[453] | 1 | /* dsa.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 | #ifdef HAVE_CONFIG_H
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| 24 | #include <config.h>
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| 25 | #endif
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| 26 |
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| 27 | #include <wolfssl/wolfcrypt/settings.h>
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| 28 |
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| 29 | #ifndef NO_DSA
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| 30 |
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| 31 | #include <wolfssl/wolfcrypt/random.h>
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| 32 | #include <wolfssl/wolfcrypt/integer.h>
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| 33 | #include <wolfssl/wolfcrypt/error-crypt.h>
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| 34 | #include <wolfssl/wolfcrypt/logging.h>
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| 35 | #include <wolfssl/wolfcrypt/sha.h>
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| 36 | #include <wolfssl/wolfcrypt/dsa.h>
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| 37 |
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| 38 | #ifdef NO_INLINE
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| 39 | #include <wolfssl/wolfcrypt/misc.h>
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| 40 | #else
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| 41 | #define WOLFSSL_MISC_INCLUDED
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| 42 | #include <wolfcrypt/src/misc.c>
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| 43 | #endif
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| 44 |
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| 45 | int wc_InitDsaKey(DsaKey* key)
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| 46 | {
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| 47 | if (key == NULL)
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| 48 | return BAD_FUNC_ARG;
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| 49 |
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| 50 | key->type = -1; /* haven't decided yet */
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| 51 | key->heap = NULL;
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| 52 |
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| 53 | return mp_init_multi(
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| 54 | /* public alloc parts */
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| 55 | &key->p,
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| 56 | &key->q,
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| 57 | &key->g,
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| 58 | &key->y,
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| 59 |
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| 60 | /* private alloc parts */
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| 61 | &key->x,
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| 62 | NULL
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| 63 | );
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| 64 | }
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| 65 |
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| 66 |
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| 67 | int wc_InitDsaKey_h(DsaKey* key, void* h)
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| 68 | {
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| 69 | int ret = wc_InitDsaKey(key);
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| 70 | if (ret == 0)
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| 71 | key->heap = h;
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| 72 |
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| 73 | return ret;
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| 74 | }
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| 75 |
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| 76 |
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| 77 | void wc_FreeDsaKey(DsaKey* key)
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| 78 | {
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| 79 | if (key == NULL)
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| 80 | return;
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| 81 |
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| 82 | if (key->type == DSA_PRIVATE)
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| 83 | mp_forcezero(&key->x);
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| 84 |
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| 85 | mp_clear(&key->x);
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| 86 | mp_clear(&key->y);
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| 87 | mp_clear(&key->g);
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| 88 | mp_clear(&key->q);
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| 89 | mp_clear(&key->p);
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| 90 | }
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| 91 |
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| 92 |
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| 93 | /* validate that (L,N) match allowed sizes from FIPS 186-4, Section 4.2.
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| 94 | * modLen - represents L, the size of p (prime modulus) in bits
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| 95 | * divLen - represents N, the size of q (prime divisor) in bits
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| 96 | * return 0 on success, -1 on error */
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| 97 | static int CheckDsaLN(int modLen, int divLen)
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| 98 | {
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| 99 | int ret = -1;
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| 100 |
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| 101 | switch (modLen) {
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| 102 | case 1024:
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| 103 | if (divLen == 160)
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| 104 | ret = 0;
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| 105 | break;
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| 106 | case 2048:
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| 107 | if (divLen == 224 || divLen == 256)
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| 108 | ret = 0;
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| 109 | break;
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| 110 | case 3072:
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| 111 | if (divLen == 256)
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| 112 | ret = 0;
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| 113 | break;
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| 114 | default:
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| 115 | break;
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| 116 | }
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| 117 |
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| 118 | return ret;
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| 119 | }
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| 120 |
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| 121 |
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| 122 | #ifdef WOLFSSL_KEY_GEN
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| 123 |
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| 124 | /* Create DSA key pair (&dsa->x, &dsa->y)
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| 125 | *
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| 126 | * Based on NIST FIPS 186-4,
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| 127 | * "B.1.1 Key Pair Generation Using Extra Random Bits"
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| 128 | *
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| 129 | * rng - pointer to initialized WC_RNG structure
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| 130 | * dsa - pointer to initialized DsaKey structure, will hold generated key
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| 131 | *
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| 132 | * return 0 on success, negative on error */
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| 133 | int wc_MakeDsaKey(WC_RNG *rng, DsaKey *dsa)
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| 134 | {
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| 135 | byte* cBuf;
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| 136 | int qSz, pSz, cSz, err;
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| 137 | mp_int tmpQ;
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| 138 |
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| 139 | if (rng == NULL || dsa == NULL)
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| 140 | return BAD_FUNC_ARG;
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| 141 |
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| 142 | qSz = mp_unsigned_bin_size(&dsa->q);
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| 143 | pSz = mp_unsigned_bin_size(&dsa->p);
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| 144 |
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| 145 | /* verify (L,N) pair bit lengths */
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| 146 | if (CheckDsaLN(pSz * WOLFSSL_BIT_SIZE, qSz * WOLFSSL_BIT_SIZE) != 0)
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| 147 | return BAD_FUNC_ARG;
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| 148 |
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| 149 | /* generate extra 64 bits so that bias from mod function is negligible */
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| 150 | cSz = qSz + (64 / WOLFSSL_BIT_SIZE);
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| 151 | cBuf = (byte*)XMALLOC(cSz, dsa->heap, DYNAMIC_TYPE_TMP_BUFFER);
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| 152 | if (cBuf == NULL) {
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| 153 | return MEMORY_E;
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| 154 | }
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| 155 |
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| 156 | if ((err = mp_init_multi(&dsa->x, &dsa->y, &tmpQ, NULL, NULL, NULL))
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| 157 | != MP_OKAY) {
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| 158 | XFREE(cBuf, dsa->heap, DYNAMIC_TYPE_TMP_BUFFER);
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| 159 | return err;
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| 160 | }
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| 161 |
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| 162 | do {
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| 163 | /* generate N+64 bits (c) from RBG into &dsa->x, making sure positive.
