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Changes in version 0.4.3.2-alpha - 2020-02-10
  This is the second stable alpha release in the Tor 0.4.3.x series. It
  fixes several bugs present in the previous alpha release. Anybody
  running the previous alpha should upgrade, and look for bugs in this
  one instead.

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  o Major bugfixes (onion service client, authorization):
    - On a NEWNYM signal, purge entries from the ephemeral client
      authorization cache. The permanent ones are kept. Fixes bug 33139;
      bugfix on 0.4.3.1-alpha.
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  o Minor features (best practices tracker):
    - Practracker now supports a --regen-overbroad option to regenerate
      the exceptions file, but only to revise exceptions to be _less_
      tolerant of best-practices violations. Closes ticket 32372.

  o Minor features (continuous integration):
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    - Run Doxygen Makefile target on Travis, so we can learn about
      regressions in our internal documentation. Closes ticket 32455.
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    - Stop allowing failures on the Travis CI stem tests job. It looks
      like all the stem hangs we were seeing before are now fixed.
      Closes ticket 33075.

  o Minor bugfixes (build system):
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    - Revise configure options that were either missing or incorrect in
      the configure summary. Fixes bug 32230; bugfix on 0.4.3.1-alpha.
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  o Minor bugfixes (controller protocol):
    - Fix a memory leak introduced by refactoring of control reply
      formatting code. Fixes bug 33039; bugfix on 0.4.3.1-alpha.
    - Fix a memory leak in GETINFO responses. Fixes bug 33103; bugfix
      on 0.4.3.1-alpha.
    - When receiving "ACTIVE" or "DORMANT" signals on the control port,
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      report them as SIGNAL events. Previously we would log a bug
      warning. Fixes bug 33104; bugfix on 0.4.0.1-alpha.
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  o Minor bugfixes (logging):
    - If we encounter a bug when flushing a buffer to a TLS connection,
      only log the bug once per invocation of the Tor process.
      Previously we would log with every occurrence, which could cause
      us to run out of disk space. Fixes bug 33093; bugfix
      on 0.3.2.2-alpha.
    - When logging a bug, do not say "Future instances of this warning
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      will be silenced" unless we are actually going to silence them.
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      Previously we would say this whenever a BUG() check failed in the
      code. Fixes bug 33095; bugfix on 0.4.1.1-alpha.

  o Minor bugfixes (onion service v2):
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    - Move a series of v2 onion service warnings to protocol-warning
      level because they can all be triggered remotely by a malformed
      request. Fixes bug 32706; bugfix on 0.1.1.14-alpha.
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  o Minor bugfixes (onion service v3, client authorization):
    - When removing client authorization credentials using the control
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      port, also remove the associated descriptor, so the onion service
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      can no longer be contacted. Fixes bug 33148; bugfix
      on 0.4.3.1-alpha.
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  o Minor bugfixes (pluggable transports):
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    - When receiving a message on standard error from a pluggable
      transport, log it at info level, rather than as a warning. Fixes
      bug 33005; bugfix on 0.4.0.1-alpha.
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  o Minor bugfixes (rust, build):
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    - Fix a syntax warning given by newer versions of Rust that was
      creating problems for our continuous integration. Fixes bug 33212;
      bugfix on 0.3.5.1-alpha.
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  o Minor bugfixes (TLS bug handling):
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    - When encountering a bug in buf_read_from_tls(), return a "MISC"
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      error code rather than "WANTWRITE". This change might help avoid
      some CPU-wasting loops if the bug is ever triggered. Bug reported
      by opara. Fixes bug 32673; bugfix on 0.3.0.4-alpha.

  o Code simplification and refactoring (mainloop):
    - Simplify the ip_address_changed() function by removing redundant
      checks. Closes ticket 33091.

  o Documentation (manpage):
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    - Split "Circuit Timeout" options and "Node Selection" options into
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      their own sections of the tor manpage. Closes tickets 32928 and
      32929. Work by Swati Thacker as part of Google Season of Docs.


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Changes in version 0.4.2.6 - 2020-01-30
  This is the second stable release in the 0.4.2.x series. It backports
  several bugfixes from 0.4.3.1-alpha, including some that had affected
  the Linux seccomp2 sandbox or Windows services. If you're running with
  one of those configurations, you'll probably want to upgrade;
  otherwise, you should be fine with 0.4.2.5.

  o Major bugfixes (linux seccomp sandbox, backport from 0.4.3.1-alpha):
    - Correct how we use libseccomp. Particularly, stop assuming that
      rules are applied in a particular order or that more rules are
      processed after the first match. Neither is the case! In
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      libseccomp <2.4.0 this led to some rules having no effect.
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      libseccomp 2.4.0 changed how rules are generated, leading to a
      different ordering, which in turn led to a fatal crash during
      startup. Fixes bug 29819; bugfix on 0.2.5.1-alpha. Patch by
      Peter Gerber.
    - Fix crash when reloading logging configuration while the
      experimental sandbox is enabled. Fixes bug 32841; bugfix on
      0.4.1.7. Patch by Peter Gerber.

  o Minor bugfixes (correctness checks, backport from 0.4.3.1-alpha):
    - Use GCC/Clang's printf-checking feature to make sure that
      tor_assertf() arguments are correctly typed. Fixes bug 32765;
      bugfix on 0.4.1.1-alpha.

  o Minor bugfixes (logging, crash, backport from 0.4.3.1-alpha):
    - Avoid a possible crash when trying to log a (fatal) assertion
      failure about mismatched magic numbers in configuration objects.
      Fixes bug 32771; bugfix on 0.4.2.1-alpha.

  o Minor bugfixes (testing, backport from 0.4.3.1-alpha):
    - When TOR_DISABLE_PRACTRACKER is set, do not apply it to the
      test_practracker.sh script. Doing so caused a test failure. Fixes
      bug 32705; bugfix on 0.4.2.1-alpha.
    - When TOR_DISABLE_PRACTRACKER is set, log a notice to stderr when
      skipping practracker checks. Fixes bug 32705; bugfix
      on 0.4.2.1-alpha.

  o Minor bugfixes (windows service, backport from 0.4.3.1-alpha):
    - Initialize the publish/subscribe system when running as a windows
      service. Fixes bug 32778; bugfix on 0.4.1.1-alpha.

  o Testing (backport from 0.4.3.1-alpha):
    - Turn off Tor's Sandbox in Chutney jobs, and run those jobs on
      Ubuntu Bionic. Turning off the Sandbox is a work-around, until we
      fix the sandbox errors in 32722. Closes ticket 32240.
    - Re-enable the Travis CI macOS Chutney build, but don't let it
      prevent the Travis job from finishing. (The Travis macOS jobs are
      slow, so we don't want to have it delay the whole CI process.)
      Closes ticket 32629.

  o Testing (continuous integration, backport from 0.4.3.1-alpha):
    - Use zstd in our Travis Linux builds. Closes ticket 32242.


