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Avoid possible undefined behaviour from signed overflow.

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This commit is contained in:
Mark Dickinson 2010-06-11 16:56:34 +00:00
parent 1c164a6f85
commit ab4096f2f9
2 changed files with 11 additions and 3 deletions
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9
Modules/_struct.c
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@ -1186,14 +1186,17 @@ prepare_s(PyStructObject *self)
if ('0' <= c && c <= '9') {
num = c - '0';
while ('0' <= (c = *s++) && c <= '9') {
x = num*10 + (c - '0');
if (x/10 != num) {
/* overflow-safe version of
if (num*10 + (c - '0') > PY_SSIZE_T_MAX) { ... } */
if (num >= PY_SSIZE_T_MAX / 10 && (
num > PY_SSIZE_T_MAX / 10 ||
(c - '0') > PY_SSIZE_T_MAX % 10)) {
PyErr_SetString(
StructError,
"overflow in item count");
return -1;
}
num = x;
num = num*10 + (c - '0');
}
if (c == '\0') {
PyErr_SetString(StructError,