042: copy changelog into release notes

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 0.4.2.8 - 2020-07-09

  Tor 0.4.2.8 backports various fixes from later releases, including

  several that affect usability and portability.

  This release also fixes TROVE-2020-001, a medium-severity denial of

  service vulnerability affecting all versions of Tor when compiled with

  the NSS encryption library. (This is not the default configuration.)

  Using this vulnerability, an attacker could cause an affected Tor

  instance to crash remotely. This issue is also tracked as CVE-2020-

  15572. Anybody running a version of Tor built with the NSS library

  should upgrade to 0.3.5.11, 0.4.2.8, 0.4.3.6, or 0.4.4.2-alpha

  or later.

  o Major bugfixes (NSS, security, backport from 0.4.4.2-alpha):

    - Fix a crash due to an out-of-bound memory access when Tor is

      compiled with NSS support. Fixes bug 33119; bugfix on

      0.3.5.1-alpha. This issue is also tracked as TROVE-2020-001

      and CVE-2020-15572.

  o Major bugfixes (DoS defenses, bridges, pluggable transport, backport from 0.4.3.4-rc):

    - Fix a bug that was preventing DoS defenses from running on bridges

      with a pluggable transport. Previously, the DoS subsystem was not

      given the transport name of the client connection, thus failed to

      find the GeoIP cache entry for that client address. Fixes bug

      33491; bugfix on 0.3.3.2-alpha.

  o Minor feature (sendme, flow control, backport form 0.4.3.4-rc):

    - Default to sending SENDME version 1 cells. (Clients are already

      sending these, because of a consensus parameter telling them to do

      so: this change only affects what clients would do if the

      consensus didn't contain a recommendation.) Closes ticket 33623.

  o Minor features (diagnostic, backport from 0.4.3.3-alpha):

    - Improve assertions and add some memory-poisoning code to try to

      track down possible causes of a rare crash (32564) in the EWMA

      code. Closes ticket 33290.

  o Minor features (testing, backport from 0.4.3.4-rc):

    - The unit tests now support a "TOR_SKIP_TESTCASES" environment

      variable to specify a list of space-separated test cases that

      should not be executed. We will use this to disable certain tests

      that are failing on Appveyor because of mismatched OpenSSL

      libraries. Part of ticket 33643.

  o Minor bugfix (CI, Windows, backport from 0.4.4.2-alpha):

    - Use the correct 64-bit printf format when compiling with MINGW on

      Appveyor. Fixes bug 40026; bugfix on 0.3.5.5-alpha.

  o Minor bugfix (relay, configuration, backport from 0.4.3.3-alpha):

    - Warn if the ContactInfo field is not set, and tell the relay

      operator that not having a ContactInfo field set might cause their

      relay to get rejected in the future. Fixes bug 33361; bugfix

      on 0.1.1.10-alpha.

  o Minor bugfixes (client performance, backport from 0.4.4.1-alpha):

    - Resume use of preemptively-built circuits when UseEntryGuards is set

      to 0. We accidentally disabled this feature with that config

      setting, leading to slower load times. Fixes bug 34303; bugfix

      on 0.3.3.2-alpha.

  o Minor bugfixes (compiler compatibility, backport from 0.4.3.5):

    - Avoid compiler warnings from Clang 10 related to the use of GCC-

      style "/* falls through */" comments. Both Clang and GCC allow

      __attribute__((fallthrough)) instead, so that's what we're using

      now. Fixes bug 34078; bugfix on 0.3.1.3-alpha.

    - Fix compilation warnings with GCC 10.0.1. Fixes bug 34077; bugfix

      on 0.4.0.3-alpha.

  o Minor bugfixes (compiler warnings, backport from 0.4.4.2-alpha):

    - Fix a compiler warning on platforms with 32-bit time_t values.

      Fixes bug 40028; bugfix on 0.3.2.8-rc.

  o Minor bugfixes (controller protocol, backport from 0.4.3.2-alpha):

    - When receiving "ACTIVE" or "DORMANT" signals on the control port,

      report them as SIGNAL events. Previously we would log a bug

      warning. Fixes bug 33104; bugfix on 0.4.0.1-alpha.

  o Minor bugfixes (embedded Tor, backport from 0.4.3.1-alpha):

    - 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.

  o Minor bugfixes (key portability, backport from 0.4.3.4-rc):

    - When reading PEM-encoded key data, tolerate CRLF line-endings even

      if we are not running on Windows. Previously, non-Windows hosts

      would reject these line-endings in certain positions, making

      certain key files hard to move from one host to another. Fixes bug

      33032; bugfix on 0.3.5.1-alpha.

  o Minor bugfixes (logging, backport from 0.4.3.2-rc):

    - When logging a bug, do not say "Future instances of this warning

      will be silenced" unless we are actually going to silence them.

      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 (logging, backport from 0.4.3.4-rc):

    - Flush stderr, stdout, and file logs during shutdown, if supported

      by the OS. This change helps make sure that any final logs are

      recorded. Fixes bug 33087; bugfix on 0.4.1.6.

  o Minor bugfixes (logging, backport from 0.4.4.2-alpha):

    - Downgrade a noisy log message that could occur naturally when

      receiving an extrainfo document that we no longer want. Fixes bug

      16016; bugfix on 0.2.6.3-alpha.

  o Minor bugfixes (onion service v3, client, backport from 0.4.3.3-alpha):

    - Remove a BUG() warning that would cause a stack trace if an onion

      service descriptor was freed while we were waiting for a

      rendezvous circuit to complete. Fixes bug 28992; bugfix

      on 0.3.2.1-alpha.

  o Testing (CI, backport from 0.4.3.4-rc):

    - In our Appveyor Windows CI, copy required DLLs to test and app

      directories, before running tor's tests. This ensures that tor.exe

      and test*.exe use the correct version of each DLL. This fix is not

      required, but we hope it will avoid DLL search issues in future.

      Fixes bug 33673; bugfix on 0.3.4.2-alpha.

    - On Appveyor, skip the crypto/openssl_version test, which is

      failing because of a mismatched library installation. Fix

      for 33643.

Changes in version 0.4.2.7 - 2020-03-18

  This is the third stable release in the 0.4.2.x series. It backports

  numerous fixes from later releases, including a fix for TROVE-2020-