2 * chap-md5.c - New CHAP/MD5 implementation.
4 * Copyright (c) 2003 Paul Mackerras. All rights reserved.
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
13 * 2. The name(s) of the authors of this software must not be used to
14 * endorse or promote products derived from this software without
15 * prior written permission.
17 * 3. Redistributions of any form whatsoever must retain the following
19 * "This product includes software developed by Paul Mackerras
20 * <paulus@samba.org>".
22 * THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
23 * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
24 * AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
25 * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
26 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
27 * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
28 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
31 #define RCSID "$Id: chap-md5.c,v 1.4 2004/11/09 22:39:25 paulus Exp $"
45 #define MD5_HASH_SIZE 16
46 #define MD5_MIN_CHALLENGE 16
47 #define MD5_MAX_CHALLENGE 24
50 chap_md5_generate_challenge(unsigned char *cp)
54 clen = (int)(drand48() * (MD5_MAX_CHALLENGE - MD5_MIN_CHALLENGE))
57 random_bytes(cp, clen);
61 chap_md5_verify_response(int id, char *name,
62 unsigned char *secret, int secret_len,
63 unsigned char *challenge, unsigned char *response,
64 char *message, int message_space)
67 unsigned char idbyte = id;
68 unsigned char hash[MD5_HASH_SIZE];
69 int challenge_len, response_len;
71 challenge_len = *challenge++;
72 response_len = *response++;
73 if (response_len == MD5_HASH_SIZE) {
74 /* Generate hash of ID, secret, challenge */
76 MD5_Update(&ctx, &idbyte, 1);
77 MD5_Update(&ctx, secret, secret_len);
78 MD5_Update(&ctx, challenge, challenge_len);
79 MD5_Final(hash, &ctx);
81 /* Test if our hash matches the peer's response */
82 if (memcmp(hash, response, MD5_HASH_SIZE) == 0) {
83 slprintf(message, message_space, "Access granted");
87 slprintf(message, message_space, "Access denied");
92 chap_md5_make_response(unsigned char *response, int id, char *our_name,
93 unsigned char *challenge, char *secret, int secret_len,
94 unsigned char *private)
97 unsigned char idbyte = id;
98 int challenge_len = *challenge++;
101 MD5_Update(&ctx, &idbyte, 1);
102 MD5_Update(&ctx, (u_char *)secret, secret_len);
103 MD5_Update(&ctx, challenge, challenge_len);
104 MD5_Final(&response[1], &ctx);
105 response[0] = MD5_HASH_SIZE;
108 static struct chap_digest_type md5_digest = {
110 chap_md5_generate_challenge,
111 chap_md5_verify_response,
112 chap_md5_make_response,
113 NULL, /* check_success */
114 NULL, /* handle_failure */
120 chap_register_digest(&md5_digest);