blob: 34464659ad66ca17aa7f70c7aa8e98f54f0475a2 [file] [log] [blame]
Damien Millere45796f2007-06-11 14:01:42 +10001/* $OpenBSD: mac.c,v 1.14 2007/06/07 19:37:34 pvalchev 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
47#define SSH_EVP 1 /* OpenSSL EVP-based MAC */
48#define SSH_UMAC 2 /* UMAC (not integrated with OpenSSL) */
49
Ben Lindstrom06b33aa2001-02-15 03:01:59 +000050struct {
51 char *name;
Damien Millere45796f2007-06-11 14:01:42 +100052 int type;
Ben Lindstrom6a246412002-06-06 19:48:16 +000053 const EVP_MD * (*mdfunc)(void);
Ben Lindstrom06b33aa2001-02-15 03:01:59 +000054 int truncatebits; /* truncate digest if != 0 */
Damien Millere45796f2007-06-11 14:01:42 +100055 int key_len; /* just for UMAC */
56 int len; /* just for UMAC */
Ben Lindstrom06b33aa2001-02-15 03:01:59 +000057} macs[] = {
Damien Millere45796f2007-06-11 14:01:42 +100058 { "hmac-sha1", SSH_EVP, EVP_sha1, 0, -1, -1 },
59 { "hmac-sha1-96", SSH_EVP, EVP_sha1, 96, -1, -1 },
60 { "hmac-md5", SSH_EVP, EVP_md5, 0, -1, -1 },
61 { "hmac-md5-96", SSH_EVP, EVP_md5, 96, -1, -1 },
62 { "hmac-ripemd160", SSH_EVP, EVP_ripemd160, 0, -1, -1 },
63 { "hmac-ripemd160@openssh.com", SSH_EVP, EVP_ripemd160, 0, -1, -1 },
64 { "umac-64@openssh.com", SSH_UMAC, NULL, 0, 128, 64 },
65 { NULL, 0, NULL, 0, -1, -1 }
Ben Lindstrom06b33aa2001-02-15 03:01:59 +000066};
67
Damien Millere45796f2007-06-11 14:01:42 +100068static void
69mac_setup_by_id(Mac *mac, int which)
70{
71 int evp_len;
72 mac->type = macs[which].type;
73 if (mac->type == SSH_EVP) {
74 mac->evp_md = (*macs[which].mdfunc)();
75 if ((evp_len = EVP_MD_size(mac->evp_md)) <= 0)
76 fatal("mac %s len %d", mac->name, evp_len);
77 mac->key_len = mac->mac_len = (u_int)evp_len;
78 } else {
79 mac->mac_len = macs[which].len / 8;
80 mac->key_len = macs[which].key_len / 8;
81 mac->umac_ctx = NULL;
82 }
83 if (macs[which].truncatebits != 0)
84 mac->mac_len = macs[which].truncatebits / 8;
85}
86
Ben Lindstrom06b33aa2001-02-15 03:01:59 +000087int
Darren Tucker5f3d5be2007-06-05 18:30:18 +100088mac_setup(Mac *mac, char *name)
Ben Lindstrom06b33aa2001-02-15 03:01:59 +000089{
Damien Millere45796f2007-06-11 14:01:42 +100090 int i;
Damien Millereccb9de2005-06-17 12:59:34 +100091
Ben Lindstrom06b33aa2001-02-15 03:01:59 +000092 for (i = 0; macs[i].name; i++) {
93 if (strcmp(name, macs[i].name) == 0) {
Damien Millere45796f2007-06-11 14:01:42 +100094 if (mac != NULL)
95 mac_setup_by_id(mac, i);
Darren Tucker5f3d5be2007-06-05 18:30:18 +100096 debug2("mac_setup: found %s", name);
Ben Lindstrom06b33aa2001-02-15 03:01:59 +000097 return (0);
98 }
99 }
Darren Tucker5f3d5be2007-06-05 18:30:18 +1000100 debug2("mac_setup: unknown %s", name);
Ben Lindstrom06b33aa2001-02-15 03:01:59 +0000101 return (-1);
102}
103
Damien Millere45796f2007-06-11 14:01:42 +1000104int
