[398] | 1 | /*
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| 2 | * ASN.1 buffer writing functionality
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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_WRITE_C)
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| 29 |
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| 30 | #include "mbedtls/asn1write.h"
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| 31 |
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| 32 | #include <string.h>
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| 33 |
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| 34 | #if defined(MBEDTLS_PLATFORM_C)
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| 35 | #include "mbedtls/platform.h"
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| 36 | #else
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| 37 | #include <stdlib.h>
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| 38 | #define mbedtls_calloc calloc
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| 39 | #define mbedtls_free free
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| 40 | #endif
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| 41 |
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| 42 | int mbedtls_asn1_write_len( unsigned char **p, unsigned char *start, size_t len )
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| 43 | {
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| 44 | if( len < 0x80 )
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| 45 | {
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| 46 | if( *p - start < 1 )
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| 47 | return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
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| 48 |
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| 49 | *--(*p) = (unsigned char) len;
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| 50 | return( 1 );
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| 51 | }
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| 52 |
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| 53 | if( len <= 0xFF )
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| 54 | {
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| 55 | if( *p - start < 2 )
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| 56 | return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
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| 57 |
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| 58 | *--(*p) = (unsigned char) len;
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| 59 | *--(*p) = 0x81;
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| 60 | return( 2 );
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| 61 | }
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| 62 |
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| 63 | if( len <= 0xFFFF )
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| 64 | {
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| 65 | if( *p - start < 3 )
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| 66 | return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
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| 67 |
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| 68 | *--(*p) = ( len ) & 0xFF;
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| 69 | *--(*p) = ( len >> 8 ) & 0xFF;
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| 70 | *--(*p) = 0x82;
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| 71 | return( 3 );
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| 72 | }
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| 73 |
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| 74 | if( len <= 0xFFFFFF )
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| 75 | {
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| 76 | if( *p - start < 4 )
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| 77 | return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
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| 78 |
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| 79 | *--(*p) = ( len ) & 0xFF;
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| 80 | *--(*p) = ( len >> 8 ) & 0xFF;
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| 81 | *--(*p) = ( len >> 16 ) & 0xFF;
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| 82 | *--(*p) = 0x83;
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| 83 | return( 4 );
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| 84 | }
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| 85 |
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| 86 | #if SIZE_MAX > 0xFFFFFFFF
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| 87 | if( len <= 0xFFFFFFFF )
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| 88 | #endif
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| 89 | {
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| 90 | if( *p - start < 5 )
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| 91 | return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
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| 92 |
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| 93 | *--(*p) = ( len ) & 0xFF;
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| 94 | *--(*p) = ( len >> 8 ) & 0xFF;
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| 95 | *--(*p) = ( len >> 16 ) & 0xFF;
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| 96 | *--(*p) = ( len >> 24 ) & 0xFF;
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| 97 | *--(*p) = 0x84;
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| 98 | return( 5 );
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| 99 | }
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| 100 |
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| 101 | #if SIZE_MAX > 0xFFFFFFFF
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| 102 | return( MBEDTLS_ERR_ASN1_INVALID_LENGTH );
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| 103 | #endif
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| 104 | }
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| 105 |
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| 106 | int mbedtls_asn1_write_tag( unsigned char **p, unsigned char *start, unsigned char tag )
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| 107 | {
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| 108 | if( *p - start < 1 )
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| 109 | return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
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| 110 |
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| 111 | *--(*p) = tag;
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| 112 |
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| 113 | return( 1 );
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| 114 | }
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| 115 |
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| 116 | int mbedtls_asn1_write_raw_buffer( unsigned char **p, unsigned char *start,
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| 117 | const unsigned char *buf, size_t size )
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| 118 | {
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| 119 | size_t len = 0;
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| 120 |
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| 121 | if( *p < start || (size_t)( *p - start ) < size )
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| 122 | return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
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| 123 |
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| 124 | len = size;
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| 125 | (*p) -= len;
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| 126 | memcpy( *p, buf, len );
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| 127 |
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| 128 | return( (int) len );
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| 129 | }
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| 130 |
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| 131 | #if defined(MBEDTLS_BIGNUM_C)
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| 132 | int mbedtls_asn1_write_mpi( unsigned char **p, unsigned char *start, const mbedtls_mpi *X )
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| 133 | {
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| 134 | int ret;
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| 135 | size_t len = 0;
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| 136 |
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| 137 | // Write the MPI
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| 138 | //
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| 139 | len = mbedtls_mpi_size( X );
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| 140 |
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| 141 | if( *p < start || (size_t)( *p - start ) < len )
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| 142 | return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
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| 143 |
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| 144 | (*p) -= len;
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| 145 | MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( X, *p, len ) );
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| 146 |
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| 147 | // DER format assumes 2s complement for numbers, so the leftmost bit
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| 148 | // should be 0 for positive numbers and 1 for negative numbers.
