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1 /* crypto/dsa/dsa_ossl.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 /* Original version from Steven Schoch <schoch@sheba.arc.nasa.gov> */ |
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60 /* |
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61 © Portions copyright (c) 2006 Nokia Corporation. All rights reserved. |
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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/dsa.h> |
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68 #include <openssl/rand.h> |
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69 #include <openssl/asn1.h> |
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70 #if (defined(SYMBIAN) && (defined(__WINSCW__) || defined(__WINS__))) |
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71 #include "libcrypto_wsd_macros.h" |
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72 #include "libcrypto_wsd.h" |
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73 #endif |
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74 |
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75 static DSA_SIG *dsa_do_sign(const unsigned char *dgst, int dlen, DSA *dsa); |
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76 static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in, BIGNUM **kinvp, BIGNUM **rp); |
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77 static int dsa_do_verify(const unsigned char *dgst, int dgst_len, DSA_SIG *sig, |
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78 DSA *dsa); |
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79 static int dsa_init(DSA *dsa); |
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80 static int dsa_finish(DSA *dsa); |
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81 |
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82 #ifndef EMULATOR |
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83 static DSA_METHOD openssl_dsa_meth = { |
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84 "OpenSSL DSA method", |
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85 dsa_do_sign, |
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86 dsa_sign_setup, |
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87 dsa_do_verify, |
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88 NULL, /* dsa_mod_exp, */ |
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89 NULL, /* dsa_bn_mod_exp, */ |
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90 dsa_init, |
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91 dsa_finish, |
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92 0, |
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93 NULL, |
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94 NULL, |
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95 NULL |
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96 }; |
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97 #else |
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98 GET_STATIC_VAR_FROM_TLS(openssl_dsa_meth,dsa_ossl,DSA_METHOD) |
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99 #define openssl_dsa_meth (*GET_WSD_VAR_NAME(openssl_dsa_meth,dsa_ossl, s)()) |
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100 const DSA_METHOD temp_s_openssl_dsa_meth = { |
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101 "OpenSSL DSA method", |
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102 dsa_do_sign, |
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103 dsa_sign_setup, |
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104 dsa_do_verify, |
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105 NULL, /* dsa_mod_exp, */ |
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106 NULL, /* dsa_bn_mod_exp, */ |
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107 dsa_init, |
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108 dsa_finish, |
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109 0, |
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110 NULL, |
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111 NULL, |
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112 NULL |
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113 }; |
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114 #endif |
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115 |
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116 /* These macro wrappers replace attempts to use the dsa_mod_exp() and |
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117 * bn_mod_exp() handlers in the DSA_METHOD structure. We avoid the problem of |
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118 * having a the macro work as an expression by bundling an "err_instr". So; |
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119 * |
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120 * if (!dsa->meth->bn_mod_exp(dsa, r,dsa->g,&k,dsa->p,ctx, |
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121 * dsa->method_mont_p)) goto err; |
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122 * |
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123 * can be replaced by; |
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124 * |
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125 * DSA_BN_MOD_EXP(goto err, dsa, r, dsa->g, &k, dsa->p, ctx, |
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126 * dsa->method_mont_p); |
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127 */ |
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128 |
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129 #define DSA_MOD_EXP(err_instr,dsa,rr,a1,p1,a2,p2,m,ctx,in_mont) \ |
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130 do { \ |
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131 int _tmp_res53; \ |
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132 if((dsa)->meth->dsa_mod_exp) \ |
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133 _tmp_res53 = (dsa)->meth->dsa_mod_exp((dsa), (rr), (a1), (p1), \ |
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134 (a2), (p2), (m), (ctx), (in_mont)); \ |
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135 else \ |
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136 _tmp_res53 = BN_mod_exp2_mont((rr), (a1), (p1), (a2), (p2), \ |
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137 (m), (ctx), (in_mont)); \ |
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138 if(!_tmp_res53) err_instr; \ |
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139 } while(0) |
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140 #define DSA_BN_MOD_EXP(err_instr,dsa,r,a,p,m,ctx,m_ctx) \ |
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141 do { \ |
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142 int _tmp_res53; \ |
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143 if((dsa)->meth->bn_mod_exp) \ |
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144 _tmp_res53 = (dsa)->meth->bn_mod_exp((dsa), (r), (a), (p), \ |
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145 (m), (ctx), (m_ctx)); \ |
