1 | /* dsa.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 | #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 |
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46 | enum {
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47 | DSA_HALF_SIZE = 20, /* r and s size */
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48 | DSA_SIG_SIZE = 40 /* signature size */
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49 | };
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50 |
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51 |
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52 |
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53 | int wc_InitDsaKey(DsaKey* key)
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54 | {
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55 | if (key == NULL)
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56 | return BAD_FUNC_ARG;
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57 |
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58 | key->type = -1; /* haven't decided yet */
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59 | key->heap = NULL;
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60 |
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61 | return mp_init_multi(
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62 | /* public alloc parts */
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63 | &key->p,
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64 | &key->q,
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65 | &key->g,
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66 | &key->y,
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67 |
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68 | /* private alloc parts */
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69 | &key->x,
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70 | NULL
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71 | );
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72 | }
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73 |
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74 |
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75 | int wc_InitDsaKey_h(DsaKey* key, void* h)
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76 | {
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77 | int ret = wc_InitDsaKey(key);
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78 | if (ret == 0)
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79 | key->heap = h;
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80 |
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81 | return ret;
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82 | }
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83 |
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84 |
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85 | void wc_FreeDsaKey(DsaKey* key)
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86 | {
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87 | if (key == NULL)
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88 | return;
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89 |
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90 | if (key->type == DSA_PRIVATE)
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91 | mp_forcezero(&key->x);
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92 |
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93 | mp_clear(&key->x);
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94 | mp_clear(&key->y);
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95 | mp_clear(&key->g);
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96 | mp_clear(&key->q);
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97 | mp_clear(&key->p);
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98 | }
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99 |
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100 |
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101 | /* validate that (L,N) match allowed sizes from FIPS 186-4, Section 4.2.
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102 | * modLen - represents L, the size of p (prime modulus) in bits
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103 | * divLen - represents N, the size of q (prime divisor) in bits
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104 | * return 0 on success, -1 on error */
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105 | static int CheckDsaLN(int modLen, int divLen)
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106 | {
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107 | int ret = -1;
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108 |
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109 | switch (modLen) {
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110 | case 1024:
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111 | if (divLen == 160)
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112 | ret = 0;
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113 | break;
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114 | case 2048:
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115 | if (divLen == 224 || divLen == 256)
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116 | ret = 0;
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117 | break;
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118 | case 3072:
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119 | if (divLen == 256)
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120 | ret = 0;
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121 | break;
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122 | default:
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123 | break;
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124 | }
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125 |
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126 | return ret;
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127 | }
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128 |
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129 |
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130 | #ifdef WOLFSSL_KEY_GEN
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131 |
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132 | /* Create DSA key pair (&dsa->x, &dsa->y)
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133 | *
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134 | * Based on NIST FIPS 186-4,
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135 | * "B.1.1 Key Pair Generation Using Extra Random Bits"
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136 | *
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137 | * rng - pointer to initialized WC_RNG structure
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138 | * dsa - pointer to initialized DsaKey structure, will hold generated key
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139 | *
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140 | * return 0 on success, negative on error */
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141 | int wc_MakeDsaKey(WC_RNG *rng, DsaKey *dsa)
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142 | {
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143 | byte* cBuf;
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144 | int qSz, pSz, cSz, err;
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145 | mp_int tmpQ;
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146 |
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147 | if (rng == NULL || dsa == NULL)
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148 | return BAD_FUNC_ARG;
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149 |
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150 | qSz = mp_unsigned_bin_size(&dsa->q);
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151 | pSz = mp_unsigned_bin_size(&dsa->p);
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152 |
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153 | /* verify (L,N) pair bit lengths */
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154 | if (CheckDsaLN(pSz * WOLFSSL_BIT_SIZE, qSz * WOLFSSL_BIT_SIZE) != 0)
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155 | return BAD_FUNC_ARG;
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156 |
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157 | /* generate extra 64 bits so that bias from mod function is negligible */
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158 | cSz = qSz + (64 / WOLFSSL_BIT_SIZE);
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159 | cBuf = (byte*)XMALLOC(cSz, dsa->heap, DYNAMIC_TYPE_TMP_BUFFER);
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160 | if (cBuf == NULL) {
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161 | return MEMORY_E;
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162 | }
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163 |
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164 | if ((err = mp_init_multi(&dsa->x, &dsa->y, &tmpQ, NULL, NULL, NULL))
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165 | != MP_OKAY) {
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166 | XFREE(cBuf, dsa->heap, DYNAMIC_TYPE_TMP_BUFFER);
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167 | return err;
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168 | }
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169 |
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170 | do {
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171 | /* generate N+64 bits (c) from RBG into &dsa->x, making sure positive.
