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- # 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.
- import collections.abc
- from typing import Iterable, List, Type, Union, cast
- import jsonschema
- from pydantic import Field, StrictBool, StrictStr
- from synapse.api.constants import (
- MAX_ALIAS_LENGTH,
- EventContentFields,
- EventTypes,
- Membership,
- )
- from synapse.api.errors import Codes, SynapseError
- from synapse.api.room_versions import EventFormatVersions
- from synapse.config.homeserver import HomeServerConfig
- from synapse.events import EventBase
- from synapse.events.builder import EventBuilder
- from synapse.events.utils import (
- CANONICALJSON_MAX_INT,
- CANONICALJSON_MIN_INT,
- validate_canonicaljson,
- )
- from synapse.federation.federation_server import server_matches_acl_event
- from synapse.http.servlet import validate_json_object
- from synapse.rest.models import RequestBodyModel
- from synapse.types import EventID, JsonDict, RoomID, UserID
- class EventValidator:
- def validate_new(self, event: EventBase, config: HomeServerConfig) -> None:
- """Validates the event has roughly the right format
- Suitable for checking a locally-created event. It has stricter checks than
- is appropriate for an event received over federation (for which, see
- event_auth.validate_event_for_room_version)
- Args:
- event: The event to validate.
- config: The homeserver's configuration.
- """
- self.validate_builder(event)
- if event.format_version == EventFormatVersions.ROOM_V1_V2:
- EventID.from_string(event.event_id)
- required = [
- "auth_events",
- "content",
- "hashes",
- "origin",
- "prev_events",
- "sender",
- "type",
- ]
- for k in required:
- if k not in event:
- 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), str):
- 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"]:
- if len(alias) > MAX_ALIAS_LENGTH:
- raise SynapseError(
- 400,
- (
- "Can't create aliases longer than"
- " %d characters" % (MAX_ALIAS_LENGTH,)
- ),
- Codes.INVALID_PARAM,
- )
- elif event.type == EventTypes.Retention:
- self._validate_retention(event)
- elif event.type == EventTypes.ServerACL:
- if not server_matches_acl_event(config.server.server_name, event):
- raise SynapseError(
- 400, "Can't create an ACL event that denies the local server"
- )
- elif event.type == EventTypes.PowerLevels:
- try:
- jsonschema.validate(
- instance=event.content,
- schema=POWER_LEVELS_SCHEMA,
- cls=POWER_LEVELS_VALIDATOR,
- )
- except jsonschema.ValidationError as e:
- if e.path:
- # example: "users_default": '0' is not of type 'integer'
- # cast safety: path entries can be integers, if we fail to validate
- # items in an array. However, the POWER_LEVELS_SCHEMA doesn't expect
- # to see any arrays.
- message = (
- '"' + cast(str, e.path[-1]) + '": ' + e.message # noqa: B306
- )
- # jsonschema.ValidationError.message is a valid attribute
- else:
- # example: '0' is not of type 'integer'
- message = e.message # noqa: B306
- # jsonschema.ValidationError.message is a valid attribute
- raise SynapseError(
- code=400,
- msg=message,
- errcode=Codes.BAD_JSON,
- )
- # If the event contains a mentions key, validate it.
- if (
- EventContentFields.MSC3952_MENTIONS in event.content
- and config.experimental.msc3952_intentional_mentions
- ):
- validate_json_object(
- event.content[EventContentFields.MSC3952_MENTIONS], Mentions
- )
- def _validate_retention(self, event: EventBase) -> None:
- """Checks that an event that defines the retention policy for a room respects the
- format enforced by the spec.
- Args:
- event: The event to validate.
- """
- if not event.is_state():
- raise SynapseError(code=400, msg="must be a state event")
- min_lifetime = event.content.get("min_lifetime")
- max_lifetime = event.content.get("max_lifetime")
- if min_lifetime is not None:
- if type(min_lifetime) is not int:
- raise SynapseError(
- code=400,
- msg="'min_lifetime' must be an integer",
- errcode=Codes.BAD_JSON,
- )
- if max_lifetime is not None:
- if type(max_lifetime) is not int:
- raise SynapseError(
- code=400,
- msg="'max_lifetime' must be an integer",
- errcode=Codes.BAD_JSON,
- )
- if (
- min_lifetime is not None
- and max_lifetime is not None
- and min_lifetime > max_lifetime
- ):
- raise SynapseError(
- code=400,
- msg="'min_lifetime' can't be greater than 'max_lifetime",
- errcode=Codes.BAD_JSON,
- )
- def validate_builder(self, event: Union[EventBase, EventBuilder]) -> 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
- """
- strings = ["room_id", "sender", "type"]
- if hasattr(event, "state_key"):
- strings.append("state_key")
- for s in strings:
- if not isinstance(getattr(event, s), str):
- 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 the room it was sent in"
- )
- self._ensure_state_event(event)
- def _ensure_strings(self, d: JsonDict, keys: Iterable[str]) -> None:
- for s in keys:
- if s not in d:
- raise SynapseError(400, "'%s' not in content" % (s,))
- if not isinstance(d[s], str):
- raise SynapseError(400, "'%s' not a string type" % (s,))
- def _ensure_state_event(self, event: Union[EventBase, EventBuilder]) -> None:
- if not event.is_state():
- raise SynapseError(400, "'%s' must be state events" % (event.type,))
- POWER_LEVELS_SCHEMA = {
- "type": "object",
- "properties": {
- "ban": {"$ref": "#/definitions/int"},
- "events": {"$ref": "#/definitions/objectOfInts"},
- "events_default": {"$ref": "#/definitions/int"},
- "invite": {"$ref": "#/definitions/int"},
- "kick": {"$ref": "#/definitions/int"},
- "notifications": {"$ref": "#/definitions/objectOfInts"},
- "redact": {"$ref": "#/definitions/int"},
- "state_default": {"$ref": "#/definitions/int"},
- "users": {"$ref": "#/definitions/objectOfInts"},
- "users_default": {"$ref": "#/definitions/int"},
- },
- "definitions": {
- "int": {
- "type": "integer",
- "minimum": CANONICALJSON_MIN_INT,
- "maximum": CANONICALJSON_MAX_INT,
- },
- "objectOfInts": {
- "type": "object",
- "additionalProperties": {"$ref": "#/definitions/int"},
- },
- },
- }
- class Mentions(RequestBodyModel):
- user_ids: List[StrictStr] = Field(default_factory=list)
- room: StrictBool = False
- # This could return something newer than Draft 7, but that's the current "latest"
- # validator.
- def _create_validator(schema: JsonDict) -> Type[jsonschema.Draft7Validator]:
- validator = jsonschema.validators.validator_for(schema)
- # by default jsonschema does not consider a immutabledict to be an object so
- # we need to use a custom type checker
- # https://python-jsonschema.readthedocs.io/en/stable/validate/?highlight=object#validating-with-additional-types
- type_checker = validator.TYPE_CHECKER.redefine(
- "object", lambda checker, thing: isinstance(thing, collections.abc.Mapping)
- )
- return jsonschema.validators.extend(validator, type_checker=type_checker)
- POWER_LEVELS_VALIDATOR = _create_validator(POWER_LEVELS_SCHEMA)
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