1 /*
2 * LibSylph -- E-Mail client library
3 * Copyright (C) 1999-2006 Hiroyuki Yamamoto
4 *
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2.1 of the License, or (at your option) any later version.
9 *
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Lesser General Public License for more details.
14 *
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with this library; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18 */
19
20 #ifdef HAVE_CONFIG_H
21 # include "config.h"
22 #endif
23
24 #include <glib.h>
25 #include <string.h>
26
27 #include "md5.h"
28 #include "md5_hmac.h"
29
30 /*
31 ** Function: md5_hmac_get
32 ** taken from the file rfc2104.txt
33 ** originally written by Martin Schaaf <mascha@ma-scha.de>
34 ** rewritten by Hiroyuki Yamamoto <hiro-y@kcn.ne.jp>
35 */
36 static SMD5*
md5_hmac_get(const guchar * text,gint text_len,const guchar * key,gint key_len)37 md5_hmac_get(const guchar *text, gint text_len,
38 const guchar *key, gint key_len)
39 {
40 SMD5 *md5;
41 guchar k_ipad[64]; /* inner padding -
42 * key XORd with ipad
43 */
44 guchar k_opad[64]; /* outer padding -
45 * key XORd with opad
46 */
47 guchar digest[S_GNET_MD5_HASH_LENGTH];
48 gint i;
49
50 /* start out by storing key in pads */
51 memset(k_ipad, 0, sizeof k_ipad);
52 memset(k_opad, 0, sizeof k_opad);
53
54 if (key_len > 64) {
55 /* if key is longer than 64 bytes reset it to key=MD5(key) */
56 SMD5 *tmd5;
57
58 tmd5 = s_gnet_md5_new(key, key_len);
59 memcpy(k_ipad, s_gnet_md5_get_digest(tmd5),
60 S_GNET_MD5_HASH_LENGTH);
61 memcpy(k_opad, s_gnet_md5_get_digest(tmd5),
62 S_GNET_MD5_HASH_LENGTH);
63 s_gnet_md5_delete(tmd5);
64 } else {
65 memcpy(k_ipad, key, key_len);
66 memcpy(k_opad, key, key_len);
67 }
68
69 /*
70 * the HMAC_MD5 transform looks like:
71 *
72 * MD5(K XOR opad, MD5(K XOR ipad, text))
73 *
74 * where K is an n byte key
75 * ipad is the byte 0x36 repeated 64 times
76 * opad is the byte 0x5c repeated 64 times
77 * and text is the data being protected
78 */
79
80
81 /* XOR key with ipad and opad values */
82 for (i = 0; i < 64; i++) {
83 k_ipad[i] ^= 0x36;
84 k_opad[i] ^= 0x5c;
85 }
86
87 /*
88 * perform inner MD5
89 */
90 md5 = s_gnet_md5_new_incremental(); /* init context for 1st
91 * pass */
92 s_gnet_md5_update(md5, k_ipad, 64); /* start with inner pad */
93 s_gnet_md5_update(md5, text, text_len); /* then text of datagram */
94 s_gnet_md5_final(md5); /* finish up 1st pass */
95 memcpy(digest, s_gnet_md5_get_digest(md5), S_GNET_MD5_HASH_LENGTH);
96 s_gnet_md5_delete(md5);
97
98 /*
99 * perform outer MD5
100 */
101 md5 = s_gnet_md5_new_incremental(); /* init context for 2nd
102 * pass */
103 s_gnet_md5_update(md5, k_opad, 64); /* start with outer pad */
104 s_gnet_md5_update(md5, digest, 16); /* then results of 1st
105 * hash */
106 s_gnet_md5_final(md5); /* finish up 2nd pass */
107
108 return md5;
109 }
110
111 void
md5_hmac(guchar * digest,const guchar * text,gint text_len,const guchar * key,gint key_len)112 md5_hmac(guchar *digest,
113 const guchar *text, gint text_len,
114 const guchar *key, gint key_len)
115 {
116 SMD5 *md5;
117
118 md5 = md5_hmac_get(text, text_len, key, key_len);
119 memcpy(digest, s_gnet_md5_get_digest(md5), S_GNET_MD5_HASH_LENGTH);
120 s_gnet_md5_delete(md5);
121 }
122
123 void
md5_hex_hmac(gchar * hexdigest,const guchar * text,gint text_len,const guchar * key,gint key_len)124 md5_hex_hmac(gchar *hexdigest,
125 const guchar *text, gint text_len,
126 const guchar *key, gint key_len)
127 {
128 SMD5 *md5;
129
130 md5 = md5_hmac_get(text, text_len, key, key_len);
131 s_gnet_md5_copy_string(md5, hexdigest);
132 hexdigest[S_GNET_MD5_HASH_LENGTH * 2] = '\0';
133 s_gnet_md5_delete(md5);
134 }
135