1 | // =================================================================== |
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2 | // |
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3 | // Copyright (c) 2005, Intel Corp. |
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4 | // All rights reserved. |
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5 | // |
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6 | // Redistribution and use in source and binary forms, with or without |
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7 | // modification, are permitted provided that the following conditions |
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8 | // are met: |
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9 | // |
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10 | // * Redistributions of source code must retain the above copyright |
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11 | // notice, this list of conditions and the following disclaimer. |
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12 | // * Redistributions in binary form must reproduce the above |
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13 | // copyright notice, this list of conditions and the following |
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14 | // disclaimer in the documentation and/or other materials provided |
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15 | // with the distribution. |
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16 | // * Neither the name of Intel Corporation nor the names of its |
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17 | // contributors may be used to endorse or promote products derived |
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18 | // from this software without specific prior written permission. |
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19 | // |
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20 | // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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21 | // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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22 | // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
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23 | // FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
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24 | // COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
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25 | // INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
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26 | // (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR |
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27 | // SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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28 | // HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, |
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29 | // STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
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30 | // ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED |
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31 | // OF THE POSSIBILITY OF SUCH DAMAGE. |
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32 | // =================================================================== |
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33 | // |
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34 | // sym_crypto.c |
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35 | // |
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36 | // Symmetric crypto portion of crypto |
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37 | // |
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38 | // ================================================================== |
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39 | |
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40 | #include <openssl/evp.h> |
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41 | #include <openssl/rand.h> |
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42 | |
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43 | #include "tcg.h" |
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44 | #include "sym_crypto.h" |
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45 | |
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46 | typedef enum crypt_op_type_t { |
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47 | CRYPT_ENCRYPT, |
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48 | CRYPT_DECRYPT |
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49 | } crypt_op_type_t; |
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50 | |
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51 | TPM_RESULT ossl_symcrypto_op (symkey_t* key, |
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52 | const buffer_t* in, |
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53 | const buffer_t* iv, |
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54 | buffer_t * out, |
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55 | crypt_op_type_t optype); |
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56 | |
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57 | |
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58 | // this is initialized in Crypto_Init() |
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59 | const EVP_CIPHER * SYM_CIPHER = NULL; |
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60 | |
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61 | const BYTE ZERO_IV[EVP_MAX_IV_LENGTH] = {0}; |
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62 | |
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63 | |
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64 | TPM_RESULT Crypto_symcrypto_initkey (symkey_t * key, const buffer_t* keybits) { |
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65 | TPM_RESULT status = TPM_SUCCESS; |
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66 | |
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67 | EVP_CIPHER_CTX_init (&key->context); |
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68 | |
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69 | key->cipher = SYM_CIPHER; |
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70 | |
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71 | TPMTRYRETURN( buffer_init_copy (&key->key, keybits)); |
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72 | |
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73 | goto egress; |
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74 | |
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75 | abort_egress: |
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76 | EVP_CIPHER_CTX_cleanup (&key->context); |
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77 | |
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78 | egress: |
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79 | |
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80 | return status; |
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81 | } |
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82 | |
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83 | |
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84 | |
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85 | TPM_RESULT Crypto_symcrypto_genkey (symkey_t * key) { |
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86 | int res; |
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87 | TPM_RESULT status = TPM_SUCCESS; |
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88 | |
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89 | // hmm, EVP_CIPHER_CTX_init does not return a value |
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90 | EVP_CIPHER_CTX_init (&key->context); |
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91 | |
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92 | key->cipher = SYM_CIPHER; |
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93 | |
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94 | TPMTRYRETURN( buffer_init (&key->key, EVP_CIPHER_key_length(key->cipher), NULL)) ; |
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95 | |
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96 | // and generate the key material |
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97 | res = RAND_pseudo_bytes (key->key.bytes, key->key.size); |
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98 | if (res < 0) |
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99 | ERRORDIE (TPM_SHORTRANDOM); |
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100 | |
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101 | |
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102 | goto egress; |
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103 | |
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104 | abort_egress: |
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105 | EVP_CIPHER_CTX_cleanup (&key->context); |
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106 | buffer_free (&key->key); |
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107 | |
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108 | egress: |
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109 | return status; |
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110 | } |
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111 | |
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112 | |
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113 | TPM_RESULT Crypto_symcrypto_encrypt (symkey_t* key, |
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114 | const buffer_t* clear, |
