508 lines
17 KiB
Python
508 lines
17 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright 2014 OpenMarket Ltd
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""This module contains classes for authenticating the user."""
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from twisted.internet import defer
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from synapse.api.constants import Membership, JoinRules
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from synapse.api.errors import AuthError, StoreError, Codes, SynapseError
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from synapse.api.events.room import (
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RoomMemberEvent, RoomPowerLevelsEvent, RoomRedactionEvent,
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RoomJoinRulesEvent, RoomCreateEvent,
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)
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from synapse.util.logutils import log_function
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from syutil.base64util import encode_base64
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import logging
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logger = logging.getLogger(__name__)
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class Auth(object):
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def __init__(self, hs):
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self.hs = hs
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self.store = hs.get_datastore()
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def check(self, event, raises=False):
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""" Checks if this event is correctly authed.
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Returns:
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True if the auth checks pass.
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Raises:
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AuthError if there was a problem authorising this event. This will
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be raised only if raises=True.
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"""
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try:
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if hasattr(event, "room_id"):
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if event.old_state_events is None:
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# Oh, we don't know what the state of the room was, so we
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# are trusting that this is allowed (at least for now)
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logger.warn("Trusting event: %s", event.event_id)
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return True
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if hasattr(event, "outlier") and event.outlier is True:
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# TODO (erikj): Auth for outliers is done differently.
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return True
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if event.type == RoomCreateEvent.TYPE:
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# FIXME
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return True
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if event.type == RoomMemberEvent.TYPE:
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allowed = self.is_membership_change_allowed(event)
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if allowed:
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logger.debug("Allowing! %s", event)
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else:
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logger.debug("Denying! %s", event)
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return allowed
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self._can_send_event(event)
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if event.type == RoomPowerLevelsEvent.TYPE:
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self._check_power_levels(event)
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if event.type == RoomRedactionEvent.TYPE:
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self._check_redaction(event)
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logger.debug("Allowing! %s", event)
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return True
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else:
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raise AuthError(500, "Unknown event: %s" % event)
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except AuthError as e:
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logger.info("Event auth check failed on event %s with msg: %s",
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event, e.msg)
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logger.info("Denying! %s", event)
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if raises:
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raise e
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return False
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@defer.inlineCallbacks
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def check_joined_room(self, room_id, user_id):
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try:
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member = yield self.store.get_room_member(
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room_id=room_id,
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user_id=user_id
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)
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self._check_joined_room(member, user_id, room_id)
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defer.returnValue(member)
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except AttributeError:
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pass
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defer.returnValue(None)
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@defer.inlineCallbacks
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def check_host_in_room(self, room_id, host):
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joined_hosts = yield self.store.get_joined_hosts_for_room(room_id)
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defer.returnValue(host in joined_hosts)
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def check_event_sender_in_room(self, event):
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key = (RoomMemberEvent.TYPE, event.user_id, )
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member_event = event.state_events.get(key)
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return self._check_joined_room(
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member_event,
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event.user_id,
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event.room_id
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)
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def _check_joined_room(self, member, user_id, room_id):
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if not member or member.membership != Membership.JOIN:
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raise AuthError(403, "User %s not in room %s (%s)" % (
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user_id, room_id, repr(member)
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))
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@log_function
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def is_membership_change_allowed(self, event):
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target_user_id = event.state_key
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# get info about the caller
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key = (RoomMemberEvent.TYPE, event.user_id, )
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caller = event.old_state_events.get(key)
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caller_in_room = caller and caller.membership == Membership.JOIN
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caller_invited = caller and caller.membership == Membership.INVITE
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# get info about the target
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key = (RoomMemberEvent.TYPE, target_user_id, )
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target = event.old_state_events.get(key)
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target_in_room = target and target.membership == Membership.JOIN
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membership = event.content["membership"]
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key = (RoomJoinRulesEvent.TYPE, "", )
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join_rule_event = event.old_state_events.get(key)
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if join_rule_event:
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join_rule = join_rule_event.content.get(
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"join_rule", JoinRules.INVITE
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)
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else:
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join_rule = JoinRules.INVITE
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user_level = self._get_power_level_from_event_state(
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event,
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event.user_id,
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)
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ban_level, kick_level, redact_level = (
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self._get_ops_level_from_event_state(
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event
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)
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)
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logger.debug(
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"is_membership_change_allowed: %s",
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{
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"caller_in_room": caller_in_room,
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"caller_invited": caller_invited,
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"target_in_room": target_in_room,
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"membership": membership,
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"join_rule": join_rule,
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"target_user_id": target_user_id,
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"event.user_id": event.user_id,
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}
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)
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if Membership.INVITE == membership:
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# TODO (erikj): We should probably handle this more intelligently
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# PRIVATE join rules.
