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 #include <config.h>
  35 #include <roken.h>
  36
  37 #ifdef KRB5
  38 #include <krb5-types.h>
  39 #endif
  40
  41 #include <evp.h>
  42 #include <hmac.h>
  43
  44 /**
  45  * As descriped in PKCS5, convert a password, salt, and iteration counter into a crypto key.
  46  *
  47  * @param password Password.
  48  * @param password_len Length of password.
  49  * @param salt Salt
  50  * @param salt_len Length of salt.
  51  * @param iter iteration counter.
  52  * @param md the digest function.
  53  * @param keylen the output key length.
  54  * @param key the output key.
  55  *
  56  * @return 1 on success, non 1 on failure.
  57  *
  58  * @ingroup hcrypto_misc
  59  */
  60
  61 int
  62 PKCS5_PBKDF2_HMAC(const void * password, size_t password_len,
  63                   const void * salt, size_t salt_len,
  64                   unsigned long iter,
  65                   const EVP_MD *md,
  66                   size_t keylen, void *key)
  67 {
  68     size_t datalen, leftofkey, checksumsize;
  69     char *data, *tmpcksum;
  70     uint32_t keypart;
  71     unsigned long i;
  72     int j;
  73     char *p;
  74     unsigned int hmacsize;
  75
  76     if (md == NULL)
  77         return 0;
  78
  79     checksumsize = EVP_MD_size(md);
  80     datalen = salt_len + 4;
  81
  82     tmpcksum = malloc(checksumsize + datalen);
  83     if (tmpcksum == NULL)
  84         return 0;
  85
  86     data = &tmpcksum[checksumsize];
  87
  88     memcpy(data, salt, salt_len);
  89
  90     keypart = 1;
  91     leftofkey = keylen;
  92     p = key;
  93
  94     while (leftofkey) {
  95         int len;
  96
  97         if (leftofkey > checksumsize)
  98             len = checksumsize;
  99         else
 100             len = leftofkey;
 101
 102         data[datalen - 4] = (keypart >> 24) & 0xff;
 103         data[datalen - 3] = (keypart >> 16) & 0xff;
 104         data[datalen - 2] = (keypart >> 8)  & 0xff;
 105         data[datalen - 1] = (keypart)       & 0xff;
 106
 107         HMAC(md, password, password_len, data, datalen,
 108              tmpcksum, &hmacsize);
 109
 110         memcpy(p, tmpcksum, len);
 111         for (i = 1; i < iter; i++) {
 112             HMAC(md, password, password_len, tmpcksum, checksumsize,
 113                  tmpcksum, &hmacsize);
 114
 115             for (j = 0; j < len; j++)
 116                 p[j] ^= tmpcksum[j];
 117         }
 118
 119         p += len;
 120         leftofkey -= len;
 121         keypart++;
 122     }
 123
 124     free(tmpcksum);
 125
 126     return 1;
 127 }
 128
 129 /**
 130  * As descriped in PKCS5, convert a password, salt, and iteration counter into a crypto key.
 131  *
 132  * @param password Password.
 133  * @param password_len Length of password.
 134  * @param salt Salt
 135  * @param salt_len Length of salt.
 136  * @param iter iteration counter.
 137  * @param keylen the output key length.
 138  * @param key the output key.
 139  *
 140  * @return 1 on success, non 1 on failure.
 141  *
 142  * @ingroup hcrypto_misc
 143  */
 144 int
 145 PKCS5_PBKDF2_HMAC_SHA1(const void * password, size_t password_len,
 146                        const void * salt, size_t salt_len,
 147                        unsigned long iter,
 148                        size_t keylen, void *key)
 149 {
 150     return PKCS5_PBKDF2_HMAC(password, password_len, salt, salt_len, iter,
 151                              EVP_sha1(), keylen, key);
 152 }