Changes in version 0.4.1.8 - 2020-01-30
  This release backports several bugfixes from later release series,
  including some that had affected the Linux seccomp2 sandbox or Windows
  services. If you're running with one of those configurations, you'll
  probably want to upgrade; otherwise, you should be fine with your
  current version of 0.4.1.x.

  o Major bugfixes (linux seccomp sandbox, backport from 0.4.3.1-alpha):
    - Correct how we use libseccomp. Particularly, stop assuming that
      rules are applied in a particular order or that more rules are
      processed after the first match. Neither is the case! In
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      libseccomp <2.4.0 this led to some rules having no effect.
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      libseccomp 2.4.0 changed how rules are generated, leading to a
      different ordering, which in turn led to a fatal crash during
      startup. Fixes bug 29819; bugfix on 0.2.5.1-alpha. Patch by
      Peter Gerber.
    - Fix crash when reloading logging configuration while the
      experimental sandbox is enabled. Fixes bug 32841; bugfix on
      0.4.1.7. Patch by Peter Gerber.

  o Minor bugfixes (crash, backport form 0.4.2.4-rc):
    - When running Tor with an option like --verify-config or
      --dump-config that does not start the event loop, avoid crashing
      if we try to exit early because of an error. Fixes bug 32407;
      bugfix on 0.3.3.1-alpha.

  o Minor bugfixes (windows service, backport from 0.4.3.1-alpha):
    - Initialize the publish/subscribe system when running as a windows
      service. Fixes bug 32778; bugfix on 0.4.1.1-alpha.

  o Testing (backport from 0.4.3.1-alpha):
    - Turn off Tor's Sandbox in Chutney jobs, and run those jobs on
      Ubuntu Bionic. Turning off the Sandbox is a work-around, until we
      fix the sandbox errors in 32722. Closes ticket 32240.
    - Re-enable the Travis CI macOS Chutney build, but don't let it
      prevent the Travis job from finishing. (The Travis macOS jobs are
      slow, so we don't want to have it delay the whole CI process.)
      Closes ticket 32629.

  o Testing (continuous integration, backport from 0.4.3.1-alpha):
    - Use zstd in our Travis Linux builds. Closes ticket 32242.


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Changes in version 0.4.3.1-alpha - 2020-01-22
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  This is the first alpha release in the 0.4.3.x series. It includes
  improved support for application integration of onion services, support
  for building in a client-only mode, and newly improved internal
  documentation (online at https://src-ref.docs.torproject.org/tor/). It
  also has numerous other small bugfixes and features, as well as
  improvements to our code's internal organization that should help us
  write better code in the future.
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  o New system requirements:
    - When building Tor, you now need to have Python 3 in order to run
      the integration tests. (Python 2 is officially unsupported
      upstream, as of 1 Jan 2020.) Closes ticket 32608.

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  o Major features (build system):
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    - The relay code can now be disabled using the --disable-module-relay
      configure option. When this option is set, we also disable the
      dirauth module. Closes ticket 32123.
    - When Tor is compiled --disable-module-relay, we also omit the code
      used to act as a directory cache. Closes ticket 32487.
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  o Major features (directory authority, ed25519):
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    - Add support for banning a relay's ed25519 keys in the approved-
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      routers file. This will help us migrate away from RSA keys in the
      future. Previously, only RSA keys could be banned in approved-
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      routers. Resolves ticket 22029. Patch by Neel Chauhan.
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  o Major features (onion service, controller):
    - New control port commands to manage client-side onion service
      authorization credentials. The ONION_CLIENT_AUTH_ADD command adds
      a credential, ONION_CLIENT_AUTH_REMOVE deletes a credential, and
      ONION_CLIENT_AUTH_VIEW lists the credentials. Closes ticket 30381.

  o Major features (onion service, SOCKS5):
    - Introduce a new SocksPort flag, ExtendedErrors, to support more
      detailed error codes in information for applications that support
      them. Closes ticket 30382; implements proposal 304.
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  o Major features (proxy):
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    - In addition to its current supported proxy types (HTTP CONNECT,
      SOCKS4, and SOCKS5), Tor can now make its OR connections through a
      HAProxy server. A new torrc option was added to specify the
      address/port of the server: TCPProxy <protocol> <host>:<port>.
      Currently the only supported protocol for the option is haproxy.
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      Closes ticket 31518. Patch done by Suphanat Chunhapanya (haxxpop).
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  o Major bugfixes (linux seccomp sandbox):
    - Correct how we use libseccomp. Particularly, stop assuming that
      rules are applied in a particular order or that more rules are
      processed after the first match. Neither is the case! In
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      libseccomp <2.4.0 this led to some rules having no effect.
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      libseccomp 2.4.0 changed how rules are generated, leading to a
      different ordering, which in turn led to a fatal crash during
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      startup. Fixes bug 29819; bugfix on 0.2.5.1-alpha. Patch by
      Peter Gerber.
    - Fix crash when reloading logging configuration while the
      experimental sandbox is enabled. Fixes bug 32841; bugfix on
      0.4.1.7. Patch by Peter Gerber.
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  o Major bugfixes (networking):
    - Correctly handle IPv6 addresses in SOCKS5 RESOLVE_PTR requests,
      and accept strings as well as binary addresses. Fixes bug 32315;
      bugfix on 0.3.5.1-alpha.

