We currently assume that the only way for Tor to listen on ports in the
privileged port range (1 to 1023), on Linux, is if we are granted the
NET_BIND_SERVICE capability. Today on Linux, it's possible to specify
the beginning of the unprivileged port range using a sysctl
configuration option. Docker (and thus the CI service Tor uses) recently
changed this sysctl value to 0, which causes our tests to fail as they
assume that we should NOT be able to bind to a privileged port *without*
the NET_BIND_SERVICE capability.
In this patch, we read the value of the sysctl value via the /proc/sys/
filesystem iff it's present, otherwise we assume the default
unprivileged port range begins at port 1024.
See: tor#40275
When a directory request fails, we flag the relay as non Running so we
don't use it anymore.
This can be problematic with onion services because there are cases
where a tor instance could have a lot of services, ephemeral ones, and
keeps failing to upload descriptors, let say due to a bad network, and
thus flag a lot of nodes as non Running which then in turn can not be
used for circuit building.
This commit makes it that we never flag nodes as non Running on a onion
service directory request (upload or fetch) failure as to keep the
hashring intact and not affect other parts of tor.
Fortunately, the onion service hashring is _not_ selected by looking at
the Running flag but since we do a 3-hop circuit to the HSDir, other
services on the same instance can influence each other by removing nodes
from the consensus for path selection.
This was made apparent with a small network that ran out of nodes to
used due to rapid succession of onion services uploading and failing.
See #40434 for details.
Fixes#40434
Signed-off-by: David Goulet <dgoulet@torproject.org>
Fixes bug 40078.
As reported by hdevalence our batch verification logic can cause an assert
crash.
The assert happens because when the batch verification of ed25519-donna fails,
the code in `ed25519_checksig_batch()` falls back to doing a single
verification for each signature.
The crash occurs because batch verification failed, but then all signatures
individually verified just fine.
That's because batch verification and single verification use a different
equation which means that there are sigs that can pass single verification
but fail batch verification.
Fixing this would require modding ed25519-donna which is not in scope for
this ticket, and will be soon deprecated in favor of arti and
ed25519-dalek, so my branch instead removes batch verification.
David Goulet
Alexander Færøy
Nick Mathewson
George Kadianakis