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Only check event ID domain for signatures for V1 events

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In future version events won't have an event ID, so we won't be able to
do this check.
This commit is contained in:
Erik Johnston 2019-01-29 17:21:48 +00:00
parent 8e3d34e3c5
commit 840068bd78
3 changed files with 44 additions and 31 deletions
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64
synapse/federation/federation_base.py
View File

@ -20,7 +20,7 @@ import six
from twisted.internet import defer
from twisted.internet.defer import DeferredList
from synapse.api.constants import MAX_DEPTH, EventTypes, Membership
from synapse.api.constants import KNOWN_ROOM_VERSIONS, MAX_DEPTH, EventTypes, Membership
from synapse.api.errors import Codes, SynapseError
from synapse.crypto.event_signing import check_event_content_hash
from synapse.events import event_type_from_format_version
@ -66,7 +66,7 @@ class FederationBase(object):
Returns:
Deferred : A list of PDUs that have valid signatures and hashes.
"""
deferreds = self._check_sigs_and_hashes(pdus)
deferreds = self._check_sigs_and_hashes(room_version, pdus)
@defer.inlineCallbacks
def handle_check_result(pdu, deferred):
@ -121,16 +121,17 @@ class FederationBase(object):
else:
defer.returnValue([p for p in valid_pdus if p])
def _check_sigs_and_hash(self, pdu):
def _check_sigs_and_hash(self, room_version, pdu):
return logcontext.make_deferred_yieldable(
self._check_sigs_and_hashes([pdu])[0],
self._check_sigs_and_hashes(room_version, [pdu])[0],
)
def _check_sigs_and_hashes(self, pdus):
def _check_sigs_and_hashes(self, room_version, pdus):
"""Checks that each of the received events is correctly signed by the
sending server.
Args:
room_version (str): The room version of the PDUs
pdus (list[FrozenEvent]): the events to be checked
Returns:
@ -141,7 +142,7 @@ class FederationBase(object):
* throws a SynapseError if the signature check failed.
The deferreds run their callbacks in the sentinel logcontext.
"""
deferreds = _check_sigs_on_pdus(self.keyring, pdus)
deferreds = _check_sigs_on_pdus(self.keyring, room_version, pdus)
ctx = logcontext.LoggingContext.current_context()
@ -203,16 +204,17 @@ class FederationBase(object):
class PduToCheckSig(namedtuple("PduToCheckSig", [
"pdu", "redacted_pdu_json", "event_id_domain", "sender_domain", "deferreds",
"pdu", "redacted_pdu_json", "sender_domain", "deferreds",
])):
pass
def _check_sigs_on_pdus(keyring, pdus):
def _check_sigs_on_pdus(keyring, room_version, pdus):
"""Check that the given events are correctly signed
Args:
keyring (synapse.crypto.Keyring): keyring object to do the checks
room_version (str): the room version of the PDUs
pdus (Collection[EventBase]): the events to be checked
Returns:
@ -243,32 +245,22 @@ def _check_sigs_on_pdus(keyring, pdus):
#
# let's start by getting the domain for each pdu, and flattening the event back
# to JSON.
pdus_to_check = [
PduToCheckSig(
pdu=p,
redacted_pdu_json=prune_event(p).get_pdu_json(),
event_id_domain=get_domain_from_id(p.event_id),
sender_domain=get_domain_from_id(p.sender),
deferreds=[],
)
for p in pdus
]
# first make sure that the event is signed by the event_id's domain
deferreds = keyring.verify_json_objects_for_server([
(p.event_id_domain, p.redacted_pdu_json)
for p in pdus_to_check
])
for p, d in zip(pdus_to_check, deferreds):
p.deferreds.append(d)
# 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.
# 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 p.sender_domain != p.event_id_domain and not _is_invite_via_3pid(p.pdu)
if not _is_invite_via_3pid(p.pdu)
]
more_deferreds = keyring.verify_json_objects_for_server([
@ -279,19 +271,37 @@ def _check_sigs_on_pdus(keyring, pdus):
for p, d in zip(pdus_to_check_sender, more_deferreds):
p.deferreds.append(d)
# 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
if room_version in KNOWN_ROOM_VERSIONS:
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_json_objects_for_server([
(get_domain_from_id(p.pdu.event_id), p.redacted_pdu_json)
for p in pdus_to_check_event_id
])
for p, d in zip(pdus_to_check_event_id, more_deferreds):
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):
"""Given a list of one or more deferreds, either return the single deferred, or
combine into a DeferredList.
"""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)
else:
assert len(deferreds) == 1
elif len(deferreds) == 1:
return deferreds[0]
else:
return defer.succeed(None)
def _is_invite_via_3pid(event):
@ -319,7 +329,7 @@ def event_from_pdu_json(pdu_json, event_format_version, outlier=False):
"""
# we could probably enforce a bunch of other fields here (room_id, sender,
# origin, etc etc)
assert_params_in_dict(pdu_json, ('event_id', 'type', 'depth'))
assert_params_in_dict(pdu_json, ('type', 'depth'))
depth = pdu_json['depth']
if not isinstance(depth, six.integer_types):

6
synapse/federation/federation_client.py
View File

@ -205,7 +205,7 @@ class FederationClient(FederationBase):
# FIXME: We should handle signature failures more gracefully.
pdus[:] = yield logcontext.make_deferred_yieldable(defer.gatherResults(
self._check_sigs_and_hashes(pdus),
self._check_sigs_and_hashes(room_version, pdus),
consumeErrors=True,
).addErrback(unwrapFirstError))
@ -268,7 +268,7 @@ class FederationClient(FederationBase):
pdu = pdu_list[0]
# Check signatures are correct.
signed_pdu = yield self._check_sigs_and_hash(pdu)
signed_pdu = yield self._check_sigs_and_hash(room_version, pdu)
break
@ -757,7 +757,7 @@ class FederationClient(FederationBase):
pdu = event_from_pdu_json(pdu_dict, format_ver)
# Check signatures are correct.
pdu = yield self._check_sigs_and_hash(pdu)
pdu = yield self._check_sigs_and_hash(room_version, pdu)
# FIXME: We should handle signature failures more gracefully.

5
synapse/federation/federation_server.py
View File

@ -645,9 +645,12 @@ class FederationServer(FederationBase):
pdu.event_id, origin
)
# We've already checked that we know the room version by this point
room_version = yield self.store.get_room_version(pdu.room_id)
# Check signature.
try:
pdu = yield self._check_sigs_and_hash(pdu)
pdu = yield self._check_sigs_and_hash(room_version, pdu)
except SynapseError as e:
raise FederationError(
"ERROR",