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| 149 | //
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| 150 | if( X->s ==1 && **p & 0x80 )
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| 151 | {
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| 152 | if( *p - start < 1 )
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| 153 | return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
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| 154 |
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| 155 | *--(*p) = 0x00;
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| 156 | len += 1;
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| 157 | }
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| 158 |
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| 159 | MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
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| 160 | MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_INTEGER ) );
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| 161 |
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| 162 | ret = (int) len;
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| 163 |
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| 164 | cleanup:
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| 165 | return( ret );
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| 166 | }
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| 167 | #endif /* MBEDTLS_BIGNUM_C */
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| 168 |
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| 169 | int mbedtls_asn1_write_null( unsigned char **p, unsigned char *start )
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| 170 | {
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| 171 | int ret;
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| 172 | size_t len = 0;
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| 173 |
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| 174 | // Write NULL
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| 175 | //
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| 176 | MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, 0) );
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| 177 | MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_NULL ) );
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| 178 |
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| 179 | return( (int) len );
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| 180 | }
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| 181 |
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| 182 | int mbedtls_asn1_write_oid( unsigned char **p, unsigned char *start,
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| 183 | const char *oid, size_t oid_len )
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| 184 | {
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| 185 | int ret;
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| 186 | size_t len = 0;
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| 187 |
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| 188 | MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_raw_buffer( p, start,
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| 189 | (const unsigned char *) oid, oid_len ) );
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| 190 | MBEDTLS_ASN1_CHK_ADD( len , mbedtls_asn1_write_len( p, start, len ) );
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| 191 | MBEDTLS_ASN1_CHK_ADD( len , mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_OID ) );
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| 192 |
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| 193 | return( (int) len );
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| 194 | }
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| 195 |
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| 196 | int mbedtls_asn1_write_algorithm_identifier( unsigned char **p, unsigned char *start,
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| 197 | const char *oid, size_t oid_len,
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| 198 | size_t par_len )
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| 199 | {
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| 200 | int ret;
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| 201 | size_t len = 0;
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| 202 |
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| 203 | if( par_len == 0 )
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| 204 | MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_null( p, start ) );
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| 205 | else
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| 206 | len += par_len;
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| 207 |
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| 208 | MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_oid( p, start, oid, oid_len ) );
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| 209 |
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| 210 | MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
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| 211 | MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start,
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| 212 | MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) );
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| 213 |
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| 214 | return( (int) len );
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| 215 | }
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| 216 |
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| 217 | int mbedtls_asn1_write_bool( unsigned char **p, unsigned char *start, int boolean )
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| 218 | {
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| 219 | int ret;
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| 220 | size_t len = 0;
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| 221 |
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| 222 | if( *p - start < 1 )
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| 223 | return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
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| 224 |
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| 225 | *--(*p) = (boolean) ? 255 : 0;
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| 226 | len++;
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| 227 |
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| 228 | MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
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| 229 | MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_BOOLEAN ) );
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| 230 |
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| 231 | return( (int) len );
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| 232 | }
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| 233 |
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| 234 | int mbedtls_asn1_write_int( unsigned char **p, unsigned char *start, int val )
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| 235 | {
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| 236 | int ret;
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| 237 | size_t len = 0;
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| 238 |
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| 239 | if( *p - start < 1 )
