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polarssl/library/asn1write.c

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/*
* ASN.1 buffer writing functionality
*
* Copyright (C) 2006-2012, Brainspark B.V.
*
* This file is part of PolarSSL (http://www.polarssl.org)
* Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
*
* All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "polarssl/config.h"
#if defined(POLARSSL_ASN1_WRITE_C)
#include "polarssl/asn1write.h"
#if defined(POLARSSL_MEMORY_C)
#include "polarssl/memory.h"
#else
#include <stdlib.h>
#define polarssl_malloc malloc
#define polarssl_free free
#endif
int asn1_write_len( unsigned char **p, unsigned char *start, size_t len )
{
if( len < 0x80 )
{
if( *p - start < 1 )
return( POLARSSL_ERR_ASN1_BUF_TOO_SMALL );
*--(*p) = (unsigned char) len;
return( 1 );
}
if( len <= 0xFF )
{
if( *p - start < 2 )
return( POLARSSL_ERR_ASN1_BUF_TOO_SMALL );
*--(*p) = (unsigned char) len;
*--(*p) = 0x81;
return( 2 );
}
if( *p - start < 3 )
return( POLARSSL_ERR_ASN1_BUF_TOO_SMALL );
// We assume we never have lengths larger than 65535 bytes
//
*--(*p) = len % 256;
*--(*p) = ( len / 256 ) % 256;
*--(*p) = 0x82;
return( 3 );
}
int asn1_write_tag( unsigned char **p, unsigned char *start, unsigned char tag )
{
if( *p - start < 1 )
return( POLARSSL_ERR_ASN1_BUF_TOO_SMALL );
*--(*p) = tag;
return( 1 );
}
int asn1_write_raw_buffer( unsigned char **p, unsigned char *start,
const unsigned char *buf, size_t size )
{
size_t len = 0;
if( *p - start < (int) size )
return( POLARSSL_ERR_ASN1_BUF_TOO_SMALL );
len = size;
(*p) -= len;
memcpy( *p, buf, len );
return( (int) len );
}
#if defined(POLARSSL_BIGNUM_C)
int asn1_write_mpi( unsigned char **p, unsigned char *start, mpi *X )
{
int ret;
size_t len = 0;
// Write the MPI
//
len = mpi_size( X );
if( *p - start < (int) len )
return( POLARSSL_ERR_ASN1_BUF_TOO_SMALL );
(*p) -= len;
mpi_write_binary( X, *p, len );
// DER format assumes 2s complement for numbers, so the leftmost bit
// should be 0 for positive numbers and 1 for negative numbers.
//
if ( X->s ==1 && **p & 0x80 )
{
if( *p - start < 1 )
return( POLARSSL_ERR_ASN1_BUF_TOO_SMALL );
*--(*p) = 0x00;
len += 1;
}
ASN1_CHK_ADD( len, asn1_write_len( p, start, len ) );
ASN1_CHK_ADD( len, asn1_write_tag( p, start, ASN1_INTEGER ) );
return( (int) len );
}
#endif /* POLARSSL_BIGNUM_C */
int asn1_write_null( unsigned char **p, unsigned char *start )
{
int ret;
size_t len = 0;
// Write NULL
//
ASN1_CHK_ADD( len, asn1_write_len( p, start, 0) );
ASN1_CHK_ADD( len, asn1_write_tag( p, start, ASN1_NULL ) );
return( (int) len );
}
int asn1_write_oid( unsigned char **p, unsigned char *start,
const char *oid, size_t oid_len )
{
int ret;
size_t len = 0;
ASN1_CHK_ADD( len, asn1_write_raw_buffer( p, start,
(const unsigned char *) oid, oid_len ) );
ASN1_CHK_ADD( len , asn1_write_len( p, start, len ) );
ASN1_CHK_ADD( len , asn1_write_tag( p, start, ASN1_OID ) );
return( (int) len );
}
int asn1_write_algorithm_identifier( unsigned char **p, unsigned char *start,
const char *oid, size_t oid_len,
size_t par_len )
{
int ret;
size_t len = 0;
if( par_len == 0 )
ASN1_CHK_ADD( len, asn1_write_null( p, start ) );
else
len += par_len;
ASN1_CHK_ADD( len, asn1_write_oid( p, start, oid, oid_len ) );
ASN1_CHK_ADD( len, asn1_write_len( p, start, len ) );
ASN1_CHK_ADD( len, asn1_write_tag( p, start,
ASN1_CONSTRUCTED | ASN1_SEQUENCE ) );
return( (int) len );
}
int asn1_write_bool( unsigned char **p, unsigned char *start, int boolean )
{
int ret;
size_t len = 0;
if( *p - start < 1 )
return( POLARSSL_ERR_ASN1_BUF_TOO_SMALL );
*--(*p) = (boolean) ? 1 : 0;
len++;
ASN1_CHK_ADD( len, asn1_write_len( p, start, len ) );
ASN1_CHK_ADD( len, asn1_write_tag( p, start, ASN1_BOOLEAN ) );
return( (int) len );
}
int asn1_write_int( unsigned char **p, unsigned char *start, int val )
{
int ret;
size_t len = 0;
// TODO negative values and values larger than 128
// DER format assumes 2s complement for numbers, so the leftmost bit
// should be 0 for positive numbers and 1 for negative numbers.
