From 8388384a640d3381b5858d3fb1d2ea0a8c9c059c Mon Sep 17 00:00:00 2001 From: Patrick Cloke Date: Wed, 2 Dec 2020 07:45:42 -0500 Subject: [PATCH] Fix a regression when grandfathering SAML users. (#8855) This was broken in #8801 when abstracting code shared with OIDC. After this change both SAML and OIDC have a concept of grandfathering users, but with different implementations. --- changelog.d/8855.feature | 1 + synapse/handlers/oidc_handler.py | 30 ++++++++++++++-- synapse/handlers/saml_handler.py | 9 ++--- synapse/handlers/sso.py | 60 ++++++++++---------------------- tests/handlers/test_oidc.py | 8 +++++ tests/handlers/test_saml.py | 34 +++++++++++++++++- 6 files changed, 94 insertions(+), 48 deletions(-) create mode 100644 changelog.d/8855.feature diff --git a/changelog.d/8855.feature b/changelog.d/8855.feature new file mode 100644 index 0000000000..77f7fe4e5d --- /dev/null +++ b/changelog.d/8855.feature @@ -0,0 +1 @@ +Add support for re-trying generation of a localpart for OpenID Connect mapping providers. diff --git a/synapse/handlers/oidc_handler.py b/synapse/handlers/oidc_handler.py index 78c4e94a9d..55c4377890 100644 --- a/synapse/handlers/oidc_handler.py +++ b/synapse/handlers/oidc_handler.py @@ -39,7 +39,7 @@ from synapse.handlers._base import BaseHandler from synapse.handlers.sso import MappingException, UserAttributes from synapse.http.site import SynapseRequest from synapse.logging.context import make_deferred_yieldable -from synapse.types import JsonDict, map_username_to_mxid_localpart +from synapse.types import JsonDict, UserID, map_username_to_mxid_localpart from synapse.util import json_decoder if TYPE_CHECKING: @@ -898,13 +898,39 @@ class OidcHandler(BaseHandler): return UserAttributes(**attributes) + async def grandfather_existing_users() -> Optional[str]: + if self._allow_existing_users: + # If allowing existing users we want to generate a single localpart + # and attempt to match it. + attributes = await oidc_response_to_user_attributes(failures=0) + + user_id = UserID(attributes.localpart, self.server_name).to_string() + users = await self.store.get_users_by_id_case_insensitive(user_id) + if users: + # If an existing matrix ID is returned, then use it. + if len(users) == 1: + previously_registered_user_id = next(iter(users)) + elif user_id in users: + previously_registered_user_id = user_id + else: + # Do not attempt to continue generating Matrix IDs. + raise MappingException( + "Attempted to login as '{}' but it matches more than one user inexactly: {}".format( + user_id, users + ) + ) + + return previously_registered_user_id + + return None + return await self._sso_handler.get_mxid_from_sso( self._auth_provider_id, remote_user_id, user_agent, ip_address, oidc_response_to_user_attributes, - self._allow_existing_users, + grandfather_existing_users, ) diff --git a/synapse/handlers/saml_handler.py b/synapse/handlers/saml_handler.py index 7ffad7d8af..76d4169fe2 100644 --- a/synapse/handlers/saml_handler.py +++ b/synapse/handlers/saml_handler.py @@ -268,7 +268,7 @@ class SamlHandler(BaseHandler): emails=result.get("emails", []), ) - with (await self._mapping_lock.queue(self._auth_provider_id)): + async def grandfather_existing_users() -> Optional[str]: # backwards-compatibility hack: see if there is an existing user with a # suitable mapping from the uid if ( @@ -290,17 +290,18 @@ class SamlHandler(BaseHandler): if users: registered_user_id = list(users.keys())[0] logger.info("Grandfathering mapping to %s", registered_user_id) - await self.store.record_user_external_id( - self._auth_provider_id, remote_user_id, registered_user_id - ) return registered_user_id + return None + + with (await self._mapping_lock.queue(self._auth_provider_id)): return await self._sso_handler.get_mxid_from_sso( self._auth_provider_id, remote_user_id, user_agent, ip_address, saml_response_to_remapped_user_attributes, + grandfather_existing_users, ) def expire_sessions(self): diff --git a/synapse/handlers/sso.py b/synapse/handlers/sso.py index d963082210..f42b90e1bc 100644 --- a/synapse/handlers/sso.py +++ b/synapse/handlers/sso.py @@ -116,7 +116,7 @@ class SsoHandler(BaseHandler): user_agent: str, ip_address: str, sso_to_matrix_id_mapper: Callable[[int], Awaitable[UserAttributes]], - allow_existing_users: bool = False, + grandfather_existing_users: Optional[Callable[[], Awaitable[Optional[str]]]], ) -> str: """ Given an SSO ID, retrieve the user ID for it and possibly register the user. @@ -125,6 +125,10 @@ class SsoHandler(BaseHandler): 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. @@ -132,17 +136,6 @@ class SsoHandler(BaseHandler): given user-agent and IP address and the SSO ID is linked to this matrix ID for subsequent calls. - If allow_existing_users is true the mapping function is only called once - and results in: - - 1. The use of a previously registered matrix ID. In this case, the - SSO ID is linked to the matrix ID. (Note it is possible that - other SSO IDs are linked to the same matrix ID.) - 2. An unused localpart, in which case the user is registered (as - discussed above). - 3. An error if the generated localpart matches multiple pre-existing - matrix IDs. Generally