Make the api.auth.Auth a Protocol

1 files changed, 0 insertions, 602 deletions

diff --git a/synapse/api/auth.py b/synapse/api/auth.py
deleted file mode 100644
index 66e869bc2d..0000000000
--- a/synapse/api/auth.py
+++ /dev/null
@@ -1,602 +0,0 @@
-# Copyright 2014 - 2016 OpenMarket Ltd
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-import logging
-from typing import TYPE_CHECKING, Optional, Tuple
-
-import pymacaroons
-from netaddr import IPAddress
-
-from twisted.web.server import Request
-
-from synapse import event_auth
-from synapse.api.constants import EventTypes, HistoryVisibility, Membership
-from synapse.api.errors import (
-    AuthError,
-    Codes,
-    InvalidClientTokenError,
-    MissingClientTokenError,
-    UnstableSpecAuthError,
-)
-from synapse.appservice import ApplicationService
-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,
-    trace,
-)
-from synapse.types import Requester, create_requester
-from synapse.util.cancellation import cancellable
-
-if TYPE_CHECKING:
-    from synapse.server import HomeServer
-
-logger = logging.getLogger(__name__)
-
-
-# guests always get this device id.
-GUEST_DEVICE_ID = "guest_device"
-
-
-class Auth:
-    """
-    This class contains functions for authenticating users of our client-server API.
-    """
-
-    def __init__(self, hs: "HomeServer"):
-        self.hs = hs
-        self.clock = hs.get_clock()
-        self.store = hs.get_datastores().main
-        self._account_validity_handler = hs.get_account_validity_handler()
-        self._storage_controllers = hs.get_storage_controllers()
-        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
-
-    async def check_user_in_room(
-        self,
-        room_id: str,
-        requester: Requester,
-        allow_departed_users: bool = False,
-    ) -> Tuple[str, Optional[str]]:
-        """Check if the user is in the room, or was at some point.
-        Args:
-            room_id: The room to check.
-
-            requester: The user making the request, according to the access token.
-
-            current_state: Optional map of the current state of the room.
-                If provided then that map is used to check whether they are a
-                member of the room. Otherwise the current membership is
-                loaded from the database.
-
-            allow_departed_users: if True, accept users that were previously
-                members but have now departed.
-
-        Raises:
-            AuthError if the user is/was not in the room.
-        Returns:
-            The current membership of the user in the room and the
-            membership event ID of the user.
-        """
-
-        user_id = requester.user.to_string()
-        (
-            membership,
-            member_event_id,
-        ) = await self.store.get_local_current_membership_for_user_in_room(
-            user_id=user_id,
-            room_id=room_id,
-        )
-
-        if membership:
-            if membership == Membership.JOIN:
-                return membership, member_event_id
-
-            # XXX this looks totally bogus. Why do we not allow users who have been banned,
-            # or those who were members previously and have been re-invited?
-            if allow_departed_users and membership == Membership.LEAVE:
-                forgot = await self.store.did_forget(user_id, room_id)
-                if not forgot:
-                    return membership, member_event_id
-        raise UnstableSpecAuthError(
-            403,
-            "User %s not in room %s" % (user_id, room_id),
-            errcode=Codes.NOT_JOINED,
-        )
-
-    @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()
-
-    async def validate_appservice_can_control_user_id(
-        self, app_service: ApplicationService, user_id: str
-    ) -> None:
-        """Validates that the app service is allowed to control
-        the given user.
-
-        Args:
-            app_service: The app service that controls the user
-            user_id: The author MXID that the app service is controlling
-
-        Raises:
-            AuthError: If the application service is not allowed to control the user
-                (user namespace regex does not match, wrong homeserver, etc)
-                or if the user has not been registered yet.
-        """
-
-        # It's ok if the app service is trying to use the sender from their registration
-        if app_service.sender == user_id:
-            pass
-        # Check to make sure the app service is allowed to control the user
-        elif not app_service.is_interested_in_user(user_id):
-            raise AuthError(
-                403,
-                "Application service cannot masquerade as this user (%s)." % user_id,
-            )
-        # Check to make sure the user is already registered on the homeserver
-        elif not (await self.store.get_user_by_id(user_id)):
-            raise AuthError(
-                403, "Application service has not registered this user (%s)" % user_id
-            )
-
-    @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)
-
-    async def check_can_change_room_list(
-        self, room_id: str, requester: Requester
-    ) -> bool:
-        """Determine whether the user is allowed to edit the room's entry in the
-        published room list.
-
-        Args:
-            room_id: The room to check.
-            requester: The user making the request, according to the access token.
-        """
-
-        is_admin = await self.is_server_admin(requester)
-        if is_admin:
-            return True
-
-        await self.check_user_in_room(room_id, requester)
-
-        # 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.canonical_alias events
-
-        power_level_event = (
-            await self._storage_controllers.state.get_current_state_event(
-                room_id, EventTypes.PowerLevels, ""
-            )
-        )
-
-        auth_events = {}
-        if power_level_event:
-            auth_events[(EventTypes.PowerLevels, "")] = power_level_event
-
-        send_level = event_auth.get_send_level(
-            EventTypes.CanonicalAlias, "", power_level_event
-        )
-        user_level = event_auth.get_user_power_level(
-            requester.user.to_string(), auth_events
-        )
-
-        return user_level >= send_level
-
-    @staticmethod
-    def has_access_token(request: Request) -> bool:
-        """Checks if the request has an access_token.
-
-        Returns:
-            False if no access_token was given, True otherwise.
-        """
-        # This will always be set by the time Twisted calls us.
-        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,
-            )