changeset:   106145:eb6eafafdb44
user:        Martin Panter <vadmium+py@gmail.com>
date:        Sat Jan 14 06:30:37 2017 +0000
files:       Objects/listobject.c
description:
Issue #1621: Overflow should not be possible in listextend()


diff -r 0c6ea411af17 -r eb6eafafdb44 Objects/listobject.c
--- a/Objects/listobject.c	Sat Jan 14 06:29:32 2017 +0000
+++ b/Objects/listobject.c	Sat Jan 14 06:30:37 2017 +0000
@@ -804,6 +804,9 @@
             Py_RETURN_NONE;
         }
         m = Py_SIZE(self);
+        /* It should not be possible to allocate a list large enough to cause
+        an overflow on any relevant platform */
+        assert(m < PY_SSIZE_T_MAX - n);
         if (list_resize(self, m + n) < 0) {
             Py_DECREF(b);
             return NULL;