Commit e80893e51b made tor call
hs_service_intro_circ_has_closed() when we mark for close a circuit.
When we cleanup intro points, we iterate over the descriptor's map of intro
points and we can possibly mark for close a circuit. This was problematic
because we would MAP_DEL_CURRENT() the intro point then free it and finally
mark for close the circuit which would lookup the intro point that we just
free in the map we are iterating over.
This can't be done and leads to a use-after-free because the intro point will
be returned successfully due to the fact that we are still in the loop
iterating. In other words, MAP_DEL_CURRENT() followed by a digest256map_get()
of the same object should never be done in the same loop.
Fixes#24595
Signed-off-by: David Goulet <dgoulet@torproject.org>
In KIST, we could have a small congestion window value than the unacked
packets leading to a integer overflow which leaves the tcp_space value to be
humongous.
This has no security implications but it results in KIST scheduler allowing to
send cells on a potentially saturated connection.
Found by #24423. Fixes#24590.
Signed-off-by: David Goulet <dgoulet@torproject.org>
Previously, circuit_stream_is_being_handled incorrectly reported
that (1) an exit port was "handled" by a circuit regardless of
whether the circuit was already isolated in some way, and
(2) that a stream could be "handled" by a circuit even if their
isolation settings were incompatible.
As a result of (1), in Tor Browser, circuit_get_unhandled_ports was
reporting that all ports were handled even though all non-internal
circuits had already been isolated by a SOCKS username+password.
Therefore, circuit_predict_and_launch_new was declining to launch
new exit circuits. Then, when the user visited a new site in Tor
Browser, a stream with new SOCKS credentials would be initiated,
and the stream would have to wait while a new circuit with those
credentials could be built. That wait was making the
time-to-first-byte longer than it needed to be.
Now, clean, not-yet-isolated circuit(s) will be automatically
launched ahead of time and be ready for use whenever a new stream
with new SOCKS credentials (or other isolation criteria) is
initiated.
Fixes bug 18859. Thanks to Nick Mathewson for improvements.
First, hs_service_intro_circ_has_closed() is now called in circuit_mark_for
close() because the HS subsystem needs to learn when an intro point is
actually not established anymore as soon as possible. There is a time window
between a close and a free.
Second, when we mark for close, we also remove it from the circuitmap because
between the close and the free, a service can launch an new circuit to that
same intro point and thus register it which only succeeds if the intro point
authentication key is not already in the map.
However, we still do a remove from the circuitmap in circuit_free() in order
to also cleanup the circuit if it wasn't marked for close prior to the free.
Fixes#23603
Signed-off-by: David Goulet <dgoulet@torproject.org>
The hs_service_intro_circ_has_closed() was removing intro point objects if too
many retries.
We shouldn't cleanup those objects in that function at all but rather let
cleanup_intro_points() do its job and clean it properly.
This was causing an issue in #23603.
Furthermore, this moves the logic of remembering failing intro points in the
cleanup_intro_points() function which should really be the only function to
know when to cleanup and thus when an introduction point should be remembered
as a failed one.
Fixes#23603
Signed-off-by: David Goulet <dgoulet@torproject.org>
In the KIST main loop, if the channel happens to be not opened, set its state
to IDLE so we can release it properly later on. Prior to this fix, the channel
was in PENDING state, removed from the channel pending list and then kept in
that state because it is not opened.
This bug was introduced in commit dcabf801e5 for
which we made the scheduler loop not consider unopened channel.
This has no consequences on tor except for an annoying but harmless BUG()
warning.
Fixes#24502
Signed-off-by: David Goulet <dgoulet@torproject.org>
Some platforms don't have good monotonic time support so don't warn when the
diff between the last run of the scheduler time and now is negative. The
scheduler recovers properly from this so no need to be noisy.
Fixes#23696
Signed-off-by: David Goulet <dgoulet@torproject.org>
Fortunately, use_cached_ipv4_answers was already 0, so we wouldn't
actually use this info, but it's best not to have it.