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146 else \ |
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147 _tmp_res53 = BN_mod_exp_mont((r), (a), (p), (m), (ctx), (m_ctx)); \ |
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148 if(!_tmp_res53) err_instr; \ |
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149 } while(0) |
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150 |
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151 EXPORT_C const DSA_METHOD *DSA_OpenSSL(void) |
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152 { |
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153 return &openssl_dsa_meth; |
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154 } |
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155 |
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156 static DSA_SIG *dsa_do_sign(const unsigned char *dgst, int dlen, DSA *dsa) |
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157 { |
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158 BIGNUM *kinv=NULL,*r=NULL,*s=NULL; |
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159 BIGNUM m; |
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160 BIGNUM xr; |
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161 BN_CTX *ctx=NULL; |
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162 int i,reason=ERR_R_BN_LIB; |
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163 DSA_SIG *ret=NULL; |
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164 |
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165 BN_init(&m); |
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166 BN_init(&xr); |
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167 |
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168 if (!dsa->p || !dsa->q || !dsa->g) |
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169 { |
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170 reason=DSA_R_MISSING_PARAMETERS; |
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171 goto err; |
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172 } |
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173 |
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174 s=BN_new(); |
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175 if (s == NULL) goto err; |
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176 |
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177 i=BN_num_bytes(dsa->q); /* should be 20 */ |
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178 if ((dlen > i) || (dlen > 50)) |
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179 { |
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180 reason=DSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE; |
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181 goto err; |
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182 } |
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183 |
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184 ctx=BN_CTX_new(); |
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185 if (ctx == NULL) goto err; |
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186 |
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187 if ((dsa->kinv == NULL) || (dsa->r == NULL)) |
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188 { |
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189 if (!DSA_sign_setup(dsa,ctx,&kinv,&r)) goto err; |
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190 } |
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191 else |
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192 { |
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193 kinv=dsa->kinv; |
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194 dsa->kinv=NULL; |
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195 r=dsa->r; |
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196 dsa->r=NULL; |
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197 } |
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198 |
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199 if (BN_bin2bn(dgst,dlen,&m) == NULL) goto err; |
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200 |
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201 /* Compute s = inv(k) (m + xr) mod q */ |
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202 if (!BN_mod_mul(&xr,dsa->priv_key,r,dsa->q,ctx)) goto err;/* s = xr */ |
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203 if (!BN_add(s, &xr, &m)) goto err; /* s = m + xr */ |
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204 if (BN_cmp(s,dsa->q) > 0) |
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205 BN_sub(s,s,dsa->q); |
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206 if (!BN_mod_mul(s,s,kinv,dsa->q,ctx)) goto err; |
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207 |
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208 ret=DSA_SIG_new(); |
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209 if (ret == NULL) goto err; |
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210 ret->r = r; |
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211 ret->s = s; |
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212 |
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213 err: |
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214 if (!ret) |
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215 { |
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216 DSAerr(DSA_F_DSA_DO_SIGN,reason); |
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217 BN_free(r); |
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218 BN_free(s); |
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219 } |
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220 if (ctx != NULL) BN_CTX_free(ctx); |
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221 BN_clear_free(&m); |
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222 BN_clear_free(&xr); |
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223 if (kinv != NULL) /* dsa->kinv is NULL now if we used it */ |
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224 BN_clear_free(kinv); |
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225 return(ret); |
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226 } |
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227 |
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228 static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in, BIGNUM **kinvp, BIGNUM **rp) |
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229 { |
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230 BN_CTX *ctx; |
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231 BIGNUM k,kq,*K,*kinv=NULL,*r=NULL; |
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232 int ret=0; |
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233 |
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234 if (!dsa->p || !dsa->q || !dsa->g) |
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235 { |
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236 DSAerr(DSA_F_DSA_SIGN_SETUP,DSA_R_MISSING_PARAMETERS); |
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237 return 0; |
