# Copyright 2020 The Matrix.org Foundation C.I.C. # # 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 abc import hashlib import io import logging from typing import ( TYPE_CHECKING, Any, Awaitable, Callable, Dict, Iterable, List, Mapping, Optional, Set, ) from urllib.parse import urlencode import attr from typing_extensions import NoReturn, Protocol from twisted.web.iweb import IRequest from twisted.web.server import Request from synapse.api.constants import LoginType from synapse.api.errors import Codes, NotFoundError, RedirectException, SynapseError from synapse.config.sso import SsoAttributeRequirement from synapse.handlers.device import DeviceHandler from synapse.handlers.register import init_counters_for_auth_provider from synapse.handlers.ui_auth import UIAuthSessionDataConstants from synapse.http import get_request_user_agent from synapse.http.server import respond_with_html, respond_with_redirect from synapse.http.site import SynapseRequest from synapse.types import ( JsonDict, StrCollection, UserID, contains_invalid_mxid_characters, create_requester, ) from synapse.util.async_helpers import Linearizer from synapse.util.stringutils import random_string if TYPE_CHECKING: from synapse.server import HomeServer logger = logging.getLogger(__name__) class MappingException(Exception): """Used to catch errors when mapping an SSO response to user attributes. Note that the msg that is raised is shown to end-users. """ class SsoIdentityProvider(Protocol): """Abstract base class to be implemented by SSO Identity Providers An Identity Provider, or IdP, is an external HTTP service which authenticates a user to say whether they should be allowed to log in, or perform a given action. Synapse supports various implementations of IdPs, including OpenID Connect, SAML, and CAS. The main entry point is `handle_redirect_request`, which should return a URI to redirect the user's browser to the IdP's authentication page. Each IdP should be registered with the SsoHandler via `hs.get_sso_handler().register_identity_provider()`, so that requests to `/_matrix/client/r0/login/sso/redirect` can be correctly dispatched. """ @property @abc.abstractmethod def idp_id(self) -> str: """A unique identifier for this SSO provider Eg, "saml", "cas", "github" """ @property @abc.abstractmethod def idp_name(self) -> str: """User-facing name for this provider""" @property def idp_icon(self) -> Optional[str]: """Optional MXC URI for user-facing icon""" return None @property def idp_brand(self) -> Optional[str]: """Optional branding identifier""" return None @abc.abstractmethod async def handle_redirect_request( self, request: SynapseRequest, client_redirect_url: Optional[bytes], ui_auth_session_id: Optional[str] = None, ) -> str: """Handle an incoming request to /login/sso/redirect Args: request: the incoming HTTP request client_redirect_url: the URL that we should redirect the client to after login (or None for UI Auth). ui_auth_session_id: The session ID of the ongoing UI Auth (or None if this is a login). Returns: URL to redirect to """ raise NotImplementedError() @attr.s(auto_attribs=True) class UserAttributes: # NB: This struct is documented in docs/sso_mapping_providers.md so that users can # populate it with data from their own mapping providers. # the localpart of the mxid that the mapper has assigned to the user. # if `None`, the mapper has not picked a userid, and the user should be prompted to # enter one. localpart: Optional[str] confirm_localpart: bool = False display_name: Optional[str] = None picture: Optional[str] = None # mypy thinks these are incompatible for some reason. emails: StrCollection = attr.Factory(list) # type: ignore[assignment] @attr.s(slots=True, auto_attribs=True) class UsernameMappingSession: """Data we track about SSO sessions""" # A unique identifier for this SSO provider, e.g. "oidc" or "saml". auth_provider_id: str # An optional session ID from the IdP. auth_provider_session_id: Optional[str] # user ID on the IdP server remote_user_id: str # attributes returned by the ID mapper display_name: Optional[str] emails: StrCollection # An optional dictionary of extra attributes to be provided to the client in the # login response. extra_login_attributes: Optional[JsonDict] # where to redirect the client back to client_redirect_url: str # expiry time for the session, in milliseconds expiry_time_ms: int # choices made by the user chosen_localpart: Optional[str] = None use_display_name: bool = True emails_to_use: StrCollection = () terms_accepted_version: Optional[str] = None # the HTTP cookie used to track the