Fixes bug 24050; bugfix on 0.2.6.3-alpha
TROVE-2017-12. Severity: Medium
When choosing a random node for a circuit, directly use our router
descriptor to exclude ourself instead of the one in the global
descriptor list. That list could be empty because tor could be
downloading them which could lead to not excluding ourself.
Closes#21534
TROVE-2017-12. Severity: Medium
Thankfully, tor will close any circuits that we try to extend to
ourselves so this is not problematic but annoying.
Part of #21534.
TROVE-2017-13. Severity: High.
In the unlikely case that a hidden service could be missing intro circuit(s),
that it didn't have enough directory information to open new circuits and that
an intro point was about to expire, a use-after-free is possible because of
the intro point object being both in the retry list and expiring list at the
same time.
The intro object would get freed after the circuit failed to open and then
access a second time when cleaned up from the expiring list.
Fixes#24313
Going from 4 hours to 24 hours in order to try reduce the efficiency of guard
discovery attacks.
Closes#23856
Signed-off-by: David Goulet <dgoulet@torproject.org>
This applies the changes in 23524 to num_usable_bridges(), because it has
replaced any_bridge_descriptors_known().
The original changes file still applies.
Stop checking for bridge descriptors when we actually want to know if
any bridges are usable. This avoids potential bootstrapping issues.
Fixes bug 24367; bugfix on 0.2.0.3-alpha.
Stop stalling when bridges are changed at runtime. Stop stalling when
old bridge descriptors are cached, but they are not in use.
Fixes bug 24367; bugfix on 23347 in 0.3.2.1-alpha.
We used to check whether we have enough filtered guards (guard set when
torrc is applied) but that's not good enough, since that might be bad in
some cases where many guards are not reachable (might cause overblocking
and hence reacahbility issues).
We now check if we have enough reachable filtered guards before applying
md restrictions which should prevent overblocking.
Previously, if store_multiple() reported a partial success, we would
store all the handles it gave us as if they had succeeded. But it's
possible for the diff to be only partially successful -- for
example, if LZMA failed but the other compressors succeeded.
Fixes bug 24086; bugfix on 0.3.1.1-alpha.
If we can't read a file because of an FS issue, we say "we can't
read that" and move on. But if we can't read it because it's empty,
because it has no labels, or because its labels are misformatted, we
should remove it.
Fixes bug 24099; bugfix on 0.3.1.1-alpha.
A circuit with purpose C_INTRODUCING means that its state is opened but the
INTRODUCE1 cell hasn't been sent yet. We shouldn't consider that circuit when
looking for timing out "building circuit". We have to wait on the rendezvous
circuit to be opened before sending that cell so the intro circuit needs to be
kept alive for at least that period of time.
This patch makes that the purpose C_INTRODUCING is ignored in the
circuit_expire_building() which means that we let the circuit idle timeout
take care of it if we end up never using it.
Fixes#23681
Signed-off-by: David Goulet <dgoulet@torproject.org>
When we close a connection via connection_close_immediately, we kill
its events immediately. But if it had been blocked on bandwidth
read/write, we could try to re-add its (nonexistent) events later
from connection_bucket_refill -- if we got to that callback before
we swept the marked connections.
Fixes bug 24167. Fortunately, this hasn't been a crash bug since we
introduced connection_check_event in 0.2.9.10, and backported it.
This is a bugfix on commit 89d422914a, I believe, which
appeared in Tor 0.1.0.1-rc.
Commit 56c5e282a7 suppressed that same log
statement in directory_info_has_arrived() for microdescriptors so do the same
for the descriptors. As the commit says, we already have the bootstrap
progress for this.
Fixes#23861
Signed-off-by: David Goulet <dgoulet@torproject.org>
evdns is allowed to give us unrecognized object types; it is allowed
to give us non-IPv4 answer types, and it is (even) allowed to give
us empty answers without an error.
Closes ticket 24097.
