[tor-talk] Tor 0.3.1.3-alpha is released (with security fix for hidden services)

[Nick Mathewson]

Hi!  The latest alpha, 0.3.1.3-alpha, is now released. The source is
available on the website, and packages should be available before too
long.  It has a security fix for hidden services, so if you are
running a hidden service, you should upgrade to this version (or to
one of the 7 other versions released today).

This is an alpha release: if you aren't up for finding and reporting
bugs, you should stick with a stable release series.

As usual, I'll be sending alpha announcements here, and stable
announcements to tor-announce.


Changes in version 0.3.1.3-alpha - 2017-06-08
  Tor 0.3.1.3-alpha fixes a pair of bugs that would allow an attacker to
  remotely crash a hidden service with an assertion failure. Anyone
  running a hidden service should upgrade to this version, or to some
  other version with fixes for TROVE-2017-004 and TROVE-2017-005.

  Tor 0.3.1.3-alpha also includes fixes for several key management bugs
  that sometimes made relays unreliable, as well as several other
  bugfixes described below.

  o Major bugfixes (hidden service, relay, security):
    - Fix a remotely triggerable assertion failure when a hidden service
      handles a malformed BEGIN cell. Fixes bug 22493, tracked as
      TROVE-2017-004 and as CVE-2017-0375; bugfix on 0.3.0.1-alpha.
    - Fix a remotely triggerable assertion failure caused by receiving a
      BEGIN_DIR cell on a hidden service rendezvous circuit. Fixes bug
      22494, tracked as TROVE-2017-005 and CVE-2017-0376; bugfix
      on 0.2.2.1-alpha.

  o Major bugfixes (relay, link handshake):
    - When performing the v3 link handshake on a TLS connection, report
      that we have the x509 certificate that we actually used on that
      connection, even if we have changed certificates since that
      connection was first opened. Previously, we would claim to have
      used our most recent x509 link certificate, which would sometimes
      make the link handshake fail. Fixes one case of bug 22460; bugfix
      on 0.2.3.6-alpha.

  o Major bugfixes (relays, key management):
    - Regenerate link and authentication certificates whenever the key
      that signs them changes; also, regenerate link certificates
      whenever the signed key changes. Previously, these processes were
      only weakly coupled, and we relays could (for minutes to hours)
      wind up with an inconsistent set of keys and certificates, which
      other relays would not accept. Fixes two cases of bug 22460;
      bugfix on 0.3.0.1-alpha.
    - When sending an Ed25519 signing->link certificate in a CERTS cell,
      send the certificate that matches the x509 certificate that we
      used on the TLS connection. Previously, there was a race condition
      if the TLS context rotated after we began the TLS handshake but
      before we sent the CERTS cell. Fixes a case of bug 22460; bugfix
      on 0.3.0.1-alpha.

  o Major bugfixes (torrc, crash):
    - Fix a crash bug when using %include in torrc. Fixes bug 22417;
      bugfix on 0.3.1.1-alpha. Patch by Daniel Pinto.

  o Minor features (code style):
    - Add "Falls through" comments to our codebase, in order to silence
      GCC 7's -Wimplicit-fallthrough warnings. Patch from Andreas
      Stieger. Closes ticket 22446.

  o Minor features (diagnostic):
    - Add logging messages to try to diagnose a rare bug that seems to
      generate RSA->Ed25519 cross-certificates dated in the 1970s. We
      think this is happening because of incorrect system clocks, but
      we'd like to know for certain. Diagnostic for bug 22466.

  o Minor bugfixes (correctness):
    - Avoid undefined behavior when parsing IPv6 entries from the geoip6
      file. Fixes bug 22490; bugfix on 0.2.4.6-alpha.

  o Minor bugfixes (directory protocol):
    - Check for libzstd >= 1.1, because older versions lack the
      necessary streaming API. Fixes bug 22413; bugfix on 0.3.1.1-alpha.

  o Minor bugfixes (link handshake):
    - Lower the lifetime of the RSA->Ed25519 cross-certificate to six
      months, and regenerate it when it is within one month of expiring.
      Previously, we had generated this certificate at startup with a
      ten-year lifetime, but that could lead to weird behavior when Tor
      was started with a grossly inaccurate clock. Mitigates bug 22466;
      mitigation on 0.3.0.1-alpha.

  o Minor bugfixes (storage directories):
    - Always check for underflows in the cached storage directory usage.
      If the usage does underflow, re-calculate it. Also, avoid a
      separate underflow when the usage is not known. Fixes bug 22424;
      bugfix on 0.3.1.1-alpha.

  o Minor bugfixes (unit tests):
    - The unit tests now pass on systems where localhost is misconfigured
      to some IPv4 address other than 127.0.0.1. Fixes bug 6298; bugfix
      on 0.0.9pre2.

  o Documentation:
    - Clarify the manpage for the (deprecated) torify script. Closes
      ticket 6892.