eap_server_wsc.c revision 214501 
1/*
2 * EAP-WSC server for Wi-Fi Protected Setup
3 * Copyright (c) 2007-2008, 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 "eloop.h"
19#include "eap_i.h"
20#include "eap_common/eap_wsc_common.h"
21#include "wps/wps.h"
22
23
24struct eap_wsc_data {
25	enum { START, MESG, FRAG_ACK, WAIT_FRAG_ACK, DONE, FAIL } state;
26	int registrar;
27	struct wpabuf *in_buf;
28	struct wpabuf *out_buf;
29	enum wsc_op_code in_op_code, out_op_code;
30	size_t out_used;
31	size_t fragment_size;
32	struct wps_data *wps;
33	int ext_reg_timeout;
34};
35
36
37#ifndef CONFIG_NO_STDOUT_DEBUG
38static const char * eap_wsc_state_txt(int state)
39{
40	switch (state) {
41	case START:
42		return "START";
43	case MESG:
44		return "MESG";
45	case FRAG_ACK:
46		return "FRAG_ACK";
47	case WAIT_FRAG_ACK:
48		return "WAIT_FRAG_ACK";
49	case DONE:
50		return "DONE";
51	case FAIL:
52		return "FAIL";
53	default:
54		return "?";
55	}
56}
57#endif /* CONFIG_NO_STDOUT_DEBUG */
58
59
60static void eap_wsc_state(struct eap_wsc_data *data, int state)
61{
62	wpa_printf(MSG_DEBUG, "EAP-WSC: %s -> %s",
63		   eap_wsc_state_txt(data->state),
64		   eap_wsc_state_txt(state));
65	data->state = state;
66}
67
68
69static void eap_wsc_ext_reg_timeout(void *eloop_ctx, void *timeout_ctx)
70{
71	struct eap_sm *sm = eloop_ctx;
72	struct eap_wsc_data *data = timeout_ctx;
73
74	if (sm->method_pending != METHOD_PENDING_WAIT)
75		return;
76
77	wpa_printf(MSG_DEBUG, "EAP-WSC: Timeout while waiting for an External "
78		   "Registrar");
79	data->ext_reg_timeout = 1;
80	eap_sm_pending_cb(sm);
81}
82
83
84static void * eap_wsc_init(struct eap_sm *sm)
85{
86	struct eap_wsc_data *data;
87	int registrar;
88	struct wps_config cfg;
89
90	if (sm->identity && sm->identity_len == WSC_ID_REGISTRAR_LEN &&
91	    os_memcmp(sm->identity, WSC_ID_REGISTRAR, WSC_ID_REGISTRAR_LEN) ==
92	    0)
93		registrar = 0; /* Supplicant is Registrar */
94	else if (sm->identity && sm->identity_len == WSC_ID_ENROLLEE_LEN &&
95		 os_memcmp(sm->identity, WSC_ID_ENROLLEE, WSC_ID_ENROLLEE_LEN)
96		 == 0)
97		registrar = 1; /* Supplicant is Enrollee */
98	else {
99		wpa_hexdump_ascii(MSG_INFO, "EAP-WSC: Unexpected identity",
100				  sm->identity, sm->identity_len);
101		return NULL;
102	}
103
104	data = os_zalloc(sizeof(*data));
105	if (data == NULL)
106		return NULL;
107	data->state = registrar ? START : MESG;
108	data->registrar = registrar;
109
110	os_memset(&cfg, 0, sizeof(cfg));
111	cfg.wps = sm->wps;
112	cfg.registrar = registrar;
113	if (registrar) {
114		if (sm->wps == NULL || sm->wps->registrar == NULL) {
115			wpa_printf(MSG_INFO, "EAP-WSC: WPS Registrar not "
116				   "initialized");
117			os_free(data);
118			return NULL;
119		}
120	} else {
121		if (sm->user == NULL || sm->user->password == NULL) {
122			/*
123			 * In theory, this should not really be needed, but
124			 * Windows 7 uses Registrar mode to probe AP's WPS
125			 * capabilities before trying to use Enrollee and fails
126			 * if the AP does not allow that probing to happen..
