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bpo-36791: Safer detection of integer overflow in sum(). (GH-13080)

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Serhiy Storchaka 2019-05-05 14:26:23 +03:00 • committed by GitHub
parent 88f07a804a
commit 29500737d4
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1 changed files with 5 additions and 3 deletions
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Python/bltinmodule.c
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@ -2375,9 +2375,11 @@ builtin_sum_impl(PyObject *module, PyObject *iterable, PyObject *start)
} }
if (PyLong_CheckExact(item)) { if (PyLong_CheckExact(item)) {
long b = PyLong_AsLongAndOverflow(item, &overflow); long b = PyLong_AsLongAndOverflow(item, &overflow);
long x = i_result + b; if (overflow == 0 &&
if (overflow == 0 && ((x^i_result) >= 0 || (x^b) >= 0)) { (i_result >= 0 ? (b <= LONG_MAX - i_result)
i_result = x; : (b >= LONG_MIN - i_result)))
{
i_result += b;
Py_DECREF(item); Py_DECREF(item);
continue; continue;
} }