mapping session id USERNAME_MAPPING_SESSION_COOKIE_NAME = b"username_mapping_session" class SsoHandler: # The number of attempts to ask the mapping provider for when generating an MXID. _MAP_USERNAME_RETRIES = 1000 # the time a UsernameMappingSession remains valid for _MAPPING_SESSION_VALIDITY_PERIOD_MS = 15 * 60 * 1000 def __init__(self, hs: "HomeServer"): self._clock = hs.get_clock() self._store = hs.get_datastores().main self._server_name = hs.hostname self._is_mine_server_name = hs.is_mine_server_name self._registration_handler = hs.get_registration_handler() self._auth_handler = hs.get_auth_handler() self._device_handler = hs.get_device_handler() self._error_template = hs.config.sso.sso_error_template self._bad_user_template = hs.config.sso.sso_auth_bad_user_template self._profile_handler = hs.get_profile_handler() self._media_repo = ( hs.get_media_repository() if hs.config.media.can_load_media_repo else None ) self._http_client = hs.get_proxied_blacklisted_http_client() # The following template is shown after a successful user interactive # authentication session. It tells the user they can close the window. self._sso_auth_success_template = hs.config.sso.sso_auth_success_template self._sso_update_profile_information = ( hs.config.sso.sso_update_profile_information ) # a lock on the mappings self._mapping_lock = Linearizer(name="sso_user_mapping", clock=hs.get_clock()) # a map from session id to session data self._username_mapping_sessions: Dict[str, UsernameMappingSession] = {} # map from idp_id to SsoIdentityProvider self._identity_providers: Dict[str, SsoIdentityProvider] = {} self._consent_at_registration = hs.config.consent.user_consent_at_registration def register_identity_provider(self, p: SsoIdentityProvider) -> None: p_id = p.idp_id assert p_id not in self._identity_providers self._identity_providers[p_id] = p init_counters_for_auth_provider(p_id) def get_identity_providers(self) -> Mapping[str, SsoIdentityProvider]: """Get the configured identity providers""" return self._identity_providers async def get_identity_providers_for_user( self, user_id: str ) -> Mapping[str, SsoIdentityProvider]: """Get the SsoIdentityProviders which a user has used Given a user id, get the identity providers that that user has used to log in with in the past (and thus could use to re-identify themselves for UI Auth). Args: user_id: MXID of user to look up Raises: a map of idp_id to SsoIdentityProvider """ external_ids = await self._store.get_external_ids_by_user(user_id) valid_idps = {} for idp_id, _ in external_ids: idp = self._identity_providers.get(idp_id) if not idp: logger.warning( "User %r has an SSO mapping for IdP %r, but this is no longer " "configured.", user_id, idp_id, ) else: valid_idps[idp_id] = idp return valid_idps def render_error( self, request: Request, error: str, error_description: Optional[str] = None, code: int = 400, ) -> None: """Renders the error template and responds with it. This is used to show errors to the user. The template of this page can be found under `synapse/res/templates/sso_error.html`. Args: request: The incoming request from the browser. We'll respond with an HTML page describing the error. error: A technical identifier for this error. error_description: A human-readable description of the error. code: The integer error code (an HTTP response code) """ html = self._error_template.render( error=error, error_description=error_description ) respond_with_html(request, code, html) async def handle_redirect_request( self, request: SynapseRequest, client_redirect_url: bytes, idp_id: Optional[str], ) -> str: """Handle a request to /login/sso/redirect Args: request: incoming HTTP request client_redirect_url: the URL that we should redirect the client to after login. idp_id: optional identity provider chosen by the client Returns: the URI to redirect to """ if not self._identity_providers: raise SynapseError( 400, "Homeserver not configured for SSO.", errcode=Codes.UNRECOGNIZED ) # if the client chose an IdP, use that idp: Optional[SsoIdentityProvider] = None if idp_id: idp = self._identity_providers.get(idp_id) if not idp: raise NotFoundError("Unknown identity provider") # if we only have one auth provider, redirect to it directly elif len(self._identity_providers) == 1: idp = next(iter(self._identity_providers.values())) if idp: return await idp.handle_redirect_request(request, client_redirect_url) # otherwise, redirect to the IDP picker return "/_synapse/client/pick_idp?" + urlencode( (("redirectUrl", client_redirect_url),) ) async def get_sso_user_by_remote_user_id( self, auth_provider_id: