Keep around the old (buggy) version of the prune_event function so that we can use it to check signatures for events on old servers

synapse/federation/federation_client.py

@@ -16,17 +16,11 @@
 
 from twisted.internet import defer
 
+from .federation_base import FederationBase
 from .units import Edu
 
 from synapse.util.logutils import log_function
 from synapse.events import FrozenEvent
-from synapse.events.utils import prune_event
-
-from syutil.jsonutil import encode_canonical_json
-
-from synapse.crypto.event_signing import check_event_content_hash
-
-from synapse.api.errors import SynapseError
 
 import logging
 
@@ -34,7 +28,7 @@ import logging
 logger = logging.getLogger(__name__)
 
 
-class FederationClient(object):
+class FederationClient(FederationBase):
     @log_function
     def send_pdu(self, pdu, destinations):
         """Informs the replication layer about a new PDU generated within the
@@ -376,89 +370,3 @@ class FederationClient(object):
         event.internal_metadata.outlier = outlier
 
         return event
-
-    @defer.inlineCallbacks
-    def _check_sigs_and_hash_and_fetch(self, origin, pdus, outlier=False):
-        """Takes a list of PDUs and checks the signatures and hashs of each
-        one. If a PDU fails its signature check then we check if we have it in
-        the database and if not then request if from the originating server of
-        that PDU.
-
-        If a PDU fails its content hash check then it is redacted.
-
-        The given list of PDUs are not modified, instead the function returns
-        a new list.
-
-        Args:
-            pdu (list)
-            outlier (bool)
-
-        Returns:
-            Deferred : A list of PDUs that have valid signatures and hashes.
-        """
-        signed_pdus = []
-        for pdu in pdus:
-            try:
-                new_pdu = yield self._check_sigs_and_hash(pdu)
-                signed_pdus.append(new_pdu)
-            except SynapseError:
-                # FIXME: We should handle signature failures more gracefully.
-
-                # Check local db.
-                new_pdu = yield self.store.get_event(
-                    pdu.event_id,
-                    allow_rejected=True
-                )
-                if new_pdu:
-                    signed_pdus.append(new_pdu)
-                    continue
-
-                # Check pdu.origin
-                if pdu.origin != origin:
-                    new_pdu = yield self.get_pdu(
-                        destinations=[pdu.origin],
-                        event_id=pdu.event_id,
-                        outlier=outlier,
-                    )
-
-                    if new_pdu:
-                        signed_pdus.append(new_pdu)
-                        continue
-
-                logger.warn("Failed to find copy of %s with valid signature")
-
-        defer.returnValue(signed_pdus)
-
-    @defer.inlineCallbacks
-    def _check_sigs_and_hash(self, pdu):
-        """Throws a SynapseError if the PDU does not have the correct
-        signatures.
-
-        Returns:
-            FrozenEvent: Either the given event or it redacted if it failed the
-            content hash check.
-        """
-        # Check signatures are correct.
-        redacted_event = prune_event(pdu)
-        redacted_pdu_json = redacted_event.get_pdu_json()
-
-        try:
-            yield self.keyring.verify_json_for_server(
-                pdu.origin, redacted_pdu_json
-            )
-        except SynapseError:
-            logger.warn(
-                "Signature check failed for %s redacted to %s",
-                encode_canonical_json(pdu.get_pdu_json()),
-                encode_canonical_json(redacted_pdu_json),
-            )
-            raise
-
-        if not check_event_content_hash(pdu):
-            logger.warn(
-                "Event content has been tampered, redacting %s, %s",
-                pdu.event_id, encode_canonical_json(pdu.get_dict())
-            )
-            defer.returnValue(redacted_event)
-
-        defer.returnValue(pdu)