From: Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com>
Date: Tue, 13 Jan 2026 13:57:54 +0000 (+0100)
Subject: [3.14] gh-143249: Fix buffer leak when overlapped operation fails to start on windows... 
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4a191f9e704f41344f9d0167fd45e0cab357467a;p=thirdparty%2FPython%2Fcpython.git

[3.14] gh-143249: Fix buffer leak when overlapped operation fails to start on windows (GH-143250) (#143795)

gh-143249: Fix buffer leak when overlapped operation fails to start on windows (GH-143250)
(cherry picked from commit 103a384bfdeafc68ab39ea9bf8838a8b2eec83dd)

Co-authored-by: Yongtao Huang <yongtaoh2022@gmail.com>
---

diff --git a/Lib/test/test_asyncio/test_windows_utils.py b/Lib/test/test_asyncio/test_windows_utils.py
index 97f078ff911b..f9ee2f4f6815 100644
--- a/Lib/test/test_asyncio/test_windows_utils.py
+++ b/Lib/test/test_asyncio/test_windows_utils.py
@@ -129,5 +129,25 @@ class PopenTests(unittest.TestCase):
             pass
 
 
+class OverlappedRefleakTests(unittest.TestCase):
+
+    def test_wsasendto_failure(self):
+        ov = _overlapped.Overlapped()
+        buf = bytearray(4096)
+        with self.assertRaises(OSError):
+            ov.WSASendTo(0x1234, buf, 0, ("127.0.0.1", 1))
+
+    def test_wsarecvfrom_failure(self):
+        ov = _overlapped.Overlapped()
+        with self.assertRaises(OSError):
+            ov.WSARecvFrom(0x1234, 1024, 0)
+
+    def test_wsarecvfrominto_failure(self):
+        ov = _overlapped.Overlapped()
+        buf = bytearray(4096)
+        with self.assertRaises(OSError):
+            ov.WSARecvFromInto(0x1234, buf, len(buf), 0)
+
+
 if __name__ == '__main__':
     unittest.main()
diff --git a/Misc/NEWS.d/next/Library/2025-12-28-14-41-02.gh-issue-143249.K4vEp4.rst b/Misc/NEWS.d/next/Library/2025-12-28-14-41-02.gh-issue-143249.K4vEp4.rst
new file mode 100644
index 000000000000..d50d9e3db850
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2025-12-28-14-41-02.gh-issue-143249.K4vEp4.rst
@@ -0,0 +1 @@
+Fix possible buffer leaks in Windows overlapped I/O on error handling.
diff --git a/Modules/overlapped.c b/Modules/overlapped.c
index 29b7b356648a..09b57ce4b977 100644
--- a/Modules/overlapped.c
+++ b/Modules/overlapped.c
@@ -1806,7 +1806,7 @@ _overlapped_Overlapped_WSASendTo_impl(OverlappedObject *self, HANDLE handle,
         case ERROR_IO_PENDING:
             Py_RETURN_NONE;
         default:
-            self->type = TYPE_NOT_STARTED;
+            Overlapped_clear(self);
             return SetFromWindowsErr(err);
     }
 }
@@ -1873,7 +1873,7 @@ _overlapped_Overlapped_WSARecvFrom_impl(OverlappedObject *self,
     case ERROR_IO_PENDING:
         Py_RETURN_NONE;
     default:
-        self->type = TYPE_NOT_STARTED;
+        Overlapped_clear(self);
         return SetFromWindowsErr(err);
     }
 }
@@ -1940,7 +1940,7 @@ _overlapped_Overlapped_WSARecvFromInto_impl(OverlappedObject *self,
     case ERROR_IO_PENDING:
         Py_RETURN_NONE;
     default:
-        self->type = TYPE_NOT_STARTED;
+        Overlapped_clear(self);
         return SetFromWindowsErr(err);
     }
 }