Issue #22435: Fix a file descriptor leak when SocketServer bind fails.

3 files changed, 18 insertions, 2 deletions

diff --git a/Lib/socketserver.py b/Lib/socketserver.py
index 3d58590..f1b0e4a 100644
--- a/Lib/socketserver.py
+++ b/Lib/socketserver.py
@@ -439,8 +439,12 @@ class TCPServer(BaseServer):
         self.socket = socket.socket(self.address_family,
                                     self.socket_type)
         if bind_and_activate:
-            self.server_bind()
-            self.server_activate()
+            try:
+                self.server_bind()
+                self.server_activate()
+            except:
+                self.server_close()
+                raise
 
     def server_bind(self):
         """Called by constructor to bind the socket.
diff --git a/Lib/test/test_socketserver.py b/Lib/test/test_socketserver.py
index 8e0fde4..f5d8d52 100644
--- a/Lib/test/test_socketserver.py
+++ b/Lib/test/test_socketserver.py
@@ -270,6 +270,16 @@ class SocketServerTest(unittest.TestCase):
             t.join()
             s.server_close()
 
+    def test_tcpserver_bind_leak(self):
+        # Issue #22435: the server socket wouldn't be closed if bind()/listen()
+        # failed.
+        # Create many servers for which bind() will fail, to see if this result
+        # in FD exhaustion.
+        for i in range(1024):
+            with self.assertRaises(OverflowError):
+                socketserver.TCPServer((HOST, -1),
+                                       socketserver.StreamRequestHandler)
+
 
 def test_main():
     if imp.lock_held():
diff --git a/Misc/NEWS b/Misc/NEWS
index 1453637..2408aea 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -174,6 +174,8 @@ Core and Builtins
 Library
 -------
 
+- Issue #22435: Fix a file descriptor leak when SocketServer bind fails.
+
 - Issue #13096: Fixed segfault in CTypes POINTER handling of large
   values.