diff --git a/changelog.d/8345.feature b/changelog.d/8345.feature new file mode 100644 index 000000000..4ee5b6a56 --- /dev/null +++ b/changelog.d/8345.feature @@ -0,0 +1 @@ +Add a configuration option that allows existing users to log in with OpenID Connect. Contributed by @BBBSnowball and @OmmyZhang. diff --git a/docs/sample_config.yaml b/docs/sample_config.yaml index fb04ff283..845f53779 100644 --- a/docs/sample_config.yaml +++ b/docs/sample_config.yaml @@ -1689,6 +1689,11 @@ oidc_config: # #skip_verification: true + # Uncomment to allow a user logging in via OIDC to match a pre-existing account instead + # of failing. This could be used if switching from password logins to OIDC. Defaults to false. + # + #allow_existing_users: true + # An external module can be provided here as a custom solution to mapping # attributes returned from a OIDC provider onto a matrix user. # diff --git a/synapse/config/oidc_config.py b/synapse/config/oidc_config.py index e0939bce8..70fc8a2f6 100644 --- a/synapse/config/oidc_config.py +++ b/synapse/config/oidc_config.py @@ -56,6 +56,7 @@ class OIDCConfig(Config): self.oidc_userinfo_endpoint = oidc_config.get("userinfo_endpoint") self.oidc_jwks_uri = oidc_config.get("jwks_uri") self.oidc_skip_verification = oidc_config.get("skip_verification", False) + self.oidc_allow_existing_users = oidc_config.get("allow_existing_users", False) ump_config = oidc_config.get("user_mapping_provider", {}) ump_config.setdefault("module", DEFAULT_USER_MAPPING_PROVIDER) @@ -158,6 +159,11 @@ class OIDCConfig(Config): # #skip_verification: true + # Uncomment to allow a user logging in via OIDC to match a pre-existing account instead + # of failing. This could be used if switching from password logins to OIDC. Defaults to false. + # + #allow_existing_users: true + # An external module can be provided here as a custom solution to mapping # attributes returned from a OIDC provider onto a matrix user. # diff --git a/synapse/handlers/oidc_handler.py b/synapse/handlers/oidc_handler.py index 4230dbaf9..0e06e4408 100644 --- a/synapse/handlers/oidc_handler.py +++ b/synapse/handlers/oidc_handler.py @@ -114,6 +114,7 @@ class OidcHandler: hs.config.oidc_user_mapping_provider_config ) # type: OidcMappingProvider self._skip_verification = hs.config.oidc_skip_verification # type: bool + self._allow_existing_users = hs.config.oidc_allow_existing_users # type: bool self._http_client = hs.get_proxied_http_client() self._auth_handler = hs.get_auth_handler() @@ -849,7 +850,8 @@ class OidcHandler: If we don't find the user that way, we should register the user, mapping the localpart and the display name from the UserInfo. - If a user already exists with the mxid we've mapped, raise an exception. + If a user already exists with the mxid we've mapped and allow_existing_users + is disabled, raise an exception. Args: userinfo: an object representing the user @@ -905,21 +907,31 @@ class OidcHandler: localpart = map_username_to_mxid_localpart(attributes["localpart"]) - user_id = UserID(localpart, self._hostname) - if await self._datastore.get_users_by_id_case_insensitive(user_id.to_string()): - # This mxid is taken - raise MappingException( - "mxid '{}' is already taken".format(user_id.to_string()) + user_id = UserID(localpart, self._hostname).to_string() + users = await self._datastore.get_users_by_id_case_insensitive(user_id) + if users: + if self._allow_existing_users: + if len(users) == 1: + registered_user_id = next(iter(users)) + elif user_id in users: + registered_user_id = user_id + else: + raise MappingException( + "Attempted to login as '{}' but it matches more than one user inexactly: {}".format( + user_id, list(users.keys()) + ) + ) + else: + # This mxid is taken + raise MappingException("mxid '{}' is already taken".format(user_id)) + else: + # It's the first time this user is logging in and the mapped mxid was + # not taken, register the user + registered_user_id = await self._registration_handler.register_user( + localpart=localpart, + default_display_name=attributes["display_name"], + user_agent_ips=(user_agent, ip_address), ) - - # It's the first time this user is logging in and the mapped mxid was - # not taken, register the user - registered_user_id = await self._registration_handler.register_user( - localpart=localpart, - default_display_name=attributes["display_name"], - user_agent_ips=(user_agent, ip_address), - ) - await self._datastore.record_user_external_id( self._auth_provider_id, remote_user_id, registered_user_id, ) diff --git a/synapse/storage/databases/main/registration.py b/synapse/storage/databases/main/registration.py index 33825e894..48ce7ecd1 100644 --- a/synapse/storage/databases/main/registration.py +++ b/synapse/storage/databases/main/registration.py @@ -393,7 +393,7 @@ class RegistrationWorkerStore(SQLBaseStore): async def get_user_by_external_id( self, auth_provider: str, external_id: str - ) -> str: + ) -> Optional[str]: """Look up a user by their external auth id Args: @@ -401,7 +401,7 @@ class RegistrationWorkerStore(SQLBaseStore): external_id: id on that system Returns: - str|None: the mxid of the user, or None if they are not known + the mxid of the user, or None if they are not known """ return await self.db_pool.simple_select_one_onecol( table="user_external_ids", diff --git a/tests/handlers/test_oidc.py b/tests/handlers/test_oidc.py index 89ec5fcb3..5910772aa 100644 --- a/tests/handlers/test_oidc.py +++ b/tests/handlers/test_oidc.py @@ -617,3 +617,38 @@ class OidcHandlerTestCase(HomeserverTestCase): ) ) self.assertEqual(mxid, "@test_user_2:test") + + # Test if the mxid is already taken + store = self.hs.get_datastore() + user3 = UserID.from_string("@test_user_3:test") + self.get_success( + store.register_user(user_id=user3.to_string(), password_hash=None) + ) + userinfo = {"sub": "test3", "username": "test_user_3"} + e = self.get_failure( + self.handler._map_userinfo_to_user( + userinfo, token, "user-agent", "10.10.10.10" + ), + MappingException, + ) + self.assertEqual(str(e.value), "mxid '@test_user_3:test' is already taken") + + @override_config({"oidc_config": {"allow_existing_users": True}}) + def test_map_userinfo_to_existing_user(self): + """Existing users can log in with OpenID Connect when allow_existing_users is True.""" + store = self.hs.get_datastore() + user4 = UserID.from_string("@test_user_4:test") + self.get_success( + store.register_user(user_id=user4.to_string(), password_hash=None) + ) + userinfo = { + "sub": "test4", + "username": "test_user_4", + } + token = {} + mxid = self.get_success( + self.handler._map_userinfo_to_user( + userinfo, token, "user-agent", "10.10.10.10" + ) + ) + self.assertEqual(mxid, "@test_user_4:test")