422 lines
11 KiB
C
422 lines
11 KiB
C
/*
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* ASN.1 buffer writing functionality
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*
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* Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the "License"); you may
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* not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* This file is part of mbed TLS (https://tls.mbed.org)
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*/
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#if !defined(MBEDTLS_CONFIG_FILE)
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#include "mbedtls/config.h"
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#else
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#include MBEDTLS_CONFIG_FILE
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#endif
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#if defined(MBEDTLS_ASN1_WRITE_C)
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#include "mbedtls/asn1write.h"
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#include <string.h>
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#if defined(MBEDTLS_PLATFORM_C)
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#include "mbedtls/platform.h"
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#else
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#include <stdlib.h>
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#define mbedtls_calloc calloc
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#define mbedtls_free free
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#endif
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int mbedtls_asn1_write_len( unsigned char **p, unsigned char *start, size_t len )
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{
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if( len < 0x80 )
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{
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if( *p - start < 1 )
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return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
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*--(*p) = (unsigned char) len;
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return( 1 );
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}
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if( len <= 0xFF )
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{
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if( *p - start < 2 )
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return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
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*--(*p) = (unsigned char) len;
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*--(*p) = 0x81;
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return( 2 );
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}
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if( len <= 0xFFFF )
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{
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if( *p - start < 3 )
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return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
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*--(*p) = ( len ) & 0xFF;
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*--(*p) = ( len >> 8 ) & 0xFF;
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*--(*p) = 0x82;
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return( 3 );
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}
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if( len <= 0xFFFFFF )
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{
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if( *p - start < 4 )
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return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
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*--(*p) = ( len ) & 0xFF;
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*--(*p) = ( len >> 8 ) & 0xFF;
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*--(*p) = ( len >> 16 ) & 0xFF;
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*--(*p) = 0x83;
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return( 4 );
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}
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#if SIZE_MAX > 0xFFFFFFFF
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if( len <= 0xFFFFFFFF )
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#endif
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{
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if( *p - start < 5 )
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return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
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*--(*p) = ( len ) & 0xFF;
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*--(*p) = ( len >> 8 ) & 0xFF;
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*--(*p) = ( len >> 16 ) & 0xFF;
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*--(*p) = ( len >> 24 ) & 0xFF;
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*--(*p) = 0x84;
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return( 5 );
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}
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#if SIZE_MAX > 0xFFFFFFFF
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return( MBEDTLS_ERR_ASN1_INVALID_LENGTH );
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#endif
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}
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int mbedtls_asn1_write_tag( unsigned char **p, unsigned char *start, unsigned char tag )
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{
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if( *p - start < 1 )
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return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
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*--(*p) = tag;
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return( 1 );
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}
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int mbedtls_asn1_write_raw_buffer( unsigned char **p, unsigned char *start,
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const unsigned char *buf, size_t size )
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{
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size_t len = 0;
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if( *p < start || (size_t)( *p - start ) < size )
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return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
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len = size;
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(*p) -= len;
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memcpy( *p, buf, len );
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return( (int) len );
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}
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#if defined(MBEDTLS_BIGNUM_C)
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int mbedtls_asn1_write_mpi( unsigned char **p, unsigned char *start, const mbedtls_mpi *X )
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{
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int ret;
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size_t len = 0;
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// Write the MPI
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//
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len = mbedtls_mpi_size( X );
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if( *p < start || (size_t)( *p - start ) < len )
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return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
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(*p) -= len;
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MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( X, *p, len ) );
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// DER format assumes 2s complement for numbers, so the leftmost bit
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// should be 0 for positive numbers and 1 for negative numbers.
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//
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if( X->s ==1 && **p & 0x80 )
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{
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if( *p - start < 1 )
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return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
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*--(*p) = 0x00;
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len += 1;
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}
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MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
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MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_INTEGER ) );
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ret = (int) len;
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cleanup:
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return( ret );
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}
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#endif /* MBEDTLS_BIGNUM_C */
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int mbedtls_asn1_write_null( unsigned char **p, unsigned char *start )
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{
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int ret;
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size_t len = 0;
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// Write NULL
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//
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MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, 0) );
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MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_NULL ) );
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return( (int) len );
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}
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int mbedtls_asn1_write_oid( unsigned char **p, unsigned char *start,
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const char *oid, size_t oid_len )
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{
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int ret;
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size_t len = 0;
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MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_raw_buffer( p, start,
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(const unsigned char *) oid, oid_len ) );
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MBEDTLS_ASN1_CHK_ADD( len , mbedtls_asn1_write_len( p, start, len ) );
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MBEDTLS_ASN1_CHK_ADD( len , mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_OID ) );
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return( (int) len );
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}
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int mbedtls_asn1_write_algorithm_identifier( unsigned char **p, unsigned char *start,
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const char *oid, size_t oid_len,
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size_t par_len )
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{
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int ret;
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size_t len = 0;
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if( par_len == 0 )
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MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_null( p, start ) );
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else
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len += par_len;
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MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_oid( p, start, oid, oid_len ) );
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MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
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MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start,
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MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) );
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return( (int) len );
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}
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int mbedtls_asn1_write_bool( unsigned char **p, unsigned char *start, int boolean )
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{
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int ret;
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size_t len = 0;
