eap_gtc.c revision 189251 
1/*
2 * EAP peer method: EAP-GTC (RFC 3748)
3 * Copyright (c) 2004-2006, 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
20
21struct eap_gtc_data {
22	int prefix;
23};
24
25
26static void * eap_gtc_init(struct eap_sm *sm)
27{
28	struct eap_gtc_data *data;
29	data = os_zalloc(sizeof(*data));
30	if (data == NULL)
31		return NULL;
32
33	if (sm->m && sm->m->vendor == EAP_VENDOR_IETF &&
34	    sm->m->method == EAP_TYPE_FAST) {
35		wpa_printf(MSG_DEBUG, "EAP-GTC: EAP-FAST tunnel - use prefix "
36			   "with challenge/response");
37		data->prefix = 1;
38	}
39	return data;
40}
41
42
43static void eap_gtc_deinit(struct eap_sm *sm, void *priv)
44{
45	struct eap_gtc_data *data = priv;
46	os_free(data);
47}
48
49
50static struct wpabuf * eap_gtc_process(struct eap_sm *sm, void *priv,
51				       struct eap_method_ret *ret,
52				       const struct wpabuf *reqData)
53{
54	struct eap_gtc_data *data = priv;
55	struct wpabuf *resp;
56	const u8 *pos, *password, *identity;
57	size_t password_len, identity_len, len, plen;
58	int otp;
59	u8 id;
60
61	pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_GTC, reqData, &len);
62	if (pos == NULL) {
63		ret->ignore = TRUE;
64		return NULL;
65	}
66	id = eap_get_id(reqData);
67
68	wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-GTC: Request message", pos, len);
69	if (data->prefix &&
70	    (len < 10 || os_memcmp(pos, "CHALLENGE=", 10) != 0)) {
71		wpa_printf(MSG_DEBUG, "EAP-GTC: Challenge did not start with "
72			   "expected prefix");
73
74		/* Send an empty response in order to allow tunneled
75		 * acknowledgement of the failure. This will also cover the
76		 * error case which seems to use EAP-MSCHAPv2 like error
77		 * reporting with EAP-GTC inside EAP-FAST tunnel. */
78		resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_GTC,
79				     0, EAP_CODE_RESPONSE, id);
80		return resp;
81	}
82
83	password = eap_get_config_otp(sm, &password_len);
84	if (password)
85		otp = 1;
86	else {
87		password = eap_get_config_password(sm, &password_len);
88		otp = 0;
89	}
90
91	if (password == NULL) {
92		wpa_printf(MSG_INFO, "EAP-GTC: Password not configured");
93		eap_sm_request_otp(sm, (const char *) pos, len);
94		ret->ignore = TRUE;
95		return NULL;
96	}
97
98	ret->ignore = FALSE;
99
100	ret->methodState = data->prefix ? METHOD_MAY_CONT : METHOD_DONE;
101	ret->decision = DECISION_COND_SUCC;
102	ret->allowNotifications = FALSE;
103
104	plen = password_len;
105	identity = eap_get_config_identity(sm, &identity_len);
106	if (identity == NULL)
107		return NULL;
108	if (data->prefix)
109		plen += 9 + identity_len + 1;
110	resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_GTC, plen,
111			     EAP_CODE_RESPONSE, id);
112	if (resp == NULL)
113		return NULL;
114	if (data->prefix) {
115		wpabuf_put_data(resp, "RESPONSE=", 9);
116		wpabuf_put_data(resp, identity, identity_len);
117		wpabuf_put_u8(resp, '\0');
118	}
119	wpabuf_put_data(resp, password, password_len);
120	wpa_hexdump_ascii_key(MSG_MSGDUMP, "EAP-GTC: Response",
121			      wpabuf_head_u8(resp) + sizeof(struct eap_hdr) +
122			      1, plen);
123
124	if (otp) {
125		wpa_printf(MSG_DEBUG, "EAP-GTC: Forgetting used password");
126		eap_clear_config_otp(sm);
127	}
128
129	return resp;
130}
131
132
133int eap_peer_gtc_register(void)
134{
135	struct eap_method *eap;
136	int ret;
137
138	eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
139				    EAP_VENDOR_IETF, EAP_TYPE_GTC, "GTC");
140	if (eap == NULL)
141		return -1;
142
143	eap->init = eap_gtc_init;
144	eap->deinit = eap_gtc_deinit;
145	eap->process = eap_gtc_process;
146
147	ret = eap_peer_method_register(eap);
148	if (ret)
149		eap_peer_method_free(eap);
150	return ret;
151}
152