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| 164 | * Hash_DRBG uses SHA-256 which matches maximum
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| 165 | * requested_security_strength of (L,N) */
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| 166 | err = wc_RNG_GenerateBlock(rng, cBuf, cSz);
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| 167 | if (err != MP_OKAY) {
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| 168 | mp_clear(&dsa->x);
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| 169 | mp_clear(&dsa->y);
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| 170 | mp_clear(&tmpQ);
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| 171 | XFREE(cBuf, dsa->heap, DYNAMIC_TYPE_TMP_BUFFER);
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| 172 | return err;
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| 173 | }
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| 174 |
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| 175 | err = mp_read_unsigned_bin(&dsa->x, cBuf, cSz);
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| 176 | if (err != MP_OKAY) {
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| 177 | mp_clear(&dsa->x);
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| 178 | mp_clear(&dsa->y);
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| 179 | mp_clear(&tmpQ);
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| 180 | XFREE(cBuf, dsa->heap, DYNAMIC_TYPE_TMP_BUFFER);
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| 181 | return err;
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| 182 | }
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| 183 | } while (mp_cmp_d(&dsa->x, 1) != MP_GT);
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| 184 |
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| 185 | XFREE(cBuf, dsa->heap, DYNAMIC_TYPE_TMP_BUFFER);
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| 186 |
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| 187 | /* tmpQ = q - 1 */
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| 188 | if (err == MP_OKAY)
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| 189 | err = mp_copy(&dsa->q, &tmpQ);
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| 190 |
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| 191 | if (err == MP_OKAY)
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| 192 | err = mp_sub_d(&tmpQ, 1, &tmpQ);
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| 193 |
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| 194 | /* x = c mod (q-1), &dsa->x holds c */
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| 195 | if (err == MP_OKAY)
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| 196 | err = mp_mod(&dsa->x, &tmpQ, &dsa->x);
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| 197 |
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| 198 | /* x = c mod (q-1) + 1 */
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| 199 | if (err == MP_OKAY)
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| 200 | err = mp_add_d(&dsa->x, 1, &dsa->x);
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| 201 |
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| 202 | /* public key : y = g^x mod p */
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| 203 | if (err == MP_OKAY)
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| 204 | err = mp_exptmod_ex(&dsa->g, &dsa->x, dsa->q.used, &dsa->p, &dsa->y);
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| 205 |
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| 206 | if (err == MP_OKAY)
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| 207 | dsa->type = DSA_PRIVATE;
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| 208 |
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| 209 | if (err != MP_OKAY) {
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| 210 | mp_clear(&dsa->x);
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| 211 | mp_clear(&dsa->y);
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| 212 | }
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| 213 | mp_clear(&tmpQ);
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| 214 |
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| 215 | return err;
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| 216 | }
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| 217 |
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| 218 |
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| 219 | /* modulus_size in bits */
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| 220 | int wc_MakeDsaParameters(WC_RNG *rng, int modulus_size, DsaKey *dsa)
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| 221 | {
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| 222 | mp_int tmp, tmp2;
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| 223 | int err, msize, qsize,
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| 224 | loop_check_prime = 0,
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| 225 | check_prime = MP_NO;
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| 226 | unsigned char *buf;
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| 227 |
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| 228 | if (rng == NULL || dsa == NULL)
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| 229 | return BAD_FUNC_ARG;
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| 230 |
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| 231 | /* set group size in bytes from modulus size
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| 232 | * FIPS 186-4 defines valid values (1024, 160) (2048, 256) (3072, 256)
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| 233 | */
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| 234 | switch (modulus_size) {
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| 235 | case 1024:
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| 236 | qsize = 20;
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| 237 | break;
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| 238 | case 2048:
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| 239 | case 3072:
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| 240 | qsize = 32;
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| 241 | break;
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| 242 | default:
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| 243 | return BAD_FUNC_ARG;
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| 244 | }
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| 245 |
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| 246 | /* modulus size in bytes */
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| 247 | msize = modulus_size / WOLFSSL_BIT_SIZE;
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| 248 |
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| 249 | /* allocate ram */
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| 250 | buf = (unsigned char *)XMALLOC(msize - qsize,
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| 251 | dsa->heap, DYNAMIC_TYPE_TMP_BUFFER);
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| 252 | if (buf == NULL) {
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| 253 | return MEMORY_E;
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| 254 | }
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| 255 |
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| 256 | /* make a random string that will be multiplied against q */
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| 257 | err = wc_RNG_GenerateBlock(rng, buf, msize - qsize);
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| 258 | if (err != MP_OKAY) {
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| 259 | XFREE(buf, dsa->heap, DYNAMIC_TYPE_TMP_BUFFER);
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| 260 | return err;
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| 261 | }
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| 262 |
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| 263 | /* force magnitude */
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| 264 | buf[0] |= 0xC0;
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| 265 |
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| 266 | /* force even */
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| 267 | buf[msize - qsize - 1] &= ~1;
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| 268 |
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| 269 | if (mp_init_multi(&tmp2, &dsa->p, &dsa->q, 0, 0, 0) != MP_OKAY) {
