commit 75d36004665a637c5d0aa868a5d0b728b3d03d39
author Mark Dickinson <mdickinson@enthought.com> Sun Oct 28 10:00:46 2012 +0000
committer Mark Dickinson <mdickinson@enthought.com> Sun Oct 28 10:00:46 2012 +0000
tree eaae340a81386d4ca660f446cd69f586bf7b10a9
parent 08114d40e94fa97ac9a55b80b69dc269da904fcc

Issue #14700: Fix buggy overflow checks for large precision and width in new-style and old-style formatting.

Objects/stringobject.c

diff --git a/Objects/stringobject.c b/Objects/stringobject.c
index 39fa740..152ea21 100644
--- a/Objects/stringobject.c
+++ b/Objects/stringobject.c
@@ -4369,7 +4369,7 @@
                     c = Py_CHARMASK(*fmt++);
                     if (!isdigit(c))
                         break;
-                    if ((width*10) / 10 != width) {
+                    if (width > (PY_SSIZE_T_MAX - ((int)c - '0')) / 10) {
                         PyErr_SetString(
                             PyExc_ValueError,
                             "width too big");
@@ -4404,7 +4404,7 @@
                         c = Py_CHARMASK(*fmt++);
                         if (!isdigit(c))
                             break;
-                        if ((prec*10) / 10 != prec) {
+                        if (prec > (INT_MAX - ((int)c - '0')) / 10) {
                             PyErr_SetString(
                                 PyExc_ValueError,
                                 "prec too big");