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172 | * Hash_DRBG uses SHA-256 which matches maximum
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173 | * requested_security_strength of (L,N) */
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174 | err = wc_RNG_GenerateBlock(rng, cBuf, cSz);
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175 | if (err != MP_OKAY) {
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176 | mp_clear(&dsa->x);
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177 | mp_clear(&dsa->y);
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178 | mp_clear(&tmpQ);
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179 | XFREE(cBuf, dsa->heap, DYNAMIC_TYPE_TMP_BUFFER);
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180 | return err;
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181 | }
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182 |
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183 | err = mp_read_unsigned_bin(&dsa->x, cBuf, cSz);
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184 | if (err != MP_OKAY) {
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185 | mp_clear(&dsa->x);
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186 | mp_clear(&dsa->y);
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187 | mp_clear(&tmpQ);
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188 | XFREE(cBuf, dsa->heap, DYNAMIC_TYPE_TMP_BUFFER);
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189 | return err;
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190 | }
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191 | } while (mp_cmp_d(&dsa->x, 1) != MP_GT);
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192 |
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193 | XFREE(cBuf, dsa->heap, DYNAMIC_TYPE_TMP_BUFFER);
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194 |
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195 | /* tmpQ = q - 1 */
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196 | if (err == MP_OKAY)
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197 | err = mp_copy(&dsa->q, &tmpQ);
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198 |
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199 | if (err == MP_OKAY)
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200 | err = mp_sub_d(&tmpQ, 1, &tmpQ);
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201 |
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202 | /* x = c mod (q-1), &dsa->x holds c */
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203 | if (err == MP_OKAY)
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204 | err = mp_mod(&dsa->x, &tmpQ, &dsa->x);
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205 |
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206 | /* x = c mod (q-1) + 1 */
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207 | if (err == MP_OKAY)
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208 | err = mp_add_d(&dsa->x, 1, &dsa->x);
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209 |
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210 | /* public key : y = g^x mod p */
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211 | if (err == MP_OKAY)
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212 | err = mp_exptmod(&dsa->g, &dsa->x, &dsa->p, &dsa->y);
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213 |
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214 | if (err == MP_OKAY)
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215 | dsa->type = DSA_PRIVATE;
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216 |
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217 | if (err != MP_OKAY) {
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218 | mp_clear(&dsa->x);
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219 | mp_clear(&dsa->y);
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220 | }
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221 | mp_clear(&tmpQ);
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222 |
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223 | return err;
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224 | }
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225 |
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226 |
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227 | /* modulus_size in bits */
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228 | int wc_MakeDsaParameters(WC_RNG *rng, int modulus_size, DsaKey *dsa)
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229 | {
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230 | mp_int tmp, tmp2;
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231 | int err, msize, qsize,
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232 | loop_check_prime = 0,
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233 | check_prime = MP_NO;
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234 | unsigned char *buf;
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235 |
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236 | if (rng == NULL || dsa == NULL)
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237 | return BAD_FUNC_ARG;
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238 |
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239 | /* set group size in bytes from modulus size
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240 | * FIPS 186-4 defines valid values (1024, 160) (2048, 256) (3072, 256)
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241 | */
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242 | switch (modulus_size) {
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243 | case 1024:
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244 | qsize = 20;
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245 | break;
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246 | case 2048:
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247 | case 3072:
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248 | qsize = 32;
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249 | break;
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250 | default:
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251 | return BAD_FUNC_ARG;
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252 | }
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253 |
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254 | /* modulus size in bytes */
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255 | msize = modulus_size / WOLFSSL_BIT_SIZE;
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256 |
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257 | /* allocate ram */
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258 | buf = (unsigned char *)XMALLOC(msize - qsize,
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259 | dsa->heap, DYNAMIC_TYPE_TMP_BUFFER);
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260 | if (buf == NULL) {
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261 | return MEMORY_E;
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262 | }
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263 |
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264 | /* make a random string that will be multplied against q */
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265 | err = wc_RNG_GenerateBlock(rng, buf, msize - qsize);
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266 | if (err != MP_OKAY) {
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267 | XFREE(buf, dsa->heap, DYNAMIC_TYPE_TMP_BUFFER);
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268 | return err;
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269 | }
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270 |
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271 | /* force magnitude */
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272 | buf[0] |= 0xC0;
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273 |
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274 | /* force even */
