bpo-36946: Fix possible signed integer overflow when handling slices. (GH-13375)
The final addition (cur += step) may overflow, so use size_t for "cur".
"cur" is always positive (even for negative steps), so it is safe to use
size_t here.
Co-Authored-By: Martin Panter <vadmium+py@gmail.com>
diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index eaba583..0aa5e4a 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -13991,7 +13991,8 @@
i += PyUnicode_GET_LENGTH(self);
return unicode_getitem(self, i);
} else if (PySlice_Check(item)) {
- Py_ssize_t start, stop, step, slicelength, cur, i;
+ Py_ssize_t start, stop, step, slicelength, i;
+ size_t cur;
PyObject *result;
void *src_data, *dest_data;
int src_kind, dest_kind;