eap_server_md5.c revision 8d520ff1dc2da35cdca849e982051b86468016d8 
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 "crypto/random.h"
19#include "eap_i.h"
20#include "eap_common/chap.h"
21
22
23#define CHALLENGE_LEN 16
24
25struct eap_md5_data {
26	u8 challenge[CHALLENGE_LEN];
27	enum { CONTINUE, SUCCESS, FAILURE } state;
28};
29
30
31static void * eap_md5_init(struct eap_sm *sm)
32{
33	struct eap_md5_data *data;
34
35	data = os_zalloc(sizeof(*data));
36	if (data == NULL)
37		return NULL;
38	data->state = CONTINUE;
39
40	return data;
41}
42
43
44static void eap_md5_reset(struct eap_sm *sm, void *priv)
45{
46	struct eap_md5_data *data = priv;
47	os_free(data);
48}
49
50
51static struct wpabuf * eap_md5_buildReq(struct eap_sm *sm, void *priv, u8 id)
52{
53	struct eap_md5_data *data = priv;
54	struct wpabuf *req;
55
56	if (random_get_bytes(data->challenge, CHALLENGE_LEN)) {
57		wpa_printf(MSG_ERROR, "EAP-MD5: Failed to get random data");
58		data->state = FAILURE;
59		return NULL;
60	}
61
62	req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_MD5, 1 + CHALLENGE_LEN,
63			    EAP_CODE_REQUEST, id);
64	if (req == NULL) {
65		wpa_printf(MSG_ERROR, "EAP-MD5: Failed to allocate memory for "
66			   "request");
67		data->state = FAILURE;
68		return NULL;
69	}
70
71	wpabuf_put_u8(req, CHALLENGE_LEN);
72	wpabuf_put_data(req, data->challenge, CHALLENGE_LEN);
73	wpa_hexdump(MSG_MSGDUMP, "EAP-MD5: Challenge", data->challenge,
74		    CHALLENGE_LEN);
75
76	data->state = CONTINUE;
77
78	return req;
79}
80
81
82static Boolean eap_md5_check(struct eap_sm *sm, void *priv,
83			     struct wpabuf *respData)
84{
85	const u8 *pos;
86	size_t len;
87
88	pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_MD5, respData, &len);
89	if (pos == NULL || len < 1) {
90		wpa_printf(MSG_INFO, "EAP-MD5: Invalid frame");
91		return TRUE;
92	}
93	if (*pos != CHAP_MD5_LEN || 1 + CHAP_MD5_LEN > len) {
94		wpa_printf(MSG_INFO, "EAP-MD5: Invalid response "
95			   "(response_len=%d payload_len=%lu",
96			   *pos, (unsigned long) len);
97		return TRUE;
98	}
99
100	return FALSE;
101}
102
103
104static void eap_md5_process(struct eap_sm *sm, void *priv,
105			    struct wpabuf *respData)
106{
107	struct eap_md5_data *data = priv;
108	const u8 *pos;
109	size_t plen;
110	u8 hash[CHAP_MD5_LEN], id;
111
112	if (sm->user == NULL || sm->user->password == NULL ||
113	    sm->user->password_hash) {
114		wpa_printf(MSG_INFO, "EAP-MD5: Plaintext password not "
115			   "configured");
116		data->state = FAILURE;
117		return;
118	}
119
120	pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_MD5, respData, &plen);
121	if (pos == NULL || *pos != CHAP_MD5_LEN || plen < 1 + CHAP_MD5_LEN)
122		return; /* Should not happen - frame already validated */
123
124	pos++; /* Skip response len */
125	wpa_hexdump(MSG_MSGDUMP, "EAP-MD5: Response", pos, CHAP_MD5_LEN);
126
127	id = eap_get_id(respData);
128	chap_md5(id, sm->user->password, sm->user->password_len,
129		 data->challenge, CHALLENGE_LEN, hash);
130
131	if (os_memcmp(hash, pos, CHAP_MD5_LEN) == 0) {
132		wpa_printf(MSG_DEBUG, "EAP-MD5: Done - Success");
133		data->state = SUCCESS;
134	} else {
135		wpa_printf(MSG_DEBUG, "EAP-MD5: Done - Failure");
136		data->state = FAILURE;
137	}
138}
139
140
141static Boolean eap_md5_isDone(struct eap_sm *sm, void *priv)
142{
143	struct eap_md5_data *data = priv;
144	return data->state != CONTINUE;
145}
146
147
148static Boolean eap_md5_isSuccess(struct eap_sm *sm, void *priv)
149{
150	struct eap_md5_data *data = priv;
151	return data->state == SUCCESS;
152}
153
154
155int eap_server_md5_register(void)
156{
157	struct eap_method *eap;
158	int ret;
159
160	eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION,
161				      EAP_VENDOR_IETF, EAP_TYPE_MD5, "MD5");
162	if (eap == NULL)
163		return -1;
164
165	eap->init = eap_md5_init;
166	eap->reset = eap_md5_reset;
167	eap->buildReq = eap_md5_buildReq;
168	eap->check = eap_md5_check;
169	eap->process = eap_md5_process;
170	eap->isDone = eap_md5_isDone;
171	eap->isSuccess = eap_md5_isSuccess;
172
173	ret = eap_server_method_register(eap);
174	if (ret)
175		eap_server_method_free(eap);
176	return ret;
177}
178