  o Major bugfixes (onion service):
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    - Report HS circuit failure back into the HS subsystem so we take
      appropriate action with regards to the client introduction point
      failure cache. This improves reachability of onion services, since
      now clients notice failing introduction circuits properly. Fixes
      bug 32020; bugfix on 0.3.2.1-alpha.
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  o Minor feature (configure, build system):
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    - Output a list of enabled/disabled features at the end of the
      configure process in a pleasing way. Closes ticket 31373.
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  o Minor feature (heartbeat, onion service):
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    - Add the DoS INTRODUCE2 defenses counter to the heartbeat DoS
      message. Closes ticket 31371.
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  o Minor features (configuration validation):
    - Configuration validation can now be done by per-module callbacks,
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      rather than a global validation function. This will let us reduce
      the size of config.c and some of its more cumbersome functions.
      Closes ticket 31241.
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  o Minor features (configuration):
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    - If a configured hardware crypto accelerator in AccelName is
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      prefixed with "!", Tor now exits when it cannot be found. Closes
      ticket 32406.
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    - We now use flag-driven logic to warn about obsolete configuration
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      fields, so that we can include their names. In 0.4.2, we used a
      special type, which prevented us from generating good warnings.
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      Implements ticket 32404.

  o Minor features (controller):
    - Add stream isolation data to STREAM event. Closes ticket 19859.
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    - Implement a new GETINFO command to fetch microdescriptor
      consensus. Closes ticket 31684.
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  o Minor features (debugging, directory system):
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    - Don't crash when we find a non-guard with a guard-fraction value
      set. Instead, log a bug warning, in an attempt to figure out how
      this happened. Diagnostic for ticket 32868.
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  o Minor features (defense in depth):
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    - Add additional checks around tor_vasprintf() usage, in case the
      function returns an error. Patch by Tobias Stoeckmann. Fixes
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      ticket 31147.
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  o Minor features (developer tooling):
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    - Remove the 0.2.9.x series branches from git scripts (git-merge-
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      forward.sh, git-pull-all.sh, git-push-all.sh, git-setup-dirs.sh).
      Closes ticket 32772.
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  o Minor features (developer tools):
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    - Add a check_cocci_parse.sh script that checks that new code is
      parseable by Coccinelle. Add an exceptions file for unparseable
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      files, and run the script from travis CI. Closes ticket 31919.
    - Call the check_cocci_parse.sh script from a 'check-cocci' Makefile
      target. Closes ticket 31919.
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    - Add a rename_c_identifiers.py tool to rename a bunch of C
      identifiers at once, and generate a well-formed commit message
      describing the change. This should help with refactoring. Closes
      ticket 32237.
    - Add some scripts in "scripts/coccinelle" to invoke the Coccinelle
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      semantic patching tool with the correct flags. These flags are
      fairly easy to forget, and these scripts should help us use
      Coccinelle more effectively in the future. Closes ticket 31705.
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  o Minor features (Doxygen):
    - Update Doxygen configuration file to a more recent template (from
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      1.8.15). Closes ticket 32110.
    - "make doxygen" now works with out-of-tree builds. Closes
      ticket 32113.
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    - Make sure that doxygen outputs documentation for all of our C
      files. Previously, some were missing @file declarations, causing
      them to be ignored. Closes ticket 32307.
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    - Our "make doxygen" target now respects --enable-fatal-warnings by
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      default, and does not warn about items that are missing
      documentation. To warn about missing documentation, run configure
      with the "--enable-missing-doc-warnings" flag: doing so suspends
      fatal warnings for doxygen. Closes ticket 32385.
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  o Minor features (git scripts):
    - Add TOR_EXTRA_CLONE_ARGS to git-setup-dirs.sh for git clone
      customisation. Closes ticket 32347.
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    - Add git-setup-dirs.sh, which sets up an upstream git repository
      and worktrees for tor maintainers. Closes ticket 29603.
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    - Add TOR_EXTRA_REMOTE_* to git-setup-dirs.sh for a custom extra
      remote. Closes ticket 32347.
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    - Call the check_cocci_parse.sh script from the git commit and push
      hooks. Closes ticket 31919.
    - Make git-push-all.sh skip unchanged branches when pushing to
      upstream. The script already skipped unchanged test branches.
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      Closes ticket 32216.
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    - Make git-setup-dirs.sh create a master symlink in the worktree
      directory. Closes ticket 32347.
    - Skip unmodified source files when doing some existing git hook
      checks. Related to ticket 31919.
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  o Minor features (IPv6, client):
    - Make Tor clients tell dual-stack exits that they prefer IPv6
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      connections. This change is equivalent to setting the PreferIPv6
      flag on SOCKSPorts (and most other listener ports). Tor Browser
      has been setting this flag for some time, and we want to remove a
      client distinguisher at exits. Closes ticket 32637.
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  o Minor features (portability, android):
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    - When building for Android, disable some tests that depend on $HOME
      and/or pwdb, which Android doesn't have. Closes ticket 32825.
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      Patch from Hans-Christoph Steiner.

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  o Minor features (relay modularity):
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    - Split the relay and server pluggable transport config code into
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      separate files in the relay module. Disable this code when the
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      relay module is disabled. Closes part of ticket 32213.
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    - When the relay module is disabled, reject attempts to set the
      ORPort, DirPort, DirCache, BridgeRelay, ExtORPort, or
      ServerTransport* options, rather than ignoring the values of these
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      options. Closes part of ticket 32213.
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  o Minor features (relay):
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    - When the relay module is disabled, change the default config so
      that DirCache is 0, and ClientOnly is 1. Closes ticket 32410.
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  o Minor features (release tools):
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    - Port our ChangeLog formatting and sorting tools to Python 3.
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      Closes ticket 32704.

