[Python-checkins] cpython (2.7): fix overflow checking in PyString_Repr (closes #22519)

Tue Sep 30 01:11:12 CEST 2014

https://hg.python.org/cpython/rev/d9cd11eda152
changeset: 92636:d9cd11eda152
branch: 2.7
user: Benjamin Peterson <benjamin at python.org>
date: Mon Sep 29 19:01:18 2014 -0400
summary:
 fix overflow checking in PyString_Repr (closes #22519)
files:
 Misc/NEWS | 2 ++
 Objects/stringobject.c | 5 +++--
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -10,6 +10,8 @@
 Core and Builtins
 -----------------
 
+- Issue #22519: Fix overflow checking in PyString_Repr.
+
 - Issue #22518: Fix integer overflow issues in latin-1 encoding.
 
 - Issue #22379: Fix empty exception message in a TypeError raised in
diff --git a/Objects/stringobject.c b/Objects/stringobject.c
--- a/Objects/stringobject.c
+++ b/Objects/stringobject.c
@@ -926,13 +926,14 @@
 PyString_Repr(PyObject *obj, int smartquotes)
 {
 register PyStringObject* op = (PyStringObject*) obj;
- size_t newsize = 2 + 4 * Py_SIZE(op);
+ size_t newsize;
 PyObject *v;
- if (newsize > PY_SSIZE_T_MAX || newsize / 4 != Py_SIZE(op)) {
+ if (Py_SIZE(op) > (PY_SSIZE_T_MAX - 2)/4) {
 PyErr_SetString(PyExc_OverflowError,
 "string is too large to make repr");
 return NULL;
 }
+ newsize = 2 + 4*Py_SIZE(op);
 v = PyString_FromStringAndSize((char *)NULL, newsize);
 if (v == NULL) {
 return NULL;
-- 
Repository URL: https://hg.python.org/cpython
