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.
Due to #23662 this can happen under natural causes and does not disturb
the functionality of the service. This is a simple 0.3.2 fix for now,
and we plan to fix this properly in 0.3.3.
On failure to upload, the HS_DESC event would report "UPLOAD_FAILED" as the
Action but it should have reported "FAILED" according to the spec.
Fixes#24230
Signed-off-by: David Goulet <dgoulet@torproject.org>
Commit e67f4441eb introduced a safeguard against
using an uninitialized voting schedule object. However, the dirvote_act() code
was looking roughly at the same thing to know if it had to compute the timings
before voting with this condition:
if (!voting_schedule.voting_starts) {
...
dirvote_recalculate_timing(options, now);
}
The sr_init() function is called very early and goes through the safeguard
thus the voting schedule is always initilized before the first vote.
That first vote is a crucial one because we need to have our voting schedule
aligned to the "now" time we are about to use for voting. Then, the schedule
is updated when we publish our consensus or/and when we set a new consensus.
From that point on, we only want to update the voting schedule through that
code flow.
This "created_on_demand" is indicating that the timings have been recalculated
on demand by another subsystem so if it is flagged, we know that we need to
ignore its values before voting.
Fixes#24186
Signed-off-by: David Goulet <dgoulet@torproject.org>
When we have fewer than 15 descriptors to fetch, we will delay the
fetch for a little while. That's fine, if we can go ahead and build
circuits... but if not, it's a poor choice indeed.
Fixes bug 23985; bugfix on 0.1.1.11-alpha.
In 0.3.0.3-alpha, when we made primary guard descriptors necessary
for circuit building, this situation got worse.
When calculating the fraction of nodes that have descriptors, and all
all nodes in the network have zero bandwidths, count the number of nodes
instead.
Fixes bug 23318; bugfix on 0.2.4.10-alpha.
Back in 0.2.4.3-alpha (e106812a77), when we switched from using
double to using uint64 for selecting by bandwidth, I got the math
wrong: I should have used llround(x), or (uint64_t)(x+0.5), but
instead I wrote llround(x+0.5). That means we would always round
up, rather than rounding to the closest integer
Fixes bug 23318; bugfix on 0.2.4.3-alpha.
The flush cells process can close a channel if the connection write fails but
still return that it flushed at least one cell. This is due because the error
is not propagated up the call stack so there is no way of knowing if the flush
actually was successful or not.
Because this would require an important refactoring touching multiple
subsystems, this patch is a bandaid to avoid the KIST scheduler to handle
closed channel in its loop.
Bandaid on #23751.
Signed-off-by: David Goulet <dgoulet@torproject.org>
dirvote_get_next_valid_after_time() is the only public function that uses the
voting schedule outside of the dirvote subsystem so if it is zeroed,
recalculate its timing if we can that is if a consensus exists.
Part of #24161
Signed-off-by: David Goulet <dgoulet@torproject.org>
Because the HS and SR subsystems can use the voting schedule early (with the
changes in #23623 making the SR subsystem using the static voting schedule
object), we need to recalculate the schedule very early when setting the new
consensus.
Fixes#24161
Signed-off-by: David Goulet <dgoulet@torproject.org>
If it decrypts something that turns out to start with a NUL byte,
then decrypt_desc_layer() will return 0 to indicate the length of
its result. But 0 also indicates an error, which causes the result
not to be freed by decrypt_desc_layer()'s callers.
Since we're trying to stabilize 0.3.2.x, I've opted for the simpler
possible fix here and made it so that an empty decrypted string will
also count as an error.
Fixes bug 24150 and OSS-Fuzz issue 3994.
The original bug was present but unreachable in 0.3.1.1-alpha. I'm
calling this a bugfix on 0.3.2.1-alpha since that's the first version
where you could actually try to decrypt these descriptors.
The node_get_ed25519_id() warning can actually be triggered by a relay flagged
with NoEdConsensus so instead of triggering a warning on all relays of the
network, downgrade it to protocol warning.
Fixes#24025
Signed-off-by: David Goulet <dgoulet@torproject.org>
When a BUG() occurs, this macro will print extra information about the state
of the scheduler and the given channel if any. This will help us greatly to
fix future bugs in the scheduler especially when they occur rarely.
