tor 0.2.4 release series is dedicated to the memory of Aaron Swartz
  (1986-2013). Aaron worked on diverse projects including helping to guide
  Creative Commons, playing a key role in stopping SOPA/PIPA, bringing
  transparency to the U.S government's PACER documents, and contributing
  design and development for Tor and Tor2Web. Aaron was one of the latest
  martyrs in our collective fight for civil liberties and human rights,
  and his death is all the more painful because he was one of us.

  Tor 0.2.4.19, the first stable release in the 0.2.4 branch, features
  a new circuit handshake and link encryption that use ECC to provide
  better security and efficiency; makes relays better manage circuit
  creation requests; uses "directory guards" to reduce client enumeration
  risks; makes bridges collect and report statistics about the pluggable
  transports they support; cleans up and improves our geoip database;
  gets much closer to IPv6 support for clients, bridges, and relays; makes
  directory authorities use measured bandwidths rather than advertised
  ones when computing flags and thresholds; disables client-side DNS
  caching to reduce tracking risks; and fixes a big bug in bridge
  reachability testing. This release introduces two new design
  abstractions in the code: a new "channel" abstraction between circuits
  and or_connections to allow for implementing alternate relay-to-relay
  transports, and a new "circuitmux" abstraction storing the queue of
  circuits for a channel. The release also includes many stability,
  security, and privacy fixes.

  o Major features (new circuit handshake):
    - Tor now supports a new circuit extension handshake designed by Ian
      Goldberg, Douglas Stebila, and Berkant Ustaoglu. Our original
      circuit extension handshake, later called "TAP", was a bit slow
      (especially on the relay side), had a fragile security proof, and
      used weaker keys than we'd now prefer. The new circuit handshake
      uses Dan Bernstein's "curve25519" elliptic-curve Diffie-Hellman
      function, making it significantly more secure than the older
      handshake, and significantly faster. Tor can use one of two built-in
      pure-C curve25519-donna implementations by Adam Langley, or it
      can link against the "nacl" library for a tuned version if present.

      The built-in version is very fast for 64-bit systems when building
      with GCC. The built-in 32-bit version is still faster than the
      old TAP protocol, but using libnacl is better on most such hosts.

      Implements proposal 216; closes ticket 7202.

  o Major features (better link encryption):
    - Relays can now enable the ECDHE TLS ciphersuites when available
      and appropriate. These ciphersuites let us negotiate forward-secure
      TLS secret keys more safely and more efficiently than with our
      previous use of Diffie-Hellman modulo a 1024-bit prime. By default,
      public relays prefer the (faster) P224 group, and bridges prefer
      the (more common) P256 group; you can override this with the
      TLSECGroup option.

      This feature requires clients running 0.2.3.17-beta or later,
      and requires both sides to be running OpenSSL 1.0.0 or later
      with ECC support. OpenSSL 1.0.1, with the compile-time option
      "enable-ec_nistp_64_gcc_128", is highly recommended.

      Implements the relay side of proposal 198; closes ticket 7200.

    - Re-enable TLS 1.1 and 1.2 when built with OpenSSL 1.0.1e or later.
      Resolves ticket 6055. (OpenSSL before 1.0.1 didn't have TLS 1.1 or
      1.2, and OpenSSL from 1.0.1 through 1.0.1d had bugs that prevented
      renegotiation from working with TLS 1.1 or 1.2, so we had disabled
      them to solve bug 6033.)

  o Major features (relay performance):
    - Instead of limiting the number of queued onionskins (aka circuit
      create requests) to a fixed, hard-to-configure number, we limit
      the size of the queue based on how many we expect to be able to
      process in a given amount of time. We estimate the time it will
      take to process an onionskin based on average processing time
      of previous onionskins. Closes ticket 7291. You'll never have to
      configure MaxOnionsPending again.
    - Relays process the new "NTor" circuit-level handshake requests
      with higher priority than the old "TAP" circuit-level handshake
      requests. We still process some TAP requests to not totally starve
      0.2.3 clients when NTor becomes popular. A new consensus parameter
      "NumNTorsPerTAP" lets us tune the balance later if we need to.
      Implements ticket 9574.

  o Major features (client bootstrapping resilience):
    - Add a new "FallbackDir" torrc option to use when we can't use
      a directory mirror from the consensus (either because we lack a
      consensus, or because they're all down). Currently, all authorities
      are fallbacks by default, and there are no other default fallbacks,
      but that will change. This option will allow us to give clients a
      longer list of servers to try to get a consensus from when first
      connecting to the Tor network, and thereby reduce load on the
      directory authorities. Implements proposal 206, "Preconfigured
      directory sources for bootstrapping". We also removed the old
      "FallbackNetworkstatus" option, since we never got it working well
      enough to use it. Closes bug 572.
    - If we have no circuits open, use a relaxed timeout (the
      95th-percentile cutoff) until a circuit succeeds. This heuristic
      should allow Tor to succeed at building circuits even when the
      network connection drastically changes. Should help with bug 3443.

  o Major features (use of guards):
    - Support directory guards (proposal 207): when possible, clients now
      use their entry guards for non-anonymous directory requests. This
      can help prevent client enumeration. Note that this behavior only
      works when we have a usable consensus directory, and when options
      about what to download are more or less standard. In the future we
      should re-bootstrap from our guards, rather than re-bootstrapping
      from the preconfigured list of directory sources that ships with
      Tor. Resolves ticket 6526.
    - Raise the default time that a client keeps an entry guard from
      "1-2 months" to "2-3 months", as suggested by Tariq Elahi's WPES
      2012 paper. (We would make it even longer, but we need better client
      load balancing first.) Also, make the guard lifetime controllable
      via a new GuardLifetime torrc option and a GuardLifetime consensus
      parameter. Start of a fix for bug 8240; bugfix on 0.1.1.11-alpha.

  o Major features (bridges with pluggable transports):
    - Bridges now report the pluggable transports they support to the
      bridge authority, so it can pass the supported transports on to
      bridgedb and/or eventually do reachability testing. Implements
      ticket 3589.
    - Automatically forward the TCP ports of pluggable transport
      proxies using tor-fw-helper if PortForwarding is enabled. Implements
      ticket 4567.

  o Major features (geoip database):
    - Maxmind began labelling Tor relays as being in country "A1",
      which breaks by-country node selection inside Tor. Now we use a
      script to replace "A1" ("Anonymous Proxy") entries in our geoip
      file with real country codes. This script fixes about 90% of "A1"
      entries automatically and uses manual country code assignments to
      fix the remaining 10%. See src/config/README.geoip for details.
      Fixes bug 6266.
    - Add GeoIP database for IPv6 addresses. The new config option
      is GeoIPv6File.
    - Update to the October 2 2013 Maxmind GeoLite Country database.

  o Major features (IPv6):
    - Clients who set "ClientUseIPv6 1" may connect to entry nodes over
      IPv6. Set "ClientPreferIPv6ORPort 1" to make this even more likely
      to happen. Implements ticket 5535.
    - All kind of relays, not just bridges, can now advertise an IPv6
      OR port. Implements ticket 6362.
    - Relays can now exit to IPv6 addresses: make sure that you have IPv6
      connectivity, then set the IPv6Exit flag to 1. Also make sure your
      exit policy reads as you would like: the address * applies to all
      address families, whereas *4 is IPv4 address only, and *6 is IPv6
      addresses only. On the client side, you'll need to wait for enough
      exits to support IPv6, apply the "IPv6Traffic" flag to a SocksPort,
      and use Socks5. Closes ticket 5547, implements proposal 117 as
      revised in proposal 208.
    - Bridge authorities now accept IPv6 bridge addresses and include
      them in network status documents. Implements ticket 5534.
    - Directory authorities vote on IPv6 OR ports. Implements ticket 6363.

  o Major features (directory authorities):
    - Directory authorities now prefer using measured bandwidths to
      advertised ones when computing flags and thresholds. Resolves
      ticket 8273.
    - Directory authorities that vote measured bandwidths about more
      than a threshold number of relays now treat relays with
      unmeasured bandwidths as having bandwidth 0 when computing their
      flags. Resolves ticket 8435.
    - Directory authorities now support a new consensus method (17)
      where they cap the published bandwidth of relays for which
      insufficient bandwidth measurements exist. Fixes part of bug 2286.
    - Directory authorities that set "DisableV2DirectoryInfo_ 1" no longer
      serve any v2 directory information. Now we can test disabling the
      old deprecated v2 directory format, and see whether doing so has
      any effect on network load. Begins to fix bug 6783.

  o Major features (build and portability):
    - Switch to a nonrecursive Makefile structure. Now instead of each
      Makefile.am invoking other Makefile.am's, there is a master
      Makefile.am that includes the others. This change makes our build
      process slightly more maintainable, and improves parallelism for
      building with make -j. Original patch by Stewart Smith; various
      fixes by Jim Meyering.
    - Where available, we now use automake's "silent" make rules by
      default, so that warnings are easier to spot. You can get the old
      behavior with "make V=1". Patch by Stewart Smith for ticket 6522.
    - Resume building correctly with MSVC and Makefile.nmake. This patch
      resolves numerous bugs and fixes reported by ultramage, including
      7305, 7308, 7309, 7310, 7312, 7313, 7315, 7316, and 7669.

  o Security features:
    - Switch to a completely time-invariant approach for picking nodes
      weighted by bandwidth. Our old approach would run through the
      part of the loop after it had made its choice slightly slower
      than it ran through the part of the loop before it had made its
      choice. Addresses ticket 6538.
    - Disable the use of Guard nodes when in Tor2WebMode. Guard usage
      by tor2web clients allows hidden services to identify tor2web
      clients through their repeated selection of the same rendezvous
      and introduction point circuit endpoints (their guards). Resolves
      ticket 6888.

  o Major bugfixes (relay denial of service):
    - When we have too much memory queued in circuits (according to a new
      MaxMemInCellQueues option), close the circuits that have the oldest
      queued cells, on the theory that those are most responsible for
      us running low on memory. This prevents us from running out of
      memory as a relay if circuits fill up faster than they can be
      drained. Fixes bugs 9063 and 9093; bugfix on the 54th commit of
      Tor. This bug is a further fix beyond bug 6252, whose fix was
      merged into 0.2.3.21-rc.
    - Reject bogus create and relay cells with 0 circuit ID or 0 stream
      ID: these could be used to create unexpected streams and circuits
      which would count as "present" to some parts of Tor but "absent"
      to others, leading to zombie circuits and streams or to a bandwidth
      denial-of-service. Fixes bug 7889; bugfix on every released version
      of Tor. Reported by "oftc_must_be_destroyed".
    - Avoid a bug where our response to TLS renegotiation under certain
      network conditions could lead to a busy-loop, with 100% CPU
      consumption. Fixes bug 5650; bugfix on 0.2.0.16-alpha.

  o Major bugfixes (asserts, crashes, leaks):
    - Prevent the get_freelists() function from running off the end of
      the list of freelists if it somehow gets an unrecognized
      allocation. Fixes bug 8844; bugfix on 0.2.0.16-alpha. Reported by
      eugenis.
    - Avoid a memory leak where we would leak a consensus body when we
      find that a consensus which we couldn't previously verify due to
      missing certificates is now verifiable. Fixes bug 8719; bugfix
      on 0.2.0.10-alpha.
    - If we are unable to save a microdescriptor to the journal, do not
      drop it from memory and then reattempt downloading it. Fixes bug
      9645; bugfix on 0.2.2.6-alpha.
    - Fix an assertion failure that would occur when disabling the
      ORPort setting on a running Tor process while accounting was
      enabled. Fixes bug 6979; bugfix on 0.2.2.18-alpha.
    - Avoid an assertion failure on OpenBSD (and perhaps other BSDs)
      when an exit connection with optimistic data succeeds immediately
      rather than returning EINPROGRESS. Fixes bug 9017; bugfix on
      0.2.3.1-alpha.
    - Fix a memory leak that would occur whenever a configuration
      option changed. Fixes bug 8718; bugfix on 0.2.3.3-alpha.

  o Major bugfixes (relay rate limiting):
    - When a TLS write is partially successful but incomplete, remember
      that the flushed part has been flushed, and notice that bytes were
      actually written. Reported and fixed pseudonymously. Fixes bug 7708;
      bugfix on Tor 0.1.0.5-rc.
    - Raise the default BandwidthRate/BandwidthBurst values from 5MB/10MB
      to 1GB/1GB. The previous defaults were intended to be "basically
      infinite", but it turns out they're now limiting our 100mbit+
      relays and bridges. Fixes bug 6605; bugfix on 0.2.0.10-alpha (the
      last time we raised it).
    - No longer stop reading or writing on cpuworker connections when
      our rate limiting buckets go empty. Now we should handle circuit
      handshake requests more promptly. Resolves bug 9731.

  o Major bugfixes (client-side privacy):
    - When we mark a circuit as unusable for new circuits, have it
      continue to be unusable for new circuits even if MaxCircuitDirtiness
      is increased too much at the wrong time, or the system clock jumps
      backwards. Fixes bug 6174; bugfix on 0.0.2pre26.
    - If ClientDNSRejectInternalAddresses ("do not believe DNS queries
      which have resolved to internal addresses") is set, apply that
      rule to IPv6 as well. Fixes bug 8475; bugfix on 0.2.0.7-alpha.
    - When an exit relay rejects a stream with reason "exit policy", but
      we only know an exit policy summary (e.g. from the microdesc
      consensus) for it, do not mark the relay as useless for all exiting.
      Instead, mark just the circuit as unsuitable for that particular
      address. Fixes part of bug 7582; bugfix on 0.2.3.2-alpha.

  o Major bugfixes (stream isolation):
    - Allow applications to get proper stream isolation with
      IsolateSOCKSAuth. Many SOCKS5 clients that want to offer
      username/password authentication also offer "no authentication". Tor
      had previously preferred "no authentication", so the applications
      never actually sent Tor their auth details. Now Tor selects
      username/password authentication if it's offered. You can disable
      this behavior on a per-SOCKSPort basis via PreferSOCKSNoAuth. Fixes
      bug 8117; bugfix on 0.2.3.3-alpha.
    - Follow the socks5 protocol when offering username/password
      authentication. The fix for bug 8117 exposed this bug, and it
      turns out real-world applications like Pidgin do care. Bugfix on
      0.2.3.2-alpha; fixes bug 8879.

  o Major bugfixes (client circuit building):
    - Alter circuit build timeout measurement to start at the point
      where we begin the CREATE/CREATE_FAST step (as opposed to circuit
      initialization). This should make our timeout measurements more
      uniform. Previously, we were sometimes including ORconn setup time
      in our circuit build time measurements. Should resolve bug 3443.
    - If the circuit build timeout logic is disabled (via the consensus,
      or because we are an authority), then don't build testing circuits.
      Fixes bug 9657; bugfix on 0.2.2.14-alpha.

  o Major bugfixes (client-side DNS):
    - Turn off the client-side DNS cache by default. Updating and using
      the DNS cache is now configurable on a per-client-port
      level. SOCKSPort, DNSPort, etc lines may now contain
      {No,}Cache{IPv4,IPv6,}DNS lines to indicate that we shouldn't
      cache these types of DNS answers when we receive them from an
      exit node in response to an application request on this port, and
      {No,}UseCached{IPv4,IPv6,DNS} lines to indicate that if we have
      cached DNS answers of these types, we shouldn't use them. It's
      potentially risky to use cached DNS answers at the client, since
      doing so can indicate to one exit what answers we've gotten
      for DNS lookups in the past. With IPv6, this becomes especially
      problematic. Using cached DNS answers for requests on the same
      circuit would present less linkability risk, since all traffic
      on a circuit is already linkable, but it would also provide
      little performance benefit: the exit node caches DNS replies
      too. Implements a simplified version of Proposal 205. Implements
      ticket 7570.

  o Major bugfixes (hidden service privacy):
    - Limit hidden service descriptors to at most ten introduction
      points, to slow one kind of guard enumeration. Fixes bug 9002;
      bugfix on 0.1.1.11-alpha.

  o Major bugfixes (directory fetching):
    - If the time to download the next old-style networkstatus is in
      the future, do not decline to consider whether to download the
      next microdescriptor networkstatus. Fixes bug 9564; bugfix on
      0.2.3.14-alpha.
    - We used to always request authority certificates by identity digest,
      meaning we'd get the newest one even when we wanted one with a
      different signing key. Then we would complain about being given
      a certificate we already had, and never get the one we really
      wanted. Now we use the "fp-sk/" resource as well as the "fp/"
      resource to request the one we want. Fixes bug 5595; bugfix on
      0.2.0.8-alpha.

  o Major bugfixes (bridge reachability):
    - Bridges now send AUTH_CHALLENGE cells during their v3 handshakes;
      previously they did not, which prevented them from receiving
      successful connections from relays for self-test or bandwidth
      testing. Also, when a relay is extending a circuit to a bridge,
      it needs to send a NETINFO cell, even when the bridge hasn't sent
      an AUTH_CHALLENGE cell. Fixes bug 9546; bugfix on 0.2.3.6-alpha.

  o Major bugfixes (control interface):
    - When receiving a new configuration file via the control port's
      LOADCONF command, do not treat the defaults file as absent.
      Fixes bug 9122; bugfix on 0.2.3.9-alpha.

  o Major bugfixes (directory authorities):
    - Stop marking every relay as having been down for one hour every
      time we restart a directory authority. These artificial downtimes
      were messing with our Stable and Guard flag calculations. Fixes
      bug 8218 (introduced by the fix for 1035). Bugfix on 0.2.2.23-alpha.
    - When computing directory thresholds, ignore any rejected-as-sybil
      nodes during the computation so that they can't influence Fast,
      Guard, etc. (We should have done this for proposal 109.) Fixes
      bug 8146.
    - When marking a node as a likely sybil, reset its uptime metrics
      to zero, so that it cannot time towards getting marked as Guard,
      Stable, or HSDir. (We should have done this for proposal 109.) Fixes
      bug 8147.
    - Fix a bug in the voting algorithm that could yield incorrect results
      when a non-naming authority declared too many flags. Fixes bug 9200;
      bugfix on 0.2.0.3-alpha.

  o Internal abstraction features:
    - Introduce new channel_t abstraction between circuits and
      or_connection_t to allow for implementing alternate OR-to-OR
      transports. A channel_t is an abstract object which can either be a
      cell-bearing channel, which is responsible for authenticating and
      handshaking with the remote OR and transmitting cells to and from
      it, or a listening channel, which spawns new cell-bearing channels
      at the request of remote ORs. Implements part of ticket 6465.
    - Make a channel_tls_t subclass of channel_t, adapting it to the
      existing or_connection_t code. The V2/V3 protocol handshaking
      code which formerly resided in command.c has been moved below the
      channel_t abstraction layer and may be found in channeltls.c now.
      Implements the rest of ticket 6465.
    - Introduce new circuitmux_t storing the queue of circuits for
      a channel; this encapsulates and abstracts the queue logic and
      circuit selection policy, and allows the latter to be overridden
      easily by switching out a policy object. The existing EWMA behavior
      is now implemented as a circuitmux_policy_t. Resolves ticket 6816.

  o New build requirements:
    - Tor now requires OpenSSL 0.9.8 or later. OpenSSL 1.0.0 or later is
      strongly recommended.
    - Tor maintainers now require Automake version 1.9 or later to build
      Tor from the Git repository. (Automake is not required when building
      from a source distribution.)

  o Minor features (protocol):
    - No longer include the "opt" prefix when generating routerinfos
      or v2 directories: it has been needless since Tor 0.1.2. Closes
      ticket 5124.
    - Reject EXTEND cells sent to nonexistent streams. According to the
      spec, an EXTEND cell sent to _any_ nonzero stream ID is invalid, but
      we were only checking for stream IDs that were currently in use.
      Found while hunting for more instances of bug 6271. Bugfix on
      0.0.2pre8, which introduced incremental circuit construction.
    - Tor relays and clients now support a better CREATE/EXTEND cell
      format, allowing the sender to specify multiple address, identity,
      and handshake types. Implements Robert Ransom's proposal 200;
      closes ticket 7199.
    - Reject as invalid most directory objects containing a NUL.
      Belt-and-suspender fix for bug 8037.

  o Minor features (security):
    - Clear keys and key-derived material left on the stack in
      rendservice.c and rendclient.c. Check return value of
      crypto_pk_write_private_key_to_string() in rend_service_load_keys().
      These fixes should make us more forward-secure against cold-boot
      attacks and the like. Fixes bug 2385.
    - Use our own weak RNG when we need a weak RNG. Windows's rand() and
      Irix's random() only return 15 bits; Solaris's random() returns more
      bits but its RAND_MAX says it only returns 15, and so on. Motivated
      by the fix for bug 7801; bugfix on 0.2.2.20-alpha.

  o Minor features (control protocol):
    - Add a "GETINFO signal/names" control port command. Implements
      ticket 3842.
    - Provide default values for all options via "GETINFO config/defaults".
      Implements ticket 4971.
    - Allow an optional $ before the node identity digest in the
      controller command GETINFO ns/id/<identity>, for consistency with
      md/id/<identity> and desc/id/<identity>. Resolves ticket 7059.
    - Add CACHED keyword to ADDRMAP events in the control protocol
      to indicate whether a DNS result will be cached or not. Resolves
      ticket 8596.
    - Generate bootstrapping status update events correctly when fetching
      microdescriptors. Fixes bug 9927.

  o Minor features (path selection):
    - When deciding whether we have enough descriptors to build circuits,
      instead of looking at raw relay counts, look at which fraction
      of (bandwidth-weighted) paths we're able to build. This approach
      keeps clients from building circuits if their paths are likely to
      stand out statistically. The default fraction of paths needed is
      taken from the consensus directory; you can override it with the
      new PathsNeededToBuildCircuits option. Fixes ticket 5956.
    - When any country code is listed in ExcludeNodes or ExcludeExitNodes,
      and we have GeoIP information, also exclude all nodes with unknown
      countries "??" and "A1". This behavior is controlled by the
      new GeoIPExcludeUnknown option: you can make such nodes always
      excluded with "GeoIPExcludeUnknown 1", and disable the feature
      with "GeoIPExcludeUnknown 0". Setting "GeoIPExcludeUnknown auto"
      gets you the default behavior. Implements feature 7706.

  o Minor features (hidden services):
    - Improve circuit build timeout handling for hidden services.
      In particular: adjust build timeouts more accurately depending
      upon the number of hop-RTTs that a particular circuit type
      undergoes. Additionally, launch intro circuits in parallel
      if they timeout, and take the first one to reply as valid.
    - The Tor client now ignores sub-domain components of a .onion
      address. This change makes HTTP "virtual" hosting
      possible: http://foo.aaaaaaaaaaaaaaaa.onion/ and
      http://bar.aaaaaaaaaaaaaaaa.onion/ can be two different websites
      hosted on the same hidden service. Implements proposal 204.
    - Enable Tor to read configuration, state, and key information from
      a FIFO. Previously Tor would only read from files with a positive
      stat.st_size. Code from meejah; fixes bug 6044.

  o Minor features (clients):
    - Teach bridge-using clients to avoid 0.2.2.x bridges when making
      microdescriptor-related dir requests, and only fall back to normal
      descriptors if none of their bridges can handle microdescriptors
      (as opposed to the fix in ticket 4013, which caused them to fall
      back to normal descriptors if *any* of their bridges preferred
      them). Resolves ticket 4994.
    - Tweak tor-fw-helper to accept an arbitrary amount of arbitrary
      TCP ports to forward. In the past it only accepted two ports:
      the ORPort and the DirPort.

  o Minor features (protecting client timestamps):
    - Clients no longer send timestamps in their NETINFO cells. These were
      not used for anything, and they provided one small way for clients
      to be distinguished from each other as they moved from network to
      network or behind NAT. Implements part of proposal 222.
    - Clients now round timestamps in INTRODUCE cells down to the nearest
      10 minutes. If a new Support022HiddenServices option is set to 0, or
      if it's set to "auto" and the feature is disabled in the consensus,
      the timestamp is sent as 0 instead. Implements part of proposal 222.
    - Stop sending timestamps in AUTHENTICATE cells. This is not such
      a big deal from a security point of view, but it achieves no actual
      good purpose, and isn't needed. Implements part of proposal 222.
    - Reduce down accuracy of timestamps in hidden service descriptors.
      Implements part of proposal 222.

  o Minor features (bridges):
    - Make bridge relays check once a minute for whether their IP
      address has changed, rather than only every 15 minutes. Resolves
      bugs 1913 and 1992.
    - Bridge statistics now count bridge clients connecting over IPv6:
      bridge statistics files now list "bridge-ip-versions" and
      extra-info documents list "geoip6-db-digest". The control protocol
      "CLIENTS_SEEN" and "ip-to-country" queries now support IPv6. Initial
      implementation by "shkoo", addressing ticket 5055.
    - Add a new torrc option "ServerTransportListenAddr" to let bridge
      operators select the address where their pluggable transports will
      listen for connections. Resolves ticket 7013.
    - Randomize the lifetime of our SSL link certificate, so censors can't
      use the static value for filtering Tor flows. Resolves ticket 8443;
      related to ticket 4014 which was included in 0.2.2.33.

  o Minor features (relays):
    - Option OutboundBindAddress can be specified multiple times and
      accepts IPv6 addresses. Resolves ticket 6876.

  o Minor features (IPv6, client side):
    - AutomapHostsOnResolve now supports IPv6 addresses. By default, we
      prefer to hand out virtual IPv6 addresses, since there are more of
      them and we can't run out. To override this behavior and make IPv4
      addresses preferred, set NoPreferIPv6Automap on whatever SOCKSPort
      or DNSPort you're using for resolving. Implements ticket 7571.
    - AutomapHostsOnResolve responses are now randomized, to avoid
      annoying situations where Tor is restarted and applications
      connect to the wrong addresses.
    - Never try more than 1000 times to pick a new virtual address when
      AutomapHostsOnResolve is set. That's good enough so long as we
      aren't close to handing out our entire virtual address space;
      if you're getting there, it's best to switch to IPv6 virtual
      addresses anyway.

  o Minor features (IPv6, relay/authority side):
    - New config option "AuthDirHasIPv6Connectivity 1" that directory
      authorities should set if they have IPv6 connectivity and want to
      do reachability tests for IPv6 relays. Implements feature 5974.
    - A relay with an IPv6 OR port now sends that address in NETINFO
      cells (in addition to its other address). Implements ticket 6364.

  o Minor features (directory authorities):
    - Directory authorities no long accept descriptors for any version of
      Tor before 0.2.2.35, or for any 0.2.3 release before 0.2.3.10-alpha.
      These versions are insecure, unsupported, or both. Implements
      ticket 6789.
    - When directory authorities are computing thresholds for flags,
      never let the threshold for the Fast flag fall below 4096
      bytes. Also, do not consider nodes with extremely low bandwidths
      when deciding thresholds for various directory flags. This change
      should raise our threshold for Fast relays, possibly in turn
      improving overall network performance; see ticket 1854. Resolves
      ticket 8145.
    - Directory authorities now include inside each vote a statement of
      the performance thresholds they used when assigning flags.
      Implements ticket 8151.
    - Add an "ignoring-advertised-bws" boolean to the flag-threshold lines
      in directory authority votes to describe whether they have enough
      measured bandwidths to ignore advertised (relay descriptor)
      bandwidth claims. Resolves ticket 8711.

  o Minor features (path bias detection):
    - Path Use Bias: Perform separate accounting for successful circuit
      use. Keep separate statistics on stream attempt rates versus stream
      success rates for each guard. Provide configurable thresholds to
      determine when to emit log messages or disable use of guards that
      fail too many stream attempts. Resolves ticket 7802.
    - Create three levels of Path Bias log messages, as opposed to just
      two. These are configurable via consensus as well as via the torrc
      options PathBiasNoticeRate, PathBiasWarnRate, PathBiasExtremeRate.
      The default values are 0.70, 0.50, and 0.30 respectively.
    - Separate the log message levels from the decision to drop guards,
      which also is available via torrc option PathBiasDropGuards.
      PathBiasDropGuards still defaults to 0 (off).
    - Deprecate PathBiasDisableRate in favor of PathBiasDropGuards
      in combination with PathBiasExtremeRate.
    - Increase the default values for PathBiasScaleThreshold and
      PathBiasCircThreshold from (200, 20) to (300, 150).
    - Add in circuit usage accounting to path bias. If we try to use a
      built circuit but fail for any reason, it counts as path bias.
      Certain classes of circuits where the adversary gets to pick your
      destination node are exempt from this accounting. Usage accounting
      can be specifically disabled via consensus parameter or torrc.
    - Convert all internal path bias state to double-precision floating
      point, to avoid roundoff error and other issues.
    - Only record path bias information for circuits that have completed
      *two* hops. Assuming end-to-end tagging is the attack vector, this
      makes us more resilient to ambient circuit failure without any
      detection capability loss.

  o Minor features (build):
    - Tor now builds correctly on Bitrig, an OpenBSD fork. Patch from
      dhill. Resolves ticket 6982.
    - Compile on win64 using mingw64. Fixes bug 7260; patches from
      "yayooo".
    - Work correctly on Unix systems where EAGAIN and EWOULDBLOCK are
      separate error codes; or at least, don't break for that reason.
      Fixes bug 7935. Reported by "oftc_must_be_destroyed".

  o Build improvements (autotools):
    - Warn if building on a platform with an unsigned time_t: there
      are too many places where Tor currently assumes that time_t can
      hold negative values. We'd like to fix them all, but probably
      some will remain.
    - Do not report status verbosely from autogen.sh unless the -v flag
      is specified. Fixes issue 4664. Patch from Onizuka.
    - Detect and reject attempts to build Tor with threading support
      when OpenSSL has been compiled without threading support.
      Fixes bug 6673.
    - Try to detect if we are ever building on a platform where
      memset(...,0,...) does not set the value of a double to 0.0. Such
      platforms are permitted by the C standard, though in practice
      they're pretty rare (since IEEE 754 is nigh-ubiquitous). We don't
      currently support them, but it's better to detect them and fail
      than to perform erroneously.
    - We no longer warn so much when generating manpages from their
      asciidoc source.
    - Use Ville Laurikari's implementation of AX_CHECK_SIGN() to determine
      the signs of types during autoconf. This is better than our old
      approach, which didn't work when cross-compiling.

  o Minor features (log messages, warnings):
    - Detect when we're running with a version of OpenSSL other than the
      one we compiled with. This conflict has occasionally given people
      hard-to-track-down errors.
    - Warn users who run hidden services on a Tor client with
      UseEntryGuards disabled that their hidden services will be
      vulnerable to http://freehaven.net/anonbib/#hs-attack06 (the
      attack which motivated Tor to support entry guards in the first
      place). Resolves ticket 6889.
    - Warn when we are binding low ports when hibernation is enabled;
      previously we had warned when we were _advertising_ low ports with
      hibernation enabled. Fixes bug 7285; bugfix on 0.2.3.9-alpha.
    - Issue a warning when running with the bufferevents backend enabled.
      It's still not stable, and people should know that they're likely
      to hit unexpected problems. Closes ticket 9147.

  o Minor features (log messages, notices):
    - Refactor resolve_my_address() so it returns the method by which we
      decided our public IP address (explicitly configured, resolved from
      explicit hostname, guessed from interfaces, learned by gethostname).
      Now we can provide more helpful log messages when a relay guesses
      its IP address incorrectly (e.g. due to unexpected lines in
      /etc/hosts). Resolves ticket 2267.
    - Track how many "TAP" and "NTor" circuit handshake requests we get,
      and how many we complete, and log it every hour to help relay
      operators follow trends in network load. Addresses ticket 9658.

  o Minor features (log messages, diagnostics):
    - If we fail to free a microdescriptor because of bug 7164, log
      the filename and line number from which we tried to free it.
    - We compute the overhead from passing onionskins back and forth to
      cpuworkers, and report it when dumping statistics in response to
      SIGUSR1. Supports ticket 7291.
    - Add another diagnostic to the heartbeat message: track and log
      overhead that TLS is adding to the data we write. If this is
      high, we are sending too little data to SSL_write at a time.
      Diagnostic for bug 7707.
    - Log packaged cell fullness as part of the heartbeat message.
      Diagnosis to try to determine the extent of bug 7743.
    - Add more detail to a log message about relaxed timeouts, to help
      track bug 7799.
    - When learning a fingerprint for a bridge, log its corresponding
      transport type. Implements ticket 7896.
    - Warn more aggressively when flushing microdescriptors to a
      microdescriptor cache fails, in an attempt to mitigate bug 8031,
      or at least make it more diagnosable.
    - Improve the log message when "Bug/attack: unexpected sendme cell
      from client" occurs, to help us track bug 8093.
    - Improve debugging output to help track down bug 8185 ("Bug:
      outgoing relay cell has n_chan==NULL. Dropping.")

  o Minor features (log messages, quieter bootstrapping):
    - Log fewer lines at level "notice" about our OpenSSL and Libevent
      versions and capabilities when everything is going right. Resolves
      part of ticket 6736.
    - Omit the first heartbeat log message, because it never has anything
      useful to say, and it clutters up the bootstrapping messages.
      Resolves ticket 6758.
    - Don't log about reloading the microdescriptor cache at startup. Our
      bootstrap warnings are supposed to tell the user when there's a
      problem, and our bootstrap notices say when there isn't. Resolves
      ticket 6759; bugfix on 0.2.2.6-alpha.
    - Don't log "I learned some more directory information" when we're
      reading cached directory information. Reserve it for when new
      directory information arrives in response to a fetch. Resolves
      ticket 6760.
    - Don't complain about bootstrapping problems while hibernating.
      These complaints reflect a general code problem, but not one
      with any problematic effects (no connections are actually
      opened). Fixes part of bug 7302; bugfix on 0.2.3.2-alpha.

  o Minor features (testing):
    - In our testsuite, create temporary directories with a bit more
      entropy in their name to make name collisions less likely. Fixes
      bug 8638.
    - Add benchmarks for DH (1024-bit multiplicative group) and ECDH
      (P-256) Diffie-Hellman handshakes to src/or/bench.
    - Add benchmark functions to test onion handshake performance.

  o Renamed options:
    - The DirServer option is now DirAuthority, for consistency with
      current naming patterns. You can still use the old DirServer form.

  o Minor bugfixes (protocol):
    - Fix the handling of a TRUNCATE cell when it arrives while the
      circuit extension is in progress. Fixes bug 7947; bugfix on 0.0.7.1.
    - When a Tor client gets a "truncated" relay cell, the first byte of
      its payload specifies why the circuit was truncated. We were
      ignoring this 'reason' byte when tearing down the circuit, resulting
      in the controller not being told why the circuit closed. Now we
      pass the reason from the truncated cell to the controller. Bugfix
      on 0.1.2.3-alpha; fixes bug 7039.
    - Fix a misframing issue when reading the version numbers in a
      VERSIONS cell. Previously we would recognize [00 01 00 02] as
      'version 1, version 2, and version 0x100', when it should have
      only included versions 1 and 2. Fixes bug 8059; bugfix on
      0.2.0.10-alpha. Reported pseudonymously.
    - Make the format and order of STREAM events for DNS lookups
      consistent among the various ways to launch DNS lookups. Fixes
      bug 8203; bugfix on 0.2.0.24-rc. Patch by "Desoxy".

  o Minor bugfixes (syscalls and disk interaction):
    - Always check the return values of functions fcntl() and
      setsockopt(). We don't believe these are ever actually failing in
      practice, but better safe than sorry. Also, checking these return
      values should please analysis tools like Coverity. Patch from
      'flupzor'. Fixes bug 8206; bugfix on all versions of Tor.
    - Avoid double-closing the listener socket in our socketpair()
      replacement (used on Windows) in the case where the addresses on
      our opened sockets don't match what we expected. Fixes bug 9400;
      bugfix on 0.0.2pre7. Found by Coverity.
    - Correctly store microdescriptors and extrainfo descriptors that
      include an internal NUL byte. Fixes bug 8037; bugfix on
      0.2.0.1-alpha. Bug reported by "cypherpunks".
    - If for some reason we fail to write a microdescriptor while
      rebuilding the cache, do not let the annotations from that
      microdescriptor linger in the cache file, and do not let the
      microdescriptor stay recorded as present in its old location.
      Fixes bug 9047; bugfix on 0.2.2.6-alpha.
    - Use direct writes rather than stdio when building microdescriptor
      caches, in an attempt to mitigate bug 8031, or at least make it
      less common.

  o Minor fixes (config options):
    - Warn and fail if a server is configured not to advertise any
      ORPorts at all. (We need *something* to put in our descriptor,
      or we just won't work.)
    - Behave correctly when the user disables LearnCircuitBuildTimeout
      but doesn't tell us what they would like the timeout to be. Fixes
      bug 6304; bugfix on 0.2.2.14-alpha.
    - Rename the (internal-use-only) UsingTestingNetworkDefaults option
      to start with a triple-underscore so the controller won't touch it.
      Patch by Meejah. Fixes bug 3155. Bugfix on 0.2.2.23-alpha.
    - Rename the (testing-use-only) _UseFilteringSSLBufferevents option
      so it doesn't start with _. Fixes bug 3155. Bugfix on 0.2.3.1-alpha.
    - When autodetecting the number of CPUs, use the number of available
      CPUs in preference to the number of configured CPUs. Inform the
      user if this reduces the number of available CPUs. Fixes bug 8002;
      bugfix on 0.2.3.1-alpha.
    - Command-line option "--version" implies "--quiet". Fixes bug 6997.
    - Make it an error when you set EntryNodes but disable UseGuardNodes,
      since it will (surprisingly to some users) ignore EntryNodes. Fixes
      bug 8180; bugfix on 0.2.3.11-alpha.
    - Avoid overflows when the user sets MaxCircuitDirtiness to a
      ridiculously high value, by imposing a (ridiculously high) 30-day
      maximum on MaxCircuitDirtiness.

  o Minor bugfixes (control protocol):
    - Stop sending a stray "(null)" in some cases for the server status
      "EXTERNAL_ADDRESS" controller event. Resolves bug 8200; bugfix
      on 0.1.2.6-alpha.
    - The ADDRMAP command can no longer generate an ill-formed error
      code on a failed MAPADDRESS. It now says "internal" rather than
      an English sentence fragment with spaces in the middle. Bugfix on
      Tor 0.2.0.19-alpha.

  o Minor bugfixes (clients / edges):
    - When we receive a RELAY_END cell with the reason DONE, or with no
      reason, before receiving a RELAY_CONNECTED cell, report the SOCKS
      status as "connection refused". Previously we reported these cases
      as success but then immediately closed the connection. Fixes bug
      7902; bugfix on 0.1.0.1-rc. Reported by "oftc_must_be_destroyed".
    - If the guard we choose first doesn't answer, we would try the
      second guard, but once we connected to the second guard we would
      abandon it and retry the first one, slowing down bootstrapping.
      The fix is to treat all our initially chosen guards as acceptable
      to use. Fixes bug 9946; bugfix on 0.1.1.11-alpha.
    - When choosing which stream on a formerly stalled circuit to wake
      first, make better use of the platform's weak RNG. Previously,
      we had been using the % ("modulo") operator to try to generate a
      1/N chance of picking each stream, but this behaves badly with
      many platforms' choice of weak RNG. Fixes bug 7801; bugfix on
      0.2.2.20-alpha.

  o Minor bugfixes (path bias detection):
    - If the state file's path bias counts are invalid (presumably from a
      buggy Tor prior to 0.2.4.10-alpha), make them correct. Also add
      additional checks and log messages to the scaling of Path Bias
      counts, in case there still are remaining issues with scaling.
      Should help resolve bug 8235.
    - Prevent rounding error in path bias counts when scaling
      them down, and use the correct scale factor default. Also demote
      some path bias related log messages down a level and make others
      less scary sounding. Fixes bug 6647. Bugfix on 0.2.3.17-beta.
    - Remove a source of rounding error during path bias count scaling;
      don't count cannibalized circuits as used for path bias until we
      actually try to use them; and fix a circuit_package_relay_cell()
      warning message about n_chan==NULL. Fixes bug 7802.
    - Paste the description for PathBias parameters from the man
      page into or.h, so the code documents them too. Fixes bug 7982;
      bugfix on 0.2.3.17-beta.

  o Minor bugfixes (relays):
    - Stop trying to resolve our hostname so often (e.g. every time we
      think about doing a directory fetch). Now we reuse the cached
      answer in some cases. Fixes bugs 1992 (bugfix on 0.2.0.20-rc)
      and 2410 (bugfix on 0.1.2.2-alpha).
    - When examining the list of network interfaces to find our address,
      do not consider non-running or disabled network interfaces. Fixes
      bug 9904; bugfix on 0.2.3.11-alpha. Patch from "hantwister".

  o Minor bugfixes (blocking resistance):
    - Only disable TLS session ticket support when running as a TLS
      server. Now clients will blend better with regular Firefox
      connections. Fixes bug 7189; bugfix on Tor 0.2.3.23-rc.

  o Minor bugfixes (IPv6):
    - Use square brackets around IPv6 addresses in numerous places
      that needed them, including log messages, HTTPS CONNECT proxy
      requests, TransportProxy statefile entries, and pluggable transport
      extra-info lines. Fixes bug 7011; patch by David Fifield.

  o Minor bugfixes (directory authorities):
    - Reject consensus votes with more than 64 known-flags. We aren't even
      close to that limit yet, and our code doesn't handle it correctly.
      Fixes bug 6833; bugfix on 0.2.0.1-alpha.
    - Correctly handle votes with more than 31 flags. Fixes bug 6853;
      bugfix on 0.2.0.3-alpha.

  o Minor bugfixes (memory leaks):
    - Avoid leaking memory if we fail to compute a consensus signature
      or we generate a consensus we can't parse. Bugfix on 0.2.0.5-alpha.
    - Fix a memory leak when receiving headers from an HTTPS proxy. Bugfix
      on 0.2.1.1-alpha; fixes bug 7816.
    - Fix a memory leak during safe-cookie controller authentication.
      Bugfix on 0.2.3.13-alpha; fixes bug 7816.
    - Free some more still-in-use memory at exit, to make hunting for
      memory leaks easier. Resolves bug 7029.

  o Minor bugfixes (code correctness):
    - Increase the width of the field used to remember a connection's
      link protocol version to two bytes. Harmless for now, since the
      only currently recognized versions are one byte long. Reported
      pseudonymously. Fixes bug 8062; bugfix on 0.2.0.10-alpha.
    - Fix a crash when debugging unit tests on Windows: deallocate a
      shared library with FreeLibrary, not CloseHandle. Fixes bug 7306;
      bugfix on 0.2.2.17-alpha. Reported by "ultramage".
    - When detecting the largest possible file descriptor (in order to
      close all file descriptors when launching a new program), actually
      use _SC_OPEN_MAX. The old code for doing this was very, very broken.
      Fixes bug 8209; bugfix on 0.2.3.1-alpha. Found by Coverity; this
      is CID 743383.
    - Avoid a crash if we fail to generate an extrainfo descriptor.
      Fixes bug 8208; bugfix on 0.2.3.16-alpha. Found by Coverity;
      this is CID 718634.
    - Avoid an off-by-one error when checking buffer boundaries when
      formatting the exit status of a pluggable transport helper.
      This is probably not an exploitable bug, but better safe than
      sorry. Fixes bug 9928; bugfix on 0.2.3.18-rc. Bug found by
      Pedro Ribeiro.
    - Get rid of a couple of harmless clang warnings, where we compared
      enums to ints. These warnings are newly introduced in clang 3.2.

  o Minor bugfixes (code cleanliness):
    - Avoid use of reserved identifiers in our C code. The C standard
      doesn't like us declaring anything that starts with an
      underscore, so let's knock it off before we get in trouble. Fix
      for bug 1031; bugfix on the first Tor commit.
    - Fix round_to_power_of_2() so it doesn't invoke undefined behavior
      with large values. This situation was untriggered, but nevertheless
      incorrect. Fixes bug 6831; bugfix on 0.2.0.1-alpha.
    - Fix an impossible buffer overrun in the AES unit tests. Fixes
      bug 8845; bugfix on 0.2.0.7-alpha. Found by eugenis.
    - Fix handling of rendezvous client authorization types over 8.
      Fixes bug 6861; bugfix on 0.2.1.5-alpha.
    - Remove a couple of extraneous semicolons that were upsetting the
      cparser library. Patch by Christian Grothoff. Fixes bug 7115;
      bugfix on 0.2.2.1-alpha.
    - When complaining about a client port on a public address, log
      which address we're complaining about. Fixes bug 4020; bugfix on
      0.2.3.3-alpha. Patch by Tom Fitzhenry.

  o Minor bugfixes (log messages, warnings):
    - If we encounter a write failure on a SOCKS connection before we
      finish our SOCKS handshake, don't warn that we closed the
      connection before we could send a SOCKS reply. Fixes bug 8427;
      bugfix on 0.1.0.1-rc.
    - Fix a directory authority warn caused when we have a large amount
      of badexit bandwidth. Fixes bug 8419; bugfix on 0.2.2.10-alpha.
    - Downgrade "Failed to hand off onionskin" messages to "debug"
      severity, since they're typically redundant with the "Your computer
      is too slow" messages. Fixes bug 7038; bugfix on 0.2.2.16-alpha.
    - Avoid spurious warnings when configuring multiple client ports of
      which only some are nonlocal. Previously, we had claimed that some
      were nonlocal when in fact they weren't. Fixes bug 7836; bugfix on
      0.2.3.3-alpha.

  o Minor bugfixes (log messages, other):
    - Fix log messages and comments to avoid saying "GMT" when we mean
      "UTC". Fixes bug 6113.
    - When rejecting a configuration because we were unable to parse a
      quoted string, log an actual error message. Fixes bug 7950; bugfix
      on 0.2.0.16-alpha.
    - Correctly recognize that [::1] is a loopback address. Fixes
      bug 8377; bugfix on 0.2.1.3-alpha.
    - Don't log inappropriate heartbeat messages when hibernating: a
      hibernating node is _expected_ to drop out of the consensus,
      decide it isn't bootstrapped, and so forth. Fixes bug 7302;
      bugfix on 0.2.3.1-alpha.
    - Eliminate several instances where we use "Nickname=ID" to refer to
      nodes in logs. Use "Nickname (ID)" instead. (Elsewhere, we still use
      "$ID=Nickname", which is also acceptable.) Fixes bug 7065. Bugfix
      on 0.2.3.21-rc.

  o Minor bugfixes (build):
    - Fix some bugs in tor-fw-helper-natpmp when trying to build and
      run it on Windows. More bugs likely remain. Patch from Gisle Vanem.
      Fixes bug 7280; bugfix on 0.2.3.1-alpha.

  o Documentation fixes:
    - Make the torify manpage no longer refer to tsocks; torify hasn't
      supported tsocks since 0.2.3.14-alpha.
    - Make the tor manpage no longer reference tsocks.
    - Fix the GeoIPExcludeUnknown documentation to refer to
      ExcludeExitNodes rather than the currently nonexistent
      ExcludeEntryNodes. Spotted by "hamahangi" on tor-talk.
    - Resolve a typo in torrc.sample.in. Fixes bug 6819; bugfix on
      0.2.3.14-alpha.
    - Say "KBytes" rather than "KB" in the man page (for various values
      of K), to further reduce confusion about whether Tor counts in
      units of memory or fractions of units of memory. Resolves ticket 7054.
    - Update tor-fw-helper.1.txt and tor-fw-helper.c to make option
      names match. Fixes bug 7768.
    - Fix the documentation of HeartbeatPeriod to say that the heartbeat
      message is logged at notice, not at info.
    - Clarify the usage and risks of setting the ContactInfo torrc line
      for your relay or bridge. Resolves ticket 9854.
    - Add anchors to the manpage so we can link to the html version of
      the documentation for specific options. Resolves ticket 9866.
    - Replace remaining references to DirServer in man page and
      log entries. Resolves ticket 10124.

  o Removed features:
    - Stop exporting estimates of v2 and v3 directory traffic shares
      in extrainfo documents. They were unneeded and sometimes inaccurate.
      Also stop exporting any v2 directory request statistics. Resolves
      ticket 5823.
    - Drop support for detecting and warning about versions of Libevent
      before 1.3e. Nothing reasonable ships with them any longer; warning
      the user about them shouldn't be needed. Resolves ticket 6826.
    - Now that all versions before 0.2.2.x are disallowed, we no longer
      need to work around their missing features. Remove a bunch of
      compatibility code.

  o Removed files:
    - The tor-tsocks.conf is no longer distributed or installed. We
      recommend that tsocks users use torsocks instead. Resolves
      ticket 8290.
    - Remove some of the older contents of doc/ as obsolete; move others
      to torspec.git. Fixes bug 8965.

  o Code simplification:
    - Avoid using character buffers when constructing most directory
      objects: this approach was unwieldy and error-prone. Instead,
      build smartlists of strings, and concatenate them when done.
    - Rename "isin" functions to "contains", for grammar. Resolves
      ticket 5285.
    - Rename Tor's logging function log() to tor_log(), to avoid conflicts
      with the natural logarithm function from the system libm. Resolves
      ticket 7599.
    - Start using OpenBSD's implementation of queue.h, so that we don't
      need to hand-roll our own pointer and list structures whenever we
      need them. (We can't rely on a sys/queue.h, since some operating
      systems don't have them, and the ones that do have them don't all
      present the same extensions.)
    - Start using OpenBSD's implementation of queue.h (originally by
      Niels Provos).
    - Enhance our internal sscanf replacement so that we can eliminate
      the last remaining uses of the system sscanf. (Though those uses
      of sscanf were safe, sscanf itself is generally error prone, so
      we want to eliminate when we can.) Fixes ticket 4195 and Coverity
      CID 448.
    - Replace all calls to snprintf() outside of src/ext with
      tor_snprintf(). Also remove the #define to replace snprintf with
      _snprintf on Windows; they have different semantics, and all of
      our callers should be using tor_snprintf() anyway. Fixes bug 7304.

  o Refactoring:
    - Add a wrapper function for the common "log a message with a
      rate-limit" case.
    - Split the onion.c file into separate modules for the onion queue
      and the different handshakes it supports.
    - Move the client-side address-map/virtual-address/DNS-cache code
      out of connection_edge.c into a new addressmap.c module.
    - Move the entry node code from circuitbuild.c to its own file.
    - Move the circuit build timeout tracking code from circuitbuild.c
      to its own file.
    - Source files taken from other packages now reside in src/ext;
      previously they were scattered around the rest of Tor.
    - Move the generic "config" code into a new file, and have "config.c"
      hold only torrc- and state-related code. Resolves ticket 6823.
    - Move the core of our "choose a weighted element at random" logic
      into its own function, and give it unit tests. Now the logic is
      testable, and a little less fragile too.
    - Move ipv6_preferred from routerinfo_t to node_t. Addresses bug 4620.
    - Move last_reachable and testing_since from routerinfo_t to node_t.
      Implements ticket 5529.
    - Add replaycache_t structure, functions and unit tests, then refactor
      rend_service_introduce() to be more clear to read, improve, debug,
      and test. Resolves bug 6177.

  o Removed code:
    - Remove some now-needless code that tried to aggressively flush
      OR connections as data was added to them. Since 0.2.0.1-alpha, our
      cell queue logic has saved us from the failure mode that this code
      was supposed to prevent. Removing this code will limit the number
      of baroque control flow paths through Tor's network logic. Reported
      pseudonymously on IRC. Fixes bug 6468; bugfix on 0.2.0.1-alpha.
    - Remove unused code for parsing v1 directories and "running routers"
      documents. Fixes bug 6887.
    - Remove the marshalling/unmarshalling code for sending requests to
      cpuworkers over a socket, and instead just send structs. The
      recipient will always be the same Tor binary as the sender, so
      any encoding is overkill.
    - Remove the testing_since field of node_t, which hasn't been used
      for anything since 0.2.0.9-alpha.
    - Finally remove support for malloc_good_size and malloc_usable_size.
      We had hoped that these functions would let us eke a little more
      memory out of our malloc implementation. Unfortunately, the only
      implementations that provided these functions are also ones that
      are already efficient about not overallocation: they never got us
      more than 7 or so bytes per allocation. Removing them saves us a
      little code complexity and a nontrivial amount of build complexity.


Changes in version 0.2.3.25 - 2012-11-19
  The Tor 0.2.3 release series is dedicated to the memory of Len "rabbi"
  Sassaman (1980-2011), a long-time cypherpunk, anonymity researcher,
  Mixmaster maintainer, Pynchon Gate co-designer, CodeCon organizer,
  programmer, and friend. Unstinting in his dedication to the cause of
  freedom, he inspired and helped many of us as we began our work on
  anonymity, and inspires us still. Please honor his memory by writing
  software to protect people's freedoms, and by helping others to do so.

  Tor 0.2.3.25, the first stable release in the 0.2.3 branch, features
  significantly reduced directory overhead (via microdescriptors),
  enormous crypto performance improvements for fast relays on new
  enough hardware, a new v3 TLS handshake protocol that can better
  resist fingerprinting, support for protocol obfuscation plugins (aka
  pluggable transports), better scalability for hidden services, IPv6
  support for bridges, performance improvements like allowing clients
  to skip the first round-trip on the circuit ("optimistic data") and
  refilling token buckets more often, a new "stream isolation" design
  to isolate different applications on different circuits, and many
  stability, security, and privacy fixes.

