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