Fix a bug in the federation API which could cause occasional "Failed to get PDU" errors (#7089).

4 files changed, 22 insertions, 30 deletions

diff --git a/changelog.d/7089.bugfix b/changelog.d/7089.bugfix
new file mode 100644
index 0000000000..f1f440f23a
--- /dev/null
+++ b/changelog.d/7089.bugfix
@@ -0,0 +1 @@
+Fix a bug in the federation API which could cause occasional "Failed to get PDU" errors.
diff --git a/synapse/federation/federation_base.py b/synapse/federation/federation_base.py
index 5c991e5412..b0b0eba41e 100644
--- a/synapse/federation/federation_base.py
+++ b/synapse/federation/federation_base.py
@@ -25,11 +25,7 @@ from twisted.python.failure import Failure
 
 from synapse.api.constants import MAX_DEPTH, EventTypes, Membership
 from synapse.api.errors import Codes, SynapseError
-from synapse.api.room_versions import (
-    KNOWN_ROOM_VERSIONS,
-    EventFormatVersions,
-    RoomVersion,
-)
+from synapse.api.room_versions import EventFormatVersions, RoomVersion
 from synapse.crypto.event_signing import check_event_content_hash
 from synapse.crypto.keyring import Keyring
 from synapse.events import EventBase, make_event_from_dict
@@ -55,13 +51,15 @@ class FederationBase(object):
         self.store = hs.get_datastore()
         self._clock = hs.get_clock()
 
-    def _check_sigs_and_hash(self, room_version: str, pdu: EventBase) -> Deferred:
+    def _check_sigs_and_hash(
+        self, room_version: RoomVersion, pdu: EventBase
+    ) -> Deferred:
         return make_deferred_yieldable(
             self._check_sigs_and_hashes(room_version, [pdu])[0]
         )
 
     def _check_sigs_and_hashes(
-        self, room_version: str, pdus: List[EventBase]
+        self, room_version: RoomVersion, pdus: List[EventBase]
     ) -> List[Deferred]:
         """Checks that each of the received events is correctly signed by the
         sending server.
@@ -146,7 +144,7 @@ class PduToCheckSig(
 
 
 def _check_sigs_on_pdus(
-    keyring: Keyring, room_version: str, pdus: Iterable[EventBase]
+    keyring: Keyring, room_version: RoomVersion, pdus: Iterable[EventBase]
 ) -> List[Deferred]:
     """Check that the given events are correctly signed
 
@@ -191,10 +189,6 @@ def _check_sigs_on_pdus(
         for p in pdus
     ]
 
-    v = KNOWN_ROOM_VERSIONS.get(room_version)
-    if not v:
-        raise RuntimeError("Unrecognized room version %s" % (room_version,))
-
     # First we check that the sender event is signed by the sender's domain
     # (except if its a 3pid invite, in which case it may be sent by any server)
     pdus_to_check_sender = [p for p in pdus_to_check if not _is_invite_via_3pid(p.pdu)]
@@ -204,7 +198,7 @@ def _check_sigs_on_pdus(
             (
                 p.sender_domain,
                 p.redacted_pdu_json,
-                p.pdu.origin_server_ts if v.enforce_key_validity else 0,
+                p.pdu.origin_server_ts if room_version.enforce_key_validity else 0,
                 p.pdu.event_id,
             )
             for p in pdus_to_check_sender
@@ -227,7 +221,7 @@ def _check_sigs_on_pdus(
     # event id's domain (normally only the case for joins/leaves), and add additional
     # checks. Only do this if the room version has a concept of event ID domain
     # (ie, the room version uses old-style non-hash event IDs).
-    if v.event_format == EventFormatVersions.V1:
+    if room_version.event_format == EventFormatVersions.V1:
         pdus_to_check_event_id = [
             p
             for p in pdus_to_check
@@ -239,7 +233,7 @@ def _check_sigs_on_pdus(
                 (
                     get_domain_from_id(p.pdu.event_id),
                     p.redacted_pdu_json,
-                    p.pdu.origin_server_ts if v.enforce_key_validity else 0,
+                    p.pdu.origin_server_ts if room_version.enforce_key_validity else 0,
                     p.pdu.event_id,
                 )
                 for p in pdus_to_check_event_id
diff --git a/synapse/federation/federation_client.py b/synapse/federation/federation_client.py
index 8c6b839478..a0071fec94 100644
--- a/synapse/federation/federation_client.py
+++ b/synapse/federation/federation_client.py
@@ -220,8 +220,7 @@ class FederationClient(FederationBase):
         # FIXME: We should handle signature failures more gracefully.
         pdus[:] = await make_deferred_yieldable(
             defer.gatherResults(
-                self._check_sigs_and_hashes(room_version.identifier, pdus),
-                consumeErrors=True,
+                self._check_sigs_and_hashes(room_version, pdus), consumeErrors=True,
             ).addErrback(unwrapFirstError)
         )
 