  Major features (v3 directory protocol):
    - Clients now use microdescriptors instead of regular descriptors
      to build circuits. Microdescriptors are authority-generated
      summaries of regular descriptors' contents, designed to change very
      rarely (see proposal 158 for details). This feature is designed
      to save bandwidth, especially for clients on slow internet
      connections. Use "UseMicrodescriptors 0" to disable it.
    - Caches now download, cache, and serve microdescriptors, as well
      as multiple "flavors" of the consensus, including a flavor that
      describes microdescriptors.

  o Major features (build hardening):
    - Enable gcc and ld hardening by default. Resolves ticket 5210.

  o Major features (relay scaling):
    - When built to use OpenSSL 1.0.1, and built for an x86 or x86_64
      instruction set, take advantage of OpenSSL's AESNI, bitsliced, or
      vectorized AES implementations as appropriate. These can be much,
      much faster than other AES implementations.
    - When using OpenSSL 1.0.0 or later, use OpenSSL's counter mode
      implementation. It makes AES_CTR about 7% faster than our old one
      (which was about 10% faster than the one OpenSSL used to provide).
      Resolves ticket 4526.
    - Use OpenSSL's EVP interface for AES encryption, so that all AES
      operations can use hardware acceleration (if present). Resolves
      ticket 4442.
    - Unconditionally use OpenSSL's AES implementation instead of our
      old built-in one. OpenSSL's AES has been better for a while, and
      relatively few servers should still be on any version of OpenSSL
      that doesn't have good optimized assembly AES.

  o Major features (blocking resistance):
    - Update TLS cipher list to match Firefox 8 and later. Resolves
      ticket 4744.
    - Remove support for clients falsely claiming to support standard
      ciphersuites that they can actually provide. As of modern OpenSSL
      versions, it's not necessary to fake any standard ciphersuite,
      and doing so prevents us from using better ciphersuites in the
      future, since servers can't know whether an advertised ciphersuite
      is really supported or not. Some hosts -- notably, ones with very
      old versions of OpenSSL or where OpenSSL has been built with ECC
      disabled -- will stand out because of this change; TBB users should
      not be affected. Implements the client side of proposal 198.
    - Implement a new handshake protocol (v3) for authenticating Tors to
      each other over TLS. It should be more resistant to fingerprinting
      than previous protocols, and should require less TLS hacking for
      future Tor implementations. Implements proposal 176.
    - Allow variable-length padding cells, to disguise the length of
      Tor's TLS records. Implements part of proposal 184.
    - While we're trying to bootstrap, record how many TLS connections
      fail in each state, and report which states saw the most failures
      in response to any bootstrap failures. This feature may speed up
      diagnosis of censorship events. Implements ticket 3116.

  o Major features (pluggable transports):
    - Clients and bridges can now be configured to use a separate
      "transport" proxy. This approach makes the censorship arms race
      easier by allowing bridges to use protocol obfuscation plugins.
      Implements proposal 180 (tickets 2841 and 3472).

  o Major features (DoS resistance):
    - Now that Tor 0.2.0.x is completely deprecated, enable the final
      part of "Proposal 110: Avoiding infinite length circuits" by
      refusing all circuit-extend requests that do not use a relay_early
      cell. This change helps Tor resist a class of denial-of-service
      attacks by limiting the maximum circuit length.
    - Tear down the circuit if we get an unexpected SENDME cell. Clients
      could use this trick to make their circuits receive cells faster
      than our flow control would have allowed, or to gum up the network,
      or possibly to do targeted memory denial-of-service attacks on
      entry nodes. Fixes bug 6252. Bugfix on the 54th commit on Tor --
      from July 2002, before the release of Tor 0.0.0.

  o Major features (hidden services):
    - Adjust the number of introduction points that a hidden service
      will try to maintain based on how long its introduction points
      remain in use and how many introductions they handle. Fixes
      part of bug 3825.
    - Add a "tor2web mode" for clients that want to connect to hidden
      services non-anonymously (and possibly more quickly). As a safety
      measure to try to keep users from turning this on without knowing
      what they are doing, tor2web mode must be explicitly enabled at
      compile time, and a copy of Tor compiled to run in tor2web mode
      cannot be used as a normal Tor client. Implements feature 2553.

  o Major features (IPv6):
    - Clients can now connect to private bridges over IPv6. Bridges
      still need at least one IPv4 address in order to connect to
      other relays. Note that we don't yet handle the case where the
      user has two bridge lines for the same bridge (one IPv4, one
      IPv6). Implements parts of proposal 186.

  o Major features (directory authorities):
    - Use a more secure consensus parameter voting algorithm. Now at
      least three directory authorities or a majority of them must
      vote on a given parameter before it will be included in the
      consensus. Implements proposal 178.
    - Remove the artificially low cutoff of 20KB to guarantee the Fast
      flag. In the past few years the average relay speed has picked
      up, and while the "top 7/8 of the network get the Fast flag" and
      "all relays with 20KB or more of capacity get the Fast flag" rules
      used to have the same result, now the top 7/8 of the network has
      a capacity more like 32KB. Bugfix on 0.2.1.14-rc. Fixes bug 4489.

  o Major features (performance):
    - Exit nodes now accept and queue data on not-yet-connected streams.
      Previously, the client wasn't allowed to send data until the
      stream was connected, which slowed down all connections. This
      change will enable clients to perform a "fast-start" on streams
      and send data without having to wait for a confirmation that the
      stream has opened. Patch from Ian Goldberg; implements the server
      side of Proposal 174.
    - When using an exit relay running 0.2.3.x, clients can now
      "optimistically" send data before the exit relay reports that
      the stream has opened. This saves a round trip when starting
      connections where the client speaks first (such as web browsing).
      This behavior is controlled by a consensus parameter (currently
      disabled). To turn it on or off manually, use the "OptimisticData"
      torrc option. Implements proposal 181; code by Ian Goldberg.
    - Add a new TokenBucketRefillInterval option to refill token buckets
      more frequently than once per second. This should improve network
      performance, alleviate queueing problems, and make traffic less
      bursty. Implements proposal 183; closes ticket 3630. Design by
      Florian Tschorsch and Björn Scheuermann; implementation by
      Florian Tschorsch.
    - Raise the threshold of server descriptors needed (75%) and exit
      server descriptors needed (50%) before we will declare ourselves
      bootstrapped. This will make clients start building circuits a
      little later, but makes the initially constructed circuits less
      skewed and less in conflict with further directory fetches. Fixes
      ticket 3196.

  o Major features (relays):
    - Relays now try regenerating and uploading their descriptor more
      frequently if they are not listed in the consensus, or if the
      version of their descriptor listed in the consensus is too
      old. This fix should prevent situations where a server declines
      to re-publish itself because it has done so too recently, even
      though the authorities decided not to list its recent-enough
      descriptor. Fix for bug 3327.

  o Major features (stream isolation):
    - You can now configure Tor so that streams from different
      applications are isolated on different circuits, to prevent an
      attacker who sees your streams as they leave an exit node from
      linking your sessions to one another. To do this, choose some way
      to distinguish the applications: have them connect to different
      SocksPorts, or have one of them use SOCKS4 while the other uses
      SOCKS5, or have them pass different authentication strings to the
      SOCKS proxy. Then, use the new SocksPort syntax to configure the
      degree of isolation you need. This implements Proposal 171.
    - There's a new syntax for specifying multiple client ports (such as
      SOCKSPort, TransPort, DNSPort, NATDPort): you can now just declare
      multiple *Port entries with full addr:port syntax on each.
      The old *ListenAddress format is still supported, but you can't
      mix it with the new *Port syntax.

  o Major features (bufferevents):
    - Tor can now optionally build with the "bufferevents" buffered IO
      backend provided by Libevent 2. To use this feature, make sure you
      have the latest possible version of Libevent, and pass the
      --enable-bufferevents flag to configure when building Tor from
      source. This feature will make our networking code more flexible,
      let us stack layers on each other, and let us use more efficient
      zero-copy transports where available.
    - Add experimental support for running on Windows with IOCP and no
      kernel-space socket buffers. This feature is controlled by a new
      "UserspaceIOCPBuffers" config option (off by default), which has
      no effect unless Tor has been built with bufferevents enabled,
      you're running on Windows, and you've set "DisableIOCP 0". In the
      long run, this may help solve or mitigate bug 98.

  o Major features (path selection):
    - The EntryNodes option can now include country codes like {de} or IP
      addresses or network masks. Previously we had disallowed these
      options because we didn't have an efficient way to keep the list up
      to date. Addresses ticket 1982, but see bug 2798 for an unresolved
      issue here.

  o Major features (port forwarding):
    - Add support for automatic port mapping on the many home routers
      that support NAT-PMP or UPnP. To build the support code, you'll
      need to have the libnatpnp library and/or the libminiupnpc library,
      and you'll need to enable the feature specifically by passing
      "--enable-upnp" and/or "--enable-natpnp" to ./configure. To turn
      it on, use the new PortForwarding option.

  o Major features (logging):
    - Add a new 'Heartbeat' log message type to periodically log a message
      describing Tor's status at level Notice. This feature is meant for
      operators who log at notice, and want to make sure that their Tor
      server is still working. Implementation by George Kadianakis.
    - Make logging resolution configurable with a new LogTimeGranularity
      option, and change the default from 1 millisecond to 1 second.
      Implements enhancement 1668.

  o Major features (other):
    - New "DisableNetwork" config option to prevent Tor from launching any
      connections or accepting any connections except on a control port.
      Bundles and controllers can set this option before letting Tor talk
      to the rest of the network, for example to prevent any connections
      to a non-bridge address. Packages like Orbot can also use this
      option to instruct Tor to save power when the network is off.
    - Try to use system facilities for enumerating local interface
      addresses, before falling back to our old approach (which was
      binding a UDP socket, and calling getsockname() on it). That
      approach was scaring OS X users whose draconian firewall
      software warned about binding to UDP sockets regardless of
      whether packets were sent. Now we try to use getifaddrs(),
      SIOCGIFCONF, or GetAdaptersAddresses(), depending on what the
      system supports. Resolves ticket 1827.
    - Add experimental support for a "defaults" torrc file to be parsed
      before the regular torrc. Torrc options override the defaults file's
      options in the same way that the command line overrides the torrc.
      The SAVECONF controller command saves only those options which
      differ between the current configuration and the defaults file. HUP
      reloads both files. Implements task 4552.

  o New directory authorities:
    - Add Faravahar (run by Sina Rabbani) as the ninth v3 directory
      authority. Closes ticket 5749.

  o Security/privacy fixes:
    - Avoid read-from-freed-memory and double-free bugs that could occur
      when a DNS request fails while launching it. Fixes bug 6480;
      bugfix on 0.2.0.1-alpha.
    - Reject any attempt to extend to an internal address. Without
      this fix, a router could be used to probe addresses on an internal
      network to see whether they were accepting connections. Fixes bug
      6710; bugfix on 0.0.8pre1.
    - Close any connection that sends unrecognized junk before the TLS
      handshake. Solves an issue noted in bug 4369.
    - The advertised platform of a relay now includes only its operating
      system's name (e.g., "Linux", "Darwin", "Windows 7"), and not
      its service pack level (for Windows) or its CPU architecture
      (for Unix). Also drop the "git-XYZ" tag in the version. Packagers
      can insert an extra string in the platform line by setting the
      preprocessor variable TOR_BUILD_TAG. Resolves bug 2988.
    - Disable TLS session tickets. OpenSSL's implementation was giving
      our TLS session keys the lifetime of our TLS context objects, when
      perfect forward secrecy would want us to discard anything that
      could decrypt a link connection as soon as the link connection
      was closed. Fixes bug 7139; bugfix on all versions of Tor linked
      against OpenSSL 1.0.0 or later. Found by Florent Daignière.
    - Tor tries to wipe potentially sensitive data after using it, so
      that if some subsequent security failure exposes Tor's memory,
      the damage will be limited. But we had a bug where the compiler
      was eliminating these wipe operations when it decided that the
      memory was no longer visible to a (correctly running) program,
      hence defeating our attempt at defense in depth. We fix that
      by using OpenSSL's OPENSSL_cleanse() operation, which a compiler
      is unlikely to optimize away. Future versions of Tor may use
      a less ridiculously heavy approach for this. Fixes bug 7352.
      Reported in an article by Andrey Karpov.

  o Major bugfixes (crashes and asserts):
    - Avoid a pair of double-free and use-after-mark bugs that can
      occur with certain timings in canceled and re-received DNS
      requests. Fixes bug 6472; bugfix on 0.0.7rc1.
    - Fix a denial of service attack by which any directory authority
      could crash all the others, or by which a single v2 directory
      authority could crash everybody downloading v2 directory
      information. Fixes bug 7191; bugfix on 0.2.0.10-alpha.
    - Fix an assert that directory authorities could trigger on sighup
      during some configuration state transitions. We now don't treat
      it as a fatal error when the new descriptor we just generated in
      init_keys() isn't accepted. Fixes bug 4438; bugfix on 0.2.1.9-alpha.
    - Avoid segfault when starting up having run with an extremely old
      version of Tor and parsing its state file. Fixes bug 6801; bugfix
      on 0.2.2.23-alpha.

  o Major bugfixes (clients):
    - If we are unable to find any exit that supports our predicted ports,
      stop calling them predicted, so that we don't loop and build
      hopeless circuits indefinitely. Fixes bug 3296; bugfix on 0.0.9pre6,
      which introduced predicted ports.
    - Check at each new consensus whether our entry guards were picked
      long enough ago that we should rotate them. Previously, we only
      did this check at startup, which could lead to us holding a guard
      indefinitely. Fixes bug 5380; bugfix on 0.2.1.14-rc.
    - When fetching a bridge descriptor from a bridge authority,
      always do so anonymously, whether we have been able to open
      circuits or not. Partial fix for bug 1938; bugfix on 0.2.0.7-alpha.
      This behavior makes it *safer* to use UpdateBridgesFromAuthority,
      but we'll need to wait for bug 6010 before it's actually usable.

  o Major bugfixes (directory voting):
    - Check more thoroughly to prevent a rogue authority from
      double-voting on any consensus directory parameter. Previously,
      authorities would crash in this case if the total number of
      votes for any parameter exceeded the number of active voters,
      but would let it pass otherwise. Partially fixes bug 5786; bugfix
      on 0.2.2.2-alpha.
    - When computing weight parameters, behave more robustly in the
      presence of a bad bwweightscale value. Previously, the authorities
      would crash if they agreed on a sufficiently broken weight_scale
      value; now, they use a reasonable default and carry on. Fixes the
      rest of bug 5786; bugfix on 0.2.2.17-alpha.
    - If authorities are unable to get a v2 consensus document from other
      directory authorities, they no longer fall back to fetching
      them from regular directory caches. Fixes bug 5635; bugfix on
      0.2.2.26-beta, where routers stopped downloading v2 consensus
      documents entirely.

  o Major bugfixes (relays):
    - Fix a bug handling SENDME cells on nonexistent streams that could
      result in bizarre window values. Report and patch contributed
      pseudonymously. Fixes part of bug 6271. This bug was introduced
      before the first Tor release, in svn commit r152.
    - Don't update the AccountingSoftLimitHitAt state file entry whenever
      tor gets started. This prevents a wrong average bandwidth
      estimate, which would cause relays to always start a new accounting
      interval at the earliest possible moment. Fixes bug 2003; bugfix
      on 0.2.2.7-alpha. Reported by Bryon Eldridge, who also helped
      immensely in tracking this bug down.
    - Fix a possible crash bug when checking for deactivated circuits
      in connection_or_flush_from_first_active_circuit(). Fixes bug 6341;
      bugfix on 0.2.2.7-alpha. Bug report and fix received pseudonymously.
    - Set the SO_REUSEADDR socket option before we call bind() on outgoing
      connections. This change should allow busy exit relays to stop
      running out of available sockets as quickly. Fixes bug 4950;
      bugfix on 0.2.2.26-beta.

  o Major bugfixes (blocking resistance):
    - Bridges no longer include their address in NETINFO cells on outgoing
      OR connections, to allow them to blend in better with clients.
      Removes another avenue for enumerating bridges. Reported by
      "troll_un". Fixes bug 4348; bugfix on 0.2.0.10-alpha, when NETINFO
      cells were introduced.
    - Warn the user when HTTPProxy, but no other proxy type, is
      configured. This can cause surprising behavior: it doesn't send
      all of Tor's traffic over the HTTPProxy -- it sends unencrypted
      directory traffic only. Resolves ticket 4663.

  o Major bugfixes (hidden services):
    - Improve hidden service robustness: when an attempt to connect to
      a hidden service ends, be willing to refetch its hidden service
      descriptors from each of the HSDir relays responsible for them
      immediately. Previously, we would not consider refetching the
      service's descriptors from each HSDir for 15 minutes after the last
      fetch, which was inconvenient if the hidden service was not running
      during the first attempt. Bugfix on 0.2.0.18-alpha; fixes bug 3335.
    - Hidden services now ignore the timestamps on INTRODUCE2 cells.
      They used to check that the timestamp was within 30 minutes
      of their system clock, so they could cap the size of their
      replay-detection cache, but that approach unnecessarily refused
      service to clients with wrong clocks. Bugfix on 0.2.1.6-alpha, when
      the v3 intro-point protocol (the first one which sent a timestamp
      field in the INTRODUCE2 cell) was introduced; fixes bug 3460.
    - When one of a hidden service's introduction points appears to be
      unreachable, stop trying it. Previously, we would keep trying
      to build circuits to the introduction point until we lost the
      descriptor, usually because the user gave up and restarted Tor.
      Fixes part of bug 3825.

  o Changes to default torrc file:
    - Stop listing "socksport 9050" in torrc.sample. We open a socks
      port on 9050 by default anyway, so this should not change anything
      in practice.
    - Stop mentioning the deprecated *ListenAddress options in
      torrc.sample. Fixes bug 5438.
    - Document unit of bandwidth-related options in sample torrc.
      Fixes bug 5621.
    - Fix broken URLs in the sample torrc file, and tell readers about
      the OutboundBindAddress, ExitPolicyRejectPrivate, and
      PublishServerDescriptor options. Addresses bug 4652.

  o Minor features (directory authorities):
    - Consider new, removed or changed IPv6 OR ports a non-cosmetic
      change when the authority is deciding whether to accept a newly
      uploaded descriptor. Implements ticket 6423.
    - Directory authorities are now a little more lenient at accepting
      older router descriptors, or newer router descriptors that don't
      make big changes. This should help ameliorate past and future
      issues where routers think they have uploaded valid descriptors,
      but the authorities don't think so. Fix for ticket 2479.
    - Authority operators can now vote for all relays in a given
      set of countries to be BadDir/BadExit/Invalid/Rejected.
    - Provide two consensus parameters (FastFlagMinThreshold and
      FastFlagMaxThreshold) to control the range of allowable bandwidths
      for the Fast directory flag. These allow authorities to run
      experiments on appropriate requirements for being a "Fast" node.
      The AuthDirFastGuarantee config value still applies. Implements
      ticket 3946.

  o Minor features (bridges / bridge authorities):
    - Make bridge SSL certificates a bit more stealthy by using random
      serial numbers, in the same fashion as OpenSSL when generating
      self-signed certificates. Implements ticket 4584.
    - Tag a bridge's descriptor as "never to be sent unencrypted".
      This shouldn't matter, since bridges don't open non-anonymous
      connections to the bridge authority and don't allow unencrypted
      directory connections from clients, but we might as well make
      sure. Closes bug 5139.
    - The Bridge Authority now writes statistics on how many bridge
      descriptors it gave out in total, and how many unique descriptors
      it gave out. It also lists how often the most and least commonly
      fetched descriptors were given out, as well as the median and
      25th/75th percentile. Implements tickets 4200 and 4294.

  o Minor features (IPv6):
    - Make the code that clients use to detect an address change be
      IPv6-aware, so that it won't fill clients' logs with error
      messages when trying to get the IPv4 address of an IPv6
      connection. Implements ticket 5537.
    - Relays now understand an IPv6 address when they get one from a
      directory server. Resolves ticket 4875.

  o Minor features (hidden services):
    - Expire old or over-used hidden service introduction points.
      Required by fix for bug 3460.
    - Reduce the lifetime of elements of hidden services' Diffie-Hellman
      public key replay-detection cache from 60 minutes to 5 minutes. This
      replay-detection cache is now used only to detect multiple
      INTRODUCE2 cells specifying the same rendezvous point, so we can
      avoid launching multiple simultaneous attempts to connect to it.
    - When a hidden service's introduction point times out, consider
      trying it again during the next attempt to connect to the
      HS. Previously, we would not try it again unless a newly fetched
      descriptor contained it. Required by fixes for bugs 1297 and 3825.

  o Minor features (relays):
    - Relays now include a reason for regenerating their descriptors
      in an HTTP header when uploading to the authorities. This will
      make it easier to debug descriptor-upload issues in the future.
    - Turn on directory request statistics by default and include them in
      extra-info descriptors. Don't break if we have no GeoIP database.
    - Replace files in stats/ rather than appending to them. Now that we
      include statistics in extra-info descriptors, it makes no sense to
      keep old statistics forever. Implements ticket 2930.
    - Relays that set "ConnDirectionStatistics 1" write statistics on the
      bidirectional use of connections to disk every 24 hours.
    - Add a GeoIP file digest to the extra-info descriptor. Implements
      ticket 1883.

  o Minor features (new config options):
    - New config option "DynamicDHGroups" (disabled by default) provides
      each bridge with a unique prime DH modulus to be used during
      SSL handshakes. This option attempts to help against censors
      who might use the Apache DH modulus as a static identifier for
      bridges. Addresses ticket 4548.
    - New config option "DisableDebuggerAttachment" (on by default)
      to prevent basic debugging attachment attempts by other processes.
      Supports Mac OS X and Gnu/Linux. Resolves ticket 3313.
    - Ordinarily, Tor does not count traffic from private addresses (like
      127.0.0.1 or 10.0.0.1) when calculating rate limits or accounting.
      There is now a new option, CountPrivateBandwidth, to disable this
      behavior. Patch from Daniel Cagara.

  o Minor features (different behavior for old config options):
    - Allow MapAddress directives to specify matches against super-domains,
      as in "MapAddress *.torproject.org *.torproject.org.torserver.exit".
      Implements issue 933.
    - Don't disable the DirPort when we cannot exceed our AccountingMax
      limit during this interval because the effective bandwidthrate is
      low enough. This is useful in a situation where AccountMax is only
      used as an additional safeguard or to provide statistics.
    - Add port 6523 (Gobby) to LongLivedPorts. Patch by intrigeri;
      implements ticket 3439.
    - When configuring a large set of nodes in EntryNodes, and there are
      enough of them listed as Guard so that we don't need to consider
      the non-guard entries, prefer the ones listed with the Guard flag.
    - If you set the NumCPUs option to 0, Tor will now try to detect how
      many CPUs you have. This is the new default behavior.
    - The NodeFamily option -- which let you declare that you want to
      consider nodes to be part of a family whether they list themselves
      that way or not -- now allows IP address ranges and country codes.

  o Minor features (new command-line config behavior):
    - Slightly change behavior of "list" options (that is, config
      options that can appear more than once) when they appear both in
      torrc and on the command line. Previously, the command-line options
      would be appended to the ones from torrc. Now, the command-line
      options override the torrc options entirely. This new behavior
      allows the user to override list options (like exit policies and
      ports to listen on) from the command line, rather than simply
      appending to the list.
    - You can get the old (appending) command-line behavior for "list"
      options by prefixing the option name with a "+".
    - You can remove all the values for a "list" option from the command
      line without adding any new ones by prefixing the option name
      with a "/".

  o Minor features (controller, new events):
    - Extend the control protocol to report flags that control a circuit's
      path selection in CIRC events and in replies to 'GETINFO
      circuit-status'. Implements part of ticket 2411.
    - Extend the control protocol to report the hidden service address
      and current state of a hidden-service-related circuit in CIRC
      events and in replies to 'GETINFO circuit-status'. Implements part
      of ticket 2411.
    - Include the creation time of a circuit in CIRC and CIRC2
      control-port events and the list produced by the 'GETINFO
      circuit-status' control-port command.
    - Add a new CONF_CHANGED event so that controllers can be notified
      of any configuration changes made by other controllers, or by the
      user. Implements ticket 1692.
    - Add a new SIGNAL event to the controller interface so that
      controllers can be notified when Tor handles a signal. Resolves
      issue 1955. Patch by John Brooks.

  o Minor features (controller, new getinfo options):
    - Expose our view of whether we have gone dormant to the controller,
      via a new "GETINFO dormant" value. Torbutton and other controllers
      can use this to avoid doing periodic requests through Tor while
      it's dormant (bug 4718). Resolves ticket 5954.
    - Add a new GETINFO option to get total bytes read and written. Patch
      from pipe, revised by atagar. Resolves ticket 2345.
    - Implement new GETINFO controller fields to provide information about
      the Tor process's pid, euid, username, and resource limits.

  o Minor features (controller, other):
    - Allow controllers to request an event notification whenever a
      circuit is cannibalized or its purpose is changed. Implements
      part of ticket 3457.
    - Use absolute path names when reporting the torrc filename in the
      control protocol, so a controller can more easily find the torrc
      file. Resolves bug 1101.
    - When reporting the path to the cookie file to the controller,
      give an absolute path. Resolves ticket 4881.

  o Minor features (log messages):
    - Add more information to a log statement that might help track down
      bug 4091. If you're seeing "Bug: tor_addr_is_internal() called with a
      non-IP address" messages (or any Bug messages, for that matter!),
      please let us know about it.
    - If EntryNodes are given, but UseEntryGuards is set to 0, warn that
      EntryNodes will have no effect. Resolves issue 2571.
    - Try to make the introductory warning message that Tor prints on
      startup more useful for actually finding help and information.
      Resolves ticket 2474.
    - When the system call to create a listener socket fails, log the
      error message explaining why. This may help diagnose bug 4027.

  o Minor features (other):
    - When we fail to initialize Libevent, retry with IOCP disabled so we
      don't need to turn on multi-threading support in Libevent, which in
      turn requires a working socketpair(). This is a workaround for bug
      4457, which affects Libevent versions from 2.0.1-alpha through
      2.0.15-stable.
    - When starting as root and then changing our UID via the User
      control option, and we have a ControlSocket configured, make sure
      that the ControlSocket is owned by the same account that Tor will
      run under. Implements ticket 3421; fix by Jérémy Bobbio.
    - Accept attempts to include a password authenticator in the
      handshake, as supported by SOCKS5. This handles SOCKS clients that
      don't know how to omit a password when authenticating. Resolves
      bug 1666.
    - Check for and recover from inconsistency in the microdescriptor
      cache. This will make it harder for us to accidentally free a
      microdescriptor without removing it from the appropriate data
      structures. Fixes issue 3135; issue noted by "wanoskarnet".
    - Shorten links in the tor-exit-notice file. Patch by Christian Kujau.

  o Minor bugfixes (code security):
    - Prevent a null-pointer dereference when receiving a data cell
      for a nonexistent stream when the circuit in question has an
      empty deliver window. We don't believe this is triggerable,
      since we don't currently allow deliver windows to become empty,
      but the logic is tricky enough that it's better to make the code
      robust. Fixes bug 5541; bugfix on 0.0.2pre14.
    - Fix a (harmless) integer overflow in cell statistics reported by
      some fast relays. Fixes bug 5849; bugfix on 0.2.2.1-alpha.
    - Fix our implementation of crypto_random_hostname() so it can't
      overflow on ridiculously large inputs. (No Tor version has ever
      provided this kind of bad inputs, but let's be correct in depth.)
      Fixes bug 4413; bugfix on 0.2.2.9-alpha. Fix by Stephen Palmateer.
    - Add a (probably redundant) memory clear between iterations of
      the router status voting loop, to prevent future coding errors
      where data might leak between iterations of the loop. Resolves
      ticket 6514.

  o Minor bugfixes (wrapper functions):
    - Abort if tor_vasprintf() fails in connection_printf_to_buf() (a
      utility function used in the control-port code). This shouldn't
      ever happen unless Tor is completely out of memory, but if it did
      happen and Tor somehow recovered from it, Tor could have sent a log
      message to a control port in the middle of a reply to a controller
      command. Fixes part of bug 3428; bugfix on 0.1.2.3-alpha.
    - Fix some (not actually triggerable) buffer size checks in usage of
      tor_inet_ntop(). Fixes bug 4434; bugfix on Tor 0.2.0.1-alpha. Patch
      by Anders Sundman.
    - Fix parsing of some corner-cases with tor_inet_pton(). Fixes
      bug 4515; bugfix on 0.2.0.1-alpha; fix by Anders Sundman.
    - Enforce correct return behavior of tor_vsscanf() when the '%%'
      pattern is used. Fixes bug 5558. Bugfix on 0.2.1.13.
    - Make our replacement implementation of strtok_r() compatible with
      the standard behavior of strtok_r(). Patch by nils. Fixes bug 5091;
      bugfix on 0.2.2.1-alpha.
    - Find more places in the code that should have been testing for
      invalid sockets using the SOCKET_OK macro. Required for a fix
      for bug 4533. Bugfix on 0.2.2.28-beta.

  o Minor bugfixes (code correctness):
    - Check return value of fputs() when writing authority certificate
      file. Fixes Coverity issue 709056; bugfix on 0.2.0.1-alpha.
    - When building Tor on Windows with -DUNICODE (not default), ensure
      that error messages, filenames, and DNS server names are always
      NUL-terminated when we convert them to a single-byte encoding.
      Fixes bug 5909; bugfix on 0.2.2.16-alpha.
    - Fix a memory leak when trying to launch a DNS request when the
      nameservers are unconfigurable. Fixes bug 5916; bugfix on Tor
      0.1.2.1-alpha.
    - Correct file sizes when reading binary files on Cygwin, to avoid
      a bug where Tor would fail to read its state file. Fixes bug 6844;
      bugfix on 0.1.2.7-alpha.
    - Make sure to set *socket_error in all error cases in
      connection_connect(), so it can't produce a warning about
      errno being zero from errno_to_orconn_end_reason(). Bugfix on
      0.2.1.1-alpha; resolves ticket 6028.
    - Initialize conn->addr to a valid state in spawn_cpuworker(). Fixes
      bug 4532; found by "troll_un".

  o Minor bugfixes (clients):
    - Allow one-hop directory-fetching circuits the full "circuit build
      timeout" period, rather than just half of it, before failing them
      and marking the relay down. This fix should help reduce cases where
      clients declare relays (or worse, bridges) unreachable because
      the TLS handshake takes a few seconds to complete. Fixes bug 6743;
      bugfix on 0.2.2.2-alpha, where we changed the timeout from a static
      30 seconds.
    - Ensure we don't cannibalize circuits that are longer than three hops
      already, so we don't end up making circuits with 5 or more
      hops. Patch contributed by wanoskarnet. Fixes bug 5231; bugfix on
      0.1.0.1-rc which introduced cannibalization.

  o Minor bugfixes (relays):
    - Don't publish a new relay descriptor when we reload our onion key,
      unless the onion key has actually changed. Fixes bug 3263 and
      resolves another cause of bug 1810. Bugfix on 0.1.1.11-alpha.
    - When relays refuse a "create" cell because their queue of pending
      create cells is too big (typically because their cpu can't keep up
      with the arrival rate), send back reason "resource limit" rather
      than reason "internal", so network measurement scripts can get a
      more accurate picture. Bugfix on 0.1.1.11-alpha; fixes bug 7037.
    - Exit nodes don't need to fetch certificates for authorities that
      they don't recognize; only directory authorities, bridges,
      and caches need to do that. Fixes part of bug 2297; bugfix on
      0.2.2.11-alpha.

  o Minor bugfixes (directory authority / mirrors):
    - Avoid O(n^2) performance characteristics when parsing a large
      extrainfo cache. Fixes bug 5828; bugfix on 0.2.0.1-alpha.
    - Authorities no longer include any router in their microdescriptor
      consensuses for which they couldn't generate or agree on a
      microdescriptor. Fixes the second piece of bug 6404; fix on
      0.2.2.6-alpha.
    - When checking for requested signatures on the latest consensus
      before serving it to a client, make sure to check the right
      consensus flavor. Bugfix on 0.2.2.6-alpha.
    - Fix an edge case where TestingTorNetwork is set but the authorities
      and relays all have an uptime of zero, so the private Tor network
      could briefly lack support for hidden services. Fixes bug 3886;
      bugfix on 0.2.2.18-alpha.
    - Directory caches no longer refuse to clean out descriptors because
      of missing v2 networkstatus documents, unless they're configured
      to retrieve v2 networkstatus documents. Fixes bug 4838; bugfix on
      0.2.2.26-beta. Patch by Daniel Bryg.
    - Don't serve or accept v2 hidden service descriptors over a relay's
      DirPort. It's never correct to do so, and disabling it might
      make it more annoying to exploit any bugs that turn up in the
      descriptor-parsing code. Fixes bug 7149.

  o Minor bugfixes (hidden services, client-side):
    - Assert that hidden-service-related operations are not performed
      using single-hop circuits. Previously, Tor would assert that
      client-side streams are not attached to single-hop circuits,
      but not that other sensitive operations on the client and service
      side are not performed using single-hop circuits. Fixes bug 3332;
      bugfix on 0.0.6.
    - Avoid undefined behavior when parsing the list of supported
      rendezvous/introduction protocols in a hidden service descriptor.
      Previously, Tor would have confused (as-yet-unused) protocol version
      numbers greater than 32 with lower ones on many platforms. Fixes
      bug 6827; bugfix on 0.2.0.10-alpha. Found by George Kadianakis.
    - Don't close hidden service client circuits which have almost
      finished connecting to their destination when they reach
      the normal circuit-build timeout. Previously, we would close
      introduction circuits which are waiting for an acknowledgement
      from the introduction point, and rendezvous circuits which have
      been specified in an INTRODUCE1 cell sent to a hidden service,
      after the normal CBT. Now, we mark them as 'timed out', and launch
      another rendezvous attempt in parallel. This behavior change can
      be disabled using the new CloseHSClientCircuitsImmediatelyOnTimeout
      option. Fixes part of bug 1297; bugfix on 0.2.2.2-alpha.

  o Minor bugfixes (hidden services, service-side):
    - Don't close hidden-service-side rendezvous circuits when they
      reach the normal circuit-build timeout. This behavior change can
      be disabled using the new
      CloseHSServiceRendCircuitsImmediatelyOnTimeout option. Fixes the
      remaining part of bug 1297; bugfix on 0.2.2.2-alpha.
    - Don't launch more than 10 service-side introduction-point circuits
      for a hidden service in five minutes. Previously, we would consider
      launching more introduction-point circuits if at least one second
      had passed without any introduction-point circuits failing. Fixes
      bug 4607; bugfix on 0.0.7pre1.

  o Minor bugfixes (config option behavior):
    - If the user tries to set MyFamily on a bridge, refuse to
      do so, and warn about the security implications. Fixes bug 4657;
      bugfix on 0.2.0.3-alpha.
    - The "--quiet" and "--hush" options now apply not only to Tor's
      behavior before logs are configured, but also to Tor's behavior in
      the absense of configured logs. Fixes bug 3550; bugfix on
      0.2.0.10-alpha.
    - Change the AllowDotExit rules so they should actually work.
      We now enforce AllowDotExit only immediately after receiving an
      address via SOCKS or DNSPort: other sources are free to provide
      .exit addresses after the resolution occurs. Fixes bug 3940;
      bugfix on 0.2.2.1-alpha.
    - Make "LearnCircuitBuildTimeout 0" work more reliably. Specifically,
      don't depend on the consensus parameters or compute adaptive
      timeouts when it is disabled. Fixes bug 5049; bugfix on
      0.2.2.14-alpha.
    - After we pick a directory mirror, we would refuse to use it if
      it's in our ExcludeExitNodes list, resulting in mysterious failures
      to bootstrap for people who just wanted to avoid exiting from
      certain locations. Fixes bug 5623; bugfix on 0.2.2.25-alpha.
    - When told to add a bridge with the same digest as a preexisting
      bridge but a different addr:port, change the addr:port as
      requested. Previously we would not notice the change. Fixes half
      of bug 5603; fix on 0.2.2.26-beta.

  o Minor bugfixes (controller):
    - Allow manual 'authenticate' commands to the controller interface
      from netcat (nc) as well as telnet. We were rejecting them because
      they didn't come with the expected whitespace at the end of the
      command. Bugfix on 0.1.1.1-alpha; fixes bug 2893.
    - Report a real bootstrap problem to the controller on router
      identity mismatch. Previously we just said "foo", which probably
      made a lot of sense at the time. Fixes bug 4169; bugfix on
      0.2.1.1-alpha.
    - When we receive a SIGHUP and the controller __ReloadTorrcOnSIGHUP
      option is set to 0 (which Vidalia version 0.2.16 now does when
      a SAVECONF attempt fails), perform other actions that SIGHUP
      usually causes (like reopening the logs). Fixes bug 5095; bugfix
      on 0.2.1.9-alpha.
    - Correctly handle checking the permissions on the parent
      directory of a control socket in the root directory. Bug found
      by Esteban Manchado Velázquez. Fixes bug 5089; bugfix on Tor
      0.2.2.26-beta.
    - End AUTHCHALLENGE error messages (in the control protocol) with
      a CRLF. Fixes bug 5760; bugfix on 0.2.2.36.

  o Minor bugfixes (network reading/writing):
    - Disable writing on marked-for-close connections when they are
      blocked on bandwidth, to prevent busy-looping in Libevent. Fixes
      bug 5263; bugfix on 0.0.2pre13, where we first added a special
      case for flushing marked connections.
    - Make sure that there are no unhandled pending TLS errors before
      reading from a TLS stream. We had checks in 0.1.0.3-rc, but
      lost them in 0.1.0.5-rc when we refactored read_to_buf_tls().
      Bugfix on 0.1.0.5-rc; fixes bug 4528.
    - Detect SSL handshake even when the initial attempt to write the
      server hello fails. Fixes bug 4592; bugfix on 0.2.0.13-alpha.
    - If the client fails to set a reasonable set of ciphersuites
      during its v2 handshake renegotiation, allow the renegotiation to
      continue nevertheless (i.e. send all the required certificates).
      Fixes bug 4591; bugfix on 0.2.0.20-rc.

  o Minor bugfixes (other):
    - Exit nodes now correctly report EADDRINUSE and EADDRNOTAVAIL as
      resource exhaustion, so that clients can adjust their load to
      try other exits. Fixes bug 4710; bugfix on 0.1.0.1-rc, which
      started using END_STREAM_REASON_RESOURCELIMIT.
    - Don't check for whether the address we're using for outbound
      connections has changed until after the outbound connection has
      completed. On Windows, getsockname() doesn't succeed until the
      connection is finished. Fixes bug 5374; bugfix on 0.1.1.14-alpha.
    - Don't hold a Windows file handle open for every file mapping;
      the file mapping handle is sufficient. Fixes bug 5951; bugfix on
      0.1.2.1-alpha.
    - Fix wrong TCP port range in parse_port_range(). Fixes bug 6218;
      bugfix on 0.2.1.10-alpha.
    - If we fail to write a microdescriptor to the disk cache, do not
      continue replacing the old microdescriptor file. Fixes bug 2954;
      bugfix on 0.2.2.6-alpha.

  o Minor bugfixes (log messages, path selection):
    - Downgrade "set buildtimeout to low value" messages to "info"
      severity; they were never an actual problem, there was never
      anything reasonable to do about them, and they tended to spam logs
      from time to time. Fixes bug 6251; bugfix on 0.2.2.2-alpha.
    - Rate-limit the "Weighted bandwidth is 0.000000" message, and add
      more information to it, so that we can track it down in case it
      returns again. Mitigates bug 5235.
    - Check CircuitBuildTimeout and LearnCircuitBuildTimeout in
      options_validate(); warn if LearnCircuitBuildTimeout is disabled and
      CircuitBuildTimeout is set unreasonably low. Resolves ticket 5452.
    - Issue a log message if a guard completes less than 40% of your
      circuits. Threshold is configurable by torrc option
      PathBiasNoticeRate and consensus parameter pb_noticepct. There is
      additional, off-by-default code to disable guards which fail too
      many circuits. Addresses ticket 5458.

  o Minor bugfixes (log messages, client):
    - Downgrade "Got a certificate, but we already have it" log messages
      from warning to info, except when we're a dirauth. Fixes bug 5238;
      bugfix on 0.2.1.7-alpha.
    - Fix the log message describing how we work around discovering
      that our version is the ill-fated OpenSSL 0.9.8l. Fixes bug
      4837; bugfix on 0.2.2.9-alpha.
    - When logging about a disallowed .exit name, do not also call it
      an "invalid onion address". Fixes bug 3325; bugfix on 0.2.2.9-alpha.
    - Fix a log message suggesting that people contact a non-existent
      email address. Fixes bug 3448.
    - Rephrase the log message emitted if the TestSocks check is
      successful. Patch from Fabian Keil; fixes bug 4094.
    - Log (at debug level) whenever a circuit's purpose is changed.
    - Log SSL state transitions at log level DEBUG, log domain
      HANDSHAKE. This can be useful for debugging censorship events.
      Implements ticket 3264.
    - We now log which torrc file we're using on startup. Implements
      ticket 2444.
    - Rate-limit log messages when asked to connect anonymously to
      a private address. When these hit, they tended to hit fast and
      often. Also, don't bother trying to connect to addresses that we
      are sure will resolve to 127.0.0.1: getting 127.0.0.1 in a directory
      reply makes us think we have been lied to, even when the address the
      client tried to connect to was "localhost." Resolves ticket 2822.

  o Minor bugfixes (log messages, non-client):
    - Downgrade "eventdns rejected address" message to LOG_PROTOCOL_WARN.
      Fixes bug 5932; bugfix on 0.2.2.7-alpha.
    - Don't log that we have "decided to publish new relay descriptor"
      unless we are actually publishing a descriptor. Fixes bug 3942;
      bugfix on 0.2.2.28-beta.
    - Log which authority we're missing votes from when we go to fetch
      them from the other auths.
    - Replace "Sending publish request" log messages with "Launching
      upload", so that they no longer confusingly imply that we're
      sending something to a directory we might not even be connected
      to yet. Fixes bug 3311; bugfix on 0.2.0.10-alpha.
    - Warn when Tor is configured to use accounting in a way that can
      link a hidden service to some other hidden service or public
      address. Resolves ticket 6490.
    - Fix a minor formatting issue in one of tor-gencert's error messages.
      Fixes bug 4574.

  o Testing:
    - Update to the latest version of the tinytest unit testing framework.
      This includes a couple of bugfixes that can be relevant for
      running forked unit tests on Windows, and removes all reserved
      identifiers.
    - Avoid a false positive in the util/threads unit test by increasing
      the maximum timeout time. Fixes bug 6227; bugfix on 0.2.0.4-alpha.
    - Make it possible to set the TestingTorNetwork configuration
      option using AlternateDirAuthority and AlternateBridgeAuthority
      as an alternative to setting DirServer. Addresses ticket 6377.
    - Add a unit test for the environment_variable_names_equal() function.
    - A wide variety of new unit tests by Esteban Manchado Velázquez.
    - Numerous new unit tests for functions in util.c and address.c by
      Anders Sundman.
    - The long-disabled benchmark tests are now split into their own
      ./src/test/bench binary.
    - The benchmark tests can now use more accurate timers than
      gettimeofday() when such timers are available.
    - Use tt_assert(), not tor_assert(), for checking for test failures.
      This makes the unit tests more able to go on in the event that
      one of them fails.

  o Build improvements:
    - Use the dead_strip option when building Tor on OS X. This reduces
      binary size by almost 19% when linking openssl and libevent
      statically, which we do for Tor Browser Bundle.
    - Provide a better error message about possible OSX Asciidoc failure
      reasons. Fixes bug 6436.
    - Detect attempts to build Tor on (as yet hypothetical) versions
      of Windows where sizeof(intptr_t) != sizeof(SOCKET). Partial
      fix for bug 4533. Bugfix on 0.2.2.28-beta.
    - On Windows, we now define the _WIN32_WINNT macros only if they
      are not already defined. This lets the person building Tor decide,
      if they want, to require a later version of Windows.
    - Our autogen.sh script now uses autoreconf to launch autoconf,
      automake, and so on. This is more robust against some of the failure
      modes associated with running the autotools pieces on their own.
    - Running "make version" now displays the version of Tor that
      we're about to build. Idea from katmagic; resolves issue 4400.
    - Make 'tor --digests' list hashes of all Tor source files. Bugfix
      on 0.2.2.4-alpha; fixes bug 3427.
    - New --enable-static-tor configure option for building Tor as
      statically as possible. Idea, general hackery and thoughts from
      Alexei Czeskis, John Gilmore, Jacob Appelbaum. Implements ticket
      2702.
    - Limited, experimental support for building with nmake and MSVC.

  o Build requirements:
    - Building Tor with bufferevent support now requires Libevent
      2.0.13-stable or later. Previous versions of Libevent had bugs in
      SSL-related bufferevents and related issues that would make Tor
      work badly with bufferevents. Requiring 2.0.13-stable also allows
      Tor with bufferevents to take advantage of Libevent APIs
      introduced after 2.0.8-rc.
    - Our build system requires automake 1.6 or later to create the
      Makefile.in files. Previously, you could have used 1.4.
      This only affects developers and people building Tor from git;
      people who build Tor from the source distribution without changing
      the Makefile.am files should be fine.
    - Detect when we try to build on a platform that doesn't define
      AF_UNSPEC to 0. We don't work there, so refuse to compile.

  o Build fixes (compile/link):
    - Format more doubles with %f, not %lf. Patch from grarpamp to make
      Tor build correctly on older BSDs again. Fixes bug 3894; bugfix on
      Tor 0.2.0.8-alpha.
    - When building with --enable-static-tor on OpenBSD, do not
      erroneously attempt to link -lrt. Fixes bug 5103.
    - Set _WIN32_WINNT to 0x0501 consistently throughout the code, so
      that IPv6 stuff will compile on MSVC, and compilation issues
      will be easier to track down. Fixes bug 5861.
    - Fix build and 64-bit compile warnings from --enable-openbsd-malloc.
      Fixes bug 6379. Bugfix on 0.2.0.20-rc.
    - Make Tor build correctly again with -DUNICODE -D_UNICODE defined.
      Fixes bug 6097; bugfix on 0.2.2.16-alpha.

  o Build fixes (other):
    - Use the _WIN32 macro throughout our code to detect Windows.
      (Previously we had used the obsolete 'WIN32' and the idiosyncratic
      'MS_WINDOWS'.)
    - Properly handle the case where the build-tree is not the same
      as the source tree when generating src/common/common_sha1.i,
      src/or/micro-revision.i, and src/or/or_sha1.i. Fixes bug 3953;
      bugfix on 0.2.0.1-alpha.
    - During configure, search for library containing cos function as
      libm lives in libcore on some platforms (BeOS/Haiku). Linking
      against libm was hard-coded before. Fixes the first part of bug
      4727; bugfix on 0.2.2.2-alpha. Patch and analysis by Martin Hebnes
      Pedersen.
    - Prevent a false positive from the check-spaces script, by disabling
      the "whitespace between function name and (" check for functions
      named 'op()'.

  o Packaging (RPM) changes:
    - Update our default RPM spec files to work with mock and rpmbuild
      on RHEL/Fedora. They have an updated set of dependencies and
      conflicts, a fix for an ancient typo when creating the "_tor"
      user, and better instructions. Thanks to Ondrej Mikle for the
      patch series. Fixes bug 6043.
    - On OpenSUSE, create the /var/run/tor directory on startup if it
      is not already created. Patch from Andreas Stieger. Fixes bug 2573.

  o Code refactoring (safety):
    - Do not use SMARTLIST_FOREACH for any loop whose body exceeds
      10 lines. Also, don't nest them. Doing so in the past has
      led to hard-to-debug code. The new style is to use the
      SMARTLIST_FOREACH_{BEGIN,END} pair. Addresses issue 6400.
    - Use macros to indicate OpenSSL versions, so we don't need to worry
      about accidental hexadecimal bit shifts.
    - Use tor_sscanf() in place of scanf() in more places through the
      code. This makes us a little more locale-independent, and
      should help shut up code-analysis tools that can't tell
      a safe sscanf string from a dangerous one.
    - Convert more instances of tor_snprintf+tor_strdup into tor_asprintf.
    - Use the smartlist_add_asprintf() alias more consistently.

  o Code refactoring (consolidate):
    - A major revision to our internal node-selecting and listing logic.
      Tor already had at least two major ways to look at the question of
      "which Tor servers do we know about": a list of router descriptors,
      and a list of entries in the current consensus. With
      microdescriptors, we're adding a third. Having so many systems
      without an abstraction layer over them was hurting the codebase.
      Now, we have a new "node_t" abstraction that presents a consistent
      interface to a client's view of a Tor node, and holds (nearly) all
      of the mutable state formerly in routerinfo_t and routerstatus_t.
    - Move tor_gettimeofday_cached() into compat_libevent.c, and use
      Libevent's notion of cached time when possible.
    - Remove duplicate code for invoking getrlimit() from control.c.
    - Use OpenSSL's built-in SSL_state_string_long() instead of our
      own homebrewed ssl_state_to_string() replacement. Patch from
      Emile Snyder. Fixes bug 4653.
    - Change the symmetric cipher interface so that creating and
      initializing a stream cipher are no longer separate functions.

  o Code refactoring (separate):
    - Make a new "entry connection" struct as an internal subtype of "edge
      connection", to simplify the code and make exit connections smaller.
    - Split connection_about_to_close() into separate functions for each
      connection type.
    - Rewrite the listener-selection logic so that parsing which ports
      we want to listen on is now separate from binding to the ports
      we want.

  o Code refactoring (name changes):
    - Rename a handful of old identifiers, mostly related to crypto
      structures and crypto functions. By convention, our "create an
      object" functions are called "type_new()", our "free an object"
      functions are called "type_free()", and our types indicate that
      they are types only with a final "_t". But a handful of older
      types and functions broke these rules, with function names like
      "type_create" or "subsystem_op_type", or with type names like
      type_env_t.
    - Rename Tor functions that turn strings into addresses, so that
      "parse" indicates that no hostname resolution occurs, and
      "lookup" indicates that hostname resolution may occur. This
      should help prevent mistakes in the future. Fixes bug 3512.
    - Use the name "CERTS" consistently to refer to the new cell type;
      we were calling it CERT in some places and CERTS in others.
    - Use a TOR_INVALID_SOCKET macro when initializing a socket to an
      invalid value, rather than just -1.
    - Rename the bench_{aes,dmap} functions to test_*, so that tinytest
      can pick them up when the tests aren't disabled. Bugfix on
      0.2.2.4-alpha which introduced tinytest.

  o Code refactoring (other):
    - Defensively refactor rend_mid_rendezvous() so that protocol
      violations and length checks happen in the beginning. Fixes
      bug 5645.
    - Remove the pure attribute from all functions that used it
      previously. In many cases we assigned it incorrectly, because the
      functions might assert or call impure functions, and we don't have
      evidence that keeping the pure attribute is worthwhile. Implements
      changes suggested in ticket 4421.
    - Move the replay-detection cache for the RSA-encrypted parts of
      INTRODUCE2 cells to the introduction point data structures.
      Previously, we would use one replay-detection cache per hidden
      service. Required by fix for bug 3460.
    - The helper programs tor-gencert, tor-resolve, and tor-checkkey
      no longer link against Libevent: they never used it, but
      our library structure used to force them to link it.

  o Removed features and files:
    - Remove all internal support for unpadded RSA. We never used it, and
      it would be a bad idea to start.
    - Remove some workaround code for OpenSSL 0.9.6 (which is no longer
      supported).
    - Remove some redundant #include directives throughout the code.
      Patch from Andrea Gelmini.
    - Remove some old code to remember statistics about which descriptors
      we've served as a directory mirror. The feature wasn't used and
      is outdated now that microdescriptors are around.
    - Remove some old code to work around even older versions of Tor that
      used forked processes to handle DNS requests. Such versions of Tor
      are no longer in use as relays.
    - The "torify" script no longer supports the "tsocks" socksifier
      tool, since tsocks doesn't support DNS and UDP right for Tor.
      Everyone should be using torsocks instead. Fixes bugs 3530 and
      5180. Based on a patch by "ugh".
    - Remove the torrc.bridge file: we don't use it for anything, and
      it had become badly desynchronized from torrc.sample. Resolves
      bug 5622.

  o Documentation:
    - Begin a doc/state-contents.txt file to explain the contents of
      the Tor state file. Fixes bug 2987.
    - Clarify the documentation for the Alternate*Authority options.
      Fixes bug 6387.
    - Document the --defaults-torrc option, and the new semantics for
      overriding, extending, and clearing lists of options. Closes
      bug 4748.
    - Add missing man page documentation for consensus and microdesc
      files. Resolves ticket 6732.
    - Fix some typos in the manpages. Patch from A. Costa. Fixes bug 6500.

  o Documentation fixes:
    - Improve the manual's documentation for the NT Service command-line
      options. Addresses ticket 3964.
    - Clarify SessionGroup documentation slightly; resolves ticket 5437.
    - Document the changes to the ORPort and DirPort options, and the
      fact that {OR/Dir}ListenAddress is now unnecessary (and
      therefore deprecated). Resolves ticket 5597.
    - Correct a broken faq link in the INSTALL file. Fixes bug 2307.
    - Clarify that hidden services are TCP only. Fixes bug 6024.


Changes in version 0.2.2.39 - 2012-09-11
  Tor 0.2.2.39 fixes two more opportunities for remotely triggerable
  assertions.

  o Security fixes:
    - Fix an assertion failure in tor_timegm() that could be triggered
      by a badly formatted directory object. Bug found by fuzzing with
      Radamsa. Fixes bug 6811; bugfix on 0.2.0.20-rc.
    - Do not crash when comparing an address with port value 0 to an
      address policy. This bug could have been used to cause a remote
      assertion failure by or against directory authorities, or to
      allow some applications to crash clients. Fixes bug 6690; bugfix
      on 0.2.1.10-alpha.


Changes in version 0.2.2.38 - 2012-08-12
  Tor 0.2.2.38 fixes a remotely triggerable crash bug, and fixes a timing
  attack that could in theory leak path information.

  o Security fixes:
    - Avoid an uninitialized memory read when reading a vote or consensus
      document that has an unrecognized flavor name. This read could
      lead to a remote crash bug. Fixes bug 6530; bugfix on 0.2.2.6-alpha.
    - Try to leak less information about what relays a client is
      choosing to a side-channel attacker. Previously, a Tor client would
      stop iterating through the list of available relays as soon as it
      had chosen one, thus finishing a little earlier when it picked
      a router earlier in the list. If an attacker can recover this
      timing information (nontrivial but not proven to be impossible),
      they could learn some coarse-grained information about which relays
      a client was picking (middle nodes in particular are likelier to
      be affected than exits). The timing attack might be mitigated by
      other factors (see bug 6537 for some discussion), but it's best
      not to take chances. Fixes bug 6537; bugfix on 0.0.8rc1.


Changes in version 0.2.2.37 - 2012-06-06
  Tor 0.2.2.37 introduces a workaround for a critical renegotiation
  bug in OpenSSL 1.0.1 (where 20% of the Tor network can't talk to itself
  currently).

  o Major bugfixes:
    - Work around a bug in OpenSSL that broke renegotiation with TLS
      1.1 and TLS 1.2. Without this workaround, all attempts to speak
      the v2 Tor connection protocol when both sides were using OpenSSL
      1.0.1 would fail. Resolves ticket 6033.
    - When waiting for a client to renegotiate, don't allow it to add
      any bytes to the input buffer. This fixes a potential DoS issue.
      Fixes bugs 5934 and 6007; bugfix on 0.2.0.20-rc.
    - Fix an edge case where if we fetch or publish a hidden service
      descriptor, we might build a 4-hop circuit and then use that circuit
      for exiting afterwards -- even if the new last hop doesn't obey our
      ExitNodes config option. Fixes bug 5283; bugfix on 0.2.0.10-alpha.

  o Minor bugfixes:
    - Fix a build warning with Clang 3.1 related to our use of vasprintf.
      Fixes bug 5969. Bugfix on 0.2.2.11-alpha.

  o Minor features:
    - Tell GCC and Clang to check for any errors in format strings passed
      to the tor_v*(print|scan)f functions.


Changes in version 0.2.2.36 - 2012-05-24
  Tor 0.2.2.36 updates the addresses for two of the eight directory
  authorities, fixes some potential anonymity and security issues,
  and fixes several crash bugs.

