diff options
Diffstat (limited to 'synapse/federation/federation_base.py')
| -rw-r--r-- | synapse/federation/federation_base.py | 243 |
1 files changed, 80 insertions, 163 deletions
diff --git a/synapse/federation/federation_base.py b/synapse/federation/federation_base.py index 3fe496dcd3..c066617b92 100644 --- a/synapse/federation/federation_base.py +++ b/synapse/federation/federation_base.py @@ -14,11 +14,6 @@ # limitations under the License. import logging from collections import namedtuple -from typing import Iterable, List - -from twisted.internet import defer -from twisted.internet.defer import Deferred, DeferredList -from twisted.python.failure import Failure from synapse.api.constants import MAX_DEPTH, EventTypes, Membership from synapse.api.errors import Codes, SynapseError @@ -28,11 +23,6 @@ from synapse.crypto.keyring import Keyring from synapse.events import EventBase, make_event_from_dict from synapse.events.utils import prune_event, validate_canonicaljson from synapse.http.servlet import assert_params_in_dict -from synapse.logging.context import ( - PreserveLoggingContext, - current_context, - make_deferred_yieldable, -) from synapse.types import JsonDict, get_domain_from_id logger = logging.getLogger(__name__) @@ -48,112 +38,82 @@ class FederationBase: self.store = hs.get_datastore() self._clock = hs.get_clock() - def _check_sigs_and_hash( + async 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: RoomVersion, pdus: List[EventBase] - ) -> List[Deferred]: - """Checks that each of the received events is correctly signed by the - sending server. + ) -> EventBase: + """Checks that event is correctly signed by the sending server. Args: - room_version: The room version of the PDUs - pdus: the events to be checked + room_version: The room version of the PDU + pdu: the event to be checked Returns: - For each input event, a deferred which: - * returns the original event if the checks pass - * returns a redacted version of the event (if the signature + * the original event if the checks pass + * a redacted version of the event (if the signature matched but the hash did not) - * throws a SynapseError if the signature check failed. - The deferreds run their callbacks in the sentinel - """ - deferreds = _check_sigs_on_pdus(self.keyring, room_version, pdus) - - ctx = current_context() - - @defer.inlineCallbacks - def callback(_, pdu: EventBase): - with PreserveLoggingContext(ctx): - if not check_event_content_hash(pdu): - # let's try to distinguish between failures because the event was - # redacted (which are somewhat expected) vs actual ball-tampering - # incidents. - # - # This is just a heuristic, so we just assume that if the keys are - # about the same between the redacted and received events, then the - # received event was probably a redacted copy (but we then use our - # *actual* redacted copy to be on the safe side.) - redacted_event = prune_event(pdu) - if set(redacted_event.keys()) == set(pdu.keys()) and set( - redacted_event.content.keys() - ) == set(pdu.content.keys()): - logger.info( - "Event %s seems to have been redacted; using our redacted " - "copy", - pdu.event_id, - ) - else: - logger.warning( - "Event %s content has been tampered, redacting", - pdu.event_id, - ) - return redacted_event - - result = yield defer.ensureDeferred( - self.spam_checker.check_event_for_spam(pdu) + * throws a SynapseError if the signature check failed.""" + try: + await _check_sigs_on_pdu(self.keyring, room_version, pdu) + except SynapseError as e: + logger.warning( + "Signature check failed for %s: %s", + pdu.event_id, + e, + ) + raise + + if not check_event_content_hash(pdu): + # let's try to distinguish between failures because the event was + # redacted (which are somewhat expected) vs actual ball-tampering + # incidents. + # + # This is just a heuristic, so we just assume that if the keys are + # about the same between the redacted and received events, then the + # received event was probably a redacted copy (but we then use our + # *actual* redacted copy to be on the safe side.) + redacted_event = prune_event(pdu) + if set(redacted_event.keys()) == set(pdu.keys()) and set( + redacted_event.content.keys() + ) == set(pdu.content.keys()): + logger.info( + "Event %s seems to have been redacted; using our redacted copy", + pdu.event_id, ) - - if result: - logger.warning( - "Event contains spam, redacting %s: %s", - pdu.event_id, - pdu.get_pdu_json(), - ) - return prune_event(pdu) - - return pdu - - def errback(failure: Failure, pdu: EventBase): - failure.trap(SynapseError) - with