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.
Without this message getting logged at 'WARN', it's hard to
contextualize the messages we get about compression bombs, so this
message should fix#40175.
I'm rate-limiting this, however, since it _could_ get spammy if
somebody on the network starts acting up. (Right now it should be
very quiet; I've asked Sebastian to check it, and he says that he
doesn't hit this message in practice.)
Closes#40175.
Cached_dir_t is a somewhat "legacy" kind of storage when used for
consensus documents, and it appears that there are cases when
changing our settings causes us to stop updating those entries.
This can cause trouble, as @arma found out in #40375, where he
changed his settings around, and consensus diff application got
messed up: consensus diffs were being _requested_ based on the
latest consensus, but were being (incorrectly) applied to a
consensus that was no longer the latest one.
This patch is a minimal fix for backporting purposes: it has Tor do
the same search when applying consensus diffs as we use to request
them. This should be sufficient for correct behavior.
There's a similar case in GETINFO handling; I've fixed that too.
Fixes#40375; bugfix on 0.3.1.1-alpha.
When seccomp sandbox is active, SAVECONF failed because it was not
able to save the backup files for torrc. This commit simplifies
the implementation of SAVECONF and sandbox by making it keep only
one backup of the configuration file.
Current counters are reset every heartbeat. This commit adds two
counters for the assigned and dropped onionskins that are not reset so
they can be exported onto the MetricsPort.
Closes#40387
Signed-off-by: David Goulet <dgoulet@torproject.org>
The connection type for the listener part was missing from the "is
connection a listener" function.
This lead to our periodic event that retries our listeners to keep
trying to bind() again on an already opened MetricsPort.
Closes#40370
Signed-off-by: David Goulet <dgoulet@torproject.org>
This resulted in the labels not being surrounded by double quotes and
thus Prometheus not liking it.
Signed-off-by: David Goulet <dgoulet@torproject.org>
Emit on the MetricsPort all the DNS statistics we have that is the total
number of queries seen and errors per record type.
Related to #40367
Signed-off-by: David Goulet <dgoulet@torproject.org>
We now keep track of all errors and total number of request seen. This
is so we can expose those values to the MetricsPort to help Exit
operators monitor the DNS requests and failures.
Related to #40367.
Signed-off-by: David Goulet <dgoulet@torproject.org>
This emits two events (read and write) of the total number that the
global connection limit was reached.
Related to #40367
Signed-off-by: David Goulet <dgoulet@torproject.org>
With this commit, a relay will emit metrics that give the total number
of sockets and total number of opened sockets.
Related to #40367
Signed-off-by: David Goulet <dgoulet@torproject.org>
With this commit, a relay now emits metrics event on the MetricsPort
related to how many onionskins were handled (processed or dropped) for
each handshake type.
Related to #40367
Signed-off-by: David Goulet <dgoulet@torproject.org>
With this commit, a relay now emits metrics event on the MetricsPort
related to the OOM invocation for:
- DNS cache
- GeoIP database
- Cell queues
- HSDir caches
Everytime the OOM is invoked, the number of bytes is added to the
metrics counter for that specific type of invocation.
Related to #40367
Signed-off-by: David Goulet <dgoulet@torproject.org>
The basic functions for the relay subsystem to expose metrics onto the
MetricsPort.
Part of #40367
Signed-off-by: David Goulet <dgoulet@torproject.org>
It is a common function that a lot of subsystem can use which is to
format a label so move it out of the HS subsystem into the more generic
metrics library.
Signed-off-by: David Goulet <dgoulet@torproject.org>
An entry can have multiple labels but only print once the comments at
the first one. This follows the Promtheus best practices.
Signed-off-by: David Goulet <dgoulet@torproject.org>
This change permits the newfstatat() system call, and fixes issues
40382 (and 40381).
This isn't a free change. From the commit:
// Libc 2.33 uses this syscall to implement both fstat() and stat().
//
// The trouble is that to implement fstat(fd, &st), it calls:
// newfstatat(fs, "", &st, AT_EMPTY_PATH)
// We can't detect this usage in particular, because "" is a pointer
// we don't control. And we can't just look for AT_EMPTY_PATH, since
// AT_EMPTY_PATH only has effect when the path string is empty.
//
// So our only solution seems to be allowing all fstatat calls, which
// means that an attacker can stat() anything on the filesystem. That's
// not a great solution, but I can't find a better one.
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.
Turns out that passing client authorization keys to ADD_ONION for v3 was
not working because we were not setting the "is_client_auth_enabled"
flag to true once the clients were configured. This lead to the
descriptor being encoded without the clients.