str, remote_user_id: str ) -> Optional[str]: """ Maps the user ID of a remote IdP to a mxid for a previously seen user. If the user has not been seen yet, this will return None. Args: auth_provider_id: A unique identifier for this SSO provider, e.g. "oidc" or "saml". remote_user_id: The user ID according to the remote IdP. This might be an e-mail address, a GUID, or some other form. It must be unique and immutable. Returns: The mxid of a previously seen user. """ logger.debug( "Looking for existing mapping for user %s:%s", auth_provider_id, remote_user_id, ) # Check if we already have a mapping for this user. previously_registered_user_id = await self._store.get_user_by_external_id( auth_provider_id, remote_user_id, ) # A match was found, return the user ID. if previously_registered_user_id is not None: logger.info( "Found existing mapping for IdP '%s' and remote_user_id '%s': %s", auth_provider_id, remote_user_id, previously_registered_user_id, ) return previously_registered_user_id # No match. return None async def complete_sso_login_request( self, auth_provider_id: str, remote_user_id: str, request: SynapseRequest, client_redirect_url: str, sso_to_matrix_id_mapper: Callable[[int], Awaitable[UserAttributes]], grandfather_existing_users: Callable[[], Awaitable[Optional[str]]], extra_login_attributes: Optional[JsonDict] = None, auth_provider_session_id: Optional[str] = None, registration_enabled: bool = True, ) -> None: """ Given an SSO ID, retrieve the user ID for it and possibly register the user. This first checks if the SSO ID has previously been linked to a matrix ID, if it has that matrix ID is returned regardless of the current mapping logic. If a callable is provided for grandfathering users, it is called and can potentially return a matrix ID to use. If it does, the SSO ID is linked to this matrix ID for subsequent calls. The mapping function is called (potentially multiple times) to generate a localpart for the user. If an unused localpart is generated, the user is registered from the given user-agent and IP address and the SSO ID is linked to this matrix ID for subsequent calls. Finally, we generate a redirect to the supplied redirect uri, with a login token Args: auth_provider_id: A unique identifier for this SSO provider, e.g. "oidc" or "saml". remote_user_id: The unique identifier from the SSO provider. request: The request to respond to client_redirect_url: The redirect URL passed in by the client. sso_to_matrix_id_mapper: A callable to generate the user attributes. The only parameter is an integer which represents the amount of times the returned mxid localpart mapping has failed. It is expected that the mapper can raise two exceptions, which will get passed through to the caller: MappingException if there was a problem mapping the response to the user. RedirectException to redirect to an additional page (e.g. to prompt the user for more information). grandfather_existing_users: A callable which can return an previously existing matrix ID. The SSO ID is then linked to the returned matrix ID. extra_login_attributes: An optional dictionary of extra attributes to be provided to the client in the login response. auth_provider_session_id: An optional session ID from the IdP. registration_enabled: An optional boolean to enable/disable automatic registrations of new users. If false and the user does not exist then the flow is aborted. Defaults to true. Raises: MappingException if there was a problem mapping the response to a user. RedirectException: if the mapping provider needs to redirect the user to an additional page. (e.g. to prompt for more information) """ new_user = False # grab a lock while we try to find a mapping for this user. This seems... # optimistic, especially for implementations that end up redirecting to # interstitial pages. async with self._mapping_lock.queue(auth_provider_id): # first of all, check if we already have a mapping for this user user_id = await self.get_sso_user_by_remote_user_id( auth_provider_id, remote_user_id, ) # Check for grandfathering of users. if not user_id: user_id = await grandfather_existing_users() if user_id: # Future logins should also match this user ID. await self._store.record_user_external_id( auth_provider_id, remote_user_id, user_id ) if not user_id and not registration_enabled: logger.info( "User does not exist and registration are disabled for IdP '%s' and remote_user_id '%s'", auth_provider_id, remote_user_id, ) raise MappingException( "User does not exist and registrations are disabled" ) elif not user_id: # Otherwise, generate