1/*
2 * EAP peer method: EAP-GTC (RFC 3748)
3 * Copyright (c) 2004-2006, Jouni Malinen <j@w1.fi>
4 *
5 * This software may be distributed under the terms of the BSD license.
6 * See README for more details.
7 */
8
9#include "includes.h"
10
11#include "common.h"
12#include "eap_i.h"
13
14
15struct eap_gtc_data {
16	int prefix;
17};
18
19
20static void * eap_gtc_init(struct eap_sm *sm)
21{
22	struct eap_gtc_data *data;
23	data = os_zalloc(sizeof(*data));
24	if (data == NULL)
25		return NULL;
26
27	if (sm->m && sm->m->vendor == EAP_VENDOR_IETF &&
28	    sm->m->method == EAP_TYPE_FAST) {
29		wpa_printf(MSG_DEBUG, "EAP-GTC: EAP-FAST tunnel - use prefix "
30			   "with challenge/response");
31		data->prefix = 1;
32	}
33	return data;
34}
35
36
37static void eap_gtc_deinit(struct eap_sm *sm, void *priv)
38{
39	struct eap_gtc_data *data = priv;
40	os_free(data);
41}
42
43
44static struct wpabuf * eap_gtc_process(struct eap_sm *sm, void *priv,
45				       struct eap_method_ret *ret,
46				       const struct wpabuf *reqData)
47{
48	struct eap_gtc_data *data = priv;
49	struct wpabuf *resp;
50	const u8 *pos, *password, *identity;
51	size_t password_len, identity_len, len, plen;
52	int otp;
53	u8 id;
54
55	pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_GTC, reqData, &len);
56	if (pos == NULL) {
57		ret->ignore = TRUE;
58		return NULL;
59	}
60	id = eap_get_id(reqData);
61
62	wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-GTC: Request message", pos, len);
63	if (data->prefix &&
64	    (len < 10 || os_memcmp(pos, "CHALLENGE=", 10) != 0)) {
65		wpa_printf(MSG_DEBUG, "EAP-GTC: Challenge did not start with "
66			   "expected prefix");
67
68		/* Send an empty response in order to allow tunneled
69		 * acknowledgement of the failure. This will also cover the
70		 * error case which seems to use EAP-MSCHAPv2 like error
71		 * reporting with EAP-GTC inside EAP-FAST tunnel. */
72		resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_GTC,
73				     0, EAP_CODE_RESPONSE, id);
74		return resp;
75	}
76
77	password = eap_get_config_otp(sm, &password_len);
78	if (password)
79		otp = 1;
80	else {
81		password = eap_get_config_password(sm, &password_len);
82		otp = 0;
83	}
84
85	if (password == NULL) {
86		wpa_printf(MSG_INFO, "EAP-GTC: Password not configured");
87		eap_sm_request_otp(sm, (const char *) pos, len);
88		ret->ignore = TRUE;
89		return NULL;
90	}
91
92	ret->ignore = FALSE;
93
94	ret->methodState = data->prefix ? METHOD_MAY_CONT : METHOD_DONE;
95	ret->decision = DECISION_COND_SUCC;
96	ret->allowNotifications = FALSE;
97
98	plen = password_len;
99	identity = eap_get_config_identity(sm, &identity_len);
100	if (identity == NULL)
101		return NULL;
102	if (data->prefix)
103		plen += 9 + identity_len + 1;
104	resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_GTC, plen,
105			     EAP_CODE_RESPONSE, id);
106	if (resp == NULL)
107		return NULL;
108	if (data->prefix) {
109		wpabuf_put_data(resp, "RESPONSE=", 9);
110		wpabuf_put_data(resp, identity, identity_len);
111		wpabuf_put_u8(resp, '\0');
112	}
113	wpabuf_put_data(resp, password, password_len);
114	wpa_hexdump_ascii_key(MSG_MSGDUMP, "EAP-GTC: Response",
115			      wpabuf_head_u8(resp) + sizeof(struct eap_hdr) +
116			      1, plen);
117
118	if (otp) {
119		wpa_printf(MSG_DEBUG, "EAP-GTC: Forgetting used password");
120		eap_clear_config_otp(sm);
121	}
122
123	return resp;
124}
125
126
127int eap_peer_gtc_register(void)
128{
129	struct eap_method *eap;
130	int ret;
131
132	eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
133				    EAP_VENDOR_IETF, EAP_TYPE_GTC, "GTC");
134	if (eap == NULL)
135		return -1;
136
137	eap->init = eap_gtc_init;
138	eap->deinit = eap_gtc_deinit;
139	eap->process = eap_gtc_process;
140
141	ret = eap_peer_method_register(eap);
142	if (ret)
143		eap_peer_method_free(eap);
144	return ret;
145}
146