Copy ChangeLog to ReleaseNotes.

ReleaseNotes

@@ -2,6 +2,365 @@ This document summarizes new features and bugfixes in each stable
 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 0.4.0.6 - 2019-12-09
+  This is the second stable release in the 0.4.0.x series. This release
+  backports several bugfixes to improve stability and correctness.  Anyone
+  experiencing build problems or crashes with 0.4.0.5, including all relays
+  relying on AccountingMax, should upgrade.
+
+  Note that, per our support policy, support for the 0.4.0.x series will end
+  on 2 Feb 2020.  Anyone still running 0.4.0.x should plan to upgrade to the
+  latest stable release, or downgrade to 0.3.5.x, which will get long-term
+  support until 1 Feb 2022.
+
+  o Directory authority changes (backport from 0.4.1.5):
+    - The directory authority "dizum" has a new IP address. Closes
+      ticket 31406.
+
+  o Major bugfixes (bridges, backport from 0.4.1.2-alpha):
+    - 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 (circuit build, guard, backport from 0.4.1.4-rc):
+    - When considering upgrading circuits from "waiting for guard" to
+      "open", always ignore circuits that are marked for close. Otherwise,
+      we can end up in the situation where a subsystem is notified that
+      a closing circuit has just opened, leading to undesirable
+      behavior. Fixes bug 30871; bugfix on 0.3.0.1-alpha.
+
+  o Major bugfixes (Onion service reachability, backport from 0.4.1.3-alpha):
+    - Properly clean up the introduction point map when circuits change
+      purpose from onion service circuits to pathbias, measurement, or
+      other circuit types. This should fix some service-side instances
+      of introduction point failure. Fixes bug 29034; bugfix
+      on 0.3.2.1-alpha.
+
+  o Major bugfixes (onion service v3, backport from 0.4.1.1-alpha):
+    - Fix an unreachable bug in which an introduction point could try to
+      send an INTRODUCE_ACK with a status code that Trunnel would refuse
+      to encode, leading the relay to assert(). We've consolidated the
+      ABI values into Trunnel now. Fixes bug 30454; bugfix
+      on 0.3.0.1-alpha.
+    - Clients can now handle unknown status codes from INTRODUCE_ACK
+      cells. (The NACK behavior will stay the same.) This will allow us
+      to extend status codes in the future without breaking the normal
+      client behavior. Fixes another part of bug 30454; bugfix
+      on 0.3.0.1-alpha.
+
+  o Major bugfixes (relay, backport from 0.4.2.3-alpha):
+    - Relays now respect their AccountingMax bandwidth again. When
+      relays entered "soft" hibernation (which typically starts when
+      we've hit 90% of our AccountingMax), we had stopped checking
+      whether we should enter hard hibernation. Soft hibernation refuses
+      new connections and new circuits, but the existing circuits can
+      continue, meaning that relays could have exceeded their configured
+      AccountingMax. Fixes bug 32108; bugfix on 0.4.0.1-alpha.
+
+  o Major bugfixes (torrc parsing, backport from 0.4.2.2-alpha):
+    - Stop ignoring torrc options after an %include directive, when the
+      included directory ends with a file that does not contain any
+      config options (but does contain comments or whitespace). Fixes
+      bug 31408; bugfix on 0.3.1.1-alpha.
+
+  o Major bugfixes (v3 onion services, backport from 0.4.2.3-alpha):
+    - Onion services now always use the exact number of intro points
+      configured with the HiddenServiceNumIntroductionPoints option (or
+      fewer if nodes are excluded). Before, a service could sometimes
+      pick more intro points than configured. Fixes bug 31548; bugfix
+      on 0.3.2.1-alpha.
+
+  o Minor features (compile-time modules, backport from version 0.4.1.1-alpha):
+    - Add a "--list-modules" command to print a list of which compile-
+      time modules are enabled. Closes ticket 30452.
+
+  o Minor features (continuous integration, backport from 0.4.1.1-alpha):
+    - Remove sudo configuration lines from .travis.yml as they are no
+      longer needed with current Travis build environment. Resolves
+      issue 30213.
+
+  o Minor features (continuous integration, backport from 0.4.1.4-rc):
+    - Our Travis configuration now uses Chutney to run some network
+      integration tests automatically. Closes ticket 29280.
+
+  o Minor features (continuous integration, backport from 0.4.2.2-alpha):
+    - When building on Appveyor and Travis, pass the "-k" flag to make,
+      so that we are informed of all compilation failures, not just the
+      first one or two. Closes ticket 31372.