a new user. attributes = await self._call_attribute_mapper(sso_to_matrix_id_mapper) next_step_url = self._get_url_for_next_new_user_step( attributes=attributes ) if next_step_url: await self._redirect_to_next_new_user_step( auth_provider_id, remote_user_id, attributes, client_redirect_url, next_step_url, extra_login_attributes, auth_provider_session_id, ) user_id = await self._register_mapped_user( attributes, auth_provider_id, remote_user_id, get_request_user_agent(request), request.getClientAddress().host, ) new_user = True elif self._sso_update_profile_information: attributes = await self._call_attribute_mapper(sso_to_matrix_id_mapper) if attributes.display_name: user_id_obj = UserID.from_string(user_id) profile_display_name = await self._profile_handler.get_displayname( user_id_obj ) if profile_display_name != attributes.display_name: requester = create_requester( user_id, authenticated_entity=user_id, ) await self._profile_handler.set_displayname( user_id_obj, requester, attributes.display_name, True ) if attributes.picture: await self.set_avatar(user_id, attributes.picture) await self._auth_handler.complete_sso_login( user_id, auth_provider_id, request, client_redirect_url, extra_login_attributes, new_user=new_user, auth_provider_session_id=auth_provider_session_id, ) async def _call_attribute_mapper( self, sso_to_matrix_id_mapper: Callable[[int], Awaitable[UserAttributes]], ) -> UserAttributes: """Call the attribute mapper function in a loop, until we get a unique userid""" for i in range(self._MAP_USERNAME_RETRIES): try: attributes = await sso_to_matrix_id_mapper(i) except (RedirectException, MappingException): # Mapping providers are allowed to issue a redirect (e.g. to ask # the user for more information) and can issue a mapping exception # if a name cannot be generated. raise except Exception as e: # Any other exception is unexpected. raise MappingException( "Could not extract user attributes from SSO response." ) from e logger.debug( "Retrieved user attributes from user mapping provider: %r (attempt %d)", attributes, i, ) if not attributes.localpart: # the mapper has not picked a localpart return attributes # Check if this mxid already exists user_id = UserID(attributes.localpart, self._server_name).to_string() if not await self._store.get_users_by_id_case_insensitive(user_id): # This mxid is free break else: # Unable to generate a username in 1000 iterations # Break and return error to the user raise MappingException( "Unable to generate a Matrix ID from the SSO response" ) return attributes def _get_url_for_next_new_user_step( self, attributes: Optional[UserAttributes] = None, session: Optional[UsernameMappingSession] = None, ) -> bytes: """Returns the URL to redirect to for the next step of new user registration Given attributes from the user mapping provider or a UsernameMappingSession, returns the URL to redirect to for the next step of the registration flow. Args: attributes: the user attributes returned by the user mapping provider, from before a UsernameMappingSession has begun. session: an active UsernameMappingSession, possibly with some of its attributes chosen by the user. Returns: The URL to redirect to, or an empty value if no redirect is necessary """ # Must provide either attributes or session, not both assert (attributes is not None) != (session is not None) if ( attributes and (attributes.localpart is None or attributes.confirm_localpart is True) ) or (session and session.chosen_localpart is None): return b"/_synapse/client/pick_username/account_details" elif self._consent_at_registration and not ( session and session.terms_accepted_version ): return b"/_synapse/client/new_user_consent" else: return b"/_synapse/client/sso_register" if session else b"" async def _redirect_to_next_new_user_step( self, auth_provider_id: str, remote_user_id: str, attributes: UserAttributes, client_redirect_url: str, next_step_url: bytes, extra_login_attributes: Optional[JsonDict], auth_provider_session_id: Optional[str], ) -> NoReturn: """Creates a UsernameMappingSession and redirects the browser Called if the user mapping provider doesn't return complete information for a new user. Raises a RedirectException which redirects the browser to a specified URL. Args: auth_provider_id: A unique identifier for this SSO provider, e.g. "oidc" or "saml". remote_user_id: The unique identifier from the SSO provider. attributes: the user attributes returned by the user mapping provider. client_redirect_url: The redirect URL passed in by the client, which we will eventually redirect back to. next_step_url: The