mirror of
https://mau.dev/maunium/synapse.git
synced 2024-10-01 01:36:05 -04:00
1246 lines
46 KiB
Python
1246 lines
46 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright 2014 - 2016 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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import logging
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import pymacaroons
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from canonicaljson import encode_canonical_json
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from signedjson.key import decode_verify_key_bytes
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from signedjson.sign import verify_signed_json, SignatureVerifyException
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from twisted.internet import defer
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from unpaddedbase64 import decode_base64
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import synapse.types
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from synapse.api.constants import EventTypes, Membership, JoinRules
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from synapse.api.errors import AuthError, Codes, SynapseError, EventSizeError
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from synapse.types import UserID, get_domain_from_id
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from synapse.util.logcontext import preserve_context_over_fn
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from synapse.util.logutils import log_function
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from synapse.util.metrics import Measure
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logger = logging.getLogger(__name__)
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AuthEventTypes = (
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EventTypes.Create, EventTypes.Member, EventTypes.PowerLevels,
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EventTypes.JoinRules, EventTypes.RoomHistoryVisibility,
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EventTypes.ThirdPartyInvite,
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)
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# guests always get this device id.
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GUEST_DEVICE_ID = "guest_device"
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class Auth(object):
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"""
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FIXME: This class contains a mix of functions for authenticating users
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of our client-server API and authenticating events added to room graphs.
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"""
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def __init__(self, hs):
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self.hs = hs
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self.clock = hs.get_clock()
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self.store = hs.get_datastore()
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self.state = hs.get_state_handler()
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self.TOKEN_NOT_FOUND_HTTP_STATUS = 401
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@defer.inlineCallbacks
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def check_from_context(self, event, context, do_sig_check=True):
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auth_events_ids = yield self.compute_auth_events(
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event, context.prev_state_ids, for_verification=True,
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)
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auth_events = yield self.store.get_events(auth_events_ids)
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auth_events = {
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(e.type, e.state_key): e for e in auth_events.values()
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}
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self.check(event, auth_events=auth_events, do_sig_check=do_sig_check)
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def check(self, event, auth_events, do_sig_check=True):
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""" Checks if this event is correctly authed.
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Args:
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event: the event being checked.
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auth_events (dict: event-key -> event): the existing room state.
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Returns:
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True if the auth checks pass.
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"""
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with Measure(self.clock, "auth.check"):
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self.check_size_limits(event)
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if not hasattr(event, "room_id"):
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raise AuthError(500, "Event has no room_id: %s" % event)
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if do_sig_check:
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sender_domain = get_domain_from_id(event.sender)
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event_id_domain = get_domain_from_id(event.event_id)
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is_invite_via_3pid = (
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event.type == EventTypes.Member
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and event.membership == Membership.INVITE
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and "third_party_invite" in event.content
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)
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# Check the sender's domain has signed the event
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if not event.signatures.get(sender_domain):
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# We allow invites via 3pid to have a sender from a different
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# HS, as the sender must match the sender of the original
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# 3pid invite. This is checked further down with the
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# other dedicated membership checks.
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if not is_invite_via_3pid:
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raise AuthError(403, "Event not signed by sender's server")
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# Check the event_id's domain has signed the event
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if not event.signatures.get(event_id_domain):
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raise AuthError(403, "Event not signed by sending server")
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if auth_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 event.type == EventTypes.Create:
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room_id_domain = get_domain_from_id(event.room_id)
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if room_id_domain != sender_domain:
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raise AuthError(
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403,
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"Creation event's room_id domain does not match sender's"
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)
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# FIXME
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return True
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creation_event = auth_events.get((EventTypes.Create, ""), None)
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if not creation_event:
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raise SynapseError(
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403,
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"Room %r does not exist" % (event.room_id,)
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)
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creating_domain = get_domain_from_id(event.room_id)
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originating_domain = get_domain_from_id(event.sender)
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if creating_domain != originating_domain:
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if not self.can_federate(event, auth_events):
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raise AuthError(
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403,
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"This room has been marked as unfederatable."
