1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
|
/* $OpenBSD: mac.c,v 1.26 2014/01/04 17:50:55 tedu Exp $ */
/*
* Copyright (c) 2001 Markus Friedl. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "includes.h"
#include <sys/types.h>
#include <openssl/hmac.h>
#include <stdarg.h>
#include <string.h>
#include <signal.h>
#include "xmalloc.h"
#include "log.h"
#include "cipher.h"
#include "buffer.h"
#include "key.h"
#include "kex.h"
#include "mac.h"
#include "misc.h"
#include "umac.h"
#include "openbsd-compat/openssl-compat.h"
#define SSH_EVP 1 /* OpenSSL EVP-based MAC */
#define SSH_UMAC 2 /* UMAC (not integrated with OpenSSL) */
#define SSH_UMAC128 3
struct macalg {
char *name;
int type;
const EVP_MD * (*mdfunc)(void);
int truncatebits; /* truncate digest if != 0 */
int key_len; /* just for UMAC */
int len; /* just for UMAC */
int etm; /* Encrypt-then-MAC */
};
static const struct macalg macs[] = {
/* Encrypt-and-MAC (encrypt-and-authenticate) variants */
{ "hmac-sha1", SSH_EVP, EVP_sha1, 0, 0, 0, 0 },
{ "hmac-sha1-96", SSH_EVP, EVP_sha1, 96, 0, 0, 0 },
#ifdef HAVE_EVP_SHA256
{ "hmac-sha2-256", SSH_EVP, EVP_sha256, 0, 0, 0, 0 },
{ "hmac-sha2-512", SSH_EVP, EVP_sha512, 0, 0, 0, 0 },
#endif
{ "hmac-md5", SSH_EVP, EVP_md5, 0, 0, 0, 0 },
{ "hmac-md5-96", SSH_EVP, EVP_md5, 96, 0, 0, 0 },
{ "hmac-ripemd160", SSH_EVP, EVP_ripemd160, 0, 0, 0, 0 },
{ "hmac-ripemd160@openssh.com", SSH_EVP, EVP_ripemd160, 0, 0, 0, 0 },
{ "umac-64@openssh.com", SSH_UMAC, NULL, 0, 128, 64, 0 },
{ "umac-128@openssh.com", SSH_UMAC128, NULL, 0, 128, 128, 0 },
/* Encrypt-then-MAC variants */
{ "hmac-sha1-etm@openssh.com", SSH_EVP, EVP_sha1, 0, 0, 0, 1 },
{ "hmac-sha1-96-etm@openssh.com", SSH_EVP, EVP_sha1, 96, 0, 0, 1 },
#ifdef HAVE_EVP_SHA256
{ "hmac-sha2-256-etm@openssh.com", SSH_EVP, EVP_sha256, 0, 0, 0, 1 },
{ "hmac-sha2-512-etm@openssh.com", SSH_EVP, EVP_sha512, 0, 0, 0, 1 },
#endif
{ "hmac-md5-etm@openssh.com", SSH_EVP, EVP_md5, 0, 0, 0, 1 },
{ "hmac-md5-96-etm@openssh.com", SSH_EVP, EVP_md5, 96, 0, 0, 1 },
{ "hmac-ripemd160-etm@openssh.com", SSH_EVP, EVP_ripemd160, 0, 0, 0, 1 },
{ "umac-64-etm@openssh.com", SSH_UMAC, NULL, 0, 128, 64, 1 },
{ "umac-128-etm@openssh.com", SSH_UMAC128, NULL, 0, 128, 128, 1 },
{ NULL, 0, NULL, 0, 0, 0, 0 }
};
/* Returns a list of supported MACs separated by the specified char. */
char *
mac_alg_list(char sep)
{
char *ret = NULL;
size_t nlen, rlen = 0;
const struct macalg *m;
for (m = macs; m->name != NULL; m++) {
if (ret != NULL)
ret[rlen++] = sep;
nlen = strlen(m->name);
ret = xrealloc(ret, 1, rlen + nlen + 2);
memcpy(ret + rlen, m->name, nlen + 1);
rlen += nlen;
}
return ret;
}
static void
mac_setup_by_alg(Mac *mac, const struct macalg *macalg)
{
int evp_len;
mac->type = macalg->type;
