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/*
* Copyright (C) Internet Systems Consortium, Inc. ("ISC")
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*
* See the COPYRIGHT file distributed with this work for additional
* information regarding copyright ownership.
*/
/*! \file */
#include <config.h>
#include <stdbool.h>
#include <isc/safe.h>
#include <isc/string.h>
#include <isc/util.h>
#ifdef WIN32
#include <windows.h>
#endif
#ifdef _MSC_VER
#pragma optimize("", off)
#endif
bool
isc_safe_memequal(const void *s1, const void *s2, size_t n) {
uint8_t acc = 0;
if (n != 0U) {
const uint8_t *p1 = s1, *p2 = s2;
do {
acc |= *p1++ ^ *p2++;
} while (--n != 0U);
}
return (acc == 0);
}
int
isc_safe_memcompare(const void *b1, const void *b2, size_t len) {
const unsigned char *p1 = b1, *p2 = b2;
size_t i;
int res = 0, done = 0;
for (i = 0; i < len; i++) {
/* lt is -1 if p1[i] < p2[i]; else 0. */
int lt = (p1[i] - p2[i]) >> CHAR_BIT;
/* gt is -1 if p1[i] > p2[i]; else 0. */
int gt = (p2[i] - p1[i]) >> CHAR_BIT;
/* cmp is 1 if p1[i] > p2[i]; -1 if p1[i] < p2[i]; else 0. */
int cmp = lt - gt;
/* set res = cmp if !done. */
res |= cmp & ~done;
/* set done if p1[i] != p2[i]. */
done |= lt | gt;
}
return (res);
}
void
isc_safe_memwipe(void *ptr, size_t len) {
if (ISC_UNLIKELY(ptr == NULL || len == 0))
return;
#ifdef WIN32
SecureZeroMemory(ptr, len);
#elif HAVE_EXPLICIT_BZERO
explicit_bzero(ptr, len);
#else
memset(ptr, 0, len);
#endif
}
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