[388] | 1 | /* wolfmath.c
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| 2 | *
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| 3 | * Copyright (C) 2006-2017 wolfSSL Inc.
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| 4 | *
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| 5 | * This file is part of wolfSSL.
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| 6 | *
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| 7 | * wolfSSL is free software; you can redistribute it and/or modify
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| 8 | * it under the terms of the GNU General Public License as published by
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| 9 | * the Free Software Foundation; either version 2 of the License, or
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| 10 | * (at your option) any later version.
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| 11 | *
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| 12 | * wolfSSL is distributed in the hope that it will be useful,
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| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 15 | * GNU General Public License for more details.
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| 16 | *
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| 17 | * You should have received a copy of the GNU General Public License
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| 18 | * along with this program; if not, write to the Free Software
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| 19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335, USA
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| 20 | */
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| 21 |
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| 22 |
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| 23 | /* common functions for either math library */
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| 24 |
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| 25 | #ifdef HAVE_CONFIG_H
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| 26 | #include <config.h>
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| 27 | #endif
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| 28 |
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| 29 | /* in case user set USE_FAST_MATH there */
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| 30 | #include <wolfssl/wolfcrypt/settings.h>
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| 31 |
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| 32 | #include <wolfssl/wolfcrypt/integer.h>
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| 33 |
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| 34 | #include <wolfssl/wolfcrypt/error-crypt.h>
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| 35 | #include <wolfssl/wolfcrypt/logging.h>
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| 36 |
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| 37 | #if defined(USE_FAST_MATH) || !defined(NO_BIG_INT)
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| 38 |
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| 39 | #ifdef WOLFSSL_ASYNC_CRYPT
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| 40 | #include <wolfssl/wolfcrypt/async.h>
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| 41 | #endif
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| 42 |
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| 43 | #ifdef NO_INLINE
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| 44 | #include <wolfssl/wolfcrypt/misc.h>
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| 45 | #else
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| 46 | #define WOLFSSL_MISC_INCLUDED
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| 47 | #include <wolfcrypt/src/misc.c>
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| 48 | #endif
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| 49 |
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| 50 |
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| 51 | #if !defined(WC_NO_CACHE_RESISTANT) && \
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| 52 | ((defined(HAVE_ECC) && defined(ECC_TIMING_RESISTANT)) || \
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| 53 | (defined(USE_FAST_MATH) && defined(TFM_TIMING_RESISTANT)))
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| 54 |
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| 55 | /* all off / all on pointer addresses for constant calculations */
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| 56 | /* ecc.c uses same table */
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| 57 | const wolfssl_word wc_off_on_addr[2] =
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| 58 | {
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| 59 | #if defined(WC_64BIT_CPU)
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| 60 | W64LIT(0x0000000000000000),
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| 61 | W64LIT(0xffffffffffffffff)
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| 62 | #elif defined(WC_16BIT_CPU)
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| 63 | 0x0000U,
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| 64 | 0xffffU
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| 65 | #else
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| 66 | /* 32 bit */
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| 67 | 0x00000000U,
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| 68 | 0xffffffffU
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| 69 | #endif
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| 70 | };
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| 71 | #endif
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| 72 |
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| 73 |
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| 74 | int get_digit_count(mp_int* a)
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| 75 | {
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| 76 | if (a == NULL)
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| 77 | return 0;
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| 78 |
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| 79 | return a->used;
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| 80 | }
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| 81 |
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| 82 | mp_digit get_digit(mp_int* a, int n)
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| 83 | {
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| 84 | if (a == NULL)
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| 85 | return 0;
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| 86 |
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| 87 | return (n >= a->used || n < 0) ? 0 : a->dp[n];
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| 88 | }
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| 89 |
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| 90 | #ifndef WC_NO_RNG
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| 91 | int get_rand_digit(WC_RNG* rng, mp_digit* d)
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| 92 | {
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| 93 | return wc_RNG_GenerateBlock(rng, (byte*)d, sizeof(mp_digit));
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| 94 | }
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| 95 |
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| 96 | #ifdef WC_RSA_BLINDING
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| 97 | int mp_rand(mp_int* a, int digits, WC_RNG* rng)
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| 98 | {
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| 99 | int ret = 0;
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| 100 | DECLARE_VAR(d, mp_digit, 1, rng ? rng->heap : NULL);
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| 101 |
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| 102 | if (rng == NULL) {
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| 103 | ret = MISSING_RNG_E; goto exit;
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| 104 | }
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| 105 |
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| 106 | if (a == NULL
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| 107 | #ifdef WOLFSSL_ASYNC_CRYPT
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| 108 | || d == NULL
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| 109 | #endif
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| 110 | ) {
