diff --git a/changelog.d/11743.feature b/changelog.d/11743.feature new file mode 100644 index 000000000..9809f48b9 --- /dev/null +++ b/changelog.d/11743.feature @@ -0,0 +1 @@ +Add a config flag to inhibit M_USER_IN_USE during registration. diff --git a/docs/sample_config.yaml b/docs/sample_config.yaml index 1b86d0295..b38e6d6c8 100644 --- a/docs/sample_config.yaml +++ b/docs/sample_config.yaml @@ -1428,6 +1428,16 @@ account_threepid_delegates: # #auto_join_rooms_for_guests: false +# Whether to inhibit errors raised when registering a new account if the user ID +# already exists. If turned on, that requests to /register/available will always +# show a user ID as available, and Synapse won't raise an error when starting +# a registration with a user ID that already exists. However, Synapse will still +# raise an error if the registration completes and the username conflicts. +# +# Defaults to false. +# +#inhibit_user_in_use_error: true + ## Metrics ### diff --git a/synapse/config/registration.py b/synapse/config/registration.py index 7a059c6de..ea9b50fe9 100644 --- a/synapse/config/registration.py +++ b/synapse/config/registration.py @@ -190,6 +190,8 @@ class RegistrationConfig(Config): # The success template used during fallback auth. self.fallback_success_template = self.read_template("auth_success.html") + self.inhibit_user_in_use_error = config.get("inhibit_user_in_use_error", False) + def generate_config_section(self, generate_secrets=False, **kwargs): if generate_secrets: registration_shared_secret = 'registration_shared_secret: "%s"' % ( @@ -446,6 +448,16 @@ class RegistrationConfig(Config): # Defaults to true. # #auto_join_rooms_for_guests: false + + # Whether to inhibit errors raised when registering a new account if the user ID + # already exists. If turned on, that requests to /register/available will always + # show a user ID as available, and Synapse won't raise an error when starting + # a registration with a user ID that already exists. However, Synapse will still + # raise an error if the registration completes and the username conflicts. + # + # Defaults to false. + # + #inhibit_user_in_use_error: true """ % locals() ) diff --git a/synapse/handlers/register.py b/synapse/handlers/register.py index f08a516a7..a719d5eef 100644 --- a/synapse/handlers/register.py +++ b/synapse/handlers/register.py @@ -132,6 +132,7 @@ class RegistrationHandler: localpart: str, guest_access_token: Optional[str] = None, assigned_user_id: Optional[str] = None, + inhibit_user_in_use_error: bool = False, ) -> None: if types.contains_invalid_mxid_characters(localpart): raise SynapseError( @@ -171,21 +172,22 @@ class RegistrationHandler: users = await self.store.get_users_by_id_case_insensitive(user_id) if users: - if not guest_access_token: + if not inhibit_user_in_use_error and not guest_access_token: raise SynapseError( 400, "User ID already taken.", errcode=Codes.USER_IN_USE ) - user_data = await self.auth.get_user_by_access_token(guest_access_token) - if ( - not user_data.is_guest - or UserID.from_string(user_data.user_id).localpart != localpart - ): - raise AuthError( - 403, - "Cannot register taken user ID without valid guest " - "credentials for that user.", - errcode=Codes.FORBIDDEN, - ) + if guest_access_token: + user_data = await self.auth.get_user_by_access_token(guest_access_token) + if ( + not user_data.is_guest + or UserID.from_string(user_data.user_id).localpart != localpart + ): + raise AuthError( + 403, + "Cannot register taken user ID without valid guest " + "credentials for that user.", + errcode=Codes.FORBIDDEN, + ) if guest_access_token is None: try: diff --git a/synapse/rest/client/register.py b/synapse/rest/client/register.py index 8b56c76ae..c59dae7c0 100644 --- a/synapse/rest/client/register.py +++ b/synapse/rest/client/register.py @@ -339,12 +339,19 @@ class UsernameAvailabilityRestServlet(RestServlet): ), ) + self.inhibit_user_in_use_error = ( + hs.config.registration.inhibit_user_in_use_error + ) + async def on_GET(self, request: Request) -> Tuple[int, JsonDict]: if not self.hs.config.registration.enable_registration: raise SynapseError( 403, "Registration has been disabled", errcode=Codes.FORBIDDEN ) + if self.inhibit_user_in_use_error: + return 200, {"available": True} + ip = request.getClientIP() with self.ratelimiter.ratelimit(ip) as wait_deferred: await wait_deferred @@ -422,6 +429,9 @@ class RegisterRestServlet(RestServlet): self._refresh_tokens_enabled = ( hs.config.registration.refreshable_access_token_lifetime is not None ) + self._inhibit_user_in_use_error = ( + hs.config.registration.inhibit_user_in_use_error + ) self._registration_flows = _calculate_registration_flows( hs.config, self.auth_handler @@ -564,6 +574,7 @@ class RegisterRestServlet(RestServlet): desired_username, guest_access_token=guest_access_token, assigned_user_id=registered_user_id, + inhibit_user_in_use_error=self._inhibit_user_in_use_error, ) # Check if the user-interactive authentication flows are complete, if diff --git a/tests/rest/client/test_register.py b/tests/rest/client/test_register.py index 6e7c0f11d..407dd32a7 100644 --- a/tests/rest/client/test_register.py +++ b/tests/rest/client/test_register.py @@ -726,6 +726,47 @@ class RegisterRestServletTestCase(unittest.HomeserverTestCase): {"errcode": "M_UNKNOWN", "error": "Unable to parse email address"}, ) + @override_config( + { + "inhibit_user_in_use_error": True, + } + ) + def test_inhibit_user_in_use_error(self): + """Tests that the 'inhibit_user_in_use_error' configuration flag behaves + correctly. + """ + username = "arthur" + + # Manually register the user, so we know the test isn't passing because of a lack + # of clashing. + reg_handler = self.hs.get_registration_handler() + self.get_success(reg_handler.register_user(username)) + + # Check that /available correctly ignores the username provided despite the + # username being already registered. + channel = self.make_request("GET", "register/available?username=" + username) + self.assertEquals(200, channel.code, channel.result) + + # Test that when starting a UIA registration flow the request doesn't fail because + # of a conflicting username + channel = self.make_request( + "POST", + "register", + {"username": username, "type": "m.login.password", "password": "foo"}, + ) + self.assertEqual(channel.code, 401) + self.assertIn("session", channel.json_body) + + # Test that finishing the registration fails because of a conflicting username. + session = channel.json_body["session"] + channel = self.make_request( + "POST", + "register", + {"auth": {"session": session, "type": LoginType.DUMMY}}, + ) + self.assertEqual(channel.code, 400, channel.json_body) + self.assertEqual(channel.json_body["errcode"], Codes.USER_IN_USE) + class AccountValidityTestCase(unittest.HomeserverTestCase):