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275 | buf[msize - qsize - 1] &= ~1;
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276 |
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277 | if (mp_init_multi(&tmp2, &dsa->p, &dsa->q, 0, 0, 0) != MP_OKAY) {
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278 | mp_clear(&dsa->q);
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279 | XFREE(buf, dsa->heap, DYNAMIC_TYPE_TMP_BUFFER);
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280 | return MP_INIT_E;
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281 | }
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282 |
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283 | err = mp_read_unsigned_bin(&tmp2, buf, msize - qsize);
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284 | if (err != MP_OKAY) {
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285 | mp_clear(&dsa->q);
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286 | mp_clear(&dsa->p);
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287 | mp_clear(&tmp2);
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288 | XFREE(buf, dsa->heap, DYNAMIC_TYPE_TMP_BUFFER);
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289 | return err;
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290 | }
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291 | XFREE(buf, dsa->heap, DYNAMIC_TYPE_TMP_BUFFER);
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292 |
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293 | /* make our prime q */
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294 | err = mp_rand_prime(&dsa->q, qsize, rng, NULL);
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295 | if (err != MP_OKAY) {
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296 | mp_clear(&dsa->q);
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297 | mp_clear(&dsa->p);
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298 | mp_clear(&tmp2);
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299 | return err;
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300 | }
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301 |
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302 | /* p = random * q */
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303 | err = mp_mul(&dsa->q, &tmp2, &dsa->p);
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304 | if (err != MP_OKAY) {
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305 | mp_clear(&dsa->q);
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306 | mp_clear(&dsa->p);
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307 | mp_clear(&tmp2);
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308 | return err;
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309 | }
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310 |
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311 | /* p = random * q + 1, so q is a prime divisor of p-1 */
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312 | err = mp_add_d(&dsa->p, 1, &dsa->p);
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313 | if (err != MP_OKAY) {
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314 | mp_clear(&dsa->q);
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315 | mp_clear(&dsa->p);
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316 | mp_clear(&tmp2);
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317 | return err;
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318 | }
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319 |
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320 | if (mp_init(&tmp) != MP_OKAY) {
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321 | mp_clear(&dsa->q);
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322 | mp_clear(&dsa->p);
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323 | mp_clear(&tmp2);
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324 | return MP_INIT_E;
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325 | }
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326 |
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327 | /* tmp = 2q */
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328 | err = mp_add(&dsa->q, &dsa->q, &tmp);
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329 | if (err != MP_OKAY) {
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330 | mp_clear(&dsa->q);
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331 | mp_clear(&dsa->p);
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332 | mp_clear(&tmp);
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333 | mp_clear(&tmp2);
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334 | return err;
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335 | }
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336 |
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337 | /* loop until p is prime */
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338 | while (check_prime == MP_NO) {
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339 | err = mp_prime_is_prime_ex(&dsa->p, 8, &check_prime, rng);
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340 | if (err != MP_OKAY) {
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341 | mp_clear(&dsa->q);
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342 | mp_clear(&dsa->p);
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343 | mp_clear(&tmp);
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344 | mp_clear(&tmp2);
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345 | return err;
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346 | }
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347 |
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348 | if (check_prime != MP_YES) {
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349 | /* p += 2q */
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350 | err = mp_add(&tmp, &dsa->p, &dsa->p);
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351 | if (err != MP_OKAY) {
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352 | mp_clear(&dsa->q);
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353 | mp_clear(&dsa->p);
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354 | mp_clear(&tmp);
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355 | mp_clear(&tmp2);
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356 | return err;
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357 | }
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358 |
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359 | loop_check_prime++;
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360 | }
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361 | }
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362 |
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363 | /* tmp2 += (2*loop_check_prime)
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364 | * to have p = (q * tmp2) + 1 prime
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365 | */
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366 | if (loop_check_prime) {
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367 | err = mp_add_d(&tmp2, 2*loop_check_prime, &tmp2);
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368 | if (err != MP_OKAY) {
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369 | mp_clear(&dsa->q);
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370 | mp_clear(&dsa->p);
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371 | mp_clear(&tmp);
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372 | mp_clear(&tmp2);
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373 | return err;
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374 | }
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375 | }
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376 |
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377 | if (mp_init(&dsa->g) != MP_OKAY) {
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378 | mp_clear(&dsa->q);
