[3.12] gh-126106: Fix NULL possible derefrence in Modules/_ssl.c (GH-126111) (#126117)

gh-126106: Fix `NULL` possible derefrence in `Modules/_ssl.c` (GH-126111)
(cherry picked from commit a64a1c9)

Co-authored-by: sobolevn <[email protected]>
Co-authored-by: Bénédikt Tran <[email protected]>

Author: 3 people

Misc/NEWS.d/next/Library/2024-10-29-10-58-52.gh-issue-126106.rlF798.rst

@@ -0,0 +1 @@
+Fixes a possible ``NULL`` pointer dereference in :mod:`ssl`.

Modules/_ssl.c

@@ -4951,14 +4951,14 @@ PySSLSession_dealloc(PySSLSession *self)
 static PyObject *
 PySSLSession_richcompare(PyObject *left, PyObject *right, int op)
 {
-    int result;
-    PyTypeObject *sesstype = ((PySSLSession*)left)->ctx->state->PySSLSession_Type;
-
     if (left == NULL || right == NULL) {
         PyErr_BadInternalCall();
         return NULL;
     }
 
+    int result;
+    PyTypeObject *sesstype = ((PySSLSession*)left)->ctx->state->PySSLSession_Type;
+
     if (!Py_IS_TYPE(left, sesstype) || !Py_IS_TYPE(right, sesstype)) {
         Py_RETURN_NOTIMPLEMENTED;
     }