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)
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# FIXME: Temp hack
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if event.type == EventTypes.Aliases:
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if not event.is_state():
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raise AuthError(
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403,
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"Alias event must be a state event",
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)
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if not event.state_key:
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raise AuthError(
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403,
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"Alias event must have non-empty state_key"
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)
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sender_domain = get_domain_from_id(event.sender)
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if event.state_key != sender_domain:
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raise AuthError(
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403,
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"Alias event's state_key does not match sender's domain"
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)
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return True
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logger.debug(
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"Auth events: %s",
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[a.event_id for a in auth_events.values()]
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)
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if event.type == EventTypes.Member:
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allowed = self.is_membership_change_allowed(
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event, auth_events
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)
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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.check_event_sender_in_room(event, auth_events)
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# Special case to allow m.room.third_party_invite events wherever
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# a user is allowed to issue invites. Fixes
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# https://github.com/vector-im/vector-web/issues/1208 hopefully
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if event.type == EventTypes.ThirdPartyInvite:
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user_level = self._get_user_power_level(event.user_id, auth_events)
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invite_level = self._get_named_level(auth_events, "invite", 0)
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if user_level < invite_level:
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raise AuthError(
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403, (
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"You cannot issue a third party invite for %s." %
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(event.content.display_name,)
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)
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)
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else:
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return True
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self._can_send_event(event, auth_events)
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if event.type == EventTypes.PowerLevels:
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self._check_power_levels(event, auth_events)
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if event.type == EventTypes.Redaction:
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self.check_redaction(event, auth_events)
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logger.debug("Allowing! %s", event)
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def check_size_limits(self, event):
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def too_big(field):
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raise EventSizeError("%s too large" % (field,))
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if len(event.user_id) > 255:
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too_big("user_id")
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if len(event.room_id) > 255:
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too_big("room_id")
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if event.is_state() and len(event.state_key) > 255:
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too_big("state_key")
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if len(event.type) > 255:
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too_big("type")
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if len(event.event_id) > 255:
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too_big("event_id")
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if len(encode_canonical_json(event.get_pdu_json())) > 65536:
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too_big("event")
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@defer.inlineCallbacks
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def check_joined_room(self, room_id, user_id, current_state=None):
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"""Check if the user is currently joined in the room
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Args:
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room_id(str): The room to check.
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user_id(str): The user to check.
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current_state(dict): Optional map of the current state of the room.
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If provided then that map is used to check whether they are a
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member of the room. Otherwise the current membership is
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loaded from the database.
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Raises:
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AuthError if the user is not in the room.
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Returns:
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A deferred membership event for the user if the user is in
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the room.
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"""
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if current_state:
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member = current_state.get(
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(EventTypes.Member, user_id),
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None
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)
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else:
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member = yield self.state.get_current_state(
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room_id=room_id,
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event_type=EventTypes.Member,
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state_key=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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@defer.inlineCallbacks
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def check_user_was_in_room(self, room_id, user_id):
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"""Check if the user was in the room at some point.
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Args:
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room_id(str): The room to check.
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user_id(str): The user to check.
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Raises:
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AuthError if the user was never in the room.
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Returns:
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A deferred membership event for the user if the user was in the
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room. This will be the join event if they are currently joined to
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the room. This will be the leave event if they have left the room.
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"""
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member = yield self.state.get_current_state(
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room_id=room_id,
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event_type=EventTypes.Member,
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state_key=user_id
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)
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membership = member.membership if member else None
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if membership not in (Membership.JOIN, Membership.LEAVE):
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raise AuthError(403, "User %s not in room %s" % (
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user_id, room_id
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))
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if membership == Membership.LEAVE:
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forgot = yield self.store.did_forget(user_id, room_id)
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if forgot:
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raise AuthError(403, "User %s not in room %s" % (
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user_id, room_id
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))
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defer.returnValue(member)
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@defer.inlineCallbacks
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def check_host_in_room(self, room_id, host):
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with Measure(self.clock, "check_host_in_room"):
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latest_event_ids = yield self.store.get_latest_event_ids_in_room(room_id)
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logger.info("calling resolve_state_groups from check_host_in_room")
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entry = yield self.state.resolve_state_groups(
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room_id, latest_event_ids
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)
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ret = yield self.store.is_host_joined(
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room_id, host, entry.state_group, entry.state
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)
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defer.returnValue(ret)
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def check_event_sender_in_room(self, event, auth_events):
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key = (EventTypes.Member, event.user_id, )
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member_event = auth_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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def can_federate(self, event, auth_events):
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creation_event = auth_events.get((EventTypes.Create, ""))
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return creation_event.content.get("m.federate", True) is True
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@log_function
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def is_membership_change_allowed(self, event, auth_events):
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membership = event.content["membership"]
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# Check if this is the room creator joining:
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if len(event.prev_events) == 1 and Membership.JOIN == membership:
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# Get room creation event:
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key = (EventTypes.Create, "", )
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create = auth_events.get(key)
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if create and event.prev_events[0][0] == create.event_id:
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if create.content["creator"] == event.state_key:
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return True
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target_user_id = event.state_key
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creating_domain = get_domain_from_id(event.room_id)
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target_domain = get_domain_from_id(target_user_id)
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if creating_domain != target_domain:
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if not self.can_federate(event, auth_events):
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raise AuthError(
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403,
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"This room has been marked as unfederatable."
