123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158 |
- # -*- coding: utf-8 -*-
- # Copyright 2015, 2016 OpenMarket Ltd
- #
- # Licensed under the Apache License, Version 2.0 (the "License");
- # you may not use this file except in compliance with the License.
- # You may obtain a copy of the License at
- #
- # http://www.apache.org/licenses/LICENSE-2.0
- #
- # Unless required by applicable law or agreed to in writing, software
- # distributed under the License is distributed on an "AS IS" BASIS,
- # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- # See the License for the specific language governing permissions and
- # limitations under the License.
- from twisted.internet import defer
- from synapse.events.utils import prune_event
- from synapse.crypto.event_signing import check_event_content_hash
- from synapse.api.errors import SynapseError
- from synapse.util import unwrapFirstError
- import logging
- logger = logging.getLogger(__name__)
- class FederationBase(object):
- @defer.inlineCallbacks
- def _check_sigs_and_hash_and_fetch(self, origin, pdus, outlier=False,
- include_none=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.
- """
- deferreds = self._check_sigs_and_hashes(pdus)
- def callback(pdu):
- return pdu
- def errback(failure, pdu):
- failure.trap(SynapseError)
- return None
- def try_local_db(res, pdu):
- if not res:
- # Check local db.
- return self.store.get_event(
- pdu.event_id,
- allow_rejected=True,
- allow_none=True,
- )
- return res
- def try_remote(res, pdu):
- if not res and pdu.origin != origin:
- return self.get_pdu(
- destinations=[pdu.origin],
- event_id=pdu.event_id,
- outlier=outlier,
- timeout=10000,
- ).addErrback(lambda e: None)
- return res
- def warn(res, pdu):
- if not res:
- logger.warn(
- "Failed to find copy of %s with valid signature",
- pdu.event_id,
- )
- return res
- for pdu, deferred in zip(pdus, deferreds):
- deferred.addCallbacks(
- callback, errback, errbackArgs=[pdu]
- ).addCallback(
- try_local_db, pdu
- ).addCallback(
- try_remote, pdu
- ).addCallback(
- warn, pdu
- )
- valid_pdus = yield defer.gatherResults(
- deferreds,
- consumeErrors=True
- ).addErrback(unwrapFirstError)
- if include_none:
- defer.returnValue(valid_pdus)
- else:
- defer.returnValue([p for p in valid_pdus if p])
- def _check_sigs_and_hash(self, pdu):
- return self._check_sigs_and_hashes([pdu])[0]
- def _check_sigs_and_hashes(self, pdus):
- """Throws a SynapseError if a PDU does not have the correct
- signatures.
- Returns:
- FrozenEvent: Either the given event or it redacted if it failed the
- content hash check.
- """
- redacted_pdus = [
- prune_event(pdu)
- for pdu in pdus
- ]
- deferreds = self.keyring.verify_json_objects_for_server([
- (p.origin, p.get_pdu_json())
- for p in redacted_pdus
- ])
- def callback(_, pdu, redacted):
- if not check_event_content_hash(pdu):
- logger.warn(
- "Event content has been tampered, redacting %s: %s",
- pdu.event_id, pdu.get_pdu_json()
- )
- return redacted
- return pdu
- def errback(failure, pdu):
- failure.trap(SynapseError)
- logger.warn(
- "Signature check failed for %s",
- pdu.event_id,
- )
- return failure
- for deferred, pdu, redacted in zip(deferreds, pdus, redacted_pdus):
- deferred.addCallbacks(
- callback, errback,
- callbackArgs=[pdu, redacted],
- errbackArgs=[pdu],
- )
- return deferreds
|