  o Minor features (testing):
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    - Detect some common failure cases for test_parseconf.sh in
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      src/test/conf_failures. Closes ticket 32451.
    - Allow test_parseconf.sh to test expected log outputs for successful
      configs, as well as failed configs. Closes ticket 32451.
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    - The test_parseconf.sh script now supports result variants for any
      combination of the optional libraries lzma, nss, and zstd. Closes
      ticket 32397.
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  o Minor features (tests, Android):
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    - When running the unit tests on Android, create temporary files in
      a subdirectory of /data/local/tmp. Closes ticket 32172. Based on a
      patch from Hans-Christoph Steiner.
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  o Minor bugfixes (bridges):
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    - Lowercase the configured value of BridgeDistribution before adding
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      it to the descriptor. Fixes bug 32753; bugfix on 0.3.2.3-alpha.
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  o Minor bugfixes (build system):
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    - Fix "make autostyle" for out-of-tree builds. Fixes bug 32370;
      bugfix on 0.4.1.2-alpha.
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  o Minor bugfixes (configuration handling):
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    - Make control_event_conf_changed() take in a config_line_t instead
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      of a smartlist of alternating key/value entries. Fixes bug 31531;
      bugfix on 0.2.3.3-alpha. Patch by Neel Chauhan.
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  o Minor bugfixes (configuration):
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    - Check for multiplication overflow when parsing memory units inside
      configuration. Fixes bug 30920; bugfix on 0.0.9rc1.
    - When dumping the configuration, stop adding a trailing space after
      the option name when there is no option value. This issue only
      affects options that accept an empty value or list. (Most options
      reject empty values, or delete the entire line from the dumped
      options.) Fixes bug 32352; bugfix on 0.0.9pre6.
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    - Avoid changing the user's value of HardwareAccel as stored by
      SAVECONF, when AccelName is set but HardwareAccel is not. Fixes
      bug 32382; bugfix on 0.2.2.1-alpha.
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    - When creating a KeyDirectory with the same location as the
      DataDirectory (not recommended), respect the DataDirectory's
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      group-readable setting if one has not been set for the
      KeyDirectory. Fixes bug 27992; bugfix on 0.3.3.1-alpha.
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  o Minor bugfixes (controller):
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    - In routerstatus_has_changed(), check all the fields that are
      output over the control port. Fixes bug 20218; bugfix
      on 0.1.1.11-alpha
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  o Minor bugfixes (correctness checks):
    - Use GCC/Clang's printf-checking feature to make sure that
      tor_assertf() arguments are correctly typed. Fixes bug 32765;
      bugfix on 0.4.1.1-alpha.

  o Minor bugfixes (developer tools):
    - Allow paths starting with ./ in scripts/add_c_file.py. Fixes bug
      31336; bugfix on 0.4.1.2-alpha.

  o Minor bugfixes (dirauth module):
    - Split the dirauth config code into a separate file in the dirauth
      module. Disable this code when the dirauth module is disabled.
      Closes ticket 32213.
    - When the dirauth module is disabled, reject attempts to set the
      AuthoritativeDir option, rather than ignoring the value of the
      option. Fixes bug 32213; bugfix on 0.3.4.1-alpha.

  o Minor bugfixes (embedded Tor):
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    - When starting Tor any time after the first time in a process,
      register the thread in which it is running as the main thread.
      Previously, we only did this on Windows, which could lead to bugs
      like 23081 on non-Windows platforms. Fixes bug 32884; bugfix
      on 0.3.3.1-alpha.
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  o Minor bugfixes (git scripts):
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    - Avoid sleeping before the last push in git-push-all.sh. Closes
      ticket 32216.
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    - Forward all unrecognised arguments in git-push-all.sh to git push.
      Closes ticket 32216.

  o Minor bugfixes (hidden service v3):
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      instead always query the HS circuit map. This is to avoid sync
      issue with that flag and the map. Fixes bug 32094; bugfix
      on 0.3.2.1-alpha.
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  o Minor bugfixes (logging, crash):
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    - Avoid a possible crash when trying to log a (fatal) assertion
      failure about mismatched magic numbers in configuration objects.
      Fixes bug 32771; bugfix on 0.4.2.1-alpha.
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  o Minor bugfixes (onion service v2):
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    - When sending the INTRO cell for a v2 Onion Service, look at the
      failure cache alongside timeout values to check if the intro point
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      is marked as failed. Previously, we only looked at the relay
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      timeout values. Fixes bug 25568; bugfix on 0.2.7.3-rc. Patch by
      Neel Chauhan.
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  o Minor bugfixes (onion services v3, client):
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    - Properly handle the client rendezvous circuit timeout. Previously
      Tor would sometimes timeout a rendezvous circuit awaiting the
      introduction ACK, and find itself unable to re-establish all
      circuits because the rendezvous circuit timed out too early. Fixes
      bug 32021; bugfix on 0.3.2.1-alpha.
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  o Minor bugfixes (onion services):
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    - In cancel_descriptor_fetches(), use
      connection_list_by_type_purpose() instead of
      connection_list_by_type_state(). Fixes bug 32639; bugfix on
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      0.3.2.1-alpha. Patch by Neel Chauhan.

  o Minor bugfixes (scripts):
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    - Fix update_versions.py for out-of-tree builds. Fixes bug 32371;
      bugfix on 0.4.0.1-alpha.
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  o Minor bugfixes (test):
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    - Use the same code to find the tor binary in all of our test
      scripts. This change makes sure we are always using the coverage
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      binary when coverage is enabled. Fixes bug 32368; bugfix
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      on 0.2.7.3-rc.
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  o Minor bugfixes (testing):
    - Stop ignoring "tor --dump-config" errors in test_parseconf.sh.
      Fixes bug 32468; bugfix on 0.4.2.1-alpha.
    - When TOR_DISABLE_PRACTRACKER is set, do not apply it to the
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      test_practracker.sh script. Doing so caused a test failure. Fixes
      bug 32705; bugfix on 0.4.2.1-alpha.
    - When TOR_DISABLE_PRACTRACKER is set, log a notice to stderr when
      skipping practracker checks. Fixes bug 32705; bugfix
      on 0.4.2.1-alpha.
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  o Minor bugfixes (tests):
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    - Our option-validation tests no longer depend on specially
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      configured non-default, non-passing sets of options. Previously,
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      the tests had been written to assume that options would _not_ be
      set to their defaults, which led to needless complexity and
      verbosity. Fixes bug 32175; bugfix on 0.2.8.1-alpha.
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  o Minor bugfixes (windows service):
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    - Initialize the publish/subscribe system when running as a windows
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      service. Fixes bug 32778; bugfix on 0.4.1.1-alpha.
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  o Deprecated features:
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    - Deprecate the ClientAutoIPv6ORPort option. This option was not
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      true "Happy Eyeballs", and often failed on connections that
      weren't reliably dual-stack. Closes ticket 32942. Patch by
      Neel Chauhan.
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  o Documentation:
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    - Provide a quickstart guide for a Circuit Padding Framework, and
      documentation for researchers to implement and study circuit
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      padding machines. Closes ticket 28804.
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    - Add documentation in 'HelpfulTools.md' to describe how to build a
      tag file. Closes ticket 32779.
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    - Create a high-level description of the long-term software
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      architecture goals. Closes ticket 32206.
    - Describe the --dump-config command in the manual page. Closes
      ticket 32467.
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    - Unite coding advice from this_not_that.md in torguts repo into our
      coding standards document. Resolves ticket 31853.

