Newer
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Changes in version 0.4.7.1-alpha - 2021-09-17
This version is the first alpha release of the 0.4.7.x series. One
major feature is Vanguards Lite, from proposal 333, to help mitigate
guard discovery attacks against onion services. It also includes
numerous bugfixes.
o Major features (Proposal 332, onion services, guard selection algorithm):
- Clients and onion services now choose four long-lived "layer 2"
guard relays for use as the middle hop in all onion circuits.
These relays are kept in place for a randomized duration averaging
1 week. This mitigates guard discovery attacks against clients and
short-lived onion services such as OnionShare. Long-lived onion
services that need high security should still use the Vanguards
addon (https://github.com/mikeperry-tor/vanguards). Closes ticket
40363; implements proposal 333.
o Minor features (bridge testing support):
- Let external bridge reachability testing tools discard cached
bridge descriptors when setting new bridges, so they can be sure
to get a clean reachability test. Implements ticket 40209.
o Minor features (fuzzing):
- When building with --enable-libfuzzer, use a set of compiler flags
that works with more recent versions of the library. Previously we
were using a set of flags from 2017. Closes ticket 40407.
o Minor features (testing configuration):
- When TestingTorNetwork is enabled, skip the permissions check on
hidden service directories. Closes ticket 40338.
- On a testing network, relays can now use the
TestingMinTimeToReportBandwidth option to change the smallest
amount of time over which they're willing to report their observed
maximum bandwidth. Previously, this was fixed at 1 day. For
safety, values under 2 hours are only supported on testing
networks. Part of a fix for ticket 40337.
- Relays on testing networks no longer rate-limit how frequently
they are willing to report new bandwidth measurements. Part of a
fix for ticket 40337.
- Relays on testing networks now report their observed bandwidths
immediately from startup. Previously, they waited until they had
been running for a full day. Closes ticket 40337.
o Minor bugfixes (circuit padding):
- Don't send STOP circuit padding cells when the other side has
already shut down the corresponding padding machine. Fixes bug
40435; bugfix on 0.4.0.1-alpha.
o Minor bugfixes (compatibility):
- Fix compatibility with the most recent Libevent versions, which no
longer have an evdns_set_random_bytes() function. Because this
function has been a no-op since Libevent 2.0.4-alpha, it is safe
for us to just stop calling it. Fixes bug 40371; bugfix
on 0.2.1.7-alpha.
o Minor bugfixes (control, sandbox):
- Allows the control command SAVECONF to succeed when the seccomp
sandbox is enabled. Makes SAVECONF keep only one backup file, to
simplify implementation. Fixes bug 40317; bugfix on 0.2.5.4-alpha.
Patch by Daniel Pinto.
o Minor bugfixes (heartbeat):
- Adjust the heartbeat log message about distinct clients to
consider the HeartbeatPeriod rather than a flat 6-hour delay.
Fixes bug 40330; bugfix on 0.2.6.3-alpha.
o Minor bugfixes (logging, relay):
- Add spaces between the "and" when logging the "Your server has not
managed to confirm reachability for its" on dual-stack relays.
Fixes bug 40453; bugfix on 0.4.5.1-alpha. Patch by Neel Chauhan.
o Minor bugfixes (onion service):
- Do not flag an HSDir as non-running in case the descriptor upload
or fetch fails. An onion service closes pending directory
connections before uploading a new descriptor which leads to
wrongly flagging many relays and thus affecting circuit path
selection. Fixes bug 40434; bugfix on 0.2.0.13-alpha.
o Minor bugfixes (statistics):
- Fix a fencepost issue when we check stability_last_downrated where
we called rep_hist_downrate_old_runs() twice. Fixes bug 40394;
bugfix on 0.2.0.5-alpha. Patch by Neel Chauhan.
o Minor bugfixes (tests):
- Fix a bug that prevented some tests from running with the correct
names. Fixes bug 40365; bugfix on 0.4.3.1-alpha.
o Documentation:
- Add links to original tor design paper and anonbib to
docs/HACKING/README.1st.md. Closes ticket 33742. Patch from
Emily Bones.
- Describe the "fingerprint-ed25519" file in the tor.1 man page.
Fixes bug 40467; bugfix on 0.4.3.1-alpha. Patch by Neel Chauhan.