PreserveLoggingContext(ctx): + else: logger.warning( - "Signature check failed for %s: %s", + "Event %s content has been tampered, redacting", pdu.event_id, - failure.getErrorMessage(), ) - return failure + return redacted_event - for deferred, pdu in zip(deferreds, pdus): - deferred.addCallbacks( - callback, errback, callbackArgs=[pdu], errbackArgs=[pdu] + result = await self.spam_checker.check_event_for_spam(pdu) + + if result: + logger.warning( + "Event contains spam, redacting %s: %s", + pdu.event_id, + pdu.get_pdu_json(), ) + return prune_event(pdu) - return deferreds + return pdu class PduToCheckSig(namedtuple("PduToCheckSig", ["pdu", "sender_domain", "deferreds"])): pass -def _check_sigs_on_pdus( - keyring: Keyring, room_version: RoomVersion, pdus: Iterable[EventBase] -) -> List[Deferred]: +async def _check_sigs_on_pdu( + keyring: Keyring, room_version: RoomVersion, pdu: EventBase +) -> None: """Check that the given events are correctly signed + Raise a SynapseError if the event wasn't correctly signed. + Args: keyring: keyring object to do the checks room_version: the room version of the PDUs pdus: the events to be checked - - Returns: - A Deferred for each event in pdus, which will either succeed if - the signatures are valid, or fail (with a SynapseError) if not. """ # we want to check that the event is signed by: @@ -177,90 +137,47 @@ def _check_sigs_on_pdus( # let's start by getting the domain for each pdu, and flattening the event back # to JSON. - pdus_to_check = [ - PduToCheckSig( - pdu=p, - sender_domain=get_domain_from_id(p.sender), - deferreds=[], - ) - for p in pdus - ] - # 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)] - - more_deferreds = keyring.verify_events_for_server( - [ - ( - p.sender_domain, - p.pdu, - p.pdu.origin_server_ts if room_version.enforce_key_validity else 0, + if not _is_invite_via_3pid(pdu): + try: + await keyring.verify_event_for_server( + get_domain_from_id(pdu.sender), + pdu, + pdu.origin_server_ts if room_version.enforce_key_validity else 0, ) - for p in pdus_to_check_sender - ] - ) - - def sender_err(e, pdu_to_check): - errmsg = "event id %s: unable to verify signature for sender %s: %s" % ( - pdu_to_check.pdu.event_id, - pdu_to_check.sender_domain, - e.getErrorMessage(), - ) - raise SynapseError(403, errmsg, Codes.FORBIDDEN) - - for p, d in zip(pdus_to_check_sender, more_deferreds): - d.addErrback(sender_err, p) - p.deferreds.append(d) + except Exception as e: + errmsg = "event id %s: unable to verify signature for sender %s: %s" % ( + pdu.event_id, + get_domain_from_id(pdu.sender), + e, + ) + raise SynapseError(403, errmsg, Codes.FORBIDDEN) # now let's look for events where the sender's domain is different to the # 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 room_version.event_format == EventFormatVersions.V1: - pdus_to_check_event_id = [ - p - for p in pdus_to_check - if p.sender_domain != get_domain_from_id(p.pdu.event_id) - ] - - more_deferreds = keyring.verify_events_for_server( - [ - ( - get_domain_from_id(p.pdu.event_id), - p.pdu, - p.pdu.origin_server_ts if room_version.enforce_key_validity else 0, - ) - for p in pdus_to_check_event_id - ] - ) - - def event_err(e, pdu_to_check): + if room_version.event_format == EventFormatVersions.V1 and get_domain_from_id( + pdu.event_id + ) != get_domain_from_id(pdu.sender): + try: + await keyring.verify_event_for_server( + get_domain_from_id(pdu.event_id), + pdu, + pdu.origin_server_ts if room_version.enforce_key_validity else 0, + ) + except Exception as e: errmsg = ( - "event id %s: unable to verify signature for event id domain: %s" - % (pdu_to_check.pdu.event_id, e.getErrorMessage()) + "event id %s: unable to verify signature for event id domain %s: %s" + % ( + pdu.event_id, + get_domain_from_id(pdu.event_id), + e, + ) ) raise SynapseError(403, errmsg, Codes.FORBIDDEN) - for p, d in zip(pdus_to_check_event_id, more_deferreds): - d.addErrback(event_err, p) - p.deferreds.append(d) - - # replace lists of deferreds with single Deferreds - return [_flatten_deferred_list(p.deferreds) for p in pdus_to_check] - - -def _flatten_deferred_list(deferreds: List[Deferred]) -> Deferred: - """Given a list of deferreds, either return the single deferred, - combine into a DeferredList, or return an already resolved deferred. - """ - if len(deferreds) > 1: - return DeferredList(deferreds, fireOnOneErrback=True, consumeErrors=True) - elif len(deferreds) == 1: - return deferreds[0] - else: - return defer.succeed(None) - def _is_invite_via_3pid(event: EventBase) -> bool: return ( |