  o Removed features:
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    - Our Doxygen configuration no longer generates LaTeX output. The
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      reference manual produced by doing this was over 4000 pages long,
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      and generally unusable. Closes ticket 32099.
    - The option "TestingEstimatedDescriptorPropagationTime" is now
      marked as obsolete. It has had no effect since 0.3.0.7, when
      clients stopped rejecting consensuses "from the future". Closes
      ticket 32807.
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    - We no longer support consensus methods before method 28; these
      methods were only used by authorities running versions of Tor that
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      are now at end-of-life. In effect, this means that clients,
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      relays, and authorities now assume that authorities will be
      running version 0.3.5.x or later. Closes ticket 32695.

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  o Testing:
    - Add more test cases for tor's UTF-8 validation function. Also,
      check the arguments passed to the function for consistency. Closes
      ticket 32845.
    - Improve test coverage for relay and dirauth config code, focusing
      on option validation and normalization. Closes ticket 32213.
    - Improve the consistency of test_parseconf.sh output, and run all
      the tests, even if one fails. Closes ticket 32213.
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    - Re-enable the Travis CI macOS Chutney build, but don't let it
      prevent the Travis job from finishing. (The Travis macOS jobs are
      slow, so we don't want to have it delay the whole CI process.)
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      Closes ticket 32629.
    - Run the practracker unit tests in the pre-commit git hook. Closes
      ticket 32609.
    - Turn off Tor's Sandbox in Chutney jobs, and run those jobs on
      Ubuntu Bionic. Turning off the Sandbox is a work-around, until we
      fix the sandbox errors in 32722. Closes ticket 32240.

  o Code simplification and refactoring (channel):
    - Channel layer had a variable length cell handler that was not used
      and thus removed. Closes ticket 32892.

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  o Code simplification and refactoring (configuration):
    - Immutability is now implemented as a flag on individual
      configuration options rather than as part of the option-transition
      checking code. Closes ticket 32344.
    - Instead of keeping a list of configuration options to check for
      relative paths, check all the options whose type is "FILENAME".
      Solves part of ticket 32339.
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    - Our default log (which ordinarily sends NOTICE-level messages to
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      standard output) is now handled in a more logical manner.
      Previously, we replaced the configured log options if they were
      empty. Now, we interpret an empty set of log options as meaning
      "use the default log". Closes ticket 31999.
    - Remove some unused arguments from the options_validate() function,
      to simplify our code and tests. Closes ticket 32187.
    - Simplify the options_validate() code so that it looks at the
      default options directly, rather than taking default options as an
      argument. This change lets us simplify its interface. Closes
      ticket 32185.
    - Use our new configuration architecture to move most authority-
      related options to the directory authority module. Closes
      ticket 32806.
    - When parsing the command line, handle options that determine our
      "quiet level" and our mode of operation (e.g., --dump-config and
      so on) all in one table. Closes ticket 32003.

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  o Code simplification and refactoring (controller):
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    - Create a new abstraction for formatting control protocol reply
      lines based on key-value pairs. Refactor some existing control
      protocol code to take advantage of this. Closes ticket 30984.
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    - Create a helper function that can fetch network status or
      microdesc consensuses. Closes ticket 31684.

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  o Code simplification and refactoring (dirauth modularization):
    - Remove the last remaining HAVE_MODULE_DIRAUTH inside a function.
      Closes ticket 32163.
    - Replace some confusing identifiers in process_descs.c. Closes
      ticket 29826.
    - Simplify some relay and dirauth config code. Closes ticket 32213.

  o Code simplification and refactoring (misc):
    - Make all the structs we declare follow the same naming convention
      of ending with "_t". Closes ticket 32415.
    - Move and rename some configuration-related code for clarity.
      Closes ticket 32304.
    - Our include.am files are now broken up by subdirectory.
      Previously, src/core/include.am covered all of the subdirectories
      in "core", "feature", and "app". Closes ticket 32137.
    - Remove underused NS*() macros from test code: they make our tests
      more confusing, especially for code-formatting tools. Closes
      ticket 32887.

  o Code simplification and refactoring (relay modularization):
    - Disable relay_periodic when the relay module is disabled. Closes
      ticket 32244.
    - Disable relay_sys when the relay module is disabled. Closes
      ticket 32245.

  o Code simplification and refactoring (tool support):
    - Add numerous missing dependencies to our include files, so that
      they can be included in different reasonable orders and still
      compile. Addresses part of ticket 32764.
    - Fix some parts of our code that were difficult for Coccinelle to
      parse. Related to ticket 31705.
    - Fix some small issues in our code that prevented automatic
      formatting tools from working. Addresses part of ticket 32764.

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  o Documentation (manpage):
    - Alphabetize the Client Options section of the tor manpage. Closes
      ticket 32846.
    - Alphabetize the General Options section of the tor manpage. Closes
      ticket 32708.
    - In the tor(1) manpage, reword and improve formatting of the
      COMMAND-LINE OPTIONS and DESCRIPTION sections. Closes ticket
      32277. Based on work by Swati Thacker as part of Google Season
      of Docs.
    - In the tor(1) manpage, reword and improve formatting of the FILES,
      SEE ALSO, and BUGS sections. Closes ticket 32176. Based on work by
      Swati Thacker as part of Google Season of Docs.

