1 | /*
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2 | * Generic ASN.1 parsing
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3 | *
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4 | * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
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5 | * SPDX-License-Identifier: Apache-2.0
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6 | *
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7 | * Licensed under the Apache License, Version 2.0 (the "License"); you may
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8 | * not use this file except in compliance with the License.
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9 | * You may obtain a copy of the License at
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10 | *
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11 | * http://www.apache.org/licenses/LICENSE-2.0
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12 | *
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13 | * Unless required by applicable law or agreed to in writing, software
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14 | * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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15 | * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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16 | * See the License for the specific language governing permissions and
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17 | * limitations under the License.
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18 | *
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19 | * This file is part of mbed TLS (https://tls.mbed.org)
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20 | */
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21 |
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22 | #if !defined(MBEDTLS_CONFIG_FILE)
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23 | #include "mbedtls/config.h"
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24 | #else
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25 | #include MBEDTLS_CONFIG_FILE
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26 | #endif
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27 |
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28 | #if defined(MBEDTLS_ASN1_PARSE_C)
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29 |
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30 | #include "mbedtls/asn1.h"
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31 | #include "mbedtls/platform_util.h"
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32 |
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33 | #include <string.h>
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34 |
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35 | #if defined(MBEDTLS_BIGNUM_C)
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36 | #include "mbedtls/bignum.h"
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37 | #endif
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38 |
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39 | #if defined(MBEDTLS_PLATFORM_C)
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40 | #include "mbedtls/platform.h"
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41 | #else
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42 | #include <stdlib.h>
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43 | #define mbedtls_calloc calloc
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44 | #define mbedtls_free free
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45 | #endif
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46 |
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47 | /*
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48 | * ASN.1 DER decoding routines
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49 | */
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50 | int mbedtls_asn1_get_len( unsigned char **p,
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51 | const unsigned char *end,
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52 | size_t *len )
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53 | {
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54 | if( ( end - *p ) < 1 )
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55 | return( MBEDTLS_ERR_ASN1_OUT_OF_DATA );
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56 |
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57 | if( ( **p & 0x80 ) == 0 )
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58 | *len = *(*p)++;
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59 | else
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60 | {
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61 | switch( **p & 0x7F )
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62 | {
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63 | case 1:
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64 | if( ( end - *p ) < 2 )
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65 | return( MBEDTLS_ERR_ASN1_OUT_OF_DATA );
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66 |
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67 | *len = (*p)[1];
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68 | (*p) += 2;
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69 | break;
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70 |
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71 | case 2:
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72 | if( ( end - *p ) < 3 )
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73 | return( MBEDTLS_ERR_ASN1_OUT_OF_DATA );
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74 |
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75 | *len = ( (size_t)(*p)[1] << 8 ) | (*p)[2];
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76 | (*p) += 3;
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77 | break;
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78 |
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79 | case 3:
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80 | if( ( end - *p ) < 4 )
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81 | return( MBEDTLS_ERR_ASN1_OUT_OF_DATA );
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82 |
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83 | *len = ( (size_t)(*p)[1] << 16 ) |
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84 | ( (size_t)(*p)[2] << 8 ) | (*p)[3];
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85 | (*p) += 4;
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86 | break;
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87 |
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88 | case 4:
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89 | if( ( end - *p ) < 5 )
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90 | return( MBEDTLS_ERR_ASN1_OUT_OF_DATA );
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91 |
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92 | *len = ( (size_t)(*p)[1] << 24 ) | ( (size_t)(*p)[2] << 16 ) |
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93 | ( (size_t)(*p)[3] << 8 ) | (*p)[4];
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94 | (*p) += 5;
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95 | break;
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96 |
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97 | default:
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98 | return( MBEDTLS_ERR_ASN1_INVALID_LENGTH );
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99 | }
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100 | }
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101 |
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102 | if( *len > (size_t) ( end - *p ) )
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103 | return( MBEDTLS_ERR_ASN1_OUT_OF_DATA );
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104 |
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105 | return( 0 );
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106 | }
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107 |
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108 | int mbedtls_asn1_get_tag( unsigned char **p,
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109 | const unsigned char *end,
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110 | size_t *len, int tag )
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111 | {
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112 | if( ( end - *p ) < 1 )
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113 | return( MBEDTLS_ERR_ASN1_OUT_OF_DATA );
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114 |
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115 | if( **p != tag )
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116 | return( MBEDTLS_ERR_ASN1_UNEXPECTED_TAG );
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117 |
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118 | (*p)++;
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119 |
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120 | return( mbedtls_asn1_get_len( p, end, len ) );
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121 | }
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122 |
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123 | int mbedtls_asn1_get_bool( unsigned char **p,
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124 | const unsigned char *end,
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125 | int *val )
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126 | {
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127 | int ret;
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128 | size_t len;
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129 |
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130 | if( ( ret = mbedtls_asn1_get_tag( p, end, &len, MBEDTLS_ASN1_BOOLEAN ) ) != 0 )