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238 } |
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239 |
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240 BN_init(&k); |
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241 BN_init(&kq); |
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242 |
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243 if (ctx_in == NULL) |
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244 { |
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245 if ((ctx=BN_CTX_new()) == NULL) goto err; |
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246 } |
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247 else |
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248 ctx=ctx_in; |
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249 |
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250 if ((r=BN_new()) == NULL) goto err; |
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251 |
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252 /* Get random k */ |
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253 do |
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254 if (!BN_rand_range(&k, dsa->q)) goto err; |
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255 while (BN_is_zero(&k)); |
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256 if ((dsa->flags & DSA_FLAG_NO_EXP_CONSTTIME) == 0) |
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257 { |
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258 BN_set_flags(&k, BN_FLG_CONSTTIME); |
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259 } |
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260 |
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261 if (dsa->flags & DSA_FLAG_CACHE_MONT_P) |
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262 { |
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263 if (!BN_MONT_CTX_set_locked(&dsa->method_mont_p, |
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264 CRYPTO_LOCK_DSA, |
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265 dsa->p, ctx)) |
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266 goto err; |
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267 } |
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268 |
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269 /* Compute r = (g^k mod p) mod q */ |
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270 |
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271 if ((dsa->flags & DSA_FLAG_NO_EXP_CONSTTIME) == 0) |
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272 { |
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273 if (!BN_copy(&kq, &k)) goto err; |
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274 |
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275 /* We do not want timing information to leak the length of k, |
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276 * so we compute g^k using an equivalent exponent of fixed length. |
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277 * |
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278 * (This is a kludge that we need because the BN_mod_exp_mont() |
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279 * does not let us specify the desired timing behaviour.) */ |
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280 |
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281 if (!BN_add(&kq, &kq, dsa->q)) goto err; |
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282 if (BN_num_bits(&kq) <= BN_num_bits(dsa->q)) |
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283 { |
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284 if (!BN_add(&kq, &kq, dsa->q)) goto err; |
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285 } |
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286 |
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287 K = &kq; |
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288 } |
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289 else |
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290 { |
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291 K = &k; |
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292 } |
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293 DSA_BN_MOD_EXP(goto err, dsa, r, dsa->g, K, dsa->p, ctx, |
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294 dsa->method_mont_p); |
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295 if (!BN_mod(r,r,dsa->q,ctx)) goto err; |
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296 |
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297 /* Compute part of 's = inv(k) (m + xr) mod q' */ |
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298 if ((kinv=BN_mod_inverse(NULL,&k,dsa->q,ctx)) == NULL) goto err; |
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299 |
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300 if (*kinvp != NULL) BN_clear_free(*kinvp); |
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301 *kinvp=kinv; |
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302 kinv=NULL; |
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303 if (*rp != NULL) BN_clear_free(*rp); |
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304 *rp=r; |
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305 ret=1; |
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306 err: |
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307 if (!ret) |
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308 { |
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309 DSAerr(DSA_F_DSA_SIGN_SETUP,ERR_R_BN_LIB); |
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310 if (kinv != NULL) BN_clear_free(kinv); |
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311 if (r != NULL) BN_clear_free(r); |
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312 } |
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313 if (ctx_in == NULL) BN_CTX_free(ctx); |
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314 if (kinv != NULL) BN_clear_free(kinv); |
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315 BN_clear_free(&k); |
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316 BN_clear_free(&kq); |
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317 return(ret); |
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318 } |
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319 |
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320 static int dsa_do_verify(const unsigned char *dgst, int dgst_len, DSA_SIG *sig, |
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321 DSA *dsa) |
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322 { |
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323 BN_CTX *ctx; |
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324 BIGNUM u1,u2,t1; |
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325 BN_MONT_CTX *mont=NULL; |
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326 int ret = -1; |
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327 if (!dsa->p || !dsa->q || !dsa->g) |
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328 { |
