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
36#ifdef KRB5
37#include <krb5-types.h>
38#endif
39
40#ifdef HAVE_COMMONCRYPTO_COMMONKEYDERIVATION_H
41#include <CommonCrypto/CommonKeyDerivation.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
68int
69PKCS5_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#ifdef HAVE_COMMONCRYPTO_COMMONKEYDERIVATION_H
75    if (CCKeyDerivationPBKDF(kCCPBKDF2, password, password_len,
76			     salt, salt_len,
77			     kCCPRFHmacAlgSHA1, iter,
78			     key, keylen) != 0)
79	return 0;
80    return 1;
81#else
82    size_t datalen, leftofkey, checksumsize;
83    char *data, *tmpcksum;
84    uint32_t keypart;
85    const EVP_MD *md;
86    unsigned long i;
87    int j;
88    char *p;
89    unsigned int hmacsize;
90
91    md = EVP_sha1();
92    checksumsize = EVP_MD_size(md);
93    datalen = salt_len + 4;
94
95    tmpcksum = malloc(checksumsize + datalen);
96    if (tmpcksum == NULL)
97	return 0;
98
99    data = &tmpcksum[checksumsize];
100
101    memcpy(data, salt, salt_len);
102
103    keypart = 1;
104    leftofkey = keylen;
105    p = key;
106
107    while (leftofkey) {
108	int len;
109
110	if (leftofkey > checksumsize)
111	    len = checksumsize;
112	else
113	    len = leftofkey;
114
115	data[datalen - 4] = (keypart >> 24) & 0xff;
116	data[datalen - 3] = (keypart >> 16) & 0xff;
117	data[datalen - 2] = (keypart >> 8)  & 0xff;
118	data[datalen - 1] = (keypart)       & 0xff;
119
120	HMAC(md, password, password_len, data, datalen,
121	     tmpcksum, &hmacsize);
122
123	memcpy(p, tmpcksum, len);
124	for (i = 1; i < iter; i++) {
125	    HMAC(md, password, password_len, tmpcksum, checksumsize,
126		 tmpcksum, &hmacsize);
127
128	    for (j = 0; j < len; j++)
129		p[j] ^= tmpcksum[j];
130	}
131
132	p += len;
133	leftofkey -= len;
134	keypart++;
135    }
136
137    free(tmpcksum);
138
139    return 1;
140#endif
141}
142