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: stable/11/sys/geom/eli/pkcs5v2.c 329175 2018-02-12 17:44:35Z kevans $");
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	struct hmac_ctx startpoint, ctx;
60
61	passlen = strlen(passphrase);
62	bzero(key, keylen);
63	bcopy(salt, saltcount, saltsize);
64	counter = saltcount + saltsize;
65
66	keyp = key;
67	for (count = 1; keylen > 0; count++, keylen -= bsize, keyp += bsize) {
68		bsize = MIN(keylen, sizeof(md));
69
70		be32enc(counter, count);
71
72		g_eli_crypto_hmac_init(&startpoint, passphrase, passlen);
73		ctx = startpoint;
74		g_eli_crypto_hmac_update(&ctx, saltcount, sizeof(saltcount));
75		g_eli_crypto_hmac_final(&ctx, md, sizeof(md));
76		xor(keyp, md, bsize);
77
78		for(i = 1; i < iterations; i++) {
79			ctx = startpoint;
80			g_eli_crypto_hmac_update(&ctx, md, sizeof(md));
81			g_eli_crypto_hmac_final(&ctx, md, sizeof(md));
82			xor(keyp, md, bsize);
83		}
84	}
85	explicit_bzero(&startpoint, sizeof(startpoint));
86	explicit_bzero(&ctx, sizeof(ctx));
87}
88
89#ifndef _KERNEL
90#ifndef _STANDALONE
91/*
92 * Return the number of microseconds needed for 'interations' iterations.
93 */
94static int
95pkcs5v2_probe(int iterations)
96{
97	uint8_t	key[G_ELI_USERKEYLEN], salt[G_ELI_SALTLEN];
98	uint8_t passphrase[] = "passphrase";
99	struct rusage start, end;
100	int usecs;
101
102	getrusage(RUSAGE_SELF, &start);
103	pkcs5v2_genkey(key, sizeof(key), salt, sizeof(salt), passphrase,
104	    iterations);
105	getrusage(RUSAGE_SELF, &end);
106
107	usecs = end.ru_utime.tv_sec - start.ru_utime.tv_sec;
108	usecs *= 1000000;
109	usecs += end.ru_utime.tv_usec - start.ru_utime.tv_usec;
110	return (usecs);
111}
112
113/*
114 * Return the number of iterations which takes 'usecs' microseconds.
115 */
116int
117pkcs5v2_calculate(int usecs)
118{
119	int iterations, v;
120
121	for (iterations = 1; ; iterations <<= 1) {
122		v = pkcs5v2_probe(iterations);
123		if (v > 2000000)
124			break;
125	}
126	return (((intmax_t)iterations * (intmax_t)usecs) / v);
127}
128#endif	/* !_STANDALONE */
129#endif	/* !_KERNEL */
130