Merge branch 'develop' into matrix-org-hotfixes

2 files changed, 48 insertions, 3 deletions

diff --git a/synapse/api/errors.py b/synapse/api/errors.py

index 6e40630ab6..4888c0ec4d 100644
--- a/synapse/api/errors.py
+++ b/synapse/api/errors.py
@@ -21,10 +21,10 @@ import typing
 from http import HTTPStatus
 from typing import Dict, List, Optional, Union
 
-from canonicaljson import json
-
 from twisted.web import http
 
+from synapse.util import json_decoder
+
 if typing.TYPE_CHECKING:
     from synapse.types import JsonDict
 
@@ -593,7 +593,7 @@ class HttpResponseException(CodeMessageException):
         # try to parse the body as json, to get better errcode/msg, but
         # default to M_UNKNOWN with the HTTP status as the error text
         try:
-            j = json.loads(self.response.decode("utf-8"))
+            j = json_decoder.decode(self.response.decode("utf-8"))
         except ValueError:
             j = {}
 
@@ -604,3 +604,11 @@ class HttpResponseException(CodeMessageException):
         errmsg = j.pop("error", self.msg)
 
         return ProxiedRequestError(self.code, errmsg, errcode, j)
+
+
+class ShadowBanError(Exception):
+    """
+    Raised when a shadow-banned user attempts to perform an action.
+
+    This should be caught and a proper "fake" success response sent to the user.
+    """
diff --git a/synapse/api/ratelimiting.py b/synapse/api/ratelimiting.py

index ec6b3a69a2..e62ae50ac2 100644
--- a/synapse/api/ratelimiting.py
+++ b/synapse/api/ratelimiting.py
@@ -17,6 +17,7 @@ from collections import OrderedDict
 from typing import Any, Optional, Tuple
 
 from synapse.api.errors import LimitExceededError
+from synapse.types import Requester
 from synapse.util import Clock
 
 
@@ -43,6 +44,42 @@ class Ratelimiter(object):
         #   * The rate_hz of this particular entry. This can vary per request
         self.actions = OrderedDict()  # type: OrderedDict[Any, Tuple[float, int, float]]
 
+    def can_requester_do_action(
+        self,
+        requester: Requester,
+        rate_hz: Optional[float] = None,
+        burst_count: Optional[int] = None,
+        update: bool = True,
+        _time_now_s: Optional[int] = None,
+    ) -> Tuple[bool, float]:
+        """Can the requester perform the action?
+
+        Args:
+            requester: The requester to key off when rate limiting. The user property
+                will be used.
+            rate_hz: The long term number of actions that can be performed in a second.
+                Overrides the value set during instantiation if set.
+            burst_count: How many actions that can be performed before being limited.
+                Overrides the value set during instantiation if set.
+            update: Whether to count this check as performing the action
+            _time_now_s: The current time. Optional, defaults to the current time according
+                to self.clock. Only used by tests.
+
+        Returns:
+            A tuple containing:
+                * A bool indicating if they can perform the action now
+                * The reactor timestamp for when the action can be performed next.
+                  -1 if rate_hz is less than or equal to zero
+        """
+        # Disable rate limiting of users belonging to any AS that is configured
+        # not to be rate limited in its registration file (rate_limited: true|false).
+        if requester.app_service and not requester.app_service.is_rate_limited():
+            return True, -1.0
+
+        return self.can_do_action(
+            requester.user.to_string(), rate_hz, burst_count, update, _time_now_s
+        )
+
     def can_do_action(
         self,
         key: Any,