1 /*
2  * EAP-WSC server for Wi-Fi Protected Setup
3  * Copyright (c) 2007-2008, 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 "eloop.h"
13 #include "eap_i.h"
14 #include "eap_common/eap_wsc_common.h"
15 #include "p2p/p2p.h"
16 #include "wps/wps.h"
17 
18 
19 struct eap_wsc_data {
20 	enum { START, MESG, FRAG_ACK, WAIT_FRAG_ACK, DONE, FAIL } state;
21 	int registrar;
22 	struct wpabuf *in_buf;
23 	struct wpabuf *out_buf;
24 	enum wsc_op_code in_op_code, out_op_code;
25 	size_t out_used;
26 	size_t fragment_size;
27 	struct wps_data *wps;
28 	int ext_reg_timeout;
29 };
30 
31 
32 #ifndef CONFIG_NO_STDOUT_DEBUG
eap_wsc_state_txt(int state)33 static const char * eap_wsc_state_txt(int state)
34 {
35 	switch (state) {
36 	case START:
37 		return "START";
38 	case MESG:
39 		return "MESG";
40 	case FRAG_ACK:
41 		return "FRAG_ACK";
42 	case WAIT_FRAG_ACK:
43 		return "WAIT_FRAG_ACK";
44 	case DONE:
45 		return "DONE";
46 	case FAIL:
47 		return "FAIL";
48 	default:
49 		return "?";
50 	}
51 }
52 #endif /* CONFIG_NO_STDOUT_DEBUG */
53 
54 
eap_wsc_state(struct eap_wsc_data * data,int state)55 static void eap_wsc_state(struct eap_wsc_data *data, int state)
56 {
57 	wpa_printf(MSG_DEBUG, "EAP-WSC: %s -> %s",
58 		   eap_wsc_state_txt(data->state),
59 		   eap_wsc_state_txt(state));
60 	data->state = state;
61 }
62 
63 
eap_wsc_ext_reg_timeout(void * eloop_ctx,void * timeout_ctx)64 static void eap_wsc_ext_reg_timeout(void *eloop_ctx, void *timeout_ctx)
65 {
66 	struct eap_sm *sm = eloop_ctx;
67 	struct eap_wsc_data *data = timeout_ctx;
68 
69 	if (sm->method_pending != METHOD_PENDING_WAIT)
70 		return;
71 
72 	wpa_printf(MSG_DEBUG, "EAP-WSC: Timeout while waiting for an External "
73 		   "Registrar");
74 	data->ext_reg_timeout = 1;
75 	eap_sm_pending_cb(sm);
76 }
77 
78 
eap_wsc_init(struct eap_sm * sm)79 static void * eap_wsc_init(struct eap_sm *sm)
80 {
81 	struct eap_wsc_data *data;
82 	int registrar;
83 	struct wps_config cfg;
84 
85 	if (sm->identity && sm->identity_len == WSC_ID_REGISTRAR_LEN &&
86 	    os_memcmp(sm->identity, WSC_ID_REGISTRAR, WSC_ID_REGISTRAR_LEN) ==
87 	    0)
88 		registrar = 0; /* Supplicant is Registrar */
89 	else if (sm->identity && sm->identity_len == WSC_ID_ENROLLEE_LEN &&
90 		 os_memcmp(sm->identity, WSC_ID_ENROLLEE, WSC_ID_ENROLLEE_LEN)
91 		 == 0)
92 		registrar = 1; /* Supplicant is Enrollee */
93 	else {
94 		wpa_hexdump_ascii(MSG_INFO, "EAP-WSC: Unexpected identity",
95 				  sm->identity, sm->identity_len);
96 		return NULL;
97 	}
98 
99 	data = os_zalloc(sizeof(*data));
100 	if (data == NULL)
101 		return NULL;
102 	data->state = registrar ? START : MESG;
103 	data->registrar = registrar;
104 
105 	os_memset(&cfg, 0, sizeof(cfg));
106 	cfg.wps = sm->wps;
107 	cfg.registrar = registrar;
108 	if (registrar) {
109 		if (sm->wps == NULL || sm->wps->registrar == NULL) {
110 			wpa_printf(MSG_INFO, "EAP-WSC: WPS Registrar not "
111 				   "initialized");
112 			os_free(data);
113 			return NULL;
114 		}
115 	} else {
116 		if (sm->user == NULL || sm->user->password == NULL) {
117 			/*
118 			 * In theory, this should not really be needed, but
119 			 * Windows 7 uses Registrar mode to probe AP's WPS
120 			 * capabilities before trying to use Enrollee and fails
121 			 * if the AP does not allow that probing to happen..
