[398] | 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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