[tor-talk] Tor 0.3.0.1-alpha is out!
nickm at torproject.org
Mon Dec 19 19:19:17 UTC 2016
(Also, Tor 0.2.9.8 and Tor 0.2.8.12 are out. If you didn't know, you
should subscribe to tor-announce an/or read the Tor blog!)
You can find the Tor 0.3.0.1-alpha source on the website at the usual
place. It's an alpha, so please expect plenty of bugs, and be ready
to report them. Packages should be out over the next weeks -- I'd
expect this to hit Tor Browser alphas by the end of January or so.
Changes in version 0.3.0.1-alpha - 2016-12-19
Tor 0.3.0.1-alpha is the first alpha release in the 0.3.0 development
series. It strengthens Tor's link and circuit handshakes by
identifying relays by their Ed25519 keys, improves the algorithm that
clients use to choose and maintain their list of guards, and includes
additional backend support for the next-generation hidden service
design. It also contains numerous other small features and
improvements to security, correctness, and performance.
Below are the changes since 0.2.9.8.
o Major features (guard selection algorithm):
- Tor's guard selection algorithm has been redesigned from the
ground up, to better support unreliable networks and restrictive
sets of entry nodes, and to better resist guard-capture attacks by
hostile local networks. Implements proposal 271; closes
o Major features (next-generation hidden services):
- Relays can now handle v3 ESTABLISH_INTRO cells as specified by
prop224 aka "Next Generation Hidden Services". Service and clients
don't use this functionality yet. Closes ticket 19043. Based on
initial code by Alec Heifetz.
- Relays now support the HSDir version 3 protocol, so that they can
can store and serve v3 descriptors. This is part of the next-
generation onion service work detailled in proposal 224. Closes
o Major features (protocol, ed25519 identity keys):
- Relays now use Ed25519 to prove their Ed25519 identities and to
one another, and to clients. This algorithm is faster and more
secure than the RSA-based handshake we've been doing until now.
Implements the second big part of proposal 220; Closes
- Clients now support including Ed25519 identity keys in the EXTEND2
cells they generate. By default, this is controlled by a consensus
parameter, currently disabled. You can turn this feature on for
testing by setting ExtendByEd25519ID in your configuration. This
might make your traffic appear different than the traffic
generated by other users, however. Implements part of ticket
15056; part of proposal 220.
- Relays now understand requests to extend to other relays by their
Ed25519 identity keys. When an Ed25519 identity key is included in
an EXTEND2 cell, the relay will only extend the circuit if the
other relay can prove ownership of that identity. Implements part
of ticket 15056; part of proposal 220.
o Major bugfixes (scheduler):
- Actually compare circuit policies in ewma_cmp_cmux(). This bug
caused the channel scheduler to behave more or less randomly,
rather than preferring channels with higher-priority circuits.
Fixes bug 20459; bugfix on 0.2.6.2-alpha.
o Minor features (controller):
- When HSFETCH arguments cannot be parsed, say "Invalid argument"
rather than "unrecognized." Closes ticket 20389; patch from
o Minor features (diagnostic, directory client):
- Warn when we find an unexpected inconsistency in directory
download status objects. Prevents some negative consequences of
o Minor features (directory authority):
- Add a new authority-only AuthDirTestEd25519LinkKeys option (on by
default) to control whether authorities should try to probe relays
by their Ed25519 link keys. This option will go away in a few
releases--unless we encounter major trouble in our ed25519 link
protocol rollout, in which case it will serve as a safety option.
o Minor features (directory cache):
- Relays and bridges will now refuse to serve the consensus they
have if they know it is too old for a client to use. Closes
o Minor features (ed25519 link handshake):
- Advertise support for the ed25519 link handshake using the
subprotocol-versions mechanism, so that clients can tell which
relays can identity themselves by Ed25519 ID. Closes ticket 20552.
o Minor features (fingerprinting resistence, authentication):
- Extend the length of RSA keys used for TLS link authentication to
2048 bits. (These weren't used for forward secrecy; for forward
secrecy, we used P256.) Closes ticket 13752.
o Minor features (infrastructure):
- Implement smartlist_add_strdup() function. Replaces the use of
smartlist_add(sl, tor_strdup(str)). Closes ticket 20048.
o Minor bugfixes (client):
- When clients that use bridges start up with a cached consensus on
disk, they were ignoring it and downloading a new one. Now they
use the cached one. Fixes bug 20269; bugfix on 0.2.3.12-alpha.
o Minor bugfixes (configuration):
- Accept non-space whitespace characters after the severity level in
the `Log` option. Fixes bug 19965; bugfix on 0.2.1.1-alpha.
- Support "TByte" and "TBytes" units in options given in bytes.