122 			 */
123 			wpa_printf(MSG_DEBUG, "EAP-WSC: No AP PIN (password) "
124 				   "configured for Enrollee functionality - "
125 				   "allow for probing capabilities (M1)");
126 		} else {
127 			cfg.pin = sm->user->password;
128 			cfg.pin_len = sm->user->password_len;
129 		}
130 	}
131 	cfg.assoc_wps_ie = sm->assoc_wps_ie;
132 	cfg.peer_addr = sm->peer_addr;
133 #ifdef CONFIG_P2P
134 	if (sm->assoc_p2p_ie) {
135 		wpa_printf(MSG_DEBUG, "EAP-WSC: Prefer PSK format for P2P "
136 			   "client");
137 		cfg.use_psk_key = 1;
138 		cfg.p2p_dev_addr = p2p_get_go_dev_addr(sm->assoc_p2p_ie);
139 	}
140 #endif /* CONFIG_P2P */
141 	cfg.pbc_in_m1 = sm->pbc_in_m1;
142 	data->wps = wps_init(&cfg);
143 	if (data->wps == NULL) {
144 		os_free(data);
145 		return NULL;
146 	}
147 	data->fragment_size = sm->fragment_size > 0 ? sm->fragment_size :
148 		WSC_FRAGMENT_SIZE;
149 
150 	return data;
151 }
152 
153 
eap_wsc_reset(struct eap_sm * sm,void * priv)154 static void eap_wsc_reset(struct eap_sm *sm, void *priv)
155 {
156 	struct eap_wsc_data *data = priv;
157 	eloop_cancel_timeout(eap_wsc_ext_reg_timeout, sm, data);
158 	wpabuf_free(data->in_buf);
159 	wpabuf_free(data->out_buf);
160 	wps_deinit(data->wps);
161 	os_free(data);
162 }
163 
164 
eap_wsc_build_start(struct eap_sm * sm,struct eap_wsc_data * data,u8 id)165 static struct wpabuf * eap_wsc_build_start(struct eap_sm *sm,
166 					   struct eap_wsc_data *data, u8 id)
167 {
168 	struct wpabuf *req;
169 
170 	req = eap_msg_alloc(EAP_VENDOR_WFA, EAP_VENDOR_TYPE_WSC, 2,
171 			    EAP_CODE_REQUEST, id);
172 	if (req == NULL) {
173 		wpa_printf(MSG_ERROR, "EAP-WSC: Failed to allocate memory for "
174 			   "request");
175 		return NULL;
176 	}
177 
178 	wpa_printf(MSG_DEBUG, "EAP-WSC: Send WSC/Start");
179 	wpabuf_put_u8(req, WSC_Start); /* Op-Code */
180 	wpabuf_put_u8(req, 0); /* Flags */
181 
182 	return req;
183 }
184 
185 
eap_wsc_build_msg(struct eap_wsc_data * data,u8 id)186 static struct wpabuf * eap_wsc_build_msg(struct eap_wsc_data *data, u8 id)
187 {
188 	struct wpabuf *req;
189 	u8 flags;
190 	size_t send_len, plen;
191 
192 	flags = 0;
193 	send_len = wpabuf_len(data->out_buf) - data->out_used;
194 	if (2 + send_len > data->fragment_size) {
195 		send_len = data->fragment_size - 2;
196 		flags |= WSC_FLAGS_MF;
197 		if (data->out_used == 0) {
198 			flags |= WSC_FLAGS_LF;
199 			send_len -= 2;
200 		}
201 	}
202 	plen = 2 + send_len;
203 	if (flags & WSC_FLAGS_LF)
204 		plen += 2;
205 	req = eap_msg_alloc(EAP_VENDOR_WFA, EAP_VENDOR_TYPE_WSC, plen,
206 			    EAP_CODE_REQUEST, id);
207 	if (req == NULL) {
208 		wpa_printf(MSG_ERROR, "EAP-WSC: Failed to allocate memory for "
209 			   "request");
210 		return NULL;
211 	}
212 
213 	wpabuf_put_u8(req, data->out_op_code); /* Op-Code */
214 	wpabuf_put_u8(req, flags); /* Flags */
215 	if (flags & WSC_FLAGS_LF)
216 		wpabuf_put_be16(req, wpabuf_len(data->out_buf));
217 
218 	wpabuf_put_data(req, wpabuf_head_u8(data->out_buf) + data->out_used,
