1/*-
2 * Copyright (c) 2005 Pawel Jakub Dawidek <pjd@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD$");
29
30#include <sys/param.h>
31#ifdef _KERNEL
32#include <sys/systm.h>
33#include <sys/kernel.h>
34#else
35#include <sys/resource.h>
36#include <stdint.h>
37#include <strings.h>
38#endif
39
40#include <geom/eli/g_eli.h>
41#include <geom/eli/pkcs5v2.h>
42
43static __inline void
44xor(uint8_t *dst, const uint8_t *src, size_t size)
45{
46
47	for (; size > 0; size--)
48		*dst++ ^= *src++;
49}
50
51void
52pkcs5v2_genkey(uint8_t *key, unsigned keylen, const uint8_t *salt,
53    size_t saltsize, const char *passphrase, u_int iterations)
54{
55	uint8_t md[SHA512_MDLEN], saltcount[saltsize + sizeof(uint32_t)];
56	uint8_t *counter, *keyp;
57	u_int i, bsize, passlen;
58	uint32_t count;
59
60	passlen = strlen(passphrase);
61	bzero(key, keylen);
62	bcopy(salt, saltcount, saltsize);
63	counter = saltcount + saltsize;
64
65	keyp = key;
66	for (count = 1; keylen > 0; count++, keylen -= bsize, keyp += bsize) {
67		bsize = MIN(keylen, sizeof(md));
68
69		counter[0] = (count >> 24) & 0xff;
70		counter[1] = (count >> 16) & 0xff;
71		counter[2] = (count >> 8) & 0xff;
72		counter[3] = count & 0xff;
73		g_eli_crypto_hmac(passphrase, passlen, saltcount,
74		    sizeof(saltcount), md, 0);
75		xor(keyp, md, bsize);
76
77		for(i = 1; i < iterations; i++) {
78			g_eli_crypto_hmac(passphrase, passlen, md, sizeof(md),
79			    md, 0);
80			xor(keyp, md, bsize);
81		}
82	}
83}
84
85#ifndef _KERNEL
86/*
87 * Return the number of microseconds needed for 'interations' iterations.
88 */
89static int
90pkcs5v2_probe(int iterations)
91{
92	uint8_t	key[G_ELI_USERKEYLEN], salt[G_ELI_SALTLEN];
93	uint8_t passphrase[] = "passphrase";
94	struct rusage start, end;
95	int usecs;
96
97	getrusage(RUSAGE_SELF, &start);
98	pkcs5v2_genkey(key, sizeof(key), salt, sizeof(salt), passphrase,
99	    iterations);
100	getrusage(RUSAGE_SELF, &end);
101
102	usecs = end.ru_utime.tv_sec - start.ru_utime.tv_sec;
103	usecs *= 1000000;
104	usecs += end.ru_utime.tv_usec - start.ru_utime.tv_usec;
105	return (usecs);
106}
107
108/*
109 * Return the number of iterations which takes 'usecs' microseconds.
110 */
111int
112pkcs5v2_calculate(int usecs)
113{
114	int iterations, v;
115
116	for (iterations = 1; ; iterations <<= 1) {
117		v = pkcs5v2_probe(iterations);
118		if (v > 2000000)
119			break;
120	}
121	return (((intmax_t)iterations * (intmax_t)usecs) / v);
122}
123#endif	/* !_KERNEL */
124