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if( *p - start < 1 )
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return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
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*--(*p) = (boolean) ? 255 : 0;
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len++;
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MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
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MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_BOOLEAN ) );
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return( (int) len );
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}
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int mbedtls_asn1_write_int( unsigned char **p, unsigned char *start, int val )
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{
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int ret;
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size_t len = 0;
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if( *p - start < 1 )
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return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
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len += 1;
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*--(*p) = val;
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if( val > 0 && **p & 0x80 )
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{
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if( *p - start < 1 )
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return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
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*--(*p) = 0x00;
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len += 1;
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}
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MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
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MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_INTEGER ) );
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return( (int) len );
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}
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int mbedtls_asn1_write_tagged_string( unsigned char **p, unsigned char *start, int tag,
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const char *text, size_t text_len )
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{
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int ret;
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size_t len = 0;
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MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_raw_buffer( p, start,
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(const unsigned char *) text, text_len ) );
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MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
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MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, tag ) );
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return( (int) len );
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}
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int mbedtls_asn1_write_utf8_string( unsigned char **p, unsigned char *start,
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const char *text, size_t text_len )
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{
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return( mbedtls_asn1_write_tagged_string(p, start, MBEDTLS_ASN1_UTF8_STRING, text, text_len) );
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}
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int mbedtls_asn1_write_printable_string( unsigned char **p, unsigned char *start,
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const char *text, size_t text_len )
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{
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return( mbedtls_asn1_write_tagged_string(p, start, MBEDTLS_ASN1_PRINTABLE_STRING, text, text_len) );
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}
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int mbedtls_asn1_write_ia5_string( unsigned char **p, unsigned char *start,
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const char *text, size_t text_len )
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{
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return( mbedtls_asn1_write_tagged_string(p, start, MBEDTLS_ASN1_IA5_STRING, text, text_len) );
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}
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int mbedtls_asn1_write_bitstring( unsigned char **p, unsigned char *start,
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const unsigned char *buf, size_t bits )
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{
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int ret;
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size_t len = 0;
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size_t unused_bits, byte_len;
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byte_len = ( bits + 7 ) / 8;
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unused_bits = ( byte_len * 8 ) - bits;
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if( *p < start || (size_t)( *p - start ) < byte_len + 1 )
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return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
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len = byte_len + 1;
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/* Write the bitstring. Ensure the unused bits are zeroed */
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if( byte_len > 0 )
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{
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byte_len--;
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*--( *p ) = buf[byte_len] & ~( ( 0x1 << unused_bits ) - 1 );
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( *p ) -= byte_len;
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memcpy( *p, buf, byte_len );
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}
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/* Write unused bits */
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*--( *p ) = (unsigned char)unused_bits;
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MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
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MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_BIT_STRING ) );
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return( (int) len );
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}
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int mbedtls_asn1_write_octet_string( unsigned char **p, unsigned char *start,
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const unsigned char *buf, size_t size )
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{
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int ret;
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size_t len = 0;
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MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_raw_buffer( p, start, buf, size ) );
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MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
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MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_OCTET_STRING ) );
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return( (int) len );
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}
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/* This is a copy of the ASN.1 parsing function mbedtls_asn1_find_named_data(),
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* which is replicated to avoid a dependency ASN1_WRITE_C on ASN1_PARSE_C. */
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static mbedtls_asn1_named_data *asn1_find_named_data(
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mbedtls_asn1_named_data *list,
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const char *oid, size_t len )
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{
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while( list != NULL )
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{
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if( list->oid.len == len &&
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memcmp( list->oid.p, oid, len ) == 0 )
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{
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break;
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}
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list = list->next;
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}
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return( list );
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}
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mbedtls_asn1_named_data *mbedtls_asn1_store_named_data(
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mbedtls_asn1_named_data **head,
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const char *oid, size_t oid_len,
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const unsigned char *val,
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size_t val_len )
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{
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mbedtls_asn1_named_data *cur;
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if( ( cur = asn1_find_named_data( *head, oid, oid_len ) ) == NULL )
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{
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// Add new entry if not present yet based on OID
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//
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cur = (mbedtls_asn1_named_data*)mbedtls_calloc( 1,
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sizeof(mbedtls_asn1_named_data) );
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if( cur == NULL )
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return( NULL );
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cur->oid.len = oid_len;
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cur->oid.p = mbedtls_calloc( 1, oid_len );
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if( cur->oid.p == NULL )
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{
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mbedtls_free( cur );
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return( NULL );
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}
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memcpy( cur->oid.p, oid, oid_len );
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cur->val.len = val_len;
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cur->val.p = mbedtls_calloc( 1, val_len );
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if( cur->val.p == NULL )
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{
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mbedtls_free( cur->oid.p );
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mbedtls_free( cur );
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return( NULL );
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}
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cur->next = *head;
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*head = cur;
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}
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else if( cur->val.len < val_len )
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{
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/*
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* Enlarge existing value buffer if needed
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* Preserve old data until the allocation succeeded, to leave list in
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* a consistent state in case allocation fails.
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*/
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void *p = mbedtls_calloc( 1, val_len );
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if( p == NULL )
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return( NULL );
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mbedtls_free( cur->val.p );
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cur->val.p = p;
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cur->val.len = val_len;
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}
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if( val != NULL )
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memcpy( cur->val.p, val, val_len );
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return( cur );
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}
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#endif /* MBEDTLS_ASN1_WRITE_C */
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