Honour AS ratelimit settings for /login requests

Fixes #8846.

synapse/rest/client/v1/login.py

@@ -108,22 +108,27 @@ def on_GET(self, request: SynapseRequest):
         return 200, {"flows": flows}
 
     async def on_POST(self, request: SynapseRequest):
-        self._address_ratelimiter.ratelimit(request.getClientIP())
-
         login_submission = parse_json_object_from_request(request)
 
         try:
             if login_submission["type"] == LoginRestServlet.APPSERVICE_TYPE:
                 appservice = self.auth.get_appservice_by_req(request)
+
+                if appservice.is_rate_limited():
+                    self._address_ratelimiter.ratelimit(request.getClientIP())
+
                 result = await self._do_appservice_login(login_submission, appservice)
             elif self.jwt_enabled and (
                 login_submission["type"] == LoginRestServlet.JWT_TYPE
                 or login_submission["type"] == LoginRestServlet.JWT_TYPE_DEPRECATED
             ):
+                self._address_ratelimiter.ratelimit(request.getClientIP())
                 result = await self._do_jwt_login(login_submission)
             elif login_submission["type"] == LoginRestServlet.TOKEN_TYPE:
+                self._address_ratelimiter.ratelimit(request.getClientIP())
                 result = await self._do_token_login(login_submission)
             else:
+                self._address_ratelimiter.ratelimit(request.getClientIP())
                 result = await self._do_other_login(login_submission)
         except KeyError:
             raise SynapseError(400, "Missing JSON keys.")
@@ -162,7 +167,9 @@ async def _do_appservice_login(
         if not appservice.is_interested_in_user(qualified_user_id):
             raise LoginError(403, "Invalid access_token", errcode=Codes.FORBIDDEN)
 
-        return await self._complete_login(qualified_user_id, login_submission)
+        return await self._complete_login(
+            qualified_user_id, login_submission, ratelimit=appservice.is_rate_limited()
+        )
 
     async def _do_other_login(self, login_submission: JsonDict) -> Dict[str, str]:
         """Handle non-token/saml/jwt logins
@@ -197,6 +204,7 @@ async def _complete_login(
         login_submission: JsonDict,
         callback: Optional[Callable[[Dict[str, str]], Awaitable[None]]] = None,
         create_non_existent_users: bool = False,
+        ratelimit=True,
     ) -> Dict[str, str]:
         """Called when we've successfully authed the user and now need to
         actually login them in (e.g. create devices). This gets called on
@@ -211,6 +219,7 @@ async def _complete_login(
             callback: Callback function to run after login.
             create_non_existent_users: Whether to create the user if they don't
                 exist. Defaults to False.
+            ratelimit: Whether to ratelimit the login request.
 
         Returns:
             result: Dictionary of account information after successful login.
@@ -219,7 +228,8 @@ async def _complete_login(
         # Before we actually log them in we check if they've already logged in
         # too often. This happens here rather than before as we don't
         # necessarily know the user before now.
-        self._account_ratelimiter.ratelimit(user_id.lower())
+        if ratelimit:
+            self._account_ratelimiter.ratelimit(user_id.lower())
 
         if create_non_existent_users:
             canonical_uid = await self.auth_handler.check_user_exists(user_id)