forked-synapse/synapse/events/validator.py
Erik Johnston dc4d74e44a Validate well-known state events are state events.
Lets disallow sending things like memberships, topics etc as non-state
events.
2019-07-31 16:36:20 +01:00

129 lines
4.5 KiB
Python

# -*- coding: utf-8 -*-
# Copyright 2014-2016 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 six import string_types
from synapse.api.constants import MAX_ALIAS_LENGTH, EventTypes, Membership
from synapse.api.errors import Codes, SynapseError
from synapse.api.room_versions import EventFormatVersions
from synapse.types import EventID, RoomID, UserID
class EventValidator(object):
def validate_new(self, event):
"""Validates the event has roughly the right format
Args:
event (FrozenEvent)
"""
self.validate_builder(event)
if event.format_version == EventFormatVersions.V1:
EventID.from_string(event.event_id)
required = [
"auth_events",
"content",
"hashes",
"origin",
"prev_events",
"sender",
"type",
]
for k in required:
if not hasattr(event, k):
raise SynapseError(400, "Event does not have key %s" % (k,))
# Check that the following keys have string values
event_strings = ["origin"]
for s in event_strings:
if not isinstance(getattr(event, s), string_types):
raise SynapseError(400, "'%s' not a string type" % (s,))
if event.type == EventTypes.Aliases:
if "aliases" in event.content:
for alias in event.content["aliases"]:
if len(alias) > MAX_ALIAS_LENGTH:
raise SynapseError(
400,
(
"Can't create aliases longer than"
" %d characters" % (MAX_ALIAS_LENGTH,)
),
Codes.INVALID_PARAM,
)
def validate_builder(self, event):
"""Validates that the builder/event has roughly the right format. Only
checks values that we expect a proto event to have, rather than all the
fields an event would have
Args:
event (EventBuilder|FrozenEvent)
"""
strings = ["room_id", "sender", "type"]
if hasattr(event, "state_key"):
strings.append("state_key")
for s in strings:
if not isinstance(getattr(event, s), string_types):
raise SynapseError(400, "Not '%s' a string type" % (s,))
RoomID.from_string(event.room_id)
UserID.from_string(event.sender)
if event.type == EventTypes.Message:
strings = ["body", "msgtype"]
self._ensure_strings(event.content, strings)
elif event.type == EventTypes.Topic:
self._ensure_strings(event.content, ["topic"])
self._ensure_state_event(event)
elif event.type == EventTypes.Name:
self._ensure_strings(event.content, ["name"])
self._ensure_state_event(event)
elif event.type == EventTypes.Member:
if "membership" not in event.content:
raise SynapseError(400, "Content has not membership key")
if event.content["membership"] not in Membership.LIST:
raise SynapseError(400, "Invalid membership key")
self._ensure_state_event(event)
elif event.type == EventTypes.Tombstone:
if "replacement_room" not in event.content:
raise SynapseError(400, "Content has no replacement_room key")
if event.content["replacement_room"] == event.room_id:
raise SynapseError(400, "Tombstone cannot reference itself")
self._ensure_state_event(event)
def _ensure_strings(self, d, keys):
for s in keys:
if s not in d:
raise SynapseError(400, "'%s' not in content" % (s,))
if not isinstance(d[s], string_types):
raise SynapseError(400, "'%s' not a string type" % (s,))
def _ensure_state_event(self, event):
if not event.is_state():
raise SynapseError(400, "'%s' must be state events" % (event.type,))