1/* $NetBSD: aesxcbcmac.c,v 1.3 2020/06/29 23:34:48 riastradh Exp $ */
2
3/*
4 * Copyright (C) 1995, 1996, 1997, 1998 and 2003 WIDE Project.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the project nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#include <sys/cdefs.h>
33__KERNEL_RCSID(0, "$NetBSD: aesxcbcmac.c,v 1.3 2020/06/29 23:34:48 riastradh Exp $");
34
35#include <sys/param.h>
36#include <sys/systm.h>
37
38#include <crypto/aes/aes.h>
39
40#include <opencrypto/aesxcbcmac.h>
41
42int
43aes_xcbc_mac_init(void *vctx, const uint8_t *key, u_int16_t keylen)
44{
45	static const uint8_t k1seed[AES_BLOCKSIZE] =
46	    { 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1 };
47	static const uint8_t k2seed[AES_BLOCKSIZE] =
48	    { 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2 };
49	static const uint8_t k3seed[AES_BLOCKSIZE] =
50	    { 3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3 };
51	struct aesenc r_ks;
52	aesxcbc_ctx *ctx;
53	uint8_t k1[AES_BLOCKSIZE];
54
55	ctx = vctx;
56	memset(ctx, 0, sizeof(*ctx));
57
58	switch (keylen) {
59	case 16:
60		ctx->r_nr = aes_setenckey128(&r_ks, key);
61		break;
62	case 24:
63		ctx->r_nr = aes_setenckey192(&r_ks, key);
64		break;
65	case 32:
66		ctx->r_nr = aes_setenckey256(&r_ks, key);
67		break;
68	}
69	aes_enc(&r_ks, k1seed, k1, ctx->r_nr);
70	aes_enc(&r_ks, k2seed, ctx->k2, ctx->r_nr);
71	aes_enc(&r_ks, k3seed, ctx->k3, ctx->r_nr);
72	aes_setenckey128(&ctx->r_k1s, k1);
73
74	explicit_memset(&r_ks, 0, sizeof(r_ks));
75	explicit_memset(k1, 0, sizeof(k1));
76
77	return 0;
78}
79
80int
81aes_xcbc_mac_loop(void *vctx, const uint8_t *addr, u_int16_t len)
82{
83	uint8_t buf[AES_BLOCKSIZE];
84	aesxcbc_ctx *ctx;
85	const uint8_t *ep;
86	int i;
87
88	ctx = vctx;
89	ep = addr + len;
90
91	if (ctx->buflen == sizeof(ctx->buf)) {
92		for (i = 0; i < sizeof(ctx->e); i++)
93			ctx->buf[i] ^= ctx->e[i];
94		aes_enc(&ctx->r_k1s, ctx->buf, ctx->e, ctx->r_nr);
95		ctx->buflen = 0;
96	}
97	if (ctx->buflen + len < sizeof(ctx->buf)) {
98		memcpy(ctx->buf + ctx->buflen, addr, len);
99		ctx->buflen += len;
100		return 0;
101	}
102	if (ctx->buflen && ctx->buflen + len > sizeof(ctx->buf)) {
103		memcpy(ctx->buf + ctx->buflen, addr,
104		    sizeof(ctx->buf) - ctx->buflen);
105		for (i = 0; i < sizeof(ctx->e); i++)
106			ctx->buf[i] ^= ctx->e[i];
107		aes_enc(&ctx->r_k1s, ctx->buf, ctx->e, ctx->r_nr);
108		addr += sizeof(ctx->buf) - ctx->buflen;
109		ctx->buflen = 0;
110	}
111	/* due to the special processing for M[n], "=" case is not included */
112	while (ep - addr > AES_BLOCKSIZE) {
113		memcpy(buf, addr, AES_BLOCKSIZE);
114		for (i = 0; i < sizeof(buf); i++)
115			buf[i] ^= ctx->e[i];
116		aes_enc(&ctx->r_k1s, buf, ctx->e, ctx->r_nr);
117		addr += AES_BLOCKSIZE;
118	}
119	if (addr < ep) {
120		memcpy(ctx->buf + ctx->buflen, addr, ep - addr);
121		ctx->buflen += ep - addr;
122	}
123	return 0;
124}
125
126void
127aes_xcbc_mac_result(uint8_t *addr, void *vctx)
128{
129	uint8_t digest[AES_BLOCKSIZE];
130	aesxcbc_ctx *ctx;
131	int i;
132
133	ctx = vctx;
134
135	if (ctx->buflen == sizeof(ctx->buf)) {
136		for (i = 0; i < sizeof(ctx->buf); i++) {
137			ctx->buf[i] ^= ctx->e[i];
138			ctx->buf[i] ^= ctx->k2[i];
139		}
140		aes_enc(&ctx->r_k1s, ctx->buf, digest, ctx->r_nr);
141	} else {
142		for (i = ctx->buflen; i < sizeof(ctx->buf); i++)
143			ctx->buf[i] = (i == ctx->buflen) ? 0x80 : 0x00;
144		for (i = 0; i < sizeof(ctx->buf); i++) {
145			ctx->buf[i] ^= ctx->e[i];
146			ctx->buf[i] ^= ctx->k3[i];
147		}
148		aes_enc(&ctx->r_k1s, ctx->buf, digest, ctx->r_nr);
149	}
150
151	memcpy(addr, digest, sizeof(digest));
152}
153