603 lines
23 KiB
Python
603 lines
23 KiB
Python
# 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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from typing import TYPE_CHECKING, Optional, Tuple
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import pymacaroons
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from netaddr import IPAddress
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from twisted.web.server import Request
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from synapse import event_auth
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from synapse.api.constants import EventTypes, HistoryVisibility, Membership
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from synapse.api.errors import (
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AuthError,
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Codes,
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InvalidClientTokenError,
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MissingClientTokenError,
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UnstableSpecAuthError,
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)
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from synapse.appservice import ApplicationService
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from synapse.http import get_request_user_agent
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from synapse.http.site import SynapseRequest
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from synapse.logging.opentracing import (
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active_span,
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force_tracing,
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start_active_span,
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trace,
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)
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from synapse.types import Requester, create_requester
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from synapse.util.cancellation import cancellable
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if TYPE_CHECKING:
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from synapse.server import HomeServer
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logger = logging.getLogger(__name__)
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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:
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"""
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This class contains functions for authenticating users of our client-server API.
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"""
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def __init__(self, hs: "HomeServer"):
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self.hs = hs
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self.clock = hs.get_clock()
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self.store = hs.get_datastores().main
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self._account_validity_handler = hs.get_account_validity_handler()
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self._storage_controllers = hs.get_storage_controllers()
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self._macaroon_generator = hs.get_macaroon_generator()
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self._track_appservice_user_ips = hs.config.appservice.track_appservice_user_ips
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self._track_puppeted_user_ips = hs.config.api.track_puppeted_user_ips
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self._force_tracing_for_users = hs.config.tracing.force_tracing_for_users
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async def check_user_in_room(
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self,
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room_id: str,
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requester: Requester,
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allow_departed_users: bool = False,
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) -> Tuple[str, Optional[str]]:
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"""Check if the user is in the room, or was at some point.
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Args:
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room_id: The room to check.
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requester: The user making the request, according to the access token.
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current_state: 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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allow_departed_users: if True, accept users that were previously
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members but have now departed.
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Raises:
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AuthError if the user is/was not in the room.
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Returns:
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The current membership of the user in the room and the
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membership event ID of the user.
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"""
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user_id = requester.user.to_string()
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(
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membership,
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member_event_id,
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) = await self.store.get_local_current_membership_for_user_in_room(
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user_id=user_id,
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room_id=room_id,
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)
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if membership:
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if membership == Membership.JOIN:
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return membership, member_event_id
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# XXX this looks totally bogus. Why do we not allow users who have been banned,
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# or those who were members previously and have been re-invited?
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if allow_departed_users and membership == Membership.LEAVE:
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forgot = await self.store.did_forget(user_id, room_id)
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if not forgot:
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return membership, member_event_id
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raise UnstableSpecAuthError(
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403,
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"User %s not in room %s" % (user_id, room_id),
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errcode=Codes.NOT_JOINED,
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)
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@cancellable
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async def get_user_by_req(
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self,
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request: SynapseRequest,
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allow_guest: bool = False,
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allow_expired: bool = False,
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) -> Requester:
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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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allow_guest: If False, will raise an AuthError if the user making the
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request is a guest.
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allow_expired: If True, allow the request through even if the account
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is expired, or session token lifetime has ended. Note that
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/login will deliver access tokens regardless of expiration.
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Returns:
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Resolves to the requester
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Raises:
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InvalidClientCredentialsError if no user by that token exists or the token
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is invalid.
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AuthError if access is denied for the user in the access token
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"""
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parent_span = active_span()
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with start_active_span("get_user_by_req"):
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requester = await self._wrapped_get_user_by_req(
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request, allow_guest, allow_expired
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)
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if parent_span:
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if requester.authenticated_entity in self._force_tracing_for_users:
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# request tracing is enabled for this user, so we need to force it
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# tracing on for the parent span (which will be the servlet span).
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#
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# It's too late for the get_user_by_req span to inherit the setting,
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# so we also force it on for that.
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force_tracing()
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force_tracing(parent_span)
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parent_span.set_tag(
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"authenticated_entity", requester.authenticated_entity
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)
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parent_span.set_tag("user_id", requester.user.to_string())
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if requester.device_id is not None:
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parent_span.set_tag("device_id", requester.device_id)
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if requester.app_service is not None:
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parent_span.set_tag("appservice_id", requester.app_service.id)
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return requester
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@cancellable
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async def _wrapped_get_user_by_req(
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self,
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request: SynapseRequest,
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allow_guest: bool,
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allow_expired: bool,
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) -> Requester:
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"""Helper for get_user_by_req
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Once get_user_by_req has set up the opentracing span, this does the actual work.