This patch removes that flag and instead adds an inline function that
can be used to check if a given service has client authorization
enabled.
This will be much less error prone of needing to keep in sync the client
list and a flag instead.
Fixes#40378
Signed-off-by: David Goulet <dgoulet@torproject.org>
This function has been a no-op since Libevent 2.0.4-alpha, when
libevent got an arc4random() implementation. Libevent has finally
removed it, which will break our compilation unless we stop calling
it. (This is currently breaking compilation in OSS-fuzz.)
Closes#40371.
This is related to ticket #40360 which found this problem when a Bridge entry
with a transport name (let say obfs4) is set without a fingerprint:
Bridge obfs4 <IP>:<PORT> cert=<...> iat-mode=0
(Notice, no fingerprint between PORT and "cert=")
Problem: commit 09c6d03246 added a check in
get_sampled_guard_for_bridge() that would return NULL if the selected bridge
did not have a valid transport name (that is the Bridge transport name that
corresponds to a ClientTransportPlugin).
Unfortuantely, this function is also used when selecting our eligible guards
which is done *before* the transport list is populated and so the added check
for the bridge<->transport name is querying an empty list of transports
resulting in always returning NULL.
For completion, the logic is: Pick eligible guards (use bridge(s) if need be)
then for those, initiate a connection to the pluggable transport proxy and
then populate the transport list once we've connected.
Back to get_sampled_guard_for_bridge(). As said earlier, it is used when
selecting our eligible guards in a way that prevents us from selecting
duplicates. In other words, if that function returns non-NULL, the selection
continues considering the bridge was sampled before. But if it returns NULL,
the relay is added to the eligible list.
This bug made it that our eligible guard list was populated with the *same*
bridge 3 times like so (remember no fingerprint):
[info] entry_guards_update_primary(): Primary entry guards have changed. New primary guard list is:
[info] entry_guards_update_primary(): 1/3: [bridge] ($0000000000000000000000000000000000000000)
[info] entry_guards_update_primary(): 2/3: [bridge] ($0000000000000000000000000000000000000000)
[info] entry_guards_update_primary(): 3/3: [bridge] ($0000000000000000000000000000000000000000)
When tor starts, it will find the bridge fingerprint by connecting to it and
will then update the primary guard list by calling
entry_guard_learned_bridge_identity() which then goes and update only 1 single
entry resulting in this list:
[debug] sampled_guards_update_consensus_presence(): Sampled guard [bridge] ($<FINGERPRINT>) is still listed.
[debug] sampled_guards_update_consensus_presence(): Sampled guard [bridge] ($0000000000000000000000000000000000000000) is still listed.
[debug] sampled_guards_update_consensus_presence(): Sampled guard [bridge] ($0000000000000000000000000000000000000000) is still listed.
And here lies the problem, now tor is stuck attempting to wait for a valid
descriptor for at least 2 guards where the second one is a bunch of zeroes and
thus tor will never fully bootstraps:
[info] I learned some more directory information, but not enough to build a
circuit: We're missing descriptors for 1/2 of our primary entry guards
(total microdescriptors: 6671/6703). That's ok. We will try to fetch missing
descriptors soon.
Now, why passing the fingerprint then works? This is because the list of
guards contains 3 times the same bridge but they all have a fingerprint and so
the descriptor can be found and tor can bootstraps.
The solution here is to entirely remove the transport name check in
get_sampled_guard_for_bridge() since the transport_list is empty at that
point. That way, the eligible guard list only gets 1 entry, the bridge, and
can then go on to bootstrap properly.
It is OK to do so since when launching a bridge descriptor fetch, we validate
that the bridge transport name is OK and thus avoid connecting to a bridge
without a ClientTransportPlugin. If we wanted to keep the check in place, we
would need to populate the transport_list much earlier and this would require
a much bigger refactoring.
Fixes#40360
Signed-off-by: David Goulet <dgoulet@torproject.org>
When seccomp sandbox is active, SAVECONF failed because it was not
able to save the backup files for torrc. This commit simplifies
the implementation of SAVECONF and sandbox by making it keep only
one backup of the configuration file.
On Linux systems, glob automatically ignores the errors ENOENT and
ENOTDIR because they are expected during glob expansion. But BSD
systems do not ignore these, resulting in glob failing when globs
expand to invalid paths. This is fixed by adding a custom error
handler that ignores only these two errors and removing the
GLOB_ERR flag as it makes glob fail even if the error handler
ignores the error and is unnecessary as the error handler will
make glob fail on all other errors anyway.
