1 /* $OpenBSD: mac.c,v 1.18 2012/06/28 05:07:45 dtucker Exp $ */
3 * Copyright (c) 2001 Markus Friedl. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 #include <sys/types.h>
30 #include <openssl/hmac.h>
47 #include "openbsd-compat/openssl-compat.h"
49 #define SSH_EVP 1 /* OpenSSL EVP-based MAC */
50 #define SSH_UMAC 2 /* UMAC (not integrated with OpenSSL) */
55 const EVP_MD * (*mdfunc)(void);
56 int truncatebits; /* truncate digest if != 0 */
57 int key_len; /* just for UMAC */
58 int len; /* just for UMAC */
60 { "hmac-sha1", SSH_EVP, EVP_sha1, 0, -1, -1 },
61 { "hmac-sha1-96", SSH_EVP, EVP_sha1, 96, -1, -1 },
62 #ifdef HAVE_EVP_SHA256
63 { "hmac-sha2-256", SSH_EVP, EVP_sha256, 0, -1, -1 },
64 { "hmac-sha2-512", SSH_EVP, EVP_sha512, 0, -1, -1 },
66 { "hmac-md5", SSH_EVP, EVP_md5, 0, -1, -1 },
67 { "hmac-md5-96", SSH_EVP, EVP_md5, 96, -1, -1 },
68 { "hmac-ripemd160", SSH_EVP, EVP_ripemd160, 0, -1, -1 },
69 { "hmac-ripemd160@openssh.com", SSH_EVP, EVP_ripemd160, 0, -1, -1 },
70 { "umac-64@openssh.com", SSH_UMAC, NULL, 0, 128, 64 },
71 { NULL, 0, NULL, 0, -1, -1 }
75 mac_setup_by_id(Mac *mac, int which)
78 mac->type = macs[which].type;
79 if (mac->type == SSH_EVP) {
80 mac->evp_md = (*macs[which].mdfunc)();
81 if ((evp_len = EVP_MD_size(mac->evp_md)) <= 0)
82 fatal("mac %s len %d", mac->name, evp_len);
83 mac->key_len = mac->mac_len = (u_int)evp_len;
85 mac->mac_len = macs[which].len / 8;
86 mac->key_len = macs[which].key_len / 8;
89 if (macs[which].truncatebits != 0)
90 mac->mac_len = macs[which].truncatebits / 8;
94 mac_setup(Mac *mac, char *name)
98 for (i = 0; macs[i].name; i++) {
99 if (strcmp(name, macs[i].name) == 0) {
101 mac_setup_by_id(mac, i);
102 debug2("mac_setup: found %s", name);
106 debug2("mac_setup: unknown %s", name);
113 if (mac->key == NULL)
114 fatal("mac_init: no key");
117 if (mac->evp_md == NULL)
119 HMAC_CTX_init(&mac->evp_ctx);
120 HMAC_Init(&mac->evp_ctx, mac->key, mac->key_len, mac->evp_md);
123 mac->umac_ctx = umac_new(mac->key);
131 mac_compute(Mac *mac, u_int32_t seqno, u_char *data, int datalen)
133 static u_char m[EVP_MAX_MD_SIZE];
134 u_char b[4], nonce[8];
136 if (mac->mac_len > sizeof(m))
137 fatal("mac_compute: mac too long %u %lu",
138 mac->mac_len, (u_long)sizeof(m));
143 /* reset HMAC context */
144 HMAC_Init(&mac->evp_ctx, NULL, 0, NULL);
145 HMAC_Update(&mac->evp_ctx, b, sizeof(b));
146 HMAC_Update(&mac->evp_ctx, data, datalen);
147 HMAC_Final(&mac->evp_ctx, m, NULL);
150 put_u64(nonce, seqno);
151 umac_update(mac->umac_ctx, data, datalen);
152 umac_final(mac->umac_ctx, m, nonce);
155 fatal("mac_compute: unknown MAC type");
163 if (mac->type == SSH_UMAC) {
164 if (mac->umac_ctx != NULL)
165 umac_delete(mac->umac_ctx);
166 } else if (mac->evp_md != NULL)
167 HMAC_cleanup(&mac->evp_ctx);
169 mac->umac_ctx = NULL;
172 /* XXX copied from ciphers_valid */
175 mac_valid(const char *names)
177 char *maclist, *cp, *p;
179 if (names == NULL || strcmp(names, "") == 0)
181 maclist = cp = xstrdup(names);
182 for ((p = strsep(&cp, MAC_SEP)); p && *p != '\0';
183 (p = strsep(&cp, MAC_SEP))) {
184 if (mac_setup(NULL, p) < 0) {
185 debug("bad mac %s [%s]", p, names);
189 debug3("mac ok: %s [%s]", p, names);
192 debug3("macs ok: [%s]", names);