Add a maximum size for well-known lookups. (#8950)

1 files changed, 11 insertions, 2 deletions

diff --git a/synapse/http/matrixfederationclient.py b/synapse/http/matrixfederationclient.py
index c962994727..b261e078c4 100644
--- a/synapse/http/matrixfederationclient.py
+++ b/synapse/http/matrixfederationclient.py
@@ -37,16 +37,19 @@ from twisted.web.iweb import IBodyProducer, IResponse
 import synapse.metrics
 import synapse.util.retryutils
 from synapse.api.errors import (
+    Codes,
     FederationDeniedError,
     HttpResponseException,
     RequestSendFailed,
+    SynapseError,
 )
 from synapse.http import QuieterFileBodyProducer
 from synapse.http.client import (
     BlacklistingAgentWrapper,
     BlacklistingReactorWrapper,
+    BodyExceededMaxSize,
     encode_query_args,
-    readBodyToFile,
+    read_body_with_max_size,
 )
 from synapse.http.federation.matrix_federation_agent import MatrixFederationAgent
 from synapse.logging.context import make_deferred_yieldable
@@ -975,9 +978,15 @@ class MatrixFederationHttpClient:
         headers = dict(response.headers.getAllRawHeaders())
 
         try:
-            d = readBodyToFile(response, output_stream, max_size)
+            d = read_body_with_max_size(response, output_stream, max_size)
             d.addTimeout(self.default_timeout, self.reactor)
             length = await make_deferred_yieldable(d)
+        except BodyExceededMaxSize:
+            msg = "Requested file is too large > %r bytes" % (max_size,)
+            logger.warning(
+                "{%s} [%s] %s", request.txn_id, request.destination, msg,
+            )
+            SynapseError(502, msg, Codes.TOO_LARGE)
         except Exception as e:
             logger.warning(
                 "{%s} [%s] Error reading response: %s",