URL to redirect to for the next step of the new user flow. extra_login_attributes: An optional dictionary of extra attributes to be provided to the client in the login response. auth_provider_session_id: An optional session ID from the IdP. Raises: RedirectException """ # TODO: If needed, allow using/looking up an existing session here. session_id = random_string(16) now = self._clock.time_msec() session = UsernameMappingSession( auth_provider_id=auth_provider_id, auth_provider_session_id=auth_provider_session_id, remote_user_id=remote_user_id, display_name=attributes.display_name, emails=attributes.emails, client_redirect_url=client_redirect_url, expiry_time_ms=now + self._MAPPING_SESSION_VALIDITY_PERIOD_MS, extra_login_attributes=extra_login_attributes, # Treat the localpart returned by the user mapping provider as though # it was chosen by the user. If it's None, it must be chosen eventually. chosen_localpart=attributes.localpart, # TODO: Consider letting the user mapping provider specify defaults for # other user-chosen attributes. ) self._username_mapping_sessions[session_id] = session logger.info("Recorded registration session id %s", session_id) # Set the cookie and redirect to the next step e = RedirectException(next_step_url) e.cookies.append( b"%s=%s; path=/" % (USERNAME_MAPPING_SESSION_COOKIE_NAME, session_id.encode("ascii")) ) raise e async def _register_mapped_user( self, attributes: UserAttributes, auth_provider_id: str, remote_user_id: str, user_agent: str, ip_address: str, ) -> str: """Register a new SSO user. This is called once we have successfully mapped the remote user id onto a local user id, one way or another. Args: attributes: user attributes returned by the user mapping provider, including a non-empty localpart. auth_provider_id: A unique identifier for this SSO provider, e.g. "oidc" or "saml". remote_user_id: The unique identifier from the SSO provider. user_agent: The user-agent in the HTTP request (used for potential shadow-banning.) ip_address: The IP address of the requester (used for potential shadow-banning.) Raises: a MappingException if the localpart is invalid. a SynapseError with code 400 and errcode Codes.USER_IN_USE if the localpart is already taken. """ # Since the localpart is provided via a potentially untrusted module, # ensure the MXID is valid before registering. if not attributes.localpart or contains_invalid_mxid_characters( attributes.localpart ): raise MappingException("localpart is invalid: %s" % (attributes.localpart,)) logger.debug("Mapped SSO user to local part %s", attributes.localpart) registered_user_id = await self._registration_handler.register_user( localpart=attributes.localpart, default_display_name=attributes.display_name, bind_emails=attributes.emails, user_agent_ips=[(user_agent, ip_address)], auth_provider_id=auth_provider_id, ) await self._store.record_user_external_id( auth_provider_id, remote_user_id, registered_user_id ) # Set avatar, if available if attributes.picture: await self.set_avatar(registered_user_id, attributes.picture) return registered_user_id async def set_avatar(self, user_id: str, picture_https_url: str) -> bool: """Set avatar of the user. This downloads the image file from the URL provided, stores that in the media repository and then sets the avatar on the user's profile. It can detect if the same image is being saved again and bails early by storing the hash of the file in the `upload_name` of the avatar image. Currently, it only supports server configurations which run the media repository within the same process. It silently fails and logs a warning by raising an exception and catching it internally if: * it is unable to fetch the image itself (non 200 status code) or * the image supplied is bigger than max allowed size or * the image type is not one of the allowed image types. Args: user_id: matrix user ID in the form @localpart:domain as a string. picture_https_url: HTTPS url for the picture image file. Returns: `True` if the user's avatar has been successfully set to the image at `picture_https_url`. """ if self._media_repo is None: logger.info( "failed to set user avatar because out-of-process media repositories " "are not supported yet " ) return False try: uid = UserID.from_string(user_id) def is_allowed_mime_type(content_type: str) -> bool: if ( self._profile_handler.allowed_avatar_mimetypes and content_type not in self._profile_handler.allowed_avatar_mimetypes ): return False return True # download picture, enforcing size limit & mime type check picture = io.BytesIO() content_length, headers, uri, code = await