[457] | 1 | /* wolfmath.c
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| 2 | *
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| 3 | * Copyright (C) 2006-2020 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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[464] | 90 | #if defined(HAVE_ECC) || defined(WOLFSSL_MP_COND_COPY)
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[457] | 91 | /* Conditionally copy a into b. Performed in constant time.
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| 92 | *
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| 93 | * a MP integer to copy.
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| 94 | * copy On 1, copy a into b. on 0 leave b unchanged.
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| 95 | * b MP integer to copy into.
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| 96 | * returns BAD_FUNC_ARG when a or b is NULL, MEMORY_E when growing b fails and
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| 97 | * MP_OKAY otherwise.
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| 98 | */
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| 99 | int mp_cond_copy(mp_int* a, int copy, mp_int* b)
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| 100 | {
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| 101 | int err = MP_OKAY;
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| 102 | int i;
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[464] | 103 | #if defined(SP_WORD_SIZE) && SP_WORD_SIZE == 8
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| 104 | unsigned int mask = (unsigned int)0 - copy;
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| 105 | #else
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[457] | 106 | mp_digit mask = (mp_digit)0 - copy;
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[464] | 107 | #endif
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[457] | 108 |
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| 109 | if (a == NULL || b == NULL)
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| 110 | err = BAD_FUNC_ARG;
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| 111 |
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| 112 | /* Ensure b has enough space to copy a into */
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| 113 | if (err == MP_OKAY)
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| 114 | err = mp_grow(b, a->used + 1);
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| 115 | if (err == MP_OKAY) {
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| 116 | /* When mask 0, b is unchanged2
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| 117 | * When mask all set, b ^ b ^ a = a
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| 118 | */
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| 119 | /* Conditionaly copy all digits and then number of used diigits.
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| 120 | * get_digit() returns 0 when index greater than available digit.
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| 121 | */
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| 122 | for (i = 0; i < a->used; i++) {
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| 123 | b->dp[i] ^= (get_digit(a, i) ^ get_digit(b, i)) & mask;
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| 124 | }
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| 125 | for (; i < b->used; i++) {
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| 126 | b->dp[i] ^= (get_digit(a, i) ^ get_digit(b, i)) & mask;
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| 127 | }
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| 128 | b->used ^= (a->used ^ b->used) & (int)mask;
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[464] | 129 | #if (!defined(WOLFSSL_SP_MATH) && !defined(WOLFSSL_SP_MATH_ALL)) || \
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| 130 | defined(WOLFSSL_SP_INT_NEGATIVE)
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| 131 | b->sign ^= (a->sign ^ b->sign) & (int)mask;
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| 132 | #endif
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[457] | 133 | }
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| 134 |
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| 135 | return err;
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| 136 | }
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[464] | 137 | #endif
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[457] | 138 |
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| 139 | #ifndef WC_NO_RNG
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| 140 | int get_rand_digit(WC_RNG* rng, mp_digit* d)
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| 141 | {
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| 142 | return wc_RNG_GenerateBlock(rng, (byte*)d, sizeof(mp_digit));
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| 143 | }
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| 144 |
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| 145 | #ifdef WC_RSA_BLINDING
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| 146 | int mp_rand(mp_int* a, int digits, WC_RNG* rng)
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| 147 | {
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| 148 | int ret = 0;
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| 149 | int cnt = digits * sizeof(mp_digit);
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| 150 | #if !defined(USE_FAST_MATH) && !defined(WOLFSSL_SP_MATH)
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| 151 | int i;
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| 152 | #endif
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| 153 |
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| 154 | if (rng == NULL) {
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| 155 | ret = MISSING_RNG_E;
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| 156 | }
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[464] | 157 | else if (a == NULL || digits == 0) {
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[457] | 158 | ret = BAD_FUNC_ARG;
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| 159 | }
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| 160 |
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| 161 | #if !defined(USE_FAST_MATH) && !defined(WOLFSSL_SP_MATH)
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| 162 | /* allocate space for digits */
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| 163 | if (ret == MP_OKAY) {
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| 164 | ret = mp_set_bit(a, digits * DIGIT_BIT - 1);
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| 165 | }
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| 166 | #else
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[464] | 167 | #if defined(WOLFSSL_SP_MATH) || defined(WOLFSSL_SP_MATH_ALL)
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[457] | 168 | if ((ret == MP_OKAY) && (digits > SP_INT_DIGITS))
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| 169 | #else
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| 170 | if ((ret == MP_OKAY) && (digits > FP_SIZE))
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| 171 | #endif
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| 172 | {
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| 173 | ret = BAD_FUNC_ARG;
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| 174 | }
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| 175 | if (ret == MP_OKAY) {
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| 176 | a->used = digits;
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| 177 | }
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| 178 | #endif
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| 179 | /* fill the data with random bytes */
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| 180 | if (ret == MP_OKAY) {
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| 181 | ret = wc_RNG_GenerateBlock(rng, (byte*)a->dp, cnt);
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| 182 | }