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379 | mp_clear(&dsa->p);
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380 | mp_clear(&tmp);
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381 | mp_clear(&tmp2);
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382 | return MP_INIT_E;
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383 | }
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384 |
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385 | /* find a value g for which g^tmp2 != 1 */
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386 | if (mp_set(&dsa->g, 1) != MP_OKAY) {
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387 | mp_clear(&dsa->q);
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388 | mp_clear(&dsa->p);
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389 | mp_clear(&tmp);
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390 | mp_clear(&tmp2);
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391 | return MP_INIT_E;
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392 | }
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393 |
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394 | do {
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395 | err = mp_add_d(&dsa->g, 1, &dsa->g);
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396 | if (err != MP_OKAY) {
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397 | mp_clear(&dsa->q);
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398 | mp_clear(&dsa->p);
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399 | mp_clear(&dsa->g);
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400 | mp_clear(&tmp);
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401 | mp_clear(&tmp2);
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402 | return err;
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403 | }
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404 |
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405 | err = mp_exptmod(&dsa->g, &tmp2, &dsa->p, &tmp);
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406 | if (err != MP_OKAY) {
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407 | mp_clear(&dsa->q);
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408 | mp_clear(&dsa->p);
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409 | mp_clear(&dsa->g);
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410 | mp_clear(&tmp);
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411 | mp_clear(&tmp2);
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412 | return err;
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413 | }
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414 |
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415 | } while (mp_cmp_d(&tmp, 1) == MP_EQ);
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416 |
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417 | /* at this point tmp generates a group of order q mod p */
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418 | mp_exch(&tmp, &dsa->g);
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419 |
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420 | mp_clear(&tmp);
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421 | mp_clear(&tmp2);
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422 |
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423 | return MP_OKAY;
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424 | }
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425 | #endif /* WOLFSSL_KEY_GEN */
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426 |
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427 |
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428 | static int _DsaImportParamsRaw(DsaKey* dsa, const char* p, const char* q,
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429 | const char* g, int trusted, WC_RNG* rng)
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430 | {
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431 | int err;
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432 | word32 pSz, qSz;
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433 |
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434 | if (dsa == NULL || p == NULL || q == NULL || g == NULL)
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435 | return BAD_FUNC_ARG;
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436 |
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437 | /* read p */
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438 | err = mp_read_radix(&dsa->p, p, MP_RADIX_HEX);
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439 | if (err == MP_OKAY && !trusted) {
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440 | int isPrime = 1;
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441 | if (rng == NULL)
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442 | err = mp_prime_is_prime(&dsa->p, 8, &isPrime);
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443 | else
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444 | err = mp_prime_is_prime_ex(&dsa->p, 8, &isPrime, rng);
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445 |
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446 | if (err == MP_OKAY) {
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447 | if (!isPrime)
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448 | err = DH_CHECK_PUB_E;
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449 | }
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450 | }
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451 |
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452 | /* read q */
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453 | if (err == MP_OKAY)
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454 | err = mp_read_radix(&dsa->q, q, MP_RADIX_HEX);
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455 |
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456 | /* read g */
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457 | if (err == MP_OKAY)
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458 | err = mp_read_radix(&dsa->g, g, MP_RADIX_HEX);
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459 |
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460 | /* verify (L,N) pair bit lengths */
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461 | pSz = mp_unsigned_bin_size(&dsa->p);
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462 | qSz = mp_unsigned_bin_size(&dsa->q);
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463 |
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464 | if (CheckDsaLN(pSz * WOLFSSL_BIT_SIZE, qSz * WOLFSSL_BIT_SIZE) != 0) {
|
---|
465 | WOLFSSL_MSG("Invalid DSA p or q parameter size");
|
---|
466 | err = BAD_FUNC_ARG;
|
---|
467 | }
|
---|
468 |
|
---|
469 | if (err != MP_OKAY) {
|
---|
470 | mp_clear(&dsa->p);
|
---|
471 | mp_clear(&dsa->q);
|
---|
472 | mp_clear(&dsa->g);
|
---|
473 | }
|
---|
474 |
|
---|
475 | return err;
|
---|
476 | }
|
---|
477 |
|
---|
478 |
|
---|
479 | /* Import raw DSA parameters into DsaKey structure for use with wc_MakeDsaKey(),
|
---|
480 | * input parameters (p,q,g) should be represented as ASCII hex values.
|
---|
481 | *
|
---|
482 | * dsa - pointer to initialized DsaKey structure
|
---|
483 | * p - DSA (p) parameter, ASCII hex string
|
---|
484 | * pSz - length of p
|
---|
485 | * q - DSA (q) parameter, ASCII hex string
|
---|
486 | * qSz - length of q
|
---|
487 | * g - DSA (g) parameter, ASCII hex string
|
---|
488 | * gSz - length of g
|
---|
489 | *
|
---|
490 | * returns 0 on success, negative upon failure
|
---|
491 | */
|
---|
492 | int wc_DsaImportParamsRaw(DsaKey* dsa, const char* p, const char* q,
|
---|
493 | const char* g)
|
---|
494 | {
|
---|
495 | return _DsaImportParamsRaw(dsa, p, q, g, 1, NULL);
|
---|
496 | }
|
---|
497 |
|
---|
498 |
|
---|
499 | /* Import raw DSA parameters into DsaKey structure for use with wc_MakeDsaKey(),
|
---|
500 | * input parameters (p,q,g) should be represented as ASCII hex values. Check
|
---|
501 | * that the p value is probably prime.