self._http_client.get_file( url=picture_https_url, output_stream=picture, max_size=self._profile_handler.max_avatar_size, is_allowed_content_type=is_allowed_mime_type, ) if code != 200: raise Exception( "GET request to download sso avatar image returned {}".format(code) ) # upload name includes hash of the image file's content so that we can # easily check if it requires an update or not, the next time user logs in upload_name = "sso_avatar_" + hashlib.sha256(picture.read()).hexdigest() # bail if user already has the same avatar profile = await self._profile_handler.get_profile(user_id) if profile["avatar_url"] is not None: server_name = profile["avatar_url"].split("/")[-2] media_id = profile["avatar_url"].split("/")[-1] if self._is_mine_server_name(server_name): media = await self._media_repo.store.get_local_media(media_id) if media is not None and upload_name == media["upload_name"]: logger.info("skipping saving the user avatar") return True # store it in media repository avatar_mxc_url = await self._media_repo.create_content( media_type=headers[b"Content-Type"][0].decode("utf-8"), upload_name=upload_name, content=picture, content_length=content_length, auth_user=uid, ) # save it as user avatar await self._profile_handler.set_avatar_url( uid, create_requester(uid), str(avatar_mxc_url), ) logger.info("successfully saved the user avatar") return True except Exception: logger.warning("failed to save the user avatar") return False async def complete_sso_ui_auth_request( self, auth_provider_id: str, remote_user_id: str, ui_auth_session_id: str, request: Request, ) -> None: """ Given an SSO ID, retrieve the user ID for it and complete UIA. Note that this requires that the user is mapped in the "user_external_ids" table. This will be the case if they have ever logged in via SAML or OIDC in recentish synapse versions, but may not be for older users. Args: auth_provider_id: A unique identifier for this SSO provider, e.g. "oidc" or "saml". remote_user_id: The unique identifier from the SSO provider. ui_auth_session_id: The ID of the user-interactive auth session. request: The request to complete. """ user_id = await self.get_sso_user_by_remote_user_id( auth_provider_id, remote_user_id, ) user_id_to_verify: str = await self._auth_handler.get_session_data( ui_auth_session_id, UIAuthSessionDataConstants.REQUEST_USER_ID ) if not user_id: logger.warning( "Remote user %s/%s has not previously logged in here: UIA will fail", auth_provider_id, remote_user_id, ) elif user_id != user_id_to_verify: logger.warning( "Remote user %s/%s mapped onto incorrect user %s: UIA will fail", auth_provider_id, remote_user_id, user_id, ) else: # success! # Mark the stage of the authentication as successful. await self._store.mark_ui_auth_stage_complete( ui_auth_session_id, LoginType.SSO, user_id ) # Render the HTML confirmation page and return. html = self._sso_auth_success_template respond_with_html(request, 200, html) return # the user_id didn't match: mark the stage of the authentication as unsuccessful await self._store.mark_ui_auth_stage_complete( ui_auth_session_id, LoginType.SSO, "" ) # render an error page. html = self._bad_user_template.render( server_name=self._server_name, user_id_to_verify=user_id_to_verify, ) respond_with_html(request, 200, html) def get_mapping_session(self, session_id: str) -> UsernameMappingSession: """Look up the given username mapping session If it is not found, raises a SynapseError with an http code of 400 Args: session_id: session to look up Returns: active mapping session Raises: SynapseError if the session is not found/has expired """ self._expire_old_sessions() session = self._username_mapping_sessions.get(session_id) if session: return session logger.info("Couldn't find session id %s", session_id) raise SynapseError(400, "unknown session") async def check_username_availability( self, localpart: str, session_id: str, ) -> bool: """Handle an "is username available" callback check Args: localpart: desired localpart session_id: the session id for the username picker Returns: True if the username is available Raises: SynapseError if the localpart is invalid or the session is unknown """ # make sure that there is a valid mapping session, to stop people dictionary- # scanning for accounts self.get_mapping_session(session_id) logger.info( "[session %s] Checking for availability of username %s", session_id, localpart, ) if contains_invalid_mxid_characters(localpart): raise SynapseError(400, "localpart is invalid: %s" % (localpart,)) user_id = UserID(localpart, self._server_name).to_string() user_infos = await