+
+  o Minor features (fallback directory list, backport from 0.4.1.4-rc):
+    - Replace the 157 fallbacks originally introduced in Tor 0.3.5.6-rc
+      in December 2018 (of which ~122 were still functional), with a
+      list of 148 fallbacks (70 new, 78 existing, 79 removed) generated
+      in June 2019. Closes ticket 28795.
+
+  o Minor features (geoip, backport from 0.4.2.5):
+    - Update geoip and geoip6 to the December 3 2019 Maxmind GeoLite2
+      Country database. Closes ticket 32685.
+
+  o Minor features (stem tests, backport from 0.4.2.1-alpha):
+    - Change "make test-stem" so it only runs the stem tests that use
+      tor. This change makes test-stem faster and more reliable. Closes
+      ticket 31554.
+
+  o Minor bugfixes (Appveyor CI, backport from 0.4.2.2-alpha):
+    - Avoid spurious errors when Appveyor CI fails before the install step.
+      Fixes bug 31884; bugfix on 0.3.4.2-alpha.
+
+  o Minor bugfixes (build system, backport form 0.4.2.1-alpha):
+    - Do not include the deprecated <sys/sysctl.h> on Linux or Windows
+      systems. Fixes bug 31673; bugfix on 0.2.5.4-alpha.
+
+  o Minor bugfixes (circuit isolation, backport from 0.4.1.3-alpha):
+    - Fix a logic error that prevented the SessionGroup sub-option from
+      being accepted. Fixes bug 22619; bugfix on 0.2.7.2-alpha.
+
+  o Minor bugfixes (circuit padding, backport from 0.4.1.4-rc):
+    - On relays, properly check that a padding machine is absent before
+      logging a warning about it being absent. Fixes bug 30649; bugfix
+      on 0.4.0.1-alpha.
+
+  o Minor bugfixes (client, onion service v3, backport from 0.4.2.4-rc):
+    - Fix a BUG() assertion that occurs within a very small race window
+      between when a client intro circuit opens and when its descriptor
+      gets cleaned up from the cache. The circuit is now closed early,
+      which will trigger a re-fetch of the descriptor and continue the
+      connection. Fixes bug 28970; bugfix on 0.3.2.1-alpha.
+
+  o Minor bugfixes (clock skew detection, backport from 0.4.1.5):
+    - Don't believe clock skew results from NETINFO cells that appear to
+      arrive before we sent the VERSIONS cells they are responding to.
+      Previously, we would accept them up to 3 minutes "in the past".
+      Fixes bug 31343; bugfix on 0.2.4.4-alpha.
+
+  o Minor bugfixes (compilation warning, backport from 0.4.1.5):
+    - Fix a compilation warning on Windows about casting a function
+      pointer for GetTickCount64(). Fixes bug 31374; bugfix
+      on 0.2.9.1-alpha.
+
+  o Minor bugfixes (compilation, backport from 0.4.1.5):
+    - Avoid using labs() on time_t, which can cause compilation warnings
+      on 64-bit Windows builds. Fixes bug 31343; bugfix on 0.2.4.4-alpha.
+
+  o Minor bugfixes (compilation, backport from 0.4.2.1-alpha):
+    - Suppress spurious float-conversion warnings from GCC when calling
+      floating-point classifier functions on FreeBSD. Fixes part of bug
+      31687; bugfix on 0.3.1.5-alpha.
+
+  o Minor bugfixes (compilation, unusual configurations, backport from 0.4.1.1-alpha):
+    - Avoid failures when building with the ALL_BUGS_ARE_FATAL option
+      due to missing declarations of abort(), and prevent other such
+      failures in the future. Fixes bug 30189; bugfix on 0.3.4.1-alpha.
+
+  o Minor bugfixes (configuration, proxies, backport from 0.4.1.2-alpha):
+    - 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 (connections, backport from 0.4.2.3-rc):
+    - Avoid trying to read data from closed connections, which can cause
+      needless loops in Libevent and infinite loops in Shadow. Fixes bug
+      30344; bugfix on 0.1.1.1-alpha.
+
+  o Minor bugfixes (continuous integration, backport from 0.4.1.3-alpha):
+    - Allow the test-stem job to fail in Travis, because it sometimes
+      hangs. Fixes bug 30744; bugfix on 0.3.5.4-alpha.
+    - Skip test_rebind on macOS in Travis, because it is unreliable on
+      macOS on Travis. Fixes bug 30713; bugfix on 0.3.5.1-alpha.
+    - Skip test_rebind when the TOR_SKIP_TEST_REBIND environment
+      variable is set. Fixes bug 30713; bugfix on 0.3.5.1-alpha.
+
+  o Minor bugfixes (crash on exit, backport from 0.4.1.4-rc):
+    - Avoid a set of possible code paths that could try to use freed
+      memory in routerlist_free() while Tor was exiting. Fixes bug
+      31003; bugfix on 0.1.2.2-alpha.
