Annotation of src/usr.bin/ssh/mac.c, Revision 1.11
1.11 ! stevesk 1: /* $OpenBSD: mac.c,v 1.10 2006/03/30 09:58:15 djm Exp $ */
1.1 markus 2: /*
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"
27:
28: #include <openssl/hmac.h>
1.11 ! stevesk 29:
! 30: #include <string.h>
1.1 markus 31:
32: #include "xmalloc.h"
33: #include "log.h"
34: #include "cipher.h"
35: #include "kex.h"
36: #include "mac.h"
1.10 djm 37: #include "misc.h"
1.1 markus 38:
39: struct {
40: char *name;
1.5 markus 41: const EVP_MD * (*mdfunc)(void);
1.1 markus 42: int truncatebits; /* truncate digest if != 0 */
43: } macs[] = {
44: { "hmac-sha1", EVP_sha1, 0, },
45: { "hmac-sha1-96", EVP_sha1, 96 },
46: { "hmac-md5", EVP_md5, 0 },
47: { "hmac-md5-96", EVP_md5, 96 },
48: { "hmac-ripemd160", EVP_ripemd160, 0 },
49: { "hmac-ripemd160@openssh.com", EVP_ripemd160, 0 },
1.2 markus 50: { NULL, NULL, 0 }
1.1 markus 51: };
52:
53: int
54: mac_init(Mac *mac, char *name)
55: {
1.7 djm 56: int i, evp_len;
57:
1.1 markus 58: for (i = 0; macs[i].name; i++) {
59: if (strcmp(name, macs[i].name) == 0) {
60: if (mac != NULL) {
61: mac->md = (*macs[i].mdfunc)();
1.7 djm 62: if ((evp_len = EVP_MD_size(mac->md)) <= 0)
63: fatal("mac %s len %d", name, evp_len);
64: mac->key_len = mac->mac_len = (u_int)evp_len;
1.1 markus 65: if (macs[i].truncatebits != 0)
66: mac->mac_len = macs[i].truncatebits/8;
67: }
68: debug2("mac_init: found %s", name);
69: return (0);
70: }
71: }
72: debug2("mac_init: unknown %s", name);
73: return (-1);
74: }
75:
76: u_char *
77: mac_compute(Mac *mac, u_int32_t seqno, u_char *data, int datalen)
78: {
79: HMAC_CTX c;
80: static u_char m[EVP_MAX_MD_SIZE];
81: u_char b[4];
82:
83: if (mac->key == NULL)
84: fatal("mac_compute: no key");
1.7 djm 85: if (mac->mac_len > sizeof(m))
1.1 markus 86: fatal("mac_compute: mac too long");
87: HMAC_Init(&c, mac->key, mac->key_len, mac->md);
1.10 djm 88: put_u32(b, seqno);
1.1 markus 89: HMAC_Update(&c, b, sizeof(b));
90: HMAC_Update(&c, data, datalen);
91: HMAC_Final(&c, m, NULL);
92: HMAC_cleanup(&c);
93: return (m);
94: }
95:
96: /* XXX copied from ciphers_valid */
97: #define MAC_SEP ","
98: int
99: mac_valid(const char *names)
100: {
101: char *maclist, *cp, *p;
102:
103: if (names == NULL || strcmp(names, "") == 0)
104: return (0);
105: maclist = cp = xstrdup(names);
106: for ((p = strsep(&cp, MAC_SEP)); p && *p != '\0';
1.3 deraadt 107: (p = strsep(&cp, MAC_SEP))) {
1.1 markus 108: if (mac_init(NULL, p) < 0) {
109: debug("bad mac %s [%s]", p, names);
110: xfree(maclist);
111: return (0);
112: } else {
113: debug3("mac ok: %s [%s]", p, names);
114: }
115: }
116: debug3("macs ok: [%s]", names);
117: xfree(maclist);
118: return (1);
119: }