219 			send_len);
220 	data->out_used += send_len;
221 
222 	if (data->out_used == wpabuf_len(data->out_buf)) {
223 		wpa_printf(MSG_DEBUG, "EAP-WSC: Sending out %lu bytes "
224 			   "(message sent completely)",
225 			   (unsigned long) send_len);
226 		wpabuf_free(data->out_buf);
227 		data->out_buf = NULL;
228 		data->out_used = 0;
229 		eap_wsc_state(data, MESG);
230 	} else {
231 		wpa_printf(MSG_DEBUG, "EAP-WSC: Sending out %lu bytes "
232 			   "(%lu more to send)", (unsigned long) send_len,
233 			   (unsigned long) wpabuf_len(data->out_buf) -
234 			   data->out_used);
235 		eap_wsc_state(data, WAIT_FRAG_ACK);
236 	}
237 
238 	return req;
239 }
240 
241 
eap_wsc_buildReq(struct eap_sm * sm,void * priv,u8 id)242 static struct wpabuf * eap_wsc_buildReq(struct eap_sm *sm, void *priv, u8 id)
243 {
244 	struct eap_wsc_data *data = priv;
245 
246 	switch (data->state) {
247 	case START:
248 		return eap_wsc_build_start(sm, data, id);
249 	case MESG:
250 		if (data->out_buf == NULL) {
251 			data->out_buf = wps_get_msg(data->wps,
252 						    &data->out_op_code);
253 			if (data->out_buf == NULL) {
254 				wpa_printf(MSG_DEBUG, "EAP-WSC: Failed to "
255 					   "receive message from WPS");
256 				return NULL;
257 			}
258 			data->out_used = 0;
259 		}
260 		/* fall through */
261 	case WAIT_FRAG_ACK:
262 		return eap_wsc_build_msg(data, id);
263 	case FRAG_ACK:
264 		return eap_wsc_build_frag_ack(id, EAP_CODE_REQUEST);
265 	default:
266 		wpa_printf(MSG_DEBUG, "EAP-WSC: Unexpected state %d in "
267 			   "buildReq", data->state);
268 		return NULL;
269 	}
270 }
271 
272 
eap_wsc_check(struct eap_sm * sm,void * priv,struct wpabuf * respData)273 static Boolean eap_wsc_check(struct eap_sm *sm, void *priv,
274 			     struct wpabuf *respData)
275 {
276 	const u8 *pos;
277 	size_t len;
278 
279 	pos = eap_hdr_validate(EAP_VENDOR_WFA, EAP_VENDOR_TYPE_WSC,
280 			       respData, &len);
281 	if (pos == NULL || len < 2) {
282 		wpa_printf(MSG_INFO, "EAP-WSC: Invalid frame");
283 		return TRUE;
284 	}
285 
286 	return FALSE;
287 }
288 
289 
eap_wsc_process_cont(struct eap_wsc_data * data,const u8 * buf,size_t len,u8 op_code)290 static int eap_wsc_process_cont(struct eap_wsc_data *data,
291 				const u8 *buf, size_t len, u8 op_code)
292 {
293 	/* Process continuation of a pending message */
294 	if (op_code != data->in_op_code) {
295 		wpa_printf(MSG_DEBUG, "EAP-WSC: Unexpected Op-Code %d in "
296 			   "fragment (expected %d)",
297 			   op_code, data->in_op_code);
298 		eap_wsc_state(data, FAIL);
299 		return -1;
300 	}
301 
302 	if (len > wpabuf_tailroom(data->in_buf)) {
303 		wpa_printf(MSG_DEBUG, "EAP-WSC: Fragment overflow");
304 		eap_wsc_state(data, FAIL);
305 		return -1;
306 	}
307 
308 	wpabuf_put_data(data->in_buf, buf, len);
309 	wpa_printf(MSG_DEBUG, "EAP-WSC: Received %lu bytes, waiting for %lu "
310 		   "bytes more", (unsigned long) len,
311 		   (unsigned long) wpabuf_tailroom(data->in_buf));
312 
313 	return 0;