Fixes#23753
Signed-off-by: David Goulet <dgoulet@torproject.org>
They are not yet implemented: they will upload descriptors, but won't be
able to rendezvous, because IPv6 addresses in link specifiers are ignored.
Part of #23820.
The previous version of this function had the following issues:
* it didn't check if the extend_info contained an IPv6 address,
* it didn't check if the ed25519 identity key was valid.
But we can't add IPv6 support in a bugfix release.
Instead, BUG() if the address is an IPv6 address, so we always put IPv4
addresses in link specifiers. And ignore missing ed25519 identifiers,
rather than generating an all-zero link specifier.
This supports v3 hidden services on IPv4, dual-stack, and IPv6, and
v3 single onion services on IPv4 only.
Part of 23820, bugfix on 0.3.2.1-alpha.
When the directory information changes, callback to the HS client subsystem so
it can check if any pending SOCKS connections are waiting for a descriptor. If
yes, attempt a refetch for those.
Fixes#23762
Signed-off-by: David Goulet <dgoulet@torproject.org>
Because the HS subsystem needs the voting schedule to compute time period, we
need all tor type to do that.
Part of #23623
Signed-off-by: David Goulet <dgoulet@torproject.org>
The new decryption function performs no decryption, skips the salt,
and doesn't check the mac. This allows us to fuzz the
hs_descriptor.c code using unencrypted descriptor test, and exercise
more of the code.
Related to 21509.
The exposed get_voting_schedule() allocates and return a new object everytime
it is called leading to an awful lot of memory allocation when getting the
start time of the current round which is done for each node in the consensus.
Closes#23623
Signed-off-by: David Goulet <dgoulet@torproject.org>
If the intro point supports ed25519 link authentication, make sure we don't
have a zeroed key which would lead to a failure to extend to it.
We already check for an empty key if the intro point does not support it so
this makes the check on the key more consistent and symmetric.
Fixes#24002
Signed-off-by: David Goulet <dgoulet@torproject.org>
The previous version of these functions had the following issues:
* they can't supply both the IPv4 and IPv6 addresses in link specifiers,
* they try to fall back to a 3-hop path when the address for a direct
connection is unreachable, but this isn't supported by
launch_rendezvous_point_circuit(), so it fails.
But we can't fix these things in a bugfix release.
Instead, always put IPv4 addresses in link specifiers.
And if a v3 single onion service can't reach any intro points, fail.
This supports v3 hidden services on IPv4, dual-stack, and IPv6, and
v3 single onion services on IPv4 only.
Part of 23820, bugfix on 0.3.2.1-alpha.
The previous version of this function has the following issues:
* it doesn't choose between IPv4 and IPv6 addresses correctly, and
* it doesn't fall back to a 3-hop path when the address for a direct
connection is unreachable.
But we can't fix these things in a bugfix release.
Instead, treat IPv6 addresses like any other unrecognised link specifier
and ignore them. If there is no IPv4 address, return NULL.
This supports v3 hidden services on IPv4, dual-stack, and IPv6, and
v3 single onion services on IPv4 only.
Part of 23820, bugfix on 0.3.2.1-alpha.
Turns out that when reloading a tor configured with hidden service(s), we
weren't copying all the needed information between the old service object to
the new one.
For instance, the desc_is_dirty timestamp wasn't which could lead to the
service uploading its desriptor much later than it would need to.
The replaycache wasn't also moved over and some intro point information as
well.
Fixes#23790
Signed-off-by: David Goulet <dgoulet@torproject.org>
Bridge relays can use it to add a "bridge-distribution-request" line
to their bridge descriptor, which tells BridgeDB how they'd like their
bridge address to be given out.
Implements tickets 18329.
Fixes bug 23908; bugfix on 0.3.1.6-rc when we made the keypin
failure message really long.
Backport from 0.3.2's 771fb7e7ba,
where arma said "get rid of the scary 256-byte-buf landmine".
Create a function that tells us if we can fetch or not the descriptor for the
given service key.
No behavior change. Mostly moving code but with a slight change so the
function can properly work by returning a boolean and also a possible fetch
status code.
Signed-off-by: David Goulet <dgoulet@torproject.org>
