eap_server_md5.c revision 214734 
1/*
2 * hostapd / EAP-MD5 server
3 * Copyright (c) 2004-2007, Jouni Malinen <j@w1.fi>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 *
9 * Alternatively, this software may be distributed under the terms of BSD
10 * license.
11 *
12 * See README and COPYING for more details.
13 */
14
15#include "includes.h"
16
17#include "common.h"
18#include "eap_i.h"
19#include "eap_common/chap.h"
20
21
22#define CHALLENGE_LEN 16
23
24struct eap_md5_data {
25	u8 challenge[CHALLENGE_LEN];
26	enum { CONTINUE, SUCCESS, FAILURE } state;
27};
28
29
30static void * eap_md5_init(struct eap_sm *sm)
31{
32	struct eap_md5_data *data;
33
34	data = os_zalloc(sizeof(*data));
35	if (data == NULL)
36		return NULL;
37	data->state = CONTINUE;
38
39	return data;
40}
41
42
43static void eap_md5_reset(struct eap_sm *sm, void *priv)
44{
45	struct eap_md5_data *data = priv;
46	os_free(data);
47}
48
49
50static struct wpabuf * eap_md5_buildReq(struct eap_sm *sm, void *priv, u8 id)
51{
52	struct eap_md5_data *data = priv;
53	struct wpabuf *req;
54
55	if (os_get_random(data->challenge, CHALLENGE_LEN)) {
56		wpa_printf(MSG_ERROR, "EAP-MD5: Failed to get random data");
57		data->state = FAILURE;
58		return NULL;
59	}
60
61	req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_MD5, 1 + CHALLENGE_LEN,
62			    EAP_CODE_REQUEST, id);
63	if (req == NULL) {
64		wpa_printf(MSG_ERROR, "EAP-MD5: Failed to allocate memory for "
65			   "request");
66		data->state = FAILURE;
67		return NULL;
68	}
69
70	wpabuf_put_u8(req, CHALLENGE_LEN);
71	wpabuf_put_data(req, data->challenge, CHALLENGE_LEN);
72	wpa_hexdump(MSG_MSGDUMP, "EAP-MD5: Challenge", data->challenge,
73		    CHALLENGE_LEN);
74
75	data->state = CONTINUE;
76
77	return req;
78}
79
80
81static Boolean eap_md5_check(struct eap_sm *sm, void *priv,
82			     struct wpabuf *respData)
83{
84	const u8 *pos;
85	size_t len;
86
87	pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_MD5, respData, &len);
88	if (pos == NULL || len < 1) {
89		wpa_printf(MSG_INFO, "EAP-MD5: Invalid frame");
90		return TRUE;
91	}
92	if (*pos != CHAP_MD5_LEN || 1 + CHAP_MD5_LEN > len) {
93		wpa_printf(MSG_INFO, "EAP-MD5: Invalid response "
94			   "(response_len=%d payload_len=%lu",
95			   *pos, (unsigned long) len);
96		return TRUE;
97	}
98
99	return FALSE;
100}
101
102
103static void eap_md5_process(struct eap_sm *sm, void *priv,
104			    struct wpabuf *respData)
105{
106	struct eap_md5_data *data = priv;
107	const u8 *pos;
108	size_t plen;
109	u8 hash[CHAP_MD5_LEN], id;
110
111	if (sm->user == NULL || sm->user->password == NULL ||
112	    sm->user->password_hash) {
113		wpa_printf(MSG_INFO, "EAP-MD5: Plaintext password not "
114			   "configured");
115		data->state = FAILURE;
116		return;
117	}
118
119	pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_MD5, respData, &plen);
120	if (pos == NULL || *pos != CHAP_MD5_LEN || plen < 1 + CHAP_MD5_LEN)
121		return; /* Should not happen - frame already validated */
122
123	pos++; /* Skip response len */
124	wpa_hexdump(MSG_MSGDUMP, "EAP-MD5: Response", pos, CHAP_MD5_LEN);
125
126	id = eap_get_id(respData);
127	chap_md5(id, sm->user->password, sm->user->password_len,
128		 data->challenge, CHALLENGE_LEN, hash);
129
130	if (os_memcmp(hash, pos, CHAP_MD5_LEN) == 0) {
131		wpa_printf(MSG_DEBUG, "EAP-MD5: Done - Success");
132		data->state = SUCCESS;
133	} else {
134		wpa_printf(MSG_DEBUG, "EAP-MD5: Done - Failure");
135		data->state = FAILURE;
136	}
137}
138
139
140static Boolean eap_md5_isDone(struct eap_sm *sm, void *priv)
141{
142	struct eap_md5_data *data = priv;
143	return data->state != CONTINUE;
144}
145
146
147static Boolean eap_md5_isSuccess(struct eap_sm *sm, void *priv)
148{
149	struct eap_md5_data *data = priv;
150	return data->state == SUCCESS;
151}
152
153
154int eap_server_md5_register(void)
155{
156	struct eap_method *eap;
157	int ret;
158
159	eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION,
160				      EAP_VENDOR_IETF, EAP_TYPE_MD5, "MD5");
161	if (eap == NULL)
162		return -1;
163
164	eap->init = eap_md5_init;
165	eap->reset = eap_md5_reset;
166	eap->buildReq = eap_md5_buildReq;
167	eap->check = eap_md5_check;
168	eap->process = eap_md5_process;
169	eap->isDone = eap_md5_isDone;
170	eap->isSuccess = eap_md5_isSuccess;
171
172	ret = eap_server_method_register(eap);
173	if (ret)
174		eap_server_method_free(eap);
175	return ret;
176}
177