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1 /* crypto/dh/dh_key.c */ |
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2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) |
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3 * All rights reserved. |
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4 * |
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5 * This package is an SSL implementation written |
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6 * by Eric Young (eay@cryptsoft.com). |
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7 * The implementation was written so as to conform with Netscapes SSL. |
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8 * |
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9 * This library is free for commercial and non-commercial use as long as |
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10 * the following conditions are aheared to. The following conditions |
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11 * apply to all code found in this distribution, be it the RC4, RSA, |
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12 * lhash, DES, etc., code; not just the SSL code. The SSL documentation |
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13 * included with this distribution is covered by the same copyright terms |
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14 * except that the holder is Tim Hudson (tjh@cryptsoft.com). |
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15 * |
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16 * Copyright remains Eric Young's, and as such any Copyright notices in |
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17 * the code are not to be removed. |
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18 * If this package is used in a product, Eric Young should be given attribution |
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19 * as the author of the parts of the library used. |
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20 * This can be in the form of a textual message at program startup or |
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21 * in documentation (online or textual) provided with the package. |
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22 * |
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23 * Redistribution and use in source and binary forms, with or without |
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24 * modification, are permitted provided that the following conditions |
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25 * are met: |
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26 * 1. Redistributions of source code must retain the copyright |
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27 * notice, this list of conditions and the following disclaimer. |
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28 * 2. Redistributions in binary form must reproduce the above copyright |
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29 * notice, this list of conditions and the following disclaimer in the |
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30 * documentation and/or other materials provided with the distribution. |
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31 * 3. All advertising materials mentioning features or use of this software |
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32 * must display the following acknowledgement: |
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33 * "This product includes cryptographic software written by |
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34 * Eric Young (eay@cryptsoft.com)" |
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35 * The word 'cryptographic' can be left out if the rouines from the library |
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36 * being used are not cryptographic related :-). |
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37 * 4. If you include any Windows specific code (or a derivative thereof) from |
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38 * the apps directory (application code) you must include an acknowledgement: |
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39 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" |
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40 * |
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41 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND |
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42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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44 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
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45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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51 * SUCH DAMAGE. |
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52 * |
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53 * The licence and distribution terms for any publically available version or |
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54 * derivative of this code cannot be changed. i.e. this code cannot simply be |
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55 * copied and put under another distribution licence |
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56 * [including the GNU Public Licence.] |
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57 */ |
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58 |
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59 /* |
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60 © Portions copyright (c) 2006 Nokia Corporation. All rights reserved. |
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61 */ |
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62 |
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63 |
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64 #include <stdio.h> |
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65 #include "cryptlib.h" |
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66 #include <openssl/bn.h> |
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67 #include <openssl/rand.h> |
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68 #include <openssl/dh.h> |
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69 #if (defined(SYMBIAN) && (defined(__WINSCW__) || defined(__WINS__))) |
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70 #include "libcrypto_wsd_macros.h" |
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71 #include "libcrypto_wsd.h" |
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72 #endif |
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73 |
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74 |
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75 static int generate_key(DH *dh); |
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76 static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh); |
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77 static int dh_bn_mod_exp(const DH *dh, BIGNUM *r, |
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78 const BIGNUM *a, const BIGNUM *p, |
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79 const BIGNUM *m, BN_CTX *ctx, |
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80 BN_MONT_CTX *m_ctx); |
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81 static int dh_init(DH *dh); |
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82 static int dh_finish(DH *dh); |
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83 |
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84 EXPORT_C int DH_generate_key(DH *dh) |
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85 { |
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86 return dh->meth->generate_key(dh); |
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87 } |
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88 |
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89 EXPORT_C int DH_compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh) |
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90 { |
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91 return dh->meth->compute_key(key, pub_key, dh); |
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92 } |
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93 |
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94 #ifndef EMULATOR |
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95 static DH_METHOD dh_ossl = { |
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96 "OpenSSL DH Method", |
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97 generate_key, |
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98 compute_key, |
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99 dh_bn_mod_exp, |
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100 dh_init, |
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101 dh_finish, |
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102 0, |
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103 NULL, |
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104 NULL |
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105 }; |
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106 #else |
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107 GET_STATIC_VAR_FROM_TLS(dh_ossl,dh_key,DH_METHOD) |
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108 #define dh_ossl (*GET_WSD_VAR_NAME(dh_ossl,dh_key, s)()) |
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109 const DH_METHOD temp_s_dh_ossl = { |
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110 "OpenSSL DH Method", |
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111 generate_key, |
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112 compute_key, |
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113 dh_bn_mod_exp, |
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114 dh_init, |
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115 dh_finish, |
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116 0, |
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117 NULL, |
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118 NULL |
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119 }; |
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120 |
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121 #endif |
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122 EXPORT_C const DH_METHOD *DH_OpenSSL(void) |
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123 { |
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124 return &dh_ossl; |
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125 } |
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126 |
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127 static int generate_key(DH *dh) |
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128 { |
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129 int ok=0; |
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130 int generate_new_key=0; |
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131 unsigned l; |
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132 BN_CTX *ctx; |
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133 BN_MONT_CTX *mont=NULL; |
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134 BIGNUM *pub_key=NULL,*priv_key=NULL; |
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135 |
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136 ctx = BN_CTX_new(); |
