Issue #1621: Overflow should not be possible in listextend()

2017-01-14 06:30:37 +00:00 · 2017-01-14 06:30:37 +00:00 · 94b39ceb73
parent 5644729aa6
commit 94b39ceb73
1 changed files with 3 additions and 0 deletions
--- a/Objects/listobject.c
+++ b/Objects/listobject.c
@ -804,6 +804,9 @@ listextend(PyListObject *self, PyObject *b)
            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;