314 }
315 
316 
eap_wsc_process_fragment(struct eap_wsc_data * data,u8 flags,u8 op_code,u16 message_length,const u8 * buf,size_t len)317 static int eap_wsc_process_fragment(struct eap_wsc_data *data,
318 				    u8 flags, u8 op_code, u16 message_length,
319 				    const u8 *buf, size_t len)
320 {
321 	/* Process a fragment that is not the last one of the message */
322 	if (data->in_buf == NULL && !(flags & WSC_FLAGS_LF)) {
323 		wpa_printf(MSG_DEBUG, "EAP-WSC: No Message Length "
324 			   "field in a fragmented packet");
325 		return -1;
326 	}
327 
328 	if (data->in_buf == NULL) {
329 		/* First fragment of the message */
330 		data->in_buf = wpabuf_alloc(message_length);
331 		if (data->in_buf == NULL) {
332 			wpa_printf(MSG_DEBUG, "EAP-WSC: No memory for "
333 				   "message");
334 			return -1;
335 		}
336 		data->in_op_code = op_code;
337 		wpabuf_put_data(data->in_buf, buf, len);
338 		wpa_printf(MSG_DEBUG, "EAP-WSC: Received %lu bytes in "
339 			   "first fragment, waiting for %lu bytes more",
340 			   (unsigned long) len,
341 			   (unsigned long) wpabuf_tailroom(data->in_buf));
342 	}
343 
344 	return 0;
345 }
346 
347 
eap_wsc_process(struct eap_sm * sm,void * priv,struct wpabuf * respData)348 static void eap_wsc_process(struct eap_sm *sm, void *priv,
349 			    struct wpabuf *respData)
350 {
351 	struct eap_wsc_data *data = priv;
352 	const u8 *start, *pos, *end;
353 	size_t len;
354 	u8 op_code, flags;
355 	u16 message_length = 0;
356 	enum wps_process_res res;
357 	struct wpabuf tmpbuf;
358 
359 	eloop_cancel_timeout(eap_wsc_ext_reg_timeout, sm, data);
360 	if (data->ext_reg_timeout) {
361 		eap_wsc_state(data, FAIL);
362 		return;
363 	}
364 
365 	pos = eap_hdr_validate(EAP_VENDOR_WFA, EAP_VENDOR_TYPE_WSC,
366 			       respData, &len);
367 	if (pos == NULL || len < 2)
368 		return; /* Should not happen; message already verified */
369 
370 	start = pos;
371 	end = start + len;
372 
373 	op_code = *pos++;
374 	flags = *pos++;
375 	if (flags & WSC_FLAGS_LF) {
376 		if (end - pos < 2) {
377 			wpa_printf(MSG_DEBUG, "EAP-WSC: Message underflow");
378 			return;
379 		}
380 		message_length = WPA_GET_BE16(pos);
381 		pos += 2;
382 
383 		if (message_length < end - pos || message_length > 50000) {
384 			wpa_printf(MSG_DEBUG, "EAP-WSC: Invalid Message "
385 				   "Length");
386 			return;
387 		}
388 	}
389 
390 	wpa_printf(MSG_DEBUG, "EAP-WSC: Received packet: Op-Code %d "
391 		   "Flags 0x%x Message Length %d",
392 		   op_code, flags, message_length);
393 
394 	if (data->state == WAIT_FRAG_ACK) {
395 		if (op_code != WSC_FRAG_ACK) {
396 			wpa_printf(MSG_DEBUG, "EAP-WSC: Unexpected Op-Code %d "
397 				   "in WAIT_FRAG_ACK state", op_code);
398 			eap_wsc_state(data, FAIL);
399 			return;
400 		}
401 		wpa_printf(MSG_DEBUG, "EAP-WSC: Fragment acknowledged");
402 		eap_wsc_state(data, MESG);
403 		return;
404 	}
405 
406 	if (op_code != WSC_ACK && op_code != WSC_NACK && op_code != WSC_MSG &&