this should not happen. - Args: auth_provider_id: A unique identifier for this SSO provider, e.g. "oidc" or "saml". @@ -152,8 +145,9 @@ class SsoHandler(BaseHandler): 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. - allow_existing_users: True if the localpart returned from the - mapping provider can be linked to an existing matrix ID. + grandfather_existing_users: A callable which can return an previously + existing matrix ID. The SSO ID is then linked to the returned + matrix ID. Returns: The user ID associated with the SSO response. @@ -171,6 +165,16 @@ class SsoHandler(BaseHandler): if previously_registered_user_id: return previously_registered_user_id + # Check for grandfathering of users. + if grandfather_existing_users: + previously_registered_user_id = await grandfather_existing_users() + if previously_registered_user_id: + # Future logins should also match this user ID. + await self.store.record_user_external_id( + auth_provider_id, remote_user_id, previously_registered_user_id + ) + return previously_registered_user_id + # Otherwise, generate a new user. for i in range(self._MAP_USERNAME_RETRIES): try: @@ -194,33 +198,7 @@ class SsoHandler(BaseHandler): # Check if this mxid already exists user_id = UserID(attributes.localpart, self.server_name).to_string() - users = await self.store.get_users_by_id_case_insensitive(user_id) - # Note, if allow_existing_users is true then the loop is guaranteed - # to end on the first iteration: either by matching an existing user, - # raising an error, or registering a new user. See the docstring for - # more in-depth an explanation. - if users and allow_existing_users: - # If an existing matrix ID is returned, then use it. - if len(users) == 1: - previously_registered_user_id = next(iter(users)) - elif user_id in users: - previously_registered_user_id = user_id - else: - # Do not attempt to continue generating Matrix IDs. - raise MappingException( - "Attempted to login as '{}' but it matches more than one user inexactly: {}".format( - user_id, users - ) - ) - - # Future logins should also match this user ID. - await self.store.record_user_external_id( - auth_provider_id, remote_user_id, previously_registered_user_id - ) - - return previously_registered_user_id - - elif not users: + if not await self.store.get_users_by_id_case_insensitive(user_id): # This mxid is free break else: diff --git a/tests/handlers/test_oidc.py b/tests/handlers/test_oidc.py index c9807a7b73..d485af52fd 100644 --- a/tests/handlers/test_oidc.py +++ b/tests/handlers/test_oidc.py @@ -731,6 +731,14 @@ class OidcHandlerTestCase(HomeserverTestCase): ) self.assertEqual(mxid, "@test_user:test") + # Subsequent calls should map to the same mxid. + mxid = self.get_success( + self.handler._map_userinfo_to_user( + userinfo, token, "user-agent", "10.10.10.10" + ) + ) + self.assertEqual(mxid, "@test_user:test") + # Note that a second SSO user can be mapped to the same Matrix ID. (This # requires a unique sub, but something that maps to the same matrix ID, # in this case we'll just use the same username. A more realistic example diff --git a/tests/handlers/test_saml.py b/tests/handlers/test_saml.py index 79fd47036f..e1e13a5faf 100644 --- a/tests/handlers/test_saml.py +++ b/tests/handlers/test_saml.py @@ -16,7 +16,7 @@ import attr from synapse.handlers.sso import MappingException -from tests.unittest import HomeserverTestCase +from tests.unittest import HomeserverTestCase, override_config # These are a few constants that are used as config parameters in the tests. BASE_URL = "https://synapse/" @@ -59,6 +59,10 @@ class SamlHandlerTestCase(HomeserverTestCase): "grandfathered_mxid_source_attribute": None, "user_mapping_provider": {"module": __name__ + ".TestMappingProvider"}, } + + # Update this config with what's in the default config so that + # override_config works as expected. + saml_config.update(config.get("saml2_config", {})) config["saml2_config"] = saml_config return config @@ -86,6 +90,34 @@ class SamlHandlerTestCase(HomeserverTestCase): ) self.assertEqual(mxid, "@test_user:test") + @override_config({"saml2_config": {"grandfathered_mxid_source_attribute": "mxid"}}) + def test_map_saml_response_to_existing_user(self): + """Existing users can log in with SAML account.""" + store = self.hs.get_datastore() + self.get_success( + store.register_user(user_id="@test_user:test", password_hash=None) + ) + + # Map a user via SSO. + saml_response = FakeAuthnResponse( + {"uid": "tester", "mxid": ["test_user"], "username": "test_user"} + ) + redirect_url = "" + mxid = self.get_success( + self.handler._map_saml_response_to_user( + saml_response, redirect_url, "user-agent", "10.10.10.10" + ) + ) + self.assertEqual(mxid, "@test_user:test") + + # Subsequent calls should map to the same mxid. + mxid = self.get_success( + self.handler._map_saml_response_to_user( + saml_response, redirect_url, "user-agent", "10.10.10.10" + ) + ) + self.assertEqual(mxid, "@test_user:test") + def test_map_saml_response_to_invalid_localpart(self): """If the mapping provider generates an invalid localpart it should be rejected.""" saml_response = FakeAuthnResponse({"uid": "test", "username": "föö"})