# -*- coding: utf-8 -*- # Copyright 2014 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. """This module contains classes for authenticating the user.""" from twisted.internet import defer from synapse.api.constants import Membership, JoinRules from synapse.api.errors import AuthError, StoreError, Codes, SynapseError from synapse.api.events.room import ( RoomMemberEvent, RoomPowerLevelsEvent, RoomRedactionEvent, RoomJoinRulesEvent, RoomCreateEvent, ) from synapse.util.logutils import log_function from syutil.base64util import encode_base64 import logging logger = logging.getLogger(__name__) class Auth(object): def __init__(self, hs): self.hs = hs self.store = hs.get_datastore() def check(self, event, raises=False): """ Checks if this event is correctly authed. Returns: True if the auth checks pass. Raises: AuthError if there was a problem authorising this event. This will be raised only if raises=True. """ try: if hasattr(event, "room_id"): if event.old_state_events is None: # Oh, we don't know what the state of the room was, so we # are trusting that this is allowed (at least for now) logger.warn("Trusting event: %s", event.event_id) return True if hasattr(event, "outlier") and event.outlier is True: # TODO (erikj): Auth for outliers is done differently. return True if event.type == RoomCreateEvent.TYPE: # FIXME return True if event.type == RoomMemberEvent.TYPE: allowed = self.is_membership_change_allowed(event) if allowed: logger.debug("Allowing! %s", event) else: logger.debug("Denying! %s", event) return allowed self._can_send_event(event) if event.type == RoomPowerLevelsEvent.TYPE: self._check_power_levels(event) if event.type == RoomRedactionEvent.TYPE: self._check_redaction(event) logger.debug("Allowing! %s", event) return True else: raise AuthError(500, "Unknown event: %s" % event) except AuthError as e: logger.info("Event auth check failed on event %s with msg: %s", event, e.msg) logger.info("Denying! %s", event) if raises: raise e return False @defer.inlineCallbacks def check_joined_room(self, room_id, user_id): try: member = yield self.store.get_room_member( room_id=room_id, user_id=user_id ) self._check_joined_room(member, user_id, room_id) defer.returnValue(member) except AttributeError: pass defer.returnValue(None) def check_event_sender_in_room(self, event): key = (RoomMemberEvent.TYPE, event.user_id, ) member_event = event.state_events.get(key) return self._check_joined_room( member_event, event.user_id, event.room_id ) def _check_joined_room(self, member, user_id, room_id): if not member or member.membership != Membership.JOIN: raise AuthError(403, "User %s not in room %s (%s)" % ( user_id, room_id, repr(member) )) @log_function def is_membership_change_allowed(self, event): target_user_id = event.state_key # get info about the caller key = (RoomMemberEvent.TYPE, event.user_id, ) caller = event.old_state_events.get(key) caller_in_room = caller and caller.membership == Membership.JOIN caller_invited = caller and caller.membership == Membership.INVITE # get info about the target key = (RoomMemberEvent.TYPE, target_user_id, ) target = event.old_state_events.get(key) target_in_room = target and target.membership == Membership.JOIN membership = event.content["membership"] key = (RoomJoinRulesEvent.TYPE, "", ) join_rule_event = event.old_state_events.get(key) if join_rule_event: join_rule = join_rule_event.content.get( "join_rule", JoinRules.INVITE ) else: join_rule = JoinRules.INVITE user_level = self._get_power_level_from_event_state( event, event.user_id, ) ban_level, kick_level, redact_level = ( self._get_ops_level_from_event_state( event ) ) logger.debug( "is_membership_change_allowed: %s", { "caller_in_room": caller_in_room, "caller_invited": caller_invited, "target_in_room": target_in_room, "membership": membership, "join_rule": join_rule, "target_user_id": target_user_id, "event.user_id": event.user_id, } ) if Membership.INVITE == membership: # TODO (erikj): We should probably handle this more intelligently # PRIVATE join rules. # Invites are valid iff caller is in the room and target isn't. if not caller_in_room: # caller isn't joined raise AuthError(403, "You are not in room %s." % event.room_id) elif target_in_room: # the target is already in the room. raise AuthError(403, "%s is already in the room." % target_user_id) elif Membership.JOIN == membership: # Joins are valid iff caller == target and they were: # invited: They are accepting the invitation # joined: It's a NOOP if event.user_id != target_user_id: raise AuthError(403, "Cannot force another user to join.") elif join_rule == JoinRules.PUBLIC: pass elif join_rule == JoinRules.INVITE: if not caller_in_room and not caller_invited: raise AuthError(403, "You are not invited to this room.") else: # TODO (erikj): may_join list # TODO (erikj): private rooms raise AuthError(403, "You are not allowed to join this room") elif Membership.LEAVE == membership: # TODO (erikj): Implement kicks. if not caller_in_room: # trying to leave a room you aren't joined raise AuthError(403, "You are not in room %s." % event.room_id) elif target_user_id != event.user_id: if kick_level: kick_level = int(kick_level) else: kick_level = 50 # FIXME (erikj): What should we do here? if user_level < kick_level: raise AuthError( 403, "You cannot kick user %s." % target_user_id ) elif Membership.BAN == membership: if ban_level: ban_level = int(ban_level) else: ban_level = 50 # FIXME (erikj): What should we do here? if user_level < ban_level: raise AuthError(403, "You don't have permission to ban") else: raise AuthError(500, "Unknown membership %s" % membership) return True def _get_power_level_from_event_state(self, event, user_id): key = (RoomPowerLevelsEvent.TYPE, "", ) power_level_event = event.old_state_events.get(key) level = None if power_level_event: level = power_level_event.content.get("users", {}).get(user_id) if