From 33f469ba19586bbafa0cf2c7d7c35463bdab87eb Mon Sep 17 00:00:00 2001 From: Richard van der Hoff Date: Tue, 1 May 2018 16:19:39 +0100 Subject: Apply some limits to depth to counter abuse * When creating a new event, cap its depth to 2^63 - 1 * When receiving events, reject any without a sensible depth As per https://docs.google.com/document/d/1I3fi2S-XnpO45qrpCsowZv8P8dHcNZ4fsBsbOW7KABI --- synapse/federation/federation_base.py | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-) (limited to 'synapse/federation/federation_base.py') diff --git a/synapse/federation/federation_base.py b/synapse/federation/federation_base.py index 79eaa31031..4cc98a3fe8 100644 --- a/synapse/federation/federation_base.py +++ b/synapse/federation/federation_base.py @@ -14,7 +14,10 @@ # limitations under the License. import logging -from synapse.api.errors import SynapseError +import six + +from synapse.api.constants import MAX_DEPTH +from synapse.api.errors import SynapseError, Codes from synapse.crypto.event_signing import check_event_content_hash from synapse.events import FrozenEvent from synapse.events.utils import prune_event @@ -190,11 +193,23 @@ def event_from_pdu_json(pdu_json, outlier=False): FrozenEvent Raises: - SynapseError: if the pdu is missing required fields + SynapseError: if the pdu is missing required fields or is otherwise + not a valid matrix event """ # we could probably enforce a bunch of other fields here (room_id, sender, # origin, etc etc) - assert_params_in_request(pdu_json, ('event_id', 'type')) + assert_params_in_request(pdu_json, ('event_id', 'type', 'depth')) + + depth = pdu_json['depth'] + if not isinstance(depth, six.integer_types): + raise SynapseError(400, "Depth %r not an intger" % (depth, ), + Codes.BAD_JSON) + + if depth < 0: + raise SynapseError(400, "Depth too small", Codes.BAD_JSON) + elif depth > MAX_DEPTH: + raise SynapseError(400, "Depth too large", Codes.BAD_JSON) + event = FrozenEvent( pdu_json ) -- cgit 1.4.1