xref: /freebsd/sys/geom/eli/pkcs5v2.c (revision 076ad2f836d5f49dc1375f1677335a48fe0d4b82)
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 
43 static __inline void
44 xor(uint8_t *dst, const uint8_t *src, size_t size)
45 {
46 
47 	for (; size > 0; size--)
48 		*dst++ ^= *src++;
49 }
50 
51 void
52 pkcs5v2_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 _STAND
91 /*
92  * Return the number of microseconds needed for 'interations' iterations.
93  */
94 static int
95 pkcs5v2_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  */
116 int
117 pkcs5v2_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	/* !_STAND */
129 #endif	/* !_KERNEL */
130