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/* $OpenBSD: timingsafe.c,v 1.3 2014/06/21 22:57:15 tedu Exp $ */
/*
* Copyright (c) 2014 Google Inc.
*
* 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.
*/
#include <assert.h>
#include <stdlib.h>
#include <string.h>
#define ASSERT_EQ(a, b) assert((a) == (b))
enum {
N = 8
};
static unsigned char bufone[N], buftwo[N];
void
check()
{
int cmp = memcmp(bufone, buftwo, N);
/* Check for reflexivity. */
ASSERT_EQ(0, timingsafe_bcmp(bufone, bufone, N));
ASSERT_EQ(0, timingsafe_bcmp(buftwo, buftwo, N));
ASSERT_EQ(0, timingsafe_memcmp(bufone, bufone, N));
ASSERT_EQ(0, timingsafe_memcmp(buftwo, buftwo, N));
/* Check that timingsafe_bcmp returns 0 iff memcmp returns 0. */
ASSERT_EQ(cmp == 0, timingsafe_bcmp(bufone, buftwo, N) == 0);
/* Check that timingsafe_memcmp returns cmp... */
ASSERT_EQ(cmp < 0, timingsafe_memcmp(bufone, buftwo, N) < 0);
/* ... or -cmp if the argument order is swapped. */
ASSERT_EQ(-cmp < 0, timingsafe_memcmp(buftwo, bufone, N) < 0);
}
int
main()
{
int i, j;
for (i = 0; i < 10000; i++) {
arc4random_buf(bufone, N);
arc4random_buf(buftwo, N);
check();
for (j = 0; j < N; j++) {
buftwo[j] = bufone[j];
check();
}
}
return (0);
}
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