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Damien Miller74f13bd2012-12-12 10:46:53 +11001/* $OpenBSD: mac.c,v 1.21 2012/12/11 22:51:45 sthen Exp $ */
Ben Lindstrom06b33aa2001-02-15 03:01:59 +00002/*
3 * Copyright (c) 2001 Markus Friedl. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
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.
13 *
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.
24 */
25
26#include "includes.h"
Ben Lindstrom06b33aa2001-02-15 03:01:59 +000027
Damien Millerd7834352006-08-05 12:39:39 +100028#include <sys/types.h>
29
Ben Lindstrom06b33aa2001-02-15 03:01:59 +000030#include <openssl/hmac.h>
31
Damien Millerded319c2006-09-01 15:38:36 +100032#include <stdarg.h>
Damien Millere3476ed2006-07-24 14:13:33 +100033#include <string.h>
Damien Millerd7834352006-08-05 12:39:39 +100034#include <signal.h>
Damien Millere3476ed2006-07-24 14:13:33 +100035
Ben Lindstrom06b33aa2001-02-15 03:01:59 +000036#include "xmalloc.h"
Ben Lindstrom06b33aa2001-02-15 03:01:59 +000037#include "log.h"
38#include "cipher.h"
Damien Millerd7834352006-08-05 12:39:39 +100039#include "buffer.h"
40#include "key.h"
Ben Lindstrom06b33aa2001-02-15 03:01:59 +000041#include "kex.h"
42#include "mac.h"
Damien Miller3f941882006-03-31 23:13:02 +110043#include "misc.h"
Ben Lindstrom06b33aa2001-02-15 03:01:59 +000044
Damien Millere45796f2007-06-11 14:01:42 +100045#include "umac.h"
46
Darren Tuckere9b3ad72012-01-17 14:03:34 +110047#include "openbsd-compat/openssl-compat.h"
48
Damien Millere45796f2007-06-11 14:01:42 +100049#define SSH_EVP 1 /* OpenSSL EVP-based MAC */
50#define SSH_UMAC 2 /* UMAC (not integrated with OpenSSL) */
Darren Tucker427e4092012-10-05 11:02:39 +100051#define SSH_UMAC128 3
Damien Millere45796f2007-06-11 14:01:42 +100052
Ben Lindstrom06b33aa2001-02-15 03:01:59 +000053struct {
54 char *name;
Damien Millere45796f2007-06-11 14:01:42 +100055 int type;
Ben Lindstrom6a246412002-06-06 19:48:16 +000056 const EVP_MD * (*mdfunc)(void);
Ben Lindstrom06b33aa2001-02-15 03:01:59 +000057 int truncatebits; /* truncate digest if != 0 */
Damien Millere45796f2007-06-11 14:01:42 +100058 int key_len; /* just for UMAC */
59 int len; /* just for UMAC */
Damien Miller37834af2012-12-12 11:00:37 +110060 int etm; /* Encrypt-then-MAC */
Ben Lindstrom06b33aa2001-02-15 03:01:59 +000061} macs[] = {
Damien Milleraf43a7a2012-12-12 10:46:31 +110062 /* 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 },
Tim Ricea1226822011-08-16 17:29:01 -070065#ifdef HAVE_EVP_SHA256
Damien Milleraf43a7a2012-12-12 10:46:31 +110066 { "hmac-sha2-256", SSH_EVP, EVP_sha256, 0, 0, 0, 0 },
67 { "hmac-sha2-512", SSH_EVP, EVP_sha512, 0, 0, 0, 0 },
Tim Ricea1226822011-08-16 17:29:01 -070068#endif
Damien Milleraf43a7a2012-12-12 10:46:31 +110069 { "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 },
75
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 },
82#endif
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 },
Damien Miller74f13bd2012-12-12 10:46:53 +110085 { "hmac-ripemd160-etm@openssh.com", SSH_EVP, EVP_ripemd160, 0, 0, 0, 1 },
Damien Milleraf43a7a2012-12-12 10:46:31 +110086 { "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 },
88
89 { NULL, 0, NULL, 0, 0, 0, 0 }
Ben Lindstrom06b33aa2001-02-15 03:01:59 +000090};
91
Damien Millere45796f2007-06-11 14:01:42 +100092static void
93mac_setup_by_id(Mac *mac, int which)
94{
95 int evp_len;
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;
102 } else {
103 mac->mac_len = macs[which].len / 8;
104 mac->key_len = macs[which].key_len / 8;
105 mac->umac_ctx = NULL;
106 }
107 if (macs[which].truncatebits != 0)
108 mac->mac_len = macs[which].truncatebits / 8;
Damien Milleraf43a7a2012-12-12 10:46:31 +1100109 mac->etm = macs[which].etm;
Damien Millere45796f2007-06-11 14:01:42 +1000110}
111
Ben Lindstrom06b33aa2001-02-15 03:01:59 +0000112int
Darren Tucker5f3d5be2007-06-05 18:30:18 +1000113mac_setup(Mac *mac, char *name)
Ben Lindstrom06b33aa2001-02-15 03:01:59 +0000114{
Damien Millere45796f2007-06-11 14:01:42 +1000115 int i;
Damien Millereccb9de2005-06-17 12:59:34 +1000116