|
---|
502 | *
|
---|
503 | * dsa - pointer to initialized DsaKey structure
|
---|
504 | * p - DSA (p) parameter, ASCII hex string
|
---|
505 | * pSz - length of p
|
---|
506 | * q - DSA (q) parameter, ASCII hex string
|
---|
507 | * qSz - length of q
|
---|
508 | * g - DSA (g) parameter, ASCII hex string
|
---|
509 | * gSz - length of g
|
---|
510 | * trusted - trust that p is OK
|
---|
511 | * rng - random number generator for the prime test
|
---|
512 | *
|
---|
513 | * returns 0 on success, negative upon failure
|
---|
514 | */
|
---|
515 | int wc_DsaImportParamsRawCheck(DsaKey* dsa, const char* p, const char* q,
|
---|
516 | const char* g, int trusted, WC_RNG* rng)
|
---|
517 | {
|
---|
518 | return _DsaImportParamsRaw(dsa, p, q, g, trusted, rng);
|
---|
519 | }
|
---|
520 |
|
---|
521 |
|
---|
522 | /* Export raw DSA parameters from DsaKey structure
|
---|
523 | *
|
---|
524 | * dsa - pointer to initialized DsaKey structure
|
---|
525 | * p - output location for DSA (p) parameter
|
---|
526 | * pSz - [IN/OUT] size of output buffer for p, size of p
|
---|
527 | * q - output location for DSA (q) parameter
|
---|
528 | * qSz - [IN/OUT] size of output buffer for q, size of q
|
---|
529 | * g - output location for DSA (g) parameter
|
---|
530 | * gSz - [IN/OUT] size of output buffer for g, size of g
|
---|
531 | *
|
---|
532 | * If p, q, and g pointers are all passed in as NULL, the function
|
---|
533 | * will set pSz, qSz, and gSz to the required output buffer sizes for p,
|
---|
534 | * q, and g. In this case, the function will return LENGTH_ONLY_E.
|
---|
535 | *
|
---|
536 | * returns 0 on success, negative upon failure
|
---|
537 | */
|
---|
538 | int wc_DsaExportParamsRaw(DsaKey* dsa, byte* p, word32* pSz,
|
---|
539 | byte* q, word32* qSz, byte* g, word32* gSz)
|
---|
540 | {
|
---|
541 | int err;
|
---|
542 | word32 pLen, qLen, gLen;
|
---|
543 |
|
---|
544 | if (dsa == NULL || pSz == NULL || qSz == NULL || gSz == NULL)
|
---|
545 | return BAD_FUNC_ARG;
|
---|
546 |
|
---|
547 | /* get required output buffer sizes */
|
---|
548 | pLen = mp_unsigned_bin_size(&dsa->p);
|
---|
549 | qLen = mp_unsigned_bin_size(&dsa->q);
|
---|
550 | gLen = mp_unsigned_bin_size(&dsa->g);
|
---|
551 |
|
---|
552 | /* return buffer sizes and LENGTH_ONLY_E if buffers are NULL */
|
---|
553 | if (p == NULL && q == NULL && g == NULL) {
|
---|
554 | *pSz = pLen;
|
---|
555 | *qSz = qLen;
|
---|
556 | *gSz = gLen;
|
---|
557 | return LENGTH_ONLY_E;
|
---|
558 | }
|
---|
559 |
|
---|
560 | if (p == NULL || q == NULL || g == NULL)
|
---|
561 | return BAD_FUNC_ARG;
|
---|
562 |
|
---|
563 | /* export p */
|
---|
564 | if (*pSz < pLen) {
|
---|
565 | WOLFSSL_MSG("Output buffer for DSA p parameter too small, "
|
---|
566 | "required size placed into pSz");
|
---|
567 | *pSz = pLen;
|
---|
568 | return BUFFER_E;
|
---|
569 | }
|
---|
570 | *pSz = pLen;
|
---|
571 | err = mp_to_unsigned_bin(&dsa->p, p);
|
---|
572 |
|
---|
573 | /* export q */
|
---|
574 | if (err == MP_OKAY) {
