xref: /freebsd/sys/geom/eli/g_eli_hmac.c (revision 4f52dfbb)
1 /*-
2  * Copyright (c) 2005-2010 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 #include <sys/malloc.h>
35 #elif defined(_STANDALONE)
36 #include "stand.h"
37 #else
38 #include <stdint.h>
39 #include <string.h>
40 #include <strings.h>
41 #include <errno.h>
42 #include <assert.h>
43 #include <openssl/evp.h>
44 #define	_OpenSSL_
45 #endif
46 #include <geom/eli/g_eli.h>
47 
48 void
49 g_eli_crypto_hmac_init(struct hmac_ctx *ctx, const uint8_t *hkey,
50     size_t hkeylen)
51 {
52 	u_char k_ipad[128], k_opad[128], key[128];
53 	SHA512_CTX lctx;
54 	u_int i;
55 
56 	bzero(key, sizeof(key));
57 	if (hkeylen == 0)
58 		; /* do nothing */
59 	else if (hkeylen <= 128)
60 		bcopy(hkey, key, hkeylen);
61 	else {
62 		/* If key is longer than 128 bytes reset it to key = SHA512(key). */
63 		SHA512_Init(&lctx);
64 		SHA512_Update(&lctx, hkey, hkeylen);
65 		SHA512_Final(key, &lctx);
66 	}
67 
68 	/* XOR key with ipad and opad values. */
69 	for (i = 0; i < sizeof(key); i++) {
70 		k_ipad[i] = key[i] ^ 0x36;
71 		k_opad[i] = key[i] ^ 0x5c;
72 	}
73 	explicit_bzero(key, sizeof(key));
74 	/* Start inner SHA512. */
75 	SHA512_Init(&ctx->innerctx);
76 	SHA512_Update(&ctx->innerctx, k_ipad, sizeof(k_ipad));
77 	explicit_bzero(k_ipad, sizeof(k_ipad));
78 	/* Start outer SHA512. */
79 	SHA512_Init(&ctx->outerctx);
80 	SHA512_Update(&ctx->outerctx, k_opad, sizeof(k_opad));
81 	explicit_bzero(k_opad, sizeof(k_opad));
82 }
83 
84 void
85 g_eli_crypto_hmac_update(struct hmac_ctx *ctx, const uint8_t *data,
86     size_t datasize)
87 {
88 
89 	SHA512_Update(&ctx->innerctx, data, datasize);
90 }
91 
92 void
93 g_eli_crypto_hmac_final(struct hmac_ctx *ctx, uint8_t *md, size_t mdsize)
94 {
95 	u_char digest[SHA512_MDLEN];
96 
97 	/* Complete inner hash */
98 	SHA512_Final(digest, &ctx->innerctx);
99 
100 	/* Complete outer hash */
101 	SHA512_Update(&ctx->outerctx, digest, sizeof(digest));
102 	SHA512_Final(digest, &ctx->outerctx);
103 
104 	explicit_bzero(ctx, sizeof(*ctx));
105 	/* mdsize == 0 means "Give me the whole hash!" */
106 	if (mdsize == 0)
107 		mdsize = SHA512_MDLEN;
108 	bcopy(digest, md, mdsize);
109 	explicit_bzero(digest, sizeof(digest));
110 }
111 
112 void
113 g_eli_crypto_hmac(const uint8_t *hkey, size_t hkeysize, const uint8_t *data,
114     size_t datasize, uint8_t *md, size_t mdsize)
115 {
116 	struct hmac_ctx ctx;
117 
118 	g_eli_crypto_hmac_init(&ctx, hkey, hkeysize);
119 	g_eli_crypto_hmac_update(&ctx, data, datasize);
120 	g_eli_crypto_hmac_final(&ctx, md, mdsize);
121 }
122 
123 /*
124  * Here we generate IV. It is unique for every sector.
125  */
126 void
127 g_eli_crypto_ivgen(struct g_eli_softc *sc, off_t offset, u_char *iv,
128     size_t size)
129 {
130 	uint8_t off[8];
131 
132 	if ((sc->sc_flags & G_ELI_FLAG_NATIVE_BYTE_ORDER) != 0)
133 		bcopy(&offset, off, sizeof(off));
134 	else
135 		le64enc(off, (uint64_t)offset);
136 
137 	switch (sc->sc_ealgo) {
138 	case CRYPTO_AES_XTS:
139 		bcopy(off, iv, sizeof(off));
140 		bzero(iv + sizeof(off), size - sizeof(off));
141 		break;
142 	default:
143 	    {
144 		u_char hash[SHA256_DIGEST_LENGTH];
145 		SHA256_CTX ctx;
146 
147 		/* Copy precalculated SHA256 context for IV-Key. */
148 		bcopy(&sc->sc_ivctx, &ctx, sizeof(ctx));
149 		SHA256_Update(&ctx, off, sizeof(off));
150 		SHA256_Final(hash, &ctx);
151 		bcopy(hash, iv, MIN(sizeof(hash), size));
152 		break;
153 	    }
154 	}
155 }
156