+
+  o Minor bugfixes (directory authorities, backport from 0.4.1.3-alpha):
+    - Stop crashing after parsing an unknown descriptor purpose
+      annotation. We think this bug can only be triggered by modifying a
+      local file. Fixes bug 30781; bugfix on 0.2.0.8-alpha.
+
+  o Minor bugfixes (directory authority, backport from 0.4.1.2-alpha):
+    - 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 (error handling, backport from 0.4.2.1-alpha):
+    - On abort, try harder to flush the output buffers of log messages.
+      On some platforms (macOS), log messages could be discarded when
+      the process terminates. Fixes bug 31571; bugfix on 0.3.5.1-alpha.
+    - Report the tor version whenever an assertion fails. Previously, we
+      only reported the Tor version on some crashes, and some non-fatal
+      assertions. Fixes bug 31571; bugfix on 0.3.5.1-alpha.
+
+  o Minor bugfixes (FreeBSD, PF-based proxy, IPv6, backport from 0.4.2.1-alpha):
+    - When extracting an IPv6 address from a PF-based proxy, verify that
+      we are actually configured to receive an IPv6 address, and log an
+      internal error if not. Fixes part of bug 31687; bugfix
+      on 0.2.3.4-alpha.
+
+  o Minor bugfixes (guards, backport from 0.4.2.1-alpha):
+    - When tor is missing descriptors for some primary entry guards,
+      make the log message less alarming. It's normal for descriptors to
+      expire, as long as tor fetches new ones soon after. Fixes bug
+      31657; bugfix on 0.3.3.1-alpha.
+
+  o Minor bugfixes (logging, backport from 0.4.1.1-alpha):
+    - Do not log a warning when running with an OpenSSL version other
+      than the one Tor was compiled with, if the two versions should be
+      compatible. Previously, we would warn whenever the version was
+      different. Fixes bug 30190; bugfix on 0.2.4.2-alpha.
+
+  o Minor bugfixes (logging, backport from 0.4.2.1-alpha):
+    - Change log level of message "Hash of session info was not as
+      expected" to LOG_PROTOCOL_WARN. Fixes bug 12399; bugfix
+      on 0.1.1.10-alpha.
+
+  o Minor bugfixes (logging, backport from 0.4.2.2-alpha):
+    - Rate-limit our the logging message about the obsolete .exit
+      notation. Previously, there was no limit on this warning, which
+      could potentially be triggered many times by a hostile website.
+      Fixes bug 31466; bugfix on 0.2.2.1-alpha.
+
+  o Minor bugfixes (logging, protocol violations, backport from 0.4.2.2-alpha):
+    - Do not log a nonfatal assertion failure when receiving a VERSIONS
+      cell on a connection using the obsolete v1 link protocol. Log a
+      protocol_warn instead. Fixes bug 31107; bugfix on 0.2.4.4-alpha.
+
+  o Minor bugfixes (mainloop, periodic events, in-process API, backport from 0.4.2.3-alpha):
+    - Reset the periodic events' "enabled" flag when Tor is shut down
+      cleanly. Previously, this flag was left on, which caused periodic
+      events not to be re-enabled when Tor was relaunched in-process
+      with tor_api.h after a shutdown. Fixes bug 32058; bugfix
+      on 0.3.3.1-alpha.
+
+  o Minor bugfixes (memory leak, backport from 0.4.1.1-alpha):
+    - Avoid a minor memory leak that could occur on relays when failing
+      to create a "keys" directory. Fixes bug 30148; bugfix
+      on 0.3.3.1-alpha.
+
+  o Minor bugfixes (memory leak, backport from 0.4.1.4-rc):
+    - Fix a trivial memory leak when parsing an invalid value
+      from a download schedule in the configuration. Fixes bug
+      30894; bugfix on 0.3.4.1-alpha.
+
+  o Minor bugfixes (NetBSD, backport from 0.4.1.2-alpha):
+    - 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 (onion services, backport from 0.4.1.1-alpha):
+    - Avoid a GCC 9.1.1 warning (and possible crash depending on libc
+      implemenation) when failing to load an onion service client
+      authorization file. Fixes bug 30475; bugfix on 0.3.5.1-alpha.
+
+  o Minor bugfixes (out-of-memory handler, backport from 0.4.1.2-alpha):
+    - 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, backport from 0.4.1.2-alpha):
+    - 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 (process management, backport from 0.4.2.3-alpha):
+    - Remove overly strict assertions that triggered when a pluggable
+      transport failed to launch. Fixes bug 31091; bugfix
+      on 0.4.0.1-alpha.
