Mercurial > cpython-lru_cache-weakref
diff Python/ceval.c @ 57533:8f6eee42f810 legacy-trunk
Issue #7406: Fix some occurrences of potential signed overflow in int
arithmetic.
| author | Mark Dickinson <dickinsm@gmail.com> |
|---|---|
| date | Wed, 02 Dec 2009 17:33:41 +0000 |
| parents | f594313b9364 |
| children | c2fdf25329ff |
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--- a/Python/ceval.c Wed Dec 02 14:27:11 2009 +0000 +++ b/Python/ceval.c Wed Dec 02 17:33:41 2009 +0000 @@ -1321,7 +1321,9 @@ register long a, b, i; a = PyInt_AS_LONG(v); b = PyInt_AS_LONG(w); - i = a + b; + /* cast to avoid undefined behaviour + on overflow */ + i = (long)((unsigned long)a + b); if ((i^a) < 0 && (i^b) < 0) goto slow_add; x = PyInt_FromLong(i); @@ -1351,7 +1353,9 @@ register long a, b, i; a = PyInt_AS_LONG(v); b = PyInt_AS_LONG(w); - i = a - b; + /* cast to avoid undefined behaviour + on overflow */ + i = (long)((unsigned long)a - b); if ((i^a) < 0 && (i^~b) < 0) goto slow_sub; x = PyInt_FromLong(i);