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)
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# get info about the caller
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key = (EventTypes.Member, event.user_id, )
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caller = auth_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 = (EventTypes.Member, target_user_id, )
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target = auth_events.get(key)
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target_in_room = target and target.membership == Membership.JOIN
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target_banned = target and target.membership == Membership.BAN
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key = (EventTypes.JoinRules, "", )
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join_rule_event = auth_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_user_power_level(event.user_id, auth_events)
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target_level = self._get_user_power_level(
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target_user_id, auth_events
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)
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# FIXME (erikj): What should we do here as the default?
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ban_level = self._get_named_level(auth_events, "ban", 50)
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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_banned": target_banned,
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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 and "third_party_invite" in event.content:
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if not self._verify_third_party_invite(event, auth_events):
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raise AuthError(403, "You are not invited to this room.")
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if target_banned:
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raise AuthError(
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403, "%s is banned from the room" % (target_user_id,)
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)
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return True
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if Membership.JOIN != membership:
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if (caller_invited
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and Membership.LEAVE == membership
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and target_user_id == event.user_id):
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return True
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if not caller_in_room: # caller isn't joined
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raise AuthError(
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403,
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"%s not in room %s." % (event.user_id, event.room_id,)
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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 target_banned:
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raise AuthError(
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403, "%s is banned from the room" % (target_user_id,)
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)
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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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else:
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invite_level = self._get_named_level(auth_events, "invite", 0)
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if user_level < invite_level:
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raise AuthError(
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403, "You cannot invite user %s." % target_user_id
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)
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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 target_banned:
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raise AuthError(403, "You are banned from this room")
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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 target_banned and user_level < ban_level:
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raise AuthError(
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403, "You cannot unban user &s." % (target_user_id,)
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)
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elif target_user_id != event.user_id:
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kick_level = self._get_named_level(auth_events, "kick", 50)
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if user_level < kick_level or user_level <= target_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 user_level < ban_level or user_level <= target_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 _verify_third_party_invite(self, event, auth_events):
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"""
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Validates that the invite event is authorized by a previous third-party invite.
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Checks that the public key, and keyserver, match those in the third party invite,
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and that the invite event has a signature issued using that public key.
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Args:
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event: The m.room.member join event being validated.
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auth_events: All relevant previous context events which may be used
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for authorization decisions.
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Return:
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True if the event fulfills the expectations of a previous third party
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invite event.
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"""
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if "third_party_invite" not in event.content:
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return False
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if "signed" not in event.content["third_party_invite"]:
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return False
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signed = event.content["third_party_invite"]["signed"]
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for key in {"mxid", "token"}:
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if key not in signed:
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return False
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token = signed["token"]
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invite_event = auth_events.get(
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(EventTypes.ThirdPartyInvite, token,)
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)
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if not invite_event:
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return False
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if invite_event.sender != event.sender:
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return False
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|
|
if event.user_id != invite_event.user_id:
|
|
return False
|
|
|
|
if signed["mxid"] != event.state_key:
|
|
return False
|
|
if signed["token"] != token:
|
|
return False
|
|
|
|
for public_key_object in self.get_public_keys(invite_event):
|
|
public_key = public_key_object["public_key"]
|
|
try:
|
|
for server, signature_block in signed["signatures"].items():
|
|
for key_name, encoded_signature in signature_block.items():
|
|
if not key_name.startswith("ed25519:"):
|
|
continue
|
|
verify_key = decode_verify_key_bytes(
|
|
key_name,
|
|
decode_base64(public_key)
|
|
)
|
|
verify_signed_json(signed, server, verify_key)
|
|
|
|
# We got the public key from the invite, so we know that the
|
|
# correct server signed the signed bundle.
|
|
# The caller is responsible for checking that the signing
|
|
# server has not revoked that public key.
|
|
return True
|
|
except (KeyError, SignatureVerifyException,):
|
|
continue
|
|
return False
|
|
|
|
def get_public_keys(self, invite_event):
|
|
public_keys = []
|
|
if "public_key" in invite_event.content:
|
|
o = {
|
|
"public_key": invite_event.content["public_key"],
|
|
}
|
|
if "key_validity_url" in invite_event.content:
|
|
o["key_validity_url"] = invite_event.content["key_validity_url"]
|
|
public_keys.append(o)
|
|
public_keys.extend(invite_event.content.get("public_keys", []))
|
|
return public_keys
|
|
|
|
def _get_power_level_event(self, auth_events):
|
|
key = (EventTypes.PowerLevels, "", )
|
|
return auth_events.get(key)
|
|
|
|
def _get_user_power_level(self, user_id, auth_events):
|
|
power_level_event = self._get_power_level_event(auth_events)
|
|
|
|
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)
|
|
|
|
if level is None:
|
|
return 0
|
|
else:
|
|
return int(level)
|
|
else:
|
|
key = (EventTypes.Create, "", )
|
|
create_event = auth_events.get(key)
|
|
if (create_event is not None and
|
|
create_event.content["creator"] == user_id):
|
|
return 100
|
|
else:
|
|
return 0
|
|
|
|
def _get_named_level(self, auth_events, name, default):
|
|
power_level_event = self._get_power_level_event(auth_events)
|
|
|
|
if not power_level_event:
|
|
return default
|
|
|
|
level = power_level_event.content.get(name, None)
|
|
if level is not None:
|
|
return int(level)
|
|
else:
|
|
return default
|
|
|
|
@defer.inlineCallbacks
|
|
def get_user_by_req(self, request, allow_guest=False, rights="access"):
|
|
""" Get a registered user's ID.