@@ -291,9 +290,7 @@ class FederationClient(FederationBase):
                     pdu = pdu_list[0]
 
                     # Check signatures are correct.
-                    signed_pdu = await self._check_sigs_and_hash(
-                        room_version.identifier, pdu
-                    )
+                    signed_pdu = await self._check_sigs_and_hash(room_version, pdu)
 
                     break
 
@@ -350,7 +347,7 @@ class FederationClient(FederationBase):
         self,
         origin: str,
         pdus: List[EventBase],
-        room_version: str,
+        room_version: RoomVersion,
         outlier: bool = False,
         include_none: bool = False,
     ) -> List[EventBase]:
@@ -396,7 +393,7 @@ class FederationClient(FederationBase):
                         self.get_pdu(
                             destinations=[pdu.origin],
                             event_id=pdu.event_id,
-                            room_version=room_version,  # type: ignore
+                            room_version=room_version,
                             outlier=outlier,
                             timeout=10000,
                         )
@@ -434,7 +431,7 @@ class FederationClient(FederationBase):
         ]
 
         signed_auth = await self._check_sigs_and_hash_and_fetch(
-            destination, auth_chain, outlier=True, room_version=room_version.identifier
+            destination, auth_chain, outlier=True, room_version=room_version
         )
 
         signed_auth.sort(key=lambda e: e.depth)
@@ -661,7 +658,7 @@ class FederationClient(FederationBase):
                 destination,
                 list(pdus.values()),
                 outlier=True,
-                room_version=room_version.identifier,
+                room_version=room_version,
             )
 
             valid_pdus_map = {p.event_id: p for p in valid_pdus}
@@ -756,7 +753,7 @@ class FederationClient(FederationBase):
         pdu = event_from_pdu_json(pdu_dict, room_version)
 
         # Check signatures are correct.
-        pdu = await self._check_sigs_and_hash(room_version.identifier, pdu)
+        pdu = await self._check_sigs_and_hash(room_version, pdu)
 
         # FIXME: We should handle signature failures more gracefully.
 
@@ -948,7 +945,7 @@ class FederationClient(FederationBase):
             ]
 
             signed_events = await self._check_sigs_and_hash_and_fetch(
-                destination, events, outlier=False, room_version=room_version.identifier
+                destination, events, outlier=False, room_version=room_version
             )
         except HttpResponseException as e:
             if not e.code == 400:
diff --git a/synapse/federation/federation_server.py b/synapse/federation/federation_server.py
index 275b9c99d7..89d521bc31 100644
--- a/synapse/federation/federation_server.py
+++ b/synapse/federation/federation_server.py
@@ -409,7 +409,7 @@ class FederationServer(FederationBase):
         pdu = event_from_pdu_json(content, room_version)
         origin_host, _ = parse_server_name(origin)
         await self.check_server_matches_acl(origin_host, pdu.room_id)
-        pdu = await self._check_sigs_and_hash(room_version.identifier, pdu)
+        pdu = await self._check_sigs_and_hash(room_version, pdu)
         ret_pdu = await self.handler.on_invite_request(origin, pdu, room_version)
         time_now = self._clock.time_msec()
         return {"event": ret_pdu.get_pdu_json(time_now)}
@@ -425,7 +425,7 @@ class FederationServer(FederationBase):
 
         logger.debug("on_send_join_request: pdu sigs: %s", pdu.signatures)
 
-        pdu = await self._check_sigs_and_hash(room_version.identifier, pdu)
+        pdu = await self._check_sigs_and_hash(room_version, pdu)
 
         res_pdus = await self.handler.on_send_join_request(origin, pdu)
         time_now = self._clock.time_msec()
@@ -455,7 +455,7 @@ class FederationServer(FederationBase):
 
         logger.debug("on_send_leave_request: pdu sigs: %s", pdu.signatures)
 
-        pdu = await self._check_sigs_and_hash(room_version.identifier, pdu)
+        pdu = await self._check_sigs_and_hash(room_version, pdu)
 
         await self.handler.on_send_leave_request(origin, pdu)
         return {}
@@ -611,7 +611,7 @@ class FederationServer(FederationBase):
                 logger.info("Accepting join PDU %s from %s", pdu.event_id, origin)
 
         # We've already checked that we know the room version by this point
-        room_version = await self.store.get_room_version_id(pdu.room_id)
+        room_version = await self.store.get_room_version(pdu.room_id)
 
         # Check signature.
         try: