From 941f59101b51e9225dbdc38b22110a01de194242 Mon Sep 17 00:00:00 2001 From: Erik Johnston Date: Mon, 2 Feb 2015 16:56:01 +0000 Subject: [PATCH] Don't fail an entire request if one of the returned events fails a signature check. If an event does fail a signature check, look in the local database and request it from the originator. --- synapse/federation/federation_client.py | 107 ++++++++++++++++++------ synapse/storage/__init__.py | 21 +++-- 2 files changed, 94 insertions(+), 34 deletions(-) diff --git a/synapse/federation/federation_client.py b/synapse/federation/federation_client.py index e1539bd0e..b809e935a 100644 --- a/synapse/federation/federation_client.py +++ b/synapse/federation/federation_client.py @@ -224,17 +224,17 @@ 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) + signed_pdus = yield self._check_sigs_and_hash_and_fetch( + pdus, outlier=True + ) - # FIXME: We should handle signature failures more gracefully. + signed_auth = yield self._check_sigs_and_hash_and_fetch( + auth_chain, outlier=True + ) - for i, pdu in enumerate(auth_chain): - auth_chain[i] = yield self._check_sigs_and_hash(pdu) + signed_auth.sort(key=lambda e: e.depth) - # FIXME: We should handle signature failures more gracefully. - - defer.returnValue((pdus, auth_chain)) + defer.returnValue((signed_pdus, signed_auth)) @defer.inlineCallbacks @log_function @@ -248,14 +248,13 @@ 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) + signed_auth = yield self._check_sigs_and_hash_and_fetch( + auth_chain, outlier=True + ) - # FIXME: We should handle signature failures more gracefully. + signed_auth.sort(key=lambda e: e.depth) - auth_chain.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 +290,19 @@ 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) + signed_state = yield self._check_sigs_and_hash_and_fetch( + state, outlier=True + ) - # 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) - - # FIXME: We should handle signature failures more gracefully. + signed_auth = yield self._check_sigs_and_hash_and_fetch( + 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 +350,18 @@ 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( + 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", []), } @@ -374,6 +377,58 @@ class FederationClient(object): return event + @defer.inlineCallbacks + def _check_sigs_and_hash_and_fetch(self, 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 + 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 diff --git a/synapse/storage/__init__.py b/synapse/storage/__init__.py index 7c54b1b9d..b4a7a3f06 100644 --- a/synapse/storage/__init__.py +++ b/synapse/storage/__init__.py @@ -128,16 +128,21 @@ class DataStore(RoomMemberStore, RoomStore, pass @defer.inlineCallbacks - def get_event(self, event_id, allow_none=False): - events = yield self._get_events([event_id]) + def get_event(self, event_id, check_redacted=True, + get_prev_content=False, allow_rejected=False, + allow_none=False): + event = yield self.runInteraction( + "get_event", self._get_event_txn, + event_id, + check_redacted=check_redacted, + get_prev_content=get_prev_content, + allow_rejected=allow_rejected, + ) - if not events: - if allow_none: - defer.returnValue(None) - else: - raise RuntimeError("Could not find event %s" % (event_id,)) + if not event and not allow_none: + raise RuntimeError("Could not find event %s" % (event_id,)) - defer.returnValue(events[0]) + defer.returnValue(event) @log_function def _persist_event_txn(self, txn, event, context, backfilled,