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merge 2.6 with hash randomization fix

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Benjamin Peterson 2012-02-20 21:44:56 -05:00
commit aee9dfba4a
26 changed files with 2503 additions and 140 deletions
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12
Objects/stringobject.c
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@ -1265,11 +1265,21 @@ string_hash(PyStringObject *a)
if (a->ob_shash != -1)
return a->ob_shash;
len = Py_SIZE(a);
/*
We make the hash of the empty string be 0, rather than using
(prefix ^ suffix), since this slightly obfuscates the hash secret
*/
if (len == 0) {
a->ob_shash = 0;
return 0;
}
p = (unsigned char *) a->ob_sval;
x = *p << 7;
x = _Py_HashSecret.prefix;
x ^= *p << 7;
while (--len >= 0)
x = (1000003*x) ^ *p++;
x ^= Py_SIZE(a);
x ^= _Py_HashSecret.suffix;
if (x == -1)
x = -2;
a->ob_shash = x;