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| author | Andrew Morgan <1342360+anoadragon453@users.noreply.github.com> | 2020-09-18 14:51:11 +0100 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2020-09-18 14:51:11 +0100 |
| commit | 27c1abc7b876ef3e73c8b418a89b987f86147829 (patch) | |
| tree | 3a22f90364995856582f79c319057e3677b36c16 | |
| parent | 1.19.2 (diff) | |
| download | synapse-27c1abc7b876ef3e73c8b418a89b987f86147829.tar.xz | |
Use _check_sigs_and_hash_and_fetch to validate backfill requests (#8350)
This is a bit of a hack, as `_check_sigs_and_hash_and_fetch` is intended for attempting to pull an event from the database/(re)pull it from the server that originally sent the event if checking the signature of the event fails. During backfill we *know* that we won't have the event in our database, however it is still useful to be able to query the original sending server as the server we're backfilling from may be acting maliciously. The main benefit and reason for this change however is that `_check_sigs_and_hash_and_fetch` will drop an event during backfill if it cannot be successfully validated, whereas the current code will simply fail the backfill request - resulting in the client's /messages request silently being dropped. This is a quick patch to fix backfilling rooms that contain malformed events. A better implementation in planned in future.
| -rw-r--r-- | changelog.d/8350.bugfix | 1 | ||||
| -rw-r--r-- | synapse/federation/federation_client.py | 8 |
2 files changed, 4 insertions, 5 deletions
diff --git a/changelog.d/8350.bugfix b/changelog.d/8350.bugfix new file mode 100644 index 0000000000..0e493c0282 --- /dev/null +++ b/changelog.d/8350.bugfix @@ -0,0 +1 @@ +Partially mitigate bug where newly joined servers couldn't get past events in a room when there is a malformed event. \ No newline at end of file diff --git a/synapse/federation/federation_client.py b/synapse/federation/federation_client.py index a2e8d96ea2..d42930d1b9 100644 --- a/synapse/federation/federation_client.py +++ b/synapse/federation/federation_client.py @@ -217,11 +217,9 @@ class FederationClient(FederationBase): for p in transaction_data["pdus"] ] - # FIXME: We should handle signature failures more gracefully. - pdus[:] = await make_deferred_yieldable( - defer.gatherResults( - self._check_sigs_and_hashes(room_version, pdus), consumeErrors=True, - ).addErrback(unwrapFirstError) + # Check signatures and hash of pdus, removing any from the list that fail checks + pdus[:] = await self._check_sigs_and_hash_and_fetch( + dest, pdus, outlier=True, room_version=room_version ) return pdus |