  Tor 0.2.1.x has reached its end-of-life. Those Tor versions have many
  known flaws, and nobody should be using them. You should upgrade. If
  you're using a Linux or BSD and its packages are obsolete, stop using
  those packages and upgrade anyway.

  o Directory authority changes:
    - Change IP address for maatuska (v3 directory authority).
    - Change IP address for ides (v3 directory authority), and rename
      it to turtles.

  o Security fixes:
    - When building or running with any version of OpenSSL earlier
      than 0.9.8s or 1.0.0f, disable SSLv3 support. These OpenSSL
      versions have a bug (CVE-2011-4576) in which their block cipher
      padding includes uninitialized data, potentially leaking sensitive
      information to any peer with whom they make a SSLv3 connection. Tor
      does not use SSL v3 by default, but a hostile client or server
      could force an SSLv3 connection in order to gain information that
      they shouldn't have been able to get. The best solution here is to
      upgrade to OpenSSL 0.9.8s or 1.0.0f (or later). But when building
      or running with a non-upgraded OpenSSL, we disable SSLv3 entirely
      to make sure that the bug can't happen.
    - Never use a bridge or a controller-supplied node as an exit, even
      if its exit policy allows it. Found by wanoskarnet. Fixes bug
      5342. Bugfix on 0.1.1.15-rc (for controller-purpose descriptors)
      and 0.2.0.3-alpha (for bridge-purpose descriptors).
    - Only build circuits if we have a sufficient threshold of the total
      descriptors that are marked in the consensus with the "Exit"
      flag. This mitigates an attack proposed by wanoskarnet, in which
      all of a client's bridges collude to restrict the exit nodes that
      the client knows about. Fixes bug 5343.
    - Provide controllers with a safer way to implement the cookie
      authentication mechanism. With the old method, if another locally
      running program could convince a controller that it was the Tor
      process, then that program could trick the controller into telling
      it the contents of an arbitrary 32-byte file. The new "SAFECOOKIE"
      authentication method uses a challenge-response approach to prevent
      this attack. Fixes bug 5185; implements proposal 193.

  o Major bugfixes:
    - Avoid logging uninitialized data when unable to decode a hidden
      service descriptor cookie. Fixes bug 5647; bugfix on 0.2.1.5-alpha.
    - Avoid a client-side assertion failure when receiving an INTRODUCE2
      cell on a general purpose circuit. Fixes bug 5644; bugfix on
      0.2.1.6-alpha.
    - Fix builds when the path to sed, openssl, or sha1sum contains
      spaces, which is pretty common on Windows. Fixes bug 5065; bugfix
      on 0.2.2.1-alpha.
    - Correct our replacements for the timeradd() and timersub() functions
      on platforms that lack them (for example, Windows). The timersub()
      function is used when expiring circuits, while timeradd() is
      currently unused. Bug report and patch by Vektor. Fixes bug 4778;
      bugfix on 0.2.2.24-alpha.
    - Fix the SOCKET_OK test that we use to tell when socket
      creation fails so that it works on Win64. Fixes part of bug 4533;
      bugfix on 0.2.2.29-beta. Bug found by wanoskarnet.

  o Minor bugfixes:
    - Reject out-of-range times like 23:59:61 in parse_rfc1123_time().
      Fixes bug 5346; bugfix on 0.0.8pre3.
    - Make our number-parsing functions always treat too-large values
      as an error, even when those values exceed the width of the
      underlying type. Previously, if the caller provided these
      functions with minima or maxima set to the extreme values of the
      underlying integer type, these functions would return those
      values on overflow rather than treating overflow as an error.
      Fixes part of bug 5786; bugfix on 0.0.9.
    - Older Linux kernels erroneously respond to strange nmap behavior
      by having accept() return successfully with a zero-length
      socket. When this happens, just close the connection. Previously,
      we would try harder to learn the remote address: but there was
      no such remote address to learn, and our method for trying to
      learn it was incorrect. Fixes bugs 1240, 4745, and 4747. Bugfix
      on 0.1.0.3-rc. Reported and diagnosed by "r1eo".
    - Correct parsing of certain date types in parse_http_time().
      Without this patch, If-Modified-Since would behave
      incorrectly. Fixes bug 5346; bugfix on 0.2.0.2-alpha. Patch from
      Esteban Manchado Velázques.
    - Change the BridgePassword feature (part of the "bridge community"
      design, which is not yet implemented) to use a time-independent
      comparison. The old behavior might have allowed an adversary
      to use timing to guess the BridgePassword value. Fixes bug 5543;
      bugfix on 0.2.0.14-alpha.
    - Detect and reject certain misformed escape sequences in
      configuration values. Previously, these values would cause us
      to crash if received in a torrc file or over an authenticated
      control port. Bug found by Esteban Manchado Velázquez, and
      independently by Robert Connolly from Matta Consulting who further
      noted that it allows a post-authentication heap overflow. Patch
      by Alexander Schrijver. Fixes bugs 5090 and 5402 (CVE 2012-1668);
      bugfix on 0.2.0.16-alpha.
    - Fix a compile warning when using the --enable-openbsd-malloc
      configure option. Fixes bug 5340; bugfix on 0.2.0.20-rc.
    - During configure, detect when we're building with clang version
      3.0 or lower and disable the -Wnormalized=id and -Woverride-init
      CFLAGS. clang doesn't support them yet.
    - When sending an HTTP/1.1 proxy request, include a Host header.
      Fixes bug 5593; bugfix on 0.2.2.1-alpha.
    - Fix a NULL-pointer dereference on a badly formed SETCIRCUITPURPOSE
      command. Found by mikeyc. Fixes bug 5796; bugfix on 0.2.2.9-alpha.
    - If we hit the error case where routerlist_insert() replaces an
      existing (old) server descriptor, make sure to remove that
      server descriptor from the old_routers list. Fix related to bug
      1776. Bugfix on 0.2.2.18-alpha.

  o Minor bugfixes (documentation and log messages):
    - Fix a typo in a log message in rend_service_rendezvous_has_opened().
      Fixes bug 4856; bugfix on Tor 0.0.6.
    - Update "ClientOnly" man page entry to explain that there isn't
      really any point to messing with it. Resolves ticket 5005.
    - Document the GiveGuardFlagTo_CVE_2011_2768_VulnerableRelays
      directory authority option (introduced in Tor 0.2.2.34).
    - Downgrade the "We're missing a certificate" message from notice
      to info: people kept mistaking it for a real problem, whereas it
      is seldom the problem even when we are failing to bootstrap. Fixes
      bug 5067; bugfix on 0.2.0.10-alpha.
    - Correctly spell "connect" in a log message on failure to create a
      controlsocket. Fixes bug 4803; bugfix on 0.2.2.26-beta.
    - Clarify the behavior of MaxCircuitDirtiness with hidden service
      circuits. Fixes issue 5259.

  o Minor features:
    - Directory authorities now reject versions of Tor older than
      0.2.1.30, and Tor versions between 0.2.2.1-alpha and 0.2.2.20-alpha
      inclusive. These versions accounted for only a small fraction of
      the Tor network, and have numerous known security issues. Resolves
      issue 4788.
    - Update to the May 1 2012 Maxmind GeoLite Country database.

  - Feature removal:
    - When sending or relaying a RELAY_EARLY cell, we used to convert
      it to a RELAY cell if the connection was using the v1 link
      protocol. This was a workaround for older versions of Tor, which
      didn't handle RELAY_EARLY cells properly. Now that all supported
      versions can handle RELAY_EARLY cells, and now that we're enforcing
      the "no RELAY_EXTEND commands except in RELAY_EARLY cells" rule,
      remove this workaround. Addresses bug 4786.


Changes in version 0.2.2.35 - 2011-12-16
  Tor 0.2.2.35 fixes a critical heap-overflow security issue in Tor's
  buffers code. Absolutely everybody should upgrade.

  The bug relied on an incorrect calculation when making data continuous
  in one of our IO buffers, if the first chunk of the buffer was
  misaligned by just the wrong amount. The miscalculation would allow an
  attacker to overflow a piece of heap-allocated memory. To mount this
  attack, the attacker would need to either open a SOCKS connection to
  Tor's SocksPort (usually restricted to localhost), or target a Tor
  instance configured to make its connections through a SOCKS proxy
  (which Tor does not do by default).

  Good security practice requires that all heap-overflow bugs should be
  presumed to be exploitable until proven otherwise, so we are treating
  this as a potential code execution attack. Please upgrade immediately!
  This bug does not affect bufferevents-based builds of Tor. Special
  thanks to "Vektor" for reporting this issue to us!

  Tor 0.2.2.35 also fixes several bugs in previous versions, including
  crash bugs for unusual configurations, and a long-term bug that
  would prevent Tor from starting on Windows machines with draconian
  AV software.

  With this release, we remind everyone that 0.2.0.x has reached its
  formal end-of-life. Those Tor versions have many known flaws, and
  nobody should be using them. You should upgrade -- ideally to the
  0.2.2.x series. If you're using a Linux or BSD and its packages are
  obsolete, stop using those packages and upgrade anyway.

  The Tor 0.2.1.x series is also approaching its end-of-life: it will no
  longer receive support after some time in early 2012.

  o Major bugfixes:
    - Fix a heap overflow bug that could occur when trying to pull
      data into the first chunk of a buffer, when that chunk had
      already had some data drained from it. Fixes CVE-2011-2778;
      bugfix on 0.2.0.16-alpha. Reported by "Vektor".
    - Initialize Libevent with the EVENT_BASE_FLAG_NOLOCK flag enabled, so
      that it doesn't attempt to allocate a socketpair. This could cause
      some problems on Windows systems with overzealous firewalls. Fix for
      bug 4457; workaround for Libevent versions 2.0.1-alpha through
      2.0.15-stable.
    - If we mark an OR connection for close based on a cell we process,
      don't process any further cells on it. We already avoid further
      reads on marked-for-close connections, but now we also discard the
      cells we'd already read. Fixes bug 4299; bugfix on 0.2.0.10-alpha,
      which was the first version where we might mark a connection for
      close based on processing a cell on it.
    - Correctly sanity-check that we don't underflow on a memory
      allocation (and then assert) for hidden service introduction
      point decryption. Bug discovered by Dan Rosenberg. Fixes bug 4410;
      bugfix on 0.2.1.5-alpha.
    - Fix a memory leak when we check whether a hidden service
      descriptor has any usable introduction points left. Fixes bug
      4424. Bugfix on 0.2.2.25-alpha.
    - Don't crash when we're running as a relay and don't have a GeoIP
      file. Bugfix on 0.2.2.34; fixes bug 4340. This backports a fix
      we've had in the 0.2.3.x branch already.
    - When running as a client, do not print a misleading (and plain
      wrong) log message that we're collecting "directory request"
      statistics: clients don't collect statistics. Also don't create a
      useless (because empty) stats file in the stats/ directory. Fixes
      bug 4353; bugfix on 0.2.2.34.

  o Minor bugfixes:
    - Detect failure to initialize Libevent. This fix provides better
      detection for future instances of bug 4457.
    - Avoid frequent calls to the fairly expensive cull_wedged_cpuworkers
      function. This was eating up hideously large amounts of time on some
      busy servers. Fixes bug 4518; bugfix on 0.0.9.8.
    - Resolve an integer overflow bug in smartlist_ensure_capacity().
      Fixes bug 4230; bugfix on Tor 0.1.0.1-rc. Based on a patch by
      Mansour Moufid.
    - Don't warn about unused log_mutex in log.c when building with
      --disable-threads using a recent GCC. Fixes bug 4437; bugfix on
      0.1.0.6-rc which introduced --disable-threads.
    - When configuring, starting, or stopping an NT service, stop
      immediately after the service configuration attempt has succeeded
      or failed. Fixes bug 3963; bugfix on 0.2.0.7-alpha.
    - When sending a NETINFO cell, include the original address
      received for the other side, not its canonical address. Found
      by "troll_un"; fixes bug 4349; bugfix on 0.2.0.10-alpha.
    - Fix a typo in a hibernation-related log message. Fixes bug 4331;
      bugfix on 0.2.2.23-alpha; found by "tmpname0901".
    - Fix a memory leak in launch_direct_bridge_descriptor_fetch() that
      occurred when a client tried to fetch a descriptor for a bridge
      in ExcludeNodes. Fixes bug 4383; bugfix on 0.2.2.25-alpha.
    - Backport fixes for a pair of compilation warnings on Windows.
      Fixes bug 4521; bugfix on 0.2.2.28-beta and on 0.2.2.29-beta.
    - If we had ever tried to call tor_addr_to_str on an address of
      unknown type, we would have done a strdup on an uninitialized
      buffer. Now we won't. Fixes bug 4529; bugfix on 0.2.1.3-alpha.
      Reported by "troll_un".
    - Correctly detect and handle transient lookup failures from
      tor_addr_lookup. Fixes bug 4530; bugfix on 0.2.1.5-alpha.
      Reported by "troll_un".
    - Fix null-pointer access that could occur if TLS allocation failed.
      Fixes bug 4531; bugfix on 0.2.0.20-rc. Found by "troll_un".
    - Use tor_socket_t type for listener argument to accept(). Fixes bug
      4535; bugfix on 0.2.2.28-beta. Found by "troll_un".

  o Minor features:
    - Add two new config options for directory authorities:
      AuthDirFastGuarantee sets a bandwidth threshold for guaranteeing the
      Fast flag, and AuthDirGuardBWGuarantee sets a bandwidth threshold
      that is always sufficient to satisfy the bandwidth requirement for
      the Guard flag. Now it will be easier for researchers to simulate
      Tor networks with different values. Resolves ticket 4484.
    - When Tor ignores a hidden service specified in its configuration,
      include the hidden service's directory in the warning message.
      Previously, we would only tell the user that some hidden service
      was ignored. Bugfix on 0.0.6; fixes bug 4426.
    - Update to the December 6 2011 Maxmind GeoLite Country database.

  o Packaging changes:
    - Make it easier to automate expert package builds on Windows,
      by removing an absolute path from makensis.exe command.


Changes in version 0.2.1.32 - 2011-12-16
  Tor 0.2.1.32 backports important security and privacy fixes for
  oldstable. This release is intended only for package maintainers and
  others who cannot use the 0.2.2 stable series. All others should be
  using Tor 0.2.2.x or newer.

  The Tor 0.2.1.x series will reach formal end-of-life some time in
  early 2012; we will stop releasing patches for it then.

  o Major bugfixes (also included in 0.2.2.x):
    - Correctly sanity-check that we don't underflow on a memory
      allocation (and then assert) for hidden service introduction
      point decryption. Bug discovered by Dan Rosenberg. Fixes bug 4410;
      bugfix on 0.2.1.5-alpha.
    - Fix a heap overflow bug that could occur when trying to pull
      data into the first chunk of a buffer, when that chunk had
      already had some data drained from it. Fixes CVE-2011-2778;
      bugfix on 0.2.0.16-alpha. Reported by "Vektor".

  o Minor features:
    - Update to the December 6 2011 Maxmind GeoLite Country database.


Changes in version 0.2.2.34 - 2011-10-26
  Tor 0.2.2.34 fixes a critical anonymity vulnerability where an attacker
  can deanonymize Tor users. Everybody should upgrade.

  The attack relies on four components: 1) Clients reuse their TLS cert
  when talking to different relays, so relays can recognize a user by
  the identity key in her cert. 2) An attacker who knows the client's
  identity key can probe each guard relay to see if that identity key
  is connected to that guard relay right now. 3) A variety of active
  attacks in the literature (starting from "Low-Cost Traffic Analysis
  of Tor" by Murdoch and Danezis in 2005) allow a malicious website to
  discover the guard relays that a Tor user visiting the website is using.
  4) Clients typically pick three guards at random, so the set of guards
  for a given user could well be a unique fingerprint for her. This
  release fixes components #1 and #2, which is enough to block the attack;
  the other two remain as open research problems. Special thanks to
  "frosty_un" for reporting the issue to us!

  Clients should upgrade so they are no longer recognizable by the TLS
  certs they present. Relays should upgrade so they no longer allow a
  remote attacker to probe them to test whether unpatched clients are
  currently connected to them.

  This release also fixes several vulnerabilities that allow an attacker
  to enumerate bridge relays. Some bridge enumeration attacks still
  remain; see for example proposal 188.

  o Privacy/anonymity fixes (clients):
    - Clients and bridges no longer send TLS certificate chains on
      outgoing OR connections. Previously, each client or bridge would
      use the same cert chain for all outgoing OR connections until
      its IP address changes, which allowed any relay that the client
      or bridge contacted to determine which entry guards it is using.
      Fixes CVE-2011-2768. Bugfix on 0.0.9pre5; found by "frosty_un".
    - If a relay receives a CREATE_FAST cell on a TLS connection, it
      no longer considers that connection as suitable for satisfying a
      circuit EXTEND request. Now relays can protect clients from the
      CVE-2011-2768 issue even if the clients haven't upgraded yet.
    - Directory authorities no longer assign the Guard flag to relays
      that haven't upgraded to the above "refuse EXTEND requests
      to client connections" fix. Now directory authorities can
      protect clients from the CVE-2011-2768 issue even if neither
      the clients nor the relays have upgraded yet. There's a new
      "GiveGuardFlagTo_CVE_2011_2768_VulnerableRelays" config option
      to let us transition smoothly, else tomorrow there would be no
      guard relays.

  o Privacy/anonymity fixes (bridge enumeration):
    - Bridge relays now do their directory fetches inside Tor TLS
      connections, like all the other clients do, rather than connecting
      directly to the DirPort like public relays do. Removes another
      avenue for enumerating bridges. Fixes bug 4115; bugfix on 0.2.0.35.
    - Bridges relays now build circuits for themselves in a more similar
      way to how clients build them. Removes another avenue for
      enumerating bridges. Fixes bug 4124; bugfix on 0.2.0.3-alpha,
      when bridges were introduced.
    - Bridges now refuse CREATE or CREATE_FAST cells on OR connections
      that they initiated. Relays could distinguish incoming bridge
      connections from client connections, creating another avenue for
      enumerating bridges. Fixes CVE-2011-2769. Bugfix on 0.2.0.3-alpha.
      Found by "frosty_un".

  o Major bugfixes:
    - Fix a crash bug when changing node restrictions while a DNS lookup
      is in-progress. Fixes bug 4259; bugfix on 0.2.2.25-alpha. Bugfix
      by "Tey'".
    - Don't launch a useless circuit after failing to use one of a
      hidden service's introduction points. Previously, we would
      launch a new introduction circuit, but not set the hidden service
      which that circuit was intended to connect to, so it would never
      actually be used. A different piece of code would then create a
      new introduction circuit correctly. Bug reported by katmagic and
      found by Sebastian Hahn. Bugfix on 0.2.1.13-alpha; fixes bug 4212.

  o Minor bugfixes:
    - Change an integer overflow check in the OpenBSD_Malloc code so
      that GCC is less likely to eliminate it as impossible. Patch
      from Mansour Moufid. Fixes bug 4059.
    - When a hidden service turns an extra service-side introduction
      circuit into a general-purpose circuit, free the rend_data and
      intro_key fields first, so we won't leak memory if the circuit
      is cannibalized for use as another service-side introduction
      circuit. Bugfix on 0.2.1.7-alpha; fixes bug 4251.
    - Bridges now skip DNS self-tests, to act a little more stealthily.
      Fixes bug 4201; bugfix on 0.2.0.3-alpha, which first introduced
      bridges. Patch by "warms0x".
    - Fix internal bug-checking logic that was supposed to catch
      failures in digest generation so that it will fail more robustly
      if we ask for a nonexistent algorithm. Found by Coverity Scan.
      Bugfix on 0.2.2.1-alpha; fixes Coverity CID 479.
    - Report any failure in init_keys() calls launched because our
      IP address has changed. Spotted by Coverity Scan. Bugfix on
      0.1.1.4-alpha; fixes CID 484.

  o Minor bugfixes (log messages and documentation):
    - Remove a confusing dollar sign from the example fingerprint in the
      man page, and also make the example fingerprint a valid one. Fixes
      bug 4309; bugfix on 0.2.1.3-alpha.
    - The next version of Windows will be called Windows 8, and it has
      a major version of 6, minor version of 2. Correctly identify that
      version instead of calling it "Very recent version". Resolves
      ticket 4153; reported by funkstar.
    - Downgrade log messages about circuit timeout calibration from
      "notice" to "info": they don't require or suggest any human
      intervention. Patch from Tom Lowenthal. Fixes bug 4063;
      bugfix on 0.2.2.14-alpha.

  o Minor features:
    - Turn on directory request statistics by default and include them in
      extra-info descriptors. Don't break if we have no GeoIP database.
      Backported from 0.2.3.1-alpha; implements ticket 3951.
    - Update to the October 4 2011 Maxmind GeoLite Country database.


Changes in version 0.2.1.31 - 2011-10-26
  Tor 0.2.1.31 backports important security and privacy fixes for
  oldstable. This release is intended only for package maintainers and
  others who cannot use the 0.2.2 stable series. All others should be
  using Tor 0.2.2.x or newer.

  o Security fixes (also included in 0.2.2.x):
    - Replace all potentially sensitive memory comparison operations
      with versions whose runtime does not depend on the data being
      compared. This will help resist a class of attacks where an
      adversary can use variations in timing information to learn
      sensitive data. Fix for one case of bug 3122. (Safe memcmp
      implementation by Robert Ransom based partially on code by DJB.)
    - Fix an assert in parsing router descriptors containing IPv6
      addresses. This one took down the directory authorities when
      somebody tried some experimental code. Bugfix on 0.2.1.3-alpha.

  o Privacy/anonymity fixes (also included in 0.2.2.x):
    - Clients and bridges no longer send TLS certificate chains on
      outgoing OR connections. Previously, each client or bridge would
      use the same cert chain for all outgoing OR connections until
      its IP address changes, which allowed any relay that the client
      or bridge contacted to determine which entry guards it is using.
      Fixes CVE-2011-2768. Bugfix on 0.0.9pre5; found by "frosty_un".
    - If a relay receives a CREATE_FAST cell on a TLS connection, it
      no longer considers that connection as suitable for satisfying a
      circuit EXTEND request. Now relays can protect clients from the
      CVE-2011-2768 issue even if the clients haven't upgraded yet.
    - Bridges now refuse CREATE or CREATE_FAST cells on OR connections
      that they initiated. Relays could distinguish incoming bridge 
      connections from client connections, creating another avenue for
      enumerating bridges. Fixes CVE-2011-2769. Bugfix on 0.2.0.3-alpha.
      Found by "frosty_un".
    - When receiving a hidden service descriptor, check that it is for
      the hidden service we wanted. Previously, Tor would store any
      hidden service descriptors that a directory gave it, whether it
      wanted them or not. This wouldn't have let an attacker impersonate
      a hidden service, but it did let directories pre-seed a client
      with descriptors that it didn't want. Bugfix on 0.0.6.
    - Avoid linkability based on cached hidden service descriptors: forget
      all hidden service descriptors cached as a client when processing a
      SIGNAL NEWNYM command. Fixes bug 3000; bugfix on 0.0.6.
    - Make the bridge directory authority refuse to answer directory
      requests for "all" descriptors. It used to include bridge
      descriptors in its answer, which was a major information leak.
      Found by "piebeer". Bugfix on 0.2.0.3-alpha.
    - Don't attach new streams to old rendezvous circuits after SIGNAL
      NEWNYM. Previously, we would keep using an existing rendezvous
      circuit if it remained open (i.e. if it were kept open by a
      long-lived stream, or if a new stream were attached to it before
      Tor could notice that it was old and no longer in use). Bugfix on
      0.1.1.15-rc; fixes bug 3375.

  o Minor bugfixes (also included in 0.2.2.x):
    - When we restart our relay, we might get a successful connection
      from the outside before we've started our reachability tests,
      triggering a warning: "ORPort found reachable, but I have no
      routerinfo yet. Failing to inform controller of success." This
      bug was harmless unless Tor is running under a controller
      like Vidalia, in which case the controller would never get a
      REACHABILITY_SUCCEEDED status event. Bugfix on 0.1.2.6-alpha;
      fixes bug 1172.
    - Build correctly on OSX with zlib 1.2.4 and higher with all warnings
      enabled. Fixes bug 1526.
    - Remove undocumented option "-F" from tor-resolve: it hasn't done
      anything since 0.2.1.16-rc.
    - Avoid signed/unsigned comparisons by making SIZE_T_CEILING unsigned.
      None of the cases where we did this before were wrong, but by making
      this change we avoid warnings. Fixes bug 2475; bugfix on 0.2.1.28.
    - Fix a rare crash bug that could occur when a client was configured
      with a large number of bridges. Fixes bug 2629; bugfix on
      0.2.1.2-alpha. Bugfix by trac user "shitlei".
    - Correct the warning displayed when a rendezvous descriptor exceeds
      the maximum size. Fixes bug 2750; bugfix on 0.2.1.5-alpha. Found by
      John Brooks.
    - Fix an uncommon assertion failure when running with DNSPort under
      heavy load. Fixes bug 2933; bugfix on 0.2.0.1-alpha.
    - When warning about missing zlib development packages during compile,
      give the correct package names. Bugfix on 0.2.0.1-alpha.
    - Require that introduction point keys and onion keys have public
      exponent 65537. Bugfix on 0.2.0.10-alpha.
    - Do not crash when our configuration file becomes unreadable, for
      example due to a permissions change, between when we start up
      and when a controller calls SAVECONF. Fixes bug 3135; bugfix
      on 0.0.9pre6.
    - Fix warnings from GCC 4.6's "-Wunused-but-set-variable" option.
      Fixes bug 3208.
    - Always NUL-terminate the sun_path field of a sockaddr_un before
      passing it to the kernel. (Not a security issue: kernels are
      smart enough to reject bad sockaddr_uns.) Found by Coverity;
      CID #428. Bugfix on Tor 0.2.0.3-alpha.
    - Don't stack-allocate the list of supplementary GIDs when we're
      about to log them. Stack-allocating NGROUPS_MAX gid_t elements
      could take up to 256K, which is way too much stack. Found by
      Coverity; CID #450. Bugfix on 0.2.1.7-alpha.

  o Minor bugfixes (only in 0.2.1.x):
    - Resume using micro-version numbers in 0.2.1.x: our Debian packages
      rely on them. Bugfix on 0.2.1.30.
    - Use git revisions instead of svn revisions when generating our
      micro-version numbers. Bugfix on 0.2.1.15-rc; fixes bug 2402.

  o Minor features (also included in 0.2.2.x):
    - Adjust the expiration time on our SSL session certificates to
      better match SSL certs seen in the wild. Resolves ticket 4014.
    - Allow nameservers with IPv6 address. Resolves bug 2574.
    - Update to the October 4 2011 Maxmind GeoLite Country database.


Changes in version 0.2.2.33 - 2011-09-13
  Tor 0.2.2.33 fixes several bugs, and includes a slight tweak to Tor's
  TLS handshake that makes relays and bridges that run this new version
  reachable from Iran again.

  o Major bugfixes:
    - Avoid an assertion failure when reloading a configuration with
      TrackExitHosts changes. Found and fixed by 'laruldan'. Fixes bug
      3923; bugfix on 0.2.2.25-alpha.

  o Minor features (security):
    - Check for replays of the public-key encrypted portion of an
      INTRODUCE1 cell, in addition to the current check for replays of
      the g^x value. This prevents a possible class of active attacks
      by an attacker who controls both an introduction point and a
      rendezvous point, and who uses the malleability of AES-CTR to
      alter the encrypted g^x portion of the INTRODUCE1 cell. We think
      that these attacks are infeasible (requiring the attacker to send
      on the order of zettabytes of altered cells in a short interval),
      but we'd rather block them off in case there are any classes of
      this attack that we missed. Reported by Willem Pinckaers.

  o Minor features:
    - Adjust the expiration time on our SSL session certificates to
      better match SSL certs seen in the wild. Resolves ticket 4014.
    - Change the default required uptime for a relay to be accepted as
      a HSDir (hidden service directory) from 24 hours to 25 hours.
      Improves on 0.2.0.10-alpha; resolves ticket 2649.
    - Add a VoteOnHidServDirectoriesV2 config option to allow directory
      authorities to abstain from voting on assignment of the HSDir
      consensus flag. Related to bug 2649.
    - Update to the September 6 2011 Maxmind GeoLite Country database.

  o Minor bugfixes (documentation and log messages):
    - Correct the man page to explain that HashedControlPassword and
      CookieAuthentication can both be set, in which case either method
      is sufficient to authenticate to Tor. Bugfix on 0.2.0.7-alpha,
      when we decided to allow these config options to both be set. Issue
      raised by bug 3898.
    - Demote the 'replay detected' log message emitted when a hidden
      service receives the same Diffie-Hellman public key in two different
      INTRODUCE2 cells to info level. A normal Tor client can cause that
      log message during its normal operation. Bugfix on 0.2.1.6-alpha;
      fixes part of bug 2442.
    - Demote the 'INTRODUCE2 cell is too {old,new}' log message to info
      level. There is nothing that a hidden service's operator can do
      to fix its clients' clocks. Bugfix on 0.2.1.6-alpha; fixes part
      of bug 2442.
    - Clarify a log message specifying the characters permitted in
      HiddenServiceAuthorizeClient client names. Previously, the log
      message said that "[A-Za-z0-9+-_]" were permitted; that could have
      given the impression that every ASCII character between "+" and "_"
      was permitted. Now we say "[A-Za-z0-9+_-]". Bugfix on 0.2.1.5-alpha.

  o Build fixes:
    - Provide a substitute implementation of lround() for MSVC, which
      apparently lacks it. Patch from Gisle Vanem.
    - Clean up some code issues that prevented Tor from building on older
      BSDs. Fixes bug 3894; reported by "grarpamp".
    - Search for a platform-specific version of "ar" when cross-compiling.
      Should fix builds on iOS. Resolves bug 3909, found by Marco Bonetti.


Changes in version 0.2.2.32 - 2011-08-27
  The Tor 0.2.2 release series is dedicated to the memory of Andreas
  Pfitzmann (1958-2010), a pioneer in anonymity and privacy research,
  a founder of the PETS community, a leader in our field, a mentor,
  and a friend. He left us with these words: "I had the possibility
  to contribute to this world that is not as it should be. I hope I
  could help in some areas to make the world a better place, and that
  I could also encourage other people to be engaged in improving the
  world. Please, stay engaged. This world needs you, your love, your
  initiative -- now I cannot be part of that anymore."

  Tor 0.2.2.32, the first stable release in the 0.2.2 branch, is finally
  ready. More than two years in the making, this release features improved
  client performance and hidden service reliability, better compatibility
  for Android, correct behavior for bridges that listen on more than
  one address, more extensible and flexible directory object handling,
  better reporting of network statistics, improved code security, and
  many many other features and bugfixes.

  o Major features (client performance):
    - When choosing which cells to relay first, relays now favor circuits
      that have been quiet recently, to provide lower latency for
      low-volume circuits. By default, relays enable or disable this
      feature based on a setting in the consensus. They can override
      this default by using the new "CircuitPriorityHalflife" config
      option. Design and code by Ian Goldberg, Can Tang, and Chris
      Alexander.
    - Directory authorities now compute consensus weightings that instruct
      clients how to weight relays flagged as Guard, Exit, Guard+Exit,
      and no flag. Clients use these weightings to distribute network load
      more evenly across these different relay types. The weightings are
      in the consensus so we can change them globally in the future. Extra
      thanks to "outofwords" for finding some nasty security bugs in
      the first implementation of this feature.

  o Major features (client performance, circuit build timeout):
    - Tor now tracks how long it takes to build client-side circuits
      over time, and adapts its timeout to local network performance.
      Since a circuit that takes a long time to build will also provide
      bad performance, we get significant latency improvements by
      discarding the slowest 20% of circuits. Specifically, Tor creates
      circuits more aggressively than usual until it has enough data
      points for a good timeout estimate. Implements proposal 151.
    - Circuit build timeout constants can be controlled by consensus
      parameters. We set good defaults for these parameters based on
      experimentation on broadband and simulated high-latency links.
    - Circuit build time learning can be disabled via consensus parameter
      or by the client via a LearnCircuitBuildTimeout config option. We
      also automatically disable circuit build time calculation if either
      AuthoritativeDirectory is set, or if we fail to write our state
      file. Implements ticket 1296.

  o Major features (relays use their capacity better):
    - Set SO_REUSEADDR socket option on all sockets, not just
      listeners. This should help busy exit nodes avoid running out of
      useable ports just because all the ports have been used in the
      near past. Resolves issue 2850.
    - Relays now save observed peak bandwidth throughput rates to their
      state file (along with total usage, which was already saved),
      so that they can determine their correct estimated bandwidth on
      restart. Resolves bug 1863, where Tor relays would reset their
      estimated bandwidth to 0 after restarting.
    - Lower the maximum weighted-fractional-uptime cutoff to 98%. This
      should give us approximately 40-50% more Guard-flagged nodes,
      improving the anonymity the Tor network can provide and also
      decreasing the dropoff in throughput that relays experience when
      they first get the Guard flag.
    - Directory authorities now take changes in router IP address and
      ORPort into account when determining router stability. Previously,
      if a router changed its IP or ORPort, the authorities would not
      treat it as having any downtime for the purposes of stability
      calculation, whereas clients would experience downtime since the
      change would take a while to propagate to them. Resolves issue 1035.
    - New AccelName and AccelDir options add support for dynamic OpenSSL
      hardware crypto acceleration engines.

  o Major features (relays control their load better):
    - Exit relays now try harder to block exit attempts from unknown
      relays, to make it harder for people to use them as one-hop proxies
      a la tortunnel. Controlled by the refuseunknownexits consensus
      parameter (currently enabled), or you can override it on your
      relay with the RefuseUnknownExits torrc option. Resolves bug 1751;
      based on a variant of proposal 163.
    - Add separate per-conn write limiting to go with the per-conn read
      limiting. We added a global write limit in Tor 0.1.2.5-alpha,
      but never per-conn write limits.
    - New consensus params "bwconnrate" and "bwconnburst" to let us
      rate-limit client connections as they enter the network. It's
      controlled in the consensus so we can turn it on and off for
      experiments. It's starting out off. Based on proposal 163.

  o Major features (controllers):
    - Export GeoIP information on bridge usage to controllers even if we
      have not yet been running for 24 hours. Now Vidalia bridge operators
      can get more accurate and immediate feedback about their
      contributions to the network.
    - Add an __OwningControllerProcess configuration option and a
      TAKEOWNERSHIP control-port command. Now a Tor controller can ensure
      that when it exits, Tor will shut down. Implements feature 3049.

  o Major features (directory authorities):
    - Directory authorities now create, vote on, and serve multiple
      parallel formats of directory data as part of their voting process.
      Partially implements Proposal 162: "Publish the consensus in
      multiple flavors".
    - Directory authorities now agree on and publish small summaries
      of router information that clients can use in place of regular
      server descriptors. This transition will allow Tor 0.2.3 clients
      to use far less bandwidth for downloading information about the
      network. Begins the implementation of Proposal 158: "Clients
      download consensus + microdescriptors".
    - The directory voting system is now extensible to use multiple hash
      algorithms for signatures and resource selection. Newer formats
      are signed with SHA256, with a possibility for moving to a better
      hash algorithm in the future.
    - Directory authorities can now vote on arbitary integer values as
      part of the consensus process. This is designed to help set
      network-wide parameters. Implements proposal 167.

  o Major features and bugfixes (node selection):
    - Revise and reconcile the meaning of the ExitNodes, EntryNodes,
      ExcludeEntryNodes, ExcludeExitNodes, ExcludeNodes, and Strict*Nodes
      options. Previously, we had been ambiguous in describing what
      counted as an "exit" node, and what operations exactly "StrictNodes
      0" would permit. This created confusion when people saw nodes built
      through unexpected circuits, and made it hard to tell real bugs from
      surprises. Now the intended behavior is:
        . "Exit", in the context of ExitNodes and ExcludeExitNodes, means
          a node that delivers user traffic outside the Tor network.
        . "Entry", in the context of EntryNodes, means a node used as the
          first hop of a multihop circuit. It doesn't include direct
          connections to directory servers.
        . "ExcludeNodes" applies to all nodes.
        . "StrictNodes" changes the behavior of ExcludeNodes only. When
          StrictNodes is set, Tor should avoid all nodes listed in
          ExcludeNodes, even when it will make user requests fail. When
          StrictNodes is *not* set, then Tor should follow ExcludeNodes
          whenever it can, except when it must use an excluded node to
          perform self-tests, connect to a hidden service, provide a
          hidden service, fulfill a .exit request, upload directory
          information, or fetch directory information.
      Collectively, the changes to implement the behavior fix bug 1090.
    - If EntryNodes, ExitNodes, ExcludeNodes, or ExcludeExitNodes
      change during a config reload, mark and discard all our origin
      circuits. This fix should address edge cases where we change the
      config options and but then choose a circuit that we created before
      the change.
    - Make EntryNodes config option much more aggressive even when
      StrictNodes is not set. Before it would prepend your requested
      entrynodes to your list of guard nodes, but feel free to use others
      after that. Now it chooses only from your EntryNodes if any of
      those are available, and only falls back to others if a) they're
      all down and b) StrictNodes is not set.
    - Now we refresh your entry guards from EntryNodes at each consensus
      fetch -- rather than just at startup and then they slowly rot as
      the network changes.
    - Add support for the country code "{??}" in torrc options like
      ExcludeNodes, to indicate all routers of unknown country. Closes
      bug 1094.
    - ExcludeNodes now takes precedence over EntryNodes and ExitNodes: if
      a node is listed in both, it's treated as excluded.
    - ExcludeNodes now applies to directory nodes -- as a preference if
      StrictNodes is 0, or an absolute requirement if StrictNodes is 1.
      Don't exclude all the directory authorities and set StrictNodes to 1
      unless you really want your Tor to break.
    - ExcludeNodes and ExcludeExitNodes now override exit enclaving.
    - ExcludeExitNodes now overrides .exit requests.
    - We don't use bridges listed in ExcludeNodes.
    - When StrictNodes is 1:
       . We now apply ExcludeNodes to hidden service introduction points
         and to rendezvous points selected by hidden service users. This
         can make your hidden service less reliable: use it with caution!
       . If we have used ExcludeNodes on ourself, do not try relay
         reachability self-tests.
       . If we have excluded all the directory authorities, we will not
         even try to upload our descriptor if we're a relay.
       . Do not honor .exit requests to an excluded node.
    - When the set of permitted nodes changes, we now remove any mappings
      introduced via TrackExitHosts to now-excluded nodes. Bugfix on
      0.1.0.1-rc.
    - We never cannibalize a circuit that had excluded nodes on it, even
      if StrictNodes is 0. Bugfix on 0.1.0.1-rc.
    - Improve log messages related to excluded nodes.

  o Major features (misc):
    - Numerous changes, bugfixes, and workarounds from Nathan Freitas
      to help Tor build correctly for Android phones.
    - The options SocksPort, ControlPort, and so on now all accept a
      value "auto" that opens a socket on an OS-selected port. A
      new ControlPortWriteToFile option tells Tor to write its
      actual control port or ports to a chosen file. If the option
      ControlPortFileGroupReadable is set, the file is created as
      group-readable. Now users can run two Tor clients on the same
      system without needing to manually mess with parameters. Resolves
      part of ticket 3076.
    - Tor now supports tunneling all of its outgoing connections over
      a SOCKS proxy, using the SOCKS4Proxy and/or SOCKS5Proxy
      configuration options. Code by Christopher Davis.

  o Code security improvements:
    - Replace all potentially sensitive memory comparison operations
      with versions whose runtime does not depend on the data being
      compared. This will help resist a class of attacks where an
      adversary can use variations in timing information to learn
      sensitive data. Fix for one case of bug 3122. (Safe memcmp
      implementation by Robert Ransom based partially on code by DJB.)
    - Enable Address Space Layout Randomization (ASLR) and Data Execution
      Prevention (DEP) by default on Windows to make it harder for
      attackers to exploit vulnerabilities. Patch from John Brooks.
    - New "--enable-gcc-hardening" ./configure flag (off by default)
      to turn on gcc compile time hardening options. It ensures
      that signed ints have defined behavior (-fwrapv), enables
      -D_FORTIFY_SOURCE=2 (requiring -O2), adds stack smashing protection
      with canaries (-fstack-protector-all), turns on ASLR protection if
      supported by the kernel (-fPIE, -pie), and adds additional security
      related warnings. Verified to work on Mac OS X and Debian Lenny.
    - New "--enable-linker-hardening" ./configure flag (off by default)
      to turn on ELF specific hardening features (relro, now). This does
      not work with Mac OS X or any other non-ELF binary format.
    - Always search the Windows system directory for system DLLs, and
      nowhere else. Bugfix on 0.1.1.23; fixes bug 1954.
    - New DisableAllSwap option. If set to 1, Tor will attempt to lock all
      current and future memory pages via mlockall(). On supported
      platforms (modern Linux and probably BSD but not Windows or OS X),
      this should effectively disable any and all attempts to page out
      memory. This option requires that you start your Tor as root --
      if you use DisableAllSwap, please consider using the User option
      to properly reduce the privileges of your Tor.

  o Major bugfixes (crashes):
    - Fix crash bug on platforms where gmtime and localtime can return
      NULL. Windows 7 users were running into this one. Fixes part of bug
      2077. Bugfix on all versions of Tor. Found by boboper.
    - Introduce minimum/maximum values that clients will believe
      from the consensus. Now we'll have a better chance to avoid crashes
      or worse when a consensus param has a weird value.
    - Fix a rare crash bug that could occur when a client was configured
      with a large number of bridges. Fixes bug 2629; bugfix on
      0.2.1.2-alpha. Bugfix by trac user "shitlei".
    - Do not crash when our configuration file becomes unreadable, for
      example due to a permissions change, between when we start up
      and when a controller calls SAVECONF. Fixes bug 3135; bugfix
      on 0.0.9pre6.
    - If we're in the pathological case where there's no exit bandwidth
      but there is non-exit bandwidth, or no guard bandwidth but there
      is non-guard bandwidth, don't crash during path selection. Bugfix
      on 0.2.0.3-alpha.
    - Fix a crash bug when trying to initialize the evdns module in
      Libevent 2. Bugfix on 0.2.1.16-rc.

  o Major bugfixes (stability):
    - Fix an assert in parsing router descriptors containing IPv6
      addresses. This one took down the directory authorities when
      somebody tried some experimental code. Bugfix on 0.2.1.3-alpha.
    - Fix an uncommon assertion failure when running with DNSPort under
      heavy load. Fixes bug 2933; bugfix on 0.2.0.1-alpha.
    - Treat an unset $HOME like an empty $HOME rather than triggering an
      assert. Bugfix on 0.0.8pre1; fixes bug 1522.
    - More gracefully handle corrupt state files, removing asserts
      in favor of saving a backup and resetting state.
    - Instead of giving an assertion failure on an internal mismatch
      on estimated freelist size, just log a BUG warning and try later.
      Mitigates but does not fix bug 1125.
    - Fix an assert that got triggered when using the TestingTorNetwork
      configuration option and then issuing a GETINFO config-text control
      command. Fixes bug 2250; bugfix on 0.2.1.2-alpha.
    - If the cached cert file is unparseable, warn but don't exit.

  o Privacy fixes (relays/bridges):
    - Don't list Windows capabilities in relay descriptors. We never made
      use of them, and maybe it's a bad idea to publish them. Bugfix
      on 0.1.1.8-alpha.
    - If the Nickname configuration option isn't given, Tor would pick a
      nickname based on the local hostname as the nickname for a relay.
      Because nicknames are not very important in today's Tor and the
      "Unnamed" nickname has been implemented, this is now problematic
      behavior: It leaks information about the hostname without being
      useful at all. Fixes bug 2979; bugfix on 0.1.2.2-alpha, which
      introduced the Unnamed nickname. Reported by tagnaq.
    - Maintain separate TLS contexts and certificates for incoming and
      outgoing connections in bridge relays. Previously we would use the
      same TLS contexts and certs for incoming and outgoing connections.
      Bugfix on 0.2.0.3-alpha; addresses bug 988.
    - Maintain separate identity keys for incoming and outgoing TLS
      contexts in bridge relays. Previously we would use the same
      identity keys for incoming and outgoing TLS contexts. Bugfix on
      0.2.0.3-alpha; addresses the other half of bug 988.
    - Make the bridge directory authority refuse to answer directory
      requests for "all descriptors". It used to include bridge
      descriptors in its answer, which was a major information leak.
      Found by "piebeer". Bugfix on 0.2.0.3-alpha.

  o Privacy fixes (clients):
    - When receiving a hidden service descriptor, check that it is for
      the hidden service we wanted. Previously, Tor would store any
      hidden service descriptors that a directory gave it, whether it
      wanted them or not. This wouldn't have let an attacker impersonate
      a hidden service, but it did let directories pre-seed a client
      with descriptors that it didn't want. Bugfix on 0.0.6.
    - Start the process of disabling ".exit" address notation, since it
      can be used for a variety of esoteric application-level attacks
      on users. To reenable it, set "AllowDotExit 1" in your torrc. Fix
      on 0.0.9rc5.
    - Reject attempts at the client side to open connections to private
      IP addresses (like 127.0.0.1, 10.0.0.1, and so on) with
      a randomly chosen exit node. Attempts to do so are always
      ill-defined, generally prevented by exit policies, and usually
      in error. This will also help to detect loops in transparent
      proxy configurations. You can disable this feature by setting
      "ClientRejectInternalAddresses 0" in your torrc.
    - Log a notice when we get a new control connection. Now it's easier
      for security-conscious users to recognize when a local application
      is knocking on their controller door. Suggested by bug 1196.

  o Privacy fixes (newnym):
    - Avoid linkability based on cached hidden service descriptors: forget
      all hidden service descriptors cached as a client when processing a
      SIGNAL NEWNYM command. Fixes bug 3000; bugfix on 0.0.6.
    - On SIGHUP, do not clear out all TrackHostExits mappings, client
      DNS cache entries, and virtual address mappings: that's what
      NEWNYM is for. Fixes bug 1345; bugfix on 0.1.0.1-rc.
    - Don't attach new streams to old rendezvous circuits after SIGNAL
      NEWNYM. Previously, we would keep using an existing rendezvous
      circuit if it remained open (i.e. if it were kept open by a
      long-lived stream, or if a new stream were attached to it before
      Tor could notice that it was old and no longer in use). Bugfix on
      0.1.1.15-rc; fixes bug 3375.

  o Major bugfixes (relay bandwidth accounting):
    - Fix a bug that could break accounting on 64-bit systems with large
      time_t values, making them hibernate for impossibly long intervals.
      Fixes bug 2146. Bugfix on 0.0.9pre6; fix by boboper.
    - Fix a bug in bandwidth accounting that could make us use twice
      the intended bandwidth when our interval start changes due to
      daylight saving time. Now we tolerate skew in stored vs computed
      interval starts: if the start of the period changes by no more than
      50% of the period's duration, we remember bytes that we transferred
      in the old period. Fixes bug 1511; bugfix on 0.0.9pre5.

  o Major bugfixes (bridges):
    - Bridges now use "reject *:*" as their default exit policy. Bugfix
      on 0.2.0.3-alpha. Fixes bug 1113.
    - If you configure your bridge with a known identity fingerprint,
      and the bridge authority is unreachable (as it is in at least
      one country now), fall back to directly requesting the descriptor
      from the bridge. Finishes the feature started in 0.2.0.10-alpha;
      closes bug 1138.
    - Fix a bug where bridge users who configure the non-canonical
      address of a bridge automatically switch to its canonical
      address. If a bridge listens at more than one address, it
      should be able to advertise those addresses independently and
      any non-blocked addresses should continue to work. Bugfix on Tor
      0.2.0.3-alpha. Fixes bug 2510.
    - If you configure Tor to use bridge A, and then quit and
      configure Tor to use bridge B instead (or if you change Tor
      to use bridge B via the controller), it would happily continue
      to use bridge A if it's still reachable. While this behavior is
      a feature if your goal is connectivity, in some scenarios it's a
      dangerous bug. Bugfix on Tor 0.2.0.1-alpha; fixes bug 2511.
    - When the controller configures a new bridge, don't wait 10 to 60
      seconds before trying to fetch its descriptor. Bugfix on
      0.2.0.3-alpha; fixes bug 3198 (suggested by 2355).

  o Major bugfixes (directory authorities):
    - Many relays have been falling out of the consensus lately because
      not enough authorities know about their descriptor for them to get
      a majority of votes. When we deprecated the v2 directory protocol,
      we got rid of the only way that v3 authorities can hear from each
      other about other descriptors. Now authorities examine every v3
      vote for new descriptors, and fetch them from that authority. Bugfix
      on 0.2.1.23.
    - Authorities could be tricked into giving out the Exit flag to relays
      that didn't allow exiting to any ports. This bug could screw
      with load balancing and stats. Bugfix on 0.1.1.6-alpha; fixes bug
      1238. Bug discovered by Martin Kowalczyk.
    - If all authorities restart at once right before a consensus vote,
      nobody will vote about "Running", and clients will get a consensus
      with no usable relays. Instead, authorities refuse to build a
      consensus if this happens. Bugfix on 0.2.0.10-alpha; fixes bug 1066.

  o Major bugfixes (stream-level fairness):
    - When receiving a circuit-level SENDME for a blocked circuit, try
      to package cells fairly from all the streams that had previously
      been blocked on that circuit. Previously, we had started with the
      oldest stream, and allowed each stream to potentially exhaust
      the circuit's package window. This gave older streams on any
      given circuit priority over newer ones. Fixes bug 1937. Detected
      originally by Camilo Viecco. This bug was introduced before the
      first Tor release, in svn commit r152: it is the new winner of
      the longest-lived bug prize.
    - Fix a stream fairness bug that would cause newer streams on a given
      circuit to get preference when reading bytes from the origin or
      destination. Fixes bug 2210. Fix by Mashael AlSabah. This bug was
      introduced before the first Tor release, in svn revision r152.
    - When the exit relay got a circuit-level sendme cell, it started
      reading on the exit streams, even if had 500 cells queued in the
      circuit queue already, so the circuit queue just grew and grew in
      some cases. We fix this by not re-enabling reading on receipt of a
      sendme cell when the cell queue is blocked. Fixes bug 1653. Bugfix
      on 0.2.0.1-alpha. Detected by Mashael AlSabah. Original patch by
      "yetonetime".
    - Newly created streams were allowed to read cells onto circuits,
      even if the circuit's cell queue was blocked and waiting to drain.
      This created potential unfairness, as older streams would be
      blocked, but newer streams would gladly fill the queue completely.
      We add code to detect this situation and prevent any stream from
      getting more than one free cell. Bugfix on 0.2.0.1-alpha. Partially
      fixes bug 1298.

  o Major bugfixes (hidden services):
    - Apply circuit timeouts to opened hidden-service-related circuits
      based on the correct start time. Previously, we would apply the
      circuit build timeout based on time since the circuit's creation;
      it was supposed to be applied based on time since the circuit
      entered its current state. Bugfix on 0.0.6; fixes part of bug 1297.
    - Improve hidden service robustness: When we find that we have
      extended a hidden service's introduction circuit to a relay not
      listed as an introduction point in the HS descriptor we currently
      have, retry with an introduction point from the current
      descriptor. Previously we would just give up. Fixes bugs 1024 and
      1930; bugfix on 0.2.0.10-alpha.
    - Directory authorities now use data collected from their own
      uptime observations when choosing whether to assign the HSDir flag
      to relays, instead of trusting the uptime value the relay reports in
      its descriptor. This change helps prevent an attack where a small
      set of nodes with frequently-changing identity keys can blackhole
      a hidden service. (Only authorities need upgrade; others will be
      fine once they do.) Bugfix on 0.2.0.10-alpha; fixes bug 2709.
    - Stop assigning the HSDir flag to relays that disable their
      DirPort (and thus will refuse to answer directory requests). This
      fix should dramatically improve the reachability of hidden services:
      hidden services and hidden service clients pick six HSDir relays
      to store and retrieve the hidden service descriptor, and currently
      about half of the HSDir relays will refuse to work. Bugfix on
      0.2.0.10-alpha; fixes part of bug 1693.

  o Major bugfixes (misc):
    - Clients now stop trying to use an exit node associated with a given
      destination by TrackHostExits if they fail to reach that exit node.
      Fixes bug 2999. Bugfix on 0.2.0.20-rc.
    - Fix a regression that caused Tor to rebind its ports if it receives
      SIGHUP while hibernating. Bugfix in 0.1.1.6-alpha; closes bug 919.
    - Remove an extra pair of quotation marks around the error
      message in control-port STATUS_GENERAL BUG events. Bugfix on
      0.1.2.6-alpha; fixes bug 3732.

  o Minor features (relays):
    - Ensure that no empty [dirreq-](read|write)-history lines are added
      to an extrainfo document. Implements ticket 2497.
    - When bandwidth accounting is enabled, be more generous with how
      much bandwidth we'll use up before entering "soft hibernation".
      Previously, we'd refuse new connections and circuits once we'd
      used up 95% of our allotment. Now, we use up 95% of our allotment,
      AND make sure that we have no more than 500MB (or 3 hours of
      expected traffic, whichever is lower) remaining before we enter
      soft hibernation.
    - Relays now log the reason for publishing a new relay descriptor,
      so we have a better chance of hunting down instances of bug 1810.
      Resolves ticket 3252.
    - Log a little more clearly about the times at which we're no longer
      accepting new connections (e.g. due to hibernating). Resolves
      bug 2181.
    - When AllowSingleHopExits is set, print a warning to explain to the
      relay operator why most clients are avoiding her relay.
    - Send END_STREAM_REASON_NOROUTE in response to EHOSTUNREACH errors.
      Clients before 0.2.1.27 didn't handle NOROUTE correctly, but such
      clients are already deprecated because of security bugs.

  o Minor features (network statistics):
    - Directory mirrors that set "DirReqStatistics 1" write statistics
      about directory requests to disk every 24 hours. As compared to the
      "--enable-geoip-stats" ./configure flag in 0.2.1.x, there are a few
      improvements: 1) stats are written to disk exactly every 24 hours;
      2) estimated shares of v2 and v3 requests are determined as mean
      values, not at the end of a measurement period; 3) unresolved
      requests are listed with country code '??'; 4) directories also
      measure download times.
    - Exit nodes that set "ExitPortStatistics 1" write statistics on the
      number of exit streams and transferred bytes per port to disk every
      24 hours.
    - Relays that set "CellStatistics 1" write statistics on how long
      cells spend in their circuit queues to disk every 24 hours.
    - Entry nodes that set "EntryStatistics 1" write statistics on the
      rough number and origins of connecting clients to disk every 24
      hours.
    - Relays that write any of the above statistics to disk and set
      "ExtraInfoStatistics 1" include the past 24 hours of statistics in
      their extra-info documents. Implements proposal 166.

  o Minor features (GeoIP and statistics):
    - Provide a log message stating which geoip file we're parsing
      instead of just stating that we're parsing the geoip file.
      Implements ticket 2432.
    - Make sure every relay writes a state file at least every 12 hours.
      Previously, a relay could go for weeks without writing its state
      file, and on a crash could lose its bandwidth history, capacity
      estimates, client country statistics, and so on. Addresses bug 3012.
    - Relays report the number of bytes spent on answering directory
      requests in extra-info descriptors similar to {read,write}-history.
      Implements enhancement 1790.
    - Report only the top 10 ports in exit-port stats in order not to
      exceed the maximum extra-info descriptor length of 50 KB. Implements
      task 2196.
    - If writing the state file to disk fails, wait up to an hour before
      retrying again, rather than trying again each second. Fixes bug
      2346; bugfix on Tor 0.1.1.3-alpha.
    - Delay geoip stats collection by bridges for 6 hours, not 2 hours,
      when we switch from being a public relay to a bridge. Otherwise
      there will still be clients that see the relay in their consensus,
      and the stats will end up wrong. Bugfix on 0.2.1.15-rc; fixes
      bug 932.
    - Update to the August 2 2011 Maxmind GeoLite Country database.

  o Minor features (clients):
    - When expiring circuits, use microsecond timers rather than
      one-second timers. This can avoid an unpleasant situation where a
      circuit is launched near the end of one second and expired right
      near the beginning of the next, and prevent fluctuations in circuit
      timeout values.
    - If we've configured EntryNodes and our network goes away and/or all
      our entrynodes get marked down, optimistically retry them all when
      a new socks application request appears. Fixes bug 1882.
    - Always perform router selections using weighted relay bandwidth,
      even if we don't need a high capacity circuit at the time. Non-fast
      circuits now only differ from fast ones in that they can use relays
      not marked with the Fast flag. This "feature" could turn out to
      be a horrible bug; we should investigate more before it goes into
      a stable release.
    - When we run out of directory information such that we can't build
      circuits, but then get enough that we can build circuits, log when
      we actually construct a circuit, so the user has a better chance of
      knowing what's going on. Fixes bug 1362.
    - Log SSL state transitions at debug level during handshake, and
      include SSL states in error messages. This may help debug future
      SSL handshake issues.

