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Diffstat (limited to 'synapse/api/auth/internal.py')
| -rw-r--r-- | synapse/api/auth/internal.py | 369 |
1 files changed, 369 insertions, 0 deletions
diff --git a/synapse/api/auth/internal.py b/synapse/api/auth/internal.py new file mode 100644 index 0000000000..813d537e53 --- /dev/null +++ b/synapse/api/auth/internal.py @@ -0,0 +1,369 @@ +# Copyright 2023 The Matrix.org Foundation. +# +# Licensed under the Apache License, Version 2.0 (the "License"); +# you may not use this file except in compliance with the License. +# You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, software +# distributed under the License is distributed on an "AS IS" BASIS, +# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +# See the License for the specific language governing permissions and +# limitations under the License. +import logging +from typing import TYPE_CHECKING, Optional + +import pymacaroons +from netaddr import IPAddress + +from twisted.web.server import Request + +from synapse.api.errors import ( + AuthError, + Codes, + InvalidClientTokenError, + MissingClientTokenError, +) +from synapse.http import get_request_user_agent +from synapse.http.site import SynapseRequest +from synapse.logging.opentracing import active_span, force_tracing, start_active_span +from synapse.types import Requester, create_requester +from synapse.util.cancellation import cancellable + +from . import GUEST_DEVICE_ID +from .base import BaseAuth + +if TYPE_CHECKING: + from synapse.server import HomeServer + +logger = logging.getLogger(__name__) + + +class InternalAuth(BaseAuth): + """ + This class contains functions for authenticating users of our client-server API. + """ + + def __init__(self, hs: "HomeServer"): + super().__init__(hs) + self.clock = hs.get_clock() + self._account_validity_handler = hs.get_account_validity_handler() + self._macaroon_generator = hs.get_macaroon_generator() + + self._track_appservice_user_ips = hs.config.appservice.track_appservice_user_ips + self._track_puppeted_user_ips = hs.config.api.track_puppeted_user_ips + self._force_tracing_for_users = hs.config.tracing.force_tracing_for_users + + @cancellable + async def get_user_by_req( + self, + request: SynapseRequest, + allow_guest: bool = False, + allow_expired: bool = False, + ) -> Requester: + """Get a registered user's ID. + + Args: + request: An HTTP request with an access_token query parameter. + allow_guest: If False, will raise an AuthError if the user making the + request is a guest. + allow_expired: If True, allow the request through even if the account + is expired, or session token lifetime has ended. Note that + /login will deliver access tokens regardless of expiration. + + Returns: + Resolves to the requester + Raises: + InvalidClientCredentialsError if no user by that token exists or the token + is invalid. + AuthError if access is denied for the user in the access token + """ + parent_span = active_span() + with start_active_span("get_user_by_req"): + requester = await self._wrapped_get_user_by_req( + request, allow_guest, allow_expired + ) + + if parent_span: + if requester.authenticated_entity in self._force_tracing_for_users: + # request tracing is enabled for this user, so we need to force it + # tracing on for the parent span (which will be the servlet span). + # + # It's too late for the get_user_by_req span to inherit the setting, + # so we also force it on for that. + force_tracing() + force_tracing(parent_span) + parent_span.set_tag( + "authenticated_entity", requester.authenticated_entity + ) + parent_span.set_tag("user_id", requester.user.to_string()) + if requester.device_id is not None: + parent_span.set_tag("device_id", requester.device_id) + if requester.app_service is not None: + parent_span.set_tag("appservice_id", requester.app_service.id) + return requester + + @cancellable + async def _wrapped_get_user_by_req( + self, + request: SynapseRequest, + allow_guest: bool, + allow_expired: bool, + ) -> Requester: + """Helper for get_user_by_req + + Once get_user_by_req has set up the opentracing span, this does the actual work. + """ + try: + ip_addr = request.getClientAddress().host + user_agent = get_request_user_agent(request) + + access_token = self.get_access_token_from_request(request) + + # First check if it could be a request from an appservice + requester = await self._get_appservice_user(request) + if not requester: + # If not, it should be from a regular user + requester = await self.get_user_by_access_token( + access_token, allow_expired=allow_expired + ) + + # Deny the request if the user account has expired. + # This check is only done for regular users, not appservice ones. + if not allow_expired: + if await self._account_validity_handler.is_user_expired( + requester.user.to_string() + ): + # Raise the error if either an account validity module has determined + # the account has expired, or the legacy account validity + # implementation is enabled and determined the account has expired + raise AuthError( + 403, + "User account has expired", + errcode=Codes.EXPIRED_ACCOUNT, + ) + + if ip_addr and ( + not requester.app_service or self._track_appservice_user_ips + ): + # XXX(quenting): I'm 95% confident that we could skip setting the + # device_id to "dummy-device" for appservices, and that the only impact + # would be some rows which whould not deduplicate in the 'user_ips' + # table during the transition + recorded_device_id = ( + "dummy-device" + if requester.device_id is None and requester.app_service is not None + else requester.device_id + ) + await self.store.insert_client_ip( + user_id=requester.authenticated_entity, + access_token=access_token, + ip=ip_addr, + user_agent=user_agent, + device_id=recorded_device_id, + ) + + # Track also the puppeted user client IP if enabled and the user is puppeting + if ( + requester.user.to_string() != requester.authenticated_entity + and self._track_puppeted_user_ips + ): + await self.store.insert_client_ip( + user_id=requester.user.to_string(), + access_token=access_token, + ip=ip_addr, + user_agent=user_agent, + device_id=requester.device_id, + ) + + if requester.is_guest and not allow_guest: + raise AuthError( + 403, + "Guest access not allowed", + errcode=Codes.GUEST_ACCESS_FORBIDDEN, + ) + + request.requester = requester + return requester + except KeyError: + raise MissingClientTokenError() + + @cancellable + async def _get_appservice_user(self, request: Request) -> Optional[Requester]: + """ + Given a request, reads the request parameters to determine: + - whether it's an application service that's making this request + - what user the application service should be treated as controlling + (the user_id URI parameter allows an application service to masquerade + any applicable user in its namespace) + - what device the application service should be treated as controlling + (the device_id[^1] URI parameter allows an application service to masquerade + as any device that exists for the relevant user) + + [^1] Unstable and provided by MSC3202. + Must use `org.matrix.msc3202.device_id` in place of `device_id` for now. + + Returns: + the application service `Requester` of that request + + Postconditions: + - The `app_service` field in the returned `Requester` is set + - The `user_id` field in the returned `Requester` is either the application + service sender or the controlled user set by the `user_id` URI parameter + - The returned application service is permitted to control the returned user ID. + - The returned device ID, if present, has been checked to be a valid device ID + for the returned user ID. + """ + DEVICE_ID_ARG_NAME = b"org.matrix.msc3202.device_id" + + app_service = self.store.get_app_service_by_token( + self.get_access_token_from_request(request) + ) + if app_service is None: + return None + + if app_service.ip_range_whitelist: + ip_address = IPAddress(request.getClientAddress().host) + if ip_address not in app_service.ip_range_whitelist: + return None + + # This will always be set by the time Twisted calls us. + assert request.args is not None + + if b"user_id" in request.args: + effective_user_id = request.args[b"user_id"][0].decode("utf8") + await self.validate_appservice_can_control_user_id( + app_service, effective_user_id + ) + else: + effective_user_id = app_service.sender + + effective_device_id: Optional[str] = None + + if ( + self.hs.config.experimental.msc3202_device_masquerading_enabled + and DEVICE_ID_ARG_NAME in request.args + ): + effective_device_id = request.args[DEVICE_ID_ARG_NAME][0].decode("utf8") + # We only just set this so it can't be None! + assert effective_device_id is not None + device_opt = await self.store.get_device( + effective_user_id, effective_device_id + ) + if device_opt is None: + # For now, use 400 M_EXCLUSIVE if the device doesn't exist. + # This is an open thread of discussion on MSC3202 as of 2021-12-09. + raise AuthError( + 400, + f"Application service trying to use a device that doesn't exist ('{effective_device_id}' for {effective_user_id})", + Codes.EXCLUSIVE, + ) + + return create_requester( + effective_user_id, app_service=app_service, device_id=effective_device_id + ) + + async def get_user_by_access_token( + self, + token: str, + allow_expired: bool = False, + ) -> Requester: + """Validate access token and get user_id from it + + Args: + token: The access token to get the user by + allow_expired: If False, raises an InvalidClientTokenError + if the token is expired + + Raises: + InvalidClientTokenError if a user by that token exists, but the token is + expired + InvalidClientCredentialsError if no user by that token exists or the token + is invalid + """ + + # First look in the database to see if the access token is present + # as an opaque token. + user_info = await self.store.get_user_by_access_token(token) + if user_info: + valid_until_ms = user_info.valid_until_ms + if ( + not allow_expired + and valid_until_ms is not None + and valid_until_ms < self.clock.time_msec() + ): + # there was a valid access token, but it has expired. + # soft-logout the user. + raise InvalidClientTokenError( + msg="Access token has expired", soft_logout=True + ) + + # Mark the token as used. This is used to invalidate old refresh + # tokens after some time. + await self.store.mark_access_token_as_used(user_info.token_id) + + requester = create_requester( + user_id=user_info.user_id, + access_token_id=user_info.token_id, + is_guest=user_info.is_guest, + shadow_banned=user_info.shadow_banned, + device_id=user_info.device_id, + authenticated_entity=user_info.token_owner, + ) + + return requester + + # If the token isn't found in the database, then it could still be a + # macaroon for a guest, so we check that here. + try: + user_id = self._macaroon_generator.verify_guest_token(token) + + # 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 = await self.store.get_user_by_id(user_id) + if not stored_user: + raise InvalidClientTokenError("Unknown user_id %s" % user_id) + if not stored_user["is_guest"]: + raise InvalidClientTokenError( + "Guest access token used for regular user" + ) + + return create_requester( + user_id=user_id, + is_guest=True, + # all guests get the same device id + device_id=GUEST_DEVICE_ID, + authenticated_entity=user_id, + ) + except ( + pymacaroons.exceptions.MacaroonException, + TypeError, + ValueError, + ) as e: + logger.warning( + "Invalid access token in auth: %s %s.", + type(e), + e, + ) + raise InvalidClientTokenError("Invalid access token passed.") + + async def is_server_admin(self, requester: Requester) -> bool: + """Check if the given user is a local server admin. + + Args: + requester: The user making the request, according to the access token. + + Returns: + True if the user is an admin + """ + return await self.store.is_server_admin(requester.user) |