mirror of
https://gitlab.isc.org/isc-projects/bind9
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82 lines
1.5 KiB
C
82 lines
1.5 KiB
C
/*
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* Copyright (C) 2013, 2015, 2016 Internet Systems Consortium, Inc. ("ISC")
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*/
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/*! \file */
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#include <config.h>
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#include <isc/safe.h>
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#include <isc/util.h>
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#ifdef WIN32
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#include <windows.h>
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#elif HAVE_EXPLICIT_BZERO
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#include <strings.h>
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#else
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#include <string.h>
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#endif
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#ifdef _MSC_VER
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#pragma optimize("", off)
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#endif
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isc_boolean_t
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isc_safe_memequal(const void *s1, const void *s2, size_t n) {
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isc_uint8_t acc = 0;
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if (n != 0U) {
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const isc_uint8_t *p1 = s1, *p2 = s2;
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do {
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acc |= *p1++ ^ *p2++;
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} while (--n != 0U);
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}
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return (ISC_TF(acc == 0));
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}
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int
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isc_safe_memcompare(const void *b1, const void *b2, size_t len) {
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const unsigned char *p1 = b1, *p2 = b2;
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size_t i;
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int res = 0, done = 0;
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for (i = 0; i < len; i++) {
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/* lt is -1 if p1[i] < p2[i]; else 0. */
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int lt = (p1[i] - p2[i]) >> CHAR_BIT;
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/* gt is -1 if p1[i] > p2[i]; else 0. */
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int gt = (p2[i] - p1[i]) >> CHAR_BIT;
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/* cmp is 1 if p1[i] > p2[i]; -1 if p1[i] < p2[i]; else 0. */
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int cmp = lt - gt;
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/* set res = cmp if !done. */
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res |= cmp & ~done;
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/* set done if p1[i] != p2[i]. */
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done |= lt | gt;
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}
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return (res);
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}
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void
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isc_safe_memwipe(void *ptr, size_t len) {
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if (ISC_UNLIKELY(ptr == NULL || len == 0))
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return;
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#ifdef WIN32
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SecureZeroMemory(ptr, len);
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#elif HAVE_EXPLICIT_BZERO
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explicit_bzero(ptr, len);
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#else
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memset(ptr, 0, len);
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#endif
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}
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