[tor-talk] New release: Tor 0.4.1.2-alpha

[Nick Mathewson]

There's a new alpha Tor release! Because it's an alpha, you should
only run it if you're ready to find more bugs than usual, and report
them on trac.torproject.org.

The source code is available from
https://www.torproject.org/download/tor/ ;  if you build Tor from
source, why not give it a try? And if you don't build Tor from source,
packages should be ready over the coming days, with a Tor Browser
alpha release likely some time next week.

Here's what's new:

Changes in version 0.4.1.2-alpha - 2019-06-06
  Tor 0.4.1.2-alpha resolves numerous bugs--some of them from the
  previous alpha, and some much older. It also contains minor testing
  improvements, and an improvement to the security of our authenticated
  SENDME implementation.

  o Major bugfixes (bridges):
    - 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 (flow control, SENDME):
    - Decrement the stream-level package window after packaging a cell.
      Previously, it was done inside a log_debug() call, meaning that if
      debug logs were not enabled, the decrement would never happen, and
      thus the window would be out of sync with the other end point.
      Fixes bug 30628; bugfix on 0.4.1.1-alpha.

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

  o Minor features (authenticated SENDME):
    - Ensure that there is enough randomness on every circuit to prevent
      an attacker from successfully predicting the hashes they will need
      to include in authenticated SENDME cells. At a random interval, if
      we have not sent randomness already, we now leave some extra space
      at the end of a cell that we can fill with random bytes. Closes
      ticket 26846.

  o Minor features (continuous integration):
    - When running coverage builds on Travis, we now set
      TOR_TEST_RNG_SEED, to avoid RNG-based coverage differences. Part
      of ticket 28878.

  o Minor features (maintenance):
    - Add a new "make autostyle" target that developers can use to apply
      all automatic Tor style and consistency conversions to the
      codebase. Closes ticket 30539.

  o Minor features (testing):
    - The circuitpadding tests now use a reproducible RNG implementation,
      so that if a test fails, we can learn why. Part of ticket 28878.
    - Tor's tests now support an environment variable, TOR_TEST_RNG_SEED,
      to set the RNG seed for tests that use a reproducible RNG. Part of
      ticket 28878.
    - When running tests in coverage mode, take additional care to make
      our coverage deterministic, so that we can accurately track
      changes in code coverage. Closes ticket 30519.

  o Minor bugfixes (configuration, proxies):
    - Fix a bug that prevented us from supporting SOCKS5 proxies that
      want authentication along with configured (but unused!)
      ClientTransportPlugins. Fixes bug 29670; bugfix on 0.2.6.1-alpha.

  o Minor bugfixes (controller):
    - POSTDESCRIPTOR requests should work again. Previously, they were
      broken if a "purpose=" flag was specified. Fixes bug 30580; bugfix
      on 0.4.1.1-alpha.
    - Repair the HSFETCH command so that it works again. Previously, it
      expected a body when it shouldn't have. Fixes bug 30646; bugfix
      on 0.4.1.1-alpha.

  o Minor bugfixes (developer tooling):
    - Fix pre-push hook to allow fixup and squash commits when pushing
      to non-upstream git remote. Fixes bug 30286; bugfix
      on 0.4.0.1-alpha.

  o Minor bugfixes (directory authority):
    - Move the "bandwidth-file-headers" line in directory authority
      votes so that it conforms to dir-spec.txt. Fixes bug 30316; bugfix
      on 0.3.5.1-alpha.

  o Minor bugfixes (NetBSD):
    - Fix usage of minherit() on NetBSD and other platforms that define
      MAP_INHERIT_{ZERO,NONE} instead of INHERIT_{ZERO,NONE}. Fixes bug
      30614; bugfix on 0.4.0.2-alpha. Patch from Taylor Campbell.

  o Minor bugfixes (out-of-memory handler):
    - When purging the DNS cache because of an out-of-memory condition,
      try purging just the older entries at first. Previously, we would
      always purge the whole thing. Fixes bug 29617; bugfix
      on 0.3.5.1-alpha.

  o Minor bugfixes (portability):
    - Avoid crashing in our tor_vasprintf() implementation on systems
      that define neither vasprintf() nor _vscprintf(). (This bug has
      been here long enough that we question whether people are running
      Tor on such systems, but we're applying the fix out of caution.)
      Fixes bug 30561; bugfix on 0.2.8.2-alpha. Found and fixed by
      Tobias Stoeckmann.

  o Minor bugfixes (shutdown, libevent, memory safety):
    - Avoid use-after-free bugs when shutting down, by making sure that
      we shut down libevent only after shutting down all of its users.
      We believe these are harmless in practice, since they only occur
      on the shutdown path, and do not involve any attacker-controlled
      data. Fixes bug 30629; bugfix on 0.4.1.1-alpha.

  o Minor bugfixes (static analysis):
    - Fix several spurious Coverity warnings about the unit tests, to
      lower our chances of missing real warnings in the future. Fixes
      bug 30150; bugfix on 0.3.5.1-alpha and various other Tor versions.

  o Testing:
    - Specify torrc paths (with empty files) when launching tor in
      integration tests; refrain from reading user and system torrcs.
      Resolves issue 29702.