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| 240 | return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
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| 241 |
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| 242 | len += 1;
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| 243 | *--(*p) = val;
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| 244 |
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| 245 | if( val > 0 && **p & 0x80 )
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| 246 | {
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| 247 | if( *p - start < 1 )
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| 248 | return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
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| 249 |
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| 250 | *--(*p) = 0x00;
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| 251 | len += 1;
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| 252 | }
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| 253 |
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| 254 | MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
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| 255 | MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_INTEGER ) );
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| 256 |
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| 257 | return( (int) len );
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| 258 | }
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| 259 |
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| 260 | int mbedtls_asn1_write_tagged_string( unsigned char **p, unsigned char *start, int tag,
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| 261 | const char *text, size_t text_len )
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| 262 | {
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| 263 | int ret;
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| 264 | size_t len = 0;
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| 265 |
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| 266 | MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_raw_buffer( p, start,
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| 267 | (const unsigned char *) text, text_len ) );
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| 268 |
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| 269 | MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
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| 270 | MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, tag ) );
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| 271 |
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| 272 | return( (int) len );
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| 273 | }
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| 274 |
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| 275 | int mbedtls_asn1_write_utf8_string( unsigned char **p, unsigned char *start,
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| 276 | const char *text, size_t text_len )
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| 277 | {
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| 278 | return( mbedtls_asn1_write_tagged_string(p, start, MBEDTLS_ASN1_UTF8_STRING, text, text_len) );
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| 279 | }
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| 280 |
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| 281 | int mbedtls_asn1_write_printable_string( unsigned char **p, unsigned char *start,
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| 282 | const char *text, size_t text_len )
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| 283 | {
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| 284 | return( mbedtls_asn1_write_tagged_string(p, start, MBEDTLS_ASN1_PRINTABLE_STRING, text, text_len) );
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| 285 | }
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| 286 |
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| 287 | int mbedtls_asn1_write_ia5_string( unsigned char **p, unsigned char *start,
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| 288 | const char *text, size_t text_len )
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| 289 | {
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| 290 | return( mbedtls_asn1_write_tagged_string(p, start, MBEDTLS_ASN1_IA5_STRING, text, text_len) );
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| 291 | }
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| 292 |
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| 293 | int mbedtls_asn1_write_bitstring( unsigned char **p, unsigned char *start,
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| 294 | const unsigned char *buf, size_t bits )
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| 295 | {
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| 296 | int ret;
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| 297 | size_t len = 0;
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| 298 | size_t unused_bits, byte_len;
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| 299 |
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| 300 | byte_len = ( bits + 7 ) / 8;
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| 301 | unused_bits = ( byte_len * 8 ) - bits;
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| 302 |
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| 303 | if( *p < start || (size_t)( *p - start ) < byte_len + 1 )
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| 304 | return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
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| 305 |
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| 306 | len = byte_len + 1;
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| 307 |
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| 308 | /* Write the bitstring. Ensure the unused bits are zeroed */
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| 309 | if( byte_len > 0 )
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| 310 | {
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| 311 | byte_len--;
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| 312 | *--( *p ) = buf[byte_len] & ~( ( 0x1 << unused_bits ) - 1 );
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| 313 | ( *p ) -= byte_len;
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| 314 | memcpy( *p, buf, byte_len );
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| 315 | }
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| 316 |
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| 317 | /* Write unused bits */
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| 318 | *--( *p ) = (unsigned char)unused_bits;
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| 319 |
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| 320 | MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
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| 321 | MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_BIT_STRING ) );
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| 322 |
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| 323 | return( (int) len );
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| 324 | }
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| 325 |
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| 326 | int mbedtls_asn1_write_octet_string( unsigned char **p, unsigned char *start,
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| 327 | const unsigned char *buf, size_t size )