  o Minor features (directory authorities):
    - When a router changes IP address or port, authorities now launch
      a new reachability test for it. Implements ticket 1899.
    - Directory authorities now reject relays running any versions of
      Tor between 0.2.1.3-alpha and 0.2.1.18 inclusive; they have
      known bugs that keep RELAY_EARLY cells from working on rendezvous
      circuits. Followup to fix for bug 2081.
    - Directory authorities now reject relays running any version of Tor
      older than 0.2.0.26-rc. That version is the earliest that fetches
      current directory information correctly. Fixes bug 2156.
    - Directory authorities now do an immediate reachability check as soon
      as they hear about a new relay. This change should slightly reduce
      the time between setting up a relay and getting listed as running
      in the consensus. It should also improve the time between setting
      up a bridge and seeing use by bridge users.
    - Directory authorities no longer launch a TLS connection to every
      relay as they startup. Now that we have 2k+ descriptors cached,
      the resulting network hiccup is becoming a burden. Besides,
      authorities already avoid voting about Running for the first half
      hour of their uptime.
    - Directory authorities now log the source of a rejected POSTed v3
      networkstatus vote, so we can track failures better.
    - Backport code from 0.2.3.x that allows directory authorities to
      clean their microdescriptor caches. Needed to resolve bug 2230.

  o Minor features (hidden services):
    - Use computed circuit-build timeouts to decide when to launch
      parallel introduction circuits for hidden services. (Previously,
      we would retry after 15 seconds.)
    - Don't allow v0 hidden service authorities to act as clients.
      Required by fix for bug 3000.
    - Ignore SIGNAL NEWNYM commands on relay-only Tor instances. Required
      by fix for bug 3000.
    - Make hidden services work better in private Tor networks by not
      requiring any uptime to join the hidden service descriptor
      DHT. Implements ticket 2088.
    - Log (at info level) when purging pieces of hidden-service-client
      state because of SIGNAL NEWNYM.

  o Minor features (controller interface):
    - New "GETINFO net/listeners/(type)" controller command to return
      a list of addresses and ports that are bound for listeners for a
      given connection type. This is useful when the user has configured
      "SocksPort auto" and the controller needs to know which port got
      chosen. Resolves another part of ticket 3076.
    - Have the controller interface give a more useful message than
      "Internal Error" in response to failed GETINFO requests.
    - Add a TIMEOUT_RATE keyword to the BUILDTIMEOUT_SET control port
      event, to give information on the current rate of circuit timeouts
      over our stored history.
    - The 'EXTENDCIRCUIT' control port command can now be used with
      a circ id of 0 and no path. This feature will cause Tor to build
      a new 'fast' general purpose circuit using its own path selection
      algorithms.
    - Added a BUILDTIMEOUT_SET controller event to describe changes
      to the circuit build timeout.
    - New controller command "getinfo config-text". It returns the
      contents that Tor would write if you send it a SAVECONF command,
      so the controller can write the file to disk itself.

  o Minor features (controller protocol):
    - Add a new ControlSocketsGroupWritable configuration option: when
      it is turned on, ControlSockets are group-writeable by the default
      group of the current user. Patch by Jérémy Bobbio; implements
      ticket 2972.
    - Tor now refuses to create a ControlSocket in a directory that is
      world-readable (or group-readable if ControlSocketsGroupWritable
      is 0). This is necessary because some operating systems do not
      enforce permissions on an AF_UNIX sockets. Permissions on the
      directory holding the socket, however, seems to work everywhere.
    - Warn when CookieAuthFileGroupReadable is set but CookieAuthFile is
      not. This would lead to a cookie that is still not group readable.
      Closes bug 1843. Suggested by katmagic.
    - Future-proof the controller protocol a bit by ignoring keyword
      arguments we do not recognize.

  o Minor features (more useful logging):
    - Revise most log messages that refer to nodes by nickname to
      instead use the "$key=nickname at address" format. This should be
      more useful, especially since nicknames are less and less likely
      to be unique. Resolves ticket 3045.
    - When an HTTPS proxy reports "403 Forbidden", we now explain
      what it means rather than calling it an unexpected status code.
      Closes bug 2503. Patch from Michael Yakubovich.
    - Rate-limit a warning about failures to download v2 networkstatus
      documents. Resolves part of bug 1352.
    - Rate-limit the "your application is giving Tor only an IP address"
      warning. Addresses bug 2000; bugfix on 0.0.8pre2.
    - Rate-limit "Failed to hand off onionskin" warnings.
    - When logging a rate-limited warning, we now mention how many messages
      got suppressed since the last warning.
    - Make the formerly ugly "2 unknown, 7 missing key, 0 good, 0 bad,
      2 no signature, 4 required" messages about consensus signatures
      easier to read, and make sure they get logged at the same severity
      as the messages explaining which keys are which. Fixes bug 1290.
    - Don't warn when we have a consensus that we can't verify because
      of missing certificates, unless those certificates are ones
      that we have been trying and failing to download. Fixes bug 1145.

  o Minor features (log domains):
    - Add documentation for configuring logging at different severities in
      different log domains. We've had this feature since 0.2.1.1-alpha,
      but for some reason it never made it into the manpage. Fixes
      bug 2215.
    - Make it simpler to specify "All log domains except for A and B".
      Previously you needed to say "[*,~A,~B]". Now you can just say
      "[~A,~B]".
    - Add a "LogMessageDomains 1" option to include the domains of log
      messages along with the messages. Without this, there's no way
      to use log domains without reading the source or doing a lot
      of guessing.
    - Add a new "Handshake" log domain for activities that happen
      during the TLS handshake.

  o Minor features (build process):
    - Make compilation with clang possible when using
      "--enable-gcc-warnings" by removing two warning options that clang
      hasn't implemented yet and by fixing a few warnings. Resolves
      ticket 2696.
    - Detect platforms that brokenly use a signed size_t, and refuse to
      build there. Found and analyzed by doorss and rransom.
    - Fix a bunch of compile warnings revealed by mingw with gcc 4.5.
      Resolves bug 2314.
    - Add support for statically linking zlib by specifying
      "--enable-static-zlib", to go with our support for statically
      linking openssl and libevent. Resolves bug 1358.
    - Instead of adding the svn revision to the Tor version string, report
      the git commit (when we're building from a git checkout).
    - Rename the "log.h" header to "torlog.h" so as to conflict with fewer
      system headers.
    - New --digests command-line switch to output the digests of the
      source files Tor was built with.
    - Generate our manpage and HTML documentation using Asciidoc. This
      change should make it easier to maintain the documentation, and
      produce nicer HTML. The build process fails if asciidoc cannot
      be found and building with asciidoc isn't disabled (via the
      "--disable-asciidoc" argument to ./configure. Skipping the manpage
      speeds up the build considerably.

  o Minor features (options / torrc):
    - Warn when the same option is provided more than once in a torrc
      file, on the command line, or in a single SETCONF statement, and
      the option is one that only accepts a single line. Closes bug 1384.
    - Warn when the user configures two HiddenServiceDir lines that point
      to the same directory. Bugfix on 0.0.6 (the version introducing
      HiddenServiceDir); fixes bug 3289.
    - Add new "perconnbwrate" and "perconnbwburst" consensus params to
      do individual connection-level rate limiting of clients. The torrc
      config options with the same names trump the consensus params, if
      both are present. Replaces the old "bwconnrate" and "bwconnburst"
      consensus params which were broken from 0.2.2.7-alpha through
      0.2.2.14-alpha. Closes bug 1947.
    - New config option "WarnUnsafeSocks 0" disables the warning that
      occurs whenever Tor receives a socks handshake using a version of
      the socks protocol that can only provide an IP address (rather
      than a hostname). Setups that do DNS locally over Tor are fine,
      and we shouldn't spam the logs in that case.
    - New config option "CircuitStreamTimeout" to override our internal
      timeout schedule for how many seconds until we detach a stream from
      a circuit and try a new circuit. If your network is particularly
      slow, you might want to set this to a number like 60.
    - New options for SafeLogging to allow scrubbing only log messages
      generated while acting as a relay. Specify "SafeLogging relay" if
      you want to ensure that only messages known to originate from
      client use of the Tor process will be logged unsafely.
    - Time and memory units in the configuration file can now be set to
      fractional units. For example, "2.5 GB" is now a valid value for
      AccountingMax.
    - Support line continuations in the torrc config file. If a line
      ends with a single backslash character, the newline is ignored, and
      the configuration value is treated as continuing on the next line.
      Resolves bug 1929.

  o Minor features (unit tests):
    - Revise our unit tests to use the "tinytest" framework, so we
      can run tests in their own processes, have smarter setup/teardown
      code, and so on. The unit test code has moved to its own
      subdirectory, and has been split into multiple modules.
    - Add a unit test for cross-platform directory-listing code.
    - Add some forgotten return value checks during unit tests. Found
      by coverity.
    - Use GetTempDir to find the proper temporary directory location on
      Windows when generating temporary files for the unit tests. Patch
      by Gisle Vanem.

  o Minor features (misc):
    - The "torify" script now uses torsocks where available.
    - Make Libevent log messages get delivered to controllers later,
      and not from inside the Libevent log handler. This prevents unsafe
      reentrant Libevent calls while still letting the log messages
      get through.
    - Certain Tor clients (such as those behind check.torproject.org) may
      want to fetch the consensus in an extra early manner. To enable this
      a user may now set FetchDirInfoExtraEarly to 1. This also depends on
      setting FetchDirInfoEarly to 1. Previous behavior will stay the same
      as only certain clients who must have this information sooner should
      set this option.
    - Expand homedirs passed to tor-checkkey. This should silence a
      coverity complaint about passing a user-supplied string into
      open() without checking it.
    - Make sure to disable DirPort if running as a bridge. DirPorts aren't
      used on bridges, and it makes bridge scanning somewhat easier.
    - Create the /var/run/tor directory on startup on OpenSUSE if it is
      not already created. Patch from Andreas Stieger. Fixes bug 2573.

  o Minor bugfixes (relays):
    - When a relay decides that its DNS is too broken for it to serve
      as an exit server, it advertised itself as a non-exit, but
      continued to act as an exit. This could create accidental
      partitioning opportunities for users. Instead, if a relay is
      going to advertise reject *:* as its exit policy, it should
      really act with exit policy "reject *:*". Fixes bug 2366.
      Bugfix on Tor 0.1.2.5-alpha. Bugfix by user "postman" on trac.
    - Publish a router descriptor even if generating an extra-info
      descriptor fails. Previously we would not publish a router
      descriptor without an extra-info descriptor; this can cause fast
      exit relays collecting exit-port statistics to drop from the
      consensus. Bugfix on 0.1.2.9-rc; fixes bug 2195.
    - When we're trying to guess whether we know our IP address as
      a relay, we would log various ways that we failed to guess
      our address, but never log that we ended up guessing it
      successfully. Now add a log line to help confused and anxious
      relay operators. Bugfix on 0.1.2.1-alpha; fixes bug 1534.
    - For bandwidth accounting, calculate our expected bandwidth rate
      based on the time during which we were active and not in
      soft-hibernation during the last interval. Previously, we were
      also considering the time spent in soft-hibernation. If this
      was a long time, we would wind up underestimating our bandwidth
      by a lot, and skewing our wakeup time towards the start of the
      accounting interval. Fixes bug 1789. Bugfix on 0.0.9pre5.
    - Demote a confusing TLS warning that relay operators might get when
      someone tries to talk to their ORPort. It is not the operator's
      fault, nor can they do anything about it. Fixes bug 1364; bugfix
      on 0.2.0.14-alpha.
    - Change "Application request when we're believed to be offline."
      notice to "Application request when we haven't used client
      functionality lately.", to clarify that it's not an error. Bugfix
      on 0.0.9.3; fixes bug 1222.

  o Minor bugfixes (bridges):
    - When a client starts or stops using bridges, never use a circuit
      that was built before the configuration change. This behavior could
      put at risk a user who uses bridges to ensure that her traffic
      only goes to the chosen addresses. Bugfix on 0.2.0.3-alpha; fixes
      bug 3200.
    - Do not reset the bridge descriptor download status every time we
      re-parse our configuration or get a configuration change. Fixes
      bug 3019; bugfix on 0.2.0.3-alpha.
    - Users couldn't configure a regular relay to be their bridge. It
      didn't work because when Tor fetched the bridge descriptor, it found
      that it already had it, and didn't realize that the purpose of the
      descriptor had changed. Now we replace routers with a purpose other
      than bridge with bridge descriptors when fetching them. Bugfix on
      0.1.1.9-alpha. Fixes bug 1776.
    - In the special case where you configure a public exit relay as your
      bridge, Tor would be willing to use that exit relay as the last
      hop in your circuit as well. Now we fail that circuit instead.
      Bugfix on 0.2.0.12-alpha. Fixes bug 2403. Reported by "piebeer".

  o Minor bugfixes (clients):
    - We now ask the other side of a stream (the client or the exit)
      for more data on that stream when the amount of queued data on
      that stream dips low enough. Previously, we wouldn't ask the
      other side for more data until either it sent us more data (which
      it wasn't supposed to do if it had exhausted its window!) or we
      had completely flushed all our queued data. This flow control fix
      should improve throughput. Fixes bug 2756; bugfix on the earliest
      released versions of Tor (svn commit r152).
    - When a client finds that an origin circuit has run out of 16-bit
      stream IDs, we now mark it as unusable for new streams. Previously,
      we would try to close the entire circuit. Bugfix on 0.0.6.
    - Make it explicit that we don't cannibalize one-hop circuits. This
      happens in the wild, but doesn't turn out to be a problem because
      we fortunately don't use those circuits. Many thanks to outofwords
      for the initial analysis and to swissknife who confirmed that
      two-hop circuits are actually created.
    - Resolve an edge case in path weighting that could make us misweight
      our relay selection. Fixes bug 1203; bugfix on 0.0.8rc1.
    - Make the DNSPort option work with libevent 2.x. Don't alter the
      behavior for libevent 1.x. Fixes bug 1143. Found by SwissTorExit.

  o Minor bugfixes (directory authorities):
    - Make directory authorities more accurate at recording when
      relays that have failed several reachability tests became
      unreachable, so we can provide more accuracy at assigning Stable,
      Guard, HSDir, etc flags. Bugfix on 0.2.0.6-alpha. Resolves bug 2716.
    - Directory authorities are now more robust to hops back in time
      when calculating router stability. Previously, if a run of uptime
      or downtime appeared to be negative, the calculation could give
      incorrect results. Bugfix on 0.2.0.6-alpha; noticed when fixing
      bug 1035.
    - Directory authorities will now attempt to download consensuses
      if their own efforts to make a live consensus have failed. This
      change means authorities that restart will fetch a valid
      consensus, and it means authorities that didn't agree with the
      current consensus will still fetch and serve it if it has enough
      signatures. Bugfix on 0.2.0.9-alpha; fixes bug 1300.
    - Never vote for a server as "Running" if we have a descriptor for
      it claiming to be hibernating, and that descriptor was published
      more recently than our last contact with the server. Bugfix on
      0.2.0.3-alpha; fixes bug 911.
    - Directory authorities no longer change their opinion of, or vote on,
      whether a router is Running, unless they have themselves been
      online long enough to have some idea. Bugfix on 0.2.0.6-alpha.
      Fixes bug 1023.

  o Minor bugfixes (hidden services):
    - Log malformed requests for rendezvous descriptors as protocol
      warnings, not warnings. Also, use a more informative log message
      in case someone sees it at log level warning without prior
      info-level messages. Fixes bug 2748; bugfix on 0.2.0.10-alpha.
    - Accept hidden service descriptors if we think we might be a hidden
      service directory, regardless of what our consensus says. This
      helps robustness, since clients and hidden services can sometimes
      have a more up-to-date view of the network consensus than we do,
      and if they think that the directory authorities list us a HSDir,
      we might actually be one. Related to bug 2732; bugfix on
      0.2.0.10-alpha.
    - Correct the warning displayed when a rendezvous descriptor exceeds
      the maximum size. Fixes bug 2750; bugfix on 0.2.1.5-alpha. Found by
      John Brooks.
    - Clients and hidden services now use HSDir-flagged relays for hidden
      service descriptor downloads and uploads even if the relays have no
      DirPort set and the client has disabled TunnelDirConns. This will
      eventually allow us to give the HSDir flag to relays with no
      DirPort. Fixes bug 2722; bugfix on 0.2.1.6-alpha.
    - Only limit the lengths of single HS descriptors, even when multiple
      HS descriptors are published to an HSDir relay in a single POST
      operation. Fixes bug 2948; bugfix on 0.2.1.5-alpha. Found by hsdir.

  o Minor bugfixes (controllers):
    - Allow GETINFO fingerprint to return a fingerprint even when
      we have not yet built a router descriptor. Fixes bug 3577;
      bugfix on 0.2.0.1-alpha.
    - Send a SUCCEEDED stream event to the controller when a reverse
      resolve succeeded. Fixes bug 3536; bugfix on 0.0.8pre1. Issue
      discovered by katmagic.
    - Remove a trailing asterisk from "exit-policy/default" in the
      output of the control port command "GETINFO info/names". Bugfix
      on 0.1.2.5-alpha.
    - Make the SIGNAL DUMP controller command work on FreeBSD. Fixes bug
      2917. Bugfix on 0.1.1.1-alpha.
    - When we restart our relay, we might get a successful connection
      from the outside before we've started our reachability tests,
      triggering a warning: "ORPort found reachable, but I have no
      routerinfo yet. Failing to inform controller of success." This
      bug was harmless unless Tor is running under a controller
      like Vidalia, in which case the controller would never get a
      REACHABILITY_SUCCEEDED status event. Bugfix on 0.1.2.6-alpha;
      fixes bug 1172.
    - When a controller changes TrackHostExits, remove mappings for
      hosts that should no longer have their exits tracked. Bugfix on
      0.1.0.1-rc.
    - When a controller changes VirtualAddrNetwork, remove any mappings
      for hosts that were automapped to the old network. Bugfix on
      0.1.1.19-rc.
    - When a controller changes one of the AutomapHosts* options, remove
      any mappings for hosts that should no longer be automapped. Bugfix
      on 0.2.0.1-alpha.
    - Fix an off-by-one error in calculating some controller command
      argument lengths. Fortunately, this mistake is harmless since
      the controller code does redundant NUL termination too. Found by
      boboper. Bugfix on 0.1.1.1-alpha.
    - Fix a bug in the controller interface where "GETINFO ns/asdaskljkl"
      would return "551 Internal error" rather than "552 Unrecognized key
      ns/asdaskljkl". Bugfix on 0.1.2.3-alpha.
    - Don't spam the controller with events when we have no file
      descriptors available. Bugfix on 0.2.1.5-alpha. (Rate-limiting
      for log messages was already solved from bug 748.)
    - Emit a GUARD DROPPED controller event for a case we missed.
    - Ensure DNS requests launched by "RESOLVE" commands from the
      controller respect the __LeaveStreamsUnattached setconf options. The
      same goes for requests launched via DNSPort or transparent
      proxying. Bugfix on 0.2.0.1-alpha; fixes bug 1525.

  o Minor bugfixes (config options):
    - Tor used to limit HttpProxyAuthenticator values to 48 characters.
      Change the limit to 512 characters by removing base64 newlines.
      Fixes bug 2752. Fix by Michael Yakubovich.
    - Complain if PublishServerDescriptor is given multiple arguments that
      include 0 or 1. This configuration will be rejected in the future.
      Bugfix on 0.2.0.1-alpha; closes bug 1107.
    - Disallow BridgeRelay 1 and ORPort 0 at once in the configuration.
      Bugfix on 0.2.0.13-alpha; closes bug 928.

  o Minor bugfixes (log subsystem fixes):
    - When unable to format an address as a string, report its value
      as "???" rather than reusing the last formatted address. Bugfix
      on 0.2.1.5-alpha.
    - Be more consistent in our treatment of file system paths. "~" should
      get expanded to the user's home directory in the Log config option.
      Fixes bug 2971; bugfix on 0.2.0.1-alpha, which introduced the
      feature for the -f and --DataDirectory options.

  o Minor bugfixes (memory management):
    - Don't stack-allocate the list of supplementary GIDs when we're
      about to log them. Stack-allocating NGROUPS_MAX gid_t elements
      could take up to 256K, which is way too much stack. Found by
      Coverity; CID #450. Bugfix on 0.2.1.7-alpha.
    - Save a couple bytes in memory allocation every time we escape
      certain characters in a string. Patch from Florian Zumbiehl.

  o Minor bugfixes (protocol correctness):
    - When checking for 1024-bit keys, check for 1024 bits, not 128
      bytes. This allows Tor to correctly discard keys of length 1017
      through 1023. Bugfix on 0.0.9pre5.
    - Require that introduction point keys and onion handshake keys
      have a public exponent of 65537. Starts to fix bug 3207; bugfix
      on 0.2.0.10-alpha.
    - Handle SOCKS messages longer than 128 bytes long correctly, rather
      than waiting forever for them to finish. Fixes bug 2330; bugfix
      on 0.2.0.16-alpha. Found by doorss.
    - Never relay a cell for a circuit we have already destroyed.
      Between marking a circuit as closeable and finally closing it,
      it may have been possible for a few queued cells to get relayed,
      even though they would have been immediately dropped by the next
      OR in the circuit. Fixes bug 1184; bugfix on 0.2.0.1-alpha.
    - Never queue a cell for a circuit that's already been marked
      for close.
    - Fix a spec conformance issue: the network-status-version token
      must be the first token in a v3 consensus or vote. Discovered by
      "parakeep". Bugfix on 0.2.0.3-alpha.
    - A networkstatus vote must contain exactly one signature. Spec
      conformance issue. Bugfix on 0.2.0.3-alpha.
    - When asked about a DNS record type we don't support via a
      client DNSPort, reply with NOTIMPL rather than an empty
      reply. Patch by intrigeri. Fixes bug 3369; bugfix on 2.0.1-alpha.
    - Make more fields in the controller protocol case-insensitive, since
      control-spec.txt said they were.

  o Minor bugfixes (log messages):
    - Fix a log message that said "bits" while displaying a value in
      bytes. Found by wanoskarnet. Fixes bug 3318; bugfix on
      0.2.0.1-alpha.
    - Downgrade "no current certificates known for authority" message from
      Notice to Info. Fixes bug 2899; bugfix on 0.2.0.10-alpha.
    - Correctly describe errors that occur when generating a TLS object.
      Previously we would attribute them to a failure while generating a
      TLS context. Patch by Robert Ransom. Bugfix on 0.1.0.4-rc; fixes
      bug 1994.
    - Fix an instance where a Tor directory mirror might accidentally
      log the IP address of a misbehaving Tor client. Bugfix on
      0.1.0.1-rc.
    - Stop logging at severity 'warn' when some other Tor client tries
      to establish a circuit with us using weak DH keys. It's a protocol
      violation, but that doesn't mean ordinary users need to hear about
      it. Fixes the bug part of bug 1114. Bugfix on 0.1.0.13.
    - If your relay can't keep up with the number of incoming create
      cells, it would log one warning per failure into your logs. Limit
      warnings to 1 per minute. Bugfix on 0.0.2pre10; fixes bug 1042.

  o Minor bugfixes (build fixes):
    - Fix warnings from GCC 4.6's "-Wunused-but-set-variable" option.
    - When warning about missing zlib development packages during compile,
      give the correct package names. Bugfix on 0.2.0.1-alpha.
    - Fix warnings that newer versions of autoconf produce during
      ./autogen.sh. These warnings appear to be harmless in our case,
      but they were extremely verbose. Fixes bug 2020.
    - Squash a compile warning on OpenBSD. Reported by Tas; fixes
      bug 1848.

  o Minor bugfixes (portability):
    - Write several files in text mode, on OSes that distinguish text
      mode from binary mode (namely, Windows). These files are:
      'buffer-stats', 'dirreq-stats', and 'entry-stats' on relays
      that collect those statistics; 'client_keys' and 'hostname' for
      hidden services that use authentication; and (in the tor-gencert
      utility) newly generated identity and signing keys. Previously,
      we wouldn't specify text mode or binary mode, leading to an
      assertion failure. Fixes bug 3607. Bugfix on 0.2.1.1-alpha (when
      the DirRecordUsageByCountry option which would have triggered
      the assertion failure was added), although this assertion failure
      would have occurred in tor-gencert on Windows in 0.2.0.1-alpha.
    - Selectively disable deprecation warnings on OS X because Lion
      started deprecating the shipped copy of openssl. Fixes bug 3643.
    - Use a wide type to hold sockets when built for 64-bit Windows.
      Fixes bug 3270.
    - Fix an issue that prevented static linking of libevent on
      some platforms (notably Linux). Fixes bug 2698; bugfix on 0.2.1.23,
      where we introduced the "--with-static-libevent" configure option.
    - Fix a bug with our locking implementation on Windows that couldn't
      correctly detect when a file was already locked. Fixes bug 2504,
      bugfix on 0.2.1.6-alpha.
    - Build correctly on OSX with zlib 1.2.4 and higher with all warnings
      enabled.
    - Fix IPv6-related connect() failures on some platforms (BSD, OS X).
      Bugfix on 0.2.0.3-alpha; fixes first part of bug 2660. Patch by
      "piebeer".

  o Minor bugfixes (code correctness):
    - Always NUL-terminate the sun_path field of a sockaddr_un before
      passing it to the kernel. (Not a security issue: kernels are
      smart enough to reject bad sockaddr_uns.) Found by Coverity;
      CID #428. Bugfix on Tor 0.2.0.3-alpha.
    - Make connection_printf_to_buf()'s behavior sane. Its callers
      expect it to emit a CRLF iff the format string ends with CRLF;
      it actually emitted a CRLF iff (a) the format string ended with
      CRLF or (b) the resulting string was over 1023 characters long or
      (c) the format string did not end with CRLF *and* the resulting
      string was 1021 characters long or longer. Bugfix on 0.1.1.9-alpha;
      fixes part of bug 3407.
    - Make send_control_event_impl()'s behavior sane. Its callers
      expect it to always emit a CRLF at the end of the string; it
      might have emitted extra control characters as well. Bugfix on
      0.1.1.9-alpha; fixes another part of bug 3407.
    - Make crypto_rand_int() check the value of its input correctly.
      Previously, it accepted values up to UINT_MAX, but could return a
      negative number if given a value above INT_MAX+1. Found by George
      Kadianakis. Fixes bug 3306; bugfix on 0.2.2pre14.
    - Fix a potential null-pointer dereference while computing a
      consensus. Bugfix on 0.2.0.3-alpha, found with the help of
      clang's analyzer.
    - If we fail to compute the identity digest of a v3 legacy keypair,
      warn, and don't use a buffer-full of junk instead. Bugfix on
      0.2.1.1-alpha; fixes bug 3106.
    - Resolve an untriggerable issue in smartlist_string_num_isin(),
      where if the function had ever in the future been used to check
      for the presence of a too-large number, it would have given an
      incorrect result. (Fortunately, we only used it for 16-bit
      values.) Fixes bug 3175; bugfix on 0.1.0.1-rc.
    - Be more careful about reporting the correct error from a failed
      connect() system call. Under some circumstances, it was possible to
      look at an incorrect value for errno when sending the end reason.
      Bugfix on 0.1.0.1-rc.
    - Correctly handle an "impossible" overflow cases in connection byte
      counting, where we write or read more than 4GB on an edge connection
      in a single second. Bugfix on 0.1.2.8-beta.
    - Avoid a double mark-for-free warning when failing to attach a
      transparent proxy connection. Bugfix on 0.1.2.1-alpha. Fixes
      bug 2279.
    - Correctly detect failure to allocate an OpenSSL BIO. Fixes bug 2378;
      found by "cypherpunks". This bug was introduced before the first
      Tor release, in svn commit r110.
    - Fix a bug in bandwidth history state parsing that could have been
      triggered if a future version of Tor ever changed the timing
      granularity at which bandwidth history is measured. Bugfix on
      Tor 0.1.1.11-alpha.
    - Add assertions to check for overflow in arguments to
      base32_encode() and base32_decode(); fix a signed-unsigned
      comparison there too. These bugs are not actually reachable in Tor,
      but it's good to prevent future errors too. Found by doorss.
    - Avoid a bogus overlapped memcpy in tor_addr_copy(). Reported by
      "memcpyfail".
    - Set target port in get_interface_address6() correctly. Bugfix
      on 0.1.1.4-alpha and 0.2.0.3-alpha; fixes second part of bug 2660.
    - Fix an impossible-to-actually-trigger buffer overflow in relay
      descriptor generation. Bugfix on 0.1.0.15.
    - Fix numerous small code-flaws found by Coverity Scan Rung 3.

  o Minor bugfixes (code improvements):
    - After we free an internal connection structure, overwrite it
      with a different memory value than we use for overwriting a freed
      internal circuit structure. Should help with debugging. Suggested
      by bug 1055.
    - If OpenSSL fails to make a duplicate of a private or public key, log
      an error message and try to exit cleanly. May help with debugging
      if bug 1209 ever remanifests.
    - Some options used different conventions for uppercasing of acronyms
      when comparing manpage and source. Fix those in favor of the
      manpage, as it makes sense to capitalize acronyms.
    - Take a first step towards making or.h smaller by splitting out
      function definitions for all source files in src/or/. Leave
      structures and defines in or.h for now.
    - Remove a few dead assignments during router parsing. Found by
      coverity.
    - Don't use 1-bit wide signed bit fields. Found by coverity.
    - Avoid signed/unsigned comparisons by making SIZE_T_CEILING unsigned.
      None of the cases where we did this before were wrong, but by making
      this change we avoid warnings. Fixes bug 2475; bugfix on 0.2.1.28.
    - The memarea code now uses a sentinel value at the end of each area
      to make sure nothing writes beyond the end of an area. This might
      help debug some conceivable causes of bug 930.
    - Always treat failure to allocate an RSA key as an unrecoverable
      allocation error.
    - Add some more defensive programming for architectures that can't
      handle unaligned integer accesses. We don't know of any actual bugs
      right now, but that's the best time to fix them. Fixes bug 1943.

  o Minor bugfixes (misc):
    - Fix a rare bug in rend_fn unit tests: we would fail a test when
      a randomly generated port is 0. Diagnosed by Matt Edman. Bugfix
      on 0.2.0.10-alpha; fixes bug 1808.
    - Where available, use Libevent 2.0's periodic timers so that our
      once-per-second cleanup code gets called even more closely to
      once per second than it would otherwise. Fixes bug 943.
    - Ignore OutboundBindAddress when connecting to localhost.
      Connections to localhost need to come _from_ localhost, or else
      local servers (like DNS and outgoing HTTP/SOCKS proxies) will often
      refuse to listen.
    - Update our OpenSSL 0.9.8l fix so that it works with OpenSSL 0.9.8m
      too.
    - If any of the v3 certs we download are unparseable, we should
      actually notice the failure so we don't retry indefinitely. Bugfix
      on 0.2.0.x; reported by "rotator".
    - When Tor fails to parse a descriptor of any kind, dump it to disk.
      Might help diagnosing bug 1051.
    - Make our 'torify' script more portable; if we have only one of
      'torsocks' or 'tsocks' installed, don't complain to the user;
      and explain our warning about tsocks better.
    - Fix some urls in the exit notice file and make it XHTML1.1 strict
      compliant. Based on a patch from Christian Kujau.

  o Documentation changes:
    - Modernize the doxygen configuration file slightly. Fixes bug 2707.
    - Resolve all doxygen warnings except those for missing documentation.
      Fixes bug 2705.
    - Add doxygen documentation for more functions, fields, and types.
    - Convert the HACKING file to asciidoc, and add a few new sections
      to it, explaining how we use Git, how we make changelogs, and
      what should go in a patch.
    - Document the default socks host and port (127.0.0.1:9050) for
      tor-resolve.
    - Removed some unnecessary files from the source distribution. The
      AUTHORS file has now been merged into the people page on the
      website. The roadmaps and design doc can now be found in the
      projects directory in svn.

  o Deprecated and removed features (config):
    - Remove the torrc.complete file. It hasn't been kept up to date
      and users will have better luck checking out the manpage.
    - Remove the HSAuthorityRecordStats option that version 0 hidden
      service authorities could use to track statistics of overall v0
      hidden service usage.
    - Remove the obsolete "NoPublish" option; it has been flagged
      as obsolete and has produced a warning since 0.1.1.18-rc.
    - Caches no longer download and serve v2 networkstatus documents
      unless FetchV2Networkstatus flag is set: these documents haven't
      haven't been used by clients or relays since 0.2.0.x. Resolves
      bug 3022.

  o Deprecated and removed features (controller):
    - The controller no longer accepts the old obsolete "addr-mappings/"
      or "unregistered-servers-" GETINFO values.
    - The EXTENDED_EVENTS and VERBOSE_NAMES controller features are now
      always on; using them is necessary for correct forward-compatible
      controllers.

  o Deprecated and removed features (misc):
    - Hidden services no longer publish version 0 descriptors, and clients
      do not request or use version 0 descriptors. However, the old hidden
      service authorities still accept and serve version 0 descriptors
      when contacted by older hidden services/clients.
    - Remove undocumented option "-F" from tor-resolve: it hasn't done
      anything since 0.2.1.16-rc.
    - Remove everything related to building the expert bundle for OS X.
      It has confused many users, doesn't work right on OS X 10.6,
      and is hard to get rid of once installed. Resolves bug 1274.
    - Remove support for .noconnect style addresses. Nobody was using
      them, and they provided another avenue for detecting Tor users
      via application-level web tricks.
    - When we fixed bug 1038 we had to put in a restriction not to send
      RELAY_EARLY cells on rend circuits. This was necessary as long
      as relays using Tor 0.2.1.3-alpha through 0.2.1.18-alpha were
      active. Now remove this obsolete check. Resolves bug 2081.
    - Remove workaround code to handle directory responses from servers
      that had bug 539 (they would send HTTP status 503 responses _and_
      send a body too). Since only server versions before
      0.2.0.16-alpha/0.1.2.19 were affected, there is no longer reason to
      keep the workaround in place.
    - Remove the old 'fuzzy time' logic. It was supposed to be used for
      handling calculations where we have a known amount of clock skew and
      an allowed amount of unknown skew. But we only used it in three
      places, and we never adjusted the known/unknown skew values. This is
      still something we might want to do someday, but if we do, we'll
      want to do it differently.
    - Remove the "--enable-iphone" option to ./configure. According to
      reports from Marco Bonetti, Tor builds fine without any special
      tweaking on recent iPhone SDK versions.


Changes in version 0.2.1.30 - 2011-02-23
  Tor 0.2.1.30 fixes a variety of less critical bugs. The main other
  change is a slight tweak to Tor's TLS handshake that makes relays
  and bridges that run this new version reachable from Iran again.
  We don't expect this tweak will win the arms race long-term, but it
  buys us time until we roll out a better solution.

  o Major bugfixes:
    - Stop sending a CLOCK_SKEW controller status event whenever
      we fetch directory information from a relay that has a wrong clock.
      Instead, only inform the controller when it's a trusted authority
      that claims our clock is wrong. Bugfix on 0.1.2.6-alpha; fixes
      the rest of bug 1074.
    - Fix a bounds-checking error that could allow an attacker to
      remotely crash a directory authority. Bugfix on 0.2.1.5-alpha.
      Found by "piebeer".
    - If relays set RelayBandwidthBurst but not RelayBandwidthRate,
      Tor would ignore their RelayBandwidthBurst setting,
      potentially using more bandwidth than expected. Bugfix on
      0.2.0.1-alpha. Reported by Paul Wouters. Fixes bug 2470.
    - Ignore and warn if the user mistakenly sets "PublishServerDescriptor
      hidserv" in her torrc. The 'hidserv' argument never controlled
      publication of hidden service descriptors. Bugfix on 0.2.0.1-alpha.

  o Minor features:
    - Adjust our TLS Diffie-Hellman parameters to match those used by
      Apache's mod_ssl.
    - Update to the February 1 2011 Maxmind GeoLite Country database.

  o Minor bugfixes:
    - Check for and reject overly long directory certificates and
      directory tokens before they have a chance to hit any assertions.
      Bugfix on 0.2.1.28. Found by "doorss".
    - Bring the logic that gathers routerinfos and assesses the
      acceptability of circuits into line. This prevents a Tor OP from
      getting locked in a cycle of choosing its local OR as an exit for a
      path (due to a .exit request) and then rejecting the circuit because
      its OR is not listed yet. It also prevents Tor clients from using an
      OR running in the same instance as an exit (due to a .exit request)
      if the OR does not meet the same requirements expected of an OR
      running elsewhere. Fixes bug 1859; bugfix on 0.1.0.1-rc.

  o Packaging changes:
    - Stop shipping the Tor specs files and development proposal documents
      in the tarball. They are now in a separate git repository at
      git://git.torproject.org/torspec.git
    - Do not include Git version tags as though they are SVN tags when
      generating a tarball from inside a repository that has switched
      between branches. Bugfix on 0.2.1.15-rc; fixes bug 2402.


Changes in version 0.2.1.29 - 2011-01-15
  Tor 0.2.1.29 continues our recent code security audit work. The main
  fix resolves a remote heap overflow vulnerability that can allow remote
  code execution. Other fixes address a variety of assert and crash bugs,
  most of which we think are hard to exploit remotely.

  o Major bugfixes (security):
    - Fix a heap overflow bug where an adversary could cause heap
      corruption. This bug probably allows remote code execution
      attacks. Reported by "debuger". Fixes CVE-2011-0427. Bugfix on
      0.1.2.10-rc.
    - Prevent a denial-of-service attack by disallowing any
      zlib-compressed data whose compression factor is implausibly
      high. Fixes part of bug 2324; reported by "doorss".
    - Zero out a few more keys in memory before freeing them. Fixes
      bug 2384 and part of bug 2385. These key instances found by
      "cypherpunks", based on Andrew Case's report about being able
      to find sensitive data in Tor's memory space if you have enough
      permissions. Bugfix on 0.0.2pre9.

  o Major bugfixes (crashes):
    - Prevent calls to Libevent from inside Libevent log handlers.
      This had potential to cause a nasty set of crashes, especially
      if running Libevent with debug logging enabled, and running
      Tor with a controller watching for low-severity log messages.
      Bugfix on 0.1.0.2-rc. Fixes bug 2190.
    - Add a check for SIZE_T_MAX to tor_realloc() to try to avoid
      underflow errors there too. Fixes the other part of bug 2324.
    - Fix a bug where we would assert if we ever had a
      cached-descriptors.new file (or another file read directly into
      memory) of exactly SIZE_T_CEILING bytes. Fixes bug 2326; bugfix
      on 0.2.1.25. Found by doorss.
    - Fix some potential asserts and parsing issues with grossly
      malformed router caches. Fixes bug 2352; bugfix on Tor 0.2.1.27.
      Found by doorss.

  o Minor bugfixes (other):
    - Fix a bug with handling misformed replies to reverse DNS lookup
      requests in DNSPort. Bugfix on Tor 0.2.0.1-alpha. Related to a
      bug reported by doorss.
    - Fix compilation on mingw when a pthreads compatibility library
      has been installed. (We don't want to use it, so we shouldn't
      be including pthread.h.) Fixes bug 2313; bugfix on 0.1.0.1-rc.
    - Fix a bug where we would declare that we had run out of virtual
      addresses when the address space was only half-exhausted. Bugfix
      on 0.1.2.1-alpha.
    - Correctly handle the case where AutomapHostsOnResolve is set but
      no virtual addresses are available. Fixes bug 2328; bugfix on
      0.1.2.1-alpha. Bug found by doorss.
    - Correctly handle wrapping around when we run out of virtual
      address space. Found by cypherpunks; bugfix on 0.2.0.5-alpha.

  o Minor features:
    - Update to the January 1 2011 Maxmind GeoLite Country database.
    - Introduce output size checks on all of our decryption functions.

  o Build changes:
    - Tor does not build packages correctly with Automake 1.6 and earlier;
      added a check to Makefile.am to make sure that we're building with
      Automake 1.7 or later.
    - The 0.2.1.28 tarball was missing src/common/OpenBSD_malloc_Linux.c
      because we built it with a too-old version of automake. Thus that
      release broke ./configure --enable-openbsd-malloc, which is popular
      among really fast exit relays on Linux.


Changes in version 0.2.1.28 - 2010-12-17
  Tor 0.2.1.28 does some code cleanup to reduce the risk of remotely
  exploitable bugs. We also took this opportunity to change the IP address
  for one of our directory authorities, and to update the geoip database
  we ship.

  o Major bugfixes:
    - Fix a remotely exploitable bug that could be used to crash instances
      of Tor remotely by overflowing on the heap. Remote-code execution
      hasn't been confirmed, but can't be ruled out. Everyone should
      upgrade. Bugfix on the 0.1.1 series and later.

  o Directory authority changes:
    - Change IP address and ports for gabelmoo (v3 directory authority).

  o Minor features:
    - Update to the December 1 2010 Maxmind GeoLite Country database.


Changes in version 0.2.1.27 - 2010-11-23
  Yet another OpenSSL security patch broke its compatibility with Tor:
  Tor 0.2.1.27 makes relays work with openssl 0.9.8p and 1.0.0.b. We
  also took this opportunity to fix several crash bugs, integrate a new
  directory authority, and update the bundled GeoIP database.

  o Major bugfixes:
    - Resolve an incompatibility with OpenSSL 0.9.8p and OpenSSL 1.0.0b:
      No longer set the tlsext_host_name extension on server SSL objects;
      but continue to set it on client SSL objects. Our goal in setting
      it was to imitate a browser, not a vhosting server. Fixes bug 2204;
      bugfix on 0.2.1.1-alpha.
    - Do not log messages to the controller while shrinking buffer
      freelists. Doing so would sometimes make the controller connection
      try to allocate a buffer chunk, which would mess up the internals
      of the freelist and cause an assertion failure. Fixes bug 1125;
      fixed by Robert Ransom. Bugfix on 0.2.0.16-alpha.
    - Learn our external IP address when we're a relay or bridge, even if
      we set PublishServerDescriptor to 0. Bugfix on 0.2.0.3-alpha,
      where we introduced bridge relays that don't need to publish to
      be useful. Fixes bug 2050.
    - Do even more to reject (and not just ignore) annotations on
      router descriptors received anywhere but from the cache. Previously
      we would ignore such annotations at first, but cache them to disk
      anyway. Bugfix on 0.2.0.8-alpha. Found by piebeer.
    - When you're using bridges and your network goes away and your
      bridges get marked as down, recover when you attempt a new socks
      connection (if the network is back), rather than waiting up to an
      hour to try fetching new descriptors for your bridges. Bugfix on
      0.2.0.3-alpha; fixes bug 1981.

  o Major features:
    - Move to the November 2010 Maxmind GeoLite country db (rather
      than the June 2009 ip-to-country GeoIP db) for our statistics that
      count how many users relays are seeing from each country. Now we'll
      have more accurate data, especially for many African countries.

  o New directory authorities:
    - Set up maatuska (run by Linus Nordberg) as the eighth v3 directory
      authority.

  o Minor bugfixes:
    - Fix an assertion failure that could occur in directory caches or
      bridge users when using a very short voting interval on a testing
      network. Diagnosed by Robert Hogan. Fixes bug 1141; bugfix on
      0.2.0.8-alpha.
    - Enforce multiplicity rules when parsing annotations. Bugfix on
      0.2.0.8-alpha. Found by piebeer.
    - Allow handshaking OR connections to take a full KeepalivePeriod
      seconds to handshake. Previously, we would close them after
      IDLE_OR_CONN_TIMEOUT (180) seconds, the same timeout as if they
      were open. Bugfix on 0.2.1.26; fixes bug 1840. Thanks to mingw-san
      for analysis help.
    - When building with --enable-gcc-warnings on OpenBSD, disable
      warnings in system headers. This makes --enable-gcc-warnings
      pass on OpenBSD 4.8.

  o Minor features:
    - Exit nodes didn't recognize EHOSTUNREACH as a plausible error code,
      and so sent back END_STREAM_REASON_MISC. Clients now recognize a new
      stream ending reason for this case: END_STREAM_REASON_NOROUTE.
      Servers can start sending this code when enough clients recognize
      it. Bugfix on 0.1.0.1-rc; fixes part of bug 1793.
    - Build correctly on mingw with more recent versions of OpenSSL 0.9.8.
      Patch from mingw-san.

  o Removed files:
    - Remove the old debian/ directory from the main Tor distribution.
      The official Tor-for-debian git repository lives at the URL
      https://git.torproject.org/debian/tor.git
    - Stop shipping the old doc/website/ directory in the tarball. We
      changed the website format in late 2010, and what we shipped in
      0.2.1.26 really wasn't that useful anyway.


Changes in version 0.2.1.26 - 2010-05-02
  Tor 0.2.1.26 addresses the recent connection and memory overload
  problems we've been seeing on relays, especially relays with their
  DirPort open. If your relay has been crashing, or you turned it off
  because it used too many resources, give this release a try.

  This release also fixes yet another instance of broken OpenSSL libraries
  that was causing some relays to drop out of the consensus.

  o Major bugfixes:
    - Teach relays to defend themselves from connection overload. Relays
      now close idle circuits early if it looks like they were intended
      for directory fetches. Relays are also more aggressive about closing
      TLS connections that have no circuits on them. Such circuits are
      unlikely to be re-used, and tens of thousands of them were piling
      up at the fast relays, causing the relays to run out of sockets
      and memory. Bugfix on 0.2.0.22-rc (where clients started tunneling
      their directory fetches over TLS).
    - Fix SSL renegotiation behavior on OpenSSL versions like on Centos
      that claim to be earlier than 0.9.8m, but which have in reality
      backported huge swaths of 0.9.8m or 0.9.8n renegotiation
      behavior. Possible fix for some cases of bug 1346.
    - Directory mirrors were fetching relay descriptors only from v2
      directory authorities, rather than v3 authorities like they should.
      Only 2 v2 authorities remain (compared to 7 v3 authorities), leading
      to a serious bottleneck. Bugfix on 0.2.0.9-alpha. Fixes bug 1324.

  o Minor bugfixes:
    - Finally get rid of the deprecated and now harmful notion of "clique
      mode", where directory authorities maintain TLS connections to
      every other relay.

  o Testsuite fixes:
    - In the util/threads test, no longer free the test_mutex before all
      worker threads have finished. Bugfix on 0.2.1.6-alpha.
    - The master thread could starve the worker threads quite badly on
      certain systems, causing them to run only partially in the allowed
      window. This resulted in test failures. Now the master thread sleeps
      occasionally for a few microseconds while the two worker-threads
      compete for the mutex. Bugfix on 0.2.0.1-alpha.


Changes in version 0.2.1.25 - 2010-03-16
  Tor 0.2.1.25 fixes a regression introduced in 0.2.1.23 that could
  prevent relays from guessing their IP address correctly. It also fixes
  several minor potential security bugs.

  o Major bugfixes:
    - Fix a regression from our patch for bug 1244 that caused relays
      to guess their IP address incorrectly if they didn't set Address
      in their torrc and/or their address fails to resolve. Bugfix on
      0.2.1.23; fixes bug 1269.
    - When freeing a session key, zero it out completely. We only zeroed
      the first ptrsize bytes. Bugfix on 0.0.2pre8. Discovered and
      patched by ekir. Fixes bug 1254.

  o Minor bugfixes:
    - Fix a dereference-then-NULL-check sequence when publishing
      descriptors. Bugfix on 0.2.1.5-alpha. Discovered by ekir; fixes
      bug 1255.
    - Fix another dereference-then-NULL-check sequence. Bugfix on
      0.2.1.14-rc. Discovered by ekir; fixes bug 1256.
    - Make sure we treat potentially not NUL-terminated strings correctly.
      Bugfix on 0.1.1.13-alpha. Discovered by rieo; fixes bug 1257.


Changes in version 0.2.1.24 - 2010-02-21
  Tor 0.2.1.24 makes Tor work again on the latest OS X -- this time
  for sure!

  o Minor bugfixes:
    - Work correctly out-of-the-box with even more vendor-patched versions
      of OpenSSL. In particular, make it so Debian and OS X don't need
      customized patches to run/build.


Changes in version 0.2.1.23 - 2010-02-13
  Tor 0.2.1.23 fixes a huge client-side performance bug, makes Tor work
  again on the latest OS X, and updates the location of a directory
  authority.

  o Major bugfixes (performance):
    - We were selecting our guards uniformly at random, and then weighting
      which of our guards we'd use uniformly at random. This imbalance
      meant that Tor clients were severely limited on throughput (and
      probably latency too) by the first hop in their circuit. Now we
      select guards weighted by currently advertised bandwidth. We also
      automatically discard guards picked using the old algorithm. Fixes
      bug 1217; bugfix on 0.2.1.3-alpha. Found by Mike Perry.

  o Major bugfixes:
    - Make Tor work again on the latest OS X: when deciding whether to
      use strange flags to turn TLS renegotiation on, detect the OpenSSL
      version at run-time, not compile time. We need to do this because
      Apple doesn't update its dev-tools headers when it updates its
      libraries in a security patch.
    - Fix a potential buffer overflow in lookup_last_hid_serv_request()
      that could happen on 32-bit platforms with 64-bit time_t. Also fix
      a memory leak when requesting a hidden service descriptor we've
      requested before. Fixes bug 1242, bugfix on 0.2.0.18-alpha. Found
      by aakova.

  o Minor bugfixes:
    - Refactor resolve_my_address() to not use gethostbyname() anymore.
      Fixes bug 1244; bugfix on 0.0.2pre25. Reported by Mike Mestnik.

  o Minor features:
    - Avoid a mad rush at the beginning of each month when each client
      rotates half of its guards. Instead we spread the rotation out
      throughout the month, but we still avoid leaving a precise timestamp
      in the state file about when we first picked the guard. Improves
      over the behavior introduced in 0.1.2.17.


Changes in version 0.2.1.22 - 2010-01-19
  Tor 0.2.1.22 fixes a critical privacy problem in bridge directory
  authorities -- it would tell you its whole history of bridge descriptors
  if you make the right directory request. This stable update also
  rotates two of the seven v3 directory authority keys and locations.

  o Directory authority changes:
    - Rotate keys (both v3 identity and relay identity) for moria1
      and gabelmoo.

  o Major bugfixes:
    - Stop bridge directory authorities from answering dbg-stability.txt
      directory queries, which would let people fetch a list of all
      bridge identities they track. Bugfix on 0.2.1.6-alpha.


Changes in version 0.2.1.21 - 2009-12-21
  Tor 0.2.1.21 fixes an incompatibility with the most recent OpenSSL
  library. If you use Tor on Linux / Unix and you're getting SSL
  renegotiation errors, upgrading should help. We also recommend an
  upgrade if you're an exit relay.

  o Major bugfixes:
    - Work around a security feature in OpenSSL 0.9.8l that prevents our
      handshake from working unless we explicitly tell OpenSSL that we
      are using SSL renegotiation safely. We are, of course, but OpenSSL
      0.9.8l won't work unless we say we are.
    - Avoid crashing if the client is trying to upload many bytes and the
      circuit gets torn down at the same time, or if the flip side
      happens on the exit relay. Bugfix on 0.2.0.1-alpha; fixes bug 1150.

  o Minor bugfixes:
    - Do not refuse to learn about authority certs and v2 networkstatus
      documents that are older than the latest consensus. This bug might
      have degraded client bootstrapping. Bugfix on 0.2.0.10-alpha.
      Spotted and fixed by xmux.
    - Fix a couple of very-hard-to-trigger memory leaks, and one hard-to-
      trigger platform-specific option misparsing case found by Coverity
      Scan.
    - Fix a compilation warning on Fedora 12 by removing an impossible-to-
      trigger assert. Fixes bug 1173.


Changes in version 0.2.1.20 - 2009-10-15
  Tor 0.2.1.20 fixes a crash bug when you're accessing many hidden
  services at once, prepares for more performance improvements, and
  fixes a bunch of smaller bugs.

  The Windows and OS X bundles also include a more recent Vidalia,
  and switch from Privoxy to Polipo.

  The OS X installers are now drag and drop. It's best to un-install
  Tor/Vidalia and then install this new bundle, rather than upgrade. If
  you want to upgrade, you'll need to update the paths for Tor and Polipo
  in the Vidalia Settings window.

  o Major bugfixes:
    - Send circuit or stream sendme cells when our window has decreased
      by 100 cells, not when it has decreased by 101 cells. Bug uncovered
      by Karsten when testing the "reduce circuit window" performance
      patch. Bugfix on the 54th commit on Tor -- from July 2002,
      before the release of Tor 0.0.0. This is the new winner of the
      oldest-bug prize.
    - Fix a remotely triggerable memory leak when a consensus document
      contains more than one signature from the same voter. Bugfix on
      0.2.0.3-alpha.
    - Avoid segfault in rare cases when finishing an introduction circuit
      as a client and finding out that we don't have an introduction key
      for it. Fixes bug 1073. Reported by Aaron Swartz.

  o Major features:
    - Tor now reads the "circwindow" parameter out of the consensus,
      and uses that value for its circuit package window rather than the
      default of 1000 cells. Begins the implementation of proposal 168.

  o New directory authorities:
    - Set up urras (run by Jacob Appelbaum) as the seventh v3 directory
      authority.
    - Move moria1 and tonga to alternate IP addresses.

  o Minor bugfixes:
    - Fix a signed/unsigned compile warning in 0.2.1.19.
    - Fix possible segmentation fault on directory authorities. Bugfix on
      0.2.1.14-rc.
    - Fix an extremely rare infinite recursion bug that could occur if
      we tried to log a message after shutting down the log subsystem.
      Found by Matt Edman. Bugfix on 0.2.0.16-alpha.
    - Fix an obscure bug where hidden services on 64-bit big-endian
      systems might mis-read the timestamp in v3 introduce cells, and
      refuse to connect back to the client. Discovered by "rotor".
      Bugfix on 0.2.1.6-alpha.
    - We were triggering a CLOCK_SKEW controller status event whenever
      we connect via the v2 connection protocol to any relay that has
      a wrong clock. Instead, we should only inform the controller when
      it's a trusted authority that claims our clock is wrong. Bugfix
      on 0.2.0.20-rc; starts to fix bug 1074. Reported by SwissTorExit.
    - We were telling the controller about CHECKING_REACHABILITY and
      REACHABILITY_FAILED status events whenever we launch a testing
      circuit or notice that one has failed. Instead, only tell the
      controller when we want to inform the user of overall success or
      overall failure. Bugfix on 0.1.2.6-alpha. Fixes bug 1075. Reported
      by SwissTorExit.
    - Don't warn when we're using a circuit that ends with a node
      excluded in ExcludeExitNodes, but the circuit is not used to access
      the outside world. This should help fix bug 1090. Bugfix on
      0.2.1.6-alpha.
    - Work around a small memory leak in some versions of OpenSSL that
      stopped the memory used by the hostname TLS extension from being
      freed.

  o Minor features:
    - Add a "getinfo status/accepted-server-descriptor" controller
      command, which is the recommended way for controllers to learn
      whether our server descriptor has been successfully received by at
      least on directory authority. Un-recommend good-server-descriptor
      getinfo and status events until we have a better design for them.


Changes in version 0.2.1.19 - 2009-07-28
  Tor 0.2.1.19 fixes a major bug with accessing and providing hidden
  services.

  o Major bugfixes:
    - Make accessing hidden services on 0.2.1.x work right again.
      Bugfix on 0.2.1.3-alpha; workaround for bug 1038. Diagnosis and
      part of patch provided by "optimist".

  o Minor features:
    - When a relay/bridge is writing out its identity key fingerprint to
      the "fingerprint" file and to its logs, write it without spaces. Now
      it will look like the fingerprints in our bridges documentation,
      and confuse fewer users.

  o Minor bugfixes:
    - Relays no longer publish a new server descriptor if they change
      their MaxAdvertisedBandwidth config option but it doesn't end up
      changing their advertised bandwidth numbers. Bugfix on 0.2.0.28-rc;
      fixes bug 1026. Patch from Sebastian.
    - Avoid leaking memory every time we get a create cell but we have
      so many already queued that we refuse it. Bugfix on 0.2.0.19-alpha;
      fixes bug 1034. Reported by BarkerJr.