Ben Lindstrom06b33aa2001-02-15 03:01:59 +0000117 for (i = 0; macs[i].name; i++) {
118 if (strcmp(name, macs[i].name) == 0) {
Damien Millere45796f2007-06-11 14:01:42 +1000119 if (mac != NULL)
120 mac_setup_by_id(mac, i);
Darren Tucker5f3d5be2007-06-05 18:30:18 +1000121 debug2("mac_setup: found %s", name);
Ben Lindstrom06b33aa2001-02-15 03:01:59 +0000122 return (0);
123 }
124 }
Darren Tucker5f3d5be2007-06-05 18:30:18 +1000125 debug2("mac_setup: unknown %s", name);
Ben Lindstrom06b33aa2001-02-15 03:01:59 +0000126 return (-1);
127}
128
Damien Millere45796f2007-06-11 14:01:42 +1000129int
Darren Tucker5f3d5be2007-06-05 18:30:18 +1000130mac_init(Mac *mac)
131{
132 if (mac->key == NULL)
133 fatal("mac_init: no key");
Damien Millere45796f2007-06-11 14:01:42 +1000134 switch (mac->type) {
135 case SSH_EVP:
136 if (mac->evp_md == NULL)
137 return -1;
Damien Millerd0e582c2011-12-19 10:51:39 +1100138 HMAC_CTX_init(&mac->evp_ctx);
Damien Millere45796f2007-06-11 14:01:42 +1000139 HMAC_Init(&mac->evp_ctx, mac->key, mac->key_len, mac->evp_md);
140 return 0;
141 case SSH_UMAC:
142 mac->umac_ctx = umac_new(mac->key);
143 return 0;
Darren Tucker427e4092012-10-05 11:02:39 +1000144 case SSH_UMAC128:
145 mac->umac_ctx = umac128_new(mac->key);
146 return 0;
Damien Millere45796f2007-06-11 14:01:42 +1000147 default:
148 return -1;
149 }
Darren Tucker5f3d5be2007-06-05 18:30:18 +1000150}
151
Ben Lindstrom06b33aa2001-02-15 03:01:59 +0000152u_char *
153mac_compute(Mac *mac, u_int32_t seqno, u_char *data, int datalen)
154{
Ben Lindstrom06b33aa2001-02-15 03:01:59 +0000155 static u_char m[EVP_MAX_MD_SIZE];
Damien Millere45796f2007-06-11 14:01:42 +1000156 u_char b[4], nonce[8];
Ben Lindstrom06b33aa2001-02-15 03:01:59 +0000157
Damien Millereccb9de2005-06-17 12:59:34 +1000158 if (mac->mac_len > sizeof(m))
Damien Millere45796f2007-06-11 14:01:42 +1000159 fatal("mac_compute: mac too long %u %lu",
Darren Tuckerc7e030f2008-06-13 10:58:50 +1000160 mac->mac_len, (u_long)sizeof(m));
Damien Millere45796f2007-06-11 14:01:42 +1000161
162 switch (mac->type) {
163 case SSH_EVP:
164 put_u32(b, seqno);
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);
170 break;
171 case SSH_UMAC:
172 put_u64(nonce, seqno);
173 umac_update(mac->umac_ctx, data, datalen);
174 umac_final(mac->umac_ctx, m, nonce);
175 break;
Darren Tucker427e4092012-10-05 11:02:39 +1000176 case SSH_UMAC128:
177 put_u64(nonce, seqno);
178 umac128_update(mac->umac_ctx, data, datalen);
179 umac128_final(mac->umac_ctx, m, nonce);
180 break;
Damien Millere45796f2007-06-11 14:01:42 +1000181 default:
182 fatal("mac_compute: unknown MAC type");
183 }
Ben Lindstrom06b33aa2001-02-15 03:01:59 +0000184 return (m);
185}
186
Darren Tucker5f3d5be2007-06-05 18:30:18 +1000187void
188mac_clear(Mac *mac)
189{
Damien Millere45796f2007-06-11 14:01:42 +1000190 if (mac->type == SSH_UMAC) {
191 if (mac->umac_ctx != NULL)
192 umac_delete(mac->umac_ctx);
Darren Tucker427e4092012-10-05 11:02:39 +1000193 } else if (mac->type == SSH_UMAC128) {
194 if (mac->umac_ctx != NULL)
195 umac128_delete(mac->umac_ctx);
Damien Millere45796f2007-06-11 14:01:42 +1000196 } else if (mac->evp_md != NULL)
197 HMAC_cleanup(&mac->evp_ctx);
198 mac->evp_md = NULL;
199 mac->umac_ctx = NULL;
Darren Tucker5f3d5be2007-06-05 18:30:18 +1000200}
201
Ben Lindstrom06b33aa2001-02-15 03:01:59 +0000202/* XXX copied from ciphers_valid */
203#define MAC_SEP ","
204int
205mac_valid(const char *names)
206{
207 char *maclist, *cp, *p;
208
209 if (names == NULL || strcmp(names, "") == 0)
210 return (0);
211 maclist = cp = xstrdup(names);
212 for ((p = strsep(&cp, MAC_SEP)); p && *p != '\0';
Damien Miller9f0f5c62001-12-21 14:45:46 +1100213 (p = strsep(&cp, MAC_SEP))) {
Darren Tucker5f3d5be2007-06-05 18:30:18 +1000214 if (mac_setup(NULL, p) < 0) {
Ben Lindstrom06b33aa2001-02-15 03:01:59 +0000215 debug("bad mac %s [%s]", p, names);
216 xfree(maclist);
217 return (0);
218 } else {
219 debug3("mac ok: %s [%s]", p, names);
220 }
221 }
222 debug3("macs ok: [%s]", names);
223 xfree(maclist);
224 return (1);
225}