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| 270 | mp_clear(&dsa->q);
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| 271 | XFREE(buf, dsa->heap, DYNAMIC_TYPE_TMP_BUFFER);
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| 272 | return MP_INIT_E;
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| 273 | }
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| 274 |
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| 275 | err = mp_read_unsigned_bin(&tmp2, buf, msize - qsize);
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| 276 | if (err != MP_OKAY) {
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| 277 | mp_clear(&dsa->q);
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| 278 | mp_clear(&dsa->p);
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| 279 | mp_clear(&tmp2);
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| 280 | XFREE(buf, dsa->heap, DYNAMIC_TYPE_TMP_BUFFER);
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| 281 | return err;
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| 282 | }
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| 283 | XFREE(buf, dsa->heap, DYNAMIC_TYPE_TMP_BUFFER);
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| 284 |
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| 285 | /* make our prime q */
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| 286 | err = mp_rand_prime(&dsa->q, qsize, rng, NULL);
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| 287 | if (err != MP_OKAY) {
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| 288 | mp_clear(&dsa->q);
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| 289 | mp_clear(&dsa->p);
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| 290 | mp_clear(&tmp2);
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| 291 | return err;
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| 292 | }
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| 293 |
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| 294 | /* p = random * q */
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| 295 | err = mp_mul(&dsa->q, &tmp2, &dsa->p);
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| 296 | if (err != MP_OKAY) {
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| 297 | mp_clear(&dsa->q);
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| 298 | mp_clear(&dsa->p);
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| 299 | mp_clear(&tmp2);
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| 300 | return err;
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| 301 | }
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| 302 |
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| 303 | /* p = random * q + 1, so q is a prime divisor of p-1 */
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| 304 | err = mp_add_d(&dsa->p, 1, &dsa->p);
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| 305 | if (err != MP_OKAY) {
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| 306 | mp_clear(&dsa->q);
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| 307 | mp_clear(&dsa->p);
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| 308 | mp_clear(&tmp2);
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| 309 | return err;
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| 310 | }
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| 311 |
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| 312 | if (mp_init(&tmp) != MP_OKAY) {
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| 313 | mp_clear(&dsa->q);
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| 314 | mp_clear(&dsa->p);
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| 315 | mp_clear(&tmp2);
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| 316 | return MP_INIT_E;
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| 317 | }
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| 318 |
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| 319 | /* tmp = 2q */
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| 320 | err = mp_add(&dsa->q, &dsa->q, &tmp);
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| 321 | if (err != MP_OKAY) {
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| 322 | mp_clear(&dsa->q);
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| 323 | mp_clear(&dsa->p);
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| 324 | mp_clear(&tmp);
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| 325 | mp_clear(&tmp2);
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| 326 | return err;
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| 327 | }
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| 328 |
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| 329 | /* loop until p is prime */
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| 330 | while (check_prime == MP_NO) {
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| 331 | err = mp_prime_is_prime_ex(&dsa->p, 8, &check_prime, rng);
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| 332 | if (err != MP_OKAY) {
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| 333 | mp_clear(&dsa->q);
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| 334 | mp_clear(&dsa->p);
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| 335 | mp_clear(&tmp);
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| 336 | mp_clear(&tmp2);
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| 337 | return err;
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| 338 | }
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| 339 |
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| 340 | if (check_prime != MP_YES) {
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| 341 | /* p += 2q */
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| 342 | err = mp_add(&tmp, &dsa->p, &dsa->p);
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| 343 | if (err != MP_OKAY) {
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| 344 | mp_clear(&dsa->q);
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| 345 | mp_clear(&dsa->p);
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| 346 | mp_clear(&tmp);
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| 347 | mp_clear(&tmp2);
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| 348 | return err;
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| 349 | }
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| 350 |
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| 351 | loop_check_prime++;
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| 352 | }
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| 353 | }
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| 354 |
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| 355 | /* tmp2 += (2*loop_check_prime)
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| 356 | * to have p = (q * tmp2) + 1 prime
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| 357 | */
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| 358 | if (loop_check_prime) {
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| 359 | err = mp_add_d(&tmp2, 2*loop_check_prime, &tmp2);
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| 360 | if (err != MP_OKAY) {
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| 361 | mp_clear(&dsa->q);
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| 362 | mp_clear(&dsa->p);
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| 363 | mp_clear(&tmp);
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| 364 | mp_clear(&tmp2);
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| 365 | return err;
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| 366 | }
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| 367 | }
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| 368 |
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| 369 | if (mp_init(&dsa->g) != MP_OKAY) {
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| 370 | mp_clear(&dsa->q);
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| 371 | mp_clear(&dsa->p);
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| 372 | mp_clear(&tmp);
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| 373 | mp_clear(&tmp2);
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| 374 | return MP_INIT_E;
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| 375 | }
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| 376 |
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| 377 | /* find a value g for which g^tmp2 != 1 */
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| 378 | if (mp_set(&dsa->g, 1) != MP_OKAY) {
