text: /*
   *  Generic ASN.1 parsing
   *
   *  Copyright (C) 2006-2014, 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.
   */
  
  #if !defined(POLARSSL_CONFIG_FILE)
  #include "polarssl/config.h"
  #else
  #include POLARSSL_CONFIG_FILE
  #endif
  
  #if defined(POLARSSL_ASN1_PARSE_C)
  
  #include "polarssl/asn1.h"
  
  #if defined(POLARSSL_BIGNUM_C)
  #include "polarssl/bignum.h"
  #endif
  
  #if defined(POLARSSL_PLATFORM_C)
  #include "polarssl/platform.h"
  #else
  #define polarssl_malloc     malloc
  #define polarssl_free       free
  #endif
  
  #include <string.h>
  #include <stdlib.h>
  
  /*
   * ASN.1 DER decoding routines
   */
  SSL_ROM_TEXT_SECTION
  int asn1_get_len( unsigned char **p,
                    const unsigned char *end,
                    size_t *len )
  {
      if( ( end - *p ) < 1 )
          return( POLARSSL_ERR_ASN1_OUT_OF_DATA );
  
      if( ( **p & 0x80 ) == 0 )
          *len = *(*p)++;
      else
      {
          switch( **p & 0x7F )
          {
          case 1:
              if( ( end - *p ) < 2 )
                  return( POLARSSL_ERR_ASN1_OUT_OF_DATA );
  
              *len = (*p)[1];
              (*p) += 2;
              break;
  
          case 2:
              if( ( end - *p ) < 3 )
                  return( POLARSSL_ERR_ASN1_OUT_OF_DATA );
  
              *len = ( (*p)[1] << 8 ) | (*p)[2];
              (*p) += 3;
              break;
  
          case 3:
              if( ( end - *p ) < 4 )
                  return( POLARSSL_ERR_ASN1_OUT_OF_DATA );
  
              *len = ( (*p)[1] << 16 ) | ( (*p)[2] << 8 ) | (*p)[3];
              (*p) += 4;
              break;
  
          case 4:
              if( ( end - *p ) < 5 )
                  return( POLARSSL_ERR_ASN1_OUT_OF_DATA );
  
              *len = ( (*p)[1] << 24 ) | ( (*p)[2] << 16 ) | ( (*p)[3] << 8 ) |
                     (*p)[4];
              (*p) += 5;
              break;
  
          default:
              return( POLARSSL_ERR_ASN1_INVALID_LENGTH );
          }
      }
  
      if( *len > (size_t) ( end - *p ) )
          return( POLARSSL_ERR_ASN1_OUT_OF_DATA );
  
      return( 0 );
  }
  
  SSL_ROM_TEXT_SECTION
  int asn1_get_tag( unsigned char **p,
                    const unsigned char *end,
                    size_t *len, int tag )
  {
      if( ( end - *p ) < 1 )
          return( POLARSSL_ERR_ASN1_OUT_OF_DATA );
  
      if( **p != tag )
          return( POLARSSL_ERR_ASN1_UNEXPECTED_TAG );
  
      (*p)++;
  
      return( asn1_get_len( p, end, len ) );
  }
  
  SSL_ROM_TEXT_SECTION
  int asn1_get_bool( unsigned char **p,
                     const unsigned char *end,
                     int *val )
  {
      int ret;
      size_t len;
  
      if( ( ret = asn1_get_tag( p, end, &len, ASN1_BOOLEAN ) ) != 0 )
          return( ret );
  
      if( len != 1 )
          return( POLARSSL_ERR_ASN1_INVALID_LENGTH );
  
      *val = ( **p != 0 ) ? 1 : 0;
      (*p)++;
  
      return( 0 );
  }
  
  SSL_ROM_TEXT_SECTION
  int asn1_get_int( unsigned char **p,
                    const unsigned char *end,
                    int *val )
  {
      int ret;
      size_t len;
  
      if( ( ret = asn1_get_tag( p, end, &len, ASN1_INTEGER ) ) != 0 )
          return( ret );
  
      if( len > sizeof( int ) || ( **p & 0x80 ) != 0 )
          return( POLARSSL_ERR_ASN1_INVALID_LENGTH );
  
      *val = 0;
  
      while( len-- > 0 )
      {
          *val = ( *val << 8 ) | **p;
          (*p)++;
      }
  
      return( 0 );
  }
  
  #if defined(POLARSSL_BIGNUM_C)
  SSL_ROM_TEXT_SECTION
  int asn1_get_mpi( unsigned char **p,
                    const unsigned char *end,
                    mpi *X )
  {
      int ret;
      size_t len;
  
      if( ( ret = asn1_get_tag( p, end, &len, ASN1_INTEGER ) ) != 0 )
          return( ret );
  
      ret = mpi_read_binary( X, *p, len );
  
      *p += len;
  
      return( ret );
  }
  #endif /* POLARSSL_BIGNUM_C */
  
  SSL_ROM_TEXT_SECTION
  int asn1_get_bitstring( unsigned char **p, const unsigned char *end,
                          asn1_bitstring *bs)
  {
      int ret;
  
      /* Certificate type is a single byte bitstring */
      if( ( ret = asn1_get_tag( p, end, &bs->len, ASN1_BIT_STRING ) ) != 0 )
          return( ret );
  
      /* Check length, subtract one for actual bit string length */
      if( bs->len < 1 )
          return( POLARSSL_ERR_ASN1_OUT_OF_DATA );
      bs->len -= 1;
  
