Merge pull request #47 from matrix-org/signature_failures

Federation fixes.

1 files changed, 31 insertions, 68 deletions

diff --git a/synapse/federation/federation_client.py b/synapse/federation/federation_client.py
index e1539bd0e0..5fac629709 100644
--- a/synapse/federation/federation_client.py
+++ b/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
@@ -224,17 +218,17 @@ class FederationClient(object):
             for p in result.get("auth_chain", [])
         ]
 
-        for i, pdu in enumerate(pdus):
-            pdus[i] = yield self._check_sigs_and_hash(pdu)
-
-            # FIXME: We should handle signature failures more gracefully.
+        signed_pdus = yield self._check_sigs_and_hash_and_fetch(
+            destination, pdus, outlier=True
+        )
 
-        for i, pdu in enumerate(auth_chain):
-            auth_chain[i] = yield self._check_sigs_and_hash(pdu)
+        signed_auth = yield self._check_sigs_and_hash_and_fetch(
+            destination, auth_chain, outlier=True
+        )
 
-            # FIXME: We should handle signature failures more gracefully.
+        signed_auth.sort(key=lambda e: e.depth)
 
-        defer.returnValue((pdus, auth_chain))
+        defer.returnValue((signed_pdus, signed_auth))
 
     @defer.inlineCallbacks
     @log_function
@@ -248,14 +242,13 @@ class FederationClient(object):
             for p in res["auth_chain"]
         ]
 
-        for i, pdu in enumerate(auth_chain):
-            auth_chain[i] = yield self._check_sigs_and_hash(pdu)
-
-            # FIXME: We should handle signature failures more gracefully.
+        signed_auth = yield self._check_sigs_and_hash_and_fetch(
+            destination, auth_chain, outlier=True
+        )
 
-        auth_chain.sort(key=lambda e: e.depth)
+        signed_auth.sort(key=lambda e: e.depth)
 
-        defer.returnValue(auth_chain)
+        defer.returnValue(signed_auth)
 
     @defer.inlineCallbacks
     def make_join(self, destination, room_id, user_id):
@@ -291,21 +284,19 @@ class FederationClient(object):
             for p in content.get("auth_chain", [])
         ]
 
-        for i, pdu in enumerate(state):
-            state[i] = yield self._check_sigs_and_hash(pdu)
-
-            # FIXME: We should handle signature failures more gracefully.
-
-        for i, pdu in enumerate(auth_chain):
-            auth_chain[i] = yield self._check_sigs_and_hash(pdu)
+        signed_state = yield self._check_sigs_and_hash_and_fetch(
+            destination, state, outlier=True
+        )
 
-            # FIXME: We should handle signature failures more gracefully.
+        signed_auth = yield self._check_sigs_and_hash_and_fetch(
+            destination, auth_chain, outlier=True
+        )
 
         auth_chain.sort(key=lambda e: e.depth)
 
         defer.returnValue({
-            "state": state,
-            "auth_chain": auth_chain,
+            "state": signed_state,
+            "auth_chain": signed_auth,
         })
 
     @defer.inlineCallbacks
@@ -353,12 +344,18 @@ class FederationClient(object):
         )
 
         auth_chain = [
-            (yield self._check_sigs_and_hash(self.event_from_pdu_json(e)))
+            self.event_from_pdu_json(e)
             for e in content["auth_chain"]
         ]
 
+        signed_auth = yield self._check_sigs_and_hash_and_fetch(
+            destination, auth_chain, outlier=True
+        )
+
+        signed_auth.sort(key=lambda e: e.depth)
+
         ret = {
-            "auth_chain": auth_chain,
+            "auth_chain": signed_auth,
             "rejects": content.get("rejects", []),
             "missing": content.get("missing", []),
         }
@@ -373,37 +370,3 @@ class FederationClient(object):
         event.internal_metadata.outlier = outlier
 
         return event
-
-    @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)