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Changes in version 0.4.6.7 - 2021-08-16
This version fixes several bugs from earlier versions of Tor,
including one that could lead to a denial-of-service attack. Everyone
running an earlier version, whether as a client, a relay, or an onion
service, should upgrade to Tor 0.3.5.16, 0.4.5.10, or 0.4.6.7.
o Major bugfixes (cryptography, security):
- Resolve an assertion failure caused by a behavior mismatch between
our batch-signature verification code and our single-signature
verification code. This assertion failure could be triggered
remotely, leading to a denial of service attack. We fix this issue
by disabling batch verification. Fixes bug 40078; bugfix on
0.2.6.1-alpha. This issue is also tracked as TROVE-2021-007 and
CVE-2021-38385. Found by Henry de Valence.
o Minor feature (fallbackdir):
- Regenerate fallback directories list. Close ticket 40447.
o Minor features (geoip data):
- Update the geoip files to match the IPFire Location Database, as
retrieved on 2021/08/12.
o Minor bugfix (crypto):
- Disable the unused batch verification feature of ed25519-donna.
Fixes bug 40078; bugfix on 0.2.6.1-alpha. Found by Henry
de Valence.
o Minor bugfixes (onion service):
- Send back the extended SOCKS error 0xF6 (Onion Service Invalid
Address) for a v2 onion address. Fixes bug 40421; bugfix
on 0.4.6.2-alpha.
o Minor bugfixes (relay):
- Reduce the compression level for data streaming from HIGH to LOW
in order to reduce CPU load on the directory relays. Fixes bug
40301; bugfix on 0.3.5.1-alpha.
o Minor bugfixes (timekeeping):
- Calculate the time of day correctly on systems where the time_t
type includes leap seconds. (This is not the case on most
operating systems, but on those where it occurs, our tor_timegm
function did not correctly invert the system's gmtime function,
which could result in assertion failures when calculating voting
schedules.) Fixes bug 40383; bugfix on 0.2.0.3-alpha.
Changes in version 0.4.5.10 - 2021-08-16
This version fixes several bugs from earlier versions of Tor,
including one that could lead to a denial-of-service attack. Everyone
running an earlier version, whether as a client, a relay, or an onion
service, should upgrade to Tor 0.3.5.16, 0.4.5.10, or 0.4.6.7.
o Major bugfixes (cryptography, security):
- Resolve an assertion failure caused by a behavior mismatch between
our batch-signature verification code and our single-signature
verification code. This assertion failure could be triggered
remotely, leading to a denial of service attack. We fix this issue
by disabling batch verification. Fixes bug 40078; bugfix on
0.2.6.1-alpha. This issue is also tracked as TROVE-2021-007 and
CVE-2021-38385. Found by Henry de Valence.
o Minor feature (fallbackdir):
- Regenerate fallback directories list. Close ticket 40447.
o Minor features (geoip data):
- Update the geoip files to match the IPFire Location Database, as
retrieved on 2021/08/12.
o Minor features (testing):
- Enable the deterministic RNG for unit tests that covers the
address set bloomfilter-based API's. Fixes bug 40419; bugfix
on 0.3.3.2-alpha.
o Minor bugfix (crypto, backport from 0.4.6.7):
- Disable the unused batch verification feature of ed25519-donna.
Fixes bug 40078; bugfix on 0.2.6.1-alpha. Found by Henry
de Valence.
o Minor bugfixes (relay, backport from 0.4.6.7):
- Reduce the compression level for data streaming from HIGH to LOW.
Fixes bug 40301; bugfix on 0.3.5.1-alpha.
o Minor bugfixes (timekeeping, backport from 0.4.6.7):
- Calculate the time of day correctly on systems where the time_t
type includes leap seconds. (This is not the case on most
operating systems, but on those where it occurs, our tor_timegm
function did not correctly invert the system's gmtime function,
which could result in assertion failures when calculating voting
schedules.) Fixes bug 40383; bugfix on 0.2.0.3-alpha.
o Minor bugfixes (warnings, portability, backport from 0.4.6.6):
- Suppress a strict-prototype warning when building with some
versions of NSS. Fixes bug 40409; bugfix on 0.3.5.1-alpha.
