1 /*
2  * hostapd / EAP-TLS (RFC 2716)
3  * Copyright (c) 2004-2008, 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 #include "eap_tls_common.h"
14 #include "crypto/tls.h"
15 
16 
17 static void eap_tls_reset(struct eap_sm *sm, void *priv);
18 
19 
20 struct eap_tls_data {
21 	struct eap_ssl_data ssl;
22 	enum { START, CONTINUE, SUCCESS, FAILURE } state;
23 	int established;
24 	u8 eap_type;
25 };
26 
27 
28 static const char * eap_tls_state_txt(int state)
29 {
30 	switch (state) {
31 	case START:
32 		return "START";
33 	case CONTINUE:
34 		return "CONTINUE";
35 	case SUCCESS:
36 		return "SUCCESS";
37 	case FAILURE:
38 		return "FAILURE";
39 	default:
40 		return "Unknown?!";
41 	}
42 }
43 
44 
45 static void eap_tls_state(struct eap_tls_data *data, int state)
46 {
47 	wpa_printf(MSG_DEBUG, "EAP-TLS: %s -> %s",
48 		   eap_tls_state_txt(data->state),
49 		   eap_tls_state_txt(state));
50 	data->state = state;
51 }
52 
53 
54 static void * eap_tls_init(struct eap_sm *sm)
55 {
56 	struct eap_tls_data *data;
57 
58 	data = os_zalloc(sizeof(*data));
59 	if (data == NULL)
60 		return NULL;
61 	data->state = START;
62 
63 	if (eap_server_tls_ssl_init(sm, &data->ssl, 1)) {
64 		wpa_printf(MSG_INFO, "EAP-TLS: Failed to initialize SSL.");
65 		eap_tls_reset(sm, data);
66 		return NULL;
67 	}
68 
69 	data->eap_type = EAP_TYPE_TLS;
70 
71 	return data;
72 }
73 
74 
75 #ifdef EAP_SERVER_UNAUTH_TLS
76 static void * eap_unauth_tls_init(struct eap_sm *sm)
77 {
78 	struct eap_tls_data *data;
79 
80 	data = os_zalloc(sizeof(*data));
81 	if (data == NULL)
82 		return NULL;
83 	data->state = START;
84 
85 	if (eap_server_tls_ssl_init(sm, &data->ssl, 0)) {
86 		wpa_printf(MSG_INFO, "EAP-TLS: Failed to initialize SSL.");
87 		eap_tls_reset(sm, data);
88 		return NULL;
89 	}
90 
91 	data->eap_type = EAP_UNAUTH_TLS_TYPE;
92 	return data;
93 }
94 #endif /* EAP_SERVER_UNAUTH_TLS */
95 
96 
97 static void eap_tls_reset(struct eap_sm *sm, void *priv)
98 {
99 	struct eap_tls_data *data = priv;
100 	if (data == NULL)
101 		return;
102 	eap_server_tls_ssl_deinit(sm, &data->ssl);
103 	os_free(data);
104 }
105 
106 
107 static struct wpabuf * eap_tls_build_start(struct eap_sm *sm,
108 					   struct eap_tls_data *data, u8 id)
109 {
110 	struct wpabuf *req;
111 
112 	req = eap_tls_msg_alloc(data->eap_type, 1, EAP_CODE_REQUEST, id);
113 	if (req == NULL) {
114 		wpa_printf(MSG_ERROR, "EAP-TLS: Failed to allocate memory for "
115 			   "request");
116 		eap_tls_state(data, FAILURE);
117 		return NULL;
118 	}
119 
120 	wpabuf_put_u8(req, EAP_TLS_FLAGS_START);
121 
122 	eap_tls_state(data, CONTINUE);
123 
124 	return req;
125 }
126 
127 
128 static struct wpabuf * eap_tls_buildReq(struct eap_sm *sm, void *priv, u8 id)
129 {
130 	struct eap_tls_data *data = priv;
131 	struct wpabuf *res;
132 
133 	if (data->ssl.state == FRAG_ACK) {