|
---|
575 | if (*qSz < qLen) {
|
---|
576 | WOLFSSL_MSG("Output buffer for DSA q parameter too small, "
|
---|
577 | "required size placed into qSz");
|
---|
578 | *qSz = qLen;
|
---|
579 | return BUFFER_E;
|
---|
580 | }
|
---|
581 | *qSz = qLen;
|
---|
582 | err = mp_to_unsigned_bin(&dsa->q, q);
|
---|
583 | }
|
---|
584 |
|
---|
585 | /* export g */
|
---|
586 | if (err == MP_OKAY) {
|
---|
587 | if (*gSz < gLen) {
|
---|
588 | WOLFSSL_MSG("Output buffer for DSA g parameter too small, "
|
---|
589 | "required size placed into gSz");
|
---|
590 | *gSz = gLen;
|
---|
591 | return BUFFER_E;
|
---|
592 | }
|
---|
593 | *gSz = gLen;
|
---|
594 | err = mp_to_unsigned_bin(&dsa->g, g);
|
---|
595 | }
|
---|
596 |
|
---|
597 | return err;
|
---|
598 | }
|
---|
599 |
|
---|
600 |
|
---|
601 | /* Export raw DSA key (x, y) from DsaKey structure
|
---|
602 | *
|
---|
603 | * dsa - pointer to initialized DsaKey structure
|
---|
604 | * x - output location for private key
|
---|
605 | * xSz - [IN/OUT] size of output buffer for x, size of x
|
---|
606 | * y - output location for public key
|
---|
607 | * ySz - [IN/OUT] size of output buffer for y, size of y
|
---|
608 | *
|
---|
609 | * If x and y pointers are all passed in as NULL, the function
|
---|
610 | * will set xSz and ySz to the required output buffer sizes for x
|
---|
611 | * and y. In this case, the function will return LENGTH_ONLY_E.
|
---|
612 | *
|
---|
613 | * returns 0 on success, negative upon failure
|
---|
614 | */
|
---|
615 | int wc_DsaExportKeyRaw(DsaKey* dsa, byte* x, word32* xSz, byte* y, word32* ySz)
|
---|
616 | {
|
---|
617 | int err;
|
---|
618 | word32 xLen, yLen;
|
---|
619 |
|
---|
620 | if (dsa == NULL || xSz == NULL || ySz == NULL)
|
---|
621 | return BAD_FUNC_ARG;
|
---|
622 |
|
---|
623 | /* get required output buffer sizes */
|
---|
624 | xLen = mp_unsigned_bin_size(&dsa->x);
|
---|
625 | yLen = mp_unsigned_bin_size(&dsa->y);
|
---|
626 |
|
---|
627 | /* return buffer sizes and LENGTH_ONLY_E if buffers are NULL */
|
---|
628 | if (x == NULL && y == NULL) {
|
---|
629 | *xSz = xLen;
|
---|
630 | *ySz = yLen;
|
---|
631 | return LENGTH_ONLY_E;
|
---|
632 | }
|
---|
633 |
|
---|
634 | if (x == NULL || y == NULL)
|
---|
635 | return BAD_FUNC_ARG;
|
---|
636 |
|
---|
637 | /* export x */
|
---|
638 | if (*xSz < xLen) {
|
---|
639 | WOLFSSL_MSG("Output buffer for DSA private key (x) too small, "
|
---|
640 | "required size placed into xSz");
|
---|
641 | *xSz = xLen;
|
---|
642 | return BUFFER_E;
|
---|
643 | }
|
---|
644 | *xSz = xLen;
|
---|
645 | err = mp_to_unsigned_bin(&dsa->x, x);
|
---|
646 |
|
---|
647 | /* export y */
|
---|
648 | if (err == MP_OKAY) {
|
---|
649 | if (*ySz < yLen) {
|
---|
650 | WOLFSSL_MSG("Output buffer to DSA public key (y) too small, "
|
---|
651 | "required size placed into ySz");
|
---|
652 | *ySz = yLen;
|
---|
653 | return BUFFER_E;
|
---|
654 | }
|
---|
655 | *ySz = yLen;
|
---|
656 | err = mp_to_unsigned_bin(&dsa->y, y);
|
---|
657 | }
|
---|
658 |