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  o Testing (circuit, EWMA):
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    - Add unit tests for circuitmux and EWMA subsystems. Closes
      ticket 32196.
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  o Testing (continuous integration):
    - Use zstd in our Travis Linux builds. Closes ticket 32242.


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Changes in version 0.4.2.5 - 2019-12-09
  This is the first stable release in the 0.4.2.x series. This series
  improves reliability and stability, and includes several stability and
  correctness improvements for onion services. It also fixes many smaller
  bugs present in previous series.

  Per our support policy, we will support the 0.4.2.x series for nine
  months, or until three months after the release of a stable 0.4.3.x:
  whichever is longer. If you need longer-term support, please stick
  with 0.3.5.x, which will we plan to support until Feb 2022.

  Per our support policy, we will support the 0.4.2.x series for nine
  months, or until three months after the release of a stable 0.4.3.x:
  whichever is longer. If you need longer-term support, please stick
  with 0.3.5.x, which will we plan to support until Feb 2022.

  Below are the changes since 0.4.1.4-rc. For a complete list of changes
  since 0.4.1.5, see the ReleaseNotes file.

  o Minor features (geoip):
    - Update geoip and geoip6 to the December 3 2019 Maxmind GeoLite2
      Country database. Closes ticket 32685.

  o Testing:
    - Require C99 standards-conforming code in Travis CI, but allow GNU
      gcc extensions. Also activates clang's -Wtypedef-redefinition
      warnings. Build some jobs with -std=gnu99, and some jobs without.
      Closes ticket 32500.


Changes in version 0.4.1.7 - 2019-12-09
  This release backports several bugfixes to improve stability and
  correctness.  Anyone experiencing build problems or crashes with 0.4.1.6,
  including all relays relying on AccountingMax, should upgrade.

  o Major features (directory authorities, backport from 0.4.2.2-alpha):
    - Directory authorities now reject relays running all currently
      deprecated release series. The currently supported release series
      are: 0.2.9, 0.3.5, 0.4.0, 0.4.1, and 0.4.2. Closes ticket 31549.

  o Major bugfixes (embedded Tor, backport from 0.4.2.2-alpha):
    - Avoid a possible crash when restarting Tor in embedded mode and
      enabling a different set of publish/subscribe messages. Fixes bug
      31898; bugfix on 0.4.1.1-alpha.

  o Major bugfixes (relay, backport from 0.4.2.3-alpha):
    - Relays now respect their AccountingMax bandwidth again. When
      relays entered "soft" hibernation (which typically starts when
      we've hit 90% of our AccountingMax), we had stopped checking
      whether we should enter hard hibernation. Soft hibernation refuses
      new connections and new circuits, but the existing circuits can
      continue, meaning that relays could have exceeded their configured
      AccountingMax. Fixes bug 32108; bugfix on 0.4.0.1-alpha.

  o Major bugfixes (torrc parsing, backport from 0.4.2.2-alpha):
    - Stop ignoring torrc options after an %include directive, when the
      included directory ends with a file that does not contain any
      config options (but does contain comments or whitespace). Fixes
      bug 31408; bugfix on 0.3.1.1-alpha.

  o Major bugfixes (v3 onion services, backport from 0.4.2.3-alpha):
    - Onion services now always use the exact number of intro points
      configured with the HiddenServiceNumIntroductionPoints option (or
      fewer if nodes are excluded). Before, a service could sometimes
      pick more intro points than configured. Fixes bug 31548; bugfix
      on 0.3.2.1-alpha.

  o Minor features (continuous integration, backport from 0.4.2.2-alpha):
    - When building on Appveyor and Travis, pass the "-k" flag to make,
      so that we are informed of all compilation failures, not just the
      first one or two. Closes ticket 31372.

  o Minor features (geoip, backport from 0.4.2.5):
    - Update geoip and geoip6 to the December 3 2019 Maxmind GeoLite2
      Country database. Closes ticket 32685.

  o Minor bugfixes (Appveyor CI, backport from 0.4.2.2-alpha):
    - Avoid spurious errors when Appveyor CI fails before the install step.
      Fixes bug 31884; bugfix on 0.3.4.2-alpha.

  o Minor bugfixes (client, onion service v3, backport from 0.4.2.4-rc):
    - Fix a BUG() assertion that occurs within a very small race window
      between when a client intro circuit opens and when its descriptor
      gets cleaned up from the cache. The circuit is now closed early,
      which will trigger a re-fetch of the descriptor and continue the
      connection. Fixes bug 28970; bugfix on 0.3.2.1-alpha.

  o Minor bugfixes (connections, backport from 0.4.2.3-rc):
    - Avoid trying to read data from closed connections, which can cause
      needless loops in Libevent and infinite loops in Shadow. Fixes bug
      30344; bugfix on 0.1.1.1-alpha.

  o Minor bugfixes (error handling, backport from 0.4.2.1-alpha):
    - On abort, try harder to flush the output buffers of log messages.
      On some platforms (macOS), log messages could be discarded when
      the process terminates. Fixes bug 31571; bugfix on 0.3.5.1-alpha.
    - Report the tor version whenever an assertion fails. Previously, we
      only reported the Tor version on some crashes, and some non-fatal
      assertions. Fixes bug 31571; bugfix on 0.3.5.1-alpha.
    - When tor aborts due to an error, close log file descriptors before
      aborting. Closing the logs makes some OSes flush log file buffers,
      rather than deleting buffered log lines. Fixes bug 31594; bugfix
      on 0.2.5.2-alpha.

  o Minor bugfixes (logging, backport from 0.4.2.2-alpha):
    - Add a missing check for HAVE_PTHREAD_H, because the backtrace code
      uses mutexes. Fixes bug 31614; bugfix on 0.2.5.2-alpha.
    - Disable backtrace signal handlers when shutting down tor. Fixes
      bug 31614; bugfix on 0.2.5.2-alpha.
    - Rate-limit our the logging message about the obsolete .exit
      notation. Previously, there was no limit on this warning, which
      could potentially be triggered many times by a hostile website.
      Fixes bug 31466; bugfix on 0.2.2.1-alpha.

