/*

 * Copyright (c) 2006 Kungliga Tekniska Högskolan

 * (Royal Institute of Technology, Stockholm, Sweden).

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 *

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 *

 * 3. Neither the name of the Institute nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND

 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE

 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 */

#include <config.h>

#include <roken.h>

#ifdef KRB5

#include <krb5-types.h>

#endif

#include <evp.h>

#include <hmac.h>

/**

 * As descriped in PKCS5, convert a password, salt, and iteration counter into a crypto key.

 *

 * @param password Password.

 * @param password_len Length of password.

 * @param salt Salt

 * @param salt_len Length of salt.

 * @param iter iteration counter.

 * @param md the digest function.

 * @param keylen the output key length.

 * @param key the output key.

 *

 * @return 1 on success, non 1 on failure.

 *

 * @ingroup hcrypto_misc

 */

int

PKCS5_PBKDF2_HMAC(const void * password, size_t password_len,

      const void * salt, size_t salt_len,

      unsigned long iter,

      const EVP_MD *md,

      size_t keylen, void *key)

{

    size_t datalen, leftofkey, checksumsize;

    char *data, *tmpcksum;

    uint32_t keypart;

    unsigned long i;

    int j;

    char *p;

    unsigned int hmacsize;

    if (md == NULL)

  return 0;

    checksumsize = EVP_MD_size(md);

    datalen = salt_len + 4;

    tmpcksum = malloc(checksumsize + datalen);

    if (tmpcksum == NULL)

  return 0;

    data = &tmpcksum[checksumsize];

    if (salt_len)

        memcpy(data, salt, salt_len);

    keypart = 1;

    leftofkey = keylen;

    p = key;

    while (leftofkey) {

  int len;

  if (leftofkey > checksumsize)

      len = checksumsize;

  else

      len = leftofkey;

  data[datalen - 4] = (keypart >> 24) & 0xff;

  data[datalen - 3] = (keypart >> 16) & 0xff;

  data[datalen - 2] = (keypart >> 8)  & 0xff;

  data[datalen - 1] = (keypart)       & 0xff;

  HMAC(md, password, password_len, data, datalen,

       tmpcksum, &hmacsize);

  memcpy(p, tmpcksum, len);

  for (i = 1; i < iter; i++) {

      HMAC(md, password, password_len, tmpcksum, checksumsize,

     tmpcksum, &hmacsize);

      for (j = 0; j < len; j++)

    p[j] ^= tmpcksum[j];

  }

  p += len;

  leftofkey -= len;

  keypart++;

    }

    free(tmpcksum);

    return 1;

}

/**

 * As descriped in PKCS5, convert a password, salt, and iteration counter into a crypto key.

 *

 * @param password Password.

 * @param password_len Length of password.

 * @param salt Salt

 * @param salt_len Length of salt.

 * @param iter iteration counter.

 * @param keylen the output key length.

 * @param key the output key.

 *

 * @return 1 on success, non 1 on failure.

 *

 * @ingroup hcrypto_misc

 */

int

PKCS5_PBKDF2_HMAC_SHA1(const void * password, size_t password_len,

           const void * salt, size_t salt_len,

           unsigned long iter,

           size_t keylen, void *key)

{

    return PKCS5_PBKDF2_HMAC(password, password_len, salt, salt_len, iter,

           EVP_sha1(), keylen, key);

}