Changes in version 0.3.5.16 - 2021-08-16
This version fixes several bugs from earlier versions of Tor,
including one that could lead to a denial-of-service attack. Everyone
running an earlier version, whether as a client, a relay, or an onion
service, should upgrade to Tor 0.3.5.16, 0.4.5.10, or 0.4.6.7.
o Major bugfixes (cryptography, security):
- Resolve an assertion failure caused by a behavior mismatch between
our batch-signature verification code and our single-signature
verification code. This assertion failure could be triggered
remotely, leading to a denial of service attack. We fix this issue
by disabling batch verification. Fixes bug 40078; bugfix on
0.2.6.1-alpha. This issue is also tracked as TROVE-2021-007 and
CVE-2021-38385. Found by Henry de Valence.
o Minor feature (fallbackdir):
- Regenerate fallback directories list. Close ticket 40447.
o Minor features (geoip data):
- Update the geoip files to match the IPFire Location Database, as
retrieved on 2021/08/12.
o Minor bugfix (crypto, backport from 0.4.6.7):
- Disable the unused batch verification feature of ed25519-donna.
Fixes bug 40078; bugfix on 0.2.6.1-alpha. Found by Henry
de Valence.
o Minor bugfixes (relay, backport from 0.4.6.7):
- Reduce the compression level for data streaming from HIGH to LOW.
Fixes bug 40301; bugfix on 0.3.5.1-alpha.
Changes in version 0.4.6.6 - 2021-06-30
Tor 0.4.6.6 makes several small fixes on 0.4.6.5, including one that
allows Tor to build correctly on older versions of GCC. You should
upgrade to this version if you were having trouble building Tor
0.4.6.5; otherwise, there is probably no need.
o Minor bugfixes (compilation):
- Fix a compilation error when trying to build Tor with a compiler
that does not support const variables in static initializers.
Fixes bug 40410; bugfix on 0.4.6.5.
- Suppress a strict-prototype warning when building with some
versions of NSS. Fixes bug 40409; bugfix on 0.3.5.1-alpha.
o Minor bugfixes (testing):
- Enable the deterministic RNG for unit tests that covers the
address set bloomfilter-based API's. Fixes bug 40419; bugfix
on 0.3.3.2-alpha.

Nick Mathewson
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Changes in version 0.4.5.9 - 2021-06-14
Tor 0.4.5.9 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 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 (geoip data):
- Update the geoip files to match the IPFire Location Database, as
retrieved on 2021/06/10.
o Minor bugfixes (control, sandbox, backport from 0.4.6.4-rc):
- Allow the control command SAVECONF to succeed when the seccomp
sandbox is enabled, and make SAVECONF keep only one backup file to
simplify implementation. Previously SAVECONF allowed a large
number of backup files, which made it incompatible with the
sandbox. Fixes bug 40317; bugfix on 0.2.5.4-alpha. Patch by
Daniel Pinto.
o Minor bugfixes (metrics port, backport from 0.4.6.4-rc):
- Fix a bug that made tor try to re-bind() on an already open
MetricsPort every 60 seconds. Fixes bug 40370; bugfix
on 0.4.5.1-alpha.
Changes in version 0.4.4.9 - 2021-06-14
Tor 0.4.4.9 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.
Note that the scheduled end-of-life date for the Tor 0.4.4.x series is
June 15. This is therefore the last release in its series. Everybody
still running 0.4.4.x should plan to upgrade to 0.4.5.x or later.
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 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.
o Minor bugfixes (channel, DoS, backport from 0.4.6.2-alpha):
- Fix a non-fatal BUG() message due to a too-early free of a string,
when listing a client connection from the DoS defenses subsystem.
Fixes bug 40345; bugfix on 0.4.3.4-rc.
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.
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.
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Changes in version 0.4.6.5 - 2021-06-14
Tor 0.4.6.5 is the first stable release in its series. The 0.4.6.x
series includes numerous features and bugfixes, including a significant
improvement to our circuit timeout algorithm that should improve
observed client performance, and a way for relays to report when they are
overloaded.
This release also includes security fixes for 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.
Below are the changes since 0.4.6.4-rc. For a complete list of changes
since 0.4.5.8, see the ReleaseNotes file.
o Major bugfixes (security):
- 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):
- 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):
- 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 features (geoip data):
- Update the geoip files to match the IPFire Location Database, as
retrieved on 2021/06/10.
o Minor features (logging, diagnostic):
- Log decompression failures at a higher severity level, since they
can help provide missing context for other warning messages. We
rate-limit these messages, to avoid flooding the logs if they
begin to occur frequently. Closes ticket 40175.