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| 183 | if (ret == MP_OKAY) {
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| 184 | #if !defined(USE_FAST_MATH) && !defined(WOLFSSL_SP_MATH)
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| 185 | /* Mask down each digit to only bits used */
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| 186 | for (i = 0; i < a->used; i++) {
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| 187 | a->dp[i] &= MP_MASK;
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| 188 | }
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| 189 | #endif
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| 190 | /* ensure top digit is not zero */
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| 191 | while ((ret == MP_OKAY) && (a->dp[a->used - 1] == 0)) {
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| 192 | ret = get_rand_digit(rng, &a->dp[a->used - 1]);
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| 193 | #if !defined(USE_FAST_MATH) && !defined(WOLFSSL_SP_MATH)
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| 194 | a->dp[a->used - 1] &= MP_MASK;
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| 195 | #endif
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| 196 | }
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| 197 | }
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| 198 |
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| 199 | return ret;
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| 200 | }
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| 201 | #endif /* WC_RSA_BLINDING */
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| 202 | #endif
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| 203 |
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[464] | 204 | #if defined(HAVE_ECC) || defined(WOLFSSL_EXPORT_INT)
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[457] | 205 | /* export an mp_int as unsigned char or hex string
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| 206 | * encType is WC_TYPE_UNSIGNED_BIN or WC_TYPE_HEX_STR
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| 207 | * return MP_OKAY on success */
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| 208 | int wc_export_int(mp_int* mp, byte* buf, word32* len, word32 keySz,
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| 209 | int encType)
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| 210 | {
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| 211 | int err;
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| 212 |
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| 213 | if (mp == NULL)
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| 214 | return BAD_FUNC_ARG;
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| 215 |
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| 216 | /* check buffer size */
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| 217 | if (*len < keySz) {
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| 218 | *len = keySz;
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| 219 | return BUFFER_E;
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| 220 | }
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| 221 |
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| 222 | *len = keySz;
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| 223 | XMEMSET(buf, 0, *len);
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| 224 |
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| 225 | if (encType == WC_TYPE_HEX_STR) {
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| 226 | #ifdef WC_MP_TO_RADIX
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| 227 | err = mp_tohex(mp, (char*)buf);
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| 228 | #else
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| 229 | err = NOT_COMPILED_IN;
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| 230 | #endif
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| 231 | }
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| 232 | else {
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| 233 | err = mp_to_unsigned_bin(mp, buf + (keySz - mp_unsigned_bin_size(mp)));
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| 234 | }
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| 235 |
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| 236 | return err;
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| 237 | }
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[464] | 238 | #endif
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[457] | 239 |
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| 240 |
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| 241 | #ifdef HAVE_WOLF_BIGINT
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| 242 | void wc_bigint_init(WC_BIGINT* a)
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| 243 | {
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| 244 | if (a != NULL) {
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| 245 | a->buf = NULL;
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| 246 | a->len = 0;
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| 247 | a->heap = NULL;
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| 248 | }
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| 249 | }
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| 250 |
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| 251 | int wc_bigint_alloc(WC_BIGINT* a, word32 sz)
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| 252 | {
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| 253 | int err = MP_OKAY;
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| 254 |
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| 255 | if (a == NULL)
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| 256 | return BAD_FUNC_ARG;
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| 257 |
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| 258 | if (sz > 0) {
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| 259 | if (a->buf && sz > a->len) {
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| 260 | wc_bigint_free(a);
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| 261 | }
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| 262 | if (a->buf == NULL) {
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| 263 | a->buf = (byte*)XMALLOC(sz, a->heap, DYNAMIC_TYPE_WOLF_BIGINT);
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| 264 | if (a->buf == NULL) {
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| 265 | err = MP_MEM;
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| 266 | }
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| 267 | }
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| 268 | else {
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| 269 | XMEMSET(a->buf, 0, sz);
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| 270 | }
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| 271 | }
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| 272 | a->len = sz;
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| 273 |
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| 274 | return err;
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| 275 | }
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| 276 |
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| 277 | /* assumes input is big endian format */
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| 278 | int wc_bigint_from_unsigned_bin(WC_BIGINT* a, const byte* in, word32 inlen)
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| 279 | {
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| 280 | int err;
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| 281 |
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| 282 | if (a == NULL || in == NULL || inlen == 0)
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| 283 | return BAD_FUNC_ARG;
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| 284 |
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| 285 | err = wc_bigint_alloc(a, inlen);
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| 286 | if (err == 0) {