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| 328 | {
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| 329 | int ret;
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| 330 | size_t len = 0;
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| 331 |
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| 332 | MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_raw_buffer( p, start, buf, size ) );
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| 333 |
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| 334 | MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
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| 335 | MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_OCTET_STRING ) );
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| 336 |
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| 337 | return( (int) len );
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| 338 | }
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| 339 |
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| 340 |
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| 341 | /* This is a copy of the ASN.1 parsing function mbedtls_asn1_find_named_data(),
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| 342 | * which is replicated to avoid a dependency ASN1_WRITE_C on ASN1_PARSE_C. */
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| 343 | static mbedtls_asn1_named_data *asn1_find_named_data(
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| 344 | mbedtls_asn1_named_data *list,
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| 345 | const char *oid, size_t len )
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| 346 | {
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| 347 | while( list != NULL )
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| 348 | {
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| 349 | if( list->oid.len == len &&
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| 350 | memcmp( list->oid.p, oid, len ) == 0 )
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| 351 | {
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| 352 | break;
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| 353 | }
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| 354 |
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| 355 | list = list->next;
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| 356 | }
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| 357 |
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| 358 | return( list );
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| 359 | }
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| 360 |
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| 361 | mbedtls_asn1_named_data *mbedtls_asn1_store_named_data(
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| 362 | mbedtls_asn1_named_data **head,
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| 363 | const char *oid, size_t oid_len,
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| 364 | const unsigned char *val,
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| 365 | size_t val_len )
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| 366 | {
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| 367 | mbedtls_asn1_named_data *cur;
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| 368 |
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| 369 | if( ( cur = asn1_find_named_data( *head, oid, oid_len ) ) == NULL )
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| 370 | {
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| 371 | // Add new entry if not present yet based on OID
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| 372 | //
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| 373 | cur = (mbedtls_asn1_named_data*)mbedtls_calloc( 1,
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| 374 | sizeof(mbedtls_asn1_named_data) );
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| 375 | if( cur == NULL )
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| 376 | return( NULL );
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| 377 |
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| 378 | cur->oid.len = oid_len;
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| 379 | cur->oid.p = mbedtls_calloc( 1, oid_len );
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| 380 | if( cur->oid.p == NULL )
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| 381 | {
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| 382 | mbedtls_free( cur );
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| 383 | return( NULL );
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| 384 | }
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| 385 |
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| 386 | memcpy( cur->oid.p, oid, oid_len );
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| 387 |
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| 388 | cur->val.len = val_len;
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| 389 | cur->val.p = mbedtls_calloc( 1, val_len );
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| 390 | if( cur->val.p == NULL )
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| 391 | {
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| 392 | mbedtls_free( cur->oid.p );
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| 393 | mbedtls_free( cur );
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| 394 | return( NULL );
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| 395 | }
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| 396 |
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| 397 | cur->next = *head;
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| 398 | *head = cur;
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| 399 | }
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| 400 | else if( cur->val.len < val_len )
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| 401 | {
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| 402 | /*
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| 403 | * Enlarge existing value buffer if needed
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| 404 | * Preserve old data until the allocation succeeded, to leave list in
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| 405 | * a consistent state in case allocation fails.
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| 406 | */
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| 407 | void *p = mbedtls_calloc( 1, val_len );
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| 408 | if( p == NULL )
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| 409 | return( NULL );
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| 410 |
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| 411 | mbedtls_free( cur->val.p );
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| 412 | cur->val.p = p;
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| 413 | cur->val.len = val_len;
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| 414 | }
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| 415 |
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| 416 | if( val != NULL )
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| 417 | memcpy( cur->val.p, val, val_len );
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| 418 |
|
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| 419 | return( cur );
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| 420 | }
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| 421 | #endif /* MBEDTLS_ASN1_WRITE_C */
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