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| 111 | ret = BAD_FUNC_ARG; goto exit;
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| 112 | }
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| 113 |
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| 114 | mp_zero(a);
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| 115 | if (digits <= 0) {
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| 116 | ret = MP_OKAY; goto exit;
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| 117 | }
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| 118 |
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| 119 | /* first place a random non-zero digit */
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| 120 | do {
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| 121 | ret = get_rand_digit(rng, d);
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| 122 | if (ret != 0) {
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| 123 | goto exit;
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| 124 | }
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| 125 | } while (*d == 0);
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| 126 |
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| 127 | if ((ret = mp_add_d(a, *d, a)) != MP_OKAY) {
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| 128 | goto exit;
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| 129 | }
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| 130 |
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| 131 | while (--digits > 0) {
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| 132 | if ((ret = mp_lshd(a, 1)) != MP_OKAY) {
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| 133 | goto exit;
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| 134 | }
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| 135 | if ((ret = get_rand_digit(rng, d)) != 0) {
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| 136 | goto exit;
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| 137 | }
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| 138 | if ((ret = mp_add_d(a, *d, a)) != MP_OKAY) {
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| 139 | goto exit;
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| 140 | }
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| 141 | }
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| 142 |
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| 143 | exit:
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| 144 | FREE_VAR(d, rng ? rng->heap : NULL);
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| 145 |
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| 146 | return ret;
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| 147 | }
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| 148 | #endif /* WC_RSA_BLINDING */
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| 149 | #endif
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| 150 |
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| 151 | /* export an mp_int as unsigned char or hex string
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| 152 | * encType is WC_TYPE_UNSIGNED_BIN or WC_TYPE_HEX_STR
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| 153 | * return MP_OKAY on success */
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| 154 | int wc_export_int(mp_int* mp, byte* buf, word32* len, word32 keySz,
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| 155 | int encType)
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| 156 | {
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| 157 | int err;
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| 158 |
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| 159 | if (mp == NULL)
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| 160 | return BAD_FUNC_ARG;
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| 161 |
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| 162 | /* check buffer size */
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| 163 | if (*len < keySz) {
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| 164 | *len = keySz;
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| 165 | return BUFFER_E;
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| 166 | }
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| 167 |
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| 168 | *len = keySz;
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| 169 | XMEMSET(buf, 0, *len);
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| 170 |
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| 171 | if (encType == WC_TYPE_HEX_STR) {
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| 172 | #ifdef WC_MP_TO_RADIX
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| 173 | err = mp_tohex(mp, (char*)buf);
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| 174 | #else
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| 175 | err = NOT_COMPILED_IN;
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| 176 | #endif
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| 177 | }
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| 178 | else {
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| 179 | err = mp_to_unsigned_bin(mp, buf + (keySz - mp_unsigned_bin_size(mp)));
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| 180 | }
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| 181 |
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| 182 | return err;
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| 183 | }
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| 184 |
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| 185 |
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| 186 | #ifdef HAVE_WOLF_BIGINT
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| 187 | void wc_bigint_init(WC_BIGINT* a)
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| 188 | {
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| 189 | if (a != NULL) {
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| 190 | a->buf = NULL;
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| 191 | a->len = 0;
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| 192 | a->heap = NULL;
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| 193 | }
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| 194 | }
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| 195 |
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| 196 | int wc_bigint_alloc(WC_BIGINT* a, word32 sz)
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| 197 | {
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| 198 | int err = MP_OKAY;
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| 199 |
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| 200 | if (a == NULL)
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| 201 | return BAD_FUNC_ARG;
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| 202 |
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| 203 | if (sz > 0) {
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| 204 | if (a->buf && sz > a->len) {
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| 205 | wc_bigint_free(a);
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| 206 | }
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| 207 | if (a->buf == NULL) {
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| 208 | a->buf = (byte*)XMALLOC(sz, a->heap, DYNAMIC_TYPE_WOLF_BIGINT);
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| 209 | }
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| 210 | if (a->buf == NULL) {
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| 211 | err = MP_MEM;
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| 212 | }
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| 213 | else {
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| 214 | XMEMSET(a->buf, 0, sz);
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| 215 | }
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| 216 | }
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| 217 | a->len = sz;
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| 218 |
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| 219 | return err;
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| 220 | }
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| 221 |
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| 222 | /* assumes input is big endian format */
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| 223 | int wc_bigint_from_unsigned_bin(WC_BIGINT* a, const byte* in, word32 inlen)
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| 224 | {
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| 225 | int err;