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| 379 | mp_clear(&dsa->q);
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| 380 | mp_clear(&dsa->p);
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| 381 | mp_clear(&tmp);
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| 382 | mp_clear(&tmp2);
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| 383 | return MP_INIT_E;
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| 384 | }
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| 385 |
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| 386 | do {
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| 387 | err = mp_add_d(&dsa->g, 1, &dsa->g);
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| 388 | if (err != MP_OKAY) {
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| 389 | mp_clear(&dsa->q);
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| 390 | mp_clear(&dsa->p);
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| 391 | mp_clear(&dsa->g);
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| 392 | mp_clear(&tmp);
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| 393 | mp_clear(&tmp2);
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| 394 | return err;
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| 395 | }
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| 396 |
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| 397 | err = mp_exptmod(&dsa->g, &tmp2, &dsa->p, &tmp);
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| 398 | if (err != MP_OKAY) {
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| 399 | mp_clear(&dsa->q);
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| 400 | mp_clear(&dsa->p);
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| 401 | mp_clear(&dsa->g);
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| 402 | mp_clear(&tmp);
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| 403 | mp_clear(&tmp2);
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| 404 | return err;
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| 405 | }
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| 406 |
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| 407 | } while (mp_cmp_d(&tmp, 1) == MP_EQ);
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| 408 |
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| 409 | /* at this point tmp generates a group of order q mod p */
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| 410 | mp_exch(&tmp, &dsa->g);
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| 411 |
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| 412 | mp_clear(&tmp);
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| 413 | mp_clear(&tmp2);
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| 414 |
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| 415 | return MP_OKAY;
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| 416 | }
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| 417 | #endif /* WOLFSSL_KEY_GEN */
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| 418 |
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| 419 |
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| 420 | static int _DsaImportParamsRaw(DsaKey* dsa, const char* p, const char* q,
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| 421 | const char* g, int trusted, WC_RNG* rng)
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| 422 | {
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| 423 | int err;
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| 424 | word32 pSz, qSz;
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| 425 |
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| 426 | if (dsa == NULL || p == NULL || q == NULL || g == NULL)
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| 427 | return BAD_FUNC_ARG;
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| 428 |
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| 429 | /* read p */
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| 430 | err = mp_read_radix(&dsa->p, p, MP_RADIX_HEX);
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| 431 | if (err == MP_OKAY && !trusted) {
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| 432 | int isPrime = 1;
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| 433 | if (rng == NULL)
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| 434 | err = mp_prime_is_prime(&dsa->p, 8, &isPrime);
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| 435 | else
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| 436 | err = mp_prime_is_prime_ex(&dsa->p, 8, &isPrime, rng);
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| 437 |
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| 438 | if (err == MP_OKAY) {
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| 439 | if (!isPrime)
|
---|
| 440 | err = DH_CHECK_PUB_E;
|
---|
| 441 | }
|
---|
| 442 | }
|
---|
| 443 |
|
---|
| 444 | /* read q */
|
---|
| 445 | if (err == MP_OKAY)
|
---|
| 446 | err = mp_read_radix(&dsa->q, q, MP_RADIX_HEX);
|
---|
| 447 |
|
---|
| 448 | /* read g */
|
---|
| 449 | if (err == MP_OKAY)
|
---|
| 450 | err = mp_read_radix(&dsa->g, g, MP_RADIX_HEX);
|
---|
| 451 |
|
---|
| 452 | /* verify (L,N) pair bit lengths */
|
---|
| 453 | pSz = mp_unsigned_bin_size(&dsa->p);
|
---|
| 454 | qSz = mp_unsigned_bin_size(&dsa->q);
|
---|
| 455 |
|
---|
| 456 | if (CheckDsaLN(pSz * WOLFSSL_BIT_SIZE, qSz * WOLFSSL_BIT_SIZE) != 0) {
|
---|
| 457 | WOLFSSL_MSG("Invalid DSA p or q parameter size");
|
---|
| 458 | err = BAD_FUNC_ARG;
|
---|
| 459 | }
|
---|
| 460 |
|
---|
| 461 | if (err != MP_OKAY) {
|
---|
| 462 | mp_clear(&dsa->p);
|
---|
| 463 | mp_clear(&dsa->q);
|
---|
| 464 | mp_clear(&dsa->g);
|
---|
| 465 | }
|
---|
| 466 |
|
---|
| 467 | return err;
|
---|
| 468 | }
|
---|
| 469 |
|
---|
| 470 |
|
---|
| 471 | /* Import raw DSA parameters into DsaKey structure for use with wc_MakeDsaKey(),
|
---|
| 472 | * input parameters (p,q,g) should be represented as ASCII hex values.
|
---|
| 473 | *
|
---|
| 474 | * dsa - pointer to initialized DsaKey structure
|
---|
| 475 | * p - DSA (p) parameter, ASCII hex string
|
---|
| 476 | * pSz - length of p
|
---|
| 477 | * q - DSA (q) parameter, ASCII hex string
|
---|
| 478 | * qSz - length of q
|
---|
| 479 | * g - DSA (g) parameter, ASCII hex string
|
---|
| 480 | * gSz - length of g
|
---|
| 481 | *
|
---|
| 482 | * returns 0 on success, negative upon failure
|
---|
| 483 | */
|
---|
| 484 | int wc_DsaImportParamsRaw(DsaKey* dsa, const char* p, const char* q,
|
---|
| 485 | const char* g)
|
---|
| 486 | {
|
---|
| 487 | return _DsaImportParamsRaw(dsa, p, q, g, 1, NULL);
|
---|
| 488 | }
|
---|
| 489 |
|
---|
| 490 |
|
---|
| 491 | /* Import raw DSA parameters into DsaKey structure for use with wc_MakeDsaKey(),
|
---|
| 492 | * input parameters (p,q,g) should be represented as ASCII hex values. Check
|
---|
| 493 | * that the p value is probably prime.
|
---|
| 494 | *
|
---|
| 495 | * dsa - pointer to initialized DsaKey structure
|
---|
| 496 | * p - DSA (p) parameter, ASCII hex string
|
---|
| 497 | * pSz - length of p
|
---|
| 498 | * q - DSA (q) parameter, ASCII hex string
|
---|
| 499 | * qSz - length of q
|
---|
| 500 | * g - DSA (g) parameter, ASCII hex string
|
---|
| 501 | * gSz - length of g
|
---|
| 502 | * trusted - trust that p is OK
|
---|
| 503 | * rng - random number generator for the prime test
|
---|
| 504 | *
|
---|
| 505 | * returns 0 on success, negative upon failure
|
---|
| 506 | */
|
---|
| 507 | int wc_DsaImportParamsRawCheck(DsaKey* dsa, const char* p, const char* q,
|
---|
| 508 | const char* g, int trusted, WC_RNG* rng)
|
---|
| 509 | {
|
---|
| 510 | return _DsaImportParamsRaw(dsa, p, q, g, trusted, rng);
|
---|
| 511 | }
|
---|
| 512 |
|
---|
| 513 |
|
---|
| 514 | /* Export raw DSA parameters from DsaKey structure
|
---|
| 515 | *
|
---|
| 516 | * dsa - pointer to initialized DsaKey structure
|
---|
| 517 | * p - output location for DSA (p) parameter
|
---|
| 518 | * pSz - [IN/OUT] size of output buffer for p, size of p
|
---|
| 519 | * q - output location for DSA (q) parameter
|
---|
| 520 | * qSz - [IN/OUT] size of output buffer for q, size of q
|
---|
| 521 | * g - output location for DSA (g) parameter
|
---|
| 522 | * gSz - [IN/OUT] size of output buffer for g, size of g
|
---|
| 523 | *
|
---|
| 524 | * If p, q, and g pointers are all passed in as NULL, the function
|
---|
| 525 | * will set pSz, qSz, and gSz to the required output buffer sizes for p,
|
---|
| 526 | * q, and g. In this case, the function will return LENGTH_ONLY_E.