Changes in version 0.2.1.18 - 2009-07-24
  Tor 0.2.1.18 lays the foundations for performance improvements,
  adds status events to help users diagnose bootstrap problems, adds
  optional authentication/authorization for hidden services, fixes a
  variety of potential anonymity problems, and includes a huge pile of
  other features and bug fixes.

  o Major features (clients):
    - Start sending "bootstrap phase" status events to the controller,
      so it can keep the user informed of progress fetching directory
      information and establishing circuits. Also inform the controller
      if we think we're stuck at a particular bootstrap phase. Implements
      proposal 137.
    - Clients replace entry guards that were chosen more than a few months
      ago. This change should significantly improve client performance,
      especially once more people upgrade, since relays that have been
      a guard for a long time are currently overloaded.
    - Network status consensus documents and votes now contain bandwidth
      information for each relay. Clients use the bandwidth values
      in the consensus, rather than the bandwidth values in each
      relay descriptor. This approach opens the door to more accurate
      bandwidth estimates once the directory authorities start doing
      active measurements. Implements part of proposal 141.

  o Major features (relays):
    - Disable and refactor some debugging checks that forced a linear scan
      over the whole server-side DNS cache. These accounted for over 50%
      of CPU time on a relatively busy exit node's gprof profile. Also,
      disable some debugging checks that appeared in exit node profile
      data. Found by Jacob.
    - New DirPortFrontPage option that takes an html file and publishes
      it as "/" on the DirPort. Now relay operators can provide a
      disclaimer without needing to set up a separate webserver. There's
      a sample disclaimer in contrib/tor-exit-notice.html.

  o Major features (hidden services):
    - Make it possible to build hidden services that only certain clients
      are allowed to connect to. This is enforced at several points,
      so that unauthorized clients are unable to send INTRODUCE cells
      to the service, or even (depending on the type of authentication)
      to learn introduction points. This feature raises the bar for
      certain kinds of active attacks against hidden services. Design
      and code by Karsten Loesing. Implements proposal 121.
    - Relays now store and serve v2 hidden service descriptors by default,
      i.e., the new default value for HidServDirectoryV2 is 1. This is
      the last step in proposal 114, which aims to make hidden service
      lookups more reliable.

  o Major features (path selection):
    - ExitNodes and Exclude*Nodes config options now allow you to restrict
      by country code ("{US}") or IP address or address pattern
      ("255.128.0.0/16"). Patch from Robert Hogan. It still needs some
      refinement to decide what config options should take priority if
      you ask to both use a particular node and exclude it.

  o Major features (misc):
    - When building a consensus, do not include routers that are down.
      This cuts down 30% to 40% on consensus size. Implements proposal
      138.
    - New TestingTorNetwork config option to allow adjustment of
      previously constant values that could slow bootstrapping. Implements
      proposal 135. Patch from Karsten.
    - Convert many internal address representations to optionally hold
      IPv6 addresses. Generate and accept IPv6 addresses in many protocol
      elements. Make resolver code handle nameservers located at IPv6
      addresses.
    - More work on making our TLS handshake blend in: modify the list
      of ciphers advertised by OpenSSL in client mode to even more
      closely resemble a common web browser. We cheat a little so that
      we can advertise ciphers that the locally installed OpenSSL doesn't
      know about.
    - Use the TLS1 hostname extension to more closely resemble browser
      behavior.

  o Security fixes (anonymity/entropy):
    - Never use a connection with a mismatched address to extend a
      circuit, unless that connection is canonical. A canonical
      connection is one whose address is authenticated by the router's
      identity key, either in a NETINFO cell or in a router descriptor.
    - Implement most of proposal 110: The first K cells to be sent
      along a circuit are marked as special "early" cells; only K "early"
      cells will be allowed. Once this code is universal, we can block
      certain kinds of denial-of-service attack by requiring that EXTEND
      commands must be sent using an "early" cell.
    - Resume using OpenSSL's RAND_poll() for better (and more portable)
      cross-platform entropy collection again. We used to use it, then
      stopped using it because of a bug that could crash systems that
      called RAND_poll when they had a lot of fds open. It looks like the
      bug got fixed in late 2006. Our new behavior is to call RAND_poll()
      at startup, and to call RAND_poll() when we reseed later only if
      we have a non-buggy OpenSSL version.
    - When the client is choosing entry guards, now it selects at most
      one guard from a given relay family. Otherwise we could end up with
      all of our entry points into the network run by the same operator.
      Suggested by Camilo Viecco. Fix on 0.1.1.11-alpha.
    - Do not use or believe expired v3 authority certificates. Patch
      from Karsten. Bugfix in 0.2.0.x. Fixes bug 851.
    - Drop begin cells to a hidden service if they come from the middle
      of a circuit. Patch from lark.
    - When we erroneously receive two EXTEND cells for the same circuit
      ID on the same connection, drop the second. Patch from lark.
    - Authorities now vote for the Stable flag for any router whose
      weighted MTBF is at least 5 days, regardless of the mean MTBF.
    - Clients now never report any stream end reason except 'MISC'.
      Implements proposal 148.

  o Major bugfixes (crashes):
    - Parse dates and IPv4 addresses in a locale- and libc-independent
      manner, to avoid platform-dependent behavior on malformed input.
    - Fix a crash that occurs on exit nodes when a nameserver request
      timed out. Bugfix on 0.1.2.1-alpha; our CLEAR debugging code had
      been suppressing the bug since 0.1.2.10-alpha. Partial fix for
      bug 929.
    - Do not assume that a stack-allocated character array will be
      64-bit aligned on platforms that demand that uint64_t access is
      aligned. Possible fix for bug 604.
    - Resolve a very rare crash bug that could occur when the user forced
      a nameserver reconfiguration during the middle of a nameserver
      probe. Fixes bug 526. Bugfix on 0.1.2.1-alpha.
    - Avoid a "0 divided by 0" calculation when calculating router uptime
      at directory authorities. Bugfix on 0.2.0.8-alpha.
    - Fix an assertion bug in parsing policy-related options; possible fix
      for bug 811.
    - Rate-limit too-many-sockets messages: when they happen, they happen
      a lot and end up filling up the disk. Resolves bug 748.
    - Fix a race condition that could cause crashes or memory corruption
      when running as a server with a controller listening for log
      messages.
    - Avoid crashing when we have a policy specified in a DirPolicy or
      SocksPolicy or ReachableAddresses option with ports set on it,
      and we re-load the policy. May fix bug 996.
    - Fix an assertion failure on 64-bit platforms when we allocated
      memory right up to the end of a memarea, then realigned the memory
      one step beyond the end. Fixes a possible cause of bug 930.
    - Protect the count of open sockets with a mutex, so we can't
      corrupt it when two threads are closing or opening sockets at once.
      Fix for bug 939. Bugfix on 0.2.0.1-alpha.

  o Major bugfixes (clients):
    - Discard router descriptors as we load them if they are more than
      five days old. Otherwise if Tor is off for a long time and then
      starts with cached descriptors, it will try to use the onion keys
      in those obsolete descriptors when building circuits. Fixes bug 887.
    - When we choose to abandon a new entry guard because we think our
      older ones might be better, close any circuits pending on that
      new entry guard connection. This fix should make us recover much
      faster when our network is down and then comes back. Bugfix on
      0.1.2.8-beta; found by lodger.
    - When Tor clients restart after 1-5 days, they discard all their
      cached descriptors as too old, but they still use the cached
      consensus document. This approach is good for robustness, but
      bad for performance: since they don't know any bandwidths, they
      end up choosing at random rather than weighting their choice by
      speed. Fixed by the above feature of putting bandwidths in the
      consensus.

  o Major bugfixes (relays):
    - Relays were falling out of the networkstatus consensus for
      part of a day if they changed their local config but the
      authorities discarded their new descriptor as "not sufficiently
      different". Now directory authorities accept a descriptor as changed
      if BandwidthRate or BandwidthBurst changed. Partial fix for bug 962;
      patch by Sebastian.
    - Ensure that two circuits can never exist on the same connection
      with the same circuit ID, even if one is marked for close. This
      is conceivably a bugfix for bug 779; fixes a bug on 0.1.0.4-rc.
    - Directory authorities were neglecting to mark relays down in their
      internal histories if the relays fall off the routerlist without
      ever being found unreachable. So there were relays in the histories
      that haven't been seen for eight months, and are listed as being
      up for eight months. This wreaked havoc on the "median wfu" and
      "median mtbf" calculations, in turn making Guard and Stable flags
      wrong, hurting network performance. Fixes bugs 696 and 969. Bugfix
      on 0.2.0.6-alpha.

  o Major bugfixes (hidden services):
    - When establishing a hidden service, introduction points that
      originate from cannibalized circuits were completely ignored
      and not included in rendezvous service descriptors. This might
      have been another reason for delay in making a hidden service
      available. Bugfix from long ago (0.0.9.x?)

  o Major bugfixes (memory and resource management):
    - Fixed some memory leaks -- some quite frequent, some almost
      impossible to trigger -- based on results from Coverity.
    - Speed up parsing and cut down on memory fragmentation by using
      stack-style allocations for parsing directory objects. Previously,
      this accounted for over 40% of allocations from within Tor's code
      on a typical directory cache.
    - Use a Bloom filter rather than a digest-based set to track which
      descriptors we need to keep around when we're cleaning out old
      router descriptors. This speeds up the computation significantly,
      and may reduce fragmentation.

  o New/changed config options:
    - Now NodeFamily and MyFamily config options allow spaces in
      identity fingerprints, so it's easier to paste them in.
      Suggested by Lucky Green.
    - Allow ports 465 and 587 in the default exit policy again. We had
      rejected them in 0.1.0.15, because back in 2005 they were commonly
      misconfigured and ended up as spam targets. We hear they are better
      locked down these days.
    - Make TrackHostExit mappings expire a while after their last use, not
      after their creation. Patch from Robert Hogan.
    - Add an ExcludeExitNodes option so users can list a set of nodes
      that should be be excluded from the exit node position, but
      allowed elsewhere. Implements proposal 151.
    - New --hush command-line option similar to --quiet. While --quiet
      disables all logging to the console on startup, --hush limits the
      output to messages of warning and error severity.
    - New configure/torrc options (--enable-geoip-stats,
      DirRecordUsageByCountry) to record how many IPs we've served
      directory info to in each country code, how many status documents
      total we've sent to each country code, and what share of the total
      directory requests we should expect to see.
    - Make outbound DNS packets respect the OutboundBindAddress setting.
      Fixes the bug part of bug 798. Bugfix on 0.1.2.2-alpha.
    - Allow separate log levels to be configured for different logging
      domains. For example, this allows one to log all notices, warnings,
      or errors, plus all memory management messages of level debug or
      higher, with: Log [MM] debug-err [*] notice-err file /var/log/tor.
    - Update to the "June 3 2009" ip-to-country file.

  o Minor features (relays):
    - Raise the minimum rate limiting to be a relay from 20000 bytes
      to 20480 bytes (aka 20KB/s), to match our documentation. Also
      update directory authorities so they always assign the Fast flag
      to relays with 20KB/s of capacity. Now people running relays won't
      suddenly find themselves not seeing any use, if the network gets
      faster on average.
    - If we're a relay and we change our IP address, be more verbose
      about the reason that made us change. Should help track down
      further bugs for relays on dynamic IP addresses.
    - Exit servers can now answer resolve requests for ip6.arpa addresses.
    - Implement most of Proposal 152: allow specialized servers to permit
      single-hop circuits, and clients to use those servers to build
      single-hop circuits when using a specialized controller. Patch
      from Josh Albrecht. Resolves feature request 768.
    - When relays do their initial bandwidth measurement, don't limit
      to just our entry guards for the test circuits. Otherwise we tend
      to have multiple test circuits going through a single entry guard,
      which makes our bandwidth test less accurate. Fixes part of bug 654;
      patch contributed by Josh Albrecht.

  o Minor features (directory authorities):
    - Try not to open more than one descriptor-downloading connection
      to an authority at once. This should reduce load on directory
      authorities. Fixes bug 366.
    - Add cross-certification to newly generated certificates, so that
      a signing key is enough information to look up a certificate. Start
      serving certificates by <identity digest, signing key digest>
      pairs. Implements proposal 157.
    - When a directory authority downloads a descriptor that it then
      immediately rejects, do not retry downloading it right away. Should
      save some bandwidth on authorities. Fix for bug 888. Patch by
      Sebastian Hahn.
    - Directory authorities now serve a /tor/dbg-stability.txt URL to
      help debug WFU and MTBF calculations.
    - In directory authorities' approved-routers files, allow
      fingerprints with or without space.

  o Minor features (directory mirrors):
    - When a download gets us zero good descriptors, do not notify
      Tor that new directory information has arrived.
    - Servers support a new URL scheme for consensus downloads that
      allows the client to specify which authorities are trusted.
      The server then only sends the consensus if the client will trust
      it. Otherwise a 404 error is sent back. Clients use this
      new scheme when the server supports it (meaning it's running
      0.2.1.1-alpha or later). Implements proposal 134.

  o Minor features (bridges):
    - If the bridge config line doesn't specify a port, assume 443.
      This makes bridge lines a bit smaller and easier for users to
      understand.
    - If we're using bridges and our network goes away, be more willing
      to forgive our bridges and try again when we get an application
      request.

  o Minor features (hidden services):
    - When the client launches an introduction circuit, retry with a
      new circuit after 30 seconds rather than 60 seconds.
    - Launch a second client-side introduction circuit in parallel
      after a delay of 15 seconds (based on work by Christian Wilms).
    - Hidden services start out building five intro circuits rather
      than three, and when the first three finish they publish a service
      descriptor using those. Now we publish our service descriptor much
      faster after restart.
    - Drop the requirement to have an open dir port for storing and
      serving v2 hidden service descriptors.

  o Minor features (build and packaging):
    - On Linux, use the prctl call to re-enable core dumps when the User
      option is set.
    - Try to make sure that the version of Libevent we're running with
      is binary-compatible with the one we built with. May address bug
      897 and others.
    - Add a new --enable-local-appdata configuration switch to change
      the default location of the datadir on win32 from APPDATA to
      LOCAL_APPDATA. In the future, we should migrate to LOCAL_APPDATA
      entirely. Patch from coderman.
    - Build correctly against versions of OpenSSL 0.9.8 or later that
      are built without support for deprecated functions.
    - On platforms with a maximum syslog string length, truncate syslog
      messages to that length ourselves, rather than relying on the
      system to do it for us.
    - Automatically detect MacOSX versions earlier than 10.4.0, and
      disable kqueue from inside Tor when running with these versions.
      We previously did this from the startup script, but that was no
      help to people who didn't use the startup script. Resolves bug 863.
    - Build correctly when configured to build outside the main source
      path. Patch from Michael Gold.
    - Disable GCC's strict alias optimization by default, to avoid the
      likelihood of its introducing subtle bugs whenever our code violates
      the letter of C99's alias rules.
    - Change the contrib/tor.logrotate script so it makes the new
      logs as "_tor:_tor" rather than the default, which is generally
      "root:wheel". Fixes bug 676, reported by Serge Koksharov.
    - Change our header file guard macros to be less likely to conflict
      with system headers. Adam Langley noticed that we were conflicting
      with log.h on Android.
    - Add a couple of extra warnings to --enable-gcc-warnings for GCC 4.3,
      and stop using a warning that had become unfixably verbose under
      GCC 4.3.
    - Use a lockfile to make sure that two Tor processes are not
      simultaneously running with the same datadir.
    - Allow OpenSSL to use dynamic locks if it wants.
    - Add LIBS=-lrt to Makefile.am so the Tor RPMs use a static libevent.

  o Minor features (controllers):
    - When generating circuit events with verbose nicknames for
      controllers, try harder to look up nicknames for routers on a
      circuit. (Previously, we would look in the router descriptors we had
      for nicknames, but not in the consensus.) Partial fix for bug 941.
    - New controller event NEWCONSENSUS that lists the networkstatus
      lines for every recommended relay. Now controllers like Torflow
      can keep up-to-date on which relays they should be using.
    - New controller event "clients_seen" to report a geoip-based summary
      of which countries we've seen clients from recently. Now controllers
      like Vidalia can show bridge operators that they're actually making
      a difference.
    - Add a 'getinfo status/clients-seen' controller command, in case
      controllers want to hear clients_seen events but connect late.
    - New CONSENSUS_ARRIVED event to note when a new consensus has
      been fetched and validated.
    - Add an internal-use-only __ReloadTorrcOnSIGHUP option for
      controllers to prevent SIGHUP from reloading the configuration.
      Fixes bug 856.
    - Return circuit purposes in response to GETINFO circuit-status.
      Fixes bug 858.
    - Serve the latest v3 networkstatus consensus via the control
      port. Use "getinfo dir/status-vote/current/consensus" to fetch it.
    - Add a "GETINFO /status/bootstrap-phase" controller option, so the
      controller can query our current bootstrap state in case it attaches
      partway through and wants to catch up.
    - Provide circuit purposes along with circuit events to the controller.

  o Minor features (tools):
    - Do not have tor-resolve automatically refuse all .onion addresses;
      if AutomapHostsOnResolve is set in your torrc, this will work fine.
    - Add a -p option to tor-resolve for specifying the SOCKS port: some
      people find host:port too confusing.
    - Print the SOCKS5 error message string as well as the error code
      when a tor-resolve request fails. Patch from Jacob.

  o Minor bugfixes (memory and resource management):
    - Clients no longer cache certificates for authorities they do not
      recognize. Bugfix on 0.2.0.9-alpha.
    - Do not use C's stdio library for writing to log files. This will
      improve logging performance by a minute amount, and will stop
      leaking fds when our disk is full. Fixes bug 861.
    - Stop erroneous use of O_APPEND in cases where we did not in fact
      want to re-seek to the end of a file before every last write().
    - Fix a small alignment and memory-wasting bug on buffer chunks.
      Spotted by rovv.
    - Add a malloc_good_size implementation to OpenBSD_malloc_linux.c,
      to avoid unused RAM in buffer chunks and memory pools.
    - Reduce the default smartlist size from 32 to 16; it turns out that
      most smartlists hold around 8-12 elements tops.
    - Make dumpstats() log the fullness and size of openssl-internal
      buffers.
    - If the user has applied the experimental SSL_MODE_RELEASE_BUFFERS
      patch to their OpenSSL, turn it on to save memory on servers. This
      patch will (with any luck) get included in a mainline distribution
      before too long.
    - Fix a memory leak when v3 directory authorities load their keys
      and cert from disk. Bugfix on 0.2.0.1-alpha.
    - Stop using malloc_usable_size() to use more area than we had
      actually allocated: it was safe, but made valgrind really unhappy.
    - Make the assert_circuit_ok() function work correctly on circuits that
      have already been marked for close.
    - Fix uninitialized size field for memory area allocation: may improve
      memory performance during directory parsing.

  o Minor bugfixes (clients):
    - Stop reloading the router list from disk for no reason when we
      run out of reachable directory mirrors. Once upon a time reloading
      it would set the 'is_running' flag back to 1 for them. It hasn't
      done that for a long time.
    - When we had picked an exit node for a connection, but marked it as
      "optional", and it turned out we had no onion key for the exit,
      stop wanting that exit and try again. This situation may not
      be possible now, but will probably become feasible with proposal
      158. Spotted by rovv. Fixes another case of bug 752.
    - Fix a bug in address parsing that was preventing bridges or hidden
      service targets from being at IPv6 addresses.
    - Do not remove routers as too old if we do not have any consensus
      document. Bugfix on 0.2.0.7-alpha.
    - When an exit relay resolves a stream address to a local IP address,
      do not just keep retrying that same exit relay over and
      over. Instead, just close the stream. Addresses bug 872. Bugfix
      on 0.2.0.32. Patch from rovv.
    - Made Tor a little less aggressive about deleting expired
      certificates. Partial fix for bug 854.
    - Treat duplicate certificate fetches as failures, so that we do
      not try to re-fetch an expired certificate over and over and over.
    - Do not say we're fetching a certificate when we'll in fact skip it
      because of a pending download.
    - If we have correct permissions on $datadir, we complain to stdout
      and fail to start. But dangerous permissions on
      $datadir/cached-status/ would cause us to open a log and complain
      there. Now complain to stdout and fail to start in both cases. Fixes
      bug 820, reported by seeess.

  o Minor bugfixes (bridges):
    - When we made bridge authorities stop serving bridge descriptors over
      unencrypted links, we also broke DirPort reachability testing for
      bridges. So bridges with a non-zero DirPort were printing spurious
      warns to their logs. Bugfix on 0.2.0.16-alpha. Fixes bug 709.
    - Don't allow a bridge to publish its router descriptor to a
      non-bridge directory authority. Fixes part of bug 932.
    - When we change to or from being a bridge, reset our counts of
      client usage by country. Fixes bug 932.

  o Minor bugfixes (relays):
    - Log correct error messages for DNS-related network errors on
      Windows.
    - Actually return -1 in the error case for read_bandwidth_usage().
      Harmless bug, since we currently don't care about the return value
      anywhere. Bugfix on 0.2.0.9-alpha.
    - Provide a more useful log message if bug 977 (related to buffer
      freelists) ever reappears, and do not crash right away.
    - We were already rejecting relay begin cells with destination port
      of 0. Now also reject extend cells with destination port or address
      of 0. Suggested by lark.
    - When we can't transmit a DNS request due to a network error, retry
      it after a while, and eventually transmit a failing response to
      the RESOLVED cell. Bugfix on 0.1.2.5-alpha.
    - Solve a bug that kept hardware crypto acceleration from getting
      enabled when accounting was turned on. Fixes bug 907. Bugfix on
      0.0.9pre6.
    - When a canonical connection appears later in our internal list
      than a noncanonical one for a given OR ID, always use the
      canonical one. Bugfix on 0.2.0.12-alpha. Fixes bug 805.
      Spotted by rovv.
    - Avoid some nasty corner cases in the logic for marking connections
      as too old or obsolete or noncanonical for circuits. Partial
      bugfix on bug 891.
    - Fix another interesting corner-case of bug 891 spotted by rovv:
      Previously, if two hosts had different amounts of clock drift, and
      one of them created a new connection with just the wrong timing,
      the other might decide to deprecate the new connection erroneously.
      Bugfix on 0.1.1.13-alpha.
    - If one win32 nameserver fails to get added, continue adding the
      rest, and don't automatically fail.
    - Fix a bug where an unreachable relay would establish enough
      reachability testing circuits to do a bandwidth test -- if
      we already have a connection to the middle hop of the testing
      circuit, then it could establish the last hop by using the existing
      connection. Bugfix on 0.1.2.2-alpha, exposed when we made testing
      circuits no longer use entry guards in 0.2.1.3-alpha.

  o Minor bugfixes (directory authorities):
    - Limit uploaded directory documents to be 16M rather than 500K.
      The directory authorities were refusing v3 consensus votes from
      other authorities, since the votes are now 504K. Fixes bug 959;
      bugfix on 0.0.2pre17 (where we raised it from 50K to 500K ;).
    - Directory authorities should never send a 503 "busy" response to
      requests for votes or keys. Bugfix on 0.2.0.8-alpha; exposed by
      bug 959.
    - Fix code so authorities _actually_ send back X-Descriptor-Not-New
      headers. Bugfix on 0.2.0.10-alpha.

  o Minor bugfixes (hidden services):
    - When we can't find an intro key for a v2 hidden service descriptor,
      fall back to the v0 hidden service descriptor and log a bug message.
      Workaround for bug 1024.
    - In very rare situations new hidden service descriptors were
      published earlier than 30 seconds after the last change to the
      service. (We currently think that a hidden service descriptor
      that's been stable for 30 seconds is worth publishing.)
    - If a hidden service sends us an END cell, do not consider
      retrying the connection; just close it. Patch from rovv.
    - If we are not using BEGIN_DIR cells, don't attempt to contact hidden
      service directories if they have no advertised dir port. Bugfix
      on 0.2.0.10-alpha.

  o Minor bugfixes (tools):
    - In the torify(1) manpage, mention that tsocks will leak your
      DNS requests.

  o Minor bugfixes (controllers):
    - If the controller claimed responsibility for a stream, but that
      stream never finished making its connection, it would live
      forever in circuit_wait state. Now we close it after SocksTimeout
      seconds. Bugfix on 0.1.2.7-alpha; reported by Mike Perry.
    - Make DNS resolved controller events into "CLOSED", not
      "FAILED". Bugfix on 0.1.2.5-alpha. Fix by Robert Hogan. Resolves
      bug 807.
    - The control port would close the connection before flushing long
      replies, such as the network consensus, if a QUIT command was issued
      before the reply had completed. Now, the control port flushes all
      pending replies before closing the connection. Also fix a spurious
      warning when a QUIT command is issued after a malformed or rejected
      AUTHENTICATE command, but before the connection was closed. Patch
      by Marcus Griep. Fixes bugs 1015 and 1016.
    - Fix a bug that made stream bandwidth get misreported to the
      controller.

  o Deprecated and removed features:
    - The old "tor --version --version" command, which would print out
      the subversion "Id" of most of the source files, is now removed. It
      turned out to be less useful than we'd expected, and harder to
      maintain.
    - RedirectExits has been removed. It was deprecated since
      0.2.0.3-alpha.
    - Finally remove deprecated "EXTENDED_FORMAT" controller feature. It
      has been called EXTENDED_EVENTS since 0.1.2.4-alpha.
    - Cell pools are now always enabled; --disable-cell-pools is ignored.
    - Directory mirrors no longer fetch the v1 directory or
      running-routers files. They are obsolete, and nobody asks for them
      anymore. This is the first step to making v1 authorities obsolete.
    - Take out the TestVia config option, since it was a workaround for
      a bug that was fixed in Tor 0.1.1.21.
    - Mark RendNodes, RendExcludeNodes, HiddenServiceNodes, and
      HiddenServiceExcludeNodes as obsolete: they never worked properly,
      and nobody seems to be using them. Fixes bug 754. Bugfix on
      0.1.0.1-rc. Patch from Christian Wilms.
    - Remove all backward-compatibility code for relays running
      versions of Tor so old that they no longer work at all on the
      Tor network.

  o Code simplifications and refactoring:
    - Tool-assisted documentation cleanup. Nearly every function or
      static variable in Tor should have its own documentation now.
    - Rename the confusing or_is_obsolete field to the more appropriate
      is_bad_for_new_circs, and move it to or_connection_t where it
      belongs.
    - Move edge-only flags from connection_t to edge_connection_t: not
      only is this better coding, but on machines of plausible alignment,
      it should save 4-8 bytes per connection_t. "Every little bit helps."
    - Rename ServerDNSAllowBrokenResolvConf to ServerDNSAllowBrokenConfig
      for consistency; keep old option working for backward compatibility.
    - Simplify the code for finding connections to use for a circuit.
    - Revise the connection_new functions so that a more typesafe variant
      exists. This will work better with Coverity, and let us find any
      actual mistakes we're making here.
    - Refactor unit testing logic so that dmalloc can be used sensibly
      with unit tests to check for memory leaks.
    - Move all hidden-service related fields from connection and circuit
      structure to substructures: this way they won't eat so much memory.
    - Squeeze 2-5% out of client performance (according to oprofile) by
      improving the implementation of some policy-manipulation functions.
    - Change the implementation of ExcludeNodes and ExcludeExitNodes to
      be more efficient. Formerly it was quadratic in the number of
      servers; now it should be linear. Fixes bug 509.
    - Save 16-22 bytes per open circuit by moving the n_addr, n_port,
      and n_conn_id_digest fields into a separate structure that's
      only needed when the circuit has not yet attached to an n_conn.
    - Optimize out calls to time(NULL) that occur for every IO operation,
      or for every cell. On systems like Windows where time() is a
      slow syscall, this fix will be slightly helpful.


Changes in version 0.2.0.35 - 2009-06-24
  o Security fix:
    - Avoid crashing in the presence of certain malformed descriptors.
      Found by lark, and by automated fuzzing.
    - Fix an edge case where a malicious exit relay could convince a
      controller that the client's DNS question resolves to an internal IP
      address. Bug found and fixed by "optimist"; bugfix on 0.1.2.8-beta.

  o Major bugfixes:
    - Finally fix the bug where dynamic-IP relays disappear when their
      IP address changes: directory mirrors were mistakenly telling
      them their old address if they asked via begin_dir, so they
      never got an accurate answer about their new address, so they
      just vanished after a day. For belt-and-suspenders, relays that
      don't set Address in their config now avoid using begin_dir for
      all direct connections. Should fix bugs 827, 883, and 900.
    - Fix a timing-dependent, allocator-dependent, DNS-related crash bug
      that would occur on some exit nodes when DNS failures and timeouts
      occurred in certain patterns. Fix for bug 957.

  o Minor bugfixes:
    - When starting with a cache over a few days old, do not leak
      memory for the obsolete router descriptors in it. Bugfix on
      0.2.0.33; fixes bug 672.
    - Hidden service clients didn't use a cached service descriptor that
      was older than 15 minutes, but wouldn't fetch a new one either,
      because there was already one in the cache. Now, fetch a v2
      descriptor unless the same descriptor was added to the cache within
      the last 15 minutes. Fixes bug 997; reported by Marcus Griep.


Changes in version 0.2.0.34 - 2009-02-08
  Tor 0.2.0.34 features several more security-related fixes. You should
  upgrade, especially if you run an exit relay (remote crash) or a
  directory authority (remote infinite loop), or you're on an older
  (pre-XP) or not-recently-patched Windows (remote exploit).

  This release marks end-of-life for Tor 0.1.2.x. Those Tor versions
  have many known flaws, and nobody should be using them. You should
  upgrade. If you're using a Linux or BSD and its packages are obsolete,
  stop using those packages and upgrade anyway.

  o Security fixes:
    - Fix an infinite-loop bug on handling corrupt votes under certain
      circumstances. Bugfix on 0.2.0.8-alpha.
    - Fix a temporary DoS vulnerability that could be performed by
      a directory mirror. Bugfix on 0.2.0.9-alpha; reported by lark.
    - Avoid a potential crash on exit nodes when processing malformed
      input. Remote DoS opportunity. Bugfix on 0.2.0.33.
    - Do not accept incomplete ipv4 addresses (like 192.168.0) as valid.
      Spec conformance issue. Bugfix on Tor 0.0.2pre27.

  o Minor bugfixes:
    - Fix compilation on systems where time_t is a 64-bit integer.
      Patch from Matthias Drochner.
    - Don't consider expiring already-closed client connections. Fixes
      bug 893. Bugfix on 0.0.2pre20.


Changes in version 0.2.0.33 - 2009-01-21
  Tor 0.2.0.33 fixes a variety of bugs that were making relays less
  useful to users. It also finally fixes a bug where a relay or client
  that's been off for many days would take a long time to bootstrap.

  This update also fixes an important security-related bug reported by
  Ilja van Sprundel. You should upgrade. (We'll send out more details
  about the bug once people have had some time to upgrade.)

  o Security fixes:
    - Fix a heap-corruption bug that may be remotely triggerable on
      some platforms. Reported by Ilja van Sprundel.

  o Major bugfixes:
    - When a stream at an exit relay is in state "resolving" or
      "connecting" and it receives an "end" relay cell, the exit relay
      would silently ignore the end cell and not close the stream. If
      the client never closes the circuit, then the exit relay never
      closes the TCP connection. Bug introduced in Tor 0.1.2.1-alpha;
      reported by "wood".
    - When sending CREATED cells back for a given circuit, use a 64-bit
      connection ID to find the right connection, rather than an addr:port
      combination. Now that we can have multiple OR connections between
      the same ORs, it is no longer possible to use addr:port to uniquely
      identify a connection.
    - Bridge relays that had DirPort set to 0 would stop fetching
      descriptors shortly after startup, and then briefly resume
      after a new bandwidth test and/or after publishing a new bridge
      descriptor. Bridge users that try to bootstrap from them would
      get a recent networkstatus but would get descriptors from up to
      18 hours earlier, meaning most of the descriptors were obsolete
      already. Reported by Tas; bugfix on 0.2.0.13-alpha.
    - Prevent bridge relays from serving their 'extrainfo' document
      to anybody who asks, now that extrainfo docs include potentially
      sensitive aggregated client geoip summaries. Bugfix on
      0.2.0.13-alpha.
    - If the cached networkstatus consensus is more than five days old,
      discard it rather than trying to use it. In theory it could be
      useful because it lists alternate directory mirrors, but in practice
      it just means we spend many minutes trying directory mirrors that
      are long gone from the network. Also discard router descriptors as
      we load them if they are more than five days old, since the onion
      key is probably wrong by now. Bugfix on 0.2.0.x. Fixes bug 887.

  o Minor bugfixes:
    - Do not mark smartlist_bsearch_idx() function as ATTR_PURE. This bug
      could make gcc generate non-functional binary search code. Bugfix
      on 0.2.0.10-alpha.
    - Build correctly on platforms without socklen_t.
    - Compile without warnings on solaris.
    - Avoid potential crash on internal error during signature collection.
      Fixes bug 864. Patch from rovv.
    - Correct handling of possible malformed authority signing key
      certificates with internal signature types. Fixes bug 880.
      Bugfix on 0.2.0.3-alpha.
    - Fix a hard-to-trigger resource leak when logging credential status.
      CID 349.
    - When we can't initialize DNS because the network is down, do not
      automatically stop Tor from starting. Instead, we retry failed
      dns_init() every 10 minutes, and change the exit policy to reject
      *:* until one succeeds. Fixes bug 691.
    - Use 64 bits instead of 32 bits for connection identifiers used with
      the controller protocol, to greatly reduce risk of identifier reuse.
    - When we're choosing an exit node for a circuit, and we have
      no pending streams, choose a good general exit rather than one that
      supports "all the pending streams". Bugfix on 0.1.1.x. Fix by rovv.
    - Fix another case of assuming, when a specific exit is requested,
      that we know more than the user about what hosts it allows.
      Fixes one case of bug 752. Patch from rovv.
    - Clip the MaxCircuitDirtiness config option to a minimum of 10
      seconds. Warn the user if lower values are given in the
      configuration. Bugfix on 0.1.0.1-rc. Patch by Sebastian.
    - Clip the CircuitBuildTimeout to a minimum of 30 seconds. Warn the
      user if lower values are given in the configuration. Bugfix on
      0.1.1.17-rc. Patch by Sebastian.
    - Fix a memory leak when we decline to add a v2 rendezvous descriptor to
      the cache because we already had a v0 descriptor with the same ID.
      Bugfix on 0.2.0.18-alpha.
    - Fix a race condition when freeing keys shared between main thread
      and CPU workers that could result in a memory leak. Bugfix on
      0.1.0.1-rc. Fixes bug 889.
    - Send a valid END cell back when a client tries to connect to a
      nonexistent hidden service port. Bugfix on 0.1.2.15. Fixes bug
      840. Patch from rovv.
    - Check which hops rendezvous stream cells are associated with to
      prevent possible guess-the-streamid injection attacks from
      intermediate hops. Fixes another case of bug 446. Based on patch
      from rovv.
    - If a broken client asks a non-exit router to connect somewhere,
      do not even do the DNS lookup before rejecting the connection.
      Fixes another case of bug 619. Patch from rovv.
    - When a relay gets a create cell it can't decrypt (e.g. because it's
      using the wrong onion key), we were dropping it and letting the
      client time out. Now actually answer with a destroy cell. Fixes
      bug 904. Bugfix on 0.0.2pre8.

  o Minor bugfixes (hidden services):
    - Do not throw away existing introduction points on SIGHUP. Bugfix on
      0.0.6pre1. Patch by Karsten. Fixes bug 874.

  o Minor features:
    - Report the case where all signatures in a detached set are rejected
      differently than the case where there is an error handling the
      detached set.
    - When we realize that another process has modified our cached
      descriptors, print out a more useful error message rather than
      triggering an assertion. Fixes bug 885. Patch from Karsten.
    - Implement the 0x20 hack to better resist DNS poisoning: set the
      case on outgoing DNS requests randomly, and reject responses that do
      not match the case correctly. This logic can be disabled with the
      ServerDNSRamdomizeCase setting, if you are using one of the 0.3%
      of servers that do not reliably preserve case in replies. See
      "Increased DNS Forgery Resistance through 0x20-Bit Encoding"
      for more info.
    - Check DNS replies for more matching fields to better resist DNS
      poisoning.
    - Never use OpenSSL compression: it wastes RAM and CPU trying to
      compress cells, which are basically all encrypted, compressed, or
      both.


Changes in version 0.2.0.32 - 2008-11-20
  Tor 0.2.0.32 fixes a major security problem in Debian and Ubuntu
  packages (and maybe other packages) noticed by Theo de Raadt, fixes
  a smaller security flaw that might allow an attacker to access local
  services, further improves hidden service performance, and fixes a
  variety of other issues.

  o Security fixes:
    - The "User" and "Group" config options did not clear the
      supplementary group entries for the Tor process. The "User" option
      is now more robust, and we now set the groups to the specified
      user's primary group. The "Group" option is now ignored. For more
      detailed logging on credential switching, set CREDENTIAL_LOG_LEVEL
      in common/compat.c to LOG_NOTICE or higher. Patch by Jacob Appelbaum
      and Steven Murdoch. Bugfix on 0.0.2pre14. Fixes bug 848 and 857.
    - The "ClientDNSRejectInternalAddresses" config option wasn't being
      consistently obeyed: if an exit relay refuses a stream because its
      exit policy doesn't allow it, we would remember what IP address
      the relay said the destination address resolves to, even if it's
      an internal IP address. Bugfix on 0.2.0.7-alpha; patch by rovv.

  o Major bugfixes:
    - Fix a DOS opportunity during the voting signature collection process
      at directory authorities. Spotted by rovv. Bugfix on 0.2.0.x.

  o Major bugfixes (hidden services):
    - When fetching v0 and v2 rendezvous service descriptors in parallel,
      we were failing the whole hidden service request when the v0
      descriptor fetch fails, even if the v2 fetch is still pending and
      might succeed. Similarly, if the last v2 fetch fails, we were
      failing the whole hidden service request even if a v0 fetch is
      still pending. Fixes bug 814. Bugfix on 0.2.0.10-alpha.
    - When extending a circuit to a hidden service directory to upload a
      rendezvous descriptor using a BEGIN_DIR cell, almost 1/6 of all
      requests failed, because the router descriptor has not been
      downloaded yet. In these cases, do not attempt to upload the
      rendezvous descriptor, but wait until the router descriptor is
      downloaded and retry. Likewise, do not attempt to fetch a rendezvous
      descriptor from a hidden service directory for which the router
      descriptor has not yet been downloaded. Fixes bug 767. Bugfix
      on 0.2.0.10-alpha.

  o Minor bugfixes:
    - Fix several infrequent memory leaks spotted by Coverity.
    - When testing for libevent functions, set the LDFLAGS variable
      correctly. Found by Riastradh.
    - Avoid a bug where the FastFirstHopPK 0 option would keep Tor from
      bootstrapping with tunneled directory connections. Bugfix on
      0.1.2.5-alpha. Fixes bug 797. Found by Erwin Lam.
    - When asked to connect to A.B.exit:80, if we don't know the IP for A
      and we know that server B rejects most-but-not all connections to
      port 80, we would previously reject the connection. Now, we assume
      the user knows what they were asking for. Fixes bug 752. Bugfix
      on 0.0.9rc5. Diagnosed by BarkerJr.
    - If we overrun our per-second write limits a little, count this as
      having used up our write allocation for the second, and choke
      outgoing directory writes. Previously, we had only counted this when
      we had met our limits precisely. Fixes bug 824. Patch from by rovv.
      Bugfix on 0.2.0.x (??).
    - Remove the old v2 directory authority 'lefkada' from the default
      list. It has been gone for many months.
    - Stop doing unaligned memory access that generated bus errors on
      sparc64. Bugfix on 0.2.0.10-alpha. Fixes bug 862.
    - Make USR2 log-level switch take effect immediately. Bugfix on
      0.1.2.8-beta.

  o Minor bugfixes (controller):
    - Make DNS resolved events into "CLOSED", not "FAILED". Bugfix on
      0.1.2.5-alpha. Fix by Robert Hogan. Resolves bug 807.


Changes in version 0.2.0.31 - 2008-09-03
  Tor 0.2.0.31 addresses two potential anonymity issues, starts to fix
  a big bug we're seeing where in rare cases traffic from one Tor stream
  gets mixed into another stream, and fixes a variety of smaller issues.

  o Major bugfixes:
    - Make sure that two circuits can never exist on the same connection
      with the same circuit ID, even if one is marked for close. This
      is conceivably a bugfix for bug 779. Bugfix on 0.1.0.4-rc.
    - Relays now reject risky extend cells: if the extend cell includes
      a digest of all zeroes, or asks to extend back to the relay that
      sent the extend cell, tear down the circuit. Ideas suggested
      by rovv.
    - If not enough of our entry guards are available so we add a new
      one, we might use the new one even if it overlapped with the
      current circuit's exit relay (or its family). Anonymity bugfix
      pointed out by rovv.

  o Minor bugfixes:
    - Recover 3-7 bytes that were wasted per memory chunk. Fixes bug
      794; bug spotted by rovv. Bugfix on 0.2.0.1-alpha.
    - Correctly detect the presence of the linux/netfilter_ipv4.h header
      when building against recent kernels. Bugfix on 0.1.2.1-alpha.
    - Pick size of default geoip filename string correctly on windows.
      Fixes bug 806. Bugfix on 0.2.0.30.
    - Make the autoconf script accept the obsolete --with-ssl-dir
      option as an alias for the actually-working --with-openssl-dir
      option. Fix the help documentation to recommend --with-openssl-dir.
      Based on a patch by "Dave". Bugfix on 0.2.0.1-alpha.
    - When using the TransPort option on OpenBSD, and using the User
      option to change UID and drop privileges, make sure to open
      /dev/pf before dropping privileges. Fixes bug 782. Patch from
      Christopher Davis. Bugfix on 0.1.2.1-alpha.
    - Try to attach connections immediately upon receiving a RENDEZVOUS2
      or RENDEZVOUS_ESTABLISHED cell. This can save a second or two
      on the client side when connecting to a hidden service. Bugfix
      on 0.0.6pre1. Found and fixed by Christian Wilms; resolves bug 743.
    - When closing an application-side connection because its circuit is
      getting torn down, generate the stream event correctly. Bugfix on
      0.1.2.x. Anonymous patch.


Changes in version 0.2.0.30 - 2008-07-15
  This new stable release switches to a more efficient directory
  distribution design, adds features to make connections to the Tor
  network harder to block, allows Tor to act as a DNS proxy, adds separate
  rate limiting for relayed traffic to make it easier for clients to
  become relays, fixes a variety of potential anonymity problems, and
  includes the usual huge pile of other features and bug fixes.

  o New v3 directory design:
    - Tor now uses a new way to learn about and distribute information
      about the network: the directory authorities vote on a common
      network status document rather than each publishing their own
      opinion. Now clients and caches download only one networkstatus
      document to bootstrap, rather than downloading one for each
      authority. Clients only download router descriptors listed in
      the consensus. Implements proposal 101; see doc/spec/dir-spec.txt
      for details.
    - Set up moria1, tor26, and dizum as v3 directory authorities
      in addition to being v2 authorities. Also add three new ones:
      ides (run by Mike Perry), gabelmoo (run by Karsten Loesing), and
      dannenberg (run by CCC).
    - Switch to multi-level keys for directory authorities: now their
      long-term identity key can be kept offline, and they periodically
      generate a new signing key. Clients fetch the "key certificates"
      to keep up to date on the right keys. Add a standalone tool
      "tor-gencert" to generate key certificates. Implements proposal 103.
    - Add a new V3AuthUseLegacyKey config option to make it easier for
      v3 authorities to change their identity keys if another bug like
      Debian's OpenSSL RNG flaw appears.
    - Authorities and caches fetch the v2 networkstatus documents
      less often, now that v3 is recommended.

  o Make Tor connections stand out less on the wire:
    - Use an improved TLS handshake designed by Steven Murdoch in proposal
      124, as revised in proposal 130. The new handshake is meant to
      be harder for censors to fingerprint, and it adds the ability
      to detect certain kinds of man-in-the-middle traffic analysis
      attacks. The new handshake format includes version negotiation for
      OR connections as described in proposal 105, which will allow us
      to improve Tor's link protocol more safely in the future.
    - Enable encrypted directory connections by default for non-relays,
      so censor tools that block Tor directory connections based on their
      plaintext patterns will no longer work. This means Tor works in
      certain censored countries by default again.
    - Stop including recognizeable strings in the commonname part of
      Tor's x509 certificates.

  o Implement bridge relays:
    - Bridge relays (or "bridges" for short) are Tor relays that aren't
      listed in the main Tor directory. Since there is no complete public
      list of them, even an ISP that is filtering connections to all the
      known Tor relays probably won't be able to block all the bridges.
      See doc/design-paper/blocking.pdf and proposal 125 for details.
    - New config option BridgeRelay that specifies you want to be a
      bridge relay rather than a normal relay. When BridgeRelay is set
      to 1, then a) you cache dir info even if your DirPort ins't on,
      and b) the default for PublishServerDescriptor is now "bridge"
      rather than "v2,v3".
    - New config option "UseBridges 1" for clients that want to use bridge
      relays instead of ordinary entry guards. Clients then specify
      bridge relays by adding "Bridge" lines to their config file. Users
      can learn about a bridge relay either manually through word of
      mouth, or by one of our rate-limited mechanisms for giving out
      bridge addresses without letting an attacker easily enumerate them
      all. See https://www.torproject.org/bridges for details.
    - Bridge relays behave like clients with respect to time intervals
      for downloading new v3 consensus documents -- otherwise they
      stand out. Bridge users now wait until the end of the interval,
      so their bridge relay will be sure to have a new consensus document.

  o Implement bridge directory authorities:
    - Bridge authorities are like normal directory authorities, except
      they don't serve a list of known bridges. Therefore users that know
      a bridge's fingerprint can fetch a relay descriptor for that bridge,
      including fetching updates e.g. if the bridge changes IP address,
      yet an attacker can't just fetch a list of all the bridges.
    - Set up Tonga as the default bridge directory authority.
    - Bridge authorities refuse to serve bridge descriptors or other
      bridge information over unencrypted connections (that is, when
      responding to direct DirPort requests rather than begin_dir cells.)
    - Bridge directory authorities do reachability testing on the
      bridges they know. They provide router status summaries to the
      controller via "getinfo ns/purpose/bridge", and also dump summaries
      to a file periodically, so we can keep internal stats about which
      bridges are functioning.
    - If bridge users set the UpdateBridgesFromAuthority config option,
      but the digest they ask for is a 404 on the bridge authority,
      they fall back to contacting the bridge directly.
    - Bridges always use begin_dir to publish their server descriptor to
      the bridge authority using an anonymous encrypted tunnel.
    - Early work on a "bridge community" design: if bridge authorities set
      the BridgePassword config option, they will serve a snapshot of
      known bridge routerstatuses from their DirPort to anybody who
      knows that password. Unset by default.
    - Tor now includes an IP-to-country GeoIP file, so bridge relays can
      report sanitized aggregated summaries in their extra-info documents
      privately to the bridge authority, listing which countries are
      able to reach them. We hope this mechanism will let us learn when
      certain countries start trying to block bridges.
    - Bridge authorities write bridge descriptors to disk, so they can
      reload them after a reboot. They can also export the descriptors
      to other programs, so we can distribute them to blocked users via
      the BridgeDB interface, e.g. via https://bridges.torproject.org/
      and bridges@torproject.org.

  o Tor can be a DNS proxy:
    - The new client-side DNS proxy feature replaces the need for
      dns-proxy-tor: Just set "DNSPort 9999", and Tor will now listen
      for DNS requests on port 9999, use the Tor network to resolve them
      anonymously, and send the reply back like a regular DNS server.
      The code still only implements a subset of DNS.
    - Add a new AutomapHostsOnResolve option: when it is enabled, any
      resolve request for hosts matching a given pattern causes Tor to
      generate an internal virtual address mapping for that host. This
      allows DNSPort to work sensibly with hidden service users. By
      default, .exit and .onion addresses are remapped; the list of
      patterns can be reconfigured with AutomapHostsSuffixes.
    - Add an "-F" option to tor-resolve to force a resolve for a .onion
      address. Thanks to the AutomapHostsOnResolve option, this is no
      longer a completely silly thing to do.

  o Major features (relay usability):
    - New config options RelayBandwidthRate and RelayBandwidthBurst:
      a separate set of token buckets for relayed traffic. Right now
      relayed traffic is defined as answers to directory requests, and
      OR connections that don't have any local circuits on them. See
      proposal 111 for details.
    - Create listener connections before we setuid to the configured
      User and Group. Now non-Windows users can choose port values
      under 1024, start Tor as root, and have Tor bind those ports
      before it changes to another UID. (Windows users could already
      pick these ports.)
    - Added a new ConstrainedSockets config option to set SO_SNDBUF and
      SO_RCVBUF on TCP sockets. Hopefully useful for Tor servers running
      on "vserver" accounts. Patch from coderman.

  o Major features (directory authorities):
    - Directory authorities track weighted fractional uptime and weighted
      mean-time-between failures for relays. WFU is suitable for deciding
      whether a node is "usually up", while MTBF is suitable for deciding
      whether a node is "likely to stay up." We need both, because
      "usually up" is a good requirement for guards, while "likely to
      stay up" is a good requirement for long-lived connections.
    - Directory authorities use a new formula for selecting which relays
      to advertise as Guards: they must be in the top 7/8 in terms of
      how long we have known about them, and above the median of those
      nodes in terms of weighted fractional uptime.
    - Directory authorities use a new formula for selecting which relays
      to advertise as Stable: when we have 4 or more days of data, use
      median measured MTBF rather than median declared uptime. Implements
      proposal 108.
    - Directory authorities accept and serve "extra info" documents for
      routers. Routers now publish their bandwidth-history lines in the
      extra-info docs rather than the main descriptor. This step saves
      60% (!) on compressed router descriptor downloads. Servers upload
      extra-info docs to any authority that accepts them; directory
      authorities now allow multiple router descriptors and/or extra
      info documents to be uploaded in a single go. Authorities, and
      caches that have been configured to download extra-info documents,
      download them as needed. Implements proposal 104.
    - Authorities now list relays who have the same nickname as
      a different named relay, but list them with a new flag:
      "Unnamed". Now we can make use of relays that happen to pick the
      same nickname as a server that registered two years ago and then
      disappeared. Implements proposal 122.
    - Store routers in a file called cached-descriptors instead of in
      cached-routers. Initialize cached-descriptors from cached-routers
      if the old format is around. The new format allows us to store
      annotations along with descriptors, to record the time we received
      each descriptor, its source, and its purpose: currently one of
      general, controller, or bridge.

  o Major features (other):
    - New config options WarnPlaintextPorts and RejectPlaintextPorts so
      Tor can warn and/or refuse connections to ports commonly used with
      vulnerable-plaintext protocols. Currently we warn on ports 23,
      109, 110, and 143, but we don't reject any. Based on proposal 129
      by Kevin Bauer and Damon McCoy.
    - Integrate Karsten Loesing's Google Summer of Code project to publish
      hidden service descriptors on a set of redundant relays that are a
      function of the hidden service address. Now we don't have to rely
      on three central hidden service authorities for publishing and
      fetching every hidden service descriptor. Implements proposal 114.
    - Allow tunnelled directory connections to ask for an encrypted
      "begin_dir" connection or an anonymized "uses a full Tor circuit"
      connection independently. Now we can make anonymized begin_dir
      connections for (e.g.) more secure hidden service posting and
      fetching.

  o Major bugfixes (crashes and assert failures):
    - Stop imposing an arbitrary maximum on the number of file descriptors
      used for busy servers. Bug reported by Olaf Selke; patch from
      Sebastian Hahn.
    - Avoid possible failures when generating a directory with routers
      with over-long versions strings, or too many flags set.
    - Fix a rare assert error when we're closing one of our threads:
      use a mutex to protect the list of logs, so we never write to the
      list as it's being freed. Fixes the very rare bug 575, which is
      kind of the revenge of bug 222.
    - Avoid segfault in the case where a badly behaved v2 versioning
      directory sends a signed networkstatus with missing client-versions.
    - When we hit an EOF on a log (probably because we're shutting down),
      don't try to remove the log from the list: just mark it as
      unusable. (Bulletproofs against bug 222.)

  o Major bugfixes (code security fixes):
    - Detect size overflow in zlib code. Reported by Justin Ferguson and
      Dan Kaminsky.
    - Rewrite directory tokenization code to never run off the end of
      a string. Fixes bug 455. Patch from croup.
    - Be more paranoid about overwriting sensitive memory on free(),
      as a defensive programming tactic to ensure forward secrecy.

  o Major bugfixes (anonymity fixes):
    - Reject requests for reverse-dns lookup of names that are in
      a private address space. Patch from lodger.
    - Never report that we've used more bandwidth than we're willing to
      relay: it leaks how much non-relay traffic we're using. Resolves
      bug 516.
    - As a client, do not believe any server that tells us that an
      address maps to an internal address space.
    - Warn about unsafe ControlPort configurations.
    - Directory authorities now call routers Fast if their bandwidth is
      at least 100KB/s, and consider their bandwidth adequate to be a
      Guard if it is at least 250KB/s, no matter the medians. This fix
      complements proposal 107.
    - Directory authorities now never mark more than 2 servers per IP as
      Valid and Running (or 5 on addresses shared by authorities).
      Implements proposal 109, by Kevin Bauer and Damon McCoy.
    - If we're a relay, avoid picking ourselves as an introduction point,
      a rendezvous point, or as the final hop for internal circuits. Bug
      reported by taranis and lodger.
    - Exit relays that are used as a client can now reach themselves
      using the .exit notation, rather than just launching an infinite
      pile of circuits. Fixes bug 641. Reported by Sebastian Hahn.
    - Fix a bug where, when we were choosing the 'end stream reason' to
      put in our relay end cell that we send to the exit relay, Tor
      clients on Windows were sometimes sending the wrong 'reason'. The
      anonymity problem is that exit relays may be able to guess whether
      the client is running Windows, thus helping partition the anonymity
      set. Down the road we should stop sending reasons to exit relays,
      or otherwise prevent future versions of this bug.
    - Only update guard status (usable / not usable) once we have
      enough directory information. This was causing us to discard all our
      guards on startup if we hadn't been running for a few weeks. Fixes
      bug 448.
    - When our directory information has been expired for a while, stop
      being willing to build circuits using it. Fixes bug 401.

  o Major bugfixes (peace of mind for relay operators)
    - Non-exit relays no longer answer "resolve" relay cells, so they
      can't be induced to do arbitrary DNS requests. (Tor clients already
      avoid using non-exit relays for resolve cells, but now servers
      enforce this too.) Fixes bug 619. Patch from lodger.
    - When we setconf ClientOnly to 1, close any current OR and Dir
      listeners. Reported by mwenge.

  o Major bugfixes (other):
    - If we only ever used Tor for hidden service lookups or posts, we
      would stop building circuits and start refusing connections after
      24 hours, since we falsely believed that Tor was dormant. Reported
      by nwf.
    - Add a new __HashedControlSessionPassword option for controllers
      to use for one-off session password hashes that shouldn't get
      saved to disk by SAVECONF --- Vidalia users were accumulating a
      pile of HashedControlPassword lines in their torrc files, one for
      each time they had restarted Tor and then clicked Save. Make Tor
      automatically convert "HashedControlPassword" to this new option but
      only when it's given on the command line. Partial fix for bug 586.
    - Patch from "Andrew S. Lists" to catch when we contact a directory
      mirror at IP address X and he says we look like we're coming from
      IP address X. Otherwise this would screw up our address detection.
    - Reject uploaded descriptors and extrainfo documents if they're
      huge. Otherwise we'll cache them all over the network and it'll
      clog everything up. Suggested by Aljosha Judmayer.
    - When a hidden service was trying to establish an introduction point,
      and Tor *did* manage to reuse one of the preemptively built
      circuits, it didn't correctly remember which one it used,
      so it asked for another one soon after, until there were no
      more preemptive circuits, at which point it launched one from
      scratch. Bugfix on 0.0.9.x.

