Annotation of src/usr.bin/ssh/mac.c, Revision 1.19
1.19 ! markus 1: /* $OpenBSD: mac.c,v 1.18 2012/06/28 05:07:45 dtucker 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:
1.12 deraadt 26: #include <sys/types.h>
1.1 markus 27:
28: #include <openssl/hmac.h>
1.11 stevesk 29:
30: #include <string.h>
1.12 deraadt 31: #include <signal.h>
1.1 markus 32:
33: #include "xmalloc.h"
34: #include "log.h"
35: #include "cipher.h"
1.12 deraadt 36: #include "buffer.h"
37: #include "key.h"
1.1 markus 38: #include "kex.h"
39: #include "mac.h"
1.10 djm 40: #include "misc.h"
1.1 markus 41:
1.14 pvalchev 42: #include "umac.h"
43:
44: #define SSH_EVP 1 /* OpenSSL EVP-based MAC */
45: #define SSH_UMAC 2 /* UMAC (not integrated with OpenSSL) */
1.19 ! markus 46: #define SSH_UMAC128 3
1.14 pvalchev 47:
1.1 markus 48: struct {
49: char *name;
1.14 pvalchev 50: int type;
1.5 markus 51: const EVP_MD * (*mdfunc)(void);
1.1 markus 52: int truncatebits; /* truncate digest if != 0 */
1.14 pvalchev 53: int key_len; /* just for UMAC */
54: int len; /* just for UMAC */
1.1 markus 55: } macs[] = {
1.14 pvalchev 56: { "hmac-sha1", SSH_EVP, EVP_sha1, 0, -1, -1 },
57: { "hmac-sha1-96", SSH_EVP, EVP_sha1, 96, -1, -1 },
1.16 djm 58: { "hmac-sha2-256", SSH_EVP, EVP_sha256, 0, -1, -1 },
59: { "hmac-sha2-512", SSH_EVP, EVP_sha512, 0, -1, -1 },
1.14 pvalchev 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 },
1.19 ! markus 65: { "umac-128@openssh.com", SSH_UMAC128, NULL, 0, 128, 128 },
1.14 pvalchev 66: { NULL, 0, NULL, 0, -1, -1 }
1.1 markus 67: };
68:
1.14 pvalchev 69: static void
70: mac_setup_by_id(Mac *mac, int which)
71: {
72: int evp_len;
73: mac->type = macs[which].type;
74: if (mac->type == SSH_EVP) {
75: mac->evp_md = (*macs[which].mdfunc)();
76: if ((evp_len = EVP_MD_size(mac->evp_md)) <= 0)
77: fatal("mac %s len %d", mac->name, evp_len);
78: mac->key_len = mac->mac_len = (u_int)evp_len;
79: } else {
80: mac->mac_len = macs[which].len / 8;
81: mac->key_len = macs[which].key_len / 8;
82: mac->umac_ctx = NULL;
83: }
84: if (macs[which].truncatebits != 0)
85: mac->mac_len = macs[which].truncatebits / 8;
86: }
87:
1.1 markus 88: int
1.13 djm 89: mac_setup(Mac *mac, char *name)
1.1 markus 90: {
1.14 pvalchev 91: int i;
1.7 djm 92:
1.1 markus 93: for (i = 0; macs[i].name; i++) {
94: if (strcmp(name, macs[i].name) == 0) {
1.14 pvalchev 95: if (mac != NULL)
96: mac_setup_by_id(mac, i);
1.13 djm 97: debug2("mac_setup: found %s", name);
1.1 markus 98: return (0);
99: }
100: }
1.13 djm 101: debug2("mac_setup: unknown %s", name);
1.1 markus 102: return (-1);
103: }
104:
1.14 pvalchev 105: int
1.13 djm 106: mac_init(Mac *mac)
107: {
108: if (mac->key == NULL)
109: fatal("mac_init: no key");
1.14 pvalchev 110: switch (mac->type) {