|
---|
| 527 | *
|
---|
| 528 | * returns 0 on success, negative upon failure
|
---|
| 529 | */
|
---|
| 530 | int wc_DsaExportParamsRaw(DsaKey* dsa, byte* p, word32* pSz,
|
---|
| 531 | byte* q, word32* qSz, byte* g, word32* gSz)
|
---|
| 532 | {
|
---|
| 533 | int err;
|
---|
| 534 | word32 pLen, qLen, gLen;
|
---|
| 535 |
|
---|
| 536 | if (dsa == NULL || pSz == NULL || qSz == NULL || gSz == NULL)
|
---|
| 537 | return BAD_FUNC_ARG;
|
---|
| 538 |
|
---|
| 539 | /* get required output buffer sizes */
|
---|
| 540 | pLen = mp_unsigned_bin_size(&dsa->p);
|
---|
| 541 | qLen = mp_unsigned_bin_size(&dsa->q);
|
---|
| 542 | gLen = mp_unsigned_bin_size(&dsa->g);
|
---|
| 543 |
|
---|
| 544 | /* return buffer sizes and LENGTH_ONLY_E if buffers are NULL */
|
---|
| 545 | if (p == NULL && q == NULL && g == NULL) {
|
---|
| 546 | *pSz = pLen;
|
---|
| 547 | *qSz = qLen;
|
---|
| 548 | *gSz = gLen;
|
---|
| 549 | return LENGTH_ONLY_E;
|
---|
| 550 | }
|
---|
| 551 |
|
---|
| 552 | if (p == NULL || q == NULL || g == NULL)
|
---|
| 553 | return BAD_FUNC_ARG;
|
---|
| 554 |
|
---|
| 555 | /* export p */
|
---|
| 556 | if (*pSz < pLen) {
|
---|
| 557 | WOLFSSL_MSG("Output buffer for DSA p parameter too small, "
|
---|
| 558 | "required size placed into pSz");
|
---|
| 559 | *pSz = pLen;
|
---|
| 560 | return BUFFER_E;
|
---|
| 561 | }
|
---|
| 562 | *pSz = pLen;
|
---|
| 563 | err = mp_to_unsigned_bin(&dsa->p, p);
|
---|
| 564 |
|
---|
| 565 | /* export q */
|
---|
| 566 | if (err == MP_OKAY) {
|
---|
| 567 | if (*qSz < qLen) {
|
---|
| 568 | WOLFSSL_MSG("Output buffer for DSA q parameter too small, "
|
---|
| 569 | "required size placed into qSz");
|
---|
| 570 | *qSz = qLen;
|
---|
| 571 | return BUFFER_E;
|
---|
| 572 | }
|
---|
| 573 | *qSz = qLen;
|
---|
| 574 | err = mp_to_unsigned_bin(&dsa->q, q);
|
---|
| 575 | }
|
---|
| 576 |
|
---|
| 577 | /* export g */
|
---|
| 578 | if (err == MP_OKAY) {
|
---|
| 579 | if (*gSz < gLen) {
|
---|
| 580 | WOLFSSL_MSG("Output buffer for DSA g parameter too small, "
|
---|
| 581 | "required size placed into gSz");
|
---|
| 582 | *gSz = gLen;
|
---|
| 583 | return BUFFER_E;
|
---|
| 584 | }
|
---|
| 585 | *gSz = gLen;
|
---|
| 586 | err = mp_to_unsigned_bin(&dsa->g, g);
|
---|
| 587 | }
|
---|
| 588 |
|
---|
| 589 | return err;
|
---|
| 590 | }
|
---|
| 591 |
|
---|
| 592 |
|
---|
| 593 | /* Export raw DSA key (x, y) from DsaKey structure
|
---|
| 594 | *
|
---|
| 595 | * dsa - pointer to initialized DsaKey structure
|
---|
| 596 | * x - output location for private key
|
---|
| 597 | * xSz - [IN/OUT] size of output buffer for x, size of x
|
---|
| 598 | * y - output location for public key
|
---|
| 599 | * ySz - [IN/OUT] size of output buffer for y, size of y
|
---|
| 600 | *
|
---|
| 601 | * If x and y pointers are all passed in as NULL, the function
|
---|
| 602 | * will set xSz and ySz to the required output buffer sizes for x
|
---|
| 603 | * and y. In this case, the function will return LENGTH_ONLY_E.
