359 lines
9.2 KiB
C
359 lines
9.2 KiB
C
/*
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* ASN.1 buffer writing functionality
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*
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* Copyright (C) 2006-2014, Brainspark B.V.
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*
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* This file is part of PolarSSL (http://www.polarssl.org)
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* Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
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*
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* All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include "polarssl/config.h"
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#if defined(POLARSSL_ASN1_WRITE_C)
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#include "polarssl/asn1write.h"
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#if defined(POLARSSL_PLATFORM_C)
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#include "polarssl/platform.h"
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#else
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#include <stdlib.h>
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#define polarssl_malloc malloc
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#define polarssl_free free
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#endif
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int 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( POLARSSL_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( POLARSSL_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( *p - start < 3 )
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return( POLARSSL_ERR_ASN1_BUF_TOO_SMALL );
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// We assume we never have lengths larger than 65535 bytes
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//
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*--(*p) = len % 256;
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*--(*p) = ( len / 256 ) % 256;
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*--(*p) = 0x82;
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return( 3 );
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}
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int 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( POLARSSL_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 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 < (int) size )
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return( POLARSSL_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(POLARSSL_BIGNUM_C)
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int asn1_write_mpi( unsigned char **p, unsigned char *start, 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 = mpi_size( X );
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if( *p - start < (int) len )
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return( POLARSSL_ERR_ASN1_BUF_TOO_SMALL );
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(*p) -= len;
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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( POLARSSL_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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ASN1_CHK_ADD( len, asn1_write_len( p, start, len ) );
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ASN1_CHK_ADD( len, asn1_write_tag( p, start, ASN1_INTEGER ) );
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return( (int) len );
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}
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#endif /* POLARSSL_BIGNUM_C */
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int 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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ASN1_CHK_ADD( len, asn1_write_len( p, start, 0) );
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ASN1_CHK_ADD( len, asn1_write_tag( p, start, ASN1_NULL ) );
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return( (int) len );
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}
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int 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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ASN1_CHK_ADD( len, asn1_write_raw_buffer( p, start,
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(const unsigned char *) oid, oid_len ) );
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ASN1_CHK_ADD( len , asn1_write_len( p, start, len ) );
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ASN1_CHK_ADD( len , asn1_write_tag( p, start, ASN1_OID ) );
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return( (int) len );
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}
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int 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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ASN1_CHK_ADD( len, asn1_write_null( p, start ) );
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else
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len += par_len;
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ASN1_CHK_ADD( len, asn1_write_oid( p, start, oid, oid_len ) );
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ASN1_CHK_ADD( len, asn1_write_len( p, start, len ) );
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ASN1_CHK_ADD( len, asn1_write_tag( p, start,
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ASN1_CONSTRUCTED | ASN1_SEQUENCE ) );
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return( (int) len );
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}
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int 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( POLARSSL_ERR_ASN1_BUF_TOO_SMALL );
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*--(*p) = (boolean) ? 1 : 0;
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len++;
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ASN1_CHK_ADD( len, asn1_write_len( p, start, len ) );
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ASN1_CHK_ADD( len, asn1_write_tag( p, start, ASN1_BOOLEAN ) );
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return( (int) len );
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}
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int 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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// TODO negative values and values larger than 128
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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( *p - start < 1 )
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return( POLARSSL_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( POLARSSL_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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ASN1_CHK_ADD( len, asn1_write_len( p, start, len ) );
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ASN1_CHK_ADD( len, asn1_write_tag( p, start, ASN1_INTEGER ) );
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return( (int) len );
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}
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int 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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int ret;
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size_t len = 0;
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ASN1_CHK_ADD( len, asn1_write_raw_buffer( p, start,
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(const unsigned char *) text, text_len ) );
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ASN1_CHK_ADD( len, asn1_write_len( p, start, len ) );
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ASN1_CHK_ADD( len, asn1_write_tag( p, start, ASN1_PRINTABLE_STRING ) );
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return( (int) len );
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}
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int 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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int ret;
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size_t len = 0;
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ASN1_CHK_ADD( len, asn1_write_raw_buffer( p, start,
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(const unsigned char *) text, text_len ) );
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ASN1_CHK_ADD( len, asn1_write_len( p, start, len ) );
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ASN1_CHK_ADD( len, asn1_write_tag( p, start, ASN1_IA5_STRING ) );
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return( (int) len );
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}
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int 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, size;
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size = ( bits / 8 ) + ( ( bits % 8 ) ? 1 : 0 );
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// Calculate byte length
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//
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if( *p - start < (int) size + 1 )
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return( POLARSSL_ERR_ASN1_BUF_TOO_SMALL );
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len = size + 1;
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(*p) -= size;
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memcpy( *p, buf, size );
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// Write unused bits
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//
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*--(*p) = (unsigned char) (size * 8 - bits);
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ASN1_CHK_ADD( len, asn1_write_len( p, start, len ) );
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ASN1_CHK_ADD( len, asn1_write_tag( p, start, ASN1_BIT_STRING ) );
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return( (int) len );
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}
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int 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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ASN1_CHK_ADD( len, asn1_write_raw_buffer( p, start, buf, size ) );
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ASN1_CHK_ADD( len, asn1_write_len( p, start, len ) );
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ASN1_CHK_ADD( len, asn1_write_tag( p, start, ASN1_OCTET_STRING ) );
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return( (int) len );
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}
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asn1_named_data *asn1_store_named_data( 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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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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if( ( cur = polarssl_malloc( sizeof(asn1_named_data) ) ) == NULL )
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return( NULL );
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memset( cur, 0, sizeof(asn1_named_data) );
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cur->oid.len = oid_len;
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cur->oid.p = polarssl_malloc( oid_len );
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if( cur->oid.p == NULL )
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{
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polarssl_free( cur );
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return( NULL );
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}
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cur->val.len = val_len;
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cur->val.p = polarssl_malloc( val_len );
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if( cur->val.p == NULL )
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{
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polarssl_free( cur->oid.p );
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polarssl_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->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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// Enlarge existing value buffer if needed
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//
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polarssl_free( cur->val.p );
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cur->val.p = NULL;
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cur->val.len = val_len;
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cur->val.p = polarssl_malloc( val_len );
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if( cur->val.p == NULL )
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{
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polarssl_free( cur->oid.p );
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polarssl_free( cur );
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return( NULL );
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}
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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
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