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137 if (ctx == NULL) goto err; |
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138 |
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139 if (dh->priv_key == NULL) |
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140 { |
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141 priv_key=BN_new(); |
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142 if (priv_key == NULL) goto err; |
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143 generate_new_key=1; |
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144 } |
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145 else |
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146 priv_key=dh->priv_key; |
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147 |
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148 if (dh->pub_key == NULL) |
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149 { |
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150 pub_key=BN_new(); |
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151 if (pub_key == NULL) goto err; |
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152 } |
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153 else |
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154 pub_key=dh->pub_key; |
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155 |
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156 |
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157 if (dh->flags & DH_FLAG_CACHE_MONT_P) |
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158 { |
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159 mont = BN_MONT_CTX_set_locked(&dh->method_mont_p, |
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160 CRYPTO_LOCK_DH, dh->p, ctx); |
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161 if (!mont) |
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162 goto err; |
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163 } |
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164 |
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165 if (generate_new_key) |
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166 { |
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167 l = dh->length ? dh->length : BN_num_bits(dh->p)-1; /* secret exponent length */ |
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168 if (!BN_rand(priv_key, l, 0, 0)) goto err; |
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169 } |
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170 |
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171 { |
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172 BIGNUM local_prk; |
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173 BIGNUM *prk; |
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174 |
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175 if ((dh->flags & DH_FLAG_NO_EXP_CONSTTIME) == 0) |
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176 { |
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177 BN_init(&local_prk); |
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178 prk = &local_prk; |
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179 BN_with_flags(prk, priv_key, BN_FLG_CONSTTIME); |
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180 } |
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181 else |
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182 prk = priv_key; |
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183 |
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184 if (!dh->meth->bn_mod_exp(dh, pub_key, dh->g, prk, dh->p, ctx, mont)) goto err; |
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185 } |
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186 |
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187 dh->pub_key=pub_key; |
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188 dh->priv_key=priv_key; |
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189 ok=1; |
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190 err: |
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191 if (ok != 1) |
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192 DHerr(DH_F_GENERATE_KEY,ERR_R_BN_LIB); |
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193 |
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194 if ((pub_key != NULL) && (dh->pub_key == NULL)) BN_free(pub_key); |
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195 if ((priv_key != NULL) && (dh->priv_key == NULL)) BN_free(priv_key); |
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196 BN_CTX_free(ctx); |
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197 return(ok); |
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198 } |
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199 |
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200 static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh) |
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201 { |
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202 BN_CTX *ctx=NULL; |
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203 BN_MONT_CTX *mont=NULL; |
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204 BIGNUM *tmp; |
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205 int ret= -1; |
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206 int check_result; |
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207 if (BN_num_bits(dh->p) > OPENSSL_DH_MAX_MODULUS_BITS) |
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208 { |
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209 DHerr(DH_F_COMPUTE_KEY,DH_R_MODULUS_TOO_LARGE); |
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210 goto err; |
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211 } |
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212 ctx = BN_CTX_new(); |
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213 if (ctx == NULL) goto err; |
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214 BN_CTX_start(ctx); |
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215 tmp = BN_CTX_get(ctx); |
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216 |
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217 if (dh->priv_key == NULL) |
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218 { |
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219 DHerr(DH_F_COMPUTE_KEY,DH_R_NO_PRIVATE_VALUE); |
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220 goto err; |
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221 } |
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222 |
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223 if (dh->flags & DH_FLAG_CACHE_MONT_P) |
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224 { |
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225 mont = BN_MONT_CTX_set_locked(&dh->method_mont_p, |
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226 CRYPTO_LOCK_DH, dh->p, ctx); |
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227 if ((dh->flags & DH_FLAG_NO_EXP_CONSTTIME) == 0) |
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228 { |
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229 /* XXX */ |
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230 BN_set_flags(dh->priv_key, BN_FLG_CONSTTIME); |
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231 } |
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232 if (!mont) |
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233 goto err; |
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234 } |
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235 |
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236 if (!DH_check_pub_key(dh, pub_key, &check_result) || check_result) |
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237 { |
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238 DHerr(DH_F_COMPUTE_KEY,DH_R_INVALID_PUBKEY); |
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239 goto err; |
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240 } |
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241 |
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242 if (!dh->meth->bn_mod_exp(dh, tmp, pub_key, dh->priv_key,dh->p,ctx,mont)) |
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243 { |
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244 DHerr(DH_F_COMPUTE_KEY,ERR_R_BN_LIB); |
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245 goto err; |
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246 } |
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247 |
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248 ret=BN_bn2bin(tmp,key); |
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249 err: |
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250 if (ctx != NULL) |
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251 { |
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252 BN_CTX_end(ctx); |
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253 BN_CTX_free(ctx); |
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254 } |
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255 return(ret); |
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256 } |
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257 |
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258 static int dh_bn_mod_exp(const DH *dh, BIGNUM *r, |
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259 const BIGNUM *a, const BIGNUM *p, |
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260 const BIGNUM *m, BN_CTX *ctx, |
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261 BN_MONT_CTX *m_ctx) |
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262 { |
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263 /* If a is only one word long and constant time is false, use the faster |
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264 * exponenentiation function. |
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265 */ |
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266 if (a->top == 1 && ((dh->flags & DH_FLAG_NO_EXP_CONSTTIME) != 0)) |
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267 { |
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268 BN_ULONG A = a->d[0]; |
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269 return BN_mod_exp_mont_word(r,A,p,m,ctx,m_ctx); |
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270 } |
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271 else |
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272 return BN_mod_exp_mont(r,a,p,m,ctx,m_ctx); |
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273 } |
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274 |
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275 |
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276 static int dh_init(DH *dh) |
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277 { |
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278 dh->flags |= DH_FLAG_CACHE_MONT_P; |
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279 return(1); |
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280 } |
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281 |
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282 static int dh_finish(DH *dh) |
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283 { |
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284 if(dh->method_mont_p) |
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285 BN_MONT_CTX_free(dh->method_mont_p); |
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286 return(1); |
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287 } |