Merge pull request #6335 from matrix-org/erikj/rc_login_cleanups

Only do `rc_login` ratelimiting on succesful login.

1 files changed, 31 insertions, 53 deletions

diff --git a/synapse/handlers/auth.py b/synapse/handlers/auth.py
index c9d0db4823..54a71c49d2 100644
--- a/synapse/handlers/auth.py
+++ b/synapse/handlers/auth.py
@@ -102,8 +102,9 @@ class AuthHandler(BaseHandler):
                         login_types.append(t)
         self._supported_login_types = login_types
 
-        self._account_ratelimiter = Ratelimiter()
-        self._failed_attempts_ratelimiter = Ratelimiter()
+        # Ratelimiter for failed auth during UIA. Uses same ratelimit config
+        # as per `rc_login.failed_attempts`.
+        self._failed_uia_attempts_ratelimiter = Ratelimiter()
 
         self._clock = self.hs.get_clock()
 
@@ -133,12 +134,38 @@ class AuthHandler(BaseHandler):
 
             AuthError if the client has completed a login flow, and it gives
                 a different user to `requester`
+
+            LimitExceededError if the ratelimiter's failed request count for this
+                user is too high to proceed
+
         """
 
+        user_id = requester.user.to_string()
+
+        # Check if we should be ratelimited due to too many previous failed attempts
+        self._failed_uia_attempts_ratelimiter.ratelimit(
+            user_id,
+            time_now_s=self._clock.time(),
+            rate_hz=self.hs.config.rc_login_failed_attempts.per_second,
+            burst_count=self.hs.config.rc_login_failed_attempts.burst_count,
+            update=False,
+        )
+
         # build a list of supported flows
         flows = [[login_type] for login_type in self._supported_login_types]
 
-        result, params, _ = yield self.check_auth(flows, request_body, clientip)
+        try:
+            result, params, _ = yield self.check_auth(flows, request_body, clientip)
+        except LoginError:
+            # Update the ratelimite to say we failed (`can_do_action` doesn't raise).
+            self._failed_uia_attempts_ratelimiter.can_do_action(
+                user_id,
+                time_now_s=self._clock.time(),
+                rate_hz=self.hs.config.rc_login_failed_attempts.per_second,
+                burst_count=self.hs.config.rc_login_failed_attempts.burst_count,
+                update=True,
+            )
+            raise
 
         # find the completed login type
         for login_type in self._supported_login_types:
@@ -501,11 +528,8 @@ class AuthHandler(BaseHandler):
             multiple matches
 
         Raises:
-            LimitExceededError if the ratelimiter's login requests count for this
-                user is too high too proceed.
             UserDeactivatedError if a user is found but is deactivated.
         """
-        self.ratelimit_login_per_account(user_id)
         res = yield self._find_user_id_and_pwd_hash(user_id)
         if res is not None:
             return res[0]
@@ -572,8 +596,6 @@ class AuthHandler(BaseHandler):
             StoreError if there was a problem accessing the database
             SynapseError if there was a problem with the request
             LoginError if there was an authentication problem.
-            LimitExceededError if the ratelimiter's login requests count for this
-                user is too high too proceed.
         """
 
         if username.startswith("@"):
@@ -581,8 +603,6 @@ class AuthHandler(BaseHandler):
         else:
             qualified_user_id = UserID(username, self.hs.hostname).to_string()
 
-        self.ratelimit_login_per_account(qualified_user_id)
-
         login_type = login_submission.get("type")
         known_login_type = False
 
@@ -650,15 +670,6 @@ class AuthHandler(BaseHandler):
         if not known_login_type:
             raise SynapseError(400, "Unknown login type %s" % login_type)
 
-        # unknown username or invalid password.
-        self._failed_attempts_ratelimiter.ratelimit(
-            qualified_user_id.lower(),
-            time_now_s=self._clock.time(),
-            rate_hz=self.hs.config.rc_login_failed_attempts.per_second,
-            burst_count=self.hs.config.rc_login_failed_attempts.burst_count,
-            update=True,
-        )
-
         # We raise a 403 here, but note that if we're doing user-interactive
         # login, it turns all LoginErrors into a 401 anyway.
         raise LoginError(403, "Invalid password", errcode=Codes.FORBIDDEN)
@@ -710,10 +721,6 @@ class AuthHandler(BaseHandler):
         Returns:
             Deferred[unicode] the canonical_user_id, or Deferred[None] if
                 unknown user/bad password
-
-        Raises:
-            LimitExceededError if the ratelimiter's login requests count for this
-                user is too high too proceed.
         """
         lookupres = yield self._find_user_id_and_pwd_hash(user_id)
         if not lookupres:
@@ -742,7 +749,7 @@ class AuthHandler(BaseHandler):
             auth_api.validate_macaroon(macaroon, "login", user_id)
         except Exception:
             raise AuthError(403, "Invalid token", errcode=Codes.FORBIDDEN)
-        self.ratelimit_login_per_account(user_id)
+
         yield self.auth.check_auth_blocking(user_id)
         return user_id
 
@@ -912,35 +919,6 @@ class AuthHandler(BaseHandler):
         else:
             return defer.succeed(False)
 
-    def ratelimit_login_per_account(self, user_id):
-        """Checks whether the process must be stopped because of ratelimiting.
-
-        Checks against two ratelimiters: the generic one for login attempts per
-        account and the one specific to failed attempts.
-
-        Args:
-            user_id (unicode): complete @user:id
-
-        Raises:
-            LimitExceededError if one of the ratelimiters' login requests count
-                for this user is too high too proceed.
-        """
-        self._failed_attempts_ratelimiter.ratelimit(
-            user_id.lower(),
-            time_now_s=self._clock.time(),
-            rate_hz=self.hs.config.rc_login_failed_attempts.per_second,
-            burst_count=self.hs.config.rc_login_failed_attempts.burst_count,
-            update=False,
-        )
-
-        self._account_ratelimiter.ratelimit(
-            user_id.lower(),
-            time_now_s=self._clock.time(),
-            rate_hz=self.hs.config.rc_login_account.per_second,
-            burst_count=self.hs.config.rc_login_account.burst_count,
-            update=True,
-        )
-
 
 @attr.s
 class MacaroonGenerator(object):