|
---|
659 | return err;
|
---|
660 | }
|
---|
661 |
|
---|
662 |
|
---|
663 | int wc_DsaSign(const byte* digest, byte* out, DsaKey* key, WC_RNG* rng)
|
---|
664 | {
|
---|
665 | mp_int k, kInv, r, s, H;
|
---|
666 | int ret, sz;
|
---|
667 | byte buffer[DSA_HALF_SIZE];
|
---|
668 | byte* tmp; /* initial output pointer */
|
---|
669 |
|
---|
670 | if (digest == NULL || out == NULL || key == NULL || rng == NULL) {
|
---|
671 | return BAD_FUNC_ARG;
|
---|
672 | }
|
---|
673 |
|
---|
674 | tmp = out;
|
---|
675 |
|
---|
676 | sz = min((int)sizeof(buffer), mp_unsigned_bin_size(&key->q));
|
---|
677 |
|
---|
678 | if (mp_init_multi(&k, &kInv, &r, &s, &H, 0) != MP_OKAY)
|
---|
679 | return MP_INIT_E;
|
---|
680 |
|
---|
681 | do {
|
---|
682 | /* generate k */
|
---|
683 | ret = wc_RNG_GenerateBlock(rng, buffer, sz);
|
---|
684 | if (ret != 0)
|
---|
685 | return ret;
|
---|
686 |
|
---|
687 | buffer[0] |= 0x0C;
|
---|
688 |
|
---|
689 | if (mp_read_unsigned_bin(&k, buffer, sz) != MP_OKAY)
|
---|
690 | ret = MP_READ_E;
|
---|
691 |
|
---|
692 | /* k is a random numnber and it should be less than q
|
---|
693 | * if k greater than repeat
|
---|
694 | */
|
---|
695 | } while (mp_cmp(&k, &key->q) != MP_LT);
|
---|
696 |
|
---|
697 | if (ret == 0 && mp_cmp_d(&k, 1) != MP_GT)
|
---|
698 | ret = MP_CMP_E;
|
---|
699 |
|
---|
700 | /* inverse k mod q */
|
---|
701 | if (ret == 0 && mp_invmod(&k, &key->q, &kInv) != MP_OKAY)
|
---|
702 | ret = MP_INVMOD_E;
|
---|
703 |
|
---|
704 | /* generate r, r = (g exp k mod p) mod q */
|
---|
705 | if (ret == 0 && mp_exptmod(&key->g, &k, &key->p, &r) != MP_OKAY)
|
---|
706 | ret = MP_EXPTMOD_E;
|
---|
707 |
|
---|
708 | if (ret == 0 && mp_mod(&r, &key->q, &r) != MP_OKAY)
|
---|
709 | ret = MP_MOD_E;
|
---|
710 |
|
---|
711 | /* generate H from sha digest */
|
---|
712 | if (ret == 0 && mp_read_unsigned_bin(&H, digest,WC_SHA_DIGEST_SIZE) != MP_OKAY)
|
---|
713 | ret = MP_READ_E;
|
---|
714 |
|
---|
715 | /* generate s, s = (kInv * (H + x*r)) % q */
|
---|
716 | if (ret == 0 && mp_mul(&key->x, &r, &s) != MP_OKAY)
|
---|
717 | ret = MP_MUL_E;
|
---|
718 |
|
---|
719 | if (ret == 0 && mp_add(&s, &H, &s) != MP_OKAY)
|
---|
720 | ret = MP_ADD_E;
|
---|
721 |
|
---|
722 | if (ret == 0 && mp_mulmod(&s, &kInv, &key->q, &s) != MP_OKAY)
|
---|
723 | ret = MP_MULMOD_E;
|
---|
724 |
|
---|
725 | /* detect zero r or s */
|
---|
726 | if (ret == 0 && (mp_iszero(&r) == MP_YES || mp_iszero(&s) == MP_YES))
|
---|
727 | ret = MP_ZERO_E;
|
---|
728 |
|
---|
729 | /* write out */
|
---|
730 | if (ret == 0) {
|
---|
731 | int rSz = mp_unsigned_bin_size(&r);
|
---|
732 | int sSz = mp_unsigned_bin_size(&s);
|
---|
733 |
|
---|
734 | while (rSz++ < DSA_HALF_SIZE) {
|
---|
735 | *out++ = 0x00; /* pad front with zeros */
|
---|
736 | }
|
---|
737 |
|
---|
738 | if (mp_to_unsigned_bin(&r, out) != MP_OKAY)
|
---|
739 | ret = MP_TO_E;
|
---|
740 | else {
|
---|
741 | out = tmp + DSA_HALF_SIZE; /* advance to s in output */
|
---|
742 | while (sSz++ < DSA_HALF_SIZE) {
