pythonGH-123599: Match file: URL hostname against machine hostname in urllib

barneygale · barneygale · commit fc78d00e916b · 2025-04-14T18:18:39.000+01:00
In `_is_local_authority()`, return early if the authority matches the
machine hostname from `socket.gethostname()`, rather than resolving the
names and matching IP addresses.
diff --git a/Lib/urllib/request.py b/Lib/urllib/request.py
@@ -1485,6 +1485,13 @@ def open_local_file(self, req):
 def _is_local_authority(authority):
     if not authority or authority == 'localhost':
         return True
+    try:
+        hostname = socket.gethostname()
+    except socket.gaierror:
+        pass
+    else:
+        if authority == hostname:
+            return True
     try:
         address = socket.gethostbyname(authority)
     except (socket.gaierror, AttributeError):