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Changes in version 0.4.6.4-rc - 2021-05-28
Tor 0.4.6.4-rc fixes a few bugs from previous releases. This, we hope,
the final release candidate in its series: unless major new issues are
found, the next release will be stable.
o Minor features (compatibility):
- 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 bugfixes (consensus handling):
- Avoid a set of bugs that could be caused by inconsistently
preferring an out-of-date consensus stored in a stale directory
cache over a more recent one stored on disk as the latest
consensus. Fixes bug 40375; bugfix on 0.3.1.1-alpha.
o Minor bugfixes (control, sandbox):
- Allow the control command SAVECONF to succeed when the seccomp
sandbox is enabled, and make SAVECONF keep only one backup file to
simplify implementation. Previously SAVECONF allowed a large
number of backup files, which made it incompatible with the
sandbox. Fixes bug 40317; bugfix on 0.2.5.4-alpha. Patch by
Daniel Pinto.
o Minor bugfixes (metrics port):
- Fix a bug that made tor try to re-bind() on an already open
MetricsPort every 60 seconds. Fixes bug 40370; bugfix
on 0.4.5.1-alpha.
o Removed features:
- Remove unneeded code for parsing private keys in directory
documents. This code was only used for client authentication in v2
onion services, which are now unsupported. Closes ticket 40374.
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Changes in version 0.4.5.8 - 2021-05-10
Tor 0.4.5.8 fixes several bugs in earlier version, backporting fixes
from the 0.4.6.x series.
o Minor features (compatibility, Linux seccomp sandbox, backport from 0.4.6.3-rc):
- Add a workaround to enable the Linux sandbox to work correctly
with Glibc 2.33. This version of Glibc has started using the
fstatat() system call, which previously our sandbox did not allow.
Closes ticket 40382; see the ticket for a discussion of trade-offs.
o Minor features (compilation, backport from 0.4.6.3-rc):
- Make the autoconf script build correctly with autoconf versions
2.70 and later. Closes part of ticket 40335.
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 2021/05/07.
o Minor features (onion services):
- Add warning message when connecting to now deprecated v2 onion
services. As announced, Tor 0.4.5.x is the last series that will
support v2 onions. Closes ticket 40373.
o Minor bugfixes (bridge, pluggable transport, backport from 0.4.6.2-alpha):
- Fix a regression that made it impossible start Tor using a bridge
line with a transport name and no fingerprint. Fixes bug 40360;
bugfix on 0.4.5.4-rc.
o Minor bugfixes (build, cross-compilation, backport from 0.4.6.3-rc):
- Allow a custom "ar" for cross-compilation. Our previous build
script had used the $AR environment variable in most places, but
it missed one. Fixes bug 40369; bugfix on 0.4.5.1-alpha.
o Minor bugfixes (channel, DoS, backport from 0.4.6.2-alpha):
- Fix a non-fatal BUG() message due to a too-early free of a string,
when listing a client connection from the DoS defenses subsystem.
Fixes bug 40345; bugfix on 0.4.3.4-rc.
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 bugfixes (controller, backport from 0.4.6.1-alpha):
- Fix a "BUG" warning that would appear when a controller chooses
the first hop for a circuit, and that circuit completes. Fixes bug
40285; bugfix on 0.3.2.1-alpha.
o Minor bugfixes (onion service, client, memory leak, backport from 0.4.6.3-rc):
- Fix a bug where an expired cached descriptor could get overwritten
with a new one without freeing it, leading to a memory leak. Fixes
bug 40356; bugfix on 0.3.5.1-alpha.
o Minor bugfixes (testing, BSD, backport from 0.4.6.2-alpha):
- Fix pattern-matching errors when patterns expand to invalid paths
on BSD systems. Fixes bug 40318; bugfix on 0.4.5.1-alpha. Patch by
Daniel Pinto.
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Changes in version 0.4.6.3-rc - 2021-05-10
Tor 0.4.6.3-rc is the first release candidate in its series. It fixes
a few small bugs from previous versions, and adds a better error
message when trying to use (no longer supported) v2 onion services.