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| 287 | XMEMCPY(a->buf, in, inlen);
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| 288 | }
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| 289 |
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| 290 | return err;
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| 291 | }
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| 292 |
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| 293 | int wc_bigint_to_unsigned_bin(WC_BIGINT* a, byte* out, word32* outlen)
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| 294 | {
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| 295 | word32 sz;
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| 296 |
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| 297 | if (a == NULL || out == NULL || outlen == NULL || *outlen == 0)
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| 298 | return BAD_FUNC_ARG;
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| 299 |
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| 300 | /* trim to fit into output buffer */
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| 301 | sz = a->len;
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| 302 | if (a->len > *outlen) {
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| 303 | WOLFSSL_MSG("wc_bigint_export: Truncating output");
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| 304 | sz = *outlen;
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| 305 | }
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| 306 |
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| 307 | if (a->buf) {
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| 308 | XMEMCPY(out, a->buf, sz);
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| 309 | }
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| 310 |
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| 311 | *outlen = sz;
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| 312 |
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| 313 | return MP_OKAY;
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| 314 | }
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| 315 |
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| 316 | void wc_bigint_zero(WC_BIGINT* a)
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| 317 | {
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| 318 | if (a && a->buf) {
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| 319 | ForceZero(a->buf, a->len);
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| 320 | }
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| 321 | }
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| 322 |
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| 323 | void wc_bigint_free(WC_BIGINT* a)
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| 324 | {
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| 325 | if (a) {
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| 326 | if (a->buf) {
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| 327 | XFREE(a->buf, a->heap, DYNAMIC_TYPE_WOLF_BIGINT);
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| 328 | }
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| 329 | a->buf = NULL;
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| 330 | a->len = 0;
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| 331 | }
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| 332 | }
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| 333 |
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| 334 | /* sz: make sure the buffer is at least that size and zero padded.
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| 335 | * A `sz == 0` will use the size of `src`.
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| 336 | * The calulcates sz is stored into dst->len in `wc_bigint_alloc`.
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| 337 | */
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| 338 | int wc_mp_to_bigint_sz(mp_int* src, WC_BIGINT* dst, word32 sz)
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| 339 | {
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| 340 | int err;
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| 341 | word32 x, y;
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| 342 |
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| 343 | if (src == NULL || dst == NULL)
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| 344 | return BAD_FUNC_ARG;
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| 345 |
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| 346 | /* get size of source */
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| 347 | x = mp_unsigned_bin_size(src);
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| 348 | if (sz < x)
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| 349 | sz = x;
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| 350 |
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| 351 | /* make sure destination is allocated and large enough */
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| 352 | err = wc_bigint_alloc(dst, sz);
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| 353 | if (err == MP_OKAY) {
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| 354 |
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| 355 | /* leading zero pad */
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| 356 | y = sz - x;
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| 357 | XMEMSET(dst->buf, 0, y);
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| 358 |
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| 359 | /* export src as unsigned bin to destination buf */
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| 360 | err = mp_to_unsigned_bin(src, dst->buf + y);
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| 361 | }
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| 362 |
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| 363 | return err;
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| 364 | }
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| 365 |
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| 366 | int wc_mp_to_bigint(mp_int* src, WC_BIGINT* dst)
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| 367 | {
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| 368 | if (src == NULL || dst == NULL)
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| 369 | return BAD_FUNC_ARG;
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| 370 |
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| 371 | return wc_mp_to_bigint_sz(src, dst, 0);
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| 372 | }
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| 373 |
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| 374 | int wc_bigint_to_mp(WC_BIGINT* src, mp_int* dst)
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| 375 | {
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| 376 | int err;
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| 377 |
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| 378 | if (src == NULL || dst == NULL)
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| 379 | return BAD_FUNC_ARG;
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| 380 |
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| 381 | if (src->buf == NULL)
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| 382 | return BAD_FUNC_ARG;
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| 383 |
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| 384 | err = mp_read_unsigned_bin(dst, src->buf, src->len);
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| 385 | wc_bigint_free(src);
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| 386 |
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| 387 | return err;
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| 388 | }
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| 389 | #endif /* HAVE_WOLF_BIGINT */
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| 390 |
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| 391 | #endif /* USE_FAST_MATH || !NO_BIG_INT */
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