  o Rate limiting and load balancing improvements:
    - When we add data to a write buffer in response to the data on that
      write buffer getting low because of a flush, do not consider the
      newly added data as a candidate for immediate flushing, but rather
      make it wait until the next round of writing. Otherwise, we flush
      and refill recursively, and a single greedy TLS connection can
      eat all of our bandwidth.
    - When counting the number of bytes written on a TLS connection,
      look at the BIO actually used for writing to the network, not
      at the BIO used (sometimes) to buffer data for the network.
      Looking at different BIOs could result in write counts on the
      order of ULONG_MAX. Fixes bug 614.
    - If we change our MaxAdvertisedBandwidth and then reload torrc,
      Tor won't realize it should publish a new relay descriptor. Fixes
      bug 688, reported by mfr.
    - Avoid using too little bandwidth when our clock skips a few seconds.
    - Choose which bridge to use proportional to its advertised bandwidth,
      rather than uniformly at random. This should speed up Tor for
      bridge users. Also do this for people who set StrictEntryNodes.

  o Bootstrapping faster and building circuits more intelligently:
    - Fix bug 660 that was preventing us from knowing that we should
      preemptively build circuits to handle expected directory requests.
    - When we're checking if we have enough dir info for each relay
      to begin establishing circuits, make sure that we actually have
      the descriptor listed in the consensus, not just any descriptor.
    - Correctly notify one-hop connections when a circuit build has
      failed. Possible fix for bug 669. Found by lodger.
    - Clients now hold circuitless TLS connections open for 1.5 times
      MaxCircuitDirtiness (15 minutes), since it is likely that they'll
      rebuild a new circuit over them within that timeframe. Previously,
      they held them open only for KeepalivePeriod (5 minutes).

  o Performance improvements (memory):
    - Add OpenBSD malloc code from "phk" as an optional malloc
      replacement on Linux: some glibc libraries do very poorly with
      Tor's memory allocation patterns. Pass --enable-openbsd-malloc to
      ./configure to get the replacement malloc code.
    - Switch our old ring buffer implementation for one more like that
      used by free Unix kernels. The wasted space in a buffer with 1mb
      of data will now be more like 8k than 1mb. The new implementation
      also avoids realloc();realloc(); patterns that can contribute to
      memory fragmentation.
    - Change the way that Tor buffers data that it is waiting to write.
      Instead of queueing data cells in an enormous ring buffer for each
      client->OR or OR->OR connection, we now queue cells on a separate
      queue for each circuit. This lets us use less slack memory, and
      will eventually let us be smarter about prioritizing different kinds
      of traffic.
    - Reference-count and share copies of address policy entries; only 5%
      of them were actually distinct.
    - Tune parameters for cell pool allocation to minimize amount of
      RAM overhead used.
    - Keep unused 4k and 16k buffers on free lists, rather than wasting 8k
      for every single inactive connection_t. Free items from the
      4k/16k-buffer free lists when they haven't been used for a while.
    - Make memory debugging information describe more about history
      of cell allocation, so we can help reduce our memory use.
    - Be even more aggressive about releasing RAM from small
      empty buffers. Thanks to our free-list code, this shouldn't be too
      performance-intensive.
    - Log malloc statistics from mallinfo() on platforms where it exists.
    - Use memory pools to allocate cells with better speed and memory
      efficiency, especially on platforms where malloc() is inefficient.
    - Add a --with-tcmalloc option to the configure script to link
      against tcmalloc (if present). Does not yet search for non-system
      include paths.

  o Performance improvements (socket management):
    - Count the number of open sockets separately from the number of
      active connection_t objects. This will let us avoid underusing
      our allocated connection limit.
    - We no longer use socket pairs to link an edge connection to an
      anonymous directory connection or a DirPort test connection.
      Instead, we track the link internally and transfer the data
      in-process. This saves two sockets per "linked" connection (at the
      client and at the server), and avoids the nasty Windows socketpair()
      workaround.
    - We were leaking a file descriptor if Tor started with a zero-length
      cached-descriptors file. Patch by "freddy77".

  o Performance improvements (CPU use):
    - Never walk through the list of logs if we know that no log target
      is interested in a given message.
    - Call routerlist_remove_old_routers() much less often. This should
      speed startup, especially on directory caches.
    - Base64 decoding was actually showing up on our profile when parsing
      the initial descriptor file; switch to an in-process all-at-once
      implementation that's about 3.5x times faster than calling out to
      OpenSSL.
    - Use a slightly simpler string hashing algorithm (copying Python's
      instead of Java's) and optimize our digest hashing algorithm to take
      advantage of 64-bit platforms and to remove some possibly-costly
      voodoo.
    - When implementing AES counter mode, update only the portions of the
      counter buffer that need to change, and don't keep separate
      network-order and host-order counters on big-endian hosts (where
      they are the same).
    - Add an in-place version of aes_crypt() so that we can avoid doing a
      needless memcpy() call on each cell payload.
    - Use Critical Sections rather than Mutexes for synchronizing threads
      on win32; Mutexes are heavier-weight, and designed for synchronizing
      between processes.

  o Performance improvements (bandwidth use):
    - Don't try to launch new descriptor downloads quite so often when we
      already have enough directory information to build circuits.
    - Version 1 directories are no longer generated in full. Instead,
      authorities generate and serve "stub" v1 directories that list
      no servers. This will stop Tor versions 0.1.0.x and earlier from
      working, but (for security reasons) nobody should be running those
      versions anyway.
    - Avoid going directly to the directory authorities even if you're a
      relay, if you haven't found yourself reachable yet or if you've
      decided not to advertise your dirport yet. Addresses bug 556.
    - If we've gone 12 hours since our last bandwidth check, and we
      estimate we have less than 50KB bandwidth capacity but we could
      handle more, do another bandwidth test.
    - Support "If-Modified-Since" when answering HTTP requests for
      directories, running-routers documents, and v2 and v3 networkstatus
      documents. (There's no need to support it for router descriptors,
      since those are downloaded by descriptor digest.)
    - Stop fetching directory info so aggressively if your DirPort is
      on but your ORPort is off; stop fetching v2 dir info entirely.
      You can override these choices with the new FetchDirInfoEarly
      config option.

  o Changed config option behavior (features):
    - Configuration files now accept C-style strings as values. This
      helps encode characters not allowed in the current configuration
      file format, such as newline or #. Addresses bug 557.
    - Add hidden services and DNSPorts to the list of things that make
      Tor accept that it has running ports. Change starting Tor with no
      ports from a fatal error to a warning; we might change it back if
      this turns out to confuse anybody. Fixes bug 579.
    - Make PublishServerDescriptor default to 1, so the default doesn't
      have to change as we invent new directory protocol versions.
    - Allow people to say PreferTunnelledDirConns rather than
      PreferTunneledDirConns, for those alternate-spellers out there.
    - Raise the default BandwidthRate/BandwidthBurst to 5MB/10MB, to
      accommodate the growing number of servers that use the default
      and are reaching it.
    - Make it possible to enable HashedControlPassword and
      CookieAuthentication at the same time.
    - When a TrackHostExits-chosen exit fails too many times in a row,
      stop using it. Fixes bug 437.

  o Changed config option behavior (bugfixes):
    - Do not read the configuration file when we've only been told to
      generate a password hash. Fixes bug 643. Bugfix on 0.0.9pre5. Fix
      based on patch from Sebastian Hahn.
    - Actually validate the options passed to AuthDirReject,
      AuthDirInvalid, AuthDirBadDir, and AuthDirBadExit.
    - Make "ClientOnly 1" config option disable directory ports too.
    - Don't stop fetching descriptors when FetchUselessDescriptors is
      set, even if we stop asking for circuits. Bug reported by tup
      and ioerror.
    - Servers used to decline to publish their DirPort if their
      BandwidthRate or MaxAdvertisedBandwidth were below a threshold. Now
      they look only at BandwidthRate and RelayBandwidthRate.
    - Treat "2gb" when given in torrc for a bandwidth as meaning 2gb,
      minus 1 byte: the actual maximum declared bandwidth.
    - Make "TrackHostExits ." actually work. Bugfix on 0.1.0.x.
    - Make the NodeFamilies config option work. (Reported by
      lodger -- it has never actually worked, even though we added it
      in Oct 2004.)
    - If Tor is invoked from something that isn't a shell (e.g. Vidalia),
      now we expand "-f ~/.tor/torrc" correctly. Suggested by Matt Edman.

  o New config options:
    - New configuration options AuthDirMaxServersPerAddr and
      AuthDirMaxServersperAuthAddr to override default maximum number
      of servers allowed on a single IP address. This is important for
      running a test network on a single host.
    - Three new config options (AlternateDirAuthority,
      AlternateBridgeAuthority, and AlternateHSAuthority) that let the
      user selectively replace the default directory authorities by type,
      rather than the all-or-nothing replacement that DirServer offers.
    - New config options AuthDirBadDir and AuthDirListBadDirs for
      authorities to mark certain relays as "bad directories" in the
      networkstatus documents. Also supports the "!baddir" directive in
      the approved-routers file.
    - New config option V2AuthoritativeDirectory that all v2 directory
      authorities must set. This lets v3 authorities choose not to serve
      v2 directory information.

  o Minor features (other):
    - When we're not serving v2 directory information, there is no reason
      to actually keep any around. Remove the obsolete files and directory
      on startup if they are very old and we aren't going to serve them.
    - When we negotiate a v2 link-layer connection (not yet implemented),
      accept RELAY_EARLY cells and turn them into RELAY cells if we've
      negotiated a v1 connection for their next step. Initial steps for
      proposal 110.
    - When we have no consensus, check FallbackNetworkstatusFile (defaults
      to $PREFIX/share/tor/fallback-consensus) for a consensus. This way
      we can start out knowing some directory caches. We don't ship with
      a fallback consensus by default though, because it was making
      bootstrapping take too long while we tried many down relays.
    - Authorities send back an X-Descriptor-Not-New header in response to
      an accepted-but-discarded descriptor upload. Partially implements
      fix for bug 535.
    - If we find a cached-routers file that's been sitting around for more
      than 28 days unmodified, then most likely it's a leftover from
      when we upgraded to 0.2.0.8-alpha. Remove it. It has no good
      routers anyway.
    - When we (as a cache) download a descriptor because it was listed
      in a consensus, remember when the consensus was supposed to expire,
      and don't expire the descriptor until then.
    - Optionally (if built with -DEXPORTMALLINFO) export the output
      of mallinfo via http, as tor/mallinfo.txt. Only accessible
      from localhost.
    - Tag every guard node in our state file with the version that
      we believe added it, or with our own version if we add it. This way,
      if a user temporarily runs an old version of Tor and then switches
      back to a new one, she doesn't automatically lose her guards.
    - When somebody requests a list of statuses or servers, and we have
      none of those, return a 404 rather than an empty 200.
    - Merge in some (as-yet-unused) IPv6 address manipulation code. (Patch
      from croup.)
    - Add an HSAuthorityRecordStats option that hidden service authorities
      can use to track statistics of overall hidden service usage without
      logging information that would be as useful to an attacker.
    - Allow multiple HiddenServicePort directives with the same virtual
      port; when they occur, the user is sent round-robin to one
      of the target ports chosen at random.  Partially fixes bug 393 by
      adding limited ad-hoc round-robining.
    - Revamp file-writing logic so we don't need to have the entire
      contents of a file in memory at once before we write to disk. Tor,
      meet stdio.

  o Minor bugfixes (other):
    - Alter the code that tries to recover from unhandled write
      errors, to not try to flush onto a socket that's given us
      unhandled errors.
    - Directory mirrors no longer include a guess at the client's IP
      address if the connection appears to be coming from the same /24
      network; it was producing too many wrong guesses.
    - If we're trying to flush the last bytes on a connection (for
      example, when answering a directory request), reset the
      time-to-give-up timeout every time we manage to write something
      on the socket.
    - Reject router descriptors with out-of-range bandwidthcapacity or
      bandwidthburst values.
    - If we can't expand our list of entry guards (e.g. because we're
      using bridges or we have StrictEntryNodes set), don't mark relays
      down when they fail a directory request. Otherwise we're too quick
      to mark all our entry points down.
    - Authorities no longer send back "400 you're unreachable please fix
      it" errors to Tor servers that aren't online all the time. We're
      supposed to tolerate these servers now.
    - Let directory authorities startup even when they can't generate
      a descriptor immediately, e.g. because they don't know their
      address.
    - Correctly enforce that elements of directory objects do not appear
      more often than they are allowed to appear.
    - Stop allowing hibernating servers to be "stable" or "fast".
    - On Windows, we were preventing other processes from reading
      cached-routers while Tor was running. (Reported by janbar)
    - Check return values from pthread_mutex functions.
    - When opening /dev/null in finish_daemonize(), do not pass the
      O_CREAT flag. Fortify was complaining, and correctly so. Fixes
      bug 742; fix from Michael Scherer. Bugfix on 0.0.2pre19.

  o Controller features:
    - The GETCONF command now escapes and quotes configuration values
      that don't otherwise fit into the torrc file.
    - The SETCONF command now handles quoted values correctly.
    - Add "GETINFO/desc-annotations/id/<OR digest>" so controllers can
      ask about source, timestamp of arrival, purpose, etc. We need
      something like this to help Vidalia not do GeoIP lookups on bridge
      addresses.
    - Allow multiple HashedControlPassword config lines, to support
      multiple controller passwords.
    - Accept LF instead of CRLF on controller, since some software has a
      hard time generating real Internet newlines.
    - Add GETINFO values for the server status events
      "REACHABILITY_SUCCEEDED" and "GOOD_SERVER_DESCRIPTOR". Patch from
      Robert Hogan.
    - There is now an ugly, temporary "desc/all-recent-extrainfo-hack"
      GETINFO for Torstat to use until it can switch to using extrainfos.
    - New config option CookieAuthFile to choose a new location for the
      cookie authentication file, and config option
      CookieAuthFileGroupReadable to make it group-readable.
    - Add a SOURCE_ADDR field to STREAM NEW events so that controllers can
      match requests to applications. Patch from Robert Hogan.
    - Add a RESOLVE command to launch hostname lookups. Original patch
      from Robert Hogan.
    - Add GETINFO status/enough-dir-info to let controllers tell whether
      Tor has downloaded sufficient directory information. Patch from Tup.
    - You can now use the ControlSocket option to tell Tor to listen for
      controller connections on Unix domain sockets on systems that
      support them. Patch from Peter Palfrader.
    - New "GETINFO address-mappings/*" command to get address mappings
      with expiry information. "addr-mappings/*" is now deprecated.
      Patch from Tup.
    - Add a new config option __DisablePredictedCircuits designed for
      use by the controller, when we don't want Tor to build any circuits
      preemptively.
    - Let the controller specify HOP=%d as an argument to ATTACHSTREAM,
      so we can exit from the middle of the circuit.
    - Implement "getinfo status/circuit-established".
    - Implement "getinfo status/version/..." so a controller can tell
      whether the current version is recommended, and whether any versions
      are good, and how many authorities agree. Patch from "shibz".
    - Controllers should now specify cache=no or cache=yes when using
      the +POSTDESCRIPTOR command.
    - Add a "PURPOSE=" argument to "STREAM NEW" events, as suggested by
      Robert Hogan. Fixes the first part of bug 681.
    - When reporting clock skew, and we know that the clock is _at least
      as skewed_ as some value, but we don't know the actual value,
      report the value as a "minimum skew."

  o Controller bugfixes:
    - Generate "STATUS_SERVER" events rather than misspelled
      "STATUS_SEVER" events. Caught by mwenge.
    - Reject controller commands over 1MB in length, so rogue
      processes can't run us out of memory.
    - Change the behavior of "getinfo status/good-server-descriptor"
      so it doesn't return failure when any authority disappears.
    - Send NAMESERVER_STATUS messages for a single failed nameserver
      correctly.
    - When the DANGEROUS_VERSION controller status event told us we're
      running an obsolete version, it used the string "OLD" to describe
      it. Yet the "getinfo" interface used the string "OBSOLETE". Now use
      "OBSOLETE" in both cases.
    - Respond to INT and TERM SIGNAL commands before we execute the
      signal, in case the signal shuts us down. We had a patch in
      0.1.2.1-alpha that tried to do this by queueing the response on
      the connection's buffer before shutting down, but that really
      isn't the same thing at all. Bug located by Matt Edman.
    - Provide DNS expiry times in GMT, not in local time. For backward
      compatibility, ADDRMAP events only provide GMT expiry in an extended
      field. "GETINFO address-mappings" always does the right thing.
    - Use CRLF line endings properly in NS events.
    - Make 'getinfo fingerprint' return a 551 error if we're not a
      server, so we match what the control spec claims we do. Reported
      by daejees.
    - Fix a typo in an error message when extendcircuit fails that
      caused us to not follow the \r\n-based delimiter protocol. Reported
      by daejees.
    - When tunneling an encrypted directory connection, and its first
      circuit fails, do not leave it unattached and ask the controller
      to deal. Fixes the second part of bug 681.
    - Treat some 403 responses from directory servers as INFO rather than
      WARN-severity events.

  o Portability / building / compiling:
    - When building with --enable-gcc-warnings, check for whether Apple's
      warning "-Wshorten-64-to-32" is available.
    - Support compilation to target iPhone; patch from cjacker huang.
      To build for iPhone, pass the --enable-iphone option to configure.
    - Port Tor to build and run correctly on Windows CE systems, using
      the wcecompat library. Contributed by Valerio Lupi.
    - Detect non-ASCII platforms (if any still exist) and refuse to
      build there: some of our code assumes that 'A' is 65 and so on.
    - Clear up some MIPSPro compiler warnings.
    - Make autoconf search for libevent, openssl, and zlib consistently.
    - Update deprecated macros in configure.in.
    - When warning about missing headers, tell the user to let us
      know if the compile succeeds anyway, so we can downgrade the
      warning.
    - Include the current subversion revision as part of the version
      string: either fetch it directly if we're in an SVN checkout, do
      some magic to guess it if we're in an SVK checkout, or use
      the last-detected version if we're building from a .tar.gz.
      Use this version consistently in log messages.
    - Correctly report platform name on Windows 95 OSR2 and Windows 98 SE.
    - Read resolv.conf files correctly on platforms where read() returns
      partial results on small file reads.
    - Build without verbose warnings even on gcc 4.2 and 4.3.
    - On Windows, correctly detect errors when listing the contents of
      a directory. Fix from lodger.
    - Run 'make test' as part of 'make dist', so we stop releasing so
      many development snapshots that fail their unit tests.
    - Add support to detect Libevent versions in the 1.4.x series
      on mingw.
    - Add command-line arguments to unit-test executable so that we can
      invoke any chosen test from the command line rather than having
      to run the whole test suite at once; and so that we can turn on
      logging for the unit tests.
    - Do not automatically run configure from autogen.sh. This
      non-standard behavior tended to annoy people who have built other
      programs.
    - Fix a macro/CPP interaction that was confusing some compilers:
      some GCCs don't like #if/#endif pairs inside macro arguments.
      Fixes bug 707.
    - Fix macro collision between OpenSSL 0.9.8h and Windows headers.
      Fixes bug 704; fix from Steven Murdoch.
    - Correctly detect transparent proxy support on Linux hosts that
      require in.h to be included before netfilter_ipv4.h.  Patch
      from coderman.

  o Logging improvements:
    - When we haven't had any application requests lately, don't bother
      logging that we have expired a bunch of descriptors.
    - When attempting to open a logfile fails, tell us why.
    - Only log guard node status when guard node status has changed.
    - Downgrade the 3 most common "INFO" messages to "DEBUG". This will
      make "INFO" 75% less verbose.
    - When SafeLogging is disabled, log addresses along with all TLS
      errors.
    - Report TLS "zero return" case as a "clean close" and "IO error"
      as a "close". Stop calling closes "unexpected closes": existing
      Tors don't use SSL_close(), so having a connection close without
      the TLS shutdown handshake is hardly unexpected.
    - When we receive a consensus from the future, warn about skew.
    - Make "not enough dir info yet" warnings describe *why* Tor feels
      it doesn't have enough directory info yet.
    - On the USR1 signal, when dmalloc is in use, log the top 10 memory
      consumers. (We already do this on HUP.)
    - Give more descriptive well-formedness errors for out-of-range
      hidden service descriptor/protocol versions.
    - Stop recommending that every server operator send mail to tor-ops.
      Resolves bug 597. Bugfix on 0.1.2.x.
    - Improve skew reporting: try to give the user a better log message
      about how skewed they are, and how much this matters.
    - New --quiet command-line option to suppress the default console log.
      Good in combination with --hash-password.
    - Don't complain that "your server has not managed to confirm that its
      ports are reachable" if we haven't been able to build any circuits
      yet.
    - Detect the reason for failing to mmap a descriptor file we just
      wrote, and give a more useful log message.  Fixes bug 533.
    - Always prepend "Bug: " to any log message about a bug.
    - When dumping memory usage, list bytes used in buffer memory
      free-lists.
    - When running with dmalloc, dump more stats on hup and on exit.
    - Put a platform string (e.g. "Linux i686") in the startup log
      message, so when people paste just their logs, we know if it's
      OpenBSD or Windows or what.
    - When logging memory usage, break down memory used in buffers by
      buffer type.
    - When we are reporting the DirServer line we just parsed, we were
      logging the second stanza of the key fingerprint, not the first.
    - Even though Windows is equally happy with / and \ as path separators,
      try to use \ consistently on Windows and / consistently on Unix: it
      makes the log messages nicer.
     - On OSX, stop warning the user that kqueue support in libevent is
      "experimental", since it seems to have worked fine for ages.

  o Contributed scripts and tools:
    - Update linux-tor-prio.sh script to allow QoS based on the uid of
      the Tor process. Patch from Marco Bonetti with tweaks from Mike
      Perry.
    - Include the "tor-ctrl.sh" bash script by Stefan Behte to provide
      Unix users an easy way to script their Tor process (e.g. by
      adjusting bandwidth based on the time of the day).
    - In the exitlist script, only consider the most recently published
      server descriptor for each server. Also, when the user requests
      a list of servers that _reject_ connections to a given address,
      explicitly exclude the IPs that also have servers that accept
      connections to that address. Resolves bug 405.
    - Include a new contrib/tor-exit-notice.html file that exit relay
      operators can put on their website to help reduce abuse queries.

  o Newly deprecated features:
    - The status/version/num-versioning and status/version/num-concurring
      GETINFO controller options are no longer useful in the v3 directory
      protocol: treat them as deprecated, and warn when they're used.
    - The RedirectExits config option is now deprecated.

  o Removed features:
    - Drop the old code to choke directory connections when the
      corresponding OR connections got full: thanks to the cell queue
      feature, OR conns don't get full any more.
    - Remove the old "dns worker" server DNS code: it hasn't been default
      since 0.1.2.2-alpha, and all the servers are using the new
      eventdns code.
    - Remove the code to generate the oldest (v1) directory format.
    - Remove support for the old bw_accounting file: we've been storing
      bandwidth accounting information in the state file since
      0.1.2.5-alpha. This may result in bandwidth accounting errors
      if you try to upgrade from 0.1.1.x or earlier, or if you try to
      downgrade to 0.1.1.x or earlier.
    - Drop support for OpenSSL version 0.9.6. Just about nobody was using
      it, it had no AES, and it hasn't seen any security patches since
      2004.
    - Stop overloading the circuit_t.onionskin field for both "onionskin
      from a CREATE cell that we are waiting for a cpuworker to be
      assigned" and "onionskin from an EXTEND cell that we are going to
      send to an OR as soon as we are connected". Might help with bug 600.
    - Remove the tor_strpartition() function: its logic was confused,
      and it was only used for one thing that could be implemented far
      more easily.
    - Remove the contrib scripts ExerciseServer.py, PathDemo.py,
      and TorControl.py, as they use the old v0 controller protocol,
      and are obsoleted by TorFlow anyway.
    - Drop support for v1 rendezvous descriptors, since we never used
      them anyway, and the code has probably rotted by now. Based on
      patch from Karsten Loesing.
    - Stop allowing address masks that do not correspond to bit prefixes.
      We have warned about these for a really long time; now it's time
      to reject them. (Patch from croup.)
    - Remove an optimization in the AES counter-mode code that assumed
      that the counter never exceeded 2^68. When the counter can be set
      arbitrarily as an IV (as it is by Karsten's new hidden services
      code), this assumption no longer holds.
    - Disable the SETROUTERPURPOSE controller command: it is now
      obsolete.


Changes in version 0.1.2.19 - 2008-01-17
  Tor 0.1.2.19 fixes a huge memory leak on exit relays, makes the default
  exit policy a little bit more conservative so it's safer to run an
  exit relay on a home system, and fixes a variety of smaller issues.

  o Security fixes:
    - Exit policies now reject connections that are addressed to a
      relay's public (external) IP address too, unless
      ExitPolicyRejectPrivate is turned off. We do this because too
      many relays are running nearby to services that trust them based
      on network address.

  o Major bugfixes:
    - When the clock jumps forward a lot, do not allow the bandwidth
      buckets to become negative. Fixes bug 544.
    - Fix a memory leak on exit relays; we were leaking a cached_resolve_t
      on every successful resolve. Reported by Mike Perry.
    - Purge old entries from the "rephist" database and the hidden
      service descriptor database even when DirPort is zero.
    - Stop thinking that 0.1.2.x directory servers can handle "begin_dir"
      requests. Should ease bugs 406 and 419 where 0.1.2.x relays are
      crashing or mis-answering these requests.
    - When we decide to send a 503 response to a request for servers, do
      not then also send the server descriptors: this defeats the whole
      purpose. Fixes bug 539.

  o Minor bugfixes:
    - Changing the ExitPolicyRejectPrivate setting should cause us to
      rebuild our server descriptor.
    - Fix handling of hex nicknames when answering controller requests for
      networkstatus by name, or when deciding whether to warn about
      unknown routers in a config option. (Patch from mwenge.)
    - Fix a couple of hard-to-trigger autoconf problems that could result
      in really weird results on platforms whose sys/types.h files define
      nonstandard integer types.
    - Don't try to create the datadir when running --verify-config or
      --hash-password. Resolves bug 540.
    - If we were having problems getting a particular descriptor from the
      directory caches, and then we learned about a new descriptor for
      that router, we weren't resetting our failure count. Reported
      by lodger.
    - Although we fixed bug 539 (where servers would send HTTP status 503
      responses _and_ send a body too), there are still servers out there
      that haven't upgraded. Therefore, make clients parse such bodies
      when they receive them.
    - Run correctly on systems where rlim_t is larger than unsigned long.
      This includes some 64-bit systems.
    - Run correctly on platforms (like some versions of OS X 10.5) where
      the real limit for number of open files is OPEN_FILES, not rlim_max
      from getrlimit(RLIMIT_NOFILES).
    - Avoid a spurious free on base64 failure.
    - Avoid segfaults on certain complex invocations of
      router_get_by_hexdigest().
    - Fix rare bug on REDIRECTSTREAM control command when called with no
      port set: it could erroneously report an error when none had
      happened.


Changes in version 0.1.2.18 - 2007-10-28
  Tor 0.1.2.18 fixes many problems including crash bugs, problems with
  hidden service introduction that were causing huge delays, and a big
  bug that was causing some servers to disappear from the network status
  lists for a few hours each day.

  o Major bugfixes (crashes):
    - If a connection is shut down abruptly because of something that
      happened inside connection_flushed_some(), do not call
      connection_finished_flushing(). Should fix bug 451:
      "connection_stop_writing: Assertion conn->write_event failed"
      Bugfix on 0.1.2.7-alpha.
    - Fix possible segfaults in functions called from
      rend_process_relay_cell().

  o Major bugfixes (hidden services):
    - Hidden services were choosing introduction points uniquely by
      hexdigest, but when constructing the hidden service descriptor
      they merely wrote the (potentially ambiguous) nickname.
    - Clients now use the v2 intro format for hidden service
      connections: they specify their chosen rendezvous point by identity
      digest rather than by (potentially ambiguous) nickname. These
      changes could speed up hidden service connections dramatically.

  o Major bugfixes (other):
    - Stop publishing a new server descriptor just because we get a
      HUP signal. This led (in a roundabout way) to some servers getting
      dropped from the networkstatus lists for a few hours each day.
    - When looking for a circuit to cannibalize, consider family as well
      as identity. Fixes bug 438. Bugfix on 0.1.0.x (which introduced
      circuit cannibalization).
    - When a router wasn't listed in a new networkstatus, we were leaving
      the flags for that router alone -- meaning it remained Named,
      Running, etc -- even though absence from the networkstatus means
      that it shouldn't be considered to exist at all anymore. Now we
      clear all the flags for routers that fall out of the networkstatus
      consensus. Fixes bug 529.

  o Minor bugfixes:
    - Don't try to access (or alter) the state file when running
      --list-fingerprint or --verify-config or --hash-password. Resolves
      bug 499.
    - When generating information telling us how to extend to a given
      router, do not try to include the nickname if it is
      absent. Resolves bug 467.
    - Fix a user-triggerable segfault in expand_filename(). (There isn't
      a way to trigger this remotely.)
    - When sending a status event to the controller telling it that an
      OR address is reachable, set the port correctly. (Previously we
      were reporting the dir port.)
    - Fix a minor memory leak whenever a controller sends the PROTOCOLINFO
      command. Bugfix on 0.1.2.17.
    - When loading bandwidth history, do not believe any information in
      the future. Fixes bug 434.
    - When loading entry guard information, do not believe any information
      in the future.
    - When we have our clock set far in the future and generate an
      onion key, then re-set our clock to be correct, we should not stop
      the onion key from getting rotated.
    - On some platforms, accept() can return a broken address. Detect
      this more quietly, and deal accordingly. Fixes bug 483.
    - It's not actually an error to find a non-pending entry in the DNS
      cache when canceling a pending resolve. Don't log unless stuff
      is fishy. Resolves bug 463.
    - Don't reset trusted dir server list when we set a configuration
      option. Patch from Robert Hogan.


Changes in version 0.1.2.17 - 2007-08-30
  Tor 0.1.2.17 features a new Vidalia version in the Windows and OS
  X bundles. Vidalia 0.0.14 makes authentication required for the
  ControlPort in the default configuration, which addresses important
  security risks. Everybody who uses Vidalia (or another controller)
  should upgrade.

  In addition, this Tor update fixes major load balancing problems with
  path selection, which should speed things up a lot once many people
  have upgraded.

  o Major bugfixes (security):
    - We removed support for the old (v0) control protocol. It has been
      deprecated since Tor 0.1.1.1-alpha, and keeping it secure has
      become more of a headache than it's worth.

  o Major bugfixes (load balancing):
    - When choosing nodes for non-guard positions, weight guards
      proportionally less, since they already have enough load. Patch
      from Mike Perry.
    - Raise the "max believable bandwidth" from 1.5MB/s to 10MB/s. This
      will allow fast Tor servers to get more attention.
    - When we're upgrading from an old Tor version, forget our current
      guards and pick new ones according to the new weightings. These
      three load balancing patches could raise effective network capacity
      by a factor of four. Thanks to Mike Perry for measurements.

  o Major bugfixes (stream expiration):
    - Expire not-yet-successful application streams in all cases if
      they've been around longer than SocksTimeout. Right now there are
      some cases where the stream will live forever, demanding a new
      circuit every 15 seconds. Fixes bug 454; reported by lodger.

  o Minor features (controller):
    - Add a PROTOCOLINFO controller command. Like AUTHENTICATE, it
      is valid before any authentication has been received. It tells
      a controller what kind of authentication is expected, and what
      protocol is spoken. Implements proposal 119.

  o Minor bugfixes (performance):
    - Save on most routerlist_assert_ok() calls in routerlist.c, thus
      greatly speeding up loading cached-routers from disk on startup.
    - Disable sentinel-based debugging for buffer code: we squashed all
      the bugs that this was supposed to detect a long time ago, and now
      its only effect is to change our buffer sizes from nice powers of
      two (which platform mallocs tend to like) to values slightly over
      powers of two (which make some platform mallocs sad).

  o Minor bugfixes (misc):
    - If exit bandwidth ever exceeds one third of total bandwidth, then
      use the correct formula to weight exit nodes when choosing paths.
      Based on patch from Mike Perry.
    - Choose perfectly fairly among routers when choosing by bandwidth and
      weighting by fraction of bandwidth provided by exits. Previously, we
      would choose with only approximate fairness, and correct ourselves
      if we ran off the end of the list.
    - If we require CookieAuthentication but we fail to write the
      cookie file, we would warn but not exit, and end up in a state
      where no controller could authenticate. Now we exit.
    - If we require CookieAuthentication, stop generating a new cookie
      every time we change any piece of our config.
    - Refuse to start with certain directory authority keys, and
      encourage people using them to stop.
    - Terminate multi-line control events properly. Original patch
      from tup.
    - Fix a minor memory leak when we fail to find enough suitable
      servers to choose a circuit.
    - Stop leaking part of the descriptor when we run into a particularly
      unparseable piece of it.


Changes in version 0.1.2.16 - 2007-08-01
  Tor 0.1.2.16 fixes a critical security vulnerability that allows a
  remote attacker in certain situations to rewrite the user's torrc
  configuration file. This can completely compromise anonymity of users
  in most configurations, including those running the Vidalia bundles,
  TorK, etc. Or worse.

  o Major security fixes:
    - Close immediately after missing authentication on control port;
      do not allow multiple authentication attempts.


Changes in version 0.1.2.15 - 2007-07-17
  Tor 0.1.2.15 fixes several crash bugs, fixes some anonymity-related
  problems, fixes compilation on BSD, and fixes a variety of other
  bugs. Everybody should upgrade.

  o Major bugfixes (compilation):
    - Fix compile on FreeBSD/NetBSD/OpenBSD. Oops.

  o Major bugfixes (crashes):
    - Try even harder not to dereference the first character after
      an mmap(). Reported by lodger.
    - Fix a crash bug in directory authorities when we re-number the
      routerlist while inserting a new router.
    - When the cached-routers file is an even multiple of the page size,
      don't run off the end and crash. (Fixes bug 455; based on idea
      from croup.)
    - Fix eventdns.c behavior on Solaris: It is critical to include
      orconfig.h _before_ sys/types.h, so that we can get the expected
      definition of _FILE_OFFSET_BITS.

  o Major bugfixes (security):
    - Fix a possible buffer overrun when using BSD natd support. Bug
      found by croup.
    - When sending destroy cells from a circuit's origin, don't include
      the reason for tearing down the circuit. The spec says we didn't,
      and now we actually don't. Reported by lodger.
    - Keep streamids from different exits on a circuit separate. This
      bug may have allowed other routers on a given circuit to inject
      cells into streams. Reported by lodger; fixes bug 446.
    - If there's a never-before-connected-to guard node in our list,
      never choose any guards past it. This way we don't expand our
      guard list unless we need to.

  o Minor bugfixes (guard nodes):
    - Weight guard selection by bandwidth, so that low-bandwidth nodes
      don't get overused as guards.

  o Minor bugfixes (directory):
    - Correctly count the number of authorities that recommend each
      version. Previously, we were under-counting by 1.
    - Fix a potential crash bug when we load many server descriptors at
      once and some of them make others of them obsolete. Fixes bug 458.

  o Minor bugfixes (hidden services):
    - Stop tearing down the whole circuit when the user asks for a
      connection to a port that the hidden service didn't configure.
      Resolves bug 444.

  o Minor bugfixes (misc):
    - On Windows, we were preventing other processes from reading
      cached-routers while Tor was running. Reported by janbar.
    - Fix a possible (but very unlikely) bug in picking routers by
      bandwidth. Add a log message to confirm that it is in fact
      unlikely. Patch from lodger.
    - Backport a couple of memory leak fixes.
    - Backport miscellaneous cosmetic bugfixes.


Changes in version 0.1.2.14 - 2007-05-25
  Tor 0.1.2.14 changes the addresses of two directory authorities (this
  change especially affects those who serve or use hidden services),
  and fixes several other crash- and security-related bugs.

  o Directory authority changes:
    - Two directory authorities (moria1 and moria2) just moved to new
      IP addresses. This change will particularly affect those who serve
      or use hidden services.

  o Major bugfixes (crashes):
    - If a directory server runs out of space in the connection table
      as it's processing a begin_dir request, it will free the exit stream
      but leave it attached to the circuit, leading to unpredictable
      behavior. (Reported by seeess, fixes bug 425.)
    - Fix a bug in dirserv_remove_invalid() that would cause authorities
      to corrupt memory under some really unlikely scenarios.
    - Tighten router parsing rules. (Bugs reported by Benedikt Boss.)
    - Avoid segfaults when reading from mmaped descriptor file. (Reported
      by lodger.)

  o Major bugfixes (security):
    - When choosing an entry guard for a circuit, avoid using guards
      that are in the same family as the chosen exit -- not just guards
      that are exactly the chosen exit. (Reported by lodger.)

  o Major bugfixes (resource management):
    - If a directory authority is down, skip it when deciding where to get
      networkstatus objects or descriptors. Otherwise we keep asking
      every 10 seconds forever. Fixes bug 384.
    - Count it as a failure if we fetch a valid network-status but we
      don't want to keep it. Otherwise we'll keep fetching it and keep
      not wanting to keep it. Fixes part of bug 422.
    - If all of our dirservers have given us bad or no networkstatuses
      lately, then stop hammering them once per minute even when we
      think they're failed. Fixes another part of bug 422.

  o Minor bugfixes:
    - Actually set the purpose correctly for descriptors inserted with
      purpose=controller.
    - When we have k non-v2 authorities in our DirServer config,
      we ignored the last k authorities in the list when updating our
      network-statuses.
    - Correctly back-off from requesting router descriptors that we are
      having a hard time downloading.
    - Read resolv.conf files correctly on platforms where read() returns
      partial results on small file reads.
    - Don't rebuild the entire router store every time we get 32K of
      routers: rebuild it when the journal gets very large, or when
      the gaps in the store get very large.

  o Minor features:
    - When routers publish SVN revisions in their router descriptors,
      authorities now include those versions correctly in networkstatus
      documents.
    - Warn when using a version of libevent before 1.3b to run a server on
      OSX or BSD: these versions interact badly with userspace threads.


Changes in version 0.1.2.13 - 2007-04-24
  This release features some major anonymity fixes, such as safer path
  selection; better client performance; faster bootstrapping, better
  address detection, and better DNS support for servers; write limiting as
  well as read limiting to make servers easier to run; and a huge pile of
  other features and bug fixes. The bundles also ship with Vidalia 0.0.11.

  Tor 0.1.2.13 is released in memory of Rob Levin (1955-2006), aka lilo
  of the Freenode IRC network, remembering his patience and vision for
  free speech on the Internet.

  o Major features, client performance:
    - Weight directory requests by advertised bandwidth. Now we can
      let servers enable write limiting but still allow most clients to
      succeed at their directory requests. (We still ignore weights when
      choosing a directory authority; I hope this is a feature.)
    - Stop overloading exit nodes -- avoid choosing them for entry or
      middle hops when the total bandwidth available from non-exit nodes
      is much higher than the total bandwidth available from exit nodes.
    - Rather than waiting a fixed amount of time between retrying
      application connections, we wait only 10 seconds for the first,
      10 seconds for the second, and 15 seconds for each retry after
      that. Hopefully this will improve the expected user experience.
    - Sometimes we didn't bother sending a RELAY_END cell when an attempt
      to open a stream fails; now we do in more cases. This should
      make clients able to find a good exit faster in some cases, since
      unhandleable requests will now get an error rather than timing out.

  o Major features, client functionality:
    - Implement BEGIN_DIR cells, so we can connect to a directory
      server via TLS to do encrypted directory requests rather than
      plaintext. Enable via the TunnelDirConns and PreferTunneledDirConns
      config options if you like. For now, this feature only works if
      you already have a descriptor for the destination dirserver.
    - Add support for transparent application connections: this basically
      bundles the functionality of trans-proxy-tor into the Tor
      mainline. Now hosts with compliant pf/netfilter implementations
      can redirect TCP connections straight to Tor without diverting
      through SOCKS. (Based on patch from tup.)
    - Add support for using natd; this allows FreeBSDs earlier than
      5.1.2 to have ipfw send connections through Tor without using
      SOCKS. (Patch from Zajcev Evgeny with tweaks from tup.)

  o Major features, servers:
    - Setting up a dyndns name for your server is now optional: servers
      with no hostname or IP address will learn their IP address by
      asking the directory authorities. This code only kicks in when you
      would normally have exited with a "no address" error. Nothing's
      authenticated, so use with care.
    - Directory servers now spool server descriptors, v1 directories,
      and v2 networkstatus objects to buffers as needed rather than en
      masse. They also mmap the cached-routers files. These steps save
      lots of memory.
    - Stop requiring clients to have well-formed certificates, and stop
      checking nicknames in certificates. (Clients have certificates so
      that they can look like Tor servers, but in the future we might want
      to allow them to look like regular TLS clients instead. Nicknames
      in certificates serve no purpose other than making our protocol
      easier to recognize on the wire.) Implements proposal 106.

  o Improvements on DNS support:
    - Add "eventdns" asynchronous dns library originally based on code
      from Adam Langley. Now we can discard the old rickety dnsworker
      concept, and support a wider variety of DNS functions. Allows
      multithreaded builds on NetBSD and OpenBSD again.
    - Add server-side support for "reverse" DNS lookups (using PTR
      records so clients can determine the canonical hostname for a given
      IPv4 address). Only supported by servers using eventdns; servers
      now announce in their descriptors if they don't support eventdns.
    - Workaround for name servers (like Earthlink's) that hijack failing
      DNS requests and replace the no-such-server answer with a "helpful"
      redirect to an advertising-driven search portal. Also work around
      DNS hijackers who "helpfully" decline to hijack known-invalid
      RFC2606 addresses. Config option "ServerDNSDetectHijacking 0"
      lets you turn it off.
    - Servers now check for the case when common DNS requests are going to
      wildcarded addresses (i.e. all getting the same answer), and change
      their exit policy to reject *:* if it's happening.
    - When asked to resolve a hostname, don't use non-exit servers unless
      requested to do so. This allows servers with broken DNS to be
      useful to the network.
    - Start passing "ipv4" hints to getaddrinfo(), so servers don't do
      useless IPv6 DNS resolves.
    - Specify and implement client-side SOCKS5 interface for reverse DNS
      lookups (see doc/socks-extensions.txt). Also cache them.
    - When we change nameservers or IP addresses, reset and re-launch
      our tests for DNS hijacking.

  o Improvements on reachability testing:
    - Servers send out a burst of long-range padding cells once they've
      established that they're reachable. Spread them over 4 circuits,
      so hopefully a few will be fast. This exercises bandwidth and
      bootstraps them into the directory more quickly.
    - When we find our DirPort to be reachable, publish a new descriptor
      so we'll tell the world (reported by pnx).
    - Directory authorities now only decide that routers are reachable
      if their identity keys are as expected.
    - Do DirPort reachability tests less often, since a single test
      chews through many circuits before giving up.
    - Avoid some false positives during reachability testing: don't try
      to test via a server that's on the same /24 network as us.
    - Start publishing one minute or so after we find our ORPort
      to be reachable. This will help reduce the number of descriptors
      we have for ourselves floating around, since it's quite likely
      other things (e.g. DirPort) will change during that minute too.
    - Routers no longer try to rebuild long-term connections to directory
      authorities, and directory authorities no longer try to rebuild
      long-term connections to all servers. We still don't hang up
      connections in these two cases though -- we need to look at it
      more carefully to avoid flapping, and we likely need to wait til
      0.1.1.x is obsolete.

  o Improvements on rate limiting:
    - Enable write limiting as well as read limiting. Now we sacrifice
      capacity if we're pushing out lots of directory traffic, rather
      than overrunning the user's intended bandwidth limits.
    - Include TLS overhead when counting bandwidth usage; previously, we
      would count only the bytes sent over TLS, but not the bytes used
      to send them.
    - Servers decline directory requests much more aggressively when
      they're low on bandwidth. Otherwise they end up queueing more and
      more directory responses, which can't be good for latency.
    - But never refuse directory requests from local addresses.
    - Be willing to read or write on local connections (e.g. controller
      connections) even when the global rate limiting buckets are empty.
    - Flush local controller connection buffers periodically as we're
      writing to them, so we avoid queueing 4+ megabytes of data before
      trying to flush.
    - Revise and clean up the torrc.sample that we ship with; add
      a section for BandwidthRate and BandwidthBurst.

  o Major features, NT services:
    - Install as NT_AUTHORITY\LocalService rather than as SYSTEM; add a
      command-line flag so that admins can override the default by saying
      "tor --service install --user "SomeUser"". This will not affect
      existing installed services. Also, warn the user that the service
      will look for its configuration file in the service user's
      %appdata% directory. (We can't do the "hardwire the user's appdata
      directory" trick any more, since we may not have read access to that
      directory.)
    - Support running the Tor service with a torrc not in the same
      directory as tor.exe and default to using the torrc located in
      the %appdata%\Tor\ of the user who installed the service. Patch
      from Matt Edman.
    - Add an --ignore-missing-torrc command-line option so that we can
      get the "use sensible defaults if the configuration file doesn't
      exist" behavior even when specifying a torrc location on the
      command line.
    - When stopping an NT service, wait up to 10 sec for it to actually
      stop. (Patch from Matt Edman; resolves bug 295.)

  o Directory authority improvements:
    - Stop letting hibernating or obsolete servers affect uptime and
      bandwidth cutoffs.
    - Stop listing hibernating servers in the v1 directory.
    - Authorities no longer recommend exits as guards if this would shift
      too much load to the exit nodes.
    - Authorities now specify server versions in networkstatus. This adds
      about 2% to the size of compressed networkstatus docs, and allows
      clients to tell which servers support BEGIN_DIR and which don't.
      The implementation is forward-compatible with a proposed future
      protocol version scheme not tied to Tor versions.
    - DirServer configuration lines now have an orport= option so
      clients can open encrypted tunnels to the authorities without
      having downloaded their descriptors yet. Enabled for moria1,
      moria2, tor26, and lefkada now in the default configuration.
    - Add a BadDirectory flag to network status docs so that authorities
      can (eventually) tell clients about caches they believe to be
      broken. Not used yet.
    - Allow authorities to list nodes as bad exits in their
      approved-routers file by fingerprint or by address. If most
      authorities set a BadExit flag for a server, clients don't think
      of it as a general-purpose exit. Clients only consider authorities
      that advertise themselves as listing bad exits.
    - Patch from Steve Hildrey: Generate network status correctly on
      non-versioning dirservers.
    - Have directory authorities allow larger amounts of drift in uptime
      without replacing the server descriptor: previously, a server that
      restarted every 30 minutes could have 48 "interesting" descriptors
      per day.
    - Reserve the nickname "Unnamed" for routers that can't pick
      a hostname: any router can call itself Unnamed; directory
      authorities will never allocate Unnamed to any particular router;
      clients won't believe that any router is the canonical Unnamed.

  o Directory mirrors and clients:
    - Discard any v1 directory info that's over 1 month old (for
      directories) or over 1 week old (for running-routers lists).
    - Clients track responses with status 503 from dirservers. After a
      dirserver has given us a 503, we try not to use it until an hour has
      gone by, or until we have no dirservers that haven't given us a 503.
    - When we get a 503 from a directory, and we're not a server, we no
      longer count the failure against the total number of failures
      allowed for the object we're trying to download.
    - Prepare for servers to publish descriptors less often: never
      discard a descriptor simply for being too old until either it is
      recommended by no authorities, or until we get a better one for
      the same router. Make caches consider retaining old recommended
      routers for even longer.
    - Directory servers now provide 'Pragma: no-cache' and 'Expires'
      headers for content, so that we can work better in the presence of
      caching HTTP proxies.
    - Stop fetching descriptors if you're not a dir mirror and you
      haven't tried to establish any circuits lately. (This currently
      causes some dangerous behavior, because when you start up again
      you'll use your ancient server descriptors.)

  o Major fixes, crashes:
    - Stop crashing when the controller asks us to resetconf more than
      one config option at once. (Vidalia 0.0.11 does this.)
    - Fix a longstanding obscure crash bug that could occur when we run
      out of DNS worker processes, if we're not using eventdns. (Resolves
      bug 390.)
    - Fix an assert that could trigger if a controller quickly set then
      cleared EntryNodes. (Bug found by Udo van den Heuvel.)
    - Avoid crash when telling controller about stream-status and a
      stream is detached.
    - Avoid sending junk to controllers or segfaulting when a controller
      uses EVENT_NEW_DESC with verbose nicknames.
    - Stop triggering asserts if the controller tries to extend hidden
      service circuits (reported by mwenge).
    - If we start a server with ClientOnly 1, then set ClientOnly to 0
      and hup, stop triggering an assert based on an empty onion_key.
    - Mask out all signals in sub-threads; only the libevent signal
      handler should be processing them. This should prevent some crashes
      on some machines using pthreads. (Patch from coderman.)
    - Disable kqueue on OS X 10.3 and earlier, to fix bug 371.

  o Major fixes, anonymity/security:
    - Automatically avoid picking more than one node from the same
      /16 network when constructing a circuit. Add an
      "EnforceDistinctSubnets" option to let people disable it if they
      want to operate private test networks on a single subnet.
    - When generating bandwidth history, round down to the nearest
      1k. When storing accounting data, round up to the nearest 1k.
    - When we're running as a server, remember when we last rotated onion
      keys, so that we will rotate keys once they're a week old even if
      we never stay up for a week ourselves.
    - If a client asked for a server by name, and there's a named server
      in our network-status but we don't have its descriptor yet, we
      could return an unnamed server instead.
    - Reject (most) attempts to use Tor circuits with length one. (If
      many people start using Tor as a one-hop proxy, exit nodes become
      a more attractive target for compromise.)
    - Just because your DirPort is open doesn't mean people should be
      able to remotely teach you about hidden service descriptors. Now
      only accept rendezvous posts if you've got HSAuthoritativeDir set.
    - Fix a potential race condition in the rpm installer. Found by
      Stefan Nordhausen.
    - Do not log IPs with TLS failures for incoming TLS
      connections. (Fixes bug 382.)

  o Major fixes, other:
    - If our system clock jumps back in time, don't publish a negative
      uptime in the descriptor.
    - When we start during an accounting interval before it's time to wake
      up, remember to wake up at the correct time. (May fix bug 342.)
    - Previously, we would cache up to 16 old networkstatus documents
      indefinitely, if they came from nontrusted authorities. Now we
      discard them if they are more than 10 days old.
    - When we have a state file we cannot parse, tell the user and
      move it aside. Now we avoid situations where the user starts
      Tor in 1904, Tor writes a state file with that timestamp in it,
      the user fixes her clock, and Tor refuses to start.
    - Publish a new descriptor after we hup/reload. This is important
      if our config has changed such that we'll want to start advertising
      our DirPort now, etc.
    - If we are using an exit enclave and we can't connect, e.g. because
      its webserver is misconfigured to not listen on localhost, then
      back off and try connecting from somewhere else before we fail.

  o New config options or behaviors:
    - When EntryNodes are configured, rebuild the guard list to contain,
      in order: the EntryNodes that were guards before; the rest of the
      EntryNodes; the nodes that were guards before.
    - Do not warn when individual nodes in the configuration's EntryNodes,
      ExitNodes, etc are down: warn only when all possible nodes
      are down. (Fixes bug 348.)
    - Put a lower-bound on MaxAdvertisedBandwidth.
    - Start using the state file to store bandwidth accounting data:
      the bw_accounting file is now obsolete. We'll keep generating it
      for a while for people who are still using 0.1.2.4-alpha.
    - Try to batch changes to the state file so that we do as few
      disk writes as possible while still storing important things in
      a timely fashion.
    - The state file and the bw_accounting file get saved less often when
      the AvoidDiskWrites config option is set.
    - Make PIDFile work on Windows.
    - Add internal descriptions for a bunch of configuration options:
      accessible via controller interface and in comments in saved
      options files.
    - Reject *:563 (NNTPS) in the default exit policy. We already reject
      NNTP by default, so this seems like a sensible addition.
    - Clients now reject hostnames with invalid characters. This should
      avoid some inadvertent info leaks. Add an option
      AllowNonRFC953Hostnames to disable this behavior, in case somebody
      is running a private network with hosts called @, !, and #.
    - Check for addresses with invalid characters at the exit as well,
      and warn less verbosely when they fail. You can override this by
      setting ServerDNSAllowNonRFC953Addresses to 1.
    - Remove some options that have been deprecated since at least
      0.1.0.x: AccountingMaxKB, LogFile, DebugLogFile, LogLevel, and
      SysLog. Use AccountingMax instead of AccountingMaxKB, and use Log
      to set log options. Mark PathlenCoinWeight as obsolete.
    - Stop accepting certain malformed ports in configured exit policies.
    - When the user uses bad syntax in the Log config line, stop
      suggesting other bad syntax as a replacement.
    - Add new config option "ResolvConf" to let the server operator
      choose an alternate resolve.conf file when using eventdns.
    - If one of our entry guards is on the ExcludeNodes list, or the
      directory authorities don't think it's a good guard, treat it as
      if it were unlisted: stop using it as a guard, and throw it off
      the guards list if it stays that way for a long time.
    - Allow directory authorities to be marked separately as authorities
      for the v1 directory protocol, the v2 directory protocol, and
      as hidden service directories, to make it easier to retire old
      authorities. V1 authorities should set "HSAuthoritativeDir 1"
      to continue being hidden service authorities too.
    - Remove 8888 as a LongLivedPort, and add 6697 (IRCS).
    - Make TrackExitHosts case-insensitive, and fix the behavior of
      ".suffix" TrackExitHosts items to avoid matching in the middle of
      an address.
    - New DirPort behavior: if you have your dirport set, you download
      descriptors aggressively like a directory mirror, whether or not
      your ORPort is set.

  o Docs:
    - Create a new file ReleaseNotes which was the old ChangeLog. The
      new ChangeLog file now includes the notes for all development
      versions too.
    - Add a new address-spec.txt document to describe our special-case
      addresses: .exit, .onion, and .noconnnect.
    - Fork the v1 directory protocol into its own spec document,
      and mark dir-spec.txt as the currently correct (v2) spec.

  o Packaging, porting, and contrib
    - "tor --verify-config" now exits with -1(255) or 0 depending on
      whether the config options are bad or good.
    - The Debian package now uses --verify-config when (re)starting,
      to distinguish configuration errors from other errors.
    - Adapt a patch from goodell to let the contrib/exitlist script
      take arguments rather than require direct editing.
    - Prevent the contrib/exitlist script from printing the same
      result more than once.
    - Add support to tor-resolve tool for reverse lookups and SOCKS5.
    - In the hidden service example in torrc.sample, stop recommending
      esoteric and discouraged hidden service options.
    - Patch from Michael Mohr to contrib/cross.sh, so it checks more
      values before failing, and always enables eventdns.
    - Try to detect Windows correctly when cross-compiling.
    - Libevent-1.2 exports, but does not define in its headers, strlcpy.
      Try to fix this in configure.in by checking for most functions
      before we check for libevent.
    - Update RPMs to require libevent 1.2.
    - Experimentally re-enable kqueue on OSX when using libevent 1.1b
      or later. Log when we are doing this, so we can diagnose it when
      it fails. (Also, recommend libevent 1.1b for kqueue and
      win32 methods; deprecate libevent 1.0b harder; make libevent
      recommendation system saner.)
    - Build with recent (1.3+) libevents on platforms that do not
      define the nonstandard types "u_int8_t" and friends.
    - Remove architecture from OS X builds. The official builds are
      now universal binaries.
    - Run correctly on OS X platforms with case-sensitive filesystems.
    - Correctly set maximum connection limit on Cygwin. (This time
      for sure!)
    - Start compiling on MinGW on Windows (patches from Mike Chiussi
      and many others).
    - Start compiling on MSVC6 on Windows (patches from Frediano Ziglio).
    - Finally fix the openssl warnings from newer gccs that believe that
      ignoring a return value is okay, but casting a return value and
      then ignoring it is a sign of madness.
    - On architectures where sizeof(int)>4, still clamp declarable
      bandwidth to INT32_MAX.

