Copy ChangeLog into ReleaseNotes.

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 0.3.5.15 - 2021-06-14

  Tor 0.3.5.15 fixes several security issues, including a

  denial-of-service attack against onion service clients, and another

  denial-of-service attack against relays. Everybody should upgrade to

  one of 0.3.5.15, 0.4.4.9, 0.4.5.9, or 0.4.6.5.

  o Major bugfixes (security, backport from 0.4.6.5):

    - Don't allow relays to spoof RELAY_END or RELAY_RESOLVED cell on

      half-closed streams. Previously, clients failed to validate which

      hop sent these cells: this would allow a relay on a circuit to end

      a stream that wasn't actually built with it. Fixes bug 40389;

      bugfix on 0.3.5.1-alpha. This issue is also tracked as TROVE-2021-

      003 and CVE-2021-34548.

  o Major bugfixes (security, defense-in-depth, backport from 0.4.6.5):

    - Detect more failure conditions from the OpenSSL RNG code.

      Previously, we would detect errors from a missing RNG

      implementation, but not failures from the RNG code itself.

      Fortunately, it appears those failures do not happen in practice

      when Tor is using OpenSSL's default RNG implementation. Fixes bug

      40390; bugfix on 0.2.8.1-alpha. This issue is also tracked as

      TROVE-2021-004. Reported by Jann Horn at Google's Project Zero.

  o Major bugfixes (security, denial of service, backport from 0.4.6.5):

    - Resist a hashtable-based CPU denial-of-service attack against

      relays. Previously we used a naive unkeyed hash function to look

      up circuits in a circuitmux object. An attacker could exploit this

      to construct circuits with chosen circuit IDs, to create

      collisions and make the hash table inefficient. Now we use a

      SipHash construction here instead. Fixes bug 40391; bugfix on

      0.2.4.4-alpha. This issue is also tracked as TROVE-2021-005 and

      CVE-2021-34549. Reported by Jann Horn from Google's Project Zero.

    - Fix an out-of-bounds memory access in v3 onion service descriptor

      parsing. An attacker could exploit this bug by crafting an onion

      service descriptor that would crash any client that tried to visit

      it. Fixes bug 40392; bugfix on 0.3.0.1-alpha. This issue is also

      tracked as TROVE-2021-006 and CVE-2021-34550. Reported by Sergei

      Glazunov from Google's Project Zero.

  o Minor bugfixes (compiler warnings, backport from 0.4.6.3-rc):

    - Fix an indentation problem that led to a warning from GCC 11.1.1.

      Fixes bug 40380; bugfix on 0.3.0.1-alpha.

  o Minor features (compatibility, backport from 0.4.6.4-rc):

    - Remove an assertion function related to TLS renegotiation. It was

      used nowhere outside the unit tests, and it was breaking

      compilation with recent alpha releases of OpenSSL 3.0.0. Closes

      ticket 40399.

  o Minor features (fallback directory list, backport from 0.4.6.2-alpha):

    - Regenerate the list of fallback directories to contain a new set

      of 200 relays. Closes ticket 40265.

  o Minor features (geoip data):

    - Update the geoip files to match the IPFire Location Database, as

      retrieved on 2021/06/10.

Changes in version 0.3.5.14 - 2021-03-16

  Tor 0.3.5.14 backports fixes for two important denial-of-service bugs

  in earlier versions of Tor.