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# Invites are valid iff caller is in the room and target isn't.
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if not caller_in_room: # caller isn't joined
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raise AuthError(403, "You are not in room %s." % event.room_id)
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elif target_in_room: # the target is already in the room.
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raise AuthError(403, "%s is already in the room." %
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target_user_id)
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elif Membership.JOIN == membership:
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# Joins are valid iff caller == target and they were:
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# invited: They are accepting the invitation
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# joined: It's a NOOP
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if event.user_id != target_user_id:
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raise AuthError(403, "Cannot force another user to join.")
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elif join_rule == JoinRules.PUBLIC:
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pass
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elif join_rule == JoinRules.INVITE:
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if not caller_in_room and not caller_invited:
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raise AuthError(403, "You are not invited to this room.")
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else:
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# TODO (erikj): may_join list
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# TODO (erikj): private rooms
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raise AuthError(403, "You are not allowed to join this room")
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elif Membership.LEAVE == membership:
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# TODO (erikj): Implement kicks.
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if not caller_in_room: # trying to leave a room you aren't joined
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raise AuthError(403, "You are not in room %s." % event.room_id)
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elif target_user_id != event.user_id:
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if kick_level:
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kick_level = int(kick_level)
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else:
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kick_level = 50 # FIXME (erikj): What should we do here?
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if user_level < kick_level:
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raise AuthError(
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403, "You cannot kick user %s." % target_user_id
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)
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elif Membership.BAN == membership:
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if ban_level:
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ban_level = int(ban_level)
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else:
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ban_level = 50 # FIXME (erikj): What should we do here?
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if user_level < ban_level:
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raise AuthError(403, "You don't have permission to ban")
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else:
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raise AuthError(500, "Unknown membership %s" % membership)
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return True
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def _get_power_level_from_event_state(self, event, user_id):
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key = (RoomPowerLevelsEvent.TYPE, "", )
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power_level_event = event.old_state_events.get(key)
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level = None
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if power_level_event:
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level = power_level_event.content.get("users", {}).get(user_id)
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if not level:
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level = power_level_event.content.get("users_default", 0)
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return level
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def _get_ops_level_from_event_state(self, event):
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key = (RoomPowerLevelsEvent.TYPE, "", )
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power_level_event = event.old_state_events.get(key)
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if power_level_event:
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return (
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power_level_event.content.get("ban", 50),
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power_level_event.content.get("kick", 50),
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power_level_event.content.get("redact", 50),
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)
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return None, None, None,
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@defer.inlineCallbacks
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def get_user_by_req(self, request):
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""" Get a registered user's ID.
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Args:
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request - An HTTP request with an access_token query parameter.
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Returns:
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UserID : User ID object of the user making the request
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Raises:
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AuthError if no user by that token exists or the token is invalid.
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"""
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# Can optionally look elsewhere in the request (e.g. headers)
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try:
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access_token = request.args["access_token"][0]
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user_info = yield self.get_user_by_token(access_token)
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user = user_info["user"]
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ip_addr = self.hs.get_ip_from_request(request)
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user_agent = request.requestHeaders.getRawHeaders(
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"User-Agent",
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default=[""]
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)[0]
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if user and access_token and ip_addr:
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self.store.insert_client_ip(
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user=user,
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access_token=access_token,
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device_id=user_info["device_id"],
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ip=ip_addr,
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user_agent=user_agent
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)
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defer.returnValue(user)
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except KeyError:
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raise AuthError(403, "Missing access token.")
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@defer.inlineCallbacks
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def get_user_by_token(self, token):
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""" Get a registered user's ID.
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Args:
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token (str): The access token to get the user by.
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Returns:
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dict : dict that includes the user, device_id, and whether the
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user is a server admin.
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Raises:
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AuthError if no user by that token exists or the token is invalid.
