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Strictly enforce canonicaljson requirements in a new room version (#7381)

This commit is contained in:
Patrick Cloke 2020-05-14 13:24:01 -04:00 committed by GitHub
parent ec0b72bc4e
commit 56b66db78a
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7 changed files with 137 additions and 5 deletions
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1
changelog.d/7381.bugfix Normal file
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@ -0,0 +1 @@
Add an experimental room version which strictly adheres to the canonical JSON specification.

24
synapse/api/room_versions.py
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@ -59,7 +59,11 @@ class RoomVersion(object):
# bool: before MSC2261/MSC2432, m.room.aliases had special auth rules and redaction rules
special_case_aliases_auth = attr.ib(type=bool)
# Strictly enforce canonicaljson, do not allow:
# * Integers outside the range of [-2 ^ 53 + 1, 2 ^ 53 - 1]
# * Floats
# * NaN, Infinity, -Infinity
strict_canonicaljson = attr.ib(type=bool)
# bool: MSC2209: Check 'notifications' key while verifying
# m.room.power_levels auth rules.
limit_notifications_power_levels = attr.ib(type=bool)
@ -73,6 +77,7 @@ class RoomVersions(object):
StateResolutionVersions.V1,
enforce_key_validity=False,
special_case_aliases_auth=True,
strict_canonicaljson=False,
limit_notifications_power_levels=False,
)
V2 = RoomVersion(
@ -82,6 +87,7 @@ class RoomVersions(object):
StateResolutionVersions.V2,
enforce_key_validity=False,
special_case_aliases_auth=True,
strict_canonicaljson=False,
limit_notifications_power_levels=False,
)
V3 = RoomVersion(
@ -91,6 +97,7 @@ class RoomVersions(object):
StateResolutionVersions.V2,
enforce_key_validity=False,
special_case_aliases_auth=True,
strict_canonicaljson=False,
limit_notifications_power_levels=False,
)
V4 = RoomVersion(
@ -100,6 +107,7 @@ class RoomVersions(object):
StateResolutionVersions.V2,
enforce_key_validity=False,
special_case_aliases_auth=True,
strict_canonicaljson=False,
limit_notifications_power_levels=False,
)
V5 = RoomVersion(
@ -109,6 +117,7 @@ class RoomVersions(object):
StateResolutionVersions.V2,
enforce_key_validity=True,
special_case_aliases_auth=True,
strict_canonicaljson=False,
limit_notifications_power_levels=False,
)
MSC2432_DEV = RoomVersion(
@ -118,6 +127,17 @@ class RoomVersions(object):
StateResolutionVersions.V2,
enforce_key_validity=True,
special_case_aliases_auth=False,
strict_canonicaljson=False,
limit_notifications_power_levels=False,
)
STRICT_CANONICALJSON = RoomVersion(
"org.matrix.strict_canonicaljson",
RoomDisposition.UNSTABLE,
EventFormatVersions.V3,
StateResolutionVersions.V2,
enforce_key_validity=True,
special_case_aliases_auth=True,
strict_canonicaljson=True,
limit_notifications_power_levels=False,
)
MSC2209_DEV = RoomVersion(
@ -127,6 +147,7 @@ class RoomVersions(object):
StateResolutionVersions.V2,
enforce_key_validity=True,
special_case_aliases_auth=True,
strict_canonicaljson=False,
limit_notifications_power_levels=True,
)
@ -140,6 +161,7 @@ KNOWN_ROOM_VERSIONS = {
RoomVersions.V4,
RoomVersions.V5,
RoomVersions.MSC2432_DEV,
RoomVersions.STRICT_CANONICALJSON,
RoomVersions.MSC2209_DEV,
)
} # type: Dict[str, RoomVersion]

35
synapse/events/utils.py
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@ -14,7 +14,7 @@
# limitations under the License.
import collections
import re
from typing import Mapping, Union
from typing import Any, Mapping, Union
from six import string_types
@ -23,6 +23,7 @@ from frozendict import frozendict
from twisted.internet import defer
from synapse.api.constants import EventTypes, RelationTypes
from synapse.api.errors import Codes, SynapseError
from synapse.api.room_versions import RoomVersion
from synapse.util.async_helpers import yieldable_gather_results
@ -449,3 +450,35 @@ def copy_power_levels_contents(
raise TypeError("Invalid power_levels value for %s: %r" % (k, v))
return power_levels
def validate_canonicaljson(value: Any):
"""
Ensure that the JSON object is valid according to the rules of canonical JSON.
See the appendix section 3.1: Canonical JSON.
This rejects JSON that has:
* An integer outside the range of [-2 ^ 53 + 1, 2 ^ 53 - 1]
* Floats
* NaN, Infinity, -Infinity
"""
if isinstance(value, int):
if value <= -(2 ** 53) or 2 ** 53 <= value:
raise SynapseError(400, "JSON integer out of range", Codes.BAD_JSON)
elif isinstance(value, float):
# Note that Infinity, -Infinity, and NaN are also considered floats.
raise SynapseError(400, "Bad JSON value: float", Codes.BAD_JSON)
elif isinstance(value, (dict, frozendict)):
for v in value.values():
validate_canonicaljson(v)
elif isinstance(value, (list, tuple)):
for i in value:
validate_canonicaljson(i)
elif not isinstance(value, (bool, str)) and value is not None:
# Other potential JSON values (bool, None, str) are safe.
raise SynapseError(400, "Unknown JSON value", Codes.BAD_JSON)

