(Also, 0.3.0.7 was released last week. If you didn't know, you should
subscribe to tor-announcements.)
Hi, all!
You can find the source code for Tor 0.3.0.1-alpha www.torrpoject.org
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 series to hit Tor Browser alpha releases some
time in the middle of June.
===
Changes in version 0.3.1.1-alpha - 2017-05-22
Tor 0.3.1.1-alpha is the first release in the 0.3.1.x series. It
reduces the bandwidth usage for Tor's directory protocol, adds some
basic padding to resist netflow-based traffic analysis and to serve as
the basis of other padding in the future, and adds rust support to the
build system.
It also contains numerous other small features and improvements to
security, correctness, and performance.
Below are the changes since 0.3.0.7.
o Major features (directory protocol):
- Tor relays and authorities can now serve clients an abbreviated
version of the consensus document, containing only the changes
since an older consensus document that the client holds. Clients
now request these documents when available. When both client and
server use this new protocol, they will use far less bandwidth (up
to 94% less) to keep the client's consensus up-to-date. Implements
proposal 140; closes ticket 13339. Based on work by Daniel MartÃ.
- Tor can now compress directory traffic with lzma or with zstd
compression algorithms, which can deliver better bandwidth
performance. Because lzma is computationally expensive, it's only
used for documents that can be compressed once and served many
times. Support for these algorithms requires that tor is built
with the libzstd and/or liblzma libraries available. Implements
proposal 278; closes ticket 21662.
- Relays now perform the more expensive compression operations, and
consensus diff generation, in worker threads. This separation
avoids delaying the main thread when a new consensus arrives.
o Major features (experimental):
- Tor can now build modules written in Rust. To turn this on, pass
the "--enable-rust" flag to the configure script. It's not time to
get excited yet: currently, there is no actual Rust functionality
beyond some simple glue code, and a notice at startup to tell you
that Rust is running. Still, we hope that programmers and
packagers will try building Tor with Rust support, so that we can
find issues and solve portability problems. Closes ticket 22106.
o Major features (traffic analysis resistance):
- Connections between clients and relays now send a padding cell in
each direction every 1.5 to 9.5 seconds (tunable via consensus
parameters). This padding will not resist specialized
eavesdroppers, but it should be enough to make many ISPs' routine
network flow logging less useful in traffic analysis against
Tor users.
Padding is negotiated using Tor's link protocol, so both relays
and clients must upgrade for this to take effect. Clients may
still send padding despite the relay's version by setting
ConnectionPadding 1 in torrc, and may disable padding by setting
ConnectionPadding 0 in torrc. Padding may be minimized for mobile
users with the torrc option ReducedConnectionPadding. Implements
Proposal 251 and Section 2 of Proposal 254; closes ticket 16861.
- Relays will publish 24 hour totals of padding and non-padding cell
counts to their extra-info descriptors, unless PaddingStatistics 0
is set in torrc. These 24 hour totals are also rounded to
multiples of 1.
o Major bugfixes (connection usage):
- We use NETINFO cells to try to determine if both relays involved
in a connection will agree on the canonical status of that
connection. We prefer the connections where this is the case for
extend cells, and try to close connections where relays disagree
on their canonical status early. Also, we now prefer the oldest
valid connection for extend cells. These two changes should reduce
the number of long-term connections that are kept open between
relays. Fixes bug 17604; bugfix on 0.2.5.5-alpha.
- Relays now log hourly statistics (look for
"channel_check_for_duplicates" lines) on the total number of
connections to other relays. If the number of connections per
relay is unexpectedly large, this log message is at notice level.
Otherwise it is at info.
o Major bugfixes (entry guards):
- Don't block bootstrapping when a primary bridge is offline and we
can't get its descriptor. Fixes bug 22325; fixes one case of bug
21969; bugfix on 0.3.0.3-alpha.
o Major bugfixes (linux TPROXY support):
- Fix a typo that had prevented TPROXY-based transparent