if (mac->type == SSH_EVP) {
mac->evp_md = macalg->mdfunc();
if ((evp_len = EVP_MD_size(mac->evp_md)) <= 0)
fatal("mac %s len %d", mac->name, evp_len);
mac->key_len = mac->mac_len = (u_int)evp_len;
} else {
mac->mac_len = macalg->len / 8;
mac->key_len = macalg->key_len / 8;
mac->umac_ctx = NULL;
}
if (macalg->truncatebits != 0)
mac->mac_len = macalg->truncatebits / 8;
mac->etm = macalg->etm;
}
int
mac_setup(Mac *mac, char *name)
{
const struct macalg *m;
for (m = macs; m->name != NULL; m++) {
if (strcmp(name, m->name) != 0)
continue;
if (mac != NULL)
mac_setup_by_alg(mac, m);
debug2("mac_setup: found %s", name);
return (0);
}
debug2("mac_setup: unknown %s", name);
return (-1);
}
int
mac_init(Mac *mac)
{
if (mac->key == NULL)
fatal("mac_init: no key");
switch (mac->type) {
case SSH_EVP:
if (mac->evp_md == NULL)
return -1;
HMAC_CTX_init(&mac->evp_ctx);
HMAC_Init(&mac->evp_ctx, mac->key, mac->key_len, mac->evp_md);
return 0;
case SSH_UMAC:
mac->umac_ctx = umac_new(mac->key);
return 0;
case SSH_UMAC128:
mac->umac_ctx = umac128_new(mac->key);
return 0;
default:
return -1;
}
}
u_char *
mac_compute(Mac *mac, u_int32_t seqno, u_char *data, int datalen)
{
static union {
u_char m[EVP_MAX_MD_SIZE];
u_int64_t for_align;
} u;
u_char b[4], nonce[8];
if (mac->mac_len > sizeof(u))
fatal("mac_compute: mac too long %u %zu",
mac->mac_len, sizeof(u));
switch (mac->type) {
case SSH_EVP:
put_u32(b, seqno);
/* reset HMAC context */
HMAC_Init(&mac->evp_ctx, NULL, 0, NULL);
HMAC_Update(&mac->evp_ctx, b, sizeof(b));
HMAC_Update(&mac->evp_ctx, data, datalen);
HMAC_Final(&mac->evp_ctx, u.m, NULL);
break;
case SSH_UMAC:
put_u64(nonce, seqno);
umac_update(mac->umac_ctx, data, datalen);
umac_final(mac->umac_ctx, u.m, nonce);
break;
case SSH_UMAC128:
put_u64(nonce, seqno);
umac128_update(mac->umac_ctx, data, datalen);
umac128_final(mac->umac_ctx, u.m, nonce);
break;
default:
fatal("mac_compute: unknown MAC type");
}
return (u.m);
}
void
mac_clear(Mac *mac)
{
if (mac->type == SSH_UMAC) {
if (mac->umac_ctx != NULL)
umac_delete(mac->umac_ctx);
} else if (mac->type == SSH_UMAC128) {
if (mac->umac_ctx != NULL)
umac128_delete(mac->umac_ctx);
} else if (mac->evp_md != NULL)
HMAC_cleanup(&mac->evp_ctx);
mac->evp_md = NULL;
mac->umac_ctx = NULL;
}
/* XXX copied from ciphers_valid */
#define MAC_SEP ","
int
mac_valid(const char *names)
{
char *maclist, *cp, *p;
if (names == NULL || strcmp(names, "") == 0)
return (0);
maclist = cp = xstrdup(names);
for ((p = strsep(&cp, MAC_SEP)); p && *p != '\0';
(p = strsep(&cp, MAC_SEP))) {
if (mac_setup(NULL, p) < 0) {
debug("bad mac %s [%s]", p, names);
free(maclist);
return (0);
} else {
debug3("mac ok: %s [%s]", p, names);
}
}
debug3("macs ok: [%s]", names);
free(maclist);
return (1);
}
|