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131 | return( ret );
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132 |
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133 | if( len != 1 )
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134 | return( MBEDTLS_ERR_ASN1_INVALID_LENGTH );
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135 |
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136 | *val = ( **p != 0 ) ? 1 : 0;
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137 | (*p)++;
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138 |
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139 | return( 0 );
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140 | }
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141 |
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142 | int mbedtls_asn1_get_int( unsigned char **p,
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143 | const unsigned char *end,
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144 | int *val )
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145 | {
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146 | int ret;
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147 | size_t len;
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148 |
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149 | if( ( ret = mbedtls_asn1_get_tag( p, end, &len, MBEDTLS_ASN1_INTEGER ) ) != 0 )
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150 | return( ret );
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151 |
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152 | if( len == 0 || len > sizeof( int ) || ( **p & 0x80 ) != 0 )
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153 | return( MBEDTLS_ERR_ASN1_INVALID_LENGTH );
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154 |
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155 | *val = 0;
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156 |
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157 | while( len-- > 0 )
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158 | {
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159 | *val = ( *val << 8 ) | **p;
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160 | (*p)++;
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161 | }
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162 |
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163 | return( 0 );
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164 | }
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165 |
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166 | #if defined(MBEDTLS_BIGNUM_C)
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167 | int mbedtls_asn1_get_mpi( unsigned char **p,
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168 | const unsigned char *end,
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169 | mbedtls_mpi *X )
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170 | {
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171 | int ret;
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172 | size_t len;
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173 |
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174 | if( ( ret = mbedtls_asn1_get_tag( p, end, &len, MBEDTLS_ASN1_INTEGER ) ) != 0 )
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175 | return( ret );
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176 |
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177 | ret = mbedtls_mpi_read_binary( X, *p, len );
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178 |
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179 | *p += len;
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180 |
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181 | return( ret );
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182 | }
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183 | #endif /* MBEDTLS_BIGNUM_C */
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184 |
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185 | int mbedtls_asn1_get_bitstring( unsigned char **p, const unsigned char *end,
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186 | mbedtls_asn1_bitstring *bs)
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187 | {
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188 | int ret;
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189 |
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190 | /* Certificate type is a single byte bitstring */
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191 | if( ( ret = mbedtls_asn1_get_tag( p, end, &bs->len, MBEDTLS_ASN1_BIT_STRING ) ) != 0 )
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192 | return( ret );
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193 |
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194 | /* Check length, subtract one for actual bit string length */
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195 | if( bs->len < 1 )
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196 | return( MBEDTLS_ERR_ASN1_OUT_OF_DATA );
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197 | bs->len -= 1;
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198 |
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199 | /* Get number of unused bits, ensure unused bits <= 7 */
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200 | bs->unused_bits = **p;
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201 | if( bs->unused_bits > 7 )
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202 | return( MBEDTLS_ERR_ASN1_INVALID_LENGTH );
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203 | (*p)++;
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204 |
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205 | /* Get actual bitstring */
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206 | bs->p = *p;
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207 | *p += bs->len;
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208 |
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209 | if( *p != end )
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210 | return( MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );
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211 |
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212 | return( 0 );
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213 | }
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214 |
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215 | /*
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216 | * Get a bit string without unused bits
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217 | */
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218 | int mbedtls_asn1_get_bitstring_null( unsigned char **p, const unsigned char *end,
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219 | size_t *len )
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220 | {
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221 | int ret;
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222 |
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223 | if( ( ret = mbedtls_asn1_get_tag( p, end, len, MBEDTLS_ASN1_BIT_STRING ) ) != 0 )
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224 | return( ret );
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225 |
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226 | if( (*len)-- < 2 || *(*p)++ != 0 )
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227 | return( MBEDTLS_ERR_ASN1_INVALID_DATA );
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228 |
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229 | return( 0 );
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230 | }
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231 |
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232 |
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233 |
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234 | /*
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235 | * Parses and splits an ASN.1 "SEQUENCE OF <tag>"
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236 | */
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237 | int mbedtls_asn1_get_sequence_of( unsigned char **p,
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238 | const unsigned char *end,
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239 | mbedtls_asn1_sequence *cur,
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240 | int tag)
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241 | {
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242 | int ret;
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243 | size_t len;
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244 | mbedtls_asn1_buf *buf;
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245 |
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246 | /* Get main sequence tag */
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247 | if( ( ret = mbedtls_asn1_get_tag( p, end, &len,
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248 | MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )
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249 | return( ret );
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250 |
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251 | if( *p + len != end )
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252 | return( MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );
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253 |
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254 | while( *p < end )
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255 | {
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256 | buf = &(cur->buf);
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257 | buf->tag = **p;
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258 |
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259 | if( ( ret = mbedtls_asn1_get_tag( p, end, &buf->len, tag ) ) != 0 )