Though we anticipate that we'll be doing a bit more clean-up between
now and the stable release, we expect that our remaining changes will
be fairly simple. There will likely be at least one more release
candidate before 0.4.6.x is stable.
o Major bugfixes (onion service, control port):
- Make the ADD_ONION command properly configure client authorization.
Before this fix, the created onion failed to add the client(s).
Fixes bug 40378; bugfix on 0.4.6.1-alpha.
o Minor features (compatibility, Linux seccomp sandbox):
- Add a workaround to enable the Linux sandbox to work correctly
with Glibc 2.33. This version of Glibc has started using the
fstatat() system call, which previously our sandbox did not allow.
Closes ticket 40382; see the ticket for a discussion of trade-offs.
o Minor features (compilation):
- Make the autoconf script build correctly with autoconf versions
2.70 and later. Closes part of ticket 40335.
o Minor features (geoip data):
- Update the geoip files to match the IPFire Location Database, as
retrieved on 2021/05/07.
o Minor features (onion services):
- Add a warning message when trying to connect to (no longer
supported) v2 onion services. Closes ticket 40373.
o Minor bugfixes (build, cross-compilation):
- Allow a custom "ar" for cross-compilation. Our previous build
script had used the $AR environment variable in most places, but
it missed one. Fixes bug 40369; bugfix on 0.4.5.1-alpha.
o Minor bugfixes (compiler warnings):
- 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 bugfixes (logging, relay):
- Emit a warning if an Address is found to be internal and tor can't
use it. Fixes bug 40290; bugfix on 0.4.5.1-alpha.
o Minor bugfixes (onion service, client, memory leak):
- Fix a bug where an expired cached descriptor could get overwritten
with a new one without freeing it, leading to a memory leak. Fixes
bug 40356; bugfix on 0.3.5.1-alpha.
Changes in version 0.4.6.2-alpha - 2021-04-15
Tor 0.4.6.2-alpha is the second alpha in its series. It fixes several
small bugs in previous releases, and solves other issues that had
enabled denial-of-service attacks and affected integration with
other tools.
o Minor features (client):
- Clients now check whether their streams are attempting to re-enter
the Tor network (i.e. to send Tor traffic over Tor), and close
them preemptively if they think exit relays will refuse them for
this reason. See ticket 2667 for details. Closes ticket 40271.
o Minor features (command line):
- Add long format name "--torrc-file" equivalent to the existing
command-line option "-f". Closes ticket 40324. Patch by
Daniel Pinto.
o Minor features (dormant mode):
- Add a new 'DormantTimeoutEnabled' option to allow coarse-grained
control over whether the client ever becomes dormant from
inactivity. Most people won't need this. Closes ticket 40228.
- Regenerate the list of fallback directories to contain a new set
o Minor features (geoip data):
- Update the geoip files to match the IPFire Location Database, as
retrieved on 2021/04/13.
o Minor features (logging):
- Edit heartbeat log messages so that more of them begin with the
string "Heartbeat: ". Closes ticket 40322; patch
from 'cypherpunks'.
o Minor bugfixes (bridge, pluggable transport):
- Fix a regression that made it impossible start Tor using a bridge
line with a transport name and no fingerprint. Fixes bug 40360;
bugfix on 0.4.5.4-rc.
o Minor bugfixes (channel, DoS):
- Fix a non-fatal BUG() message due to a too-early free of a string,
when listing a client connection from the DoS defenses subsystem.
o Minor bugfixes (compilation):
- Fix a compilation warning about unused functions when building
with a libc that lacks the GLOB_ALTDIRFUNC constant. Fixes bug
40354; bugfix on 0.4.5.1-alpha. Patch by Daniel Pinto.
o Minor bugfixes (configuration):
- Fix pattern-matching for directories on all platforms when using
%include options in configuration files. This patch also fixes
compilation on musl libc based systems. Fixes bug 40141; bugfix
on 0.4.5.1-alpha.
o Minor bugfixes (relay):
- Move the "overload-general" line from extrainfo to the server
descriptor. Fixes bug 40364; bugfix on 0.4.6.1-alpha.
o Minor bugfixes (testing, BSD):
- Fix pattern-matching errors when patterns expand to invalid paths
on BSD systems. Fixes bug 40318; bugfix on 0.4.5.1-alpha. Patch by
Daniel Pinto.
o Documentation (manual):
- Move the ServerTransport* options to the "SERVER OPTIONS" section.
