This issue was reported by Jann Horn part of Google's Project Zero.
Jann's one-sentence summary: entry/middle relays can spoof RELAY_END cells on
half-closed streams, which can lead to stream confusion between OP and
exit.
Fixes#40389
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.
As of GCC 11.1.1, the compiler warns us about code like this:
if (a)
b;
c;
and that's a good thing: we wouldn't want to "goto fail". But we
had an instance if this in circuituse.c, which was making our
compilation sad.
Fixes bug 40380; bugfix on 0.3.0.1-alpha.
Fortunately, our tor_free() is setting the variable to NULL after so we were
in a situation where NULL was always used instead of the transport name.
This first appeared in 894ff2dc84 and results in
basically no bridge with a transport being able to use DoS defenses.
Fixes#40345
Signed-off-by: David Goulet <dgoulet@torproject.org>
We were looking for the first instance of "directory-signature "
when instead the correct behavior is to look for the first instance
of "directory-signature " at the start of a line.
Unfortunately, this can be exploited as to crash authorities while
they're voting.
Fixes#40316; bugfix on 0.2.2.4-alpha. This is TROVE-2021-002,
also tracked as CVE-2021-28090.
It can be called with strings that should have been
length-delimited, but which in fact are not. This can cause a
CPU-DoS bug or, in a worse case, a crash.
Since this function isn't essential, the best solution for older
Tors is to just turn it off.
Fixes bug 40286; bugfix on 0.2.2.1-alpha when dump_desc() was
introduced.
Exit relays now reject exit attempts to known relay addresses + ORPort and
also to authorities on the ORPort and DirPort.
Closes#2667
Signed-off-by: David Goulet <dgoulet@torproject.org>
Nick Mathewson
George Kadianakis
David Goulet
Alexander Færøy
Roger Dingledine