1*08fca7a5SJohn-Mark Gurney /* $OpenBSD: timingsafe_bcmp.c,v 1.2 2014/06/10 04:16:57 deraadt Exp $ */
2*08fca7a5SJohn-Mark Gurney /*
3*08fca7a5SJohn-Mark Gurney * Copyright (c) 2010 Damien Miller. All rights reserved.
4*08fca7a5SJohn-Mark Gurney *
5*08fca7a5SJohn-Mark Gurney * Permission to use, copy, modify, and distribute this software for any
6*08fca7a5SJohn-Mark Gurney * purpose with or without fee is hereby granted, provided that the above
7*08fca7a5SJohn-Mark Gurney * copyright notice and this permission notice appear in all copies.
8*08fca7a5SJohn-Mark Gurney *
9*08fca7a5SJohn-Mark Gurney * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10*08fca7a5SJohn-Mark Gurney * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11*08fca7a5SJohn-Mark Gurney * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12*08fca7a5SJohn-Mark Gurney * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13*08fca7a5SJohn-Mark Gurney * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14*08fca7a5SJohn-Mark Gurney * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15*08fca7a5SJohn-Mark Gurney * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16*08fca7a5SJohn-Mark Gurney *
17*08fca7a5SJohn-Mark Gurney */
18*08fca7a5SJohn-Mark Gurney
19*08fca7a5SJohn-Mark Gurney #include <sys/libkern.h>
20*08fca7a5SJohn-Mark Gurney
21*08fca7a5SJohn-Mark Gurney int
timingsafe_bcmp(const void * b1,const void * b2,size_t n)22*08fca7a5SJohn-Mark Gurney timingsafe_bcmp(const void *b1, const void *b2, size_t n)
23*08fca7a5SJohn-Mark Gurney {
24*08fca7a5SJohn-Mark Gurney const unsigned char *p1 = b1, *p2 = b2;
25*08fca7a5SJohn-Mark Gurney int ret = 0;
26*08fca7a5SJohn-Mark Gurney
27*08fca7a5SJohn-Mark Gurney for (; n > 0; n--)
28*08fca7a5SJohn-Mark Gurney ret |= *p1++ ^ *p2++;
29*08fca7a5SJohn-Mark Gurney return (ret != 0);
30*08fca7a5SJohn-Mark Gurney }
31