134 		return eap_server_tls_build_ack(id, data->eap_type, 0);
135 	}
136 
137 	if (data->ssl.state == WAIT_FRAG_ACK) {
138 		res = eap_server_tls_build_msg(&data->ssl, data->eap_type, 0,
139 					       id);
140 		goto check_established;
141 	}
142 
143 	switch (data->state) {
144 	case START:
145 		return eap_tls_build_start(sm, data, id);
146 	case CONTINUE:
147 		if (tls_connection_established(sm->ssl_ctx, data->ssl.conn))
148 			data->established = 1;
149 		break;
150 	default:
151 		wpa_printf(MSG_DEBUG, "EAP-TLS: %s - unexpected state %d",
152 			   __func__, data->state);
153 		return NULL;
154 	}
155 
156 	res = eap_server_tls_build_msg(&data->ssl, data->eap_type, 0, id);
157 
158 check_established:
159 	if (data->established && data->ssl.state != WAIT_FRAG_ACK) {
160 		/* TLS handshake has been completed and there are no more
161 		 * fragments waiting to be sent out. */
162 		wpa_printf(MSG_DEBUG, "EAP-TLS: Done");
163 		eap_tls_state(data, SUCCESS);
164 	}
165 
166 	return res;
167 }
168 
169 
170 static Boolean eap_tls_check(struct eap_sm *sm, void *priv,
171 			     struct wpabuf *respData)
172 {
173 	struct eap_tls_data *data = priv;
174 	const u8 *pos;
175 	size_t len;
176 
177 	if (data->eap_type == EAP_UNAUTH_TLS_TYPE)
178 		pos = eap_hdr_validate(EAP_VENDOR_UNAUTH_TLS,
179 				       EAP_VENDOR_TYPE_UNAUTH_TLS, respData,
180 				       &len);
181 	else
182 		pos = eap_hdr_validate(EAP_VENDOR_IETF, data->eap_type,
183 				       respData, &len);
184 	if (pos == NULL || len < 1) {
185 		wpa_printf(MSG_INFO, "EAP-TLS: Invalid frame");
186 		return TRUE;
187 	}
188 
189 	return FALSE;
190 }
191 
192 
193 static void eap_tls_process_msg(struct eap_sm *sm, void *priv,
194 				const struct wpabuf *respData)
195 {
196 	struct eap_tls_data *data = priv;
197 	if (data->state == SUCCESS && wpabuf_len(data->ssl.tls_in) == 0) {
198 		wpa_printf(MSG_DEBUG, "EAP-TLS: Client acknowledged final TLS "
199 			   "handshake message");
200 		return;
201 	}
202 	if (eap_server_tls_phase1(sm, &data->ssl) < 0)
203 		eap_tls_state(data, FAILURE);
204 }
205 
206 
207 static void eap_tls_process(struct eap_sm *sm, void *priv,
208 			    struct wpabuf *respData)
209 {
210 	struct eap_tls_data *data = priv;
211 	if (eap_server_tls_process(sm, &data->ssl, respData, data,
212 				   data->eap_type, NULL, eap_tls_process_msg) <
213 	    0)
214 		eap_tls_state(data, FAILURE);
215 }
216 
217 
218 static Boolean eap_tls_isDone(struct eap_sm *sm, void *priv)
219 {
220 	struct eap_tls_data *data = priv;
221 	return data->state == SUCCESS || data->state == FAILURE;
222 }
223 
224 
225 static u8 * eap_tls_getKey(struct eap_sm *sm, void *priv, size_t *len)
226 {
227 	struct eap_tls_data *data = priv;
228 	u8 *eapKeyData;
229 
230 	if (data->state != SUCCESS)
231 		return NULL;
232 
233 	eapKeyData = eap_server_tls_derive_key(sm, &data->ssl,
234 					       "client EAP encryption",