|
|
|
|
Args:
|
|
request - An HTTP request with an access_token query parameter.
|
|
Returns:
|
|
defer.Deferred: resolves to a ``synapse.types.Requester`` object
|
|
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:
|
|
user_id, app_service = yield self._get_appservice_user_id(request)
|
|
if user_id:
|
|
request.authenticated_entity = user_id
|
|
defer.returnValue(
|
|
synapse.types.create_requester(user_id, app_service=app_service)
|
|
)
|
|
|
|
access_token = get_access_token_from_request(
|
|
request, self.TOKEN_NOT_FOUND_HTTP_STATUS
|
|
)
|
|
|
|
user_info = yield self.get_user_by_access_token(access_token, rights)
|
|
user = user_info["user"]
|
|
token_id = user_info["token_id"]
|
|
is_guest = user_info["is_guest"]
|
|
|
|
# device_id may not be present if get_user_by_access_token has been
|
|
# stubbed out.
|
|
device_id = user_info.get("device_id")
|
|
|
|
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:
|
|
preserve_context_over_fn(
|
|
self.store.insert_client_ip,
|
|
user=user,
|
|
access_token=access_token,
|
|
ip=ip_addr,
|
|
user_agent=user_agent,
|
|
device_id=device_id,
|
|
)
|
|
|
|
if is_guest and not allow_guest:
|
|
raise AuthError(
|
|
403, "Guest access not allowed", errcode=Codes.GUEST_ACCESS_FORBIDDEN
|
|
)
|
|
|
|
request.authenticated_entity = user.to_string()
|
|
|
|
defer.returnValue(synapse.types.create_requester(
|
|
user, token_id, is_guest, device_id, app_service=app_service)
|
|
)
|
|
except KeyError:
|
|
raise AuthError(
|
|
self.TOKEN_NOT_FOUND_HTTP_STATUS, "Missing access token.",
|
|
errcode=Codes.MISSING_TOKEN
|
|
)
|
|
|
|
@defer.inlineCallbacks
|
|
def _get_appservice_user_id(self, request):
|
|
app_service = self.store.get_app_service_by_token(
|
|
get_access_token_from_request(
|
|
request, self.TOKEN_NOT_FOUND_HTTP_STATUS
|
|
)
|
|
)
|
|
if app_service is None:
|
|
defer.returnValue((None, None))
|
|
|
|
if "user_id" not in request.args:
|
|
defer.returnValue((app_service.sender, app_service))
|
|
|
|
user_id = request.args["user_id"][0]
|
|
if app_service.sender == user_id:
|
|
defer.returnValue((app_service.sender, app_service))
|
|
|
|
if not app_service.is_interested_in_user(user_id):
|
|
raise AuthError(
|
|
403,
|
|
"Application service cannot masquerade as this user."
|
|
)
|
|
if not (yield self.store.get_user_by_id(user_id)):
|
|
raise AuthError(
|
|
403,
|
|
"Application service has not registered this user"
|
|
)
|
|
defer.returnValue((user_id, app_service))
|
|
|
|
@defer.inlineCallbacks
|
|
def get_user_by_access_token(self, token, rights="access"):
|
|
""" Validate access token and get user_id from it
|
|
|
|
Args:
|
|
token (str): The access token to get the user by.
|
|
rights (str): The operation being performed; the access token must
|
|
allow this.
|
|
Returns:
|
|
dict : dict that includes the user and the ID of their access token.
|
|
Raises:
|
|
AuthError if no user by that token exists or the token is invalid.
