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https://github.com/wolfSSL/wolfssl.git
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497313978f
1. Opt-out the wolfmath code if not using big integers. 2. Opt-in a few functions when using lean PSK and DTLS. 3. Add a couple (void)heap to hush the compiler for usused variables in lean PSK. 4. Add include limits.h to internal.h if CHAR_BIT isn't defined. This is mainly for DTLS with lean PSK.
108 lines
2.3 KiB
C
108 lines
2.3 KiB
C
/* wolfmath.c
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*
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* Copyright (C) 2006-2016 wolfSSL Inc.
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*
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* This file is part of wolfSSL.
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*
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* wolfSSL is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* wolfSSL is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335, USA
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*/
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/* common functions for either math library */
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif
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/* in case user set USE_FAST_MATH there */
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#include <wolfssl/wolfcrypt/settings.h>
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#ifdef USE_FAST_MATH
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#include <wolfssl/wolfcrypt/tfm.h>
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#else
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#include <wolfssl/wolfcrypt/integer.h>
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#endif
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#include <wolfssl/wolfcrypt/error-crypt.h>
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#include <wolfssl/wolfcrypt/logging.h>
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#if defined(USE_FAST_MATH) || !defined(NO_BIG_INT)
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int get_digit_count(mp_int* a)
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{
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if (a == NULL)
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return 0;
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return a->used;
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}
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mp_digit get_digit(mp_int* a, int n)
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{
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if (a == NULL)
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return 0;
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return (n >= a->used || n < 0) ? 0 : a->dp[n];
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}
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int get_rand_digit(WC_RNG* rng, mp_digit* d)
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{
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return wc_RNG_GenerateBlock(rng, (byte*)d, sizeof(mp_digit));
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}
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int mp_rand(mp_int* a, int digits, WC_RNG* rng)
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{
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int ret;
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mp_digit d;
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if (rng == NULL)
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return MISSING_RNG_E;
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if (a == NULL)
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return BAD_FUNC_ARG;
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mp_zero(a);
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if (digits <= 0) {
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return MP_OKAY;
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}
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/* first place a random non-zero digit */
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do {
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ret = get_rand_digit(rng, &d);
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if (ret != 0) {
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return ret;
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}
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} while (d == 0);
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if ((ret = mp_add_d(a, d, a)) != MP_OKAY) {
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return ret;
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}
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while (--digits > 0) {
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if ((ret = mp_lshd(a, 1)) != MP_OKAY) {
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return ret;
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}
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if ((ret = get_rand_digit(rng, &d)) != 0) {
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return ret;
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}
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if ((ret = mp_add_d(a, d, a)) != MP_OKAY) {
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return ret;
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}
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}
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return ret;
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}
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#endif
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