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"""
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try:
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ip_addr = request.getClientAddress().host
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user_agent = get_request_user_agent(request)
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access_token = self.get_access_token_from_request(request)
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# First check if it could be a request from an appservice
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requester = await self._get_appservice_user(request)
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if not requester:
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# If not, it should be from a regular user
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requester = await self.get_user_by_access_token(
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access_token, allow_expired=allow_expired
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)
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# Deny the request if the user account has expired.
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# This check is only done for regular users, not appservice ones.
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if not allow_expired:
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if await self._account_validity_handler.is_user_expired(
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requester.user.to_string()
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):
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# Raise the error if either an account validity module has determined
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# the account has expired, or the legacy account validity
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# implementation is enabled and determined the account has expired
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raise AuthError(
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403,
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"User account has expired",
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errcode=Codes.EXPIRED_ACCOUNT,
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)
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if ip_addr and (
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not requester.app_service or self._track_appservice_user_ips
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):
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# XXX(quenting): I'm 95% confident that we could skip setting the
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# device_id to "dummy-device" for appservices, and that the only impact
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# would be some rows which whould not deduplicate in the 'user_ips'
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# table during the transition
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recorded_device_id = (
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"dummy-device"
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if requester.device_id is None and requester.app_service is not None
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else requester.device_id
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)
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await self.store.insert_client_ip(
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user_id=requester.authenticated_entity,
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access_token=access_token,
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ip=ip_addr,
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user_agent=user_agent,
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device_id=recorded_device_id,
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)
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# Track also the puppeted user client IP if enabled and the user is puppeting
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if (
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requester.user.to_string() != requester.authenticated_entity
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and self._track_puppeted_user_ips
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):
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await self.store.insert_client_ip(
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user_id=requester.user.to_string(),
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access_token=access_token,
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ip=ip_addr,
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user_agent=user_agent,
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device_id=requester.device_id,
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)
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if requester.is_guest and not allow_guest:
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raise AuthError(
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403,
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"Guest access not allowed",
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errcode=Codes.GUEST_ACCESS_FORBIDDEN,
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)
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request.requester = requester
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return requester
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except KeyError:
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raise MissingClientTokenError()
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async def validate_appservice_can_control_user_id(
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self, app_service: ApplicationService, user_id: str
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) -> None:
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"""Validates that the app service is allowed to control
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the given user.
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Args:
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app_service: The app service that controls the user
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user_id: The author MXID that the app service is controlling
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Raises:
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AuthError: If the application service is not allowed to control the user
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(user namespace regex does not match, wrong homeserver, etc)
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or if the user has not been registered yet.
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"""
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# It's ok if the app service is trying to use the sender from their registration
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if app_service.sender == user_id:
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pass
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# Check to make sure the app service is allowed to control the user
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elif not app_service.is_interested_in_user(user_id):
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raise AuthError(
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403,
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"Application service cannot masquerade as this user (%s)." % user_id,
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)
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# Check to make sure the user is already registered on the homeserver
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elif not (await self.store.get_user_by_id(user_id)):
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raise AuthError(
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403, "Application service has not registered this user (%s)" % user_id
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)
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@cancellable
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async def _get_appservice_user(self, request: Request) -> Optional[Requester]:
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"""
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Given a request, reads the request parameters to determine:
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- whether it's an application service that's making this request
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- what user the application service should be treated as controlling
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(the user_id URI parameter allows an application service to masquerade
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any applicable user in its namespace)
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- what device the application service should be treated as controlling
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(the device_id[^1] URI parameter allows an application service to masquerade
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as any device that exists for the relevant user)
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[^1] Unstable and provided by MSC3202.
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Must use `org.matrix.msc3202.device_id` in place of `device_id` for now.
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Returns:
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the application service `Requester` of that request
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Postconditions:
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- The `app_service` field in the returned `Requester` is set
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- The `user_id` field in the returned `Requester` is either the application
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service sender or the controlled user set by the `user_id` URI parameter
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- The returned application service is permitted to control the returned user ID.
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- The returned device ID, if present, has been checked to be a valid device ID
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for the returned user ID.
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"""
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DEVICE_ID_ARG_NAME = b"org.matrix.msc3202.device_id"
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app_service = self.store.get_app_service_by_token(
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self.get_access_token_from_request(request)
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)
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if app_service is None:
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return None
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if app_service.ip_range_whitelist:
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ip_address = IPAddress(request.getClientAddress().host)
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if ip_address not in app_service.ip_range_whitelist:
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return None
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# This will always be set by the time Twisted calls us.