111: case SSH_EVP:
112: if (mac->evp_md == NULL)
113: return -1;
1.17 djm 114: HMAC_CTX_init(&mac->evp_ctx);
1.14 pvalchev 115: HMAC_Init(&mac->evp_ctx, mac->key, mac->key_len, mac->evp_md);
116: return 0;
117: case SSH_UMAC:
118: mac->umac_ctx = umac_new(mac->key);
119: return 0;
1.19 ! markus 120: case SSH_UMAC128:
! 121: mac->umac_ctx = umac128_new(mac->key);
! 122: return 0;
1.14 pvalchev 123: default:
124: return -1;
125: }
1.13 djm 126: }
127:
1.1 markus 128: u_char *
129: mac_compute(Mac *mac, u_int32_t seqno, u_char *data, int datalen)
130: {
131: static u_char m[EVP_MAX_MD_SIZE];
1.14 pvalchev 132: u_char b[4], nonce[8];
1.1 markus 133:
1.7 djm 134: if (mac->mac_len > sizeof(m))
1.14 pvalchev 135: fatal("mac_compute: mac too long %u %lu",
1.15 dtucker 136: mac->mac_len, (u_long)sizeof(m));
1.14 pvalchev 137:
138: switch (mac->type) {
139: case SSH_EVP:
140: put_u32(b, seqno);
141: /* reset HMAC context */
142: HMAC_Init(&mac->evp_ctx, NULL, 0, NULL);
143: HMAC_Update(&mac->evp_ctx, b, sizeof(b));
144: HMAC_Update(&mac->evp_ctx, data, datalen);
145: HMAC_Final(&mac->evp_ctx, m, NULL);
146: break;
147: case SSH_UMAC:
148: put_u64(nonce, seqno);
149: umac_update(mac->umac_ctx, data, datalen);
150: umac_final(mac->umac_ctx, m, nonce);
151: break;
1.19 ! markus 152: case SSH_UMAC128:
! 153: put_u64(nonce, seqno);
! 154: umac128_update(mac->umac_ctx, data, datalen);
! 155: umac128_final(mac->umac_ctx, m, nonce);
! 156: break;
1.14 pvalchev 157: default:
158: fatal("mac_compute: unknown MAC type");
159: }
1.1 markus 160: return (m);
161: }
162:
1.13 djm 163: void
164: mac_clear(Mac *mac)
165: {
1.14 pvalchev 166: if (mac->type == SSH_UMAC) {
167: if (mac->umac_ctx != NULL)
168: umac_delete(mac->umac_ctx);
1.19 ! markus 169: } else if (mac->type == SSH_UMAC128) {
! 170: if (mac->umac_ctx != NULL)
! 171: umac128_delete(mac->umac_ctx);
1.14 pvalchev 172: } else if (mac->evp_md != NULL)
173: HMAC_cleanup(&mac->evp_ctx);
174: mac->evp_md = NULL;
175: mac->umac_ctx = NULL;
1.13 djm 176: }
177:
1.1 markus 178: /* XXX copied from ciphers_valid */
179: #define MAC_SEP ","
180: int
181: mac_valid(const char *names)
182: {
183: char *maclist, *cp, *p;
184:
185: if (names == NULL || strcmp(names, "") == 0)
186: return (0);
187: maclist = cp = xstrdup(names);
188: for ((p = strsep(&cp, MAC_SEP)); p && *p != '\0';
1.3 deraadt 189: (p = strsep(&cp, MAC_SEP))) {
1.13 djm 190: if (mac_setup(NULL, p) < 0) {
1.1 markus 191: debug("bad mac %s [%s]", p, names);
192: xfree(maclist);
193: return (0);
194: } else {
195: debug3("mac ok: %s [%s]", p, names);
196: }
197: }
198: debug3("macs ok: [%s]", names);
199: xfree(maclist);
200: return (1);
201: }
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