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 
15 struct eap_gtc_data {
16 	int prefix;
17 };
18 
19 
20 static 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 
37 static 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 
44 static 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 
127 int eap_peer_gtc_register(void)
128 {
129 	struct eap_method *eap;
130 
131 	eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
132 				    EAP_VENDOR_IETF, EAP_TYPE_GTC, "GTC");
133 	if (eap == NULL)
134 		return -1;
135 
136 	eap->init = eap_gtc_init;
137 	eap->deinit = eap_gtc_deinit;
138 	eap->process = eap_gtc_process;
139 
140 	return eap_peer_method_register(eap);
141 }
142