[tor-talk] Tor is released.

Nick Mathewson nickm at torproject.org
Sun Mar 23 03:48:28 UTC 2014

Changes in version - 2014-03-23
  Tor includes all the fixes from It contains
  two new anti-DoS features for Tor relays, resolves a bug that kept
  SOCKS5 support for IPv6 from working, fixes several annoying usability
  issues for bridge users, and removes more old code for unused
  directory formats.

  The Tor 0.2.5.x release series is now in patch-freeze: no feature
  patches not already written will be considered for inclusion in 0.2.5.x.

  The source is ready today; packages should be ready in the next several days.

  (I'm trying to take some load off of Roger's shoulders by doing
releases myself.  This means that the signatures on the release are be
made with my PGP key, not Roger's.  Please don't freak out.)


  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 and improved in, 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.
    - Decrease the lower limit of MaxMemInQueues to 256 MBytes (but leave
      the default at 8GBytes), to better support Raspberry Pi users. Fixes
      bug 9686; bugfix on

  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.

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

  o Minor bugfixes (new since, also in
    - 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.
    - 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 Patch from Dana Koch.

  o Minor bugfixes (client):
    - 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
    - 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
    - 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
    - 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
    - Fix connections to IPv6 addresses over SOCKS5. Previously, we were
      generating incorrect SOCKS5 responses, and confusing client
      applications. Fixes bug 10987; bugfix on

  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
    - Non-exit relays no longer launch mock DNS requests to check for
      DNS hijacking. This has been unnecessary since, when
      non-exit relays stopped servicing DNS requests. Fixes bug 965;
      bugfix on Patch from Matt Pagan.
    - Bridges now report complete directory request statistics. Related
      to bug 5824; bugfix on
    - Bridges now never collect statistics that were designed for
      relays. Fixes bug 5824; bugfix on
    - Stop giving annoying warning messages when we decide not to launch
      a pluggable transport proxy that we don't need (because there are
      no bridges configured to use it). Resolves ticket 5018; bugfix
    - 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 (backtrace support):
    - Support automatic backtraces on more platforms by using the
      "-fasynchronous-unwind-tables" compiler option. This option is
      needed for platforms like 32-bit Intel where "-fomit-frame-pointer"
      is on by default and table generation is not. This doesn't yet
      add Windows support; only Linux, OSX, and some BSDs are affected.
      Reported by 'cypherpunks'; fixes bug 11047; bugfix on
    - Avoid strange behavior if two threads hit failed assertions at the
      same time and both try to log backtraces at once. (Previously, if
      this had happened, both threads would have stored their intermediate
      results in the same buffer, and generated junk outputs.) Reported by
      "cypherpunks". Fixes bug 11048; bugfix on
    - Fix a compiler warning in format_number_sigsafe(). Bugfix on; patch from Nick Hopper.

  o Minor bugfixes (unit tests):
    - Fix a small bug in the unit tests that might have made the tests
      call 'chmod' with an uninitialized bitmask. Fixes bug 10928;
      bugfix on Patch from Dana Koch.

  o Removed code:
    - Remove all remaining code related to version-0 hidden service
      descriptors: they have not been in use since Fixes
      the rest of bug 10841.

  o Documentation:
    - 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
    - Fix the manpage's description of HiddenServiceAuthorizeClient:
      the maximum client name length is 16, not 19. Fixes bug 11118;
      bugfix on

  o Code simplifications and refactoring:
    - Get rid of router->address, since in all cases it was just the
      string representation of router->addr. Resolves ticket 5528.

  o Test infrastructure:
    - 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


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