1 /* $OpenBSD: mac.c,v 1.30 2014/04/30 19:07:48 naddy 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>
47 #include "openbsd-compat/openssl-compat.h"
49 #define SSH_DIGEST 1 /* SSH_DIGEST_XXX */
50 #define SSH_UMAC 2 /* UMAC (not integrated with OpenSSL) */
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 */
63 static const struct macalg macs
[] = {
64 /* Encrypt-and-MAC (encrypt-and-authenticate) variants */
65 { "hmac-sha1", SSH_DIGEST
, SSH_DIGEST_SHA1
, 0, 0, 0, 0 },
66 { "hmac-sha1-96", SSH_DIGEST
, SSH_DIGEST_SHA1
, 96, 0, 0, 0 },
67 #ifdef HAVE_EVP_SHA256
68 { "hmac-sha2-256", SSH_DIGEST
, SSH_DIGEST_SHA256
, 0, 0, 0, 0 },
69 { "hmac-sha2-512", SSH_DIGEST
, SSH_DIGEST_SHA512
, 0, 0, 0, 0 },
71 { "hmac-md5", SSH_DIGEST
, SSH_DIGEST_MD5
, 0, 0, 0, 0 },
72 { "hmac-md5-96", SSH_DIGEST
, SSH_DIGEST_MD5
, 96, 0, 0, 0 },
73 { "hmac-ripemd160", SSH_DIGEST
, SSH_DIGEST_RIPEMD160
, 0, 0, 0, 0 },
74 { "hmac-ripemd160@openssh.com", SSH_DIGEST
, SSH_DIGEST_RIPEMD160
, 0, 0, 0, 0 },
75 { "umac-64@openssh.com", SSH_UMAC
, 0, 0, 128, 64, 0 },
76 { "umac-128@openssh.com", SSH_UMAC128
, 0, 0, 128, 128, 0 },
78 /* Encrypt-then-MAC variants */
79 { "hmac-sha1-etm@openssh.com", SSH_DIGEST
, SSH_DIGEST_SHA1
, 0, 0, 0, 1 },
80 { "hmac-sha1-96-etm@openssh.com", SSH_DIGEST
, SSH_DIGEST_SHA1
, 96, 0, 0, 1 },
81 #ifdef HAVE_EVP_SHA256
82 { "hmac-sha2-256-etm@openssh.com", SSH_DIGEST
, SSH_DIGEST_SHA256
, 0, 0, 0, 1 },
83 { "hmac-sha2-512-etm@openssh.com", SSH_DIGEST
, SSH_DIGEST_SHA512
, 0, 0, 0, 1 },
85 { "hmac-md5-etm@openssh.com", SSH_DIGEST
, SSH_DIGEST_MD5
, 0, 0, 0, 1 },
86 { "hmac-md5-96-etm@openssh.com", SSH_DIGEST
, SSH_DIGEST_MD5
, 96, 0, 0, 1 },
87 { "hmac-ripemd160-etm@openssh.com", SSH_DIGEST
, SSH_DIGEST_RIPEMD160
, 0, 0, 0, 1 },
88 { "umac-64-etm@openssh.com", SSH_UMAC
, 0, 0, 128, 64, 1 },
89 { "umac-128-etm@openssh.com", SSH_UMAC128
, 0, 0, 128, 128, 1 },
91 { NULL
, 0, 0, 0, 0, 0, 0 }
94 /* Returns a list of supported MACs separated by the specified char. */
96 mac_alg_list(char sep
)
99 size_t nlen
, rlen
= 0;
100 const struct macalg
*m
;
102 for (m
= macs
; m
->name
!= NULL
; m
++) {
105 nlen
= strlen(m
->name
);
106 ret
= xrealloc(ret
, 1, rlen
+ nlen
+ 2);
107 memcpy(ret
+ rlen
, m
->name
, nlen
+ 1);
114 mac_setup_by_alg(Mac
*mac
, const struct macalg
*macalg
)
116 mac
->type
= macalg
->type
;
117 if (mac
->type
== SSH_DIGEST
) {
118 if ((mac
->hmac_ctx
= ssh_hmac_start(macalg
->alg
)) == NULL