407 	    op_code != WSC_Done) {
408 		wpa_printf(MSG_DEBUG, "EAP-WSC: Unexpected Op-Code %d",
409 			   op_code);
410 		eap_wsc_state(data, FAIL);
411 		return;
412 	}
413 
414 	if (data->in_buf &&
415 	    eap_wsc_process_cont(data, pos, end - pos, op_code) < 0) {
416 		eap_wsc_state(data, FAIL);
417 		return;
418 	}
419 
420 	if (flags & WSC_FLAGS_MF) {
421 		if (eap_wsc_process_fragment(data, flags, op_code,
422 					     message_length, pos, end - pos) <
423 		    0)
424 			eap_wsc_state(data, FAIL);
425 		else
426 			eap_wsc_state(data, FRAG_ACK);
427 		return;
428 	}
429 
430 	if (data->in_buf == NULL) {
431 		/* Wrap unfragmented messages as wpabuf without extra copy */
432 		wpabuf_set(&tmpbuf, pos, end - pos);
433 		data->in_buf = &tmpbuf;
434 	}
435 
436 	res = wps_process_msg(data->wps, op_code, data->in_buf);
437 	switch (res) {
438 	case WPS_DONE:
439 		wpa_printf(MSG_DEBUG, "EAP-WSC: WPS processing completed "
440 			   "successfully - report EAP failure");
441 		eap_wsc_state(data, FAIL);
442 		break;
443 	case WPS_CONTINUE:
444 		eap_wsc_state(data, MESG);
445 		break;
446 	case WPS_FAILURE:
447 		wpa_printf(MSG_DEBUG, "EAP-WSC: WPS processing failed");
448 		eap_wsc_state(data, FAIL);
449 		break;
450 	case WPS_PENDING:
451 		eap_wsc_state(data, MESG);
452 		sm->method_pending = METHOD_PENDING_WAIT;
453 		eloop_cancel_timeout(eap_wsc_ext_reg_timeout, sm, data);
454 		eloop_register_timeout(5, 0, eap_wsc_ext_reg_timeout,
455 				       sm, data);
456 		break;
457 	}
458 
459 	if (data->in_buf != &tmpbuf)
460 		wpabuf_free(data->in_buf);
461 	data->in_buf = NULL;
462 }
463 
464 
eap_wsc_isDone(struct eap_sm * sm,void * priv)465 static Boolean eap_wsc_isDone(struct eap_sm *sm, void *priv)
466 {
467 	struct eap_wsc_data *data = priv;
468 	return data->state == FAIL;
469 }
470 
471 
eap_wsc_isSuccess(struct eap_sm * sm,void * priv)472 static Boolean eap_wsc_isSuccess(struct eap_sm *sm, void *priv)
473 {
474 	/* EAP-WSC will always result in EAP-Failure */
475 	return FALSE;
476 }
477 
478 
eap_wsc_getTimeout(struct eap_sm * sm,void * priv)479 static int eap_wsc_getTimeout(struct eap_sm *sm, void *priv)
480 {
481 	/* Recommended retransmit times: retransmit timeout 5 seconds,
482 	 * per-message timeout 15 seconds, i.e., 3 tries. */
483 	sm->MaxRetrans = 2; /* total 3 attempts */
484 	return 5;
485 }
486 
487 
eap_server_wsc_register(void)488 int eap_server_wsc_register(void)
489 {
490 	struct eap_method *eap;
491 
492 	eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION,
493 				      EAP_VENDOR_WFA, EAP_VENDOR_TYPE_WSC,
494 				      "WSC");
495 	if (eap == NULL)
496 		return -1;
497 
498 	eap->init = eap_wsc_init;
499 	eap->reset = eap_wsc_reset;
500 	eap->buildReq = eap_wsc_buildReq;
501 	eap->check = eap_wsc_check;
502 	eap->process = eap_wsc_process;
503 	eap->isDone = eap_wsc_isDone;
504 	eap->isSuccess = eap_wsc_isSuccess;
505 	eap->getTimeout = eap_wsc_getTimeout;
506 
507 	return eap_server_method_register(eap);
508 }
509