[Python-checkins] cpython: Issue #1621: Overflow should not be possible in listextend()

[martin.panter]

https://hg.python.org/cpython/rev/eb6eafafdb44
changeset:   106145:eb6eafafdb44
user:        Martin Panter <vadmium+py at gmail.com>
date:        Sat Jan 14 06:30:37 2017 +0000
summary:
  Issue #1621: Overflow should not be possible in listextend()

files:
  Objects/listobject.c |  3 +++
  1 files changed, 3 insertions(+), 0 deletions(-)


diff --git a/Objects/listobject.c b/Objects/listobject.c
--- a/Objects/listobject.c
+++ b/Objects/listobject.c
@@ -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;

-- 
Repository URL: https://hg.python.org/cpython