|
|
"""
|
|
try:
|
|
macaroon = pymacaroons.Macaroon.deserialize(token)
|
|
except Exception: # deserialize can throw more-or-less anything
|
|
# doesn't look like a macaroon: treat it as an opaque token which
|
|
# must be in the database.
|
|
# TODO: it would be nice to get rid of this, but apparently some
|
|
# people use access tokens which aren't macaroons
|
|
r = yield self._look_up_user_by_access_token(token)
|
|
defer.returnValue(r)
|
|
|
|
try:
|
|
user_id = self.get_user_id_from_macaroon(macaroon)
|
|
user = UserID.from_string(user_id)
|
|
|
|
self.validate_macaroon(
|
|
macaroon, rights, self.hs.config.expire_access_token,
|
|
user_id=user_id,
|
|
)
|
|
|
|
guest = False
|
|
for caveat in macaroon.caveats:
|
|
if caveat.caveat_id == "guest = true":
|
|
guest = True
|
|
|
|
if guest:
|
|
# Guest access tokens are not stored in the database (there can
|
|
# only be one access token per guest, anyway).
|
|
#
|
|
# In order to prevent guest access tokens being used as regular
|
|
# user access tokens (and hence getting around the invalidation
|
|
# process), we look up the user id and check that it is indeed
|
|
# a guest user.
|
|
#
|
|
# It would of course be much easier to store guest access
|
|
# tokens in the database as well, but that would break existing
|
|
# guest tokens.
|
|
stored_user = yield self.store.get_user_by_id(user_id)
|
|
if not stored_user:
|
|
raise AuthError(
|
|
self.TOKEN_NOT_FOUND_HTTP_STATUS,
|
|
"Unknown user_id %s" % user_id,
|
|
errcode=Codes.UNKNOWN_TOKEN
|
|
)
|
|
if not stored_user["is_guest"]:
|
|
raise AuthError(
|
|
self.TOKEN_NOT_FOUND_HTTP_STATUS,
|
|
"Guest access token used for regular user",
|
|
errcode=Codes.UNKNOWN_TOKEN
|
|
)
|
|
ret = {
|
|
"user": user,
|
|
"is_guest": True,
|
|
"token_id": None,
|
|
# all guests get the same device id
|
|
"device_id": GUEST_DEVICE_ID,
|
|
}
|
|
elif rights == "delete_pusher":
|
|
# We don't store these tokens in the database
|
|
ret = {
|
|
"user": user,
|
|
"is_guest": False,
|
|
"token_id": None,
|
|
"device_id": None,
|
|
}
|
|
else:
|
|
# This codepath exists for several reasons:
|
|
# * so that we can actually return a token ID, which is used
|
|
# in some parts of the schema (where we probably ought to
|
|
# use device IDs instead)
|
|
# * the only way we currently have to invalidate an
|
|
# access_token is by removing it from the database, so we
|
|
# have to check here that it is still in the db
|
|
# * some attributes (notably device_id) aren't stored in the
|
|
# macaroon. They probably should be.
|
|
# TODO: build the dictionary from the macaroon once the
|
|
# above are fixed
|
|
ret = yield self._look_up_user_by_access_token(token)
|
|
if ret["user"] != user:
|
|
logger.error(
|
|
"Macaroon user (%s) != DB user (%s)",
|
|
user,
|
|
ret["user"]
|
|
)
|
|
raise AuthError(
|
|
self.TOKEN_NOT_FOUND_HTTP_STATUS,
|
|
"User mismatch in macaroon",
|
|
errcode=Codes.UNKNOWN_TOKEN
|
|
)
|
|
defer.returnValue(ret)
|
|
except (pymacaroons.exceptions.MacaroonException, TypeError, ValueError):
|
|
raise AuthError(
|
|
self.TOKEN_NOT_FOUND_HTTP_STATUS, "Invalid macaroon passed.",
|
|
errcode=Codes.UNKNOWN_TOKEN
|
|
)
|
|
|
|
def get_user_id_from_macaroon(self, macaroon):
|
|
"""Retrieve the user_id given by the caveats on the macaroon.
|
|
|
|
Does *not* validate the macaroon.
|
|
|
|
Args:
|
|
macaroon (pymacaroons.Macaroon): The macaroon to validate
|
|
|
|
Returns:
|
|
(str) user id
|
|
|
|
Raises:
|
|
AuthError if there is no user_id caveat in the macaroon
|
|
"""
|
|
user_prefix = "user_id = "
|
|
for caveat in macaroon.caveats:
|
|
if caveat.caveat_id.startswith(user_prefix):
|
|
return caveat.caveat_id[len(user_prefix):]
|
|
raise AuthError(
|
|
self.TOKEN_NOT_FOUND_HTTP_STATUS, "No user caveat in macaroon",
|
|
errcode=Codes.UNKNOWN_TOKEN
|
|
)
|
|
|
|
def validate_macaroon(self, macaroon, type_string, verify_expiry, user_id):
|
|
"""
|
|
validate that a Macaroon is understood by and was signed by this server.