self._store.get_users_by_id_case_insensitive(user_id) logger.info("[session %s] users: %s", session_id, user_infos) return not user_infos async def handle_submit_username_request( self, request: SynapseRequest, session_id: str, localpart: str, use_display_name: bool, emails_to_use: Iterable[str], ) -> None: """Handle a request to the username-picker 'submit' endpoint Will serve an HTTP response to the request. Args: request: HTTP request localpart: localpart requested by the user session_id: ID of the username mapping session, extracted from a cookie use_display_name: whether the user wants to use the suggested display name emails_to_use: emails that the user would like to use """ try: session = self.get_mapping_session(session_id) except SynapseError as e: self.render_error(request, "bad_session", e.msg, code=e.code) return # update the session with the user's choices session.chosen_localpart = localpart session.use_display_name = use_display_name emails_from_idp = set(session.emails) filtered_emails: Set[str] = set() # we iterate through the list rather than just building a set conjunction, so # that we can log attempts to use unknown addresses for email in emails_to_use: if email in emails_from_idp: filtered_emails.add(email) else: logger.warning( "[session %s] ignoring user request to use unknown email address %r", session_id, email, ) session.emails_to_use = filtered_emails respond_with_redirect( request, self._get_url_for_next_new_user_step(session=session) ) async def handle_terms_accepted( self, request: SynapseRequest, session_id: str, terms_version: str ) -> None: """Handle a request to the new-user 'consent' endpoint Will serve an HTTP response to the request. Args: request: HTTP request session_id: ID of the username mapping session, extracted from a cookie terms_version: the version of the terms which the user viewed and consented to """ logger.info( "[session %s] User consented to terms version %s", session_id, terms_version, ) try: session = self.get_mapping_session(session_id) except SynapseError as e: self.render_error(request, "bad_session", e.msg, code=e.code) return session.terms_accepted_version = terms_version respond_with_redirect( request, self._get_url_for_next_new_user_step(session=session) ) async def register_sso_user(self, request: Request, session_id: str) -> None: """Called once we have all the info we need to register a new user. Does so and serves an HTTP response Args: request: HTTP request session_id: ID of the username mapping session, extracted from a cookie """ try: session = self.get_mapping_session(session_id) except SynapseError as e: self.render_error(request, "bad_session", e.msg, code=e.code) return logger.info( "[session %s] Registering localpart %s", session_id, session.chosen_localpart, ) attributes = UserAttributes( localpart=session.chosen_localpart, emails=session.emails_to_use, ) if session.use_display_name: attributes.display_name = session.display_name # the following will raise a 400 error if the username has been taken in the # meantime. user_id = await self._register_mapped_user( attributes, session.auth_provider_id, session.remote_user_id, get_request_user_agent(request), request.getClientAddress().host, ) logger.info( "[session %s] Registered userid %s with attributes %s", session_id, user_id, attributes, ) # delete the mapping session and the cookie del self._username_mapping_sessions[session_id] # delete the cookie request.addCookie( USERNAME_MAPPING_SESSION_COOKIE_NAME, b"", expires=b"Thu, 01 Jan 1970 00:00:00 GMT", path=b"/", ) auth_result = {} if session.terms_accepted_version: # TODO: make this less awful. auth_result[LoginType.TERMS] = True await self._registration_handler.post_registration_actions( user_id, auth_result, access_token=None ) await self._auth_handler.complete_sso_login( user_id, session.auth_provider_id, request, session.client_redirect_url, session.extra_login_attributes, new_user=True, auth_provider_session_id=session.auth_provider_session_id, ) def _expire_old_sessions(self) -> None: to_expire = [] now = int(self._clock.time_msec()) for session_id, session in self._username_mapping_sessions.items(): if session.expiry_time_ms <= now: to_expire.append(session_id) for session_id in to_expire: logger.info("Expiring mapping session %s", session_id) del self._username_mapping_sessions[session_id] def check_required_attributes( self, request: SynapseRequest, attributes: Mapping[str, List[Any]], attribute_requirements: Iterable[SsoAttributeRequirement], ) -> bool: """ Confirm that the required attributes were present in the SSO response. If