Allow bypassing unnecessary validation in C-S API

synapse/events/validator.py

@@ -43,7 +43,7 @@ class EventValidator:
             event: The event to validate.
             config: The homeserver's configuration.
         """
-        self.validate_builder(event)
+        self.validate_builder(event, config)
 
         if event.format_version == EventFormatVersions.ROOM_V1_V2:
             EventID.from_string(event.event_id)
@@ -74,6 +74,12 @@ class EventValidator:
             # 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 not 0 < event.origin_server_ts < 2**53:
+            raise SynapseError(400, "Event timestamp is out of range")
+
+        # meow: allow specific users to send potentially dangerous events.
+        if event.sender in config.meow.validation_override:
+            return
 
         if event.type == EventTypes.Aliases:
             if "aliases" in event.content:
@@ -165,7 +171,9 @@ class EventValidator:
                 errcode=Codes.BAD_JSON,
             )
 
-    def validate_builder(self, event: Union[EventBase, EventBuilder]) -> None:
+    def validate_builder(
+        self, event: Union[EventBase, EventBuilder], config: HomeServerConfig
+    ) -> None:
         """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
@@ -183,6 +191,10 @@ class EventValidator:
         RoomID.from_string(event.room_id)
         UserID.from_string(event.sender)
 
+        # meow: allow specific users to send so-called invalid events
+        if event.sender in config.meow.validation_override:
+            return
+
         if event.type == EventTypes.Message:
             strings = ["body", "msgtype"]
 

synapse/handlers/directory.py

@@ -71,6 +71,8 @@ class DirectoryHandler:
     ) -> None:
         # general association creation for both human users and app services
 
+        # meow: allow specific users to include anything in room aliases
+        if creator not in self.config.meow.validation_override:
             for wchar in string.whitespace:
                 if wchar in room_alias.localpart:
                     raise SynapseError(400, "Invalid characters in room alias")
@@ -118,7 +120,10 @@ class DirectoryHandler:
         user_id = requester.user.to_string()
         room_alias_str = room_alias.to_string()
 
-        if len(room_alias_str) > MAX_ALIAS_LENGTH:
+        if (
+            user_id not in self.hs.config.meow.validation_override
+            and len(room_alias_str) > MAX_ALIAS_LENGTH
+        ):
             raise SynapseError(
                 400,
                 "Can't create aliases longer than %s characters" % MAX_ALIAS_LENGTH,

synapse/handlers/federation.py

@@ -1397,7 +1397,7 @@ class FederationHandler:
                 room_version_obj, event_dict
             )
 
-            EventValidator().validate_builder(builder)
+            EventValidator().validate_builder(builder, self.hs.config)
 
             # Try several times, it could fail with PartialStateConflictError
             # in send_membership_event, cf comment in except block.
@@ -1556,7 +1556,7 @@ class FederationHandler:
         builder = self.event_builder_factory.for_room_version(
             room_version_obj, event_dict
         )
-        EventValidator().validate_builder(builder)
+        EventValidator().validate_builder(builder, self.hs.config)
         event, context = await self.event_creation_handler.create_new_client_event(
             builder=builder
         )

synapse/handlers/message.py

@@ -669,7 +669,7 @@ class EventCreationHandler:
             room_version_obj, event_dict
         )
 
-        self.validator.validate_builder(builder)
+        self.validator.validate_builder(builder, self.config)
 
         if builder.type == EventTypes.Member:
             membership = builder.content.get("membership", None)
@@ -1292,6 +1292,8 @@ class EventCreationHandler:
         Raises:
             SynapseError if the event is invalid.
         """
+        if event.sender in self.config.meow.validation_override:
+            return
 
         relation = relation_from_event(event)
         if not relation:
@@ -1701,7 +1703,8 @@ class EventCreationHandler:
 
             await self._maybe_kick_guest_users(event, context)
 
-            if event.type == EventTypes.CanonicalAlias:
+            validation_override = event.sender in self.config.meow.validation_override
+            if event.type == EventTypes.CanonicalAlias and not validation_override:
                 # Validate a newly added alias or newly added alt_aliases.
 
                 original_alias = None
@@ -2092,7 +2095,7 @@ class EventCreationHandler:
             builder = self.event_builder_factory.for_room_version(
                 original_event.room_version, third_party_result
             )
-            self.validator.validate_builder(builder)
+            self.validator.validate_builder(builder, self.config)
         except SynapseError as e:
             raise Exception(
                 "Third party rules module created an invalid event: " + e.msg,

synapse/handlers/room_member.py

@@ -707,26 +707,6 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
             content.pop("displayname", None)
             content.pop("avatar_url", None)
 
-        if len(content.get("displayname") or "") > MAX_DISPLAYNAME_LEN:
-            raise SynapseError(
-                400,
-                f"Displayname is too long (max {MAX_DISPLAYNAME_LEN})",
-                errcode=Codes.BAD_JSON,
-            )
-
-        if len(content.get("avatar_url") or "") > MAX_AVATAR_URL_LEN:
-            raise SynapseError(
-                400,
-                f"Avatar URL is too long (max {MAX_AVATAR_URL_LEN})",
-                errcode=Codes.BAD_JSON,
-            )
-
-        if "avatar_url" in content and content.get("avatar_url") is not None:
-            if not await self.profile_handler.check_avatar_size_and_mime_type(
-                content["avatar_url"],
-            ):
-                raise SynapseError(403, "This avatar is not allowed", Codes.FORBIDDEN)
-
         # The event content should *not* include the authorising user as
         # it won't be properly signed. Strip it out since it might come
         # back from a client updating a display name / avatar.