From: Benjamin Peterson <benjamin@python.org>
Date: Wed, 7 Sep 2016 00:58:25 +0000 (-0700)
Subject: make sure to not call memcpy with a NULL second argument
X-Git-Tag: v2.7.13rc1~166
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=d4d79003073a70e35fa7fd7f6d0eee7b95b6aed3;p=python

make sure to not call memcpy with a NULL second argument
---

diff --git a/Objects/listobject.c b/Objects/listobject.c
index c414620151..8ee86c6413 100644
--- a/Objects/listobject.c
+++ b/Objects/listobject.c
@@ -669,14 +669,17 @@ list_ass_slice(PyListObject *a, Py_ssize_t ilow, Py_ssize_t ihigh, PyObject *v)
     item = a->ob_item;
     /* recycle the items that we are about to remove */
     s = norig * sizeof(PyObject *);
-    if (s > sizeof(recycle_on_stack)) {
-        recycle = (PyObject **)PyMem_MALLOC(s);
-        if (recycle == NULL) {
-            PyErr_NoMemory();
-            goto Error;
+    /* If norig == 0, item might be NULL, in which case we may not memcpy from it. */
+    if (s) {
+        if (s > sizeof(recycle_on_stack)) {
+            recycle = (PyObject **)PyMem_MALLOC(s);
+            if (recycle == NULL) {
+                PyErr_NoMemory();
+                goto Error;
+            }
         }
+        memcpy(recycle, &item[ilow], s);
     }
-    memcpy(recycle, &item[ilow], s);
 
     if (d < 0) { /* Delete -d items */
         memmove(&item[ihigh+d], &item[ihigh],