|
---|
| 604 | *
|
---|
| 605 | * returns 0 on success, negative upon failure
|
---|
| 606 | */
|
---|
| 607 | int wc_DsaExportKeyRaw(DsaKey* dsa, byte* x, word32* xSz, byte* y, word32* ySz)
|
---|
| 608 | {
|
---|
| 609 | int err;
|
---|
| 610 | word32 xLen, yLen;
|
---|
| 611 |
|
---|
| 612 | if (dsa == NULL || xSz == NULL || ySz == NULL)
|
---|
| 613 | return BAD_FUNC_ARG;
|
---|
| 614 |
|
---|
| 615 | /* get required output buffer sizes */
|
---|
| 616 | xLen = mp_unsigned_bin_size(&dsa->x);
|
---|
| 617 | yLen = mp_unsigned_bin_size(&dsa->y);
|
---|
| 618 |
|
---|
| 619 | /* return buffer sizes and LENGTH_ONLY_E if buffers are NULL */
|
---|
| 620 | if (x == NULL && y == NULL) {
|
---|
| 621 | *xSz = xLen;
|
---|
| 622 | *ySz = yLen;
|
---|
| 623 | return LENGTH_ONLY_E;
|
---|
| 624 | }
|
---|
| 625 |
|
---|
| 626 | if (x == NULL || y == NULL)
|
---|
| 627 | return BAD_FUNC_ARG;
|
---|
| 628 |
|
---|
| 629 | /* export x */
|
---|
| 630 | if (*xSz < xLen) {
|
---|
| 631 | WOLFSSL_MSG("Output buffer for DSA private key (x) too small, "
|
---|
| 632 | "required size placed into xSz");
|
---|
| 633 | *xSz = xLen;
|
---|
| 634 | return BUFFER_E;
|
---|
| 635 | }
|
---|
| 636 | *xSz = xLen;
|
---|
| 637 | err = mp_to_unsigned_bin(&dsa->x, x);
|
---|
| 638 |
|
---|
| 639 | /* export y */
|
---|
| 640 | if (err == MP_OKAY) {
|
---|
| 641 | if (*ySz < yLen) {
|
---|
| 642 | WOLFSSL_MSG("Output buffer to DSA public key (y) too small, "
|
---|
| 643 | "required size placed into ySz");
|
---|
| 644 | *ySz = yLen;
|
---|
| 645 | return BUFFER_E;
|
---|
| 646 | }
|
---|
| 647 | *ySz = yLen;
|
---|
| 648 | err = mp_to_unsigned_bin(&dsa->y, y);
|
---|
| 649 | }
|
---|
| 650 |
|
---|
| 651 | return err;
|
---|
| 652 | }
|
---|
| 653 |
|
---|
| 654 |
|
---|
| 655 | int wc_DsaSign(const byte* digest, byte* out, DsaKey* key, WC_RNG* rng)
|
---|
| 656 | {
|
---|
| 657 | mp_int k, kInv, r, s, H;
|
---|
| 658 | #ifndef WOLFSSL_MP_INVMOD_CONSTANT_TIME
|
---|
| 659 | mp_int b;
|
---|
| 660 | #endif
|
---|
| 661 | mp_int* qMinus1;
|
---|
| 662 | int ret = 0, sz;
|
---|
| 663 | byte buffer[DSA_HALF_SIZE];
|
---|
| 664 | byte* tmp; /* initial output pointer */
|
---|
| 665 |
|
---|
| 666 | if (digest == NULL || out == NULL || key == NULL || rng == NULL) {
|
---|
| 667 | return BAD_FUNC_ARG;
|
---|
| 668 | }
|
---|
| 669 |
|
---|
| 670 | tmp = out;
|
---|
| 671 |
|
---|
| 672 | sz = min((int)sizeof(buffer), mp_unsigned_bin_size(&key->q));
|
---|
| 673 |
|
---|
| 674 | #ifdef WOLFSSL_MP_INVMOD_CONSTANT_TIME
|
---|
| 675 | if (mp_init_multi(&k, &kInv, &r, &s, &H, 0) != MP_OKAY)
|
---|
| 676 | #else
|
---|
| 677 | if (mp_init_multi(&k, &kInv, &r, &s, &H, &b) != MP_OKAY)
|
---|
| 678 | #endif
|
---|
| 679 | {
|
---|
| 680 | return MP_INIT_E;
|
---|
| 681 | }
|
---|
| 682 | qMinus1 = &kInv;
|
---|
| 683 |
|
---|
| 684 | /* NIST FIPS 186-4: B.2.2
|
---|
| 685 | * Per-Message Secret Number Generation by Testing Candidates
|
---|
| 686 | * Generate k in range [1, q-1].
|
---|
| 687 | * Check that k is less than q-1: range [0, q-2].
|
---|
| 688 | * Add 1 to k: range [1, q-1].
|
---|
| 689 | */
|
---|
| 690 | if (mp_sub_d(&key->q, 1, qMinus1))
|
---|
| 691 | ret = MP_SUB_E;
|
---|
| 692 |
|
---|
| 693 | if (ret == 0) {
|
---|
| 694 | do {
|
---|
| 695 | /* Step 4: generate k */
|
---|
| 696 | ret = wc_RNG_GenerateBlock(rng, buffer, sz);
|
---|
| 697 |
|
---|
| 698 | /* Step 5 */
|
---|
| 699 | if (ret == 0 && mp_read_unsigned_bin(&k, buffer, sz) != MP_OKAY)
|
---|
| 700 | ret = MP_READ_E;
|
---|
| 701 |
|
---|
| 702 | /* k is a random numnber and it should be less than q-1
|
---|
| 703 | * if k greater than repeat
|
---|
| 704 | */
|
---|
| 705 | /* Step 6 */
|
---|
| 706 | } while (ret == 0 && mp_cmp(&k, qMinus1) != MP_LT);
|
---|
| 707 | }
|
---|
| 708 | /* Step 7 */
|
---|
| 709 | if (ret == 0 && mp_add_d(&k, 1, &k) != MP_OKAY)
|
---|
| 710 | ret = MP_MOD_E;
|
---|
| 711 |
|
---|
| 712 | #ifdef WOLFSSL_MP_INVMOD_CONSTANT_TIME
|
---|
| 713 | /* inverse k mod q */
|
---|
| 714 | if (ret == 0 && mp_invmod(&k, &key->q, &kInv) != MP_OKAY)
|
---|
| 715 | ret = MP_INVMOD_E;
|
---|
| 716 |
|
---|
| 717 | /* generate r, r = (g exp k mod p) mod q */
|
---|
| 718 | if (ret == 0 && mp_exptmod_ex(&key->g, &k, key->q.used, &key->p,
|
---|
| 719 | &r) != MP_OKAY) {
|
---|
| 720 | ret = MP_EXPTMOD_E;
|
---|
| 721 | }
|
---|
| 722 |
|
---|
| 723 | if (ret == 0 && mp_mod(&r, &key->q, &r) != MP_OKAY)
|
---|
| 724 | ret = MP_MOD_E;
|
---|
| 725 |
|
---|
| 726 | /* generate H from sha digest */
|
---|
| 727 | if (ret == 0 && mp_read_unsigned_bin(&H, digest,WC_SHA_DIGEST_SIZE) != MP_OKAY)
|
---|
| 728 | ret = MP_READ_E;
|
---|
| 729 |
|
---|
| 730 | /* generate s, s = (kInv * (H + x*r)) % q */
|
---|
| 731 | if (ret == 0 && mp_mul(&key->x, &r, &s) != MP_OKAY)
|
---|
| 732 | ret = MP_MUL_E;
|
---|
| 733 |
|
---|
| 734 | if (ret == 0 && mp_add(&s, &H, &s) != MP_OKAY)
|
---|
| 735 | ret = MP_ADD_E;
|
---|
| 736 |
|
---|
| 737 | if (ret == 0 && mp_mulmod(&s, &kInv, &key->q, &s) != MP_OKAY)
|
---|
| 738 | ret = MP_MULMOD_E;
|
---|
| 739 | #else
|
---|
| 740 | /* Blinding value
|
---|
| 741 | * Generate b in range [1, q-1].
