/*
 * New driver for /dev/crypto device (aka CryptoDev)

 * Copyright (c) 2010 Katholieke Universiteit Leuven
 *
 * Author: Nikos Mavrogiannopoulos <nmav@gnutls.org>
 *
 * This file is part of linux cryptodev.
 *
 * 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 "tomcrypt.h"

/**
  @file der_encode_sequence_multi.c
  ASN.1 DER, encode a Subject Public Key structure --nmav
*/

#ifdef LTC_DER

/* AlgorithmIdentifier := SEQUENCE {
 *    algorithm OBJECT IDENTIFIER,
 *    parameters ANY DEFINED BY algorithm
 * }
 * 
 * SubjectPublicKeyInfo := SEQUENCE {
 *    algorithm AlgorithmIdentifier,
 *    subjectPublicKey BIT STRING
 * }
 */
/**
  Encode a SEQUENCE type using a VA list
  @param out    [out] Destination for data
  @param outlen [in/out] Length of buffer and resulting length of output
  @remark <...> is of the form <type, size, data> (int, unsigned long, void*)
  @return CRYPT_OK on success
*/  
int der_decode_subject_public_key_info(const unsigned char *in, unsigned long inlen,
        unsigned int algorithm, void* public_key, unsigned long* public_key_len,
        unsigned long parameters_type, ltc_asn1_list* parameters, unsigned long parameters_len)
{
   int err, len;
   oid_st oid;
   unsigned char *tmpbuf;
   unsigned long  tmpoid[16];
   ltc_asn1_list alg_id[2];
   ltc_asn1_list subject_pubkey[2];

   LTC_ARGCHK(in    != NULL);
   LTC_ARGCHK(inlen != 0);

   err = pk_get_oid(algorithm, &oid);
   if (err != CRYPT_OK) {
        return err;
   }

   /* see if the OpenSSL DER format RSA public key will work */
   tmpbuf = XCALLOC(1, MAX_RSA_SIZE*8);
   if (tmpbuf == NULL) {
       err = CRYPT_MEM;
       goto LBL_ERR;
   }

   /* this includes the internal hash ID and optional params (NULL in this case) */
   LTC_SET_ASN1(alg_id, 0, LTC_ASN1_OBJECT_IDENTIFIER, tmpoid, sizeof(tmpoid)/sizeof(tmpoid[0]));   
   LTC_SET_ASN1(alg_id, 1, parameters_type, parameters, parameters_len);

   /* the actual format of the SSL DER key is odd, it stores a RSAPublicKey in a **BIT** string ... so we have to extract it
      then proceed to convert bit to octet 
    */
   LTC_SET_ASN1(subject_pubkey, 0, LTC_ASN1_SEQUENCE, alg_id, 2);
   LTC_SET_ASN1(subject_pubkey, 1, LTC_ASN1_BIT_STRING, tmpbuf, MAX_RSA_SIZE*8);

   err=der_decode_sequence(in, inlen, subject_pubkey, 2UL);
   if (err != CRYPT_OK) {
           goto LBL_ERR;
   }

   len = subject_pubkey[1].size/8;
   if (*public_key_len > len) {
       memcpy(public_key, subject_pubkey[1].data, len);
       *public_key_len = len;
    } else {
        *public_key_len = len;
        err = CRYPT_BUFFER_OVERFLOW;
        goto LBL_ERR;
    }

    err = CRYPT_OK;
    
LBL_ERR:

    XFREE(tmpbuf);
        
    return err;
}

#endif