not level: level = power_level_event.content.get("users_default", 0) return level def _get_ops_level_from_event_state(self, event): key = (RoomPowerLevelsEvent.TYPE, "", ) power_level_event = event.old_state_events.get(key) if power_level_event: return ( power_level_event.content.get("ban", 50), power_level_event.content.get("kick", 50), power_level_event.content.get("redact", 50), ) return None, None, None, @defer.inlineCallbacks def get_user_by_req(self, request): """ Get a registered user's ID. Args: request - An HTTP request with an access_token query parameter. Returns: UserID : User ID object of the user making the request Raises: AuthError if no user by that token exists or the token is invalid. """ # Can optionally look elsewhere in the request (e.g. headers) try: access_token = request.args["access_token"][0] user_info = yield self.get_user_by_token(access_token) user = user_info["user"] ip_addr = self.hs.get_ip_from_request(request) user_agent = request.requestHeaders.getRawHeaders( "User-Agent", default=[""] )[0] if user and access_token and ip_addr: self.store.insert_client_ip( user=user, access_token=access_token, device_id=user_info["device_id"], ip=ip_addr, user_agent=user_agent ) defer.returnValue(user) except KeyError: raise AuthError(403, "Missing access token.") @defer.inlineCallbacks def get_user_by_token(self, token): """ Get a registered user's ID. Args: token (str): The access token to get the user by. Returns: dict : dict that includes the user, device_id, and whether the user is a server admin. Raises: AuthError if no user by that token exists or the token is invalid. """ try: ret = yield self.store.get_user_by_token(token=token) if not ret: raise StoreError() user_info = { "admin": bool(ret.get("admin", False)), "device_id": ret.get("device_id"), "user": self.hs.parse_userid(ret.get("name")), } defer.returnValue(user_info) except StoreError: raise AuthError(403, "Unrecognised access token.", errcode=Codes.UNKNOWN_TOKEN) def is_server_admin(self, user): return self.store.is_server_admin(user) @defer.inlineCallbacks def add_auth_events(self, event): if event.type == RoomCreateEvent.TYPE: event.auth_events = [] return auth_events = [] key = (RoomPowerLevelsEvent.TYPE, "", ) power_level_event = event.old_state_events.get(key) if power_level_event: auth_events.append(power_level_event.event_id) key = (RoomJoinRulesEvent.TYPE, "", ) join_rule_event = event.old_state_events.get(key) key = (RoomMemberEvent.TYPE, event.user_id, ) member_event = event.old_state_events.get(key) if join_rule_event: join_rule = join_rule_event.content.get("join_rule") is_public = join_rule == JoinRules.PUBLIC if join_rule else False if event.type == RoomMemberEvent.TYPE: if event.content["membership"] == Membership.JOIN: if is_public: auth_events.append(join_rule_event.event_id) elif member_event: auth_events.append(member_event.event_id) if member_event: if member_event.content["membership"] == Membership.JOIN: auth_events.append(member_event.event_id) hashes = yield self.store.get_event_reference_hashes( auth_events ) hashes = [ { k: encode_base64(v) for k, v in h.items() if k == "sha256" } for h in hashes ] event.auth_events = zip(auth_events, hashes) @log_function def _can_send_event(self, event): key = (RoomPowerLevelsEvent.TYPE, "", ) send_level_event = event.old_state_events.get(key) send_level = None if send_level_event: send_level = send_level_event.content.get("events", {}).get( event.type ) if not send_level: if hasattr(event, "state_key"): send_level = send_level_event.content.get( "state_default", 50 ) else: send_level = send_level_event.content.get( "events_default", 0 ) if send_level: send_level = int(send_level) else: send_level = 0 user_level = self._get_power_level_from_event_state( event, event.user_id, ) if user_level: user_level = int(user_level) else: user_level = 0 if user_level < send_level: raise AuthError( 403, "You don't have permission to post that to the room" ) return True def _check_redaction(self, event): user_level = self._get_power_level_from_event_state( event, event.user_id, ) _, _, redact_level = self._get_ops_level_from_event_state( event ) if user_level < redact_level: raise AuthError( 403, "You don't have permission to redact events" ) def _check_power_levels(self, event): user_list = event.content.get("users", {}) # Validate users for k, v in user_list.items(): try: self.hs.parse_userid(k) except: raise SynapseError(400, "Not a valid user_id: %s" % (k,)) try: int(v) except: raise SynapseError(400, "Not a valid power level: %s" % (v,)) key = (event.type, event.state_key, ) current_state = event.old_state_events.get(key) if not current_state: return user_level = self._get_power_level_from_event_state( event, event.user_id, ) # Check other levels: levels_to_check = [ ("users_default", []), ("events_default", []), ("ban", []), ("redact", []), ("kick", []), ] old_list = current_state.content.get("users") for user in set(old_list.keys() + user_list.keys()): levels_to_check.append( (user, ["users"]) ) old_list = current_state.content.get("events") new_list = event.content.get("events") for ev_id in set(old_list.keys() + new_list.keys()): levels_to_check.append( (ev_id, ["events"]) ) old_state = current_state.content new_state = event.content for level_to_check, dir in levels_to_check: old_loc = old_state for d in dir: old_loc = old_loc.get(d, {}) new_loc = new_state for d in dir: new_loc = new_loc.get(d, {}) if level_to_check in old_loc: old_level = int(old_loc[level_to_check]) else: old_level = None if level_to_check in new_loc: new_level = int(new_loc[level_to_check]) else: new_level = None if new_level is not None and old_level is not None: if new_level == old_level: continue if old_level > user_level or new_level > user_level: raise AuthError( 403, "You don't have permission to add ops level greater " "than your own" )