freebsd-skq/sys/libkern/timingsafe_bcmp.c

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2014-12-12 19:56:36 +00:00
/* $OpenBSD: timingsafe_bcmp.c,v 1.2 2014/06/10 04:16:57 deraadt Exp $ */
/*
* Copyright (c) 2010 Damien Miller. All rights reserved.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
* $FreeBSD$
*
*/
#include <sys/libkern.h>
int
timingsafe_bcmp(const void *b1, const void *b2, size_t n)
{
const unsigned char *p1 = b1, *p2 = b2;
int ret = 0;
for (; n > 0; n--)
ret |= *p1++ ^ *p2++;
return (ret != 0);
}