2 files changed, 30 insertions, 7 deletions
diff --git a/synapse/api/auth.py b/synapse/api/auth.py
index 91b23ff1d7..ab1e3a4e35 100644
--- a/synapse/api/auth.py
+++ b/synapse/api/auth.py
@@ -775,13 +775,31 @@ class Auth(object):
             )
 
     @defer.inlineCallbacks
-    def check_auth_blocking(self):
+    def check_auth_blocking(self, user_id=None):
         """Checks if the user should be rejected for some external reason,
         such as monthly active user limiting or global disable flag
+
+        Args:
+            user_id(str|None): If present, checks for presence against existing
+            MAU cohort
         """
+        if self.hs.config.hs_disabled:
+            raise AuthError(
+                403, self.hs.config.hs_disabled_message,
+                errcode=Codes.RESOURCE_LIMIT_EXCEED,
+                admin_uri=self.hs.config.admin_uri,
+            )
         if self.hs.config.limit_usage_by_mau is True:
+            # If the user is already part of the MAU cohort
+            if user_id:
+                timestamp = yield self.store.user_last_seen_monthly_active(user_id)
+                if timestamp:
+                    return
+            # Else if there is no room in the MAU bucket, bail
             current_mau = yield self.store.get_monthly_active_count()
             if current_mau >= self.hs.config.max_mau_value:
                 raise AuthError(
-                    403, "MAU Limit Exceeded", errcode=Codes.MAU_LIMIT_EXCEEDED
+                    403, "Monthly Active User Limit Exceeded",
+                    admin_uri=self.hs.config.admin_uri,
+                    errcode=Codes.RESOURCE_LIMIT_EXCEED
                 )
diff --git a/synapse/api/errors.py b/synapse/api/errors.py
index 70400347bc..08f0cb5554 100644
--- a/synapse/api/errors.py
+++ b/synapse/api/errors.py
@@ -56,7 +56,7 @@ class Codes(object):
     SERVER_NOT_TRUSTED = "M_SERVER_NOT_TRUSTED"
     CONSENT_NOT_GIVEN = "M_CONSENT_NOT_GIVEN"
     CANNOT_LEAVE_SERVER_NOTICE_ROOM = "M_CANNOT_LEAVE_SERVER_NOTICE_ROOM"
-    MAU_LIMIT_EXCEEDED = "M_MAU_LIMIT_EXCEEDED"
+    RESOURCE_LIMIT_EXCEED = "M_RESOURCE_LIMIT_EXCEED"
     UNSUPPORTED_ROOM_VERSION = "M_UNSUPPORTED_ROOM_VERSION"
     INCOMPATIBLE_ROOM_VERSION = "M_INCOMPATIBLE_ROOM_VERSION"
 
@@ -224,11 +224,16 @@ class NotFoundError(SynapseError):
 
 class AuthError(SynapseError):
     """An error raised when there was a problem authorising an event."""
+    def __init__(self, code, msg, errcode=Codes.FORBIDDEN, admin_uri=None):
+        self.admin_uri = admin_uri
+        super(AuthError, self).__init__(code, msg, errcode=errcode)
 
-    def __init__(self, *args, **kwargs):
-        if "errcode" not in kwargs:
-            kwargs["errcode"] = Codes.FORBIDDEN
-        super(AuthError, self).__init__(*args, **kwargs)
+    def error_dict(self):
+        return cs_error(
+            self.msg,
+            self.errcode,
+            admin_uri=self.admin_uri,
+        )
 
 
 class EventSizeError(SynapseError):