anonymousland-synapse/synapse/api
Eric Eastwood 40bb37eb27
Stop getting missing prev_events after we already know their signature is invalid (#13816)
While https://github.com/matrix-org/synapse/pull/13635 stops us from doing the slow thing after we've already done it once, this PR stops us from doing one of the slow things in the first place.

Related to
 - https://github.com/matrix-org/synapse/issues/13622
    - https://github.com/matrix-org/synapse/pull/13635
 - https://github.com/matrix-org/synapse/issues/13676

Part of https://github.com/matrix-org/synapse/issues/13356

Follow-up to https://github.com/matrix-org/synapse/pull/13815 which tracks event signature failures.

With this PR, we avoid the call to the costly `_get_state_ids_after_missing_prev_event` because the signature failure will count as an attempt before and we filter events based on the backoff before calling `_get_state_ids_after_missing_prev_event` now.

For example, this will save us 156s out of the 185s total that this `matrix.org` `/messages` request. If you want to see the full Jaeger trace of this, you can drag and drop this `trace.json` into your own Jaeger, https://gist.github.com/MadLittleMods/4b12d0d0afe88c2f65ffcc907306b761

To explain this exact scenario around `/messages` -> backfill, we call `/backfill` and first check the signatures of the 100 events. We see bad signature for `$luA4l7QHhf_jadH3mI-AyFqho0U2Q-IXXUbGSMq6h6M` and `$zuOn2Rd2vsC7SUia3Hp3r6JSkSFKcc5j3QTTqW_0jDw` (both member events). Then we process the 98 events remaining that have valid signatures but one of the events references `$luA4l7QHhf_jadH3mI-AyFqho0U2Q-IXXUbGSMq6h6M` as a `prev_event`. So we have to do the whole `_get_state_ids_after_missing_prev_event` rigmarole which pulls in those same events which fail again because the signatures are still invalid.

 - `backfill`
    - `outgoing-federation-request` `/backfill`
    - `_check_sigs_and_hash_and_fetch`
       - `_check_sigs_and_hash_and_fetch_one` for each event received over backfill
          -  `$luA4l7QHhf_jadH3mI-AyFqho0U2Q-IXXUbGSMq6h6M` fails with `Signature on retrieved event was invalid.`: `unable to verify signature for sender domain xxx: 401: Failed to find any key to satisfy: _FetchKeyRequest(...)`
          -  `$zuOn2Rd2vsC7SUia3Hp3r6JSkSFKcc5j3QTTqW_0jDw` fails with `Signature on retrieved event was invalid.`: `unable to verify signature for sender domain xxx: 401: Failed to find any key to satisfy: _FetchKeyRequest(...)`
   - `_process_pulled_events`
      - `_process_pulled_event` for each validated event
         -  Event `$Q0iMdqtz3IJYfZQU2Xk2WjB5NDF8Gg8cFSYYyKQgKJ0` references `$luA4l7QHhf_jadH3mI-AyFqho0U2Q-IXXUbGSMq6h6M` as a `prev_event` which is missing so we try to get it
            - `_get_state_ids_after_missing_prev_event`
               - `outgoing-federation-request` `/state_ids`
               -  `get_pdu` for `$luA4l7QHhf_jadH3mI-AyFqho0U2Q-IXXUbGSMq6h6M` which fails the signature check again
               -  `get_pdu` for `$zuOn2Rd2vsC7SUia3Hp3r6JSkSFKcc5j3QTTqW_0jDw` which fails the signature check
2022-10-15 00:36:49 -05:00
..
__init__.py Remove redundant "coding: utf-8" lines (#9786) 2021-04-14 15:34:27 +01:00
auth_blocking.py Remove HomeServer.get_datastore() (#12031) 2022-02-23 11:04:02 +00:00
auth.py Remove unused method in synapse.api.auth.Auth. (#13795) 2022-09-14 10:33:54 -04:00
constants.py Track notification counts per thread (implement MSC3773). (#13776) 2022-10-04 09:47:04 -04:00
errors.py Stop getting missing prev_events after we already know their signature is invalid (#13816) 2022-10-15 00:36:49 -05:00
filtering.py Use stable identifiers for MSC3771 & MSC3773. (#14050) 2022-10-07 09:26:40 -04:00
presence.py Add missing type hints to synapse.api. (#11109) 2021-10-18 15:01:10 -04:00
ratelimiting.py Rename RateLimitConfig to RatelimitSettings (#13442) 2022-08-03 10:40:20 +01:00
room_versions.py Rename the EventFormatVersions enum values so that they line up with room version numbers. (#13706) 2022-09-07 11:08:20 +01:00
urls.py Remove support for the webclient listener. (#11895) 2022-02-03 18:36:49 +00:00