|
---|
| 742 | */
|
---|
| 743 | if (ret == 0) {
|
---|
| 744 | do {
|
---|
| 745 | ret = wc_RNG_GenerateBlock(rng, buffer, sz);
|
---|
| 746 | if (ret == 0 && mp_read_unsigned_bin(&b, buffer, sz) != MP_OKAY)
|
---|
| 747 | ret = MP_READ_E;
|
---|
| 748 | } while (ret == 0 && mp_cmp(&b, qMinus1) != MP_LT);
|
---|
| 749 | }
|
---|
| 750 | if (ret == 0 && mp_add_d(&b, 1, &b) != MP_OKAY)
|
---|
| 751 | ret = MP_MOD_E;
|
---|
| 752 |
|
---|
| 753 | /* set H from sha digest */
|
---|
| 754 | if (ret == 0 && mp_read_unsigned_bin(&H, digest,
|
---|
| 755 | WC_SHA_DIGEST_SIZE) != MP_OKAY) {
|
---|
| 756 | ret = MP_READ_E;
|
---|
| 757 | }
|
---|
| 758 |
|
---|
| 759 | /* generate r, r = (g exp k mod p) mod q */
|
---|
| 760 | if (ret == 0 && mp_exptmod_ex(&key->g, &k, key->q.used, &key->p,
|
---|
| 761 | &r) != MP_OKAY) {
|
---|
| 762 | ret = MP_EXPTMOD_E;
|
---|
| 763 | }
|
---|
| 764 |
|
---|
| 765 | /* calculate s = (H + xr)/k
|
---|
| 766 | = b.(H/k.b + x.r/k.b) */
|
---|
| 767 |
|
---|
| 768 | /* k = k.b */
|
---|
| 769 | if (ret == 0 && mp_mulmod(&k, &b, &key->q, &k) != MP_OKAY)
|
---|
| 770 | ret = MP_MULMOD_E;
|
---|
| 771 |
|
---|
| 772 | /* kInv = 1/k.b mod q */
|
---|
| 773 | if (ret == 0 && mp_invmod(&k, &key->q, &kInv) != MP_OKAY)
|
---|
| 774 | ret = MP_INVMOD_E;
|
---|
| 775 |
|
---|
| 776 | if (ret == 0 && mp_mod(&r, &key->q, &r) != MP_OKAY)
|
---|
| 777 | ret = MP_MOD_E;
|
---|
| 778 |
|
---|
| 779 | /* s = x.r */
|
---|
| 780 | if (ret == 0 && mp_mul(&key->x, &r, &s) != MP_OKAY)
|
---|
| 781 | ret = MP_MUL_E;
|
---|
| 782 |
|
---|
| 783 | /* s = x.r/k.b */
|
---|
| 784 | if (ret == 0 && mp_mulmod(&s, &kInv, &key->q, &s) != MP_OKAY)
|
---|
| 785 | ret = MP_MULMOD_E;
|
---|
| 786 |
|
---|
| 787 | /* H = H/k.b */
|
---|
| 788 | if (ret == 0 && mp_mulmod(&H, &kInv, &key->q, &H) != MP_OKAY)
|
---|
| 789 | ret = MP_MULMOD_E;
|
---|
| 790 |
|
---|
| 791 | /* s = H/k.b + x.r/k.b
|
---|
| 792 | = (H + x.r)/k.b */
|
---|
| 793 | if (ret == 0 && mp_add(&s, &H, &s) != MP_OKAY)
|
---|
| 794 | ret = MP_ADD_E;
|
---|
| 795 |
|
---|
| 796 | /* s = b.(e + x.r)/k.b
|
---|
| 797 | = (e + x.r)/k */
|
---|
| 798 | if (ret == 0 && mp_mulmod(&s, &b, &key->q, &s) != MP_OKAY)
|
---|
| 799 | ret = MP_MULMOD_E;
|
---|
| 800 |
|
---|
| 801 | /* s = (e + x.r)/k */
|
---|
| 802 | if (ret == 0 && mp_mod(&s, &key->q, &s) != MP_OKAY)
|
---|
| 803 | ret = MP_MOD_E;
|
---|
| 804 | #endif
|
---|
| 805 |
|
---|
| 806 | /* detect zero r or s */
|
---|
| 807 | if (ret == 0 && (mp_iszero(&r) == MP_YES || mp_iszero(&s) == MP_YES))
|
---|
| 808 | ret = MP_ZERO_E;
|
---|
| 809 |
|
---|
| 810 | /* write out */
|
---|
| 811 | if (ret == 0) {
|
---|
| 812 | int rSz = mp_unsigned_bin_size(&r);
|
---|
| 813 | int sSz = mp_unsigned_bin_size(&s);
|
---|
| 814 |
|
---|
| 815 | while (rSz++ < DSA_HALF_SIZE) {
|
---|
| 816 | *out++ = 0x00; /* pad front with zeros */
|
---|
| 817 | }
|
---|
| 818 |
|
---|
| 819 | if (mp_to_unsigned_bin(&r, out) != MP_OKAY)
|
---|
| 820 | ret = MP_TO_E;
|
---|
| 821 | else {
|
---|
| 822 | out = tmp + DSA_HALF_SIZE; /* advance to s in output */
|
---|
| 823 | while (sSz++ < DSA_HALF_SIZE) {
|
---|
| 824 | *out++ = 0x00; /* pad front with zeros */
|
---|
| 825 | }
|
---|
| 826 | ret = mp_to_unsigned_bin(&s, out);
|
---|
| 827 | }
|
---|
