1 /* $OpenBSD: mac.c,v 1.21 2012/12/11 22:51:45 sthen 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) */
56 const EVP_MD * (*mdfunc)(void);
57 int truncatebits; /* truncate digest if != 0 */
58 int key_len; /* just for UMAC */
59 int len; /* just for UMAC */
60 int etm; /* Encrypt-then-MAC */
62 /* Encrypt-and-MAC (encrypt-and-authenticate) variants */
63 { "hmac-sha1", SSH_EVP, EVP_sha1, 0, 0, 0, 0 },
64 { "hmac-sha1-96", SSH_EVP, EVP_sha1, 96, 0, 0, 0 },
65 #ifdef HAVE_EVP_SHA256
66 { "hmac-sha2-256", SSH_EVP, EVP_sha256, 0, 0, 0, 0 },
67 { "hmac-sha2-512", SSH_EVP, EVP_sha512, 0, 0, 0, 0 },
69 { "hmac-md5", SSH_EVP, EVP_md5, 0, 0, 0, 0 },
70 { "hmac-md5-96", SSH_EVP, EVP_md5, 96, 0, 0, 0 },
71 { "hmac-ripemd160", SSH_EVP, EVP_ripemd160, 0, 0, 0, 0 },
72 { "hmac-ripemd160@openssh.com", SSH_EVP, EVP_ripemd160, 0, 0, 0, 0 },
73 { "umac-64@openssh.com", SSH_UMAC, NULL, 0, 128, 64, 0 },
74 { "umac-128@openssh.com", SSH_UMAC128, NULL, 0, 128, 128, 0 },
76 /* Encrypt-then-MAC variants */
77 { "hmac-sha1-etm@openssh.com", SSH_EVP, EVP_sha1, 0, 0, 0, 1 },
78 { "hmac-sha1-96-etm@openssh.com", SSH_EVP, EVP_sha1, 96, 0, 0, 1 },
79 #ifdef HAVE_EVP_SHA256
80 { "hmac-sha2-256-etm@openssh.com", SSH_EVP, EVP_sha256, 0, 0, 0, 1 },
81 { "hmac-sha2-512-etm@openssh.com", SSH_EVP, EVP_sha512, 0, 0, 0, 1 },
83 { "hmac-md5-etm@openssh.com", SSH_EVP, EVP_md5, 0, 0, 0, 1 },
84 { "hmac-md5-96-etm@openssh.com", SSH_EVP, EVP_md5, 96, 0, 0, 1 },
85 { "hmac-ripemd160-etm@openssh.com", SSH_EVP, EVP_ripemd160, 0, 0, 0, 1 },
86 { "umac-64-etm@openssh.com", SSH_UMAC, NULL, 0, 128, 64, 1 },
87 { "umac-128-etm@openssh.com", SSH_UMAC128, NULL, 0, 128, 128, 1 },
89 { NULL, 0, NULL, 0, 0, 0, 0 }
93 mac_setup_by_id(Mac *mac, int which)
96 mac->type = macs[which].type;
97 if (mac->type == SSH_EVP) {
98 mac->evp_md = (*macs[which].mdfunc)();
99 if ((evp_len = EVP_MD_size(mac->evp_md)) <= 0)
100 fatal("mac %s len %d", mac->name, evp_len);
101 mac->key_len = mac->mac_len = (u_int)evp_len;
103 mac->mac_len = macs[which].len / 8;
104 mac->key_len = macs[which].key_len / 8;
105 mac->umac_ctx = NULL;
107 if (macs[which].truncatebits != 0)
108 mac->mac_len = macs[which].truncatebits / 8;
109 mac->etm = macs[which].etm;
113 mac_setup(Mac *mac, char *name)
117 for (i = 0; macs[i].name; i++) {
118 if (strcmp(name, macs[i].name) == 0) {
120 mac_setup_by_id(mac, i);
121 debug2("mac_setup: found %s", name);
125 debug2("mac_setup: unknown %s", name);
132 if (mac->key == NULL)
133 fatal("mac_init: no key");
136 if (mac->evp_md == NULL)
138 HMAC_CTX_init(&mac->evp_ctx);
139 HMAC_Init(&mac->evp_ctx, mac->key, mac->key_len, mac->evp_md);
142 mac->umac_ctx = umac_new(mac->key);
145 mac->umac_ctx = umac128_new(mac->key);
153 mac_compute(Mac *mac, u_int32_t seqno, u_char *data, int datalen)
155 static u_char m[EVP_MAX_MD_SIZE];
156 u_char b[4], nonce[8];
158 if (mac->mac_len > sizeof(m))
159 fatal("mac_compute: mac too long %u %lu",
160 mac->mac_len, (u_long)sizeof(m));
165 /* reset HMAC context */
166 HMAC_Init(&mac->evp_ctx, NULL, 0, NULL);
167 HMAC_Update(&mac->evp_ctx, b, sizeof(b));
168 HMAC_Update(&mac->evp_ctx, data, datalen);
169 HMAC_Final(&mac->evp_ctx, m, NULL);
172 put_u64(nonce, seqno);
173 umac_update(mac->umac_ctx, data, datalen);
174 umac_final(mac->umac_ctx, m, nonce);
177 put_u64(nonce, seqno);
178 umac128_update(mac->umac_ctx, data, datalen);
179 umac128_final(mac->umac_ctx, m, nonce);
182 fatal("mac_compute: unknown MAC type");
190 if (mac->type == SSH_UMAC) {
191 if (mac->umac_ctx != NULL)
192 umac_delete(mac->umac_ctx);
193 } else if (mac->type == SSH_UMAC128) {
194 if (mac->umac_ctx != NULL)
195 umac128_delete(mac->umac_ctx);
196 } else if (mac->evp_md != NULL)
197 HMAC_cleanup(&mac->evp_ctx);
199 mac->umac_ctx = NULL;
202 /* XXX copied from ciphers_valid */
205 mac_valid(const char *names)
207 char *maclist, *cp, *p;
209 if (names == NULL || strcmp(names, "") == 0)
211 maclist = cp = xstrdup(names);
212 for ((p = strsep(&cp, MAC_SEP)); p && *p != '\0';
213 (p = strsep(&cp, MAC_SEP))) {
214 if (mac_setup(NULL, p) < 0) {
215 debug("bad mac %s [%s]", p, names);
219 debug3("mac ok: %s [%s]", p, names);
222 debug3("macs ok: [%s]", names);