  o Minor bugfixes (logging, protocol violations, backport from 0.4.2.2-alpha):
    - Do not log a nonfatal assertion failure when receiving a VERSIONS
      cell on a connection using the obsolete v1 link protocol. Log a
      protocol_warn instead. Fixes bug 31107; bugfix on 0.2.4.4-alpha.

  o Minor bugfixes (mainloop, periodic events, in-process API, backport from 0.4.2.3-alpha):
    - Reset the periodic events' "enabled" flag when Tor is shut down
      cleanly. Previously, this flag was left on, which caused periodic
      events not to be re-enabled when Tor was relaunched in-process
      with tor_api.h after a shutdown. Fixes bug 32058; bugfix
      on 0.3.3.1-alpha.

  o Minor bugfixes (multithreading, backport from 0.4.2.2-alpha):
    - Avoid some undefined behaviour when freeing mutexes. Fixes bug
      31736; bugfix on 0.0.7.

  o Minor bugfixes (process management, backport from 0.4.2.3-alpha):
    - Remove overly strict assertions that triggered when a pluggable
      transport failed to launch. Fixes bug 31091; bugfix
      on 0.4.0.1-alpha.
    - Remove an assertion in the Unix process backend. This assertion
      would trigger when we failed to find the executable for a child
      process. Fixes bug 31810; bugfix on 0.4.0.1-alpha.

  o Minor bugfixes (relay, backport from 0.4.2.2-alpha):
    - Avoid crashing when starting with a corrupt keys directory where
      the old ntor key and the new ntor key are identical. Fixes bug
      30916; bugfix on 0.2.4.8-alpha.

  o Minor bugfixes (testing, backport from 0.4.2.3-alpha):
    - When testing port rebinding, don't busy-wait for tor to log.
      Instead, actually sleep for a short time before polling again.
      Also improve the formatting of control commands and log messages.
      Fixes bug 31837; bugfix on 0.3.5.1-alpha.

  o Minor bugfixes (tests, SunOS, backport from 0.4.2.2-alpha):
    - Avoid a map_anon_nofork test failure due to a signed/unsigned
      integer comparison. Fixes bug 31897; bugfix on 0.4.1.1-alpha.

  o Minor bugfixes (tls, logging, backport from 0.4.2.3-alpha):
    - Log bugs about the TLS read buffer's length only once, rather than
      filling the logs with similar warnings. Fixes bug 31939; bugfix
      on 0.3.0.4-rc.

  o Documentation (backport from 0.4.2.2-alpha):
    - Explain why we can't destroy the backtrace buffer mutex. Explain
      why we don't need to destroy the log mutex. Closes ticket 31736.

  o Testing (continuous integration, backport from 0.4.2.3-alpha):
    - Disable all but one Travis CI macOS build, to mitigate slow
      scheduling of Travis macOS jobs. Closes ticket 32177.
    - Run the chutney IPv6 networks as part of Travis CI. Closes
      ticket 30860.
    - Simplify the Travis CI build matrix, and optimise for build time.
      Closes ticket 31859.
    - Use Windows Server 2019 instead of Windows Server 2016 in our
      Appveyor builds. Closes ticket 32086.

  o Testing (continuous integration, backport from 0.4.2.4-rc):
    - In Travis, use Xcode 11.2 on macOS 10.14. Closes ticket 32241.
    - Use Ubuntu Bionic images for our Travis CI builds, so we can get a
      recent version of coccinelle. But leave chutney on Ubuntu Trusty,
      until we can fix some Bionic permissions issues (see ticket
      32240). Related to ticket 31919.
    - Install the mingw OpenSSL package in Appveyor. This makes sure
      that the OpenSSL headers and libraries match in Tor's Appveyor
      builds. (This bug was triggered by an Appveyor image update.)
      Fixes bug 32449; bugfix on 0.3.5.6-rc.

  o Testing (continuous integration, backport from 0.4.2.5):
    - Require C99 standards-conforming code in Travis CI, but allow GNU gcc
      extensions. Also activates clang's -Wtypedef-redefinition warnings.
      Build some jobs with -std=gnu99, and some jobs without.
      Closes ticket 32500.


Changes in version 0.4.0.6 - 2019-12-09
  This is the second stable release in the 0.4.0.x series. This release
  backports several bugfixes to improve stability and correctness.  Anyone
  experiencing build problems or crashes with 0.4.0.5, including all relays
  relying on AccountingMax, should upgrade.

  Note that, per our support policy, support for the 0.4.0.x series will end
  on 2 Feb 2020.  Anyone still running 0.4.0.x should plan to upgrade to the
  latest stable release, or downgrade to 0.3.5.x, which will get long-term
  support until 1 Feb 2022.

  o Directory authority changes (backport from 0.4.1.5):
    - The directory authority "dizum" has a new IP address. Closes
      ticket 31406.

  o Major bugfixes (bridges, backport from 0.4.1.2-alpha):
    - Consider our directory information to have changed when our list
      of bridges changes. Previously, Tor would not re-compute the
      status of its directory information when bridges changed, and
      therefore would not realize that it was no longer able to build
      circuits. Fixes part of bug 29875.
    - Do not count previously configured working bridges towards our
      total of working bridges. Previously, when Tor's list of bridges
      changed, it would think that the old bridges were still usable,
      and delay fetching router descriptors for the new ones. Fixes part
      of bug 29875; bugfix on 0.3.0.1-alpha.

  o Major bugfixes (circuit build, guard, backport from 0.4.1.4-rc):
    - When considering upgrading circuits from "waiting for guard" to
      "open", always ignore circuits that are marked for close. Otherwise,
      we can end up in the situation where a subsystem is notified that
      a closing circuit has just opened, leading to undesirable
      behavior. Fixes bug 30871; bugfix on 0.3.0.1-alpha.

  o Major bugfixes (Onion service reachability, backport from 0.4.1.3-alpha):
    - Properly clean up the introduction point map when circuits change
      purpose from onion service circuits to pathbias, measurement, or
      other circuit types. This should fix some service-side instances
      of introduction point failure. Fixes bug 29034; bugfix
      on 0.3.2.1-alpha.