- Indicate that the HiddenServiceStatistics option also applies to
bridges. Closes ticket 40346.
- Move the description of BridgeRecordUsageByCountry to the section
"STATISTICS OPTIONS". Closes ticket 40323.
Changes in version 0.4.6.1-alpha - 2021-03-18
Tor 0.4.6.1-alpha is the first alpha release in the 0.4.6.x series. It
improves client circuit performance, adds missing features, and
improves some of our DoS handling and statistics reporting. It also
includes numerous smaller bugfixes.
Below are the changes since 0.4.5.7. (Note that this release DOES
include the fixes for the security bugs already fixed in 0.4.5.7.)
o Major features (control port, onion services):
- Add controller support for creating version 3 onion services with
client authorization. Previously, only v2 onion services could be
created with client authorization. Closes ticket 40084. Patch by
Neel Chauhan.
- When voting on a relay with a Sybil-like appearance, add the Sybil
flag when clearing out the other flags. This lets a relay operator
know why their relay hasn't been included in the consensus. Closes
ticket 40255. Patch by Neel Chauhan.
o Major features (metrics):
- Relays now report how overloaded they are in their extrainfo
documents. This information is controlled with the
OverloadStatistics torrc option, and it will be used to improve
decisions about the network's load balancing. Implements proposal
328; closes ticket 40222.
o Major features (relay, denial of service):
- Add a new DoS subsystem feature to control the rate of client
connections for relays. Closes ticket 40253.
o Major features (statistics):
- Relays now publish statistics about the number of v3 onion
services and volume of v3 onion service traffic, in the same
manner they already do for v2 onions. Closes ticket 23126.
o Major bugfixes (circuit build timeout):
- Improve the accuracy of our circuit build timeout calculation for
60%, 70%, and 80% build rates for various guard choices. We now
use a maximum likelihood estimator for Pareto parameters of the
circuit build time distribution, instead of a "right-censored
estimator". This causes clients to ignore circuits that never
finish building in their timeout calculations. Previously, clients
were counting such unfinished circuits as having the highest
possible build time value, when in reality these circuits most
likely just contain relays that are offline. We also now wait a
bit longer to let circuits complete for measurement purposes,
lower the minimum possible effective timeout from 1.5 seconds to
10ms, and increase the resolution of the circuit build time
histogram from 50ms bin widths to 10ms bin widths. Additionally,
we alter our estimate Xm by taking the maximum of the top 10 most
common build time values of the 10ms histogram, and compute Xm as
the average of these. Fixes bug 40168; bugfix on 0.2.2.14-alpha.
- Remove max_time calculation and associated warning from circuit
build timeout 'alpha' parameter estimation, as this is no longer
needed by our new estimator from 40168. Fixes bug 34088; bugfix
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on 0.2.2.9-alpha.
o Major bugfixes (signing key):
- In the tor-gencert utility, give an informative error message if
the passphrase given in `--create-identity-key` is too short.
Fixes bug 40189; bugfix on 0.2.0.1-alpha. Patch by Neel Chauhan.
o Minor features (bridge):
- We now announce the URL to Tor's new bridge status at
https://bridges.torproject.org/ when Tor is configured to run as a
bridge relay. Closes ticket 30477.
o Minor features (build system):
- New "make lsp" command to auto generate the compile_commands.json
file used by the ccls server. The "bear" program is needed for
this. Closes ticket 40227.
o Minor features (command-line interface):
- Add build informations to `tor --version` in order to ease
reproducible builds. Closes ticket 32102.
- When parsing command-line flags that take an optional argument,
treat the argument as absent if it would start with a '-'
character. Arguments in that form are not intelligible for any of
our optional-argument flags. Closes ticket 40223.
- Allow a relay operator to list the ed25519 keys on the command
line by adding the `rsa` and `ed25519` arguments to the
--list-fingerprint flag to show the respective RSA and ed25519
relay fingerprint. Closes ticket 33632. Patch by Neel Chauhan.
o Minor features (control port, stream handling):
- Add the stream ID to the event line in the ADDRMAP control event.