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| 226 |
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| 227 | if (a == NULL || in == NULL || inlen == 0)
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| 228 | return BAD_FUNC_ARG;
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| 229 |
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| 230 | err = wc_bigint_alloc(a, inlen);
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| 231 | if (err == 0) {
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| 232 | XMEMCPY(a->buf, in, inlen);
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| 233 | }
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| 234 |
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| 235 | return err;
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| 236 | }
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| 237 |
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| 238 | int wc_bigint_to_unsigned_bin(WC_BIGINT* a, byte* out, word32* outlen)
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| 239 | {
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| 240 | word32 sz;
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| 241 |
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| 242 | if (a == NULL || out == NULL || outlen == NULL || *outlen == 0)
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| 243 | return BAD_FUNC_ARG;
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| 244 |
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| 245 | /* trim to fit into output buffer */
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| 246 | sz = a->len;
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| 247 | if (a->len > *outlen) {
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| 248 | WOLFSSL_MSG("wc_bigint_export: Truncating output");
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| 249 | sz = *outlen;
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| 250 | }
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| 251 |
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| 252 | if (a->buf) {
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| 253 | XMEMCPY(out, a->buf, sz);
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| 254 | }
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| 255 |
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| 256 | *outlen = sz;
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| 257 |
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| 258 | return MP_OKAY;
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| 259 | }
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| 260 |
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| 261 | void wc_bigint_zero(WC_BIGINT* a)
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| 262 | {
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| 263 | if (a && a->buf) {
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| 264 | ForceZero(a->buf, a->len);
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| 265 | }
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| 266 | }
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| 267 |
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| 268 | void wc_bigint_free(WC_BIGINT* a)
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| 269 | {
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| 270 | if (a) {
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| 271 | if (a->buf) {
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| 272 | XFREE(a->buf, a->heap, DYNAMIC_TYPE_WOLF_BIGINT);
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| 273 | }
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| 274 | a->buf = NULL;
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| 275 | a->len = 0;
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| 276 | }
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| 277 | }
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| 278 |
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| 279 | /* sz: make sure the buffer is at least that size and zero padded.
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| 280 | * A `sz == 0` will use the size of `src`.
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| 281 | * The calulcates sz is stored into dst->len in `wc_bigint_alloc`.
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| 282 | */
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| 283 | int wc_mp_to_bigint_sz(mp_int* src, WC_BIGINT* dst, word32 sz)
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| 284 | {
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| 285 | int err;
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| 286 | word32 x, y;
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| 287 |
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| 288 | if (src == NULL || dst == NULL)
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| 289 | return BAD_FUNC_ARG;
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| 290 |
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| 291 | /* get size of source */
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| 292 | x = mp_unsigned_bin_size(src);
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| 293 | if (sz < x)
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| 294 | sz = x;
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| 295 |
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| 296 | /* make sure destination is allocated and large enough */
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| 297 | err = wc_bigint_alloc(dst, sz);
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| 298 | if (err == MP_OKAY) {
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| 299 |
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| 300 | /* leading zero pad */
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| 301 | y = sz - x;
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| 302 | XMEMSET(dst->buf, 0, y);
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| 303 |
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| 304 | /* export src as unsigned bin to destination buf */
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| 305 | err = mp_to_unsigned_bin(src, dst->buf + y);
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| 306 | }
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| 307 |
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| 308 | return err;
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| 309 | }
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| 310 |
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| 311 | int wc_mp_to_bigint(mp_int* src, WC_BIGINT* dst)
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| 312 | {
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| 313 | if (src == NULL || dst == NULL)
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| 314 | return BAD_FUNC_ARG;
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| 315 |
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| 316 | return wc_mp_to_bigint_sz(src, dst, 0);
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| 317 | }
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| 318 |
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| 319 | int wc_bigint_to_mp(WC_BIGINT* src, mp_int* dst)
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| 320 | {
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| 321 | int err;
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| 322 |
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| 323 | if (src == NULL || dst == NULL)
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| 324 | return BAD_FUNC_ARG;
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| 325 |
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| 326 | if (src->buf == NULL)
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| 327 | return BAD_FUNC_ARG;
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| 328 |
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| 329 | err = mp_read_unsigned_bin(dst, src->buf, src->len);
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| 330 | wc_bigint_free(src);
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| 331 |
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| 332 | return err;
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| 333 | }
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| 334 |
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| 335 | #endif /* HAVE_WOLF_BIGINT */
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| 336 |
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| 337 | #endif /* USE_FAST_MATH || !NO_BIG_INT */
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