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assert request.args is not None
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if b"user_id" in request.args:
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effective_user_id = request.args[b"user_id"][0].decode("utf8")
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await self.validate_appservice_can_control_user_id(
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app_service, effective_user_id
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)
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else:
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effective_user_id = app_service.sender
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effective_device_id: Optional[str] = None
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if (
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self.hs.config.experimental.msc3202_device_masquerading_enabled
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and DEVICE_ID_ARG_NAME in request.args
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):
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effective_device_id = request.args[DEVICE_ID_ARG_NAME][0].decode("utf8")
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# We only just set this so it can't be None!
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assert effective_device_id is not None
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device_opt = await self.store.get_device(
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effective_user_id, effective_device_id
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)
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if device_opt is None:
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# For now, use 400 M_EXCLUSIVE if the device doesn't exist.
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# This is an open thread of discussion on MSC3202 as of 2021-12-09.
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raise AuthError(
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400,
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f"Application service trying to use a device that doesn't exist ('{effective_device_id}' for {effective_user_id})",
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Codes.EXCLUSIVE,
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)
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return create_requester(
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effective_user_id, app_service=app_service, device_id=effective_device_id
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)
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async def get_user_by_access_token(
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self,
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token: str,
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allow_expired: bool = False,
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) -> Requester:
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"""Validate access token and get user_id from it
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Args:
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token: The access token to get the user by
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allow_expired: If False, raises an InvalidClientTokenError
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if the token is expired
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Raises:
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InvalidClientTokenError if a user by that token exists, but the token is
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expired
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InvalidClientCredentialsError if no user by that token exists or the token
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is invalid
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"""
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# First look in the database to see if the access token is present
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# as an opaque token.
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user_info = await self.store.get_user_by_access_token(token)
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if user_info:
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valid_until_ms = user_info.valid_until_ms
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if (
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not allow_expired
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and valid_until_ms is not None
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and valid_until_ms < self.clock.time_msec()
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):
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# there was a valid access token, but it has expired.
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# soft-logout the user.
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raise InvalidClientTokenError(
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msg="Access token has expired", soft_logout=True
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)
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# Mark the token as used. This is used to invalidate old refresh
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# tokens after some time.
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await self.store.mark_access_token_as_used(user_info.token_id)
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requester = create_requester(
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user_id=user_info.user_id,
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access_token_id=user_info.token_id,
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is_guest=user_info.is_guest,
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shadow_banned=user_info.shadow_banned,
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device_id=user_info.device_id,
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authenticated_entity=user_info.token_owner,
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)
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return requester
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# If the token isn't found in the database, then it could still be a
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# macaroon for a guest, so we check that here.
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try:
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user_id = self._macaroon_generator.verify_guest_token(token)
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# Guest access tokens are not stored in the database (there can
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# only be one access token per guest, anyway).
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#
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# In order to prevent guest access tokens being used as regular
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# user access tokens (and hence getting around the invalidation
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# process), we look up the user id and check that it is indeed
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# a guest user.
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#
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# It would of course be much easier to store guest access
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# tokens in the database as well, but that would break existing
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# guest tokens.
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stored_user = await self.store.get_user_by_id(user_id)
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if not stored_user:
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raise InvalidClientTokenError("Unknown user_id %s" % user_id)
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if not stored_user["is_guest"]:
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raise InvalidClientTokenError(
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"Guest access token used for regular user"
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)
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return create_requester(
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user_id=user_id,
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is_guest=True,
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# all guests get the same device id
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device_id=GUEST_DEVICE_ID,
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authenticated_entity=user_id,
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)
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except (
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pymacaroons.exceptions.MacaroonException,
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TypeError,
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ValueError,
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) as e:
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logger.warning(
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"Invalid access token in auth: %s %s.",
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type(e),
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e,
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)
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raise InvalidClientTokenError("Invalid access token passed.")
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async def is_server_admin(self, requester: Requester) -> bool:
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"""Check if the given user is a local server admin.
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Args:
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requester: The user making the request, according to the access token.
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Returns:
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True if the user is an admin
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"""
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return await self.store.is_server_admin(requester.user)
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async def check_can_change_room_list(
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self, room_id: str, requester: Requester
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) -> bool:
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"""Determine whether the user is allowed to edit the room's entry in the
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published room list.
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Args:
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room_id: The room to check.
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requester: The user making the request, according to the access token.