Closes ticket 40249. Patch by Neel Chauhan.
o Minor features (dormant mode):
- Add a new 'DormantTimeoutEnabled' option for coarse-grained
control over whether the client can become dormant from
inactivity. Most people won't need this. Closes ticket 40228.
- Change the DoS subsystem heartbeat line format to be more clear on
what has been detected/rejected, and which option is disabled (if
any). Closes ticket 40308.
- In src/core/mainloop/mainloop.c and src/core/mainloop/connection.c,
put brackets around IPv6 addresses in log messages. Closes ticket
40232. Patch by Neel Chauhan.
o Minor features (performance, windows):
- Use SRWLocks to implement locking on Windows. Replaces the
"critical section" locking implementation with the faster
SRWLocks, available since Windows Vista. Closes ticket 17927.
Patch by Daniel Pinto.
o Minor features (protocol, proxy support, defense in depth):
- Close HAProxy connections if they somehow manage to send us data
before we start reading. Closes another case of ticket 40017.
o Minor features (tests, portability):
- Port the hs_build_address.py test script to work with recent
versions of python. Closes ticket 40213. Patch from
Samanta Navarro.
o Minor features (vote document):
- Add a "stats" line to directory authority votes, to report various
statistics that authorities compute about the relays. This will
help us diagnose the network better. Closes ticket 40314.
- The configure script now shows whether or not lzma and zstd have
been used, not just if the enable flag was passed in. Fixes bug
40236; bugfix on 0.4.3.1-alpha.
o Minor bugfixes (compatibility):
- Fix a failure in the test cases when running on the "hppa"
architecture, along with a related test that might fail on other
architectures in the future. Fixes bug 40274; bugfix
on 0.2.5.1-alpha.
o Minor bugfixes (controller):
- Fix a "BUG" warning that would appear when a controller chooses
the first hop for a circuit, and that circuit completes. Fixes bug
40285; bugfix on 0.3.2.1-alpha.
o Minor bugfixes (directory authorities, voting):
- Add a new consensus method (31) to support any future changes that
authorities decide to make to the value of bwweightscale or
maxunmeasuredbw. Previously, there was a bug that prevented the
authorities from parsing these consensus parameters correctly under
most circumstances. Fixes bug 19011; bugfix on 0.2.2.10-alpha.
o Minor bugfixes (ipv6):
- Allow non-SOCKSPorts to disable IPv4, IPv6, and PreferIPv4. Some
rare configurations might break, but in this case you can disable
NoIPv4Traffic and NoIPv6Traffic as needed. Fixes bug 33607; bugfix
on 0.4.1.1-alpha. Patch by Neel Chauhan.
o Minor bugfixes (key generation):
- Do not require a valid torrc when using the `--keygen` argument to
generate a signing key. This allows us to generate keys on systems
or users which may not run Tor. Fixes bug 40235; bugfix on
0.2.7.2-alpha. Patch by Neel Chauhan.
o Minor bugfixes (onion services, logging):
- Downgrade the severity of a few rendezvous circuit-related
warnings from warning to info. Fixes bug 40207; bugfix on
0.3.2.1-alpha. Patch by Neel Chauhan.
o Minor bugfixes (relay):
- Reduce the compression level for data streaming from HIGH to LOW.
This should reduce the CPU and memory burden for directory caches.
Fixes bug 40301; bugfix on 0.3.5.1-alpha.
o Code simplification and refactoring:
- Remove the orconn_ext_or_id_map structure and related functions.
(Nothing outside of unit tests used them.) Closes ticket 33383.
Patch by Neel Chauhan.
o Removed features:
- As of this release, Tor no longer supports the old v2 onion
services. They were deprecated last July for security, and support
will be removed entirely later this year. We strongly encourage
everybody to migrate to v3 onion services. For more information,
see https://blog.torproject.org/v2-deprecation-timeline . Closes
ticket 40266. (NOTE: We accidentally released an earlier version
of the 0.4.6.1-alpha changelog without this entry. Sorry for
the confusion!)
o Code simplification and refactoring (metrics, DoS):
- Move the DoS subsystem into the subsys manager, including its
configuration options. Closes ticket 40261.
o Removed features (relay):
- Because DirPorts are only used on authorities, relays no longer
advertise them. Similarly, self-testing for DirPorts has been
disabled, since an unreachable DirPort is no reason for a relay
not to advertise itself. (Configuring a DirPort will still work,
for now.) Closes ticket 40282.