| 828 | }
|
---|
| 829 |
|
---|
| 830 | ForceZero(buffer, sz);
|
---|
| 831 | mp_forcezero(&kInv);
|
---|
| 832 | mp_forcezero(&k);
|
---|
| 833 | #ifndef WOLFSSL_MP_INVMOD_CONSTANT_TIME
|
---|
| 834 | mp_forcezero(&b);
|
---|
| 835 |
|
---|
| 836 | mp_clear(&b);
|
---|
| 837 | #endif
|
---|
| 838 | mp_clear(&H);
|
---|
| 839 | mp_clear(&s);
|
---|
| 840 | mp_clear(&r);
|
---|
| 841 | mp_clear(&kInv);
|
---|
| 842 | mp_clear(&k);
|
---|
| 843 |
|
---|
| 844 | return ret;
|
---|
| 845 | }
|
---|
| 846 |
|
---|
| 847 |
|
---|
| 848 | int wc_DsaVerify(const byte* digest, const byte* sig, DsaKey* key, int* answer)
|
---|
| 849 | {
|
---|
| 850 | mp_int w, u1, u2, v, r, s;
|
---|
| 851 | int ret = 0;
|
---|
| 852 |
|
---|
| 853 | if (digest == NULL || sig == NULL || key == NULL || answer == NULL) {
|
---|
| 854 | return BAD_FUNC_ARG;
|
---|
| 855 | }
|
---|
| 856 |
|
---|
| 857 | if (mp_init_multi(&w, &u1, &u2, &v, &r, &s) != MP_OKAY)
|
---|
| 858 | return MP_INIT_E;
|
---|
| 859 |
|
---|
| 860 | /* set r and s from signature */
|
---|
| 861 | if (mp_read_unsigned_bin(&r, sig, DSA_HALF_SIZE) != MP_OKAY ||
|
---|
| 862 | mp_read_unsigned_bin(&s, sig + DSA_HALF_SIZE, DSA_HALF_SIZE) != MP_OKAY)
|
---|
| 863 | ret = MP_READ_E;
|
---|
| 864 |
|
---|
| 865 | /* sanity checks */
|
---|
| 866 | if (ret == 0) {
|
---|
| 867 | if (mp_iszero(&r) == MP_YES || mp_iszero(&s) == MP_YES ||
|
---|
| 868 | mp_cmp(&r, &key->q) != MP_LT || mp_cmp(&s, &key->q) != MP_LT) {
|
---|
| 869 | ret = MP_ZERO_E;
|
---|
| 870 | }
|
---|
| 871 | }
|
---|
| 872 |
|
---|
| 873 | /* put H into u1 from sha digest */
|
---|
| 874 | if (ret == 0 && mp_read_unsigned_bin(&u1,digest,WC_SHA_DIGEST_SIZE) != MP_OKAY)
|
---|
| 875 | ret = MP_READ_E;
|
---|
| 876 |
|
---|
| 877 | /* w = s invmod q */
|
---|
| 878 | if (ret == 0 && mp_invmod(&s, &key->q, &w) != MP_OKAY)
|
---|
| 879 | ret = MP_INVMOD_E;
|
---|
| 880 |
|
---|
| 881 | /* u1 = (H * w) % q */
|
---|
| 882 | if (ret == 0 && mp_mulmod(&u1, &w, &key->q, &u1) != MP_OKAY)
|
---|
| 883 | ret = MP_MULMOD_E;
|
---|
| 884 |
|
---|
| 885 | /* u2 = (r * w) % q */
|
---|
| 886 | if (ret == 0 && mp_mulmod(&r, &w, &key->q, &u2) != MP_OKAY)
|
---|
| 887 | ret = MP_MULMOD_E;
|
---|
| 888 |
|
---|
| 889 | /* verify v = ((g^u1 * y^u2) mod p) mod q */
|
---|
| 890 | if (ret == 0 && mp_exptmod(&key->g, &u1, &key->p, &u1) != MP_OKAY)
|
---|
| 891 | ret = MP_EXPTMOD_E;
|
---|
| 892 |
|
---|
| 893 | if (ret == 0 && mp_exptmod(&key->y, &u2, &key->p, &u2) != MP_OKAY)
|
---|
| 894 | ret = MP_EXPTMOD_E;
|
---|
| 895 |
|
---|
| 896 | if (ret == 0 && mp_mulmod(&u1, &u2, &key->p, &v) != MP_OKAY)
|
---|
| 897 | ret = MP_MULMOD_E;
|
---|
| 898 |
|
---|
| 899 | if (ret == 0 && mp_mod(&v, &key->q, &v) != MP_OKAY)
|
---|
| 900 | ret = MP_MULMOD_E;
|
---|
| 901 |
|
---|
| 902 | /* do they match */
|
---|
| 903 | if (ret == 0 && mp_cmp(&r, &v) == MP_EQ)
|
---|
| 904 | *answer = 1;
|
---|
| 905 | else
|
---|
| 906 | *answer = 0;
|
---|
| 907 |
|
---|
| 908 | mp_clear(&s);
|
---|
| 909 | mp_clear(&r);
|
---|
| 910 | mp_clear(&u1);
|
---|
| 911 | mp_clear(&u2);
|
---|
| 912 | mp_clear(&w);
|
---|
| 913 | mp_clear(&v);
|
---|
| 914 |
|
---|
| 915 | return ret;
|
---|
| 916 | }
|
---|
| 917 |
|
---|
| 918 |
|
---|
| 919 | #endif /* NO_DSA */
|
---|
| 920 |
|
---|