  o Major bugfixes (onion service v3, backport from 0.4.1.1-alpha):
    - Fix an unreachable bug in which an introduction point could try to
      send an INTRODUCE_ACK with a status code that Trunnel would refuse
      to encode, leading the relay to assert(). We've consolidated the
      ABI values into Trunnel now. Fixes bug 30454; bugfix
      on 0.3.0.1-alpha.
    - Clients can now handle unknown status codes from INTRODUCE_ACK
      cells. (The NACK behavior will stay the same.) This will allow us
      to extend status codes in the future without breaking the normal
      client behavior. Fixes another part of bug 30454; bugfix
      on 0.3.0.1-alpha.

  o Major bugfixes (relay, backport from 0.4.2.3-alpha):
    - Relays now respect their AccountingMax bandwidth again. When
      relays entered "soft" hibernation (which typically starts when
      we've hit 90% of our AccountingMax), we had stopped checking
      whether we should enter hard hibernation. Soft hibernation refuses
      new connections and new circuits, but the existing circuits can
      continue, meaning that relays could have exceeded their configured
      AccountingMax. Fixes bug 32108; bugfix on 0.4.0.1-alpha.

  o Major bugfixes (torrc parsing, backport from 0.4.2.2-alpha):
    - Stop ignoring torrc options after an %include directive, when the
      included directory ends with a file that does not contain any
      config options (but does contain comments or whitespace). Fixes
      bug 31408; bugfix on 0.3.1.1-alpha.

  o Major bugfixes (v3 onion services, backport from 0.4.2.3-alpha):
    - Onion services now always use the exact number of intro points
      configured with the HiddenServiceNumIntroductionPoints option (or
      fewer if nodes are excluded). Before, a service could sometimes
      pick more intro points than configured. Fixes bug 31548; bugfix
      on 0.3.2.1-alpha.

  o Minor features (compile-time modules, backport from version 0.4.1.1-alpha):
    - Add a "--list-modules" command to print a list of which compile-
      time modules are enabled. Closes ticket 30452.

  o Minor features (continuous integration, backport from 0.4.1.1-alpha):
    - Remove sudo configuration lines from .travis.yml as they are no
      longer needed with current Travis build environment. Resolves
      issue 30213.

  o Minor features (continuous integration, backport from 0.4.1.4-rc):
    - Our Travis configuration now uses Chutney to run some network
      integration tests automatically. Closes ticket 29280.

  o Minor features (continuous integration, backport from 0.4.2.2-alpha):
    - When building on Appveyor and Travis, pass the "-k" flag to make,
      so that we are informed of all compilation failures, not just the
      first one or two. Closes ticket 31372.

  o Minor features (fallback directory list, backport from 0.4.1.4-rc):
    - Replace the 157 fallbacks originally introduced in Tor 0.3.5.6-rc
      in December 2018 (of which ~122 were still functional), with a
      list of 148 fallbacks (70 new, 78 existing, 79 removed) generated
      in June 2019. Closes ticket 28795.

  o Minor features (geoip, backport from 0.4.2.5):
    - Update geoip and geoip6 to the December 3 2019 Maxmind GeoLite2
      Country database. Closes ticket 32685.

  o Minor features (stem tests, backport from 0.4.2.1-alpha):
    - Change "make test-stem" so it only runs the stem tests that use
      tor. This change makes test-stem faster and more reliable. Closes
      ticket 31554.

  o Minor bugfixes (Appveyor CI, backport from 0.4.2.2-alpha):
    - Avoid spurious errors when Appveyor CI fails before the install step.
      Fixes bug 31884; bugfix on 0.3.4.2-alpha.

  o Minor bugfixes (build system, backport form 0.4.2.1-alpha):
    - Do not include the deprecated <sys/sysctl.h> on Linux or Windows
      systems. Fixes bug 31673; bugfix on 0.2.5.4-alpha.

  o Minor bugfixes (circuit isolation, backport from 0.4.1.3-alpha):
    - Fix a logic error that prevented the SessionGroup sub-option from
      being accepted. Fixes bug 22619; bugfix on 0.2.7.2-alpha.

  o Minor bugfixes (circuit padding, backport from 0.4.1.4-rc):
    - On relays, properly check that a padding machine is absent before
      logging a warning about it being absent. Fixes bug 30649; bugfix
      on 0.4.0.1-alpha.

  o Minor bugfixes (client, onion service v3, backport from 0.4.2.4-rc):
    - Fix a BUG() assertion that occurs within a very small race window
      between when a client intro circuit opens and when its descriptor
      gets cleaned up from the cache. The circuit is now closed early,
      which will trigger a re-fetch of the descriptor and continue the
      connection. Fixes bug 28970; bugfix on 0.3.2.1-alpha.

  o Minor bugfixes (clock skew detection, backport from 0.4.1.5):
    - Don't believe clock skew results from NETINFO cells that appear to
      arrive before we sent the VERSIONS cells they are responding to.
      Previously, we would accept them up to 3 minutes "in the past".
      Fixes bug 31343; bugfix on 0.2.4.4-alpha.

  o Minor bugfixes (compilation warning, backport from 0.4.1.5):
    - Fix a compilation warning on Windows about casting a function
      pointer for GetTickCount64(). Fixes bug 31374; bugfix
      on 0.2.9.1-alpha.

  o Minor bugfixes (compilation, backport from 0.4.1.5):
    - Avoid using labs() on time_t, which can cause compilation warnings
      on 64-bit Windows builds. Fixes bug 31343; bugfix on 0.2.4.4-alpha.

  o Minor bugfixes (compilation, backport from 0.4.2.1-alpha):
    - Suppress spurious float-conversion warnings from GCC when calling
      floating-point classifier functions on FreeBSD. Fixes part of bug
      31687; bugfix on 0.3.1.5-alpha.

  o Minor bugfixes (compilation, unusual configurations, backport from 0.4.1.1-alpha):
    - Avoid failures when building with the ALL_BUGS_ARE_FATAL option
      due to missing declarations of abort(), and prevent other such
      failures in the future. Fixes bug 30189; bugfix on 0.3.4.1-alpha.