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-rw-r--r--synapse/api/room_versions.py24
-rw-r--r--synapse/events/utils.py35
-rw-r--r--synapse/events/validator.py7
-rw-r--r--synapse/federation/federation_base.py6
-rw-r--r--synapse/util/frozenutils.py2
5 files changed, 70 insertions, 4 deletions
diff --git a/synapse/api/room_versions.py b/synapse/api/room_versions.py
index af3612ed61..0901afb900 100644
--- a/synapse/api/room_versions.py
+++ b/synapse/api/room_versions.py
@@ -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]
diff --git a/synapse/events/utils.py b/synapse/events/utils.py
index b75b097e5e..dd340be9a7 100644
--- a/synapse/events/utils.py
+++ b/synapse/events/utils.py
@@ -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)
diff --git a/synapse/events/validator.py b/synapse/events/validator.py
index 9b90c9ce04..b001c64bb4 100644
--- a/synapse/events/validator.py
+++ b/synapse/events/validator.py
@@ -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"]:
diff --git a/synapse/federation/federation_base.py b/synapse/federation/federation_base.py
index 4b115aac04..c0012c6872 100644
--- a/synapse/federation/federation_base.py
+++ b/synapse/federation/federation_base.py
@@ -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
 
diff --git a/synapse/util/frozenutils.py b/synapse/util/frozenutils.py
index f2ccd5e7c6..9815bb8667 100644
--- a/synapse/util/frozenutils.py
+++ b/synapse/util/frozenutils.py
@@ -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)
generated by cgit-pink 1.4.1 (git 2.36.1) at 2024-09-20 13:37:32 +0000