+    - Remove an assertion in the Unix process backend. This assertion
+      would trigger when we failed to find the executable for a child
+      process. Fixes bug 31810; bugfix on 0.4.0.1-alpha.
+
+  o Minor bugfixes (relay, backport from 0.4.2.2-alpha):
+    - Avoid crashing when starting with a corrupt keys directory where
+      the old ntor key and the new ntor key are identical. Fixes bug
+      30916; bugfix on 0.2.4.8-alpha.
+
+  o Minor bugfixes (rust, backport from 0.4.2.1-alpha):
+    - Correctly exclude a redundant rust build job in Travis. Fixes bug
+      31463; bugfix on 0.3.5.4-alpha.
+
+  o Minor bugfixes (testing, backport from 0.4.2.3-alpha):
+    - When testing port rebinding, don't busy-wait for tor to log.
+      Instead, actually sleep for a short time before polling again.
+      Also improve the formatting of control commands and log messages.
+      Fixes bug 31837; bugfix on 0.3.5.1-alpha.
+
+  o Minor bugfixes (tls, logging, backport from 0.4.2.3-alpha):
+    - Log bugs about the TLS read buffer's length only once, rather than
+      filling the logs with similar warnings. Fixes bug 31939; bugfix
+      on 0.3.0.4-rc.
+
+  o Minor bugfixes (v2 single onion services, backport from 0.4.2.1-alpha):
+    - Always retry v2 single onion service intro and rend circuits with
+      a 3-hop path. Previously, v2 single onion services used a 3-hop
+      path when rendezvous circuits were retried after a remote or
+      delayed failure, but a 1-hop path for immediate retries. Fixes bug
+      23818; bugfix on 0.2.9.3-alpha.
+    - Make v3 single onion services fall back to a 3-hop intro, when all
+      intro points are unreachable via a 1-hop path. Previously, v3
+      single onion services failed when all intro nodes were unreachable
+      via a 1-hop path. Fixes bug 23507; bugfix on 0.3.2.1-alpha.
+
+  o Documentation (backport from 0.4.2.1-alpha):
+    - Use RFC 2397 data URL scheme to embed an image into tor-exit-
+      notice.html so that operators no longer have to host it
+      themselves. Closes ticket 31089.
+
+  o Testing (backport from 0.4.1.2-alpha):
+    - Specify torrc paths (with empty files) when launching tor in
+      integration tests; refrain from reading user and system torrcs.
+      Resolves issue 29702.
+
+  o Testing (continuous integration, backport from 0.4.1.1-alpha):
+    - In Travis, show stem's tor log after failure. Closes ticket 30234.
+
+  o Testing (continuous integration, backport from 0.4.1.5):
+    - In Travis, make stem log a controller trace to the console, and
+      tail stem's tor log after failure. Closes ticket 30591.
+    - In Travis, only run the stem tests that use a tor binary. Closes
+      ticket 30694.
+
+  o Testing (continuous integration, backport from 0.4.2.3-alpha):
+    - Disable all but one Travis CI macOS build, to mitigate slow
+      scheduling of Travis macOS jobs. Closes ticket 32177.
+    - Run the chutney IPv6 networks as part of Travis CI. Closes
+      ticket 30860.
+    - Simplify the Travis CI build matrix, and optimise for build time.
+      Closes ticket 31859.
+    - Use Windows Server 2019 instead of Windows Server 2016 in our
+      Appveyor builds. Closes ticket 32086.
+
+  o Testing (continuous integration, backport from 0.4.2.4-rc):
+    - Use Ubuntu Bionic images for our Travis CI builds, so we can get a
+      recent version of coccinelle. But leave chutney on Ubuntu Trusty,
+      until we can fix some Bionic permissions issues (see ticket
+      32240). Related to ticket 31919.
+    - Install the mingw OpenSSL package in Appveyor. This makes sure
+      that the OpenSSL headers and libraries match in Tor's Appveyor
+      builds. (This bug was triggered by an Appveyor image update.)
+      Fixes bug 32449; bugfix on 0.3.5.6-rc.
+    - In Travis, use Xcode 11.2 on macOS 10.14. Closes ticket 32241.
+
+  o Testing (continuous integration, backport from 0.4.2.5):
+    - Require C99 standards-conforming code in Travis CI, but allow GNU gcc
+      extensions. Also activates clang's -Wtypedef-redefinition warnings.
+      Build some jobs with -std=gnu99, and some jobs without.
+      Closes ticket 32500.
+
+
 Changes in version 0.4.0.5 - 2019-05-02
   This is the first stable release in the 0.4.0.x series. It contains
   improvements for power management and bootstrap reporting, as well as