7
synapse/events/validator.py
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@ -18,6 +18,7 @@ from six import integer_types, 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.events.utils import validate_canonicaljson
from synapse.types import EventID, RoomID, UserID
@ -55,6 +56,12 @@ class EventValidator(object):
if not isinstance(getattr(event, s), string_types):
raise SynapseError(400, "'%s' not a string type" % (s,))
# Depending on the room version, ensure the data is spec compliant JSON.
if event.room_version.strict_canonicaljson:
# Note that only the client controlled portion of the event is
# checked, since we trust the portions of the event we created.
validate_canonicaljson(event.content)
if event.type == EventTypes.Aliases:
if "aliases" in event.content:
for alias in event.content["aliases"]:

6
synapse/federation/federation_base.py
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@ -29,7 +29,7 @@ from synapse.api.room_versions import EventFormatVersions, RoomVersion
from synapse.crypto.event_signing import check_event_content_hash
from synapse.crypto.keyring import Keyring
from synapse.events import EventBase, make_event_from_dict
from synapse.events.utils import prune_event
from synapse.events.utils import prune_event, validate_canonicaljson
from synapse.http.servlet import assert_params_in_dict
from synapse.logging.context import (
PreserveLoggingContext,
@ -302,6 +302,10 @@ def event_from_pdu_json(
elif depth > MAX_DEPTH:
raise SynapseError(400, "Depth too large", Codes.BAD_JSON)
# Validate that the JSON conforms to the specification.
if room_version.strict_canonicaljson:
validate_canonicaljson(pdu_json)
event = make_event_from_dict(pdu_json, room_version)
event.internal_metadata.outlier = outlier

2
synapse/util/frozenutils.py
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@ -65,5 +65,5 @@ def _handle_frozendict(obj):
)
# A JSONEncoder which is capable of encoding frozendics without barfing
# A JSONEncoder which is capable of encoding frozendicts without barfing
frozendict_json_encoder = json.JSONEncoder(default=_handle_frozendict)

67
tests/handlers/test_federation.py
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@ -13,9 +13,12 @@
# See the License for the specific language governing permissions and
# limitations under the License.
import logging
from unittest import TestCase
from synapse.api.constants import EventTypes
from synapse.api.errors import AuthError, Codes
from synapse.api.errors import AuthError, Codes, SynapseError
from synapse.api.room_versions import RoomVersions
from synapse.events import EventBase
from synapse.federation.federation_base import event_from_pdu_json
from synapse.logging.context import LoggingContext, run_in_background
from synapse.rest import admin
@ -207,3 +210,65 @@ class FederationTestCase(unittest.HomeserverTestCase):
self.assertEqual(r[(EventTypes.Member, other_user)], join_event.event_id)
return join_event
class EventFromPduTestCase(TestCase):
def test_valid_json(self):
"""Valid JSON should be turned into an event."""
ev = event_from_pdu_json(
{
"type": EventTypes.Message,
"content": {"bool": True, "null": None, "int": 1, "str": "foobar"},
"room_id": "!room:test",
"sender": "@user:test",
"depth": 1,
"prev_events": [],
"auth_events": [],
"origin_server_ts": 1234,
},
RoomVersions.STRICT_CANONICALJSON,
)
self.assertIsInstance(ev, EventBase)
def test_invalid_numbers(self):
"""Invalid values for an integer should be rejected, all floats should be rejected."""
for value in [
-(2 ** 53),
2 ** 53,
1.0,
float("inf"),
float("-inf"),
float("nan"),
]:
with self.assertRaises(SynapseError):
event_from_pdu_json(
{
"type": EventTypes.Message,
"content": {"foo": value},
"room_id": "!room:test",
"sender": "@user:test",
"depth": 1,
"prev_events": [],
"auth_events": [],
"origin_server_ts": 1234,
},
RoomVersions.STRICT_CANONICALJSON,
)
def test_invalid_nested(self):
"""List and dictionaries are recursively searched."""
with self.assertRaises(SynapseError):
event_from_pdu_json(
{
"type": EventTypes.Message,
"content": {"foo": [{"bar": 2 ** 56}]},
"room_id": "!room:test",
"sender": "@user:test",
"depth": 1,
"prev_events": [],
"auth_events": [],
"origin_server_ts": 1234,
},
RoomVersions.STRICT_CANONICALJSON,
)