Darren Tucker5f3d5be2007-06-05 18:30:18 +1000105mac_init(Mac *mac)
106{
107 if (mac->key == NULL)
108 fatal("mac_init: no key");
Damien Millere45796f2007-06-11 14:01:42 +1000109 switch (mac->type) {
110 case SSH_EVP:
111 if (mac->evp_md == NULL)
112 return -1;
113 HMAC_Init(&mac->evp_ctx, mac->key, mac->key_len, mac->evp_md);
114 return 0;
115 case SSH_UMAC:
116 mac->umac_ctx = umac_new(mac->key);
117 return 0;
118 default:
119 return -1;
120 }
Darren Tucker5f3d5be2007-06-05 18:30:18 +1000121}
122
Ben Lindstrom06b33aa2001-02-15 03:01:59 +0000123u_char *
124mac_compute(Mac *mac, u_int32_t seqno, u_char *data, int datalen)
125{
Ben Lindstrom06b33aa2001-02-15 03:01:59 +0000126 static u_char m[EVP_MAX_MD_SIZE];
Damien Millere45796f2007-06-11 14:01:42 +1000127 u_char b[4], nonce[8];
Ben Lindstrom06b33aa2001-02-15 03:01:59 +0000128
Damien Millereccb9de2005-06-17 12:59:34 +1000129 if (mac->mac_len > sizeof(m))
Damien Millere45796f2007-06-11 14:01:42 +1000130 fatal("mac_compute: mac too long %u %lu",
131 mac->mac_len, sizeof(m));
132
133 switch (mac->type) {
134 case SSH_EVP:
135 put_u32(b, seqno);
136 /* reset HMAC context */
137 HMAC_Init(&mac->evp_ctx, NULL, 0, NULL);
138 HMAC_Update(&mac->evp_ctx, b, sizeof(b));
139 HMAC_Update(&mac->evp_ctx, data, datalen);
140 HMAC_Final(&mac->evp_ctx, m, NULL);
141 break;
142 case SSH_UMAC:
143 put_u64(nonce, seqno);
144 umac_update(mac->umac_ctx, data, datalen);
145 umac_final(mac->umac_ctx, m, nonce);
146 break;
147 default:
148 fatal("mac_compute: unknown MAC type");
149 }
Ben Lindstrom06b33aa2001-02-15 03:01:59 +0000150 return (m);
151}
152
Darren Tucker5f3d5be2007-06-05 18:30:18 +1000153void
154mac_clear(Mac *mac)
155{
Damien Millere45796f2007-06-11 14:01:42 +1000156 if (mac->type == SSH_UMAC) {
157 if (mac->umac_ctx != NULL)
158 umac_delete(mac->umac_ctx);
159 } else if (mac->evp_md != NULL)
160 HMAC_cleanup(&mac->evp_ctx);
161 mac->evp_md = NULL;
162 mac->umac_ctx = NULL;
Darren Tucker5f3d5be2007-06-05 18:30:18 +1000163}
164
Ben Lindstrom06b33aa2001-02-15 03:01:59 +0000165/* XXX copied from ciphers_valid */
166#define MAC_SEP ","
167int
168mac_valid(const char *names)
169{
170 char *maclist, *cp, *p;
171
172 if (names == NULL || strcmp(names, "") == 0)
173 return (0);
174 maclist = cp = xstrdup(names);
175 for ((p = strsep(&cp, MAC_SEP)); p && *p != '\0';
Damien Miller9f0f5c62001-12-21 14:45:46 +1100176 (p = strsep(&cp, MAC_SEP))) {
Darren Tucker5f3d5be2007-06-05 18:30:18 +1000177 if (mac_setup(NULL, p) < 0) {
Ben Lindstrom06b33aa2001-02-15 03:01:59 +0000178 debug("bad mac %s [%s]", p, names);
179 xfree(maclist);
180 return (0);
181 } else {
182 debug3("mac ok: %s [%s]", p, names);
183 }
184 }
185 debug3("macs ok: [%s]", names);
186 xfree(maclist);
187 return (1);
188}