Weakness in auth chain indexing allows DoS from remote room members
through disk fill and high CPU usage.
A remote Matrix user with malicious intent, sharing a room with Synapse
instances before 1.104.1, can dispatch specially crafted events to
exploit a weakness in how the auth chain cover index is calculated. This
can induce high CPU consumption and accumulate excessive data in the
database of such instances, resulting in a denial of service.
Servers in private federations, or those that do not federate, are not
affected.
During the migration the automated script to update the copyright
headers accidentally got rid of some of the existing copyright lines.
Reinstate them.
This reverts two commits:
0bb8e418a4
"Fix postgres schema after dropping old tables (#16730)"
and
51e4e35653
"Add a Postgres `REPLICA IDENTITY` to tables that do not have an implicit one. This should allow use of Postgres logical replication. (take 2, now with no added deadlocks!) (#16658)"
and also amends the changelog.
* Add `ALTER TABLE ... REPLICA IDENTITY ...` for individual tables
We can't combine them into one file as it makes it likely to hit a deadlock
if Synapse is running, as it only takes one other transaction to access two
tables in a different order to the schema delta.
* Add notes
* Newsfile
Signed-off-by: Olivier Wilkinson (reivilibre) <oliverw@matrix.org>
* Re-introduce REPLICA IDENTITY test
---------
Signed-off-by: Olivier Wilkinson (reivilibre) <oliverw@matrix.org>
* Fix the CI query that did not detect all cases of missing primary keys
* Add more missing REPLICA IDENTITY entries
* Newsfile
Signed-off-by: Olivier Wilkinson (reivilibre) <oliverw@matrix.org>
---------
Signed-off-by: Olivier Wilkinson (reivilibre) <oliverw@matrix.org>
* Add Postgres replica identities to tables that don't have an implicit one
Fixes#16224
* Newsfile
Signed-off-by: Olivier Wilkinson (reivilibre) <oliverw@matrix.org>
* Move the delta to version 83 as we missed the boat for 82
* Add a test that all tables have a REPLICA IDENTITY
* Extend the test to include when indices are deleted
* isort
* black
* Fully qualify `oid` as it is a 'hidden attribute' in Postgres 11
* Update tests/storage/test_database.py
Co-authored-by: Patrick Cloke <clokep@users.noreply.github.com>
* Add missed tables
---------
Signed-off-by: Olivier Wilkinson (reivilibre) <oliverw@matrix.org>
Co-authored-by: Patrick Cloke <clokep@users.noreply.github.com>
This splits thinsg into two queries, but most of the time we won't have
new event backwards extremities so this shouldn't actually add an extra
RTT for the majority of cases.
Note this removes the check for events with no prev events, but that was
part of MSC2716 work that has since been removed.
For now this maintains compatible with old Synapses by falling back
to using transaction semantics on a per-access token. A future version
of Synapse will drop support for this.
There appears to be a race where you can end up with entries in
`event_push_summary` with both a `NULL` and `main` thread ID.
Fixes#15736
Introduced in #15597