|
---|
743 | *out++ = 0x00; /* pad front with zeros */
|
---|
744 | }
|
---|
745 | ret = mp_to_unsigned_bin(&s, out);
|
---|
746 | }
|
---|
747 | }
|
---|
748 |
|
---|
749 | mp_clear(&H);
|
---|
750 | mp_clear(&s);
|
---|
751 | mp_clear(&r);
|
---|
752 | mp_clear(&kInv);
|
---|
753 | mp_clear(&k);
|
---|
754 |
|
---|
755 | return ret;
|
---|
756 | }
|
---|
757 |
|
---|
758 |
|
---|
759 | int wc_DsaVerify(const byte* digest, const byte* sig, DsaKey* key, int* answer)
|
---|
760 | {
|
---|
761 | mp_int w, u1, u2, v, r, s;
|
---|
762 | int ret = 0;
|
---|
763 |
|
---|
764 | if (digest == NULL || sig == NULL || key == NULL || answer == NULL) {
|
---|
765 | return BAD_FUNC_ARG;
|
---|
766 | }
|
---|
767 |
|
---|
768 | if (mp_init_multi(&w, &u1, &u2, &v, &r, &s) != MP_OKAY)
|
---|
769 | return MP_INIT_E;
|
---|
770 |
|
---|
771 | /* set r and s from signature */
|
---|
772 | if (mp_read_unsigned_bin(&r, sig, DSA_HALF_SIZE) != MP_OKAY ||
|
---|
773 | mp_read_unsigned_bin(&s, sig + DSA_HALF_SIZE, DSA_HALF_SIZE) != MP_OKAY)
|
---|
774 | ret = MP_READ_E;
|
---|
775 |
|
---|
776 | /* sanity checks */
|
---|
777 | if (ret == 0) {
|
---|
778 | if (mp_iszero(&r) == MP_YES || mp_iszero(&s) == MP_YES ||
|
---|
779 | mp_cmp(&r, &key->q) != MP_LT || mp_cmp(&s, &key->q) != MP_LT) {
|
---|
780 | ret = MP_ZERO_E;
|
---|
781 | }
|
---|
782 | }
|
---|
783 |
|
---|
784 | /* put H into u1 from sha digest */
|
---|
785 | if (ret == 0 && mp_read_unsigned_bin(&u1,digest,WC_SHA_DIGEST_SIZE) != MP_OKAY)
|
---|
786 | ret = MP_READ_E;
|
---|
787 |
|
---|
788 | /* w = s invmod q */
|
---|
789 | if (ret == 0 && mp_invmod(&s, &key->q, &w) != MP_OKAY)
|
---|
790 | ret = MP_INVMOD_E;
|
---|
791 |
|
---|
792 | /* u1 = (H * w) % q */
|
---|
793 | if (ret == 0 && mp_mulmod(&u1, &w, &key->q, &u1) != MP_OKAY)
|
---|
794 | ret = MP_MULMOD_E;
|
---|
795 |
|
---|
796 | /* u2 = (r * w) % q */
|
---|
797 | if (ret == 0 && mp_mulmod(&r, &w, &key->q, &u2) != MP_OKAY)
|
---|
798 | ret = MP_MULMOD_E;
|
---|
799 |
|
---|
800 | /* verify v = ((g^u1 * y^u2) mod p) mod q */
|
---|
801 | if (ret == 0 && mp_exptmod(&key->g, &u1, &key->p, &u1) != MP_OKAY)
|
---|
802 | ret = MP_EXPTMOD_E;
|
---|
803 |
|
---|
804 | if (ret == 0 && mp_exptmod(&key->y, &u2, &key->p, &u2) != MP_OKAY)
|
---|
805 | ret = MP_EXPTMOD_E;
|
---|
806 |
|
---|
807 | if (ret == 0 && mp_mulmod(&u1, &u2, &key->p, &v) != MP_OKAY)
|
---|
808 | ret = MP_MULMOD_E;
|
---|
809 |
|
---|
810 | if (ret == 0 && mp_mod(&v, &key->q, &v) != MP_OKAY)
|
---|
811 | ret = MP_MULMOD_E;
|
---|
812 |
|
---|
813 | /* do they match */
|
---|
814 | if (ret == 0 && mp_cmp(&r, &v) == MP_EQ)
|
---|
815 | *answer = 1;
|
---|
816 | else
|
---|
817 | *answer = 0;
|
---|
818 |
|
---|
819 | mp_clear(&s);
|
---|
820 | mp_clear(&r);
|
---|
821 | mp_clear(&u1);
|
---|
822 | mp_clear(&u2);
|
---|
823 | mp_clear(&w);
|
---|
824 | mp_clear(&v);
|
---|
825 |
|
---|
826 | return ret;
|
---|
827 | }
|
---|
828 |
|
---|
829 |
|
---|
830 | #endif /* NO_DSA */
|
---|
831 |
|
---|