  o Minor features, controller:
    - Warn the user when an application uses the obsolete binary v0
      control protocol. We're planning to remove support for it during
      the next development series, so it's good to give people some
      advance warning.
    - Add STREAM_BW events to report per-entry-stream bandwidth
      use. (Patch from Robert Hogan.)
    - Rate-limit SIGNEWNYM signals in response to controllers that
      impolitely generate them for every single stream. (Patch from
      mwenge; closes bug 394.)
    - Add a REMAP status to stream events to note that a stream's
      address has changed because of a cached address or a MapAddress
      directive.
    - Make REMAP stream events have a SOURCE (cache or exit), and
      make them generated in every case where we get a successful
      connected or resolved cell.
    - Track reasons for OR connection failure; make these reasons
      available via the controller interface. (Patch from Mike Perry.)
    - Add a SOCKS_BAD_HOSTNAME client status event so controllers
      can learn when clients are sending malformed hostnames to Tor.
    - Specify and implement some of the controller status events.
    - Have GETINFO dir/status/* work on hosts with DirPort disabled.
    - Reimplement GETINFO so that info/names stays in sync with the
      actual keys.
    - Implement "GETINFO fingerprint".
    - Implement "SETEVENTS GUARD" so controllers can get updates on
      entry guard status as it changes.
    - Make all connections to addresses of the form ".noconnect"
      immediately get closed. This lets application/controller combos
      successfully test whether they're talking to the same Tor by
      watching for STREAM events.
    - Add a REASON field to CIRC events; for backward compatibility, this
      field is sent only to controllers that have enabled the extended
      event format. Also, add additional reason codes to explain why
      a given circuit has been destroyed or truncated. (Patches from
      Mike Perry)
    - Add a REMOTE_REASON field to extended CIRC events to tell the
      controller why a remote OR told us to close a circuit.
    - Stream events also now have REASON and REMOTE_REASON fields,
      working much like those for circuit events.
    - There's now a GETINFO ns/... field so that controllers can ask Tor
      about the current status of a router.
    - A new event type "NS" to inform a controller when our opinion of
      a router's status has changed.
    - Add a GETINFO events/names and GETINFO features/names so controllers
      can tell which events and features are supported.
    - A new CLEARDNSCACHE signal to allow controllers to clear the
      client-side DNS cache without expiring circuits.
    - Fix CIRC controller events so that controllers can learn the
      identity digests of non-Named servers used in circuit paths.
    - Let controllers ask for more useful identifiers for servers. Instead
      of learning identity digests for un-Named servers and nicknames
      for Named servers, the new identifiers include digest, nickname,
      and indication of Named status. Off by default; see control-spec.txt
      for more information.
    - Add a "getinfo address" controller command so it can display Tor's
      best guess to the user.
    - New controller event to alert the controller when our server
      descriptor has changed.
    - Give more meaningful errors on controller authentication failure.
    - Export the default exit policy via the control port, so controllers
      don't need to guess what it is / will be later.

  o Minor bugfixes, controller:
    - When creating a circuit via the controller, send a 'launched'
      event when we're done, so we follow the spec better.
    - Correct the control spec to match how the code actually responds
      to 'getinfo addr-mappings/*'. Reported by daejees.
    - The control spec described a GUARDS event, but the code
      implemented a GUARD event. Standardize on GUARD, but let people
      ask for GUARDS too. Reported by daejees.
    - Give the controller END_STREAM_REASON_DESTROY events _before_ we
      clear the corresponding on_circuit variable, and remember later
      that we don't need to send a redundant CLOSED event. (Resolves part
      3 of bug 367.)
    - Report events where a resolve succeeded or where we got a socks
      protocol error correctly, rather than calling both of them
      "INTERNAL".
    - Change reported stream target addresses to IP consistently when
      we finally get the IP from an exit node.
    - Send log messages to the controller even if they happen to be very
      long.
    - Flush ERR-level controller status events just like we currently
      flush ERR-level log events, so that a Tor shutdown doesn't prevent
      the controller from learning about current events.
    - Report the circuit number correctly in STREAM CLOSED events. Bug
      reported by Mike Perry.
    - Do not report bizarre values for results of accounting GETINFOs
      when the last second's write or read exceeds the allotted bandwidth.
    - Report "unrecognized key" rather than an empty string when the
      controller tries to fetch a networkstatus that doesn't exist.
    - When the controller does a "GETINFO network-status", tell it
      about even those routers whose descriptors are very old, and use
      long nicknames where appropriate.
    - Fix handling of verbose nicknames with ORCONN controller events:
      make them show up exactly when requested, rather than exactly when
      not requested.
    - Controller signals now work on non-Unix platforms that don't define
      SIGUSR1 and SIGUSR2 the way we expect.
    - Respond to SIGNAL command before we execute the signal, in case
      the signal shuts us down. Suggested by Karsten Loesing.
    - Handle reporting OR_CONN_EVENT_NEW events to the controller.

  o Minor features, code performance:
    - Major performance improvement on inserting descriptors: change
      algorithm from O(n^2) to O(n).
    - Do not rotate onion key immediately after setting it for the first
      time.
    - Call router_have_min_dir_info half as often. (This is showing up in
      some profiles, but not others.)
    - When using GCC, make log_debug never get called at all, and its
      arguments never get evaluated, when no debug logs are configured.
      (This is showing up in some profiles, but not others.)
    - Statistics dumped by -USR2 now include a breakdown of public key
      operations, for profiling.
    - Make the common memory allocation path faster on machines where
      malloc(0) returns a pointer.
    - Split circuit_t into origin_circuit_t and or_circuit_t, and
      split connection_t into edge, or, dir, control, and base structs.
      These will save quite a bit of memory on busy servers, and they'll
      also help us track down bugs in the code and bugs in the spec.
    - Use OpenSSL's AES implementation on platforms where it's faster.
      This could save us as much as 10% CPU usage.

  o Minor features, descriptors and descriptor handling:
    - Avoid duplicate entries on MyFamily line in server descriptor.
    - When Tor receives a router descriptor that it asked for, but
      no longer wants (because it has received fresh networkstatuses
      in the meantime), do not warn the user. Cache the descriptor if
      we're a cache; drop it if we aren't.
    - Servers no longer ever list themselves in their "family" line,
      even if configured to do so. This makes it easier to configure
      family lists conveniently.

  o Minor fixes, confusing/misleading log messages:
    - Display correct results when reporting which versions are
      recommended, and how recommended they are. (Resolves bug 383.)
    - Inform the server operator when we decide not to advertise a
      DirPort due to AccountingMax enabled or a low BandwidthRate.
    - Only include function names in log messages for info/debug messages.
      For notice/warn/err, the content of the message should be clear on
      its own, and printing the function name only confuses users.
    - Remove even more protocol-related warnings from Tor server logs,
      such as bad TLS handshakes and malformed begin cells.
    - Fix bug 314: Tor clients issued "unsafe socks" warnings even
      when the IP address is mapped through MapAddress to a hostname.
    - Fix misleading log messages: an entry guard that is "unlisted",
      as well as not known to be "down" (because we've never heard
      of it), is not therefore "up".

  o Minor fixes, old/obsolete behavior:
    - Start assuming we can use a create_fast cell if we don't know
      what version a router is running.
    - We no longer look for identity and onion keys in "identity.key" and
      "onion.key" -- these were replaced by secret_id_key and
      secret_onion_key in 0.0.8pre1.
    - We no longer require unrecognized directory entries to be
      preceded by "opt".
    - Drop compatibility with obsolete Tors that permit create cells
      to have the wrong circ_id_type.
    - Remove code to special-case "-cvs" ending, since it has not
      actually mattered since 0.0.9.
    - Don't re-write the fingerprint file every restart, unless it has
      changed.

  o Minor fixes, misc client-side behavior:
    - Always remove expired routers and networkstatus docs before checking
      whether we have enough information to build circuits. (Fixes
      bug 373.)
    - When computing clock skew from directory HTTP headers, consider what
      time it was when we finished asking for the directory, not what
      time it is now.
    - Make our socks5 handling more robust to broken socks clients:
      throw out everything waiting on the buffer in between socks
      handshake phases, since they can't possibly (so the theory
      goes) have predicted what we plan to respond to them.
    - Expire socks connections if they spend too long waiting for the
      handshake to finish. Previously we would let them sit around for
      days, if the connecting application didn't close them either.
    - And if the socks handshake hasn't started, don't send a
      "DNS resolve socks failed" handshake reply; just close it.
    - If the user asks to use invalid exit nodes, be willing to use
      unstable ones.
    - Track unreachable entry guards correctly: don't conflate
      'unreachable by us right now' with 'listed as down by the directory
      authorities'. With the old code, if a guard was unreachable by us
      but listed as running, it would clog our guard list forever.
    - Behave correctly in case we ever have a network with more than
      2GB/s total advertised capacity.
    - Claim a commonname of Tor, rather than TOR, in TLS handshakes.
    - Fix a memory leak when we ask for "all" networkstatuses and we
      get one we don't recognize.


Changes in version 0.1.1.26 - 2006-12-14
  o Security bugfixes:
    - Stop sending the HttpProxyAuthenticator string to directory
      servers when directory connections are tunnelled through Tor.
    - Clients no longer store bandwidth history in the state file.
    - Do not log introduction points for hidden services if SafeLogging
      is set.

  o Minor bugfixes:
    - Fix an assert failure when a directory authority sets
      AuthDirRejectUnlisted and then receives a descriptor from an
      unlisted router (reported by seeess).


Changes in version 0.1.1.25 - 2006-11-04
  o Major bugfixes:
    - When a client asks us to resolve (rather than connect to)
      an address, and we have a cached answer, give them the cached
      answer. Previously, we would give them no answer at all.
    - We were building exactly the wrong circuits when we predict
      hidden service requirements, meaning Tor would have to build all
      its circuits on demand.
    - If none of our live entry guards have a high uptime, but we
      require a guard with a high uptime, try adding a new guard before
      we give up on the requirement. This patch should make long-lived
      connections more stable on average.
    - When testing reachability of our DirPort, don't launch new
      tests when there's already one in progress -- unreachable
      servers were stacking up dozens of testing streams.

  o Security bugfixes:
    - When the user sends a NEWNYM signal, clear the client-side DNS
      cache too. Otherwise we continue to act on previous information.

  o Minor bugfixes:
    - Avoid a memory corruption bug when creating a hash table for
      the first time.
    - Avoid possibility of controller-triggered crash when misusing
      certain commands from a v0 controller on platforms that do not
      handle printf("%s",NULL) gracefully.
    - Avoid infinite loop on unexpected controller input.
    - Don't log spurious warnings when we see a circuit close reason we
      don't recognize; it's probably just from a newer version of Tor.
    - Add Vidalia to the OS X uninstaller script, so when we uninstall
      Tor/Privoxy we also uninstall Vidalia.


Changes in version 0.1.1.24 - 2006-09-29
  o Major bugfixes:
    - Allow really slow clients to not hang up five minutes into their
      directory downloads (suggested by Adam J. Richter).
    - Fix major performance regression from 0.1.0.x: instead of checking
      whether we have enough directory information every time we want to
      do something, only check when the directory information has changed.
      This should improve client CPU usage by 25-50%.
    - Don't crash if, after a server has been running for a while,
      it can't resolve its hostname.
    - When a client asks us to resolve (not connect to) an address,
      and we have a cached answer, give them the cached answer.
      Previously, we would give them no answer at all.

  o Minor bugfixes:
    - Allow Tor to start when RunAsDaemon is set but no logs are set.
    - Don't crash when the controller receives a third argument to an
      "extendcircuit" request.
    - Controller protocol fixes: fix encoding in "getinfo addr-mappings"
      response; fix error code when "getinfo dir/status/" fails.
    - Fix configure.in to not produce broken configure files with
      more recent versions of autoconf. Thanks to Clint for his auto*
      voodoo.
    - Fix security bug on NetBSD that could allow someone to force
      uninitialized RAM to be sent to a server's DNS resolver. This
      only affects NetBSD and other platforms that do not bounds-check
      tolower().
    - Warn user when using libevent 1.1a or earlier with win32 or kqueue
      methods: these are known to be buggy.
    - If we're a directory mirror and we ask for "all" network status
      documents, we would discard status documents from authorities
      we don't recognize.


Changes in version 0.1.1.23 - 2006-07-30
  o Major bugfixes:
    - Fast Tor servers, especially exit nodes, were triggering asserts
      due to a bug in handling the list of pending DNS resolves. Some
      bugs still remain here; we're hunting them.
    - Entry guards could crash clients by sending unexpected input.
    - More fixes on reachability testing: if you find yourself reachable,
      then don't ever make any client requests (so you stop predicting
      circuits), then hup or have your clock jump, then later your IP
      changes, you won't think circuits are working, so you won't try to
      test reachability, so you won't publish.

  o Minor bugfixes:
    - Avoid a crash if the controller does a resetconf firewallports
      and then a setconf fascistfirewall=1.
    - Avoid an integer underflow when the dir authority decides whether
      a router is stable: we might wrongly label it stable, and compute
      a slightly wrong median stability, when a descriptor is published
      later than now.
    - Fix a place where we might trigger an assert if we can't build our
      own server descriptor yet.


Changes in version 0.1.1.22 - 2006-07-05
  o Major bugfixes:
    - Fix a big bug that was causing servers to not find themselves
      reachable if they changed IP addresses. Since only 0.1.1.22+
      servers can do reachability testing correctly, now we automatically
      make sure to test via one of these.
    - Fix to allow clients and mirrors to learn directory info from
      descriptor downloads that get cut off partway through.
    - Directory authorities had a bug in deciding if a newly published
      descriptor was novel enough to make everybody want a copy -- a few
      servers seem to be publishing new descriptors many times a minute.
  o Minor bugfixes:
    - Fix a rare bug that was causing some servers to complain about
      "closing wedged cpuworkers" and skip some circuit create requests.
    - Make the Exit flag in directory status documents actually work.


Changes in version 0.1.1.21 - 2006-06-10
  o Crash and assert fixes from 0.1.1.20:
    - Fix a rare crash on Tor servers that have enabled hibernation.
    - Fix a seg fault on startup for Tor networks that use only one
      directory authority.
    - Fix an assert from a race condition that occurs on Tor servers
      while exiting, where various threads are trying to log that they're
      exiting, and delete the logs, at the same time.
    - Make our unit tests pass again on certain obscure platforms.

  o Other fixes:
    - Add support for building SUSE RPM packages.
    - Speed up initial bootstrapping for clients: if we are making our
      first ever connection to any entry guard, then don't mark it down
      right after that.
    - When only one Tor server in the network is labelled as a guard,
      and we've already picked him, we would cycle endlessly picking him
      again, being unhappy about it, etc. Now we specifically exclude
      current guards when picking a new guard.
    - Servers send create cells more reliably after the TLS connection
      is established: we were sometimes forgetting to send half of them
      when we had more than one pending.
    - If we get a create cell that asks us to extend somewhere, but the
      Tor server there doesn't match the expected digest, we now send
      a destroy cell back, rather than silently doing nothing.
    - Make options->RedirectExit work again.
    - Make cookie authentication for the controller work again.
    - Stop being picky about unusual characters in the arguments to
      mapaddress. It's none of our business.
    - Add a new config option "TestVia" that lets you specify preferred
      middle hops to use for test circuits. Perhaps this will let me
      debug the reachability problems better.

  o Log / documentation fixes:
    - If we're a server and some peer has a broken TLS certificate, don't
      log about it unless ProtocolWarnings is set, i.e., we want to hear
      about protocol violations by others.
    - Fix spelling of VirtualAddrNetwork in man page.
    - Add a better explanation at the top of the autogenerated torrc file
      about what happened to our old torrc.


Changes in version 0.1.1.20 - 2006-05-23
  o Crash and assert fixes from 0.1.0.17:
    - Fix assert bug in close_logs() on exit: when we close and delete
      logs, remove them all from the global "logfiles" list.
    - Fix an assert error when we're out of space in the connection_list
      and we try to post a hidden service descriptor (reported by Peter
      Palfrader).
    - Fix a rare assert error when we've tried all intro points for
      a hidden service and we try fetching the service descriptor again:
      "Assertion conn->state != AP_CONN_STATE_RENDDESC_WAIT failed".
    - Setconf SocksListenAddress kills Tor if it fails to bind. Now back
      out and refuse the setconf if it would fail.
    - If you specify a relative torrc path and you set RunAsDaemon in
      your torrc, then it chdir()'s to the new directory. If you then
      HUP, it tries to load the new torrc location, fails, and exits.
      The fix: no longer allow a relative path to torrc when using -f.
    - Check for integer overflows in more places, when adding elements
      to smartlists. This could possibly prevent a buffer overflow
      on malicious huge inputs.

  o Security fixes, major:
    - When we're printing strings from the network, don't try to print
      non-printable characters. Now we're safer against shell escape
      sequence exploits, and also against attacks to fool users into
      misreading their logs.
    - Implement entry guards: automatically choose a handful of entry
      nodes and stick with them for all circuits. Only pick new guards
      when the ones you have are unsuitable, and if the old guards
      become suitable again, switch back. This will increase security
      dramatically against certain end-point attacks. The EntryNodes
      config option now provides some hints about which entry guards you
      want to use most; and StrictEntryNodes means to only use those.
      Fixes CVE-2006-0414.
    - Implement exit enclaves: if we know an IP address for the
      destination, and there's a running Tor server at that address
      which allows exit to the destination, then extend the circuit to
      that exit first. This provides end-to-end encryption and end-to-end
      authentication. Also, if the user wants a .exit address or enclave,
      use 4 hops rather than 3, and cannibalize a general circ for it
      if you can.
    - Obey our firewall options more faithfully:
      . If we can't get to a dirserver directly, try going via Tor.
      . Don't ever try to connect (as a client) to a place our
        firewall options forbid.
      . If we specify a proxy and also firewall options, obey the
        firewall options even when we're using the proxy: some proxies
        can only proxy to certain destinations.
    - Make clients regenerate their keys when their IP address changes.
    - For the OS X package's modified privoxy config file, comment
      out the "logfile" line so we don't log everything passed
      through privoxy.
    - Our TLS handshakes were generating a single public/private
      keypair for the TLS context, rather than making a new one for
      each new connection. Oops. (But we were still rotating them
      periodically, so it's not so bad.)
    - When we were cannibalizing a circuit with a particular exit
      node in mind, we weren't checking to see if that exit node was
      already present earlier in the circuit. Now we are.
    - Require server descriptors to list IPv4 addresses -- hostnames
      are no longer allowed. This also fixes potential vulnerabilities
      to servers providing hostnames as their address and then
      preferentially resolving them so they can partition users.
    - Our logic to decide if the OR we connected to was the right guy
      was brittle and maybe open to a mitm for invalid routers.

  o Security fixes, minor:
    - Adjust tor-spec.txt to parameterize cell and key lengths. Now
      Ian Goldberg can prove things about our handshake protocol more
      easily.
    - Make directory authorities generate a separate "guard" flag to
      mean "would make a good entry guard". Clients now honor the
      is_guard flag rather than looking at is_fast or is_stable.
    - Try to list MyFamily elements by key, not by nickname, and warn
      if we've not heard of a server.
    - Start using RAND_bytes rather than RAND_pseudo_bytes from
      OpenSSL. Also, reseed our entropy every hour, not just at
      startup. And add entropy in 512-bit chunks, not 160-bit chunks.
    - Refuse server descriptors where the fingerprint line doesn't match
      the included identity key. Tor doesn't care, but other apps (and
      humans) might actually be trusting the fingerprint line.
    - We used to kill the circuit when we receive a relay command we
      don't recognize. Now we just drop that cell.
    - Fix a bug found by Lasse Overlier: when we were making internal
      circuits (intended to be cannibalized later for rendezvous and
      introduction circuits), we were picking them so that they had
      useful exit nodes. There was no need for this, and it actually
      aids some statistical attacks.
    - Start treating internal circuits and exit circuits separately.
      It's important to keep them separate because internal circuits
      have their last hops picked like middle hops, rather than like
      exit hops. So exiting on them will break the user's expectations.
    - Fix a possible way to DoS dirservers.
    - When the client asked for a rendezvous port that the hidden
      service didn't want to provide, we were sending an IP address
      back along with the end cell. Fortunately, it was zero. But stop
      that anyway.

  o Packaging improvements:
    - Implement --with-libevent-dir option to ./configure. Improve
      search techniques to find libevent, and use those for openssl too.
    - Fix a couple of bugs in OpenSSL detection. Deal better when
      there are multiple SSLs installed with different versions.
    - Avoid warnings about machine/limits.h on Debian GNU/kFreeBSD.
    - On non-gcc compilers (e.g. Solaris's cc), use "-g -O" instead of
      "-Wall -g -O2".
    - Make unit tests (and other invocations that aren't the real Tor)
      run without launching listeners, creating subdirectories, and so on.
    - The OS X installer was adding a symlink for tor_resolve but
      the binary was called tor-resolve (reported by Thomas Hardly).
    - Now we can target arch and OS in rpm builds (contributed by
      Phobos). Also make the resulting dist-rpm filename match the
      target arch.
    - Apply Matt Ghali's --with-syslog-facility patch to ./configure
      if you log to syslog and want something other than LOG_DAEMON.
    - Fix the torify (tsocks) config file to not use Tor for localhost
      connections.
    - Start shipping socks-extensions.txt, tor-doc-unix.html,
      tor-doc-server.html, and stylesheet.css in the tarball.
    - Stop shipping tor-doc.html, INSTALL, and README in the tarball.
      They are useless now.
    - Add Peter Palfrader's contributed check-tor script. It lets you
      easily check whether a given server (referenced by nickname)
      is reachable by you.
    - Add BSD-style contributed startup script "rc.subr" from Peter
      Thoenen.

  o Directory improvements -- new directory protocol:
    - See tor/doc/dir-spec.txt for all the juicy details. Key points:
    - Authorities and caches publish individual descriptors (by
      digest, by fingerprint, by "all", and by "tell me yours").
    - Clients don't download or use the old directory anymore. Now they
      download network-statuses from the directory authorities, and
      fetch individual server descriptors as needed from mirrors.
    - Clients don't download descriptors of non-running servers.
    - Download descriptors by digest, not by fingerprint. Caches try to
      download all listed digests from authorities; clients try to
      download "best" digests from caches. This avoids partitioning
      and isolating attacks better.
    - Only upload a new server descriptor when options change, 18
      hours have passed, uptime is reset, or bandwidth changes a lot.
    - Directory authorities silently throw away new descriptors that
      haven't changed much if the timestamps are similar. We do this to
      tolerate older Tor servers that upload a new descriptor every 15
      minutes. (It seemed like a good idea at the time.)
    - Clients choose directory servers from the network status lists,
      not from their internal list of router descriptors. Now they can
      go to caches directly rather than needing to go to authorities
      to bootstrap the first set of descriptors.
    - When picking a random directory, prefer non-authorities if any
      are known.
    - Add a new flag to network-status indicating whether the server
      can answer v2 directory requests too.
    - Directory mirrors now cache up to 16 unrecognized network-status
      docs, so new directory authorities will be cached too.
    - Stop parsing, storing, or using running-routers output (but
      mirrors still cache and serve it).
    - Clients consider a threshold of "versioning" directory authorities
      before deciding whether to warn the user that he's obsolete.
    - Authorities publish separate sorted lists of recommended versions
      for clients and for servers.
    - Change DirServers config line to note which dirs are v1 authorities.
    - Put nicknames on the DirServer line, so we can refer to them
      without requiring all our users to memorize their IP addresses.
    - Remove option when getting directory cache to see whether they
      support running-routers; they all do now. Replace it with one
      to see whether caches support v2 stuff.
    - Stop listing down or invalid nodes in the v1 directory. This
      reduces its bulk by about 1/3, and reduces load on mirrors.
    - Mirrors no longer cache the v1 directory as often.
    - If we as a directory mirror don't know of any v1 directory
      authorities, then don't try to cache any v1 directories.

  o Other directory improvements:
    - Add lefkada.eecs.harvard.edu and tor.dizum.com as fourth and
      fifth authoritative directory servers.
    - Directory authorities no longer require an open connection from
      a server to consider him "reachable". We need this change because
      when we add new directory authorities, old servers won't know not
      to hang up on them.
    - Dir authorities now do their own external reachability testing
      of each server, and only list as running the ones they found to
      be reachable. We also send back warnings to the server's logs if
      it uploads a descriptor that we already believe is unreachable.
    - Spread the directory authorities' reachability testing over the
      entire testing interval, so we don't try to do 500 TLS's at once
      every 20 minutes.
    - Make the "stable" router flag in network-status be the median of
      the uptimes of running valid servers, and make clients pay
      attention to the network-status flags. Thus the cutoff adapts
      to the stability of the network as a whole, making IRC, IM, etc
      connections more reliable.
    - Make the v2 dir's "Fast" flag based on relative capacity, just
      like "Stable" is based on median uptime. Name everything in the
      top 7/8 Fast, and only the top 1/2 gets to be a Guard.
    - Retry directory requests if we fail to get an answer we like
      from a given dirserver (we were retrying before, but only if
      we fail to connect).
    - Return a robots.txt on our dirport to discourage google indexing.

  o Controller protocol improvements:
    - Revised controller protocol (version 1) that uses ascii rather
      than binary: tor/doc/control-spec.txt. Add supporting libraries
      in python and java and c# so you can use the controller from your
      applications without caring how our protocol works.
    - Allow the DEBUG controller event to work again. Mark certain log
      entries as "don't tell this to controllers", so we avoid cycles.
    - New controller function "getinfo accounting", to ask how
      many bytes we've used in this time period.
    - Add a "resetconf" command so you can set config options like
      AllowUnverifiedNodes and LongLivedPorts to "". Also, if you give
      a config option in the torrc with no value, then it clears it
      entirely (rather than setting it to its default).
    - Add a "getinfo config-file" to tell us where torrc is. Also
      expose guard nodes, config options/names.
    - Add a "quit" command (when when using the controller manually).
    - Add a new signal "newnym" to "change pseudonyms" -- that is, to
      stop using any currently-dirty circuits for new streams, so we
      don't link new actions to old actions. This also occurs on HUP
      or "signal reload".
    - If we would close a stream early (e.g. it asks for a .exit that
      we know would refuse it) but the LeaveStreamsUnattached config
      option is set by the controller, then don't close it.
    - Add a new controller event type "authdir_newdescs" that allows
      controllers to get all server descriptors that were uploaded to
      a router in its role as directory authority.
    - New controller option "getinfo desc/all-recent" to fetch the
      latest server descriptor for every router that Tor knows about.
    - Fix the controller's "attachstream 0" command to treat conn like
      it just connected, doing address remapping, handling .exit and
      .onion idioms, and so on. Now we're more uniform in making sure
      that the controller hears about new and closing connections.
    - Permit transitioning from ORPort==0 to ORPort!=0, and back, from
      the controller. Also, rotate dns and cpu workers if the controller
      changes options that will affect them; and initialize the dns
      worker cache tree whether or not we start out as a server.
    - Add a new circuit purpose 'controller' to let the controller ask
      for a circuit that Tor won't try to use. Extend the "extendcircuit"
      controller command to let you specify the purpose if you're starting
      a new circuit.  Add a new "setcircuitpurpose" controller command to
      let you change a circuit's purpose after it's been created.
    - Let the controller ask for "getinfo dir/server/foo" so it can ask
      directly rather than connecting to the dir port. "getinfo
      dir/status/foo" also works, but currently only if your DirPort
      is enabled.
    - Let the controller tell us about certain router descriptors
      that it doesn't want Tor to use in circuits. Implement
      "setrouterpurpose" and modify "+postdescriptor" to do this.
    - If the controller's *setconf commands fail, collect an error
      message in a string and hand it back to the controller -- don't
      just tell them to go read their logs.

  o Scalability, resource management, and performance:
    - Fix a major load balance bug: we were round-robin reading in 16 KB
      chunks, and servers with bandwidthrate of 20 KB, while downloading
      a 600 KB directory, would starve their other connections. Now we
      try to be a bit more fair.
    - Be more conservative about whether to advertise our DirPort.
      The main change is to not advertise if we're running at capacity
      and either a) we could hibernate ever or b) our capacity is low
      and we're using a default DirPort.
    - We weren't cannibalizing circuits correctly for
      CIRCUIT_PURPOSE_C_ESTABLISH_REND and
      CIRCUIT_PURPOSE_S_ESTABLISH_INTRO, so we were being forced to
      build those from scratch. This should make hidden services faster.
    - Predict required circuits better, with an eye toward making hidden
      services faster on the service end.
    - Compress exit policies even more: look for duplicate lines and
      remove them.
    - Generate 18.0.0.0/8 address policy format in descs when we can;
      warn when the mask is not reducible to a bit-prefix.
    - There used to be two ways to specify your listening ports in a
      server descriptor: on the "router" line and with a separate "ports"
      line. Remove support for the "ports" line.
    - Reduce memory requirements in our structs by changing the order
      of fields. Replace balanced trees with hash tables. Inline
      bottleneck smartlist functions. Add a "Map from digest to void*"
      abstraction so we can do less hex encoding/decoding, and use it
      in router_get_by_digest(). Many other CPU and memory improvements.
    - Allow tor_gzip_uncompress to extract as much as possible from
      truncated compressed data. Try to extract as many
      descriptors as possible from truncated http responses (when
      purpose is DIR_PURPOSE_FETCH_ROUTERDESC).
    - Make circ->onionskin a pointer, not a static array. moria2 was using
      125000 circuit_t's after it had been up for a few weeks, which
      translates to 20+ megs of wasted space.
    - The private half of our EDH handshake keys are now chosen out
      of 320 bits, not 1024 bits. (Suggested by Ian Goldberg.)
    - Stop doing the complex voodoo overkill checking for insecure
      Diffie-Hellman keys. Just check if it's in [2,p-2] and be happy.
    - Do round-robin writes for TLS of at most 16 kB per write. This
      might be more fair on loaded Tor servers.
    - Do not use unaligned memory access on alpha, mips, or mipsel.
      It *works*, but is very slow, so we treat them as if it doesn't.

  o Other bugfixes and improvements:
    - Start storing useful information to $DATADIR/state, so we can
      remember things across invocations of Tor. Retain unrecognized
      lines so we can be forward-compatible, and write a TorVersion line
      so we can be backward-compatible.
    - If ORPort is set, Address is not explicitly set, and our hostname
      resolves to a private IP address, try to use an interface address
      if it has a public address. Now Windows machines that think of
      themselves as localhost can guess their address.
    - Regenerate our local descriptor if it's dirty and we try to use
      it locally (e.g. if it changes during reachability detection).
      This was causing some Tor servers to keep publishing the same
      initial descriptor forever.
    - Tor servers with dynamic IP addresses were needing to wait 18
      hours before they could start doing reachability testing using
      the new IP address and ports. This is because they were using
      the internal descriptor to learn what to test, yet they were only
      rebuilding the descriptor once they decided they were reachable.
    - It turns out we couldn't bootstrap a network since we added
      reachability detection in 0.1.0.1-rc. Good thing the Tor network
      has never gone down. Add an AssumeReachable config option to let
      servers and authorities bootstrap. When we're trying to build a
      high-uptime or high-bandwidth circuit but there aren't enough
      suitable servers, try being less picky rather than simply failing.
    - Newly bootstrapped Tor networks couldn't establish hidden service
      circuits until they had nodes with high uptime. Be more tolerant.
    - Really busy servers were keeping enough circuits open on stable
      connections that they were wrapping around the circuit_id
      space. (It's only two bytes.) This exposed a bug where we would
      feel free to reuse a circuit_id even if it still exists but has
      been marked for close. Try to fix this bug. Some bug remains.
    - When we fail to bind or listen on an incoming or outgoing
      socket, we now close it before refusing, rather than just
      leaking it. (Thanks to Peter Palfrader for finding.)
    - Fix a file descriptor leak in start_daemon().
    - On Windows, you can't always reopen a port right after you've
      closed it. So change retry_listeners() to only close and re-open
      ports that have changed.
    - Workaround a problem with some http proxies that refuse GET
      requests that specify "Content-Length: 0". Reported by Adrian.
    - Recover better from TCP connections to Tor servers that are
      broken but don't tell you (it happens!); and rotate TLS
      connections once a week.
    - Fix a scary-looking but apparently harmless bug where circuits
      would sometimes start out in state CIRCUIT_STATE_OR_WAIT at
      servers, and never switch to state CIRCUIT_STATE_OPEN.
    - Check for even more Windows version flags when writing the platform
      string in server descriptors, and note any we don't recognize.
    - Add reasons to DESTROY and RELAY_TRUNCATED cells, so clients can
      get a better idea of why their circuits failed. Not used yet.
    - Add TTLs to RESOLVED, CONNECTED, and END_REASON_EXITPOLICY cells.
      We don't use them yet, but maybe one day our DNS resolver will be
      able to discover them.
    - Let people type "tor --install" as well as "tor -install" when they
      want to make it an NT service.
    - Looks like we were never delivering deflated (i.e. compressed)
      running-routers lists, even when asked. Oops.
    - We were leaking some memory every time the client changed IPs.
    - Clean up more of the OpenSSL memory when exiting, so we can detect
      memory leaks better.
    - Never call free() on tor_malloc()d memory. This will help us
      use dmalloc to detect memory leaks.
    - Some Tor servers process billions of cells per day. These
      statistics are now uint64_t's.
    - Check [X-]Forwarded-For headers in HTTP requests when generating
      log messages. This lets people run dirservers (and caches) behind
      Apache but still know which IP addresses are causing warnings.
    - Fix minor integer overflow in calculating when we expect to use up
      our bandwidth allocation before hibernating.
    - Lower the minimum required number of file descriptors to 1000,
      so we can have some overhead for Valgrind on Linux, where the
      default ulimit -n is 1024.
    - Stop writing the "router.desc" file, ever. Nothing uses it anymore,
      and its existence is confusing some users.

  o Config option fixes:
    - Add a new config option ExitPolicyRejectPrivate which defaults
      to on. Now all exit policies will begin with rejecting private
      addresses, unless the server operator explicitly turns it off.
    - Bump the default bandwidthrate to 3 MB, and burst to 6 MB.
    - Add new ReachableORAddresses and ReachableDirAddresses options
      that understand address policies. FascistFirewall is now a synonym
      for "ReachableORAddresses *:443", "ReachableDirAddresses *:80".
    - Start calling it FooListenAddress rather than FooBindAddress,
      since few of our users know what it means to bind an address
      or port.
    - If the user gave Tor an odd number of command-line arguments,
      we were silently ignoring the last one. Now we complain and fail.
      This wins the oldest-bug prize -- this bug has been present since
      November 2002, as released in Tor 0.0.0.
    - If you write "HiddenServicePort 6667 127.0.0.1 6668" in your
      torrc rather than "HiddenServicePort 6667 127.0.0.1:6668",
      it would silently ignore the 6668.
    - If we get a linelist or linelist_s config option from the torrc,
      e.g. ExitPolicy, and it has no value, warn and skip rather than
      silently resetting it to its default.
    - Setconf was appending items to linelists, not clearing them.
    - Add MyFamily to torrc.sample in the server section, so operators
      will be more likely to learn that it exists.
    - Make ContactInfo mandatory for authoritative directory servers.
    - MaxConn has been obsolete for a while now. Document the ConnLimit
      config option, which is a *minimum* number of file descriptors
      that must be available else Tor refuses to start.
    - Get rid of IgnoreVersion undocumented config option, and make us
      only warn, never exit, when we're running an obsolete version.
    - Make MonthlyAccountingStart config option truly obsolete now.
    - Correct the man page entry on TrackHostExitsExpire.
    - Let directory authorities start even if they don't specify an
      Address config option.
    - Change "AllowUnverifiedNodes" to "AllowInvalidNodes", to
      reflect the updated flags in our v2 dir protocol.

  o Config option features:
    - Add a new config option FastFirstHopPK (on by default) so clients
      do a trivial crypto handshake for their first hop, since TLS has
      already taken care of confidentiality and authentication.
    - Let the user set ControlListenAddress in the torrc. This can be
      dangerous, but there are some cases (like a secured LAN) where it
      makes sense.
    - New config options to help controllers: FetchServerDescriptors
      and FetchHidServDescriptors for whether to fetch server
      info and hidserv info or let the controller do it, and
      PublishServerDescriptor and PublishHidServDescriptors.
    - Also let the controller set the __AllDirActionsPrivate config
      option if you want all directory fetches/publishes to happen via
      Tor (it assumes your controller bootstraps your circuits).
    - Add "HardwareAccel" config option: support for crypto hardware
      accelerators via OpenSSL. Off by default, until we find somebody
      smart who can test it for us. (It appears to produce seg faults
      in at least some cases.)
    - New config option "AuthDirRejectUnlisted" for directory authorities
      as a panic button: if we get flooded with unusable servers we can
      revert to only listing servers in the approved-routers file.
    - Directory authorities can now reject/invalidate by key and IP,
      with the config options "AuthDirInvalid" and "AuthDirReject", or
      by marking a fingerprint as "!reject" or "!invalid" (as its
      nickname) in the approved-routers file. This is useful since
      currently we automatically list servers as running and usable
      even if we know they're jerks.
    - Add a new config option TestSocks so people can see whether their
      applications are using socks4, socks4a, socks5-with-ip, or
      socks5-with-fqdn. This way they don't have to keep mucking
      with tcpdump and wondering if something got cached somewhere.
    - Add "private:*" as an alias in configuration for policies. Now
      you can simplify your exit policy rather than needing to list
      every single internal or nonroutable network space.
    - Accept "private:*" in routerdesc exit policies; not generated yet
      because older Tors do not understand it.
    - Add configuration option "V1AuthoritativeDirectory 1" which
      moria1, moria2, and tor26 have set.
    - Implement an option, VirtualAddrMask, to set which addresses
      get handed out in response to mapaddress requests. This works
      around a bug in tsocks where 127.0.0.0/8 is never socksified.
    - Add a new config option FetchUselessDescriptors, off by default,
      for when you plan to run "exitlist" on your client and you want
      to know about even the non-running descriptors.
    - SocksTimeout: How long do we let a socks connection wait
      unattached before we fail it?
    - CircuitBuildTimeout: Cull non-open circuits that were born
      at least this many seconds ago.
    - CircuitIdleTimeout: Cull open clean circuits that were born
      at least this many seconds ago.
    - New config option SafeSocks to reject all application connections
      using unsafe socks protocols. Defaults to off.

  o Improved and clearer log messages:
    - Reduce clutter in server logs. We're going to try to make
      them actually usable now. New config option ProtocolWarnings that
      lets you hear about how _other Tors_ are breaking the protocol. Off
      by default.
    - Divide log messages into logging domains. Once we put some sort
      of interface on this, it will let people looking at more verbose
      log levels specify the topics they want to hear more about.
    - Log server fingerprint on startup, so new server operators don't
      have to go hunting around their filesystem for it.
    - Provide dire warnings to any users who set DirServer manually;
      move it out of torrc.sample and into torrc.complete.
    - Make the log message less scary when all the dirservers are
      temporarily unreachable.
    - When tor_socketpair() fails in Windows, give a reasonable
      Windows-style errno back.
    - Improve tor_gettimeofday() granularity on windows.
    - We were printing the number of idle dns workers incorrectly when
      culling them.
    - Handle duplicate lines in approved-routers files without warning.
    - We were whining about using socks4 or socks5-with-local-lookup
      even when it's an IP address in the "virtual" range we designed
      exactly for this case.
    - Check for named servers when looking them up by nickname;
      warn when we're calling a non-named server by its nickname;
      don't warn twice about the same name.
    - Downgrade the dirserver log messages when whining about
      unreachability.
    - Correct "your server is reachable" log entries to indicate that
      it was self-testing that told us so.
    - If we're trying to be a Tor server and running Windows 95/98/ME
      as a server, explain that we'll likely crash.
    - Provide a more useful warn message when our onion queue gets full:
      the CPU is too slow or the exit policy is too liberal.
    - Don't warn when we receive a 503 from a dirserver/cache -- this
      will pave the way for them being able to refuse if they're busy.
    - When we fail to bind a listener, try to provide a more useful
      log message: e.g., "Is Tor already running?"
    - Only start testing reachability once we've established a
      circuit. This will make startup on dir authorities less noisy.
    - Don't try to upload hidden service descriptors until we have
      established a circuit.
    - Tor didn't warn when it failed to open a log file.
    - Warn when listening on a public address for socks. We suspect a
      lot of people are setting themselves up as open socks proxies,
      and they have no idea that jerks on the Internet are using them,
      since they simply proxy the traffic into the Tor network.
    - Give a useful message when people run Tor as the wrong user,
      rather than telling them to start chowning random directories.
    - Fix a harmless bug that was causing Tor servers to log
      "Got an end because of misc error, but we're not an AP. Closing."
    - Fix wrong log message when you add a "HiddenServiceNodes" config
      line without any HiddenServiceDir line (reported by Chris Thomas).
    - Directory authorities now stop whining so loudly about bad
      descriptors that they fetch from other dirservers. So when there's
      a log complaint, it's for sure from a freshly uploaded descriptor.
    - When logging via syslog, include the pid whenever we provide
      a log entry. Suggested by Todd Fries.
    - When we're shutting down and we do something like try to post a
      server descriptor or rendezvous descriptor, don't complain that
      we seem to be unreachable. Of course we are, we're shutting down.
    - Change log line for unreachability to explicitly suggest /etc/hosts
      as the culprit. Also make it clearer what IP address and ports we're
      testing for reachability.
    - Put quotes around user-supplied strings when logging so users are
      more likely to realize if they add bad characters (like quotes)
      to the torrc.
    - NT service patch from Matt Edman to improve error messages on Win32.


Changes in version 0.1.0.17 - 2006-02-17
  o Crash bugfixes on 0.1.0.x:
    - When servers with a non-zero DirPort came out of hibernation,
      sometimes they would trigger an assert.

  o Other important bugfixes:
    - On platforms that don't have getrlimit (like Windows), we were
      artificially constraining ourselves to a max of 1024
      connections. Now just assume that we can handle as many as 15000
      connections. Hopefully this won't cause other problems.

  o Backported features:
    - When we're a server, a client asks for an old-style directory,
      and our write bucket is empty, don't give it to him. This way
      small servers can continue to serve the directory *sometimes*,
      without getting overloaded.
    - Whenever you get a 503 in response to a directory fetch, try
      once more. This will become important once servers start sending
      503's whenever they feel busy.
    - Fetch a new directory every 120 minutes, not every 40 minutes.
      Now that we have hundreds of thousands of users running the old
      directory algorithm, it's starting to hurt a lot.
    - Bump up the period for forcing a hidden service descriptor upload
      from 20 minutes to 1 hour.


Changes in version 0.1.0.16 - 2006-01-02
  o Crash bugfixes on 0.1.0.x:
    - On Windows, build with a libevent patch from "I-M Weasel" to avoid
      corrupting the heap, losing FDs, or crashing when we need to resize
      the fd_sets. (This affects the Win32 binaries, not Tor's sources.)
    - It turns out sparc64 platforms crash on unaligned memory access
      too -- so detect and avoid this.
    - Handle truncated compressed data correctly (by detecting it and
      giving an error).
    - Fix possible-but-unlikely free(NULL) in control.c.
    - When we were closing connections, there was a rare case that
      stomped on memory, triggering seg faults and asserts.
    - Avoid potential infinite recursion when building a descriptor. (We
      don't know that it ever happened, but better to fix it anyway.)
    - We were neglecting to unlink marked circuits from soon-to-close OR
      connections, which caused some rare scribbling on freed memory.
    - Fix a memory stomping race bug when closing the joining point of two
      rendezvous circuits.
    - Fix an assert in time parsing found by Steven Murdoch.

  o Other bugfixes on 0.1.0.x:
    - When we're doing reachability testing, provide more useful log
      messages so the operator knows what to expect.
    - Do not check whether DirPort is reachable when we are suppressing
      advertising it because of hibernation.
    - When building with -static or on Solaris, we sometimes needed -ldl.
    - One of the dirservers (tor26) changed its IP address.
    - When we're deciding whether a stream has enough circuits around
      that can handle it, count the freshly dirty ones and not the ones
      that are so dirty they won't be able to handle it.
    - When we're expiring old circuits, we had a logic error that caused
      us to close new rendezvous circuits rather than old ones.
    - Give a more helpful log message when you try to change ORPort via
      the controller: you should upgrade Tor if you want that to work.
    - We were failing to parse Tor versions that start with "Tor ".
    - Tolerate faulty streams better: when a stream fails for reason
      exitpolicy, stop assuming that the router is lying about his exit
      policy. When a stream fails for reason misc, allow it to retry just
      as if it was resolvefailed. When a stream has failed three times,
      reset its failure count so we can try again and get all three tries.


Changes in version 0.1.0.15 - 2005-09-23
  o Bugfixes on 0.1.0.x:
    - Reject ports 465 and 587 (spam targets) in default exit policy.
    - Don't crash when we don't have any spare file descriptors and we
      try to spawn a dns or cpu worker.
    - Get rid of IgnoreVersion undocumented config option, and make us
      only warn, never exit, when we're running an obsolete version.
    - Don't try to print a null string when your server finds itself to
      be unreachable and the Address config option is empty.
    - Make the numbers in read-history and write-history into uint64s,
      so they don't overflow and publish negatives in the descriptor.
    - Fix a minor memory leak in smartlist_string_remove().
    - We were only allowing ourselves to upload a server descriptor at
      most every 20 minutes, even if it changed earlier than that.
    - Clean up log entries that pointed to old URLs.


Changes in version 0.1.0.14 - 2005-08-08
  o Bugfixes on 0.1.0.x:
      - Fix the other half of the bug with crypto handshakes
        (CVE-2005-2643).
      - Fix an assert trigger if you send a 'signal term' via the
        controller when it's listening for 'event info' messages.


Changes in version 0.1.0.13 - 2005-08-04
  o Bugfixes on 0.1.0.x:
    - Fix a critical bug in the security of our crypto handshakes.
    - Fix a size_t underflow in smartlist_join_strings2() that made
      it do bad things when you hand it an empty smartlist.
    - Fix Windows installer to ship Tor license (thanks to Aphex for
      pointing out this oversight) and put a link to the doc directory
      in the start menu.
    - Explicitly set no-unaligned-access for sparc: it turns out the
      new gcc's let you compile broken code, but that doesn't make it
      not-broken.


Changes in version 0.1.0.12 - 2005-07-18
  o New directory servers:
      - tor26 has changed IP address.

  o Bugfixes on 0.1.0.x:
    - Fix a possible double-free in tor_gzip_uncompress().
    - When --disable-threads is set, do not search for or link against
      pthreads libraries.
    - Don't trigger an assert if an authoritative directory server
      claims its dirport is 0.
    - Fix bug with removing Tor as an NT service: some people were
      getting "The service did not return an error." Thanks to Matt
      Edman for the fix.


Changes in version 0.1.0.11 - 2005-06-30
  o Bugfixes on 0.1.0.x:
    - Fix major security bug: servers were disregarding their
      exit policies if clients behaved unexpectedly.
    - Make OS X init script check for missing argument, so we don't
      confuse users who invoke it incorrectly.
    - Fix a seg fault in "tor --hash-password foo".
    - The MAPADDRESS control command was broken.