)
119 fatal("ssh_hmac_start(alg=%d) failed", macalg
->alg
);
120 mac
->key_len
= mac
->mac_len
= ssh_hmac_bytes(macalg
->alg
);
122 mac
->mac_len
= macalg
->len
/ 8;
123 mac
->key_len
= macalg
->key_len
/ 8;
124 mac
->umac_ctx
= NULL
;
126 if (macalg
->truncatebits
!= 0)
127 mac
->mac_len
= macalg
->truncatebits
/ 8;
128 mac
->etm
= macalg
->etm
;
132 mac_setup(Mac
*mac
, char *name
)
134 const struct macalg
*m
;
136 for (m
= macs
; m
->name
!= NULL
; m
++) {
137 if (strcmp(name
, m
->name
) != 0)
140 mac_setup_by_alg(mac
, m
);
141 debug2("mac_setup: setup %s", name
);
145 debug2("mac_setup: unknown %s", name
);
152 if (mac
->key
== NULL
)
153 fatal("%s: no key", __func__
);
156 if (mac
->hmac_ctx
== NULL
||
157 ssh_hmac_init(mac
->hmac_ctx
, mac
->key
, mac
->key_len
) < 0)
161 mac
->umac_ctx
= umac_new(mac
->key
);
164 mac
->umac_ctx
= umac128_new(mac
->key
);
172 mac_compute(Mac
*mac
, u_int32_t seqno
, u_char
*data
, int datalen
)
175 u_char m
[EVP_MAX_MD_SIZE
];
181 if (mac
->mac_len
> sizeof(u
))
182 fatal("mac_compute: mac too long %u %zu",
183 mac
->mac_len
, sizeof(u
));
188 /* reset HMAC context */
189 if (ssh_hmac_init(mac
->hmac_ctx
, NULL
, 0) < 0 ||
190 ssh_hmac_update(mac
->hmac_ctx
, b
, sizeof(b
)) < 0 ||
191 ssh_hmac_update(mac
->hmac_ctx
, data
, datalen
) < 0 ||
192 ssh_hmac_final(mac
->hmac_ctx
, u
.m
, sizeof(u
.m
)) < 0)
193 fatal("ssh_hmac failed");
196 put_u64(nonce
, seqno
);
197 umac_update(mac
->umac_ctx
, data
, datalen
);
198 umac_final(mac
->umac_ctx
, u
.m
, nonce
);
201 put_u64(nonce
, seqno
);
202 umac128_update(mac
->umac_ctx
, data
, datalen
);
203 umac128_final(mac
->umac_ctx
, u
.m
, nonce
);
206 fatal("mac_compute: unknown MAC type");
214 if (mac
->type
== SSH_UMAC
) {
215 if (mac
->umac_ctx
!= NULL
)
216 umac_delete(mac
->umac_ctx
);
217 } else if (mac
->type
== SSH_UMAC128
) {
218 if (mac
->umac_ctx
!= NULL
)
219 umac128_delete(mac
->umac_ctx
);
220 } else if (mac
->hmac_ctx
!= NULL
)
221 ssh_hmac_free(mac
->hmac_ctx
);
222 mac
->hmac_ctx
= NULL
;
223 mac
->umac_ctx
= NULL
;
226 /* XXX copied from ciphers_valid */
229 mac_valid(const char *names
)
231 char *maclist
, *cp
, *p
;
233 if (names
== NULL
|| strcmp(names
, "") == 0)
235 maclist
= cp
= xstrdup(names
);
236 for ((p
= strsep(&cp
, MAC_SEP
)); p
&& *p
!= '\0';
237 (p
= strsep(&cp
, MAC_SEP
))) {
238 if (mac_setup(NULL
, p
) < 0) {
239 debug("bad mac %s [%s]", p
, names
);
244 debug3("macs ok: [%s]", names
);