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2e437378 | 1 | /* $OpenBSD: mac.c,v 1.12 2006/08/03 03:34:42 deraadt Exp $ */ |
3c0ef626 | 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" | |
2e437378 | 27 | |
28 | #include <sys/types.h> | |
3c0ef626 | 29 | |
30 | #include <openssl/hmac.h> | |
31 | ||
2e437378 | 32 | #include <stdarg.h> |
33 | #include <string.h> | |
34 | #include <signal.h> | |
35 | ||
3c0ef626 | 36 | #include "xmalloc.h" |
3c0ef626 | 37 | #include "log.h" |
38 | #include "cipher.h" | |
2e437378 | 39 | #include "buffer.h" |
40 | #include "key.h" | |
3c0ef626 | 41 | #include "kex.h" |
42 | #include "mac.h" | |
2e437378 | 43 | #include "misc.h" |
3c0ef626 | 44 | |
45 | struct { | |
46 | char *name; | |
ff2d7a98 | 47 | const EVP_MD * (*mdfunc)(void); |
3c0ef626 | 48 | int truncatebits; /* truncate digest if != 0 */ |
49 | } macs[] = { | |
50 | { "hmac-sha1", EVP_sha1, 0, }, | |
51 | { "hmac-sha1-96", EVP_sha1, 96 }, | |
52 | { "hmac-md5", EVP_md5, 0 }, | |
53 | { "hmac-md5-96", EVP_md5, 96 }, | |
54 | { "hmac-ripemd160", EVP_ripemd160, 0 }, | |
55 | { "hmac-ripemd160@openssh.com", EVP_ripemd160, 0 }, | |
56 | { NULL, NULL, 0 } | |
57 | }; | |
58 | ||
59 | int | |
60 | mac_init(Mac *mac, char *name) | |
61 | { | |
34fee935 | 62 | int i, evp_len; |
63 | ||
3c0ef626 | 64 | for (i = 0; macs[i].name; i++) { |
65 | if (strcmp(name, macs[i].name) == 0) { | |
66 | if (mac != NULL) { | |
67 | mac->md = (*macs[i].mdfunc)(); | |
34fee935 | 68 | if ((evp_len = EVP_MD_size(mac->md)) <= 0) |
69 | fatal("mac %s len %d", name, evp_len); | |
70 | mac->key_len = mac->mac_len = (u_int)evp_len; | |
3c0ef626 | 71 | if (macs[i].truncatebits != 0) |
72 | mac->mac_len = macs[i].truncatebits/8; | |
73 | } | |
74 | debug2("mac_init: found %s", name); | |
75 | return (0); | |
76 | } | |
77 | } | |
78 | debug2("mac_init: unknown %s", name); | |
79 | return (-1); | |
80 | } | |
81 | ||
82 | u_char * | |
83 | mac_compute(Mac *mac, u_int32_t seqno, u_char *data, int datalen) | |
84 | { | |
85 | HMAC_CTX c; | |
86 | static u_char m[EVP_MAX_MD_SIZE]; | |
87 | u_char b[4]; | |
88 | ||
89 | if (mac->key == NULL) | |
90 | fatal("mac_compute: no key"); | |
34fee935 | 91 | if (mac->mac_len > sizeof(m)) |
3c0ef626 | 92 | fatal("mac_compute: mac too long"); |
93 | HMAC_Init(&c, mac->key, mac->key_len, mac->md); | |
2e437378 | 94 | put_u32(b, seqno); |
3c0ef626 | 95 | HMAC_Update(&c, b, sizeof(b)); |
96 | HMAC_Update(&c, data, datalen); | |
97 | HMAC_Final(&c, m, NULL); | |
98 | HMAC_cleanup(&c); | |
99 | return (m); | |
100 | } | |
101 | ||
102 | /* XXX copied from ciphers_valid */ | |
103 | #define MAC_SEP "," | |
104 | int | |
105 | mac_valid(const char *names) | |
106 | { | |
107 | char *maclist, *cp, *p; | |
108 | ||
109 | if (names == NULL || strcmp(names, "") == 0) | |
110 | return (0); | |
111 | maclist = cp = xstrdup(names); | |
112 | for ((p = strsep(&cp, MAC_SEP)); p && *p != '\0'; | |
e9a17296 | 113 | (p = strsep(&cp, MAC_SEP))) { |
3c0ef626 | 114 | if (mac_init(NULL, p) < 0) { |
115 | debug("bad mac %s [%s]", p, names); | |
116 | xfree(maclist); | |
117 | return (0); | |
118 | } else { | |
119 | debug3("mac ok: %s [%s]", p, names); | |
120 | } | |
121 | } | |
122 | debug3("macs ok: [%s]", names); | |
123 | xfree(maclist); | |
124 | return (1); | |
125 | } |