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329 DSAerr(DSA_F_DSA_DO_VERIFY,DSA_R_MISSING_PARAMETERS); |
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330 return -1; |
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331 } |
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332 |
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333 if (BN_num_bits(dsa->q) != 160) |
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334 { |
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335 DSAerr(DSA_F_DSA_DO_VERIFY,DSA_R_BAD_Q_VALUE); |
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336 return -1; |
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337 } |
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338 |
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339 if (BN_num_bits(dsa->p) > OPENSSL_DSA_MAX_MODULUS_BITS) |
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340 { |
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341 DSAerr(DSA_F_DSA_DO_VERIFY,DSA_R_MODULUS_TOO_LARGE); |
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342 return -1; |
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343 } |
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344 |
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345 BN_init(&u1); |
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346 BN_init(&u2); |
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347 BN_init(&t1); |
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348 |
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349 if ((ctx=BN_CTX_new()) == NULL) goto err; |
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350 |
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351 if (BN_is_zero(sig->r) || BN_is_negative(sig->r) || |
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352 BN_ucmp(sig->r, dsa->q) >= 0) |
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353 { |
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354 ret = 0; |
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355 goto err; |
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356 } |
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357 if (BN_is_zero(sig->s) || BN_is_negative(sig->s) || |
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358 BN_ucmp(sig->s, dsa->q) >= 0) |
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359 { |
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360 ret = 0; |
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361 goto err; |
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362 } |
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363 |
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364 /* Calculate W = inv(S) mod Q |
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365 * save W in u2 */ |
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366 if ((BN_mod_inverse(&u2,sig->s,dsa->q,ctx)) == NULL) goto err; |
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367 |
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368 /* save M in u1 */ |
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369 if (BN_bin2bn(dgst,dgst_len,&u1) == NULL) goto err; |
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370 |
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371 /* u1 = M * w mod q */ |
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372 if (!BN_mod_mul(&u1,&u1,&u2,dsa->q,ctx)) goto err; |
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373 |
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374 /* u2 = r * w mod q */ |
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375 if (!BN_mod_mul(&u2,sig->r,&u2,dsa->q,ctx)) goto err; |
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376 |
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377 |
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378 if (dsa->flags & DSA_FLAG_CACHE_MONT_P) |
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379 { |
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380 mont = BN_MONT_CTX_set_locked(&dsa->method_mont_p, |
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381 CRYPTO_LOCK_DSA, dsa->p, ctx); |
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382 if (!mont) |
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383 goto err; |
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384 } |
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385 |
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386 |
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387 DSA_MOD_EXP(goto err, dsa, &t1, dsa->g, &u1, dsa->pub_key, &u2, dsa->p, ctx, mont); |
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388 /* BN_copy(&u1,&t1); */ |
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389 /* let u1 = u1 mod q */ |
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390 if (!BN_mod(&u1,&t1,dsa->q,ctx)) goto err; |
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391 |
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392 /* V is now in u1. If the signature is correct, it will be |
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393 * equal to R. */ |
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394 ret=(BN_ucmp(&u1, sig->r) == 0); |
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395 |
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396 err: |
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397 /* XXX: surely this is wrong - if ret is 0, it just didn't verify; |
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398 there is no error in BN. Test should be ret == -1 (Ben) */ |
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399 if (ret != 1) DSAerr(DSA_F_DSA_DO_VERIFY,ERR_R_BN_LIB); |
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400 if (ctx != NULL) BN_CTX_free(ctx); |
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401 BN_free(&u1); |
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402 BN_free(&u2); |
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403 BN_free(&t1); |
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404 return(ret); |
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405 } |
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406 |
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407 static int dsa_init(DSA *dsa) |
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408 { |
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409 dsa->flags|=DSA_FLAG_CACHE_MONT_P; |
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410 return(1); |
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411 } |
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412 |
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413 static int dsa_finish(DSA *dsa) |
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414 { |
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415 if(dsa->method_mont_p) |
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416 BN_MONT_CTX_free(dsa->method_mont_p); |
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417 return(1); |
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418 } |
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419 |