diff options
Diffstat (limited to 'synapse/federation')
| -rw-r--r-- | synapse/federation/federation_base.py | 25 | ||||
| -rw-r--r-- | synapse/federation/federation_client.py | 50 |
2 files changed, 62 insertions, 13 deletions
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) diff --git a/synapse/federation/federation_client.py b/synapse/federation/federation_client.py index 464672a3da..4dca711cd2 100644 --- a/synapse/federation/federation_client.py +++ b/synapse/federation/federation_client.py @@ -278,7 +278,7 @@ class FederationClient(FederationBase): pdus = [event_from_pdu_json(p, room_version) for p in transaction_data_pdus] # Check signatures and hash of pdus, removing any from the list that fail checks - pdus[:] = await self._check_sigs_and_hash_and_fetch( + pdus[:] = await self._check_sigs_and_hash_for_pulled_events_and_fetch( dest, pdus, room_version=room_version ) @@ -328,7 +328,17 @@ class FederationClient(FederationBase): # Check signatures are correct. try: - signed_pdu = await self._check_sigs_and_hash(room_version, pdu) + + async def _record_failure_callback( + event: EventBase, cause: str + ) -> None: + await self.store.record_event_failed_pull_attempt( + event.room_id, event.event_id, cause + ) + + signed_pdu = await self._check_sigs_and_hash( + room_version, pdu, _record_failure_callback + ) except InvalidEventSignatureError as e: errmsg = f"event id {pdu.event_id}: {e}" logger.warning("%s", errmsg) @@ -547,24 +557,28 @@ class FederationClient(FederationBase): len(auth_event_map), ) - valid_auth_events = await self._check_sigs_and_hash_and_fetch( + valid_auth_events = await self._check_sigs_and_hash_for_pulled_events_and_fetch( destination, auth_event_map.values(), room_version ) - valid_state_events = await self._check_sigs_and_hash_and_fetch( - destination, state_event_map.values(), room_version + valid_state_events = ( + await self._check_sigs_and_hash_for_pulled_events_and_fetch( + destination, state_event_map.values(), room_version + ) ) return valid_state_events, valid_auth_events @trace - async def _check_sigs_and_hash_and_fetch( + async def _check_sigs_and_hash_for_pulled_events_and_fetch( self, origin: str, pdus: Collection[EventBase], room_version: RoomVersion, ) -> List[EventBase]: - """Checks the signatures and hashes of a list of events. + """ + Checks the signatures and hashes of a list of pulled events we got from + federation and records any signature failures as failed pull attempts. If a PDU fails its signature check then we check if we have it in the database, and if not then request it from the sender's server (if that @@ -597,11 +611,17 @@ class FederationClient(FederationBase): valid_pdus: List[EventBase] = [] + async def _record_failure_callback(event: EventBase, cause: str) -> None: + await self.store.record_event_failed_pull_attempt( + event.room_id, event.event_id, cause + ) + async def _execute(pdu: EventBase) -> None: valid_pdu = await self._check_sigs_and_hash_and_fetch_one( pdu=pdu, origin=origin, room_version=room_version, + record_failure_callback=_record_failure_callback, ) if valid_pdu: @@ -618,6 +638,9 @@ class FederationClient(FederationBase): pdu: EventBase, origin: str, room_version: RoomVersion, + record_failure_callback: Optional[ + Callable[[EventBase, str], Awaitable[None]] + ] = None, ) -> Optional[EventBase]: """Takes a PDU and checks its signatures and hashes. @@ -634,6 +657,11 @@ class FederationClient(FederationBase): origin pdu room_version + 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 PDU (possibly redacted) if it has valid signatures and hashes. @@ -641,7 +669,9 @@ class FederationClient(FederationBase): """ try: - return await self._check_sigs_and_hash(room_version, pdu) + return await self._check_sigs_and_hash( + room_version, pdu, record_failure_callback + ) except InvalidEventSignatureError as e: logger.warning( "Signature on retrieved event %s was invalid (%s). " @@ -694,7 +724,7 @@ class FederationClient(FederationBase): auth_chain = [event_from_pdu_json(p, room_version) for p in res["auth_chain"]] - signed_auth = await self._check_sigs_and_hash_and_fetch( + signed_auth = await self._check_sigs_and_hash_for_pulled_events_and_fetch( destination, auth_chain, room_version=room_version ) @@ -1401,7 +1431,7 @@ class FederationClient(FederationBase): event_from_pdu_json(e, room_version) for e in content.get("events", []) ] - signed_events = await self._check_sigs_and_hash_and_fetch( + signed_events = await self._check_sigs_and_hash_for_pulled_events_and_fetch( destination, events, room_version=room_version ) except HttpResponseException as e: |