From a6f73f61147048187908299ae911c5ad498d813a Mon Sep 17 00:00:00 2001
From: "Miss Islington (bot)"
 <31488909+miss-islington@users.noreply.github.com>
Date: Wed, 17 Jan 2024 14:47:26 +0100
Subject: [PATCH] [3.9] bpo-37013: Fix the error handling in
 socket.if_indextoname() (GH-13503) (GH-112600)

* Fix a crash when pass UINT_MAX.
* Fix an integer overflow on 64-bit non-Windows platforms.
(cherry picked from commit 0daf555c6fb3feba77989382135a58215e1d70a5)

Co-authored-by: Zackery Spytz <zspytz@gmail.com>
---
 Lib/test/test_socket.py                       | 13 ++++++++++
 ...3-12-01-16-09-59.gh-issue-81194.FFad1c.rst |  3 +++
 Modules/socketmodule.c                        | 24 ++++++++++++-------
 3 files changed, 31 insertions(+), 9 deletions(-)
 create mode 100644 Misc/NEWS.d/next/Library/2023-12-01-16-09-59.gh-issue-81194.FFad1c.rst

diff --git a/Lib/test/test_socket.py b/Lib/test/test_socket.py
index 127d61cb6a8..043e5543889 100755
--- a/Lib/test/test_socket.py
+++ b/Lib/test/test_socket.py
@@ -1070,7 +1070,20 @@ def testInterfaceNameIndex(self):
                          'socket.if_indextoname() not available.')
     def testInvalidInterfaceIndexToName(self):
         self.assertRaises(OSError, socket.if_indextoname, 0)
+        self.assertRaises(OverflowError, socket.if_indextoname, -1)
+        self.assertRaises(OverflowError, socket.if_indextoname, 2**1000)
         self.assertRaises(TypeError, socket.if_indextoname, '_DEADBEEF')
+        if hasattr(socket, 'if_nameindex'):
+            indices = dict(socket.if_nameindex())
+            for index in indices:
+                index2 = index + 2**32
+                if index2 not in indices:
+                    with self.assertRaises((OverflowError, OSError)):
+                        socket.if_indextoname(index2)
+            for index in 2**32-1, 2**64-1:
+                if index not in indices:
+                    with self.assertRaises((OverflowError, OSError)):
+                        socket.if_indextoname(index)
 
     @unittest.skipUnless(hasattr(socket, 'if_nametoindex'),
                          'socket.if_nametoindex() not available.')
diff --git a/Misc/NEWS.d/next/Library/2023-12-01-16-09-59.gh-issue-81194.FFad1c.rst b/Misc/NEWS.d/next/Library/2023-12-01-16-09-59.gh-issue-81194.FFad1c.rst
new file mode 100644
index 00000000000..feb7a8643b9
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2023-12-01-16-09-59.gh-issue-81194.FFad1c.rst
@@ -0,0 +1,3 @@
+Fix a crash in :func:`socket.if_indextoname` with specific value (UINT_MAX).
+Fix an integer overflow in :func:`socket.if_indextoname` on 64-bit
+non-Windows platforms.
diff --git a/Modules/socketmodule.c b/Modules/socketmodule.c
index 133470f9b81..9e0223b1272 100644
--- a/Modules/socketmodule.c
+++ b/Modules/socketmodule.c
@@ -6890,17 +6890,23 @@ Returns the interface index corresponding to the interface name if_name.");
 static PyObject *
 socket_if_indextoname(PyObject *self, PyObject *arg)
 {
-#ifdef MS_WINDOWS
-    NET_IFINDEX index;
-#else
-    unsigned long index;
-#endif
-    char name[IF_NAMESIZE + 1];
-
-    index = PyLong_AsUnsignedLong(arg);
-    if (index == (unsigned long) -1)
+    unsigned long index_long = PyLong_AsUnsignedLong(arg);
+    if (index_long == (unsigned long) -1 && PyErr_Occurred()) {
         return NULL;
+    }
 
+#ifdef MS_WINDOWS
+    NET_IFINDEX index = (NET_IFINDEX)index_long;
+#else
+    unsigned int index = (unsigned int)index_long;
+#endif
+
+    if ((unsigned long)index != index_long) {
+        PyErr_SetString(PyExc_OverflowError, "index is too large");
+        return NULL;
+    }
+
+    char name[IF_NAMESIZE + 1];
     if (if_indextoname(index, name) == NULL) {
         PyErr_SetFromErrno(PyExc_OSError);
         return NULL;