diff --git a/synapse/federation/federation_base.py b/synapse/federation/federation_base.py
index abe2c1971a..6bd4742140 100644
--- a/synapse/federation/federation_base.py
+++ b/synapse/federation/federation_base.py
@@ -13,7 +13,7 @@
# See the License for the specific language governing permissions and
# limitations under the License.
import logging
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Awaitable, Callable, Optional
from synapse.api.constants import MAX_DEPTH, EventContentFields, EventTypes, Membership
from synapse.api.errors import Codes, SynapseError
@@ -58,7 +58,12 @@ class FederationBase:
@trace
async def _check_sigs_and_hash(
- self, room_version: RoomVersion, pdu: EventBase
+ self,
+ room_version: RoomVersion,
+ pdu: EventBase,
+ record_failure_callback: Optional[
+ Callable[[EventBase, str], Awaitable[None]]
+ ] = None,
) -> EventBase:
"""Checks that event is correctly signed by the sending server.
@@ -70,6 +75,11 @@ class FederationBase:
Args:
room_version: The room version of the PDU
pdu: the event to be checked
+ record_failure_callback: A callback to run whenever the given event
+ fails signature or hash checks. This includes exceptions
+ that would be normally be thrown/raised but also things like
+ checking for event tampering where we just return the redacted
+ event.
Returns:
* the original event if the checks pass
@@ -80,7 +90,12 @@ class FederationBase:
InvalidEventSignatureError if the signature check failed. Nothing
will be logged in this case.
"""
- await _check_sigs_on_pdu(self.keyring, room_version, pdu)
+ try:
+ await _check_sigs_on_pdu(self.keyring, room_version, pdu)
+ except InvalidEventSignatureError as exc:
+ if record_failure_callback:
+ await record_failure_callback(pdu, str(exc))
+ raise exc
if not check_event_content_hash(pdu):
# let's try to distinguish between failures because the event was
@@ -116,6 +131,10 @@ class FederationBase:
"event_id": pdu.event_id,
}
)
+ if record_failure_callback:
+ await record_failure_callback(
+ pdu, "Event content has been tampered with"
+ )
return redacted_event
spam_check = await self.spam_checker.check_event_for_spam(pdu)
|