|
|
|
|
Args:
|
|
macaroon(pymacaroons.Macaroon): The macaroon to validate
|
|
type_string(str): The kind of token required (e.g. "access",
|
|
"delete_pusher")
|
|
verify_expiry(bool): Whether to verify whether the macaroon has expired.
|
|
user_id (str): The user_id required
|
|
"""
|
|
v = pymacaroons.Verifier()
|
|
|
|
# the verifier runs a test for every caveat on the macaroon, to check
|
|
# that it is met for the current request. Each caveat must match at
|
|
# least one of the predicates specified by satisfy_exact or
|
|
# specify_general.
|
|
v.satisfy_exact("gen = 1")
|
|
v.satisfy_exact("type = " + type_string)
|
|
v.satisfy_exact("user_id = %s" % user_id)
|
|
v.satisfy_exact("guest = true")
|
|
|
|
# verify_expiry should really always be True, but there exist access
|
|
# tokens in the wild which expire when they should not, so we can't
|
|
# enforce expiry yet (so we have to allow any caveat starting with
|
|
# 'time < ' in access tokens).
|
|
#
|
|
# On the other hand, short-term login tokens (as used by CAS login, for
|
|
# example) have an expiry time which we do want to enforce.
|
|
|
|
if verify_expiry:
|
|
v.satisfy_general(self._verify_expiry)
|
|
else:
|
|
v.satisfy_general(lambda c: c.startswith("time < "))
|
|
|
|
# access_tokens include a nonce for uniqueness: any value is acceptable
|
|
v.satisfy_general(lambda c: c.startswith("nonce = "))
|
|
|
|
v.verify(macaroon, self.hs.config.macaroon_secret_key)
|
|
|
|
def _verify_expiry(self, caveat):
|
|
prefix = "time < "
|
|
if not caveat.startswith(prefix):
|
|
return False
|
|
expiry = int(caveat[len(prefix):])
|
|
now = self.hs.get_clock().time_msec()
|
|
return now < expiry
|
|
|
|
@defer.inlineCallbacks
|
|
def _look_up_user_by_access_token(self, token):
|
|
ret = yield self.store.get_user_by_access_token(token)
|
|
if not ret:
|
|
logger.warn("Unrecognised access token - not in store: %s" % (token,))
|
|
raise AuthError(
|
|
self.TOKEN_NOT_FOUND_HTTP_STATUS, "Unrecognised access token.",
|
|
errcode=Codes.UNKNOWN_TOKEN
|
|
)
|
|
# we use ret.get() below because *lots* of unit tests stub out
|
|
# get_user_by_access_token in a way where it only returns a couple of
|
|
# the fields.
|
|
user_info = {
|
|
"user": UserID.from_string(ret.get("name")),
|
|
"token_id": ret.get("token_id", None),
|
|
"is_guest": False,
|
|
"device_id": ret.get("device_id"),
|
|
}
|
|
defer.returnValue(user_info)
|
|
|
|
def get_appservice_by_req(self, request):
|
|
try:
|
|
token = get_access_token_from_request(
|
|
request, self.TOKEN_NOT_FOUND_HTTP_STATUS
|
|
)
|
|
service = self.store.get_app_service_by_token(token)
|
|
if not service:
|
|
logger.warn("Unrecognised appservice access token: %s" % (token,))
|
|
raise AuthError(
|
|
self.TOKEN_NOT_FOUND_HTTP_STATUS,
|
|
"Unrecognised access token.",
|
|
errcode=Codes.UNKNOWN_TOKEN
|
|
)
|
|
request.authenticated_entity = service.sender
|
|
return defer.succeed(service)
|
|
except KeyError:
|
|
raise AuthError(
|
|
self.TOKEN_NOT_FOUND_HTTP_STATUS, "Missing access token."
