From c3c9db89273fabc62ea1b48389d9a3000c1c03ae Mon Sep 17 00:00:00 2001
From: Jay Bosamiya <jaybosamiya@gmail.com>
Date: Sun, 18 Jun 2017 22:11:03 +0530
Subject: [PATCH] [2.7] bpo-30657: Check & prevent integer overflow in
PyString_DecodeEscape (#2174)
diff --git a/Objects/stringobject.c b/Objects/stringobject.c
index c78e19316a0..59d22e76946 100644
--- a/Objects/stringobject.c
+++ b/Objects/stringobject.c
@@ -612,7 +612,13 @@ PyObject *PyString_DecodeEscape(const char *s,
char *p, *buf;
const char *end;
PyObject *v;
- Py_ssize_t newlen = recode_encoding ? 4*len:len;
+ Py_ssize_t newlen;
+ /* Check for integer overflow */
+ if (recode_encoding && (len > PY_SSIZE_T_MAX / 4)) {
+ PyErr_SetString(PyExc_OverflowError, "string is too large");
+ return NULL;
+ }
+ newlen = recode_encoding ? 4*len:len;
v = PyString_FromStringAndSize((char *)NULL, newlen);
if (v == NULL)
return NULL;