235 					       EAP_TLS_KEY_LEN);
236 	if (eapKeyData) {
237 		*len = EAP_TLS_KEY_LEN;
238 		wpa_hexdump(MSG_DEBUG, "EAP-TLS: Derived key",
239 			    eapKeyData, EAP_TLS_KEY_LEN);
240 	} else {
241 		wpa_printf(MSG_DEBUG, "EAP-TLS: Failed to derive key");
242 	}
243 
244 	return eapKeyData;
245 }
246 
247 
248 static u8 * eap_tls_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
249 {
250 	struct eap_tls_data *data = priv;
251 	u8 *eapKeyData, *emsk;
252 
253 	if (data->state != SUCCESS)
254 		return NULL;
255 
256 	eapKeyData = eap_server_tls_derive_key(sm, &data->ssl,
257 					       "client EAP encryption",
258 					       EAP_TLS_KEY_LEN + EAP_EMSK_LEN);
259 	if (eapKeyData) {
260 		emsk = os_malloc(EAP_EMSK_LEN);
261 		if (emsk)
262 			os_memcpy(emsk, eapKeyData + EAP_TLS_KEY_LEN,
263 				  EAP_EMSK_LEN);
264 		os_free(eapKeyData);
265 	} else
266 		emsk = NULL;
267 
268 	if (emsk) {
269 		*len = EAP_EMSK_LEN;
270 		wpa_hexdump(MSG_DEBUG, "EAP-TLS: Derived EMSK",
271 			    emsk, EAP_EMSK_LEN);
272 	} else {
273 		wpa_printf(MSG_DEBUG, "EAP-TLS: Failed to derive EMSK");
274 	}
275 
276 	return emsk;
277 }
278 
279 
280 static Boolean eap_tls_isSuccess(struct eap_sm *sm, void *priv)
281 {
282 	struct eap_tls_data *data = priv;
283 	return data->state == SUCCESS;
284 }
285 
286 
287 int eap_server_tls_register(void)
288 {
289 	struct eap_method *eap;
290 	int ret;
291 
292 	eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION,
293 				      EAP_VENDOR_IETF, EAP_TYPE_TLS, "TLS");
294 	if (eap == NULL)
295 		return -1;
296 
297 	eap->init = eap_tls_init;
298 	eap->reset = eap_tls_reset;
299 	eap->buildReq = eap_tls_buildReq;
300 	eap->check = eap_tls_check;
301 	eap->process = eap_tls_process;
302 	eap->isDone = eap_tls_isDone;
303 	eap->getKey = eap_tls_getKey;
304 	eap->isSuccess = eap_tls_isSuccess;
305 	eap->get_emsk = eap_tls_get_emsk;
306 
307 	ret = eap_server_method_register(eap);
308 	if (ret)
309 		eap_server_method_free(eap);
310 	return ret;
311 }
312 
313 
314 #ifdef EAP_SERVER_UNAUTH_TLS
315 int eap_server_unauth_tls_register(void)
316 {
317 	struct eap_method *eap;
318 	int ret;
319 
320 	eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION,
321 				      EAP_VENDOR_UNAUTH_TLS,
322 				      EAP_VENDOR_TYPE_UNAUTH_TLS,
323 				      "UNAUTH-TLS");
324 	if (eap == NULL)
325 		return -1;
326 
327 	eap->init = eap_unauth_tls_init;
328 	eap->reset = eap_tls_reset;
329 	eap->buildReq = eap_tls_buildReq;
330 	eap->check = eap_tls_check;
331 	eap->process = eap_tls_process;
332 	eap->isDone = eap_tls_isDone;
333 	eap->getKey = eap_tls_getKey;
334 	eap->isSuccess = eap_tls_isSuccess;
335 	eap->get_emsk = eap_tls_get_emsk;
336 
337 	ret = eap_server_method_register(eap);
338 	if (ret)
339 		eap_server_method_free(eap);
340 	return ret;
341 }
342 #endif /* EAP_SERVER_UNAUTH_TLS */
343