|
|
)
|
|
|
|
def is_server_admin(self, user):
|
|
return self.store.is_server_admin(user)
|
|
|
|
@defer.inlineCallbacks
|
|
def add_auth_events(self, builder, context):
|
|
auth_ids = yield self.compute_auth_events(builder, context.prev_state_ids)
|
|
|
|
auth_events_entries = yield self.store.add_event_hashes(
|
|
auth_ids
|
|
)
|
|
|
|
builder.auth_events = auth_events_entries
|
|
|
|
@defer.inlineCallbacks
|
|
def compute_auth_events(self, event, current_state_ids, for_verification=False):
|
|
if event.type == EventTypes.Create:
|
|
defer.returnValue([])
|
|
|
|
auth_ids = []
|
|
|
|
key = (EventTypes.PowerLevels, "", )
|
|
power_level_event_id = current_state_ids.get(key)
|
|
|
|
if power_level_event_id:
|
|
auth_ids.append(power_level_event_id)
|
|
|
|
key = (EventTypes.JoinRules, "", )
|
|
join_rule_event_id = current_state_ids.get(key)
|
|
|
|
key = (EventTypes.Member, event.user_id, )
|
|
member_event_id = current_state_ids.get(key)
|
|
|
|
key = (EventTypes.Create, "", )
|
|
create_event_id = current_state_ids.get(key)
|
|
if create_event_id:
|
|
auth_ids.append(create_event_id)
|
|
|
|
if join_rule_event_id:
|
|
join_rule_event = yield self.store.get_event(join_rule_event_id)
|
|
join_rule = join_rule_event.content.get("join_rule")
|
|
is_public = join_rule == JoinRules.PUBLIC if join_rule else False
|
|
else:
|
|
is_public = False
|
|
|
|
if event.type == EventTypes.Member:
|
|
e_type = event.content["membership"]
|
|
if e_type in [Membership.JOIN, Membership.INVITE]:
|
|
if join_rule_event_id:
|
|
auth_ids.append(join_rule_event_id)
|
|
|
|
if e_type == Membership.JOIN:
|
|
if member_event_id and not is_public:
|
|
auth_ids.append(member_event_id)
|
|
else:
|
|
if member_event_id:
|
|
auth_ids.append(member_event_id)
|
|
|
|
if for_verification:
|
|
key = (EventTypes.Member, event.state_key, )
|
|
existing_event_id = current_state_ids.get(key)
|
|
if existing_event_id:
|
|
auth_ids.append(existing_event_id)
|
|
|
|
if e_type == Membership.INVITE:
|
|
if "third_party_invite" in event.content:
|
|
key = (
|
|
EventTypes.ThirdPartyInvite,
|
|
event.content["third_party_invite"]["signed"]["token"]
|
|
)
|
|
third_party_invite_id = current_state_ids.get(key)
|
|
if third_party_invite_id:
|
|
auth_ids.append(third_party_invite_id)
|
|
elif member_event_id:
|
|
member_event = yield self.store.get_event(member_event_id)
|
|
if member_event.content["membership"] == Membership.JOIN:
|
|
auth_ids.append(member_event.event_id)
|
|
|
|
defer.returnValue(auth_ids)
|
|
|
|
def _get_send_level(self, etype, state_key, auth_events):
|
|
key = (EventTypes.PowerLevels, "", )
|
|
send_level_event = auth_events.get(key)
|
|
send_level = None
|
|
if send_level_event:
|
|
send_level = send_level_event.content.get("events", {}).get(
|
|
etype
|
|
)
|
|
if send_level is None:
|
|
if state_key is not None:
|
|
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
|
|
|
|
return send_level
|
|
|
|
@log_function
|
|
def _can_send_event(self, event, auth_events):
|
|
send_level = self._get_send_level(
|
|
event.type, event.get("state_key", None), auth_events
|
|
)
|
|
user_level = self._get_user_power_level(event.user_id, auth_events)
|
|
|
|
if user_level < send_level:
|
|
raise AuthError(
|
|
403,
|
|
"You don't have permission to post that to the room. " +
|
|
"user_level (%d) < send_level (%d)" % (user_level, send_level)
|
|
)
|
|
|
|
# Check state_key
|
|
if hasattr(event, "state_key"):
|
|
if event.state_key.startswith("@"):
|
|
if event.state_key != event.user_id:
|
|
raise AuthError(
|
|
403,
|
|
"You are not allowed to set others state"
|
|
)
|
|
|
|
return True
|
|
|
|
def check_redaction(self, event, auth_events):
|
|
"""Check whether the event sender is allowed to redact the target event.
|
|
|
|
Returns:
|
|
True if the the sender is allowed to redact the target event if the
|
|
target event was created by them.
|
|
False if the sender is allowed to redact the target event with no
|
|
further checks.
|
|
|
|
Raises:
|
|
AuthError if the event sender is definitely not allowed to redact
|
|
the target event.
