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