      /* Get number of unused bits, ensure unused bits <= 7 */
      bs->unused_bits = **p;
      if( bs->unused_bits > 7 )
          return( POLARSSL_ERR_ASN1_INVALID_LENGTH );
      (*p)++;
  
      /* Get actual bitstring */
      bs->p = *p;
      *p += bs->len;
  
      if( *p != end )
          return( POLARSSL_ERR_ASN1_LENGTH_MISMATCH );
  
      return( 0 );
  }
  
  /*
   * Get a bit string without unused bits
   */
  SSL_ROM_TEXT_SECTION
  int asn1_get_bitstring_null( unsigned char **p, const unsigned char *end,
                               size_t *len )
  {
      int ret;
  
      if( ( ret = asn1_get_tag( p, end, len, ASN1_BIT_STRING ) ) != 0 )
          return( ret );
  
      if( (*len)-- < 2 || *(*p)++ != 0 )
          return( POLARSSL_ERR_ASN1_INVALID_DATA );
  
      return( 0 );
  }
  
  
  
  /*
   *  Parses and splits an ASN.1 "SEQUENCE OF <tag>"
   */
  SSL_ROM_TEXT_SECTION
  int asn1_get_sequence_of( unsigned char **p,
                            const unsigned char *end,
                            asn1_sequence *cur,
                            int tag)
  {
      int ret;
      size_t len;
      asn1_buf *buf;
  
      /* Get main sequence tag */
      if( ( ret = asn1_get_tag( p, end, &len,
              ASN1_CONSTRUCTED | ASN1_SEQUENCE ) ) != 0 )
          return( ret );
  
      if( *p + len != end )
          return( POLARSSL_ERR_ASN1_LENGTH_MISMATCH );
  
      while( *p < end )
      {
          buf = &(cur->buf);
          buf->tag = **p;
  
          if( ( ret = asn1_get_tag( p, end, &buf->len, tag ) ) != 0 )
              return( ret );
  
          buf->p = *p;
          *p += buf->len;
  
          /* Allocate and assign next pointer */
          if( *p < end )
          {
              cur->next = (asn1_sequence *) polarssl_malloc(
                   sizeof( asn1_sequence ) );
  
              if( cur->next == NULL )
                  return( POLARSSL_ERR_ASN1_MALLOC_FAILED );
  
              cur = cur->next;
          }
      }
  
      /* Set final sequence entry's next pointer to NULL */
      cur->next = NULL;
  
      if( *p != end )
          return( POLARSSL_ERR_ASN1_LENGTH_MISMATCH );
  
      return( 0 );
  }
  
  SSL_ROM_TEXT_SECTION
  int asn1_get_alg( unsigned char **p,
                    const unsigned char *end,
                    asn1_buf *alg, asn1_buf *params )
  {
      int ret;
      size_t len;
  
      if( ( ret = asn1_get_tag( p, end, &len,
              ASN1_CONSTRUCTED | ASN1_SEQUENCE ) ) != 0 )
          return( ret );
  
      if( ( end - *p ) < 1 )
          return( POLARSSL_ERR_ASN1_OUT_OF_DATA );
  
      alg->tag = **p;
      end = *p + len;
  
      if( ( ret = asn1_get_tag( p, end, &alg->len, ASN1_OID ) ) != 0 )
          return( ret );
  
      alg->p = *p;
      *p += alg->len;
  
      if( *p == end )
      {
          memset( params, 0, sizeof(asn1_buf) );
          return( 0 );
      }
  
      params->tag = **p;
      (*p)++;
  
      if( ( ret = asn1_get_len( p, end, &params->len ) ) != 0 )
          return( ret );
  
      params->p = *p;
      *p += params->len;
  
      if( *p != end )
          return( POLARSSL_ERR_ASN1_LENGTH_MISMATCH );
  
      return( 0 );
  }
  
  SSL_ROM_TEXT_SECTION
  int asn1_get_alg_null( unsigned char **p,
                         const unsigned char *end,
                         asn1_buf *alg )
  {
      int ret;
      asn1_buf params;
  
      memset( &params, 0, sizeof(asn1_buf) );
  
      if( ( ret = asn1_get_alg( p, end, alg, &params ) ) != 0 )
          return( ret );
  
      if( ( params.tag != ASN1_NULL && params.tag != 0 ) || params.len != 0 )
          return( POLARSSL_ERR_ASN1_INVALID_DATA );
  
      return( 0 );
  }
  
  SSL_ROM_TEXT_SECTION
  void asn1_free_named_data( asn1_named_data *cur )
  {
      if( cur == NULL )
          return;
  
      polarssl_free( cur->oid.p );
      polarssl_free( cur->val.p );
  
      memset( cur, 0, sizeof( asn1_named_data ) );
  }
  
  SSL_ROM_TEXT_SECTION
  void asn1_free_named_data_list( asn1_named_data **head )
  {
      asn1_named_data *cur;
  
      while( ( cur = *head ) != NULL )
      {
          *head = cur->next;
          asn1_free_named_data( cur );
          polarssl_free( cur );
      }
  }
  
  SSL_ROM_TEXT_SECTION
  asn1_named_data *asn1_find_named_data( asn1_named_data *list,
                                         const char *oid, size_t len )
  {
      while( list != NULL )
      {
          if( list->oid.len == len &&
              memcmp( list->oid.p, oid, len ) == 0 )
          {
              break;
          }
  
          list = list->next;
      }
  
      return( list );
  }
  
  #endif /* POLARSSL_ASN1_PARSE_C */
  