all requirements are met, this will return True. If any requirement is not met, then the request will be finalized by showing an error page to the user and False will be returned. Args: request: The request to (potentially) respond to. attributes: The attributes from the SSO IdP. attribute_requirements: The requirements that attributes must meet. Returns: True if all requirements are met, False if any attribute fails to meet the requirement. """ # Ensure that the attributes of the logged in user meet the required # attributes. for requirement in attribute_requirements: if not _check_attribute_requirement(attributes, requirement): self.render_error( request, "unauthorised", "You are not authorised to log in here." ) return False return True async def revoke_sessions_for_provider_session_id( self, auth_provider_id: str, auth_provider_session_id: str, expected_user_id: Optional[str] = None, ) -> None: """Revoke any devices and in-flight logins tied to a provider session. Can only be called from the main process. Args: auth_provider_id: A unique identifier for this SSO provider, e.g. "oidc" or "saml". auth_provider_session_id: The session ID from the provider to logout expected_user_id: The user we're expecting to logout. If set, it will ignore sessions belonging to other users and log an error. """ # It is expected that this is the main process. assert isinstance( self._device_handler, DeviceHandler ), "revoking SSO sessions can only be called on the main process" # Invalidate any running user-mapping sessions to_delete = [] for session_id, session in self._username_mapping_sessions.items(): if ( session.auth_provider_id == auth_provider_id and session.auth_provider_session_id == auth_provider_session_id ): to_delete.append(session_id) for session_id in to_delete: logger.info("Revoking mapping session %s", session_id) del self._username_mapping_sessions[session_id] # Invalidate any in-flight login tokens await self._store.invalidate_login_tokens_by_session_id( auth_provider_id=auth_provider_id, auth_provider_session_id=auth_provider_session_id, ) # Fetch any device(s) in the store associated with the session ID. devices = await self._store.get_devices_by_auth_provider_session_id( auth_provider_id=auth_provider_id, auth_provider_session_id=auth_provider_session_id, ) # We have no guarantee that all the devices of that session are for the same # `user_id`. Hence, we have to iterate over the list of devices and log them out # one by one. for device in devices: user_id = device["user_id"] device_id = device["device_id"] # If the user_id associated with that device/session is not the one we got # out of the `sub` claim, skip that device and show log an error. if expected_user_id is not None and user_id != expected_user_id: logger.error( "Received a logout notification from SSO provider " f"{auth_provider_id!r} for the user {expected_user_id!r}, but with " f"a session ID ({auth_provider_session_id!r}) which belongs to " f"{user_id!r}. This may happen when the SSO provider user mapper " "uses something else than the standard attribute as mapping ID. " "For OIDC providers, set `backchannel_logout_ignore_sub` to `true` " "in the provider config if that is the case." ) continue logger.info( "Logging out %r (device %r) via SSO (%r) logout notification (session %r).", user_id, device_id, auth_provider_id, auth_provider_session_id, ) await self._device_handler.delete_devices(user_id, [device_id]) def get_username_mapping_session_cookie_from_request(request: IRequest) -> str: """Extract the session ID from the cookie Raises a SynapseError if the cookie isn't found """ session_id = request.getCookie(USERNAME_MAPPING_SESSION_COOKIE_NAME) if not session_id: raise SynapseError(code=400, msg="missing session_id") return session_id.decode("ascii", errors="replace") def _check_attribute_requirement( attributes: Mapping[str, List[Any]], req: SsoAttributeRequirement ) -> bool: """Check if SSO attributes meet the proper requirements. Args: attributes: A mapping of attributes to an iterable of one or more values. requirement: The configured requirement to check. Returns: True if the required attribute was found and had a proper value. """ if req.attribute not in attributes: logger.info("SSO attribute missing: %s", req.attribute) return False # If the requirement is None, the attribute existing is enough. if req.value is None: return True values = attributes[req.attribute] if req.value in values: return True logger.info( "SSO attribute %s did not match required value '%s' (was '%s')", req.attribute, req.value, values, ) return False