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"""
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is_admin = await self.is_server_admin(requester)
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if is_admin:
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return True
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await self.check_user_in_room(room_id, requester)
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# We currently require the user is a "moderator" in the room. We do this
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# by checking if they would (theoretically) be able to change the
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# m.room.canonical_alias events
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power_level_event = (
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await self._storage_controllers.state.get_current_state_event(
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room_id, EventTypes.PowerLevels, ""
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)
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)
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auth_events = {}
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if power_level_event:
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auth_events[(EventTypes.PowerLevels, "")] = power_level_event
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send_level = event_auth.get_send_level(
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EventTypes.CanonicalAlias, "", power_level_event
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)
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user_level = event_auth.get_user_power_level(
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requester.user.to_string(), auth_events
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)
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return user_level >= send_level
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@staticmethod
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def has_access_token(request: Request) -> bool:
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"""Checks if the request has an access_token.
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Returns:
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False if no access_token was given, True otherwise.
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"""
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# This will always be set by the time Twisted calls us.
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|
assert request.args is not None
|
|
|
|
query_params = request.args.get(b"access_token")
|
|
auth_headers = request.requestHeaders.getRawHeaders(b"Authorization")
|
|
return bool(query_params) or bool(auth_headers)
|
|
|
|
@staticmethod
|
|
@cancellable
|
|
def get_access_token_from_request(request: Request) -> str:
|
|
"""Extracts the access_token from the request.
|
|
|
|
Args:
|
|
request: The http request.
|
|
Returns:
|
|
The access_token
|
|
Raises:
|
|
MissingClientTokenError: If there isn't a single access_token in the
|
|
request
|
|
"""
|
|
# This will always be set by the time Twisted calls us.
|
|
assert request.args is not None
|
|
|
|
auth_headers = request.requestHeaders.getRawHeaders(b"Authorization")
|
|
query_params = request.args.get(b"access_token")
|
|
if auth_headers:
|
|
# Try the get the access_token from a "Authorization: Bearer"
|
|
# header
|
|
if query_params is not None:
|
|
raise MissingClientTokenError(
|
|
"Mixing Authorization headers and access_token query parameters."
|
|
)
|
|
if len(auth_headers) > 1:
|
|
raise MissingClientTokenError("Too many Authorization headers.")
|
|
parts = auth_headers[0].split(b" ")
|
|
if parts[0] == b"Bearer" and len(parts) == 2:
|
|
return parts[1].decode("ascii")
|
|
else:
|
|
raise MissingClientTokenError("Invalid Authorization header.")
|
|
else:
|
|
# Try to get the access_token from the query params.
|
|
if not query_params:
|
|
raise MissingClientTokenError()
|
|
|
|
return query_params[0].decode("ascii")
|
|
|
|
@trace
|
|
async def check_user_in_room_or_world_readable(
|
|
self, room_id: str, requester: Requester, allow_departed_users: bool = False
|
|
) -> Tuple[str, Optional[str]]:
|
|
"""Checks that the user is or was in the room or the room is world
|
|
readable. If it isn't then an exception is raised.
|
|
|
|
Args:
|
|
room_id: The room to check.
|
|
requester: The user making the request, according to the access token.
|
|
allow_departed_users: If True, accept users that were previously
|
|
members but have now departed.
|
|
|
|
Returns:
|
|
Resolves to the current membership of the user in the room and the
|
|
membership event ID of the user. If the user is not in the room and
|
|
never has been, then `(Membership.JOIN, None)` is returned.
|
|
"""
|
|
|
|
try:
|
|
# check_user_in_room will return the most recent membership
|
|
# event for the user if:
|
|
# * The user is a non-guest user, and was ever in the room
|
|
# * The user is a guest user, and has joined the room
|
|
# else it will throw.
|
|
return await self.check_user_in_room(
|
|
room_id, requester, allow_departed_users=allow_departed_users
|
|
)
|
|
except AuthError:
|
|
visibility = await self._storage_controllers.state.get_current_state_event(
|
|
room_id, EventTypes.RoomHistoryVisibility, ""
|
|
)
|
|
if (
|
|
visibility
|
|
and visibility.content.get("history_visibility")
|
|
== HistoryVisibility.WORLD_READABLE
|
|
):
|
|
return Membership.JOIN, None
|
|
raise UnstableSpecAuthError(
|
|
403,
|
|
"User %s not in room %s, and room previews are disabled"
|
|
% (requester.user, room_id),
|
|
errcode=Codes.NOT_JOINED,
|
|
)
|