"TB", "terabyte(s)", "TBit(s)" and "terabit(s)" were already
supported. Fixes bug 20622; bugfix on 0.2.0.14-alpha.
o Minor bugfixes (consensus weight):
- Add new consensus method that initializes bw weights to 1 instead
of 0. This prevents a zero weight from making it all the way to
the end (happens in small testing networks) and causing an error.
Fixes bug 14881; bugfix on 0.2.2.17-alpha.
o Minor bugfixes (descriptors):
- Correctly recognise downloaded full descriptors as valid, even
when using microdescriptors as circuits. This affects clients with
FetchUselessDescriptors set, and may affect directory authorities.
Fixes bug 20839; bugfix on 0.2.3.2-alpha.
o Minor bugfixes (directory system):
- Download all consensus flavors, descriptors, and authority
certificates when FetchUselessDescriptors is set, regardless of
whether tor is a directory cache or not. Fixes bug 20667; bugfix
on all recent tor versions.
- Bridges and relays now use microdescriptors (like clients do)
rather than old-style router descriptors. Now bridges will blend
in with clients in terms of the circuits they build. Fixes bug
6769; bugfix on 0.2.3.2-alpha.
o Minor bugfixes (ed25519 certificates):
- Correctly interpret ed25519 certificates that would expire some
time after 19 Jan 2038. Fixes bug 20027; bugfix on 0.2.7.2-alpha.
o Minor bugfixes (hidden services):
- Stop ignoring misconfigured hidden services. Instead, refuse to
start tor until the misconfigurations have been corrected. Fixes
bug 20559; bugfix on multiple commits in 0.2.7.1-alpha
o Minor bugfixes (memory leak at exit):
- Fix a small harmless memory leak at exit of the previously unused
RSA->Ed identity cross-certificate. Fixes bug 17779; bugfix
o Minor bugfixes (util):
- When finishing writing a file to disk, if we were about to replace
the file with the temporary file created before and we fail to
replace it, remove the temporary file so it doesn't stay on disk.
Fixes bug 20646; bugfix on tor-0.2.0.7-alpha. Patch by fk.
o Minor bugfixes (Windows):
- Check for getpagesize before using it to mmap files. This fixes
compilation in some MinGW environments. Fixes bug 20530; bugfix on
0.1.2.1-alpha. Reported by "ice".
o Code simplification and refactoring:
- Abolish all global guard context in entrynodes.c; replace with new
guard_selection_t structure as preparation for proposal 271.
Closes ticket 19858.
- Introduce rend_service_is_ephemeral() that tells if given onion
service is ephemeral. Replace unclear NULL-checkings for service
directory with this function. Closes ticket 20526.
- Extract magic numbers in circuituse.c into defined variables.
- Refactor circuit_is_available_for_use to remove unnecessary check.
- Refactor circuit_predict_and_launch_new for readability and
testability. Closes ticket 18873.
- Refactor large if statement in purpose_needs_anonymity to use
switch statement instead. Closes part of ticket 20077.
- Refactor the hashing API to return negative values for errors, as
is done as throughout the codebase. Closes ticket 20717.
- Remove data structures that were used to index or_connection
objects by their RSA identity digests. These structures are fully
redundant with the similar structures used in the
- Remove duplicate code in the channel_write_*cell() functions.
Closes ticket 13827; patch from Pingl.
- Remove redundant behavior of is_sensitive_dir_purpose, refactor to
use only purpose_needs_anonymity. Closes part of ticket 20077.
- The code to generate and parse EXTEND and EXTEND2 cells has been
replaced with code automatically generated by the
- Include the "TBits" unit in Tor's man page. Fixes part of bug
20622; bugfix on tor-0.2.5.1-alpha.
- Change '1' to 'weight_scale' in consensus bw weights calculation
comments, as that is reality. Closes ticket 20273. Patch
- Correct the value for AuthDirGuardBWGuarantee in the manpage, from
250 KBytes to 2 MBytes. Fixes bug 20435; bugfix
- Stop the man page from incorrectly stating that HiddenServiceDir
must already exist. Fixes 20486.
- Clarify that when ClientRejectInternalAddresses is enabled (which
is the default), multicast DNS hostnames for machines on the local
network (of the form *.local) are also rejected. Closes
o Removed features:
- The AuthDirMaxServersPerAuthAddr option no longer exists: The same
limit for relays running on a single IP applies to authority IP
addresses as well as to non-authority IP addresses. Closes
- The UseDirectoryGuards torrc option no longer exists: all users
that use entry guards will also use directory guards. Related to
proposal 271; implements part of ticket 20831.
- New unit tests for tor_htonll(). Closes ticket 19563. Patch
- Perform the coding style checks when running the tests and fail
when coding style violations are found. Closes ticket 5500.
- Add tests for networkstatus_compute_bw_weights_v10.
- Add unit tests circuit_predict_and_launch_new.
- Extract dummy_origin_circuit_new so it can be used by other
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