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260 | return( ret );
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261 |
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262 | buf->p = *p;
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263 | *p += buf->len;
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264 |
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265 | /* Allocate and assign next pointer */
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266 | if( *p < end )
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267 | {
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268 | cur->next = (mbedtls_asn1_sequence*)mbedtls_calloc( 1,
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269 | sizeof( mbedtls_asn1_sequence ) );
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270 |
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271 | if( cur->next == NULL )
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272 | return( MBEDTLS_ERR_ASN1_ALLOC_FAILED );
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273 |
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274 | cur = cur->next;
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275 | }
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276 | }
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277 |
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278 | /* Set final sequence entry's next pointer to NULL */
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279 | cur->next = NULL;
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280 |
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281 | if( *p != end )
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282 | return( MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );
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283 |
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284 | return( 0 );
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285 | }
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286 |
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287 | int mbedtls_asn1_get_alg( unsigned char **p,
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288 | const unsigned char *end,
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289 | mbedtls_asn1_buf *alg, mbedtls_asn1_buf *params )
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290 | {
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291 | int ret;
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292 | size_t len;
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293 |
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294 | if( ( ret = mbedtls_asn1_get_tag( p, end, &len,
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295 | MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )
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296 | return( ret );
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297 |
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298 | if( ( end - *p ) < 1 )
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299 | return( MBEDTLS_ERR_ASN1_OUT_OF_DATA );
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300 |
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301 | alg->tag = **p;
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302 | end = *p + len;
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303 |
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304 | if( ( ret = mbedtls_asn1_get_tag( p, end, &alg->len, MBEDTLS_ASN1_OID ) ) != 0 )
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305 | return( ret );
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306 |
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307 | alg->p = *p;
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308 | *p += alg->len;
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309 |
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310 | if( *p == end )
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311 | {
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312 | mbedtls_platform_zeroize( params, sizeof(mbedtls_asn1_buf) );
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313 | return( 0 );
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314 | }
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315 |
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316 | params->tag = **p;
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317 | (*p)++;
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318 |
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319 | if( ( ret = mbedtls_asn1_get_len( p, end, ¶ms->len ) ) != 0 )
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320 | return( ret );
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321 |
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322 | params->p = *p;
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323 | *p += params->len;
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324 |
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325 | if( *p != end )
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326 | return( MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );
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327 |
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328 | return( 0 );
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329 | }
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330 |
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331 | int mbedtls_asn1_get_alg_null( unsigned char **p,
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332 | const unsigned char *end,
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333 | mbedtls_asn1_buf *alg )
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334 | {
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335 | int ret;
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336 | mbedtls_asn1_buf params;
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337 |
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338 | memset( ¶ms, 0, sizeof(mbedtls_asn1_buf) );
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339 |
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340 | if( ( ret = mbedtls_asn1_get_alg( p, end, alg, ¶ms ) ) != 0 )
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341 | return( ret );
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342 |
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343 | if( ( params.tag != MBEDTLS_ASN1_NULL && params.tag != 0 ) || params.len != 0 )
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344 | return( MBEDTLS_ERR_ASN1_INVALID_DATA );
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345 |
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346 | return( 0 );
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347 | }
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348 |
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349 | void mbedtls_asn1_free_named_data( mbedtls_asn1_named_data *cur )
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350 | {
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351 | if( cur == NULL )
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352 | return;
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353 |
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354 | mbedtls_free( cur->oid.p );
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355 | mbedtls_free( cur->val.p );
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356 |
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357 | mbedtls_platform_zeroize( cur, sizeof( mbedtls_asn1_named_data ) );
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358 | }
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359 |
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360 | void mbedtls_asn1_free_named_data_list( mbedtls_asn1_named_data **head )
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361 | {
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362 | mbedtls_asn1_named_data *cur;
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363 |
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364 | while( ( cur = *head ) != NULL )
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365 | {
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366 | *head = cur->next;
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367 | mbedtls_asn1_free_named_data( cur );
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368 | mbedtls_free( cur );
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369 | }
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370 | }
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371 |
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372 | mbedtls_asn1_named_data *mbedtls_asn1_find_named_data( mbedtls_asn1_named_data *list,
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373 | const char *oid, size_t len )
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374 | {
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375 | while( list != NULL )
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376 | {
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377 | if( list->oid.len == len &&
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378 | memcmp( list->oid.p, oid, len ) == 0 )
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379 | {
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380 | break;
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381 | }
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382 |
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383 | list = list->next;
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384 | }
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385 |
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386 | return( list );
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387 | }
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388 |
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389 | #endif /* MBEDTLS_ASN1_PARSE_C */
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