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115 | buffer_t* o_cipher) { |
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116 | TPM_RESULT status = TPM_SUCCESS; |
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117 | |
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118 | buffer_t iv, cipher_alias; |
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119 | |
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120 | buffer_init_const (&iv, EVP_MAX_IV_LENGTH, ZERO_IV); |
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121 | |
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122 | buffer_init (o_cipher, |
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123 | clear->size + |
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124 | EVP_CIPHER_iv_length(key->cipher) + |
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125 | EVP_CIPHER_block_size (key->cipher), |
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126 | 0); |
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127 | |
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128 | // copy the IV into the front |
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129 | buffer_copy (o_cipher, &iv); |
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130 | |
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131 | // make an alias into which we'll put the ciphertext |
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132 | buffer_init_alias (&cipher_alias, o_cipher, EVP_CIPHER_iv_length(key->cipher), 0); |
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133 | |
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134 | TPMTRYRETURN( ossl_symcrypto_op (key, clear, &iv, &cipher_alias, CRYPT_ENCRYPT) ); |
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135 | |
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136 | // set the output size correctly |
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137 | o_cipher->size += cipher_alias.size; |
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138 | |
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139 | goto egress; |
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140 | |
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141 | abort_egress: |
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142 | |
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143 | egress: |
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144 | |
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145 | return status; |
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146 | |
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147 | } |
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148 | |
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149 | |
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150 | |
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151 | TPM_RESULT Crypto_symcrypto_decrypt (symkey_t* key, |
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152 | const buffer_t* cipher, |
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153 | buffer_t* o_clear) { |
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154 | TPM_RESULT status = TPM_SUCCESS; |
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155 | |
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156 | buffer_t iv, cipher_alias; |
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157 | |
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158 | // alias for the IV |
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159 | buffer_init_alias (&iv, cipher, 0, EVP_CIPHER_iv_length(key->cipher)); |
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160 | |
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161 | // make an alias to where the ciphertext is, after the IV |
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162 | buffer_init_alias (&cipher_alias, cipher, EVP_CIPHER_iv_length(key->cipher), 0); |
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163 | |
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164 | // prepare the output buffer |
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165 | TPMTRYRETURN( buffer_init (o_clear, |
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166 | cipher->size |
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167 | - EVP_CIPHER_iv_length(key->cipher) |
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168 | + EVP_CIPHER_block_size(key->cipher), |
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169 | 0) ); |
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170 | |
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171 | // and decrypt |
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172 | TPMTRYRETURN ( ossl_symcrypto_op (key, &cipher_alias, &iv, o_clear, CRYPT_DECRYPT) ); |
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173 | |
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174 | goto egress; |
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175 | |
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176 | abort_egress: |
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177 | buffer_free (o_clear); |
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178 | |
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179 | egress: |
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180 | |
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181 | return status; |
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182 | } |
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183 | |
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184 | |
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185 | |
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186 | TPM_RESULT Crypto_symcrypto_freekey (symkey_t * key) { |
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187 | buffer_memset (&key->key, 0); |
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188 | buffer_free (&key->key); |
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189 | |
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190 | EVP_CIPHER_CTX_cleanup (&key->context); |
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191 | |
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192 | return TPM_SUCCESS; |
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193 | } |
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194 | |
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195 | |
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196 | TPM_RESULT ossl_symcrypto_op (symkey_t* key, |
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197 | const buffer_t* in, |
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198 | const buffer_t* iv, |
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199 | buffer_t * out, |
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200 | crypt_op_type_t optype) { |
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201 | TPM_RESULT status = TPM_SUCCESS; |
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202 | |
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203 | int inlen, outlen; |
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204 | tpm_size_t running; |
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205 | |
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206 | if ( ! EVP_CipherInit_ex (&key->context, |
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207 | key->cipher, NULL, key->key.bytes, iv->bytes, |
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208 | optype == CRYPT_ENCRYPT ? 1 : 0) ) |
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209 | ERRORDIE (TPM_FAIL); |
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210 | |
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211 | |
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212 | |
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213 | inlen = in->size; |
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214 | |
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215 | outlen = 0; |
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216 | running = 0; |
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217 | |
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218 | |
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219 | if ( ! EVP_CipherUpdate (&key->context, out->bytes, &outlen, in->bytes, inlen) ) |
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220 | ERRORDIE (TPM_FAIL); |
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221 | |
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222 | running += outlen; |
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223 | |
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224 | if ( ! EVP_CipherFinal_ex (&key->context, out->bytes + running, &outlen) ) |
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225 | ERRORDIE (TPM_FAIL); |
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226 | |
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227 | running += outlen; |
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228 | |
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229 | out->size = running; |
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230 | |
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231 | goto egress; |
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232 | |
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233 | abort_egress: |
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234 | egress: |
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235 | |
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236 | return status; |
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237 | } |
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