Changes in version 0.1.0.10 - 2005-06-14
  o Fixes on Win32:
    - Make NT services work and start on startup on Win32 (based on
      patch by Matt Edman). See the FAQ entry for details.
    - Make 'platform' string in descriptor more accurate for Win32
      servers, so it's not just "unknown platform".
    - REUSEADDR on normal platforms means you can rebind to the port
      right after somebody else has let it go. But REUSEADDR on Win32
      means you can bind to the port _even when somebody else already
      has it bound_! So, don't do that on Win32.
    - Clean up the log messages when starting on Win32 with no config
      file.
    - Allow seeding the RNG on Win32 even when you're not running as
      Administrator. If seeding the RNG on Win32 fails, quit.

  o Assert / crash bugs:
    - Refuse relay cells that claim to have a length larger than the
      maximum allowed. This prevents a potential attack that could read
      arbitrary memory (e.g. keys) from an exit server's process
      (CVE-2005-2050).
    - If unofficial Tor clients connect and send weird TLS certs, our
      Tor server triggers an assert. Stop asserting, and start handling
      TLS errors better in other situations too.
    - Fix a race condition that can trigger an assert when we have a
      pending create cell and an OR connection attempt fails.

  o Resource leaks:
    - Use pthreads for worker processes rather than forking. This was
      forced because when we forked, we ended up wasting a lot of
      duplicate ram over time.
      - Also switch to foo_r versions of some library calls to allow
        reentry and threadsafeness.
      - Implement --disable-threads configure option. Disable threads on
        netbsd and openbsd by default, because they have no reentrant
        resolver functions (!), and on solaris since it has other
        threading issues.
    - Fix possible bug on threading platforms (e.g. win32) which was
      leaking a file descriptor whenever a cpuworker or dnsworker died.
    - Fix a minor memory leak when somebody establishes an introduction
      point at your Tor server.
    - Fix possible memory leak in tor_lookup_hostname(). (Thanks to
      Adam Langley.)
    - Add ./configure --with-dmalloc option, to track memory leaks.
    - And try to free all memory on closing, so we can detect what
      we're leaking.

  o Protocol correctness:
    - When we've connected to an OR and handshaked but didn't like
      the result, we were closing the conn without sending destroy
      cells back for pending circuits. Now send those destroys.
    - Start sending 'truncated' cells back rather than destroy cells
      if the circuit closes in front of you. This means we won't have
      to abandon partially built circuits.
    - Handle changed router status correctly when dirserver reloads
      fingerprint file. We used to be dropping all unverified descriptors
      right then. The bug was hidden because we would immediately
      fetch a directory from another dirserver, which would include the
      descriptors we just dropped.
    - Revise tor-spec to add more/better stream end reasons.
    - Revise all calls to connection_edge_end to avoid sending 'misc',
      and to take errno into account where possible.
    - Client now retries when streams end early for 'hibernating' or
      'resource limit' reasons, rather than failing them.
    - Try to be more zealous about calling connection_edge_end when
      things go bad with edge conns in connection.c.

  o Robustness improvements:
    - Better handling for heterogeneous / unreliable nodes:
      - Annotate circuits with whether they aim to contain high uptime
        nodes and/or high capacity nodes. When building circuits, choose
        appropriate nodes.
      - This means that every single node in an intro rend circuit,
        not just the last one, will have a minimum uptime.
      - New config option LongLivedPorts to indicate application streams
        that will want high uptime circuits.
      - Servers reset uptime when a dir fetch entirely fails. This
        hopefully reflects stability of the server's network connectivity.
      - If somebody starts his tor server in Jan 2004 and then fixes his
        clock, don't make his published uptime be a year.
      - Reset published uptime when we wake up from hibernation.
    - Introduce a notion of 'internal' circs, which are chosen without
      regard to the exit policy of the last hop. Intro and rendezvous
      circs must be internal circs, to avoid leaking information. Resolve
      and connect streams can use internal circs if they want.
    - New circuit pooling algorithm: keep track of what destination ports
      we've used recently (start out assuming we'll want to use 80), and
      make sure to have enough circs around to satisfy these ports. Also
      make sure to have 2 internal circs around if we've required internal
      circs lately (and with high uptime if we've seen that lately too).
    - Turn addr_policy_compare from a tristate to a quadstate; this should
      help address our "Ah, you allow 1.2.3.4:80. You are a good choice
      for google.com" problem.
    - When a client asks us for a dir mirror and we don't have one,
      launch an attempt to get a fresh one.
    - First cut at support for "create-fast" cells. Clients can use
      these when extending to their first hop, since the TLS already
      provides forward secrecy and authentication. Not enabled on
      clients yet.

  o Reachability testing.
    - Your Tor server will automatically try to see if its ORPort and
      DirPort are reachable from the outside, and it won't upload its
      descriptor until it decides at least ORPort is reachable (when
      DirPort is not yet found reachable, publish it as zero).
    - When building testing circs for ORPort testing, use only
      high-bandwidth nodes, so fewer circuits fail.
    - Notice when our IP changes, and reset stats/uptime/reachability.
    - Authdirservers don't do ORPort reachability detection, since
      they're in clique mode, so it will be rare to find a server not
      already connected to them.
    - Authdirservers now automatically approve nodes running 0.1.0.2-rc
      or later.

  o Dirserver fixes:
    - Now we allow two unverified servers with the same nickname
      but different keys. But if a nickname is verified, only that
      nickname+key are allowed.
    - If you're an authdirserver connecting to an address:port,
      and it's not the OR you were expecting, forget about that
      descriptor. If he *was* the one you were expecting, then forget
      about all other descriptors for that address:port.
    - Allow servers to publish descriptors from 12 hours in the future.
      Corollary: only whine about clock skew from the dirserver if
      he's a trusted dirserver (since now even verified servers could
      have quite wrong clocks).
    - Require servers that use the default dirservers to have public IP
      addresses. We have too many servers that are configured with private
      IPs and their admins never notice the log entries complaining that
      their descriptors are being rejected.

  o Efficiency improvements:
    - Use libevent. Now we can use faster async cores (like epoll, kpoll,
      and /dev/poll), and hopefully work better on Windows too.
      - Apple's OS X 10.4.0 ships with a broken kqueue API, and using
        kqueue on 10.3.9 causes kernel panics. Don't use kqueue on OS X.
      - Find libevent even if it's hiding in /usr/local/ and your
        CFLAGS and LDFLAGS don't tell you to look there.
      - Be able to link with libevent as a shared library (the default
        after 1.0d), even if it's hiding in /usr/local/lib and even
        if you haven't added /usr/local/lib to your /etc/ld.so.conf,
        assuming you're running gcc. Otherwise fail and give a useful
        error message.
    - Switch to a new buffer management algorithm, which tries to avoid
      reallocing and copying quite as much. In first tests it looks like
      it uses *more* memory on average, but less cpu.
    - Switch our internal buffers implementation to use a ring buffer,
      to hopefully improve performance for fast servers a lot.
    - Reenable the part of the code that tries to flush as soon as an
      OR outbuf has a full TLS record available. Perhaps this will make
      OR outbufs not grow as huge except in rare cases, thus saving lots
      of CPU time plus memory.
    - Improve performance for dirservers: stop re-parsing the whole
      directory every time you regenerate it.
    - Keep a big splay tree of (circid,orconn)->circuit mappings to make
      it much faster to look up a circuit for each relay cell.
    - Remove most calls to assert_all_pending_dns_resolves_ok(),
      since they're eating our cpu on exit nodes.
    - Stop wasting time doing a case insensitive comparison for every
      dns name every time we do any lookup. Canonicalize the names to
      lowercase when you first see them.

  o Hidden services:
    - Handle unavailable hidden services better. Handle slow or busy
      hidden services better.
    - Cannibalize GENERAL circs to be C_REND, C_INTRO, S_INTRO, and S_REND
      circ as necessary, if there are any completed ones lying around
      when we try to launch one.
    - Make hidden services try to establish a rendezvous for 30 seconds
      after fetching the descriptor, rather than for n (where n=3)
      attempts to build a circuit.
    - Adjust maximum skew and age for rendezvous descriptors: let skew
      be 48 hours rather than 90 minutes.
    - Reject malformed .onion addresses rather then passing them on as
      normal web requests.

  o Controller:
    - More Tor controller support. See
      http://tor.eff.org/doc/control-spec.txt for all the new features,
      including signals to emulate unix signals from any platform;
      redirectstream; extendcircuit; mapaddress; getinfo; postdescriptor;
      closestream; closecircuit; etc.
    - Encode hashed controller passwords in hex instead of base64,
      to make it easier to write controllers.
    - Revise control spec and implementation to allow all log messages to
      be sent to controller with their severities intact (suggested by
      Matt Edman). Disable debug-level logs while delivering a debug-level
      log to the controller, to prevent loop. Update TorControl to handle
      new log event types.

  o New config options/defaults:
    - Begin scrubbing sensitive strings from logs by default. Turn off
      the config option SafeLogging if you need to do debugging.
    - New exit policy: accept most low-numbered ports, rather than
      rejecting most low-numbered ports.
    - Put a note in the torrc about abuse potential with the default
      exit policy.
    - Add support for CONNECTing through https proxies, with "HttpsProxy"
      config option.
    - Add HttpProxyAuthenticator and HttpsProxyAuthenticator support
      based on patch from Adam Langley (basic auth only).
    - Bump the default BandwidthRate from 1 MB to 2 MB, to accommodate
      the fast servers that have been joining lately. (Clients are now
      willing to load balance over up to 2 MB of advertised bandwidth
      capacity too.)
    - New config option MaxAdvertisedBandwidth which lets you advertise
      a low bandwidthrate (to not attract as many circuits) while still
      allowing a higher bandwidthrate in reality.
    - Require BandwidthRate to be at least 20kB/s for servers.
    - Add a NoPublish config option, so you can be a server (e.g. for
      testing running Tor servers in other Tor networks) without
      publishing your descriptor to the primary dirservers.
    - Add a new AddressMap config directive to rewrite incoming socks
      addresses. This lets you, for example, declare an implicit
      required exit node for certain sites.
    - Add a new TrackHostExits config directive to trigger addressmaps
      for certain incoming socks addresses -- for sites that break when
      your exit keeps changing (based on patch from Mike Perry).
    - Split NewCircuitPeriod option into NewCircuitPeriod (30 secs),
      which describes how often we retry making new circuits if current
      ones are dirty, and MaxCircuitDirtiness (10 mins), which describes
      how long we're willing to make use of an already-dirty circuit.
    - Change compiled-in SHUTDOWN_WAIT_LENGTH from a fixed 30 secs to
      a config option "ShutdownWaitLength" (when using kill -INT on
      servers).
    - Fix an edge case in parsing config options: if they say "--"
      on the commandline, it's not a config option (thanks weasel).
    - New config option DirAllowPrivateAddresses for authdirservers.
      Now by default they refuse router descriptors that have non-IP or
      private-IP addresses.
    - Change DirFetchPeriod/StatusFetchPeriod to have a special "Be
      smart" default value: low for servers and high for clients.
    - Some people were putting "Address  " in their torrc, and they had
      a buggy resolver that resolved " " to 0.0.0.0. Oops.
    - If DataDir is ~/.tor, and that expands to /.tor, then default to
      LOCALSTATEDIR/tor instead.
    - Implement --verify-config command-line option to check if your torrc
      is valid without actually launching Tor.

  o Logging improvements:
    - When dirservers refuse a server descriptor, we now log its
      contactinfo, platform, and the poster's IP address.
    - Only warn once per nickname from add_nickname_list_to_smartlist()
      per failure, so an entrynode or exitnode choice that's down won't
      yell so much.
    - When we're connecting to an OR and he's got a different nickname/key
      than we were expecting, only complain loudly if we're an OP or a
      dirserver. Complaining loudly to the OR admins just confuses them.
    - Whine at you if you're a server and you don't set your contactinfo.
    - Warn when exit policy implicitly allows local addresses.
    - Give a better warning when some other server advertises an
      ORPort that is actually an apache running ssl.
    - If we get an incredibly skewed timestamp from a dirserver mirror
      that isn't a verified OR, don't warn -- it's probably him that's
      wrong.
    - When a dirserver causes you to give a warn, mention which dirserver
      it was.
    - Initialize libevent later in the startup process, so the logs are
      already established by the time we start logging libevent warns.
    - Use correct errno on win32 if libevent fails.
    - Check and warn about known-bad/slow libevent versions.
    - Stop warning about sigpipes in the logs. We're going to
      pretend that getting these occassionally is normal and fine.

  o New contrib scripts:
    - New experimental script tor/contrib/exitlist: a simple python
      script to parse directories and find Tor nodes that exit to listed
      addresses/ports.
    - New experimental script tor/contrib/ExerciseServer.py (needs more
      work) that uses the controller interface to build circuits and
      fetch pages over them. This will help us bootstrap servers that
      have lots of capacity but haven't noticed it yet.
    - New experimental script tor/contrib/PathDemo.py (needs more work)
      that uses the controller interface to let you choose whole paths
      via addresses like
      "<hostname>.<path,separated by dots>.<length of path>.path"
    - New contributed script "privoxy-tor-toggle" to toggle whether
      Privoxy uses Tor. Seems to be configured for Debian by default.
    - Have torctl.in/tor.sh.in check for location of su binary (needed
      on FreeBSD)

  o Misc bugfixes:
    - chdir() to your datadirectory at the *end* of the daemonize process,
      not the beginning. This was a problem because the first time you
      run tor, if your datadir isn't there, and you have runasdaemon set
      to 1, it will try to chdir to it before it tries to create it. Oops.
    - Fix several double-mark-for-close bugs, e.g. where we were finding
      a conn for a cell even if that conn is already marked for close.
    - Stop most cases of hanging up on a socks connection without sending
      the socks reject.
    - Fix a bug in the RPM package: set home directory for _tor to
      something more reasonable when first installing.
    - Stop putting nodename in the Platform string in server descriptors.
      It doesn't actually help, and it is confusing/upsetting some people.
    - When using preferred entry or exit nodes, ignore whether the
      circuit wants uptime or capacity. They asked for the nodes, they
      get the nodes.
    - Tie MAX_DIR_SIZE to MAX_BUF_SIZE, so now directory sizes won't get
      artificially capped at 500kB.
    - Cache local dns resolves correctly even when they're .exit
      addresses.
    - If we're hibernating and we get a SIGINT, exit immediately.
    - tor-resolve requests were ignoring .exit if there was a working circuit
      they could use instead.
    - Pay more attention to the ClientOnly config option.
    - Resolve OS X installer bugs: stop claiming to be 0.0.9.2 in certain
      installer screens; and don't put stuff into StartupItems unless
      the user asks you to.

  o Misc features:
    - Rewrite address "serifos.exit" to "externalIP.serifos.exit"
      rather than just rejecting it.
    - If our clock jumps forward by 100 seconds or more, assume something
      has gone wrong with our network and abandon all not-yet-used circs.
    - When an application is using socks5, give him the whole variety of
      potential socks5 responses (connect refused, host unreachable, etc),
      rather than just "success" or "failure".
    - A more sane version numbering system. See
      http://tor.eff.org/cvs/tor/doc/version-spec.txt for details.
    - Change version parsing logic: a version is "obsolete" if it is not
      recommended and (1) there is a newer recommended version in the
      same series, or (2) there are no recommended versions in the same
      series, but there are some recommended versions in a newer series.
      A version is "new" if it is newer than any recommended version in
      the same series.
    - Report HTTP reasons to client when getting a response from directory
      servers -- so you can actually know what went wrong.
    - Reject odd-looking addresses at the client (e.g. addresses that
      contain a colon), rather than having the server drop them because
      they're malformed.
    - Stop publishing socksport in the directory, since it's not
      actually meant to be public. For compatibility, publish a 0 there
      for now.
    - Since we ship our own Privoxy on OS X, tweak it so it doesn't write
      cookies to disk and doesn't log each web request to disk. (Thanks
      to Brett Carrington for pointing this out.)
    - Add OSX uninstall instructions. An actual uninstall script will
      come later.
    - Add "opt hibernating 1" to server descriptor to make it clearer
      whether the server is hibernating.


Changes in version 0.0.9.10 - 2005-06-16
  o Bugfixes on 0.0.9.x (backported from 0.1.0.10):
    - Refuse relay cells that claim to have a length larger than the
      maximum allowed. This prevents a potential attack that could read
      arbitrary memory (e.g. keys) from an exit server's process
      (CVE-2005-2050).


Changes in version 0.0.9.9 - 2005-04-23
  o Bugfixes on 0.0.9.x:
    - If unofficial Tor clients connect and send weird TLS certs, our
      Tor server triggers an assert. This release contains a minimal
      backport from the broader fix that we put into 0.1.0.4-rc.


Changes in version 0.0.9.8 - 2005-04-07
  o Bugfixes on 0.0.9.x:
    - We have a bug that I haven't found yet. Sometimes, very rarely,
      cpuworkers get stuck in the 'busy' state, even though the cpuworker
      thinks of itself as idle. This meant that no new circuits ever got
      established. Here's a workaround to kill any cpuworker that's been
      busy for more than 100 seconds.


Changes in version 0.0.9.7 - 2005-04-01
  o Bugfixes on 0.0.9.x:
    - Fix another race crash bug (thanks to Glenn Fink for reporting).
    - Compare identity to identity, not to nickname, when extending to
      a router not already in the directory. This was preventing us from
      extending to unknown routers. Oops.
    - Make sure to create OS X Tor user in <500 range, so we aren't
      creating actual system users.
    - Note where connection-that-hasn't-sent-end was marked, and fix
      a few really loud instances of this harmless bug (it's fixed more
      in 0.1.0.x).


Changes in version 0.0.9.6 - 2005-03-24
  o Bugfixes on 0.0.9.x (crashes and asserts):
    - Add new end stream reasons to maintainance branch. Fix bug where
      reason (8) could trigger an assert.  Prevent bug from recurring.
    - Apparently win32 stat wants paths to not end with a slash.
    - Fix assert triggers in assert_cpath_layer_ok(), where we were
      blowing away the circuit that conn->cpath_layer points to, then
      checking to see if the circ is well-formed. Backport check to make
      sure we dont use the cpath on a closed connection.
    - Prevent circuit_resume_edge_reading_helper() from trying to package
      inbufs for marked-for-close streams.
    - Don't crash on hup if your options->address has become unresolvable.
    - Some systems (like OS X) sometimes accept() a connection and tell
      you the remote host is 0.0.0.0:0. If this happens, due to some
      other mis-features, we get confused; so refuse the conn for now.

  o Bugfixes on 0.0.9.x (other):
    - Fix harmless but scary "Unrecognized content encoding" warn message.
    - Add new stream error reason: TORPROTOCOL reason means "you are not
      speaking a version of Tor I understand; say bye-bye to your stream."
    - Be willing to cache directories from up to ROUTER_MAX_AGE seconds
      into the future, now that we are more tolerant of skew. This
      resolves a bug where a Tor server would refuse to cache a directory
      because all the directories it gets are too far in the future;
      yet the Tor server never logs any complaints about clock skew.
    - Mac packaging magic: make man pages useable, and do not overwrite
      existing torrc files.
    - Make OS X log happily to /var/log/tor/tor.log


Changes in version 0.0.9.5 - 2005-02-22
  o Bugfixes on 0.0.9.x:
    - Fix an assert race at exit nodes when resolve requests fail.
    - Stop picking unverified dir mirrors--it only leads to misery.
    - Patch from Matt Edman to make NT services work better. Service
      support is still not compiled into the executable by default.
    - Patch from Dmitri Bely so the Tor service runs better under
      the win32 SYSTEM account.
    - Make tor-resolve actually work (?) on Win32.
    - Fix a sign bug when getrlimit claims to have 4+ billion
      file descriptors available.
    - Stop refusing to start when bandwidthburst == bandwidthrate.
    - When create cells have been on the onion queue more than five
      seconds, just send back a destroy and take them off the list.


Changes in version 0.0.9.4 - 2005-02-03
  o Bugfixes on 0.0.9:
    - Fix an assert bug that took down most of our servers: when
      a server claims to have 1 GB of bandwidthburst, don't
      freak out.
    - Don't crash as badly if we have spawned the max allowed number
      of dnsworkers, or we're out of file descriptors.
    - Block more file-sharing ports in the default exit policy.
    - MaxConn is now automatically set to the hard limit of max
      file descriptors we're allowed (ulimit -n), minus a few for
      logs, etc.
    - Give a clearer message when servers need to raise their
      ulimit -n when they start running out of file descriptors.
    - SGI Compatibility patches from Jan Schaumann.
    - Tolerate a corrupt cached directory better.
    - When a dirserver hasn't approved your server, list which one.
    - Go into soft hibernation after 95% of the bandwidth is used,
      not 99%. This is especially important for daily hibernators who
      have a small accounting max. Hopefully it will result in fewer
      cut connections when the hard hibernation starts.
    - Load-balance better when using servers that claim more than
      800kB/s of capacity.
    - Make NT services work (experimental, only used if compiled in).


Changes in version 0.0.9.3 - 2005-01-21
  o Bugfixes on 0.0.9:
    - Backport the cpu use fixes from main branch, so busy servers won't
      need as much processor time.
    - Work better when we go offline and then come back, or when we
      run Tor at boot before the network is up. We do this by
      optimistically trying to fetch a new directory whenever an
      application request comes in and we think we're offline -- the
      human is hopefully a good measure of when the network is back.
    - Backport some minimal hidserv bugfixes: keep rend circuits open as
      long as you keep using them; actually publish hidserv descriptors
      shortly after they change, rather than waiting 20-40 minutes.
    - Enable Mac startup script by default.
    - Fix duplicate dns_cancel_pending_resolve reported by Giorgos Pallas.
    - When you update AllowUnverifiedNodes or FirewallPorts via the
      controller's setconf feature, we were always appending, never
      resetting.
    - When you update HiddenServiceDir via setconf, it was screwing up
      the order of reading the lines, making it fail.
    - Do not rewrite a cached directory back to the cache; otherwise we
      will think it is recent and not fetch a newer one on startup.
    - Workaround for webservers that lie about Content-Encoding: Tor
      now tries to autodetect compressed directories and compression
      itself. This lets us Proxypass dir fetches through apache.


Changes in version 0.0.9.2 - 2005-01-04
  o Bugfixes on 0.0.9 (crashes and asserts):
    - Fix an assert on startup when the disk is full and you're logging
      to a file.
    - If you do socks4 with an IP of 0.0.0.x but *don't* provide a socks4a
      style address, then we'd crash.
    - Fix an assert trigger when the running-routers string we get from
      a dirserver is broken.
    - Make worker threads start and run on win32. Now win32 servers
      may work better.
    - Bandaid (not actually fix, but now it doesn't crash) an assert
      where the dns worker dies mysteriously and the main Tor process
      doesn't remember anything about the address it was resolving.

  o Bugfixes on 0.0.9 (Win32):
    - Workaround for brain-damaged __FILE__ handling on MSVC: keep Nick's
      name out of the warning/assert messages.
    - Fix a superficial "unhandled error on read" bug on win32.
    - The win32 installer no longer requires a click-through for our
      license, since our Free Software license grants rights but does not
      take any away.
    - Win32: When connecting to a dirserver fails, try another one
      immediately. (This was already working for non-win32 Tors.)
    - Stop trying to parse $HOME on win32 when hunting for default
      DataDirectory.
    - Make tor-resolve.c work on win32 by calling network_init().

  o Bugfixes on 0.0.9 (other):
    - Make 0.0.9.x build on Solaris again.
    - Due to a fencepost error, we were blowing away the \n when reporting
      confvalue items in the controller. So asking for multiple config
      values at once couldn't work.
    - When listing circuits that are pending on an opening OR connection,
      if we're an OR we were listing circuits that *end* at us as
      being pending on every listener, dns/cpu worker, etc. Stop that.
    - Dirservers were failing to create 'running-routers' or 'directory'
      strings if we had more than some threshold of routers. Fix them so
      they can handle any number of routers.
    - Fix a superficial "Duplicate mark for close" bug.
    - Stop checking for clock skew for OR connections, even for servers.
    - Fix a fencepost error that was chopping off the last letter of any
      nickname that is the maximum allowed nickname length.
    - Update URLs in log messages so they point to the new website.
    - Fix a potential problem in mangling server private keys while
      writing to disk (not triggered yet, as far as we know).
    - Include the licenses for other free software we include in Tor,
      now that we're shipping binary distributions more regularly.


Changes in version 0.0.9.1 - 2004-12-15
  o Bugfixes on 0.0.9:
    - Make hibernation actually work.
    - Make HashedControlPassword config option work.
    - When we're reporting event circuit status to a controller,
      don't use the stream status code.


Changes in version 0.0.9 - 2004-12-12
  o Bugfixes on 0.0.8.1 (Crashes and asserts):
    - Catch and ignore SIGXFSZ signals when log files exceed 2GB; our
      write() call will fail and we handle it there.
    - When we run out of disk space, or other log writing error, don't
      crash. Just stop logging to that log and continue.
    - Fix isspace() and friends so they still make Solaris happy
      but also so they don't trigger asserts on win32.
    - Fix assert failure on malformed socks4a requests.
    - Fix an assert bug where a hidden service provider would fail if
      the first hop of his rendezvous circuit was down.
    - Better handling of size_t vs int, so we're more robust on 64
      bit platforms.

  o Bugfixes on 0.0.8.1 (Win32):
    - Make windows sockets actually non-blocking (oops), and handle
      win32 socket errors better.
    - Fix parse_iso_time on platforms without strptime (eg win32).
    - win32: when being multithreaded, leave parent fdarray open.
    - Better handling of winsock includes on non-MSV win32 compilers.
    - Change our file IO stuff (especially wrt OpenSSL) so win32 is
      happier.
    - Make unit tests work on win32.

  o Bugfixes on 0.0.8.1 (Path selection and streams):
    - Calculate timeout for waiting for a connected cell from the time
      we sent the begin cell, not from the time the stream started. If
      it took a long time to establish the circuit, we would time out
      right after sending the begin cell.
    - Fix router_compare_addr_to_addr_policy: it was not treating a port
      of * as always matching, so we were picking reject *:* nodes as
      exit nodes too. Oops.
    - When read() failed on a stream, we would close it without sending
      back an end. So 'connection refused' would simply be ignored and
      the user would get no response.
    - Stop a sigpipe: when an 'end' cell races with eof from the app,
      we shouldn't hold-open-until-flush if the eof arrived first.
    - Let resolve conns retry/expire also, rather than sticking around
      forever.
    - Fix more dns related bugs: send back resolve_failed and end cells
      more reliably when the resolve fails, rather than closing the
      circuit and then trying to send the cell. Also attach dummy resolve
      connections to a circuit *before* calling dns_resolve(), to fix
      a bug where cached answers would never be sent in RESOLVED cells.

  o Bugfixes on 0.0.8.1 (Circuits):
    - Finally fix a bug that's been plaguing us for a year:
      With high load, circuit package window was reaching 0. Whenever
      we got a circuit-level sendme, we were reading a lot on each
      socket, but only writing out a bit. So we would eventually reach
      eof. This would be noticed and acted on even when there were still
      bytes sitting in the inbuf.
    - Use identity comparison, not nickname comparison, to choose which
      half of circuit-ID-space each side gets to use. This is needed
      because sometimes we think of a router as a nickname, and sometimes
      as a hex ID, and we can't predict what the other side will do.

  o Bugfixes on 0.0.8.1 (Other):
    - Fix a whole slew of memory leaks.
    - Disallow NDEBUG. We don't ever want anybody to turn off debug.
    - If we are using select, make sure we stay within FD_SETSIZE.
    - When poll() is interrupted, we shouldn't believe the revents values.
    - Add a FAST_SMARTLIST define to optionally inline smartlist_get
      and smartlist_len, which are two major profiling offenders.
    - If do_hup fails, actually notice.
    - Flush the log file descriptor after we print "Tor opening log file",
      so we don't see those messages days later.
    - Hidden service operators now correctly handle version 1 style
      INTRODUCE1 cells (nobody generates them still, so not a critical
      bug).
    - Handle more errnos from accept() without closing the listener.
      Some OpenBSD machines were closing their listeners because
      they ran out of file descriptors.
    - Some people had wrapped their tor client/server in a script
      that would restart it whenever it died. This did not play well
      with our "shut down if your version is obsolete" code. Now people
      don't fetch a new directory if their local cached version is
      recent enough.
    - Make our autogen.sh work on ksh as well as bash.
    - Better torrc example lines for dirbindaddress and orbindaddress.
    - Improved bounds checking on parsed ints (e.g. config options and
      the ones we find in directories.)
    - Stop using separate defaults for no-config-file and
      empty-config-file. Now you have to explicitly turn off SocksPort,
      if you don't want it open.
    - We were starting to daemonize before we opened our logs, so if
      there were any problems opening logs, we would complain to stderr,
      which wouldn't work, and then mysteriously exit.
    - If a verified OR connects to us before he's uploaded his descriptor,
      or we verify him and hup but he still has the original TLS
      connection, then conn->nickname is still set like he's unverified.

  o Code security improvements, inspired by Ilja:
    - tor_snprintf wrapper over snprintf with consistent (though not C99)
      overflow behavior.
    - Replace sprintf with tor_snprintf. (I think they were all safe, but
      hey.)
    - Replace strcpy/strncpy with strlcpy in more places.
    - Avoid strcat; use tor_snprintf or strlcat instead.

  o Features (circuits and streams):
    - New circuit building strategy: keep a list of ports that we've
      used in the past 6 hours, and always try to have 2 circuits open
      or on the way that will handle each such port. Seed us with port
      80 so web users won't complain that Tor is "slow to start up".
    - Make kill -USR1 dump more useful stats about circuits.
    - When warning about retrying or giving up, print the address, so
      the user knows which one it's talking about.
    - If you haven't used a clean circuit in an hour, throw it away,
      just to be on the safe side. (This means after 6 hours a totally
      unused Tor client will have no circuits open.)
    - Support "foo.nickname.exit" addresses, to let Alice request the
      address "foo" as viewed by exit node "nickname". Based on a patch
      from Geoff Goodell.
    - If your requested entry or exit node has advertised bandwidth 0,
      pick it anyway.
    - Be more greedy about filling up relay cells -- we try reading again
      once we've processed the stuff we read, in case enough has arrived
      to fill the last cell completely.
    - Refuse application socks connections to port 0.
    - Use only 0.0.9pre1 and later servers for resolve cells.

  o Features (bandwidth):
    - Hibernation: New config option "AccountingMax" lets you
      set how many bytes per month (in each direction) you want to
      allow your server to consume. Rather than spreading those
      bytes out evenly over the month, we instead hibernate for some
      of the month and pop up at a deterministic time, work until
      the bytes are consumed, then hibernate again. Config option
      "MonthlyAccountingStart" lets you specify which day of the month
      your billing cycle starts on.
    - Implement weekly/monthly/daily accounting: now you specify your
      hibernation properties by
      AccountingMax N bytes|KB|MB|GB|TB
      AccountingStart day|week|month [day] HH:MM
        Defaults to "month 1 0:00".
    - Let bandwidth and interval config options be specified as 5 bytes,
      kb, kilobytes, etc; and as seconds, minutes, hours, days, weeks.

  o Features (directories):
    - New "router-status" line in directory, to better bind each verified
      nickname to its identity key.
    - Clients can ask dirservers for /dir.z to get a compressed version
      of the directory. Only works for servers running 0.0.9, of course.
    - Make clients cache directories and use them to seed their router
      lists at startup. This means clients have a datadir again.
    - Respond to content-encoding headers by trying to uncompress as
      appropriate.
    - Clients and servers now fetch running-routers; cache
      running-routers; compress running-routers; serve compressed
      running-routers.z
    - Make moria2 advertise a dirport of 80, so people behind firewalls
      will be able to get a directory.
    - Http proxy support
      - Dirservers translate requests for http://%s:%d/x to /x
      - You can specify "HttpProxy %s[:%d]" and all dir fetches will
        be routed through this host.
      - Clients ask for /tor/x rather than /x for new enough dirservers.
        This way we can one day coexist peacefully with apache.
      - Clients specify a "Host: %s%d" http header, to be compatible
        with more proxies, and so running squid on an exit node can work.
    - Protect dirservers from overzealous descriptor uploading -- wait
      10 seconds after directory gets dirty, before regenerating.

  o Features (packages and install):
    - Add NSI installer contributed by J Doe.
    - Apply NT service patch from Osamu Fujino. Still needs more work.
    - Commit VC6 and VC7 workspace/project files.
    - Commit a tor.spec for making RPM files, with help from jbash.
    - Add contrib/torctl.in contributed by Glenn Fink.
    - Make expand_filename handle ~ and ~username.
    - Use autoconf to enable largefile support where necessary. Use
      ftello where available, since ftell can fail at 2GB.
    - Ship src/win32/ in the tarball, so people can use it to build.
    - Make old win32 fall back to CWD if SHGetSpecialFolderLocation
      is broken.

  o Features (ui controller):
    - Control interface: a separate program can now talk to your
      client/server over a socket, and get/set config options, receive
      notifications of circuits and streams starting/finishing/dying,
      bandwidth used, etc. The next step is to get some GUIs working.
      Let us know if you want to help out. See doc/control-spec.txt .
    - Ship a contrib/tor-control.py as an example script to interact
      with the control port.
    - "tor --hash-password zzyxz" will output a salted password for
      use in authenticating to the control interface.
    - Implement the control-spec's SAVECONF command, to write your
      configuration to torrc.
    - Get cookie authentication for the controller closer to working.
    - When set_conf changes our server descriptor, upload a new copy.
      But don't upload it too often if there are frequent changes.

  o Features (config and command-line):
    - Deprecate unofficial config option abbreviations, and abbreviations
      not on the command line.
    - Configuration infrastructure support for warning on obsolete
      options.
    - Give a slightly more useful output for "tor -h".
    - Break DirFetchPostPeriod into:
      - DirFetchPeriod for fetching full directory,
      - StatusFetchPeriod for fetching running-routers,
      - DirPostPeriod for posting server descriptor,
      - RendPostPeriod for posting hidden service descriptors.
    - New log format in config:
      "Log minsev[-maxsev] stdout|stderr|syslog" or
      "Log minsev[-maxsev] file /var/foo"
    - DirPolicy config option, to let people reject incoming addresses
      from their dirserver.
    - "tor --list-fingerprint" will list your identity key fingerprint
      and then exit.
    - Make tor --version --version dump the cvs Id of every file.
    - New 'MyFamily nick1,...' config option for a server to
      specify other servers that shouldn't be used in the same circuit
      with it. Only believed if nick1 also specifies us.
    - New 'NodeFamily nick1,nick2,...' config option for a client to
      specify nodes that it doesn't want to use in the same circuit.
    - New 'Redirectexit pattern address:port' config option for a
      server to redirect exit connections, e.g. to a local squid.
    - Add "pass" target for RedirectExit, to make it easier to break
      out of a sequence of RedirectExit rules.
    - Make the dirservers file obsolete.
      - Include a dir-signing-key token in directories to tell the
        parsing entity which key is being used to sign.
      - Remove the built-in bulky default dirservers string.
      - New config option "Dirserver %s:%d [fingerprint]", which can be
        repeated as many times as needed. If no dirservers specified,
        default to moria1,moria2,tor26.
      - Make 'Routerfile' config option obsolete.
    - Discourage people from setting their dirfetchpostperiod more often
      than once per minute.

  o Features (other):
    - kill -USR2 now moves all logs to loglevel debug (kill -HUP to
      get back to normal.)
    - Accept *:706 (silc) in default exit policy.
    - Implement new versioning format for post 0.1.
    - Distinguish between TOR_TLS_CLOSE and TOR_TLS_ERROR, so we can
      log more informatively.
    - Check clock skew for verified servers, but allow unverified
      servers and clients to have any clock skew.
    - Make sure the hidden service descriptors are at a random offset
      from each other, to hinder linkability.
    - Clients now generate a TLS cert too, in preparation for having
      them act more like real nodes.
    - Add a pure-C tor-resolve implementation.
    - Use getrlimit and friends to ensure we can reach MaxConn (currently
      1024) file descriptors.
    - Raise the max dns workers from 50 to 100.


Changes in version 0.0.8.1 - 2004-10-13
  o Bugfixes:
    - Fix a seg fault that can be triggered remotely for Tor
      clients/servers with an open dirport.
    - Fix a rare assert trigger, where routerinfos for entries in
      our cpath would expire while we're building the path.
    - Fix a bug in OutboundBindAddress so it (hopefully) works.
    - Fix a rare seg fault for people running hidden services on
      intermittent connections.
    - Fix a bug in parsing opt keywords with objects.
    - Fix a stale pointer assert bug when a stream detaches and
      reattaches.
    - Fix a string format vulnerability (probably not exploitable)
      in reporting stats locally.
    - Fix an assert trigger: sometimes launching circuits can fail
      immediately, e.g. because too many circuits have failed recently.
    - Fix a compile warning on 64 bit platforms.


Changes in version 0.0.8 - 2004-08-25
  o Bugfixes:
    - Made our unit tests compile again on OpenBSD 3.5, and tor
      itself compile again on OpenBSD on a sparc64.
    - We were neglecting milliseconds when logging on win32, so
      everything appeared to happen at the beginning of each second.
    - Check directory signature _before_ you decide whether you're
      you're running an obsolete version and should exit.
    - Check directory signature _before_ you parse the running-routers
      list to decide who's running.
    - Check return value of fclose while writing to disk, so we don't
      end up with broken files when servers run out of disk space.
    - Port it to SunOS 5.9 / Athena
    - Fix two bugs in saving onion keys to disk when rotating, so
      hopefully we'll get fewer people using old onion keys.
    - Remove our mostly unused -- and broken -- hex_encode()
      function. Use base16_encode() instead. (Thanks to Timo Lindfors
      for pointing out this bug.)
    - Only pick and establish intro points after we've gotten a
      directory.
    - Fix assert triggers: if the other side returns an address 0.0.0.0,
      don't put it into the client dns cache.
    - If a begin failed due to exit policy, but we believe the IP
      address should have been allowed, switch that router to exitpolicy
      reject *:* until we get our next directory.

  o Protocol changes:
    - 'Extend' relay cell payloads now include the digest of the
      intended next hop's identity key. Now we can verify that we're
      extending to the right router, and also extend to routers we
      hadn't heard of before.

  o Features:
    - Tor nodes can now act as relays (with an advertised ORPort)
      without being manually verified by the dirserver operators.
      - Uploaded descriptors of unverified routers are now accepted
        by the dirservers, and included in the directory.
      - Verified routers are listed by nickname in the running-routers
        list; unverified routers are listed as "$<fingerprint>".
      - We now use hash-of-identity-key in most places rather than
        nickname or addr:port, for improved security/flexibility.
      - AllowUnverifiedNodes config option to let circuits choose no-name
        routers in entry,middle,exit,introduction,rendezvous positions.
        Allow middle and rendezvous positions by default.
      - When picking unverified routers, skip those with low uptime and/or
        low bandwidth, depending on what properties you care about.
      - ClientOnly option for nodes that never want to become servers.
    - Directory caching.
      - "AuthoritativeDir 1" option for the official dirservers.
      - Now other nodes (clients and servers) will cache the latest
        directory they've pulled down.
      - They can enable their DirPort to serve it to others.
      - Clients will pull down a directory from any node with an open
        DirPort, and check the signature/timestamp correctly.
      - Authoritative dirservers now fetch directories from other
        authdirservers, to stay better synced.
      - Running-routers list tells who's down also, along with noting
        if they're verified (listed by nickname) or unverified (listed
        by hash-of-key).
      - Allow dirservers to serve running-router list separately.
        This isn't used yet.
      - You can now fetch $DIRURL/running-routers to get just the
        running-routers line, not the whole descriptor list. (But
        clients don't use this yet.)
    - Clients choose nodes proportional to advertised bandwidth.
    - Clients avoid using nodes with low uptime as introduction points.
    - Handle servers with dynamic IP addresses: don't just replace
      options->Address with the resolved one at startup, and
      detect our address right before we make a routerinfo each time.
    - 'FascistFirewall' option to pick dirservers and ORs on specific
      ports; plus 'FirewallPorts' config option to tell FascistFirewall
      which ports are open. (Defaults to 80,443)
    - Try other dirservers immediately if the one you try is down. This
      should tolerate down dirservers better now.
    - ORs connect-on-demand to other ORs
      - If you get an extend cell to an OR you're not connected to,
        connect, handshake, and forward the create cell.
      - The authoritative dirservers stay connected to everybody,
        and everybody stays connected to 0.0.7 servers, but otherwise
        clients/servers expire unused connections after 5 minutes.
    - When servers get a sigint, they delay 30 seconds (refusing new
      connections) then exit. A second sigint causes immediate exit.
    - File and name management:
      - Look for .torrc if no CONFDIR "torrc" is found.
      - If no datadir is defined, then choose, make, and secure ~/.tor
        as datadir.
      - If torrc not found, exitpolicy reject *:*.
      - Expands ~/ in filenames to $HOME/ (but doesn't yet expand ~arma).
      - If no nickname is defined, derive default from hostname.
      - Rename secret key files, e.g. identity.key -> secret_id_key,
        to discourage people from mailing their identity key to tor-ops.
    - Refuse to build a circuit before the directory has arrived --
      it won't work anyway, since you won't know the right onion keys
      to use.
    - Parse tor version numbers so we can do an is-newer-than check
      rather than an is-in-the-list check.
    - New socks command 'resolve', to let us shim gethostbyname()
      locally.
      - A 'tor_resolve' script to access the socks resolve functionality.
      - A new socks-extensions.txt doc file to describe our
        interpretation and extensions to the socks protocols.
    - Add a ContactInfo option, which gets published in descriptor.
    - Write tor version at the top of each log file
    - New docs in the tarball:
      - tor-doc.html.
      - Document that you should proxy your SSL traffic too.
    - Log a warning if the user uses an unsafe socks variant, so people
      are more likely to learn about privoxy or socat.
    - Log a warning if you're running an unverified server, to let you
      know you might want to get it verified.
    - Change the default exit policy to reject the default edonkey,
      kazaa, gnutella ports.
    - Add replace_file() to util.[ch] to handle win32's rename().
    - Publish OR uptime in descriptor (and thus in directory) too.
    - Remember used bandwidth (both in and out), and publish 15-minute
      snapshots for the past day into our descriptor.
    - Be more aggressive about trying to make circuits when the network
      has changed (e.g. when you unsuspend your laptop).
    - Check for time skew on http headers; report date in response to
      "GET /".
    - If the entrynode config line has only one node, don't pick it as
      an exitnode.
    - Add strict{entry|exit}nodes config options. If set to 1, then
      we refuse to build circuits that don't include the specified entry
      or exit nodes.
    - OutboundBindAddress config option, to bind to a specific
      IP address for outgoing connect()s.
    - End truncated log entries (e.g. directories) with "[truncated]".


Changes in version 0.0.7.3 - 2004-08-12
  o Stop dnsworkers from triggering an assert failure when you
    ask them to resolve the host "".


Changes in version 0.0.7.2 - 2004-07-07
  o A better fix for the 0.0.0.0 problem, that will hopefully
    eliminate the remaining related assertion failures.


Changes in version 0.0.7.1 - 2004-07-04
  o When an address resolves to 0.0.0.0, treat it as a failed resolve,
    since internally we use 0.0.0.0 to signify "not yet resolved".


Changes in version 0.0.7 - 2004-06-07
  o Fixes for crashes and other obnoxious bugs:
    - Fix an epipe bug: sometimes when directory connections failed
      to connect, we would give them a chance to flush before closing
      them.
    - When we detached from a circuit because of resolvefailed, we
      would immediately try the same circuit twice more, and then
      give up on the resolve thinking we'd tried three different
      exit nodes.
    - Limit the number of intro circuits we'll attempt to build for a
      hidden service per 15-minute period.
    - Check recommended-software string *early*, before actually parsing
      the directory. Thus we can detect an obsolete version and exit,
      even if the new directory format doesn't parse.
  o Fixes for security bugs:
    - Remember which nodes are dirservers when you startup, and if a
      random OR enables his dirport, don't automatically assume he's
      a trusted dirserver.
  o Other bugfixes:
    - Directory connections were asking the wrong poll socket to
      start writing, and not asking themselves to start writing.
    - When we detached from a circuit because we sent a begin but
      didn't get a connected, we would use it again the first time;
      but after that we would correctly switch to a different one.
    - Stop warning when the first onion decrypt attempt fails; they
      will sometimes legitimately fail now that we rotate keys.
    - Override unaligned-access-ok check when $host_cpu is ia64 or
      arm. Apparently they allow it but the kernel whines.
    - Dirservers try to reconnect periodically too, in case connections
      have failed.
    - Fix some memory leaks in directory servers.
    - Allow backslash in Win32 filenames.
    - Made Tor build complain-free on FreeBSD, hopefully without
      breaking other BSD builds. We'll see.
    - Check directory signatures based on name of signer, not on whom
      we got the directory from. This will let us cache directories more
      easily.
    - Rotate dnsworkers and cpuworkers on SIGHUP, so they get new config
      settings too.
  o Features:
    - Doxygen markup on all functions and global variables.
    - Make directory functions update routerlist, not replace it. So
      now directory disagreements are not so critical a problem.
    - Remove the upper limit on number of descriptors in a dirserver's
      directory (not that we were anywhere close).
    - Allow multiple logfiles at different severity ranges.
    - Allow *BindAddress to specify ":port" rather than setting *Port
      separately. Allow multiple instances of each BindAddress config
      option, so you can bind to multiple interfaces if you want.
    - Allow multiple exit policy lines, which are processed in order.
      Now we don't need that huge line with all the commas in it.
    - Enable accept/reject policies on SOCKS connections, so you can bind
      to 0.0.0.0 but still control who can use your OP.
    - Updated the man page to reflect these features.


Changes in version 0.0.6.2 - 2004-05-16
  o Our integrity-checking digest was checking only the most recent cell,
    not the previous cells like we'd thought.
    Thanks to Stefan Mark for finding the flaw!


Changes in version 0.0.6.1 - 2004-05-06
  o Fix two bugs in our AES counter-mode implementation (this affected
    onion-level stream encryption, but not TLS-level). It turns
    out we were doing something much more akin to a 16-character
    polyalphabetic cipher. Oops.
    Thanks to Stefan Mark for finding the flaw!
  o Retire moria3 as a directory server, and add tor26 as a directory
    server.


Changes in version 0.0.6 - 2004-05-02
  o Features:
    - Hidden services and rendezvous points are implemented. Go to
      http://6sxoyfb3h2nvok2d.onion/ for an index of currently available
      hidden services. (This only works via a socks4a proxy such as
      Privoxy, and currently it's quite slow.)
    - We now rotate link (tls context) keys and onion keys.
    - CREATE cells now include oaep padding, so you can tell
      if you decrypted them correctly.
    - Retry stream correctly when we fail to connect because of
      exit-policy-reject (should try another) or can't-resolve-address.
    - When we hup a dirserver and we've *removed* a server from the
      approved-routers list, now we remove that server from the
      in-memory directories too.
    - Add bandwidthburst to server descriptor.
    - Directories now say which dirserver signed them.
    - Use a tor_assert macro that logs failed assertions too.
    - Since we don't support truncateds much, don't bother sending them;
      just close the circ.
    - Fetch randomness from /dev/urandom better (not via fopen/fread)
    - Better debugging for tls errors
    - Set Content-Type on the directory and hidserv descriptor.
    - Remove IVs from cipher code, since AES-ctr has none.
  o Bugfixes:
    - Fix an assert trigger for exit nodes that's been plaguing us since
      the days of 0.0.2prexx (thanks weasel!)
    - Fix a bug where we were closing tls connections intermittently.
      It turns out openssl keeps its errors around -- so if an error
      happens, and you don't ask about it, and then another openssl
      operation happens and succeeds, and you ask if there was an error,
      it tells you about the first error.
    - Fix a bug that's been lurking since 27 may 03 (!)
      When passing back a destroy cell, we would use the wrong circ id.
    - Don't crash if a conn that sent a begin has suddenly lost its circuit.
    - Some versions of openssl have an SSL_pending function that erroneously
      returns bytes when there is a non-application record pending.
    - Win32 fixes. Tor now compiles on win32 with no warnings/errors.
      o We were using an array of length zero in a few places.
      o Win32's gethostbyname can't resolve an IP to an IP.
      o Win32's close can't close a socket.
      o Handle windows socket errors correctly.
  o Portability:
    - check for <sys/limits.h> so we build on FreeBSD again, and
      <machine/limits.h> for NetBSD.


Changes in version 0.0.5 - 2004-03-30
  o Install torrc as torrc.sample -- we no longer clobber your
    torrc. (Woo!)
  o Fix mangled-state bug in directory fetching (was causing sigpipes).
  o Only build circuits after we've fetched the directory: clients were
    using only the directory servers before they'd fetched a directory.
    This also means longer startup time; so it goes.
  o Fix an assert trigger where an OP would fail to handshake, and we'd
    expect it to have a nickname.
  o Work around a tsocks bug: do a socks reject when AP connection dies
    early, else tsocks goes into an infinite loop.
  o Hold socks connection open until reply is flushed (if possible)
  o Make exit nodes resolve IPs to IPs immediately, rather than asking
    the dns farm to do it.
  o Fix c99 aliasing warnings in rephist.c
  o Don't include server descriptors that are older than 24 hours in the
    directory.
  o Give socks 'reject' replies their whole 15s to attempt to flush,
    rather than seeing the 60s timeout and assuming the flush had failed.
  o Clean automake droppings from the cvs repository
  o Add in a 'notice' log level for things the operator should hear
    but that aren't warnings


Changes in version 0.0.4 - 2004-03-26
  o When connecting to a dirserver or OR and the network is down,
    we would crash.


Changes in version 0.0.3 - 2004-03-26
  o Warn and fail if server chose a nickname with illegal characters
  o Port to Solaris and Sparc:
    - include missing header fcntl.h
    - have autoconf find -lsocket -lnsl automatically
    - deal with hardware word alignment
    - make uname() work (solaris has a different return convention)
    - switch from using signal() to sigaction()
  o Preliminary work on reputation system:
    - Keep statistics on success/fail of connect attempts; they're published
      by kill -USR1 currently.
    - Add a RunTesting option to try to learn link state by creating test
      circuits, even when SocksPort is off.
    - Remove unused open circuits when there are too many.


Changes in version 0.0.2 - 2004-03-19
    - Include strlcpy and strlcat for safer string ops
    - define INADDR_NONE so we compile (but still not run) on solaris


Changes in version 0.0.2pre27 - 2004-03-14
  o Bugfixes:
    - Allow internal tor networks (we were rejecting internal IPs,
      now we allow them if they're set explicitly).
    - And fix a few endian issues.


Changes in version 0.0.2pre26 - 2004-03-14
  o New features:
    - If a stream times out after 15s without a connected cell, don't
      try that circuit again: try a new one.
    - Retry streams at most 4 times. Then give up.
    - When a dirserver gets a descriptor from an unknown router, it
      logs its fingerprint (so the dirserver operator can choose to
      accept it even without mail from the server operator).
    - Inform unapproved servers when we reject their descriptors.
    - Make tor build on Windows again. It works as a client, who knows
      about as a server.
    - Clearer instructions in the torrc for how to set up a server.
    - Be more efficient about reading fd's when our global token bucket
      (used for rate limiting) becomes empty.
  o Bugfixes:
    - Stop asserting that computers always go forward in time. It's
      simply not true.
    - When we sent a cell (e.g. destroy) and then marked an OR connection
      expired, we might close it before finishing a flush if the other
      side isn't reading right then.
    - Don't allow dirservers to start if they haven't defined
      RecommendedVersions
    - We were caching transient dns failures. Oops.
    - Prevent servers from publishing an internal IP as their address.
    - Address a strcat vulnerability in circuit.c


Changes in version 0.0.2pre25 - 2004-03-04
  o New features:
    - Put the OR's IP in its router descriptor, not its fqdn. That way
      we'll stop being stalled by gethostbyname for nodes with flaky dns,
      e.g. poblano.
  o Bugfixes:
    - If the user typed in an address that didn't resolve, the server
      crashed.


Changes in version 0.0.2pre24 - 2004-03-03
  o Bugfixes:
    - Fix an assertion failure in dns.c, where we were trying to dequeue
      a pending dns resolve even if it wasn't pending
    - Fix a spurious socks5 warning about still trying to write after the
      connection is finished.
    - Hold certain marked_for_close connections open until they're finished
      flushing, rather than losing bytes by closing them too early.
    - Correctly report the reason for ending a stream
    - Remove some duplicate calls to connection_mark_for_close
    - Put switch_id and start_daemon earlier in the boot sequence, so it
      will actually try to chdir() to options.DataDirectory
    - Make 'make test' exit(1) if a test fails; fix some unit tests
    - Make tor fail when you use a config option it doesn't know about,
      rather than warn and continue.
    - Make --version work
    - Bugfixes on the rpm spec file and tor.sh, so it's more up to date


Changes in version 0.0.2pre23 - 2004-02-29
  o New features:
    - Print a statement when the first circ is finished, so the user
      knows it's working.
    - If a relay cell is unrecognized at the end of the circuit,
      send back a destroy. (So attacks to mutate cells are more
      clearly thwarted.)
    - New config option 'excludenodes' to avoid certain nodes for circuits.
    - When it daemonizes, it chdir's to the DataDirectory rather than "/",
      so you can collect coredumps there.
 o Bugfixes:
    - Fix a bug in tls flushing where sometimes data got wedged and
      didn't flush until more data got sent. Hopefully this bug was
      a big factor in the random delays we were seeing.
    - Make 'connected' cells include the resolved IP, so the client
      dns cache actually gets populated.
    - Disallow changing from ORPort=0 to ORPort>0 on hup.
    - When we time-out on a stream and detach from the circuit, send an
      end cell down it first.
    - Only warn about an unknown router (in exitnodes, entrynodes,
      excludenodes) after we've fetched a directory.


Changes in version 0.0.2pre22 - 2004-02-26
  o New features:
    - Servers publish less revealing uname information in descriptors.
    - More memory tracking and assertions, to crash more usefully when
      errors happen.
    - If the default torrc isn't there, just use some default defaults.
      Plus provide an internal dirservers file if they don't have one.
    - When the user tries to use Tor as an http proxy, give them an http
      501 failure explaining that we're a socks proxy.
    - Dump a new router.desc on hup, to help confused people who change
      their exit policies and then wonder why router.desc doesn't reflect
      it.
    - Clean up the generic tor.sh init script that we ship with.
  o Bugfixes:
    - If the exit stream is pending on the resolve, and a destroy arrives,
      then the stream wasn't getting removed from the pending list. I
      think this was the one causing recent server crashes.
    - Use a more robust poll on OSX 10.3, since their poll is flaky.
    - When it couldn't resolve any dirservers, it was useless from then on.
      Now it reloads the RouterFile (or default dirservers) if it has no
      dirservers.
    - Move the 'tor' binary back to /usr/local/bin/ -- it turns out
      many users don't even *have* a /usr/local/sbin/.


Changes in version 0.0.2pre21 - 2004-02-18
  o New features:
    - There's a ChangeLog file that actually reflects the changelog.
    - There's a 'torify' wrapper script, with an accompanying
      tor-tsocks.conf, that simplifies the process of using tsocks for
      tor. It even has a man page.
    - The tor binary gets installed to sbin rather than bin now.
    - Retry streams where the connected cell hasn't arrived in 15 seconds
    - Clean up exit policy handling -- get the default out of the torrc,
      so we can update it without forcing each server operator to fix
      his/her torrc.
    - Allow imaps and pop3s in default exit policy
  o Bugfixes:
    - Prevent picking middleman nodes as the last node in the circuit


Changes in version 0.0.2pre20 - 2004-01-30
  o New features:
    - We now have a deb package, and it's in debian unstable. Go to
      it, apt-getters. :)
    - I've split the TotalBandwidth option into BandwidthRate (how many
      bytes per second you want to allow, long-term) and
      BandwidthBurst (how many bytes you will allow at once before the cap
      kicks in).  This better token bucket approach lets you, say, set
      BandwidthRate to 10KB/s and BandwidthBurst to 10MB, allowing good
      performance while not exceeding your monthly bandwidth quota.
    - Push out a tls record's worth of data once you've got it, rather
      than waiting until you've read everything waiting to be read. This
      may improve performance by pipelining better. We'll see.
    - Add an AP_CONN_STATE_CONNECTING state, to allow streams to detach
      from failed circuits (if they haven't been connected yet) and attach
      to new ones.
    - Expire old streams that haven't managed to connect. Some day we'll
      have them reattach to new circuits instead.

  o Bugfixes:
    - Fix several memory leaks that were causing servers to become bloated
      after a while.
    - Fix a few very rare assert triggers. A few more remain.
    - Setuid to User _before_ complaining about running as root.


Changes in version 0.0.2pre19 - 2004-01-07
  o Bugfixes:
    - Fix deadlock condition in dns farm. We were telling a child to die by
      closing the parent's file descriptor to him. But newer children were
      inheriting the open file descriptor from the parent, and since they
      weren't closing it, the socket never closed, so the child never read
      eof, so he never knew to exit. Similarly, dns workers were holding
      open other sockets, leading to all sorts of chaos.
    - New cleaner daemon() code for forking and backgrounding.
    - If you log to a file, it now prints an entry at the top of the
      logfile so you know it's working.
    - The onionskin challenge length was 30 bytes longer than necessary.
    - Started to patch up the spec so it's not quite so out of date.


Changes in version 0.0.2pre18 - 2004-01-02
  o Bugfixes:
    - Fix endian issues with the 'integrity' field in the relay header.
    - Fix a potential bug where connections in state
      AP_CONN_STATE_CIRCUIT_WAIT might unexpectedly ask to write.


Changes in version 0.0.2pre17 - 2003-12-30
  o Bugfixes:
    - Made --debuglogfile (or any second log file, actually) work.
    - Resolved an edge case in get_unique_circ_id_by_conn where a smart
      adversary could force us into an infinite loop.

  o Features:
    - Each onionskin handshake now includes a hash of the computed key,
      to prove the server's identity and help perfect forward secrecy.
    - Changed cell size from 256 to 512 bytes (working toward compatibility
      with MorphMix).
    - Changed cell length to 2 bytes, and moved it to the relay header.
    - Implemented end-to-end integrity checking for the payloads of
      relay cells.
    - Separated streamid from 'recognized' (otherwise circuits will get
      messed up when we try to have streams exit from the middle). We
      use the integrity-checking to confirm that a cell is addressed to
      this hop.
    - Randomize the initial circid and streamid values, so an adversary who
      breaks into a node can't learn how many circuits or streams have
      been made so far.


Changes in version 0.0.2pre16 - 2003-12-14
  o Bugfixes:
    - Fixed a bug that made HUP trigger an assert
    - Fixed a bug where a circuit that immediately failed wasn't being
      counted as a failed circuit in counting retries.

  o Features:
    - Now we close the circuit when we get a truncated cell: otherwise we're
      open to an anonymity attack where a bad node in the path truncates
      the circuit and then we open streams at him.
    - Add port ranges to exit policies
    - Add a conservative default exit policy
    - Warn if you're running tor as root
    - on HUP, retry OR connections and close/rebind listeners
    - options.EntryNodes: try these nodes first when picking the first node
    - options.ExitNodes: if your best choices happen to include any of
      your preferred exit nodes, you choose among just those preferred
      exit nodes.
    - options.ExcludedNodes: nodes that are never picked in path building


Changes in version 0.0.2pre15 - 2003-12-03
  o Robustness and bugfixes:
    - Sometimes clients would cache incorrect DNS resolves, which would
      really screw things up.
    - An OP that goes offline would slowly leak all its sockets and stop
      working.
    - A wide variety of bugfixes in exit node selection, exit policy
      handling, and processing pending streams when a new circuit is
      established.
    - Pick nodes for a path only from those the directory says are up
    - Choose randomly from all running dirservers, not always the first one
    - Increase allowed http header size for directory fetch.
    - Stop writing to stderr (if we're daemonized it will be closed).
    - Enable -g always, so cores will be more useful to me.
    - Switch "-lcrypto -lssl" to "-lssl -lcrypto" for broken distributions.

  o Documentation:
    - Wrote a man page. It lists commonly used options.

  o Configuration:
    - Change default loglevel to warn.
    - Make PidFile default to null rather than littering in your CWD.
    - OnionRouter config option is now obsolete. Instead it just checks
      ORPort>0.
    - Moved to a single unified torrc file for both clients and servers.


Changes in version 0.0.2pre14 - 2003-11-29
  o Robustness and bugfixes:
    - Force the admin to make the DataDirectory himself
      - to get ownership/permissions right
      - so clients no longer make a DataDirectory and then never use it
    - fix bug where a client who was offline for 45 minutes would never
      pull down a directory again
    - fix (or at least hide really well) the dns assert bug that was
      causing server crashes
    - warnings and improved robustness wrt clockskew for certs
    - use the native daemon(3) to daemonize, when available
    - exit if bind() fails
    - exit if neither socksport nor orport is defined
    - include our own tor_timegm (Win32 doesn't have its own)
    - bugfix for win32 with lots of connections
    - fix minor bias in PRNG
    - make dirserver more robust to corrupt cached directory

  o Documentation:
    - Wrote the design document (woo)

  o Circuit building and exit policies:
    - Circuits no longer try to use nodes that the directory has told them
      are down.
    - Exit policies now support bitmasks (18.0.0.0/255.0.0.0) and
      bitcounts (18.0.0.0/8).
    - Make AP connections standby for a circuit if no suitable circuit
      exists, rather than failing
    - Circuits choose exit node based on addr/port, exit policies, and
      which AP connections are standing by
    - Bump min pathlen from 2 to 3
    - Relay end cells have a payload to describe why the stream ended.
    - If the stream failed because of exit policy, try again with a new
      circuit.
    - Clients have a dns cache to remember resolved addresses.
    - Notice more quickly when we have no working circuits

  o Configuration:
    - APPort is now called SocksPort
    - SocksBindAddress, ORBindAddress, DirBindAddress let you configure
      where to bind
    - RecommendedVersions is now a config variable rather than
      hardcoded (for dirservers)
    - Reloads config on HUP
    - Usage info on -h or --help
    - If you set User and Group config vars, it'll setu/gid to them.

Changes in version 0.0.2pre13 - 2003-10-19
  o General stability:
    - SSL_write no longer fails when it returns WANTWRITE and the number
      of bytes in the buf has changed by the next SSL_write call.
    - Fix segfault fetching directory when network is down
    - Fix a variety of minor memory leaks
    - Dirservers reload the fingerprints file on HUP, so I don't have
      to take down the network when I approve a new router
    - Default server config file has explicit Address line to specify fqdn

  o Buffers:
    - Buffers grow and shrink as needed (Cut process size from 20M to 2M)
    - Make listener connections not ever alloc bufs

  o Autoconf improvements:
    - don't clobber an external CFLAGS in ./configure
    - Make install now works
    - create var/lib/tor on make install
    - autocreate a tor.sh initscript to help distribs
    - autocreate the torrc and sample-server-torrc with correct paths

  o Log files and Daemonizing now work:
    - If --DebugLogFile is specified, log to it at -l debug
    - If --LogFile is specified, use it instead of commandline
    - If --RunAsDaemon is set, tor forks and backgrounds on startup