|
|
"""
|
|
user_level = self._get_user_power_level(event.user_id, auth_events)
|
|
|
|
redact_level = self._get_named_level(auth_events, "redact", 50)
|
|
|
|
if user_level >= redact_level:
|
|
return False
|
|
|
|
redacter_domain = get_domain_from_id(event.event_id)
|
|
redactee_domain = get_domain_from_id(event.redacts)
|
|
if redacter_domain == redactee_domain:
|
|
return True
|
|
|
|
raise AuthError(
|
|
403,
|
|
"You don't have permission to redact events"
|
|
)
|
|
|
|
def _check_power_levels(self, event, auth_events):
|
|
user_list = event.content.get("users", {})
|
|
# Validate users
|
|
for k, v in user_list.items():
|
|
try:
|
|
UserID.from_string(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 = auth_events.get(key)
|
|
|
|
if not current_state:
|
|
return
|
|
|
|
user_level = self._get_user_power_level(event.user_id, auth_events)
|
|
|
|
# Check other levels:
|
|
levels_to_check = [
|
|
("users_default", None),
|
|
("events_default", None),
|
|
("state_default", None),
|
|
("ban", None),
|
|
("redact", None),
|
|
("kick", None),
|
|
("invite", None),
|
|
]
|
|
|
|
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
|
|
new_loc = new_state
|
|
if dir:
|
|
old_loc = old_loc.get(dir, {})
|
|
new_loc = new_loc.get(dir, {})
|
|
|
|
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 dir == "users" and level_to_check != event.user_id:
|
|
if old_level == user_level:
|
|
raise AuthError(
|
|
403,
|
|
"You don't have permission to remove ops level equal "
|
|
"to your own"
|
|
)
|
|
|
|
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"
|
|
)
|
|
|
|
@defer.inlineCallbacks
|
|
def check_can_change_room_list(self, room_id, user):
|
|
"""Check if the user is allowed to edit the room's entry in the
|
|
published room list.
|
|
|
|
Args:
|
|
room_id (str)
|
|
user (UserID)
|
|
"""
|
|
|
|
is_admin = yield self.is_server_admin(user)
|
|
if is_admin:
|
|
defer.returnValue(True)
|
|
|
|
user_id = user.to_string()
|
|
yield self.check_joined_room(room_id, user_id)
|
|
|
|
# We currently require the user is a "moderator" in the room. We do this
|
|
# by checking if they would (theoretically) be able to change the
|
|
# m.room.aliases events
|
|
power_level_event = yield self.state.get_current_state(
|
|
room_id, EventTypes.PowerLevels, ""
|
|
)
|
|
|
|
auth_events = {}
|
|
if power_level_event:
|
|
auth_events[(EventTypes.PowerLevels, "")] = power_level_event
|
|
|
|
send_level = self._get_send_level(
|
|
EventTypes.Aliases, "", auth_events
|
|
)
|
|
user_level = self._get_user_power_level(user_id, auth_events)
|
|
|
|
if user_level < send_level:
|
|
raise AuthError(
|
|
403,
|
|
"This server requires you to be a moderator in the room to"
|
|
" edit its room list entry"
|
|
)
|
|
|
|
|
|
def has_access_token(request):
|
|
"""Checks if the request has an access_token.
|
|
|
|
Returns:
|
|
bool: False if no access_token was given, True otherwise.
|
|
"""
|
|
query_params = request.args.get("access_token")
|
|
auth_headers = request.requestHeaders.getRawHeaders("Authorization")
|
|
return bool(query_params) or bool(auth_headers)
|
|
|
|
|
|
def get_access_token_from_request(request, token_not_found_http_status=401):
|
|
"""Extracts the access_token from the request.
|
|
|
|
Args:
|
|
request: The http request.
|
|
token_not_found_http_status(int): The HTTP status code to set in the
|
|
AuthError if the token isn't found. This is used in some of the
|
|
legacy APIs to change the status code to 403 from the default of
|
|
401 since some of the old clients depended on auth errors returning
|
|
403.
|
|
Returns:
|
|
str: The access_token
|
|
Raises:
|
|
AuthError: If there isn't an access_token in the request.
|
|
"""
|
|
|
|
auth_headers = request.requestHeaders.getRawHeaders("Authorization")
|
|
query_params = request.args.get("access_token")
|
|
if auth_headers:
|
|
# Try the get the access_token from a "Authorization: Bearer"
|
|
# header
|
|
if query_params is not None:
|
|
raise AuthError(
|
|
token_not_found_http_status,
|
|
"Mixing Authorization headers and access_token query parameters.",
|
|
errcode=Codes.MISSING_TOKEN,
|
|
)
|
|
if len(auth_headers) > 1:
|
|
raise AuthError(
|
|
token_not_found_http_status,
|
|
"Too many Authorization headers.",
|
|
errcode=Codes.MISSING_TOKEN,
|
|
)
|
|
parts = auth_headers[0].split(" ")
|
|
if parts[0] == "Bearer" and len(parts) == 2:
|
|
return parts[1]
|
|
else:
|
|
raise AuthError(
|
|
token_not_found_http_status,
|
|
"Invalid Authorization header.",
|
|
errcode=Codes.MISSING_TOKEN,
|
|
)
|
|
else:
|
|
# Try to get the access_token from the query params.
|
|
if not query_params:
|
|
raise AuthError(
|
|
token_not_found_http_status,
|
|
"Missing access token.",
|
|
errcode=Codes.MISSING_TOKEN
|
|
)
|
|
|
|
return query_params[0]
|