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"""
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try:
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ret = yield self.store.get_user_by_token(token=token)
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if not ret:
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raise StoreError()
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user_info = {
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"admin": bool(ret.get("admin", False)),
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"device_id": ret.get("device_id"),
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"user": self.hs.parse_userid(ret.get("name")),
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}
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defer.returnValue(user_info)
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except StoreError:
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raise AuthError(403, "Unrecognised access token.",
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errcode=Codes.UNKNOWN_TOKEN)
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def is_server_admin(self, user):
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return self.store.is_server_admin(user)
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@defer.inlineCallbacks
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def add_auth_events(self, event):
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if event.type == RoomCreateEvent.TYPE:
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event.auth_events = []
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return
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auth_events = []
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key = (RoomPowerLevelsEvent.TYPE, "", )
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power_level_event = event.old_state_events.get(key)
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if power_level_event:
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auth_events.append(power_level_event.event_id)
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key = (RoomJoinRulesEvent.TYPE, "", )
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join_rule_event = event.old_state_events.get(key)
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key = (RoomMemberEvent.TYPE, event.user_id, )
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member_event = event.old_state_events.get(key)
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if join_rule_event:
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join_rule = join_rule_event.content.get("join_rule")
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is_public = join_rule == JoinRules.PUBLIC if join_rule else False
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else:
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is_public = False
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if event.type == RoomMemberEvent.TYPE:
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e_type = event.content["membership"]
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if e_type in [Membership.JOIN, Membership.INVITE]:
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auth_events.append(join_rule_event.event_id)
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if member_event and not is_public:
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auth_events.append(member_event.event_id)
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elif member_event:
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if member_event.content["membership"] == Membership.JOIN:
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auth_events.append(member_event.event_id)
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hashes = yield self.store.get_event_reference_hashes(
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auth_events
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)
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hashes = [
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{
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k: encode_base64(v) for k, v in h.items()
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if k == "sha256"
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}
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for h in hashes
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]
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event.auth_events = zip(auth_events, hashes)
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@log_function
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def _can_send_event(self, event):
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key = (RoomPowerLevelsEvent.TYPE, "", )
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send_level_event = event.old_state_events.get(key)
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send_level = None
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if send_level_event:
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send_level = send_level_event.content.get("events", {}).get(
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event.type
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)
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if not send_level:
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if hasattr(event, "state_key"):
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send_level = send_level_event.content.get(
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"state_default", 50
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)
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else:
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send_level = send_level_event.content.get(
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"events_default", 0
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)
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if send_level:
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send_level = int(send_level)
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else:
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send_level = 0
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user_level = self._get_power_level_from_event_state(
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event,
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event.user_id,
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)
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if user_level:
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user_level = int(user_level)
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else:
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user_level = 0
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if user_level < send_level:
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raise AuthError(
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403, "You don't have permission to post that to the room"
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)
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return True
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def _check_redaction(self, event):
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user_level = self._get_power_level_from_event_state(
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event,
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event.user_id,
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)
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_, _, redact_level = self._get_ops_level_from_event_state(
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event
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)
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if user_level < redact_level:
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raise AuthError(
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403,
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"You don't have permission to redact events"
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)
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def _check_power_levels(self, event):
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user_list = event.content.get("users", {})
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# Validate users
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for k, v in user_list.items():
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try:
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self.hs.parse_userid(k)
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except:
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raise SynapseError(400, "Not a valid user_id: %s" % (k,))
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try:
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int(v)
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except:
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raise SynapseError(400, "Not a valid power level: %s" % (v,))
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key = (event.type, event.state_key, )
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current_state = event.old_state_events.get(key)
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if not current_state:
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return
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user_level = self._get_power_level_from_event_state(
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event,
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event.user_id,
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)
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# Check other levels:
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levels_to_check = [
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("users_default", []),
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("events_default", []),
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("ban", []),
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("redact", []),
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("kick", []),
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]
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old_list = current_state.content.get("users")
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for user in set(old_list.keys() + user_list.keys()):
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levels_to_check.append(
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(user, ["users"])
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)
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old_list = current_state.content.get("events")
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new_list = event.content.get("events")
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for ev_id in set(old_list.keys() + new_list.keys()):
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levels_to_check.append(
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(ev_id, ["events"])
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)
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old_state = current_state.content
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new_state = event.content
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for level_to_check, dir in levels_to_check:
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old_loc = old_state
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for d in dir:
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old_loc = old_loc.get(d, {})
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new_loc = new_state
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for d in dir:
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new_loc = new_loc.get(d, {})
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if level_to_check in old_loc:
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old_level = int(old_loc[level_to_check])
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else:
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old_level = None
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if level_to_check in new_loc:
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new_level = int(new_loc[level_to_check])
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else:
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new_level = None
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if new_level is not None and old_level is not None:
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if new_level == old_level:
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continue
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if old_level > user_level or new_level > user_level:
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raise AuthError(
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403,
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"You don't have permission to add ops level greater "
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"than your own"
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)
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