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Diffstat (limited to 'lib/isc/safe.c')
-rw-r--r-- | lib/isc/safe.c | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/lib/isc/safe.c b/lib/isc/safe.c new file mode 100644 index 0000000..7a464b6 --- /dev/null +++ b/lib/isc/safe.c @@ -0,0 +1,83 @@ +/* + * 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 +} |