gmac.c revision 302408 
1/*-
2 * Copyright (c) 2014 The FreeBSD Foundation
3 * All rights reserved.
4 *
5 * This software was developed by John-Mark Gurney under
6 * the sponsorship of the FreeBSD Foundation and
7 * Rubicon Communications, LLC (Netgate).
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1.  Redistributions of source code must retain the above copyright
12 *     notice, this list of conditions and the following disclaimer.
13 * 2.  Redistributions in binary form must reproduce the above copyright
14 *     notice, this list of conditions and the following disclaimer in the
15 *     documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 *	$FreeBSD: stable/11/sys/opencrypto/gmac.c 275732 2014-12-12 19:56:36Z jmg $
30 *
31 */
32
33#include <sys/types.h>
34#include <sys/systm.h>
35#include <opencrypto/gfmult.h>
36#include <opencrypto/gmac.h>
37
38void
39AES_GMAC_Init(struct aes_gmac_ctx *agc)
40{
41
42	bzero(agc, sizeof *agc);
43}
44
45void
46AES_GMAC_Setkey(struct aes_gmac_ctx *agc, const uint8_t *key, uint16_t klen)
47{
48	const uint8_t zeros[GMAC_BLOCK_LEN] = {};
49	struct gf128 h;
50	uint8_t hbuf[GMAC_BLOCK_LEN];
51
52	agc->rounds = rijndaelKeySetupEnc(agc->keysched, key, klen * 8);
53
54	rijndaelEncrypt(agc->keysched, agc->rounds, zeros, hbuf);
55
56	h = gf128_read(hbuf);
57	gf128_genmultable4(h, &agc->ghashtbl);
58
59	explicit_bzero(&h, sizeof h);
60	explicit_bzero(hbuf, sizeof hbuf);
61}
62
63void
64AES_GMAC_Reinit(struct aes_gmac_ctx *agc, const uint8_t *iv, uint16_t ivlen)
65{
66
67	KASSERT(ivlen <= sizeof agc->counter, ("passed ivlen too large!"));
68	bcopy(iv, agc->counter, ivlen);
69}
70
71int
72AES_GMAC_Update(struct aes_gmac_ctx *agc, const uint8_t *data, uint16_t len)
73{
74	struct gf128 v;
75	uint8_t buf[GMAC_BLOCK_LEN] = {};
76	int i;
77
78	v = agc->hash;
79
80	while (len > 0) {
81		if (len >= 4*GMAC_BLOCK_LEN) {
82			i = 4*GMAC_BLOCK_LEN;
83			v = gf128_mul4b(v, data, &agc->ghashtbl);
84		} else if (len >= GMAC_BLOCK_LEN) {
85			i = GMAC_BLOCK_LEN;
86			v = gf128_add(v, gf128_read(data));
87			v = gf128_mul(v, &agc->ghashtbl.tbls[0]);
88		} else {
89			i = len;
90			bcopy(data, buf, i);
91			v = gf128_add(v, gf128_read(&buf[0]));
92			v = gf128_mul(v, &agc->ghashtbl.tbls[0]);
93			explicit_bzero(buf, sizeof buf);
94		}
95		len -= i;
96		data += i;
97	}
98
99	agc->hash = v;
100	explicit_bzero(&v, sizeof v);
101
102	return (0);
103}
104
105void
106AES_GMAC_Final(uint8_t digest[GMAC_DIGEST_LEN], struct aes_gmac_ctx *agc)
107{
108	uint8_t enccntr[GMAC_BLOCK_LEN];
109	struct gf128 a;
110
111	/* XXX - zero additional bytes? */
112	agc->counter[GMAC_BLOCK_LEN - 1] = 1;
113
114	rijndaelEncrypt(agc->keysched, agc->rounds, agc->counter, enccntr);
115	a = gf128_add(agc->hash, gf128_read(enccntr));
116	gf128_write(a, digest);
117
118	explicit_bzero(enccntr, sizeof enccntr);
119}
120