lib/hcrypto/pkcs5.c

   1 /*
   2  * Copyright (c) 2006 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #ifdef HAVE_CONFIG_H
  35 #include <config.h>
  36 #endif
  37
  38 RCSID("$Id$");
  39
  40 #ifdef KRB5
  41 #include <krb5-types.h>
  42 #endif
  43
  44 #include <stdio.h>
  45 #include <stdlib.h>
  46
  47 #include <evp.h>
  48 #include <hmac.h>
  49
  50 #include <roken.h>
  51
  52 /**
  53  * As descriped in PKCS5, convert a password, salt, and iteration counter into a crypto key.
  54  *
  55  * @param password Password.
  56  * @param password_len Length of password.
  57  * @param salt Salt
  58  * @param salt_len Length of salt.
  59  * @param iter iteration counter.
  60  * @param keylen the output key length.
  61  * @param key the output key.
  62  *
  63  * @return 1 on success, non 1 on failure.
  64  *
  65  * @ingroup hcrypto_misc
  66  */
  67
  68 int
  69 PKCS5_PBKDF2_HMAC_SHA1(const void * password, size_t password_len,
  70                        const void * salt, size_t salt_len,
  71                        unsigned long iter,
  72                        size_t keylen, void *key)
  73 {
  74     size_t datalen, leftofkey, checksumsize;
  75     char *data, *tmpcksum;
  76     uint32_t keypart;
  77     const EVP_MD *md;
  78     unsigned long i;
  79     int j;
  80     char *p;
  81     unsigned int hmacsize;
  82
  83     md = EVP_sha1();
  84     checksumsize = EVP_MD_size(md);
  85     datalen = salt_len + 4;
  86
  87     tmpcksum = malloc(checksumsize + datalen);
  88     if (tmpcksum == NULL)
  89         return 0;
  90
  91     data = &tmpcksum[checksumsize];
  92
  93     memcpy(data, salt, salt_len);
  94
  95     keypart = 1;
  96     leftofkey = keylen;
  97     p = key;
  98
  99     while (leftofkey) {
 100         int len;
 101
 102         if (leftofkey > checksumsize)
 103             len = checksumsize;
 104         else
 105             len = leftofkey;
 106
 107         data[datalen - 4] = (keypart >> 24) & 0xff;
 108         data[datalen - 3] = (keypart >> 16) & 0xff;
 109         data[datalen - 2] = (keypart >> 8)  & 0xff;
 110         data[datalen - 1] = (keypart)       & 0xff;
 111
 112         HMAC(md, password, password_len, data, datalen,
 113              tmpcksum, &hmacsize);
 114
 115         memcpy(p, tmpcksum, len);
 116         for (i = 1; i < iter; i++) {
 117             HMAC(md, password, password_len, tmpcksum, checksumsize,
 118                  tmpcksum, &hmacsize);
 119
 120             for (j = 0; j < len; j++)
 121                 p[j] ^= tmpcksum[j];
 122         }
 123
 124         p += len;
 125         leftofkey -= len;
 126         keypart++;
 127     }
 128
 129     free(tmpcksum);
 130
 131     return 1;
 132 }