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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.
One of these vulnerabilities (TROVE-2021-001) would allow an attacker
who can send directory data to a Tor instance to force that Tor
instance to consume huge amounts of CPU. This is easiest to exploit
against authorities, since anybody can upload to them, but directory
caches could also exploit this vulnerability against relays or clients
when they download. The other vulnerability (TROVE-2021-002) only
affects directory authorities, and would allow an attacker to remotely
crash the authority with an assertion failure. Patches have already
been provided to the authority operators, to help ensure
network stability.
We recommend that everybody upgrade to one of the releases that fixes
these issues (0.3.5.14, 0.4.4.8, or 0.4.5.7) as they become available
to you.
This release also updates our GeoIP data source, and fixes a
compatibility issue.
o Major bugfixes (security, denial of service, backport from 0.4.5.7):
- Disable the dump_desc() function that we used to dump unparseable
information to disk. It was called incorrectly in several places,
in a way that could lead to excessive CPU usage. Fixes bug 40286;
bugfix on 0.2.2.1-alpha. This bug is also tracked as TROVE-2021-
001 and CVE-2021-28089.
- Fix a bug in appending detached signatures to a pending consensus
document that could be used to crash a directory authority. Fixes
bug 40316; bugfix on 0.2.2.6-alpha. Tracked as TROVE-2021-002
and CVE-2021-28090.
o Minor features (geoip data, backport from 0.4.5.7):
- We have switched geoip data sources. Previously we shipped IP-to-
country mappings from Maxmind's GeoLite2, but in 2019 they changed
their licensing terms, so we were unable to update them after that
point. We now ship geoip files based on the IPFire Location
Database instead. (See https://location.ipfire.org/ for more
information). This release updates our geoip files to match the
IPFire Location Database as retrieved on 2021/03/12. Closes
ticket 40224.
o Removed features (mallinfo deprecated, backport from 0.4.5.7):
- Remove mallinfo() usage entirely. Libc 2.33+ now deprecates it.
Closes ticket 40309.
Changes in version 0.4.4.8 - 2021-03-16
Tor 0.4.4.8 backports fixes for two important denial-of-service bugs
in earlier versions of Tor.
One of these vulnerabilities (TROVE-2021-001) would allow an attacker
who can send directory data to a Tor instance to force that Tor
instance to consume huge amounts of CPU. This is easiest to exploit
against authorities, since anybody can upload to them, but directory
caches could also exploit this vulnerability against relays or clients
when they download. The other vulnerability (TROVE-2021-002) only
affects directory authorities, and would allow an attacker to remotely
crash the authority with an assertion failure. Patches have already
been provided to the authority operators, to help ensure
network stability.
We recommend that everybody upgrade to one of the releases that fixes
these issues (0.3.5.14, 0.4.4.8, or 0.4.5.7) as they become available
to you.
This release also updates our GeoIP data source, and fixes a
compatibility issue.
o Major bugfixes (security, denial of service, backport from 0.4.5.7):
- Disable the dump_desc() function that we used to dump unparseable
information to disk. It was called incorrectly in several places,
in a way that could lead to excessive CPU usage. Fixes bug 40286;
bugfix on 0.2.2.1-alpha. This bug is also tracked as TROVE-2021-
001 and CVE-2021-28089.
- Fix a bug in appending detached signatures to a pending consensus
document that could be used to crash a directory authority. Fixes
bug 40316; bugfix on 0.2.2.6-alpha. Tracked as TROVE-2021-002
and CVE-2021-28090.
o Minor features (geoip data, backport from 0.4.5.7):
- We have switched geoip data sources. Previously we shipped IP-to-
country mappings from Maxmind's GeoLite2, but in 2019 they changed
their licensing terms, so we were unable to update them after that
point. We now ship geoip files based on the IPFire Location
Database instead. (See https://location.ipfire.org/ for more
information). This release updates our geoip files to match the
IPFire Location Database as retrieved on 2021/03/12. Closes
ticket 40224.
o Removed features (mallinfo deprecated, backport from 0.4.5.7):
- Remove mallinfo() usage entirely. Libc 2.33+ now deprecates it.
Closes ticket 40309.