//
if( *p - start < 1 )
return( POLARSSL_ERR_ASN1_BUF_TOO_SMALL );
len += 1;
*--(*p) = val;
if ( val > 0 && **p & 0x80 )
{
if( *p - start < 1 )
return( POLARSSL_ERR_ASN1_BUF_TOO_SMALL );
*--(*p) = 0x00;
len += 1;
}
ASN1_CHK_ADD( len, asn1_write_len( p, start, len ) );
ASN1_CHK_ADD( len, asn1_write_tag( p, start, ASN1_INTEGER ) );
return( (int) len );
}
int asn1_write_printable_string( unsigned char **p, unsigned char *start,
const char *text, size_t text_len )
{
int ret;
size_t len = 0;
ASN1_CHK_ADD( len, asn1_write_raw_buffer( p, start,
(const unsigned char *) text, text_len ) );
ASN1_CHK_ADD( len, asn1_write_len( p, start, len ) );
ASN1_CHK_ADD( len, asn1_write_tag( p, start, ASN1_PRINTABLE_STRING ) );
return( (int) len );
}
int asn1_write_ia5_string( unsigned char **p, unsigned char *start,
const char *text, size_t text_len )
{
int ret;
size_t len = 0;
ASN1_CHK_ADD( len, asn1_write_raw_buffer( p, start,
(const unsigned char *) text, text_len ) );
ASN1_CHK_ADD( len, asn1_write_len( p, start, len ) );
ASN1_CHK_ADD( len, asn1_write_tag( p, start, ASN1_IA5_STRING ) );
return( (int) len );
}
int asn1_write_bitstring( unsigned char **p, unsigned char *start,
const unsigned char *buf, size_t bits )
{
int ret;
size_t len = 0, size;
size = ( bits / 8 ) + ( ( bits % 8 ) ? 1 : 0 );
// Calculate byte length
//
if( *p - start < (int) size + 1 )
return( POLARSSL_ERR_ASN1_BUF_TOO_SMALL );
len = size + 1;
(*p) -= size;
memcpy( *p, buf, size );
// Write unused bits
//
*--(*p) = (unsigned char) (size * 8 - bits);
ASN1_CHK_ADD( len, asn1_write_len( p, start, len ) );
ASN1_CHK_ADD( len, asn1_write_tag( p, start, ASN1_BIT_STRING ) );
return( (int) len );
}
int asn1_write_octet_string( unsigned char **p, unsigned char *start,
const unsigned char *buf, size_t size )
{
int ret;
size_t len = 0;
ASN1_CHK_ADD( len, asn1_write_raw_buffer( p, start, buf, size ) );
ASN1_CHK_ADD( len, asn1_write_len( p, start, len ) );
ASN1_CHK_ADD( len, asn1_write_tag( p, start, ASN1_OCTET_STRING ) );
return( (int) len );
}
asn1_named_data *asn1_store_named_data( asn1_named_data **head,
const char *oid, size_t oid_len,
const unsigned char *val,
size_t val_len )
{
asn1_named_data *cur;
if( ( cur = asn1_find_named_data( *head, oid, oid_len ) ) == NULL )
{
// Add new entry if not present yet based on OID
//
if( ( cur = polarssl_malloc( sizeof(asn1_named_data) ) ) == NULL )
return( NULL );
memset( cur, 0, sizeof(asn1_named_data) );
cur->oid.len = oid_len;
cur->oid.p = polarssl_malloc( oid_len );
if( cur->oid.p == NULL )
{
polarssl_free( cur );
return( NULL );
}
cur->val.len = val_len;
cur->val.p = polarssl_malloc( val_len );
if( cur->val.p == NULL )
{
polarssl_free( cur->oid.p );
polarssl_free( cur );
return( NULL );
}
memcpy( cur->oid.p, oid, oid_len );
cur->next = *head;
*head = cur;
}
else if( cur->val.len < val_len )
{
// Enlarge existing value buffer if needed
//
polarssl_free( cur->val.p );
cur->val.p = NULL;
cur->val.len = val_len;
cur->val.p = polarssl_malloc( val_len );
if( cur->val.p == NULL )
{
polarssl_free( cur->oid.p );
polarssl_free( cur );
return( NULL );
}
}
if( val != NULL )
memcpy( cur->val.p, val, val_len );
return( cur );
}
#endif
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