127			 */
128			wpa_printf(MSG_DEBUG, "EAP-WSC: No AP PIN (password) "
129				   "configured for Enrollee functionality - "
130				   "allow for probing capabilities (M1)");
131		} else {
132			cfg.pin = sm->user->password;
133			cfg.pin_len = sm->user->password_len;
134		}
135	}
136	cfg.assoc_wps_ie = sm->assoc_wps_ie;
137	cfg.peer_addr = sm->peer_addr;
138	if (0 /* TODO: could provide option for forcing PSK format */)
139		 cfg.use_psk_key = 1;
140	data->wps = wps_init(&cfg);
141	if (data->wps == NULL) {
142		os_free(data);
143		return NULL;
144	}
145	data->fragment_size = WSC_FRAGMENT_SIZE;
146
147	return data;
148}
149
150
151static void eap_wsc_reset(struct eap_sm *sm, void *priv)
152{
153	struct eap_wsc_data *data = priv;
154	eloop_cancel_timeout(eap_wsc_ext_reg_timeout, sm, data);
155	wpabuf_free(data->in_buf);
156	wpabuf_free(data->out_buf);
157	wps_deinit(data->wps);
158	os_free(data);
159}
160
161
162static struct wpabuf * eap_wsc_build_start(struct eap_sm *sm,
163					   struct eap_wsc_data *data, u8 id)
164{
165	struct wpabuf *req;
166
167	req = eap_msg_alloc(EAP_VENDOR_WFA, EAP_VENDOR_TYPE_WSC, 2,
168			    EAP_CODE_REQUEST, id);
169	if (req == NULL) {
170		wpa_printf(MSG_ERROR, "EAP-WSC: Failed to allocate memory for "
171			   "request");
172		return NULL;
173	}
174
175	wpa_printf(MSG_DEBUG, "EAP-WSC: Send WSC/Start");
176	wpabuf_put_u8(req, WSC_Start); /* Op-Code */
177	wpabuf_put_u8(req, 0); /* Flags */
178
179	return req;
180}
181
182
183static struct wpabuf * eap_wsc_build_msg(struct eap_wsc_data *data, u8 id)
184{
185	struct wpabuf *req;
186	u8 flags;
187	size_t send_len, plen;
188
189	flags = 0;
190	send_len = wpabuf_len(data->out_buf) - data->out_used;
191	if (2 + send_len > data->fragment_size) {
192		send_len = data->fragment_size - 2;
193		flags |= WSC_FLAGS_MF;
194		if (data->out_used == 0) {
195			flags |= WSC_FLAGS_LF;
196			send_len -= 2;
197		}
198	}
199	plen = 2 + send_len;
200	if (flags & WSC_FLAGS_LF)
201		plen += 2;
202	req = eap_msg_alloc(EAP_VENDOR_WFA, EAP_VENDOR_TYPE_WSC, plen,
203			    EAP_CODE_REQUEST, id);
204	if (req == NULL) {
205		wpa_printf(MSG_ERROR, "EAP-WSC: Failed to allocate memory for "
206			   "request");
207		return NULL;
208	}
209
210	wpabuf_put_u8(req, data->out_op_code); /* Op-Code */
211	wpabuf_put_u8(req, flags); /* Flags */
212	if (flags & WSC_FLAGS_LF)
213		wpabuf_put_be16(req, wpabuf_len(data->out_buf));
214
215	wpabuf_put_data(req, wpabuf_head_u8(data->out_buf) + data->out_used,
216			send_len);
217	data->out_used += send_len;
218
219	if (data->out_used == wpabuf_len(data->out_buf)) {
220		wpa_printf(MSG_DEBUG, "EAP-WSC: Sending out %lu bytes "
221			   "(message sent completely)",
222			   (unsigned long) send_len);
223		wpabuf_free(data->out_buf);
224		data->out_buf = NULL;
225		data->out_used = 0;
226		eap_wsc_state(data, MESG);
227	} else {
228		wpa_printf(MSG_DEBUG, "EAP-WSC: Sending out %lu bytes "
229			   "(%lu more to send)", (unsigned long) send_len,
230			   (unsigned long) wpabuf_len(data->out_buf) -
231			   data->out_used);
232		eap_wsc_state(data, WAIT_FRAG_ACK);
233	}
234
235	return req;
236}
237
238
239static struct wpabuf * eap_wsc_buildReq(struct eap_sm *sm, void *priv, u8 id)
240{
241	struct eap_wsc_data *data = priv;
242
243	switch (data->state) {
244	case START:
245		return eap_wsc_build_start(sm, data, id);
246	case MESG:
247		if (data->out_buf == NULL) {
248			data->out_buf = wps_get_msg(data->wps,
249						    &data->out_op_code);
250			if (data->out_buf == NULL) {
251				wpa_printf(MSG_DEBUG, "EAP-WSC: Failed to "
252					   "receive message from WPS");
253				return NULL;
254			}
255			data->out_used = 0;
256		}
257		/* pass through */
258	case WAIT_FRAG_ACK:
259		return eap_wsc_build_msg(data, id);
260	case FRAG_ACK:
261		return eap_wsc_build_frag_ack(id, EAP_CODE_REQUEST);
262	default:
263		wpa_printf(MSG_DEBUG, "EAP-WSC: Unexpected state %d in "
264			   "buildReq", data->state);
265		return NULL;
266	}
267}
268
269
270static Boolean eap_wsc_check(struct eap_sm *sm, void *priv,
271			     struct wpabuf *respData)
272{
273	const u8 *pos;
274	size_t len;
275
276	pos = eap_hdr_validate(EAP_VENDOR_WFA, EAP_VENDOR_TYPE_WSC,
277			       respData, &len);
278	if (pos == NULL || len < 2) {
279		wpa_printf(MSG_INFO, "EAP-WSC: Invalid frame");
280		return TRUE;
281	}
282
283	return FALSE;
284}
285
286
287static int eap_wsc_process_cont(struct eap_wsc_data *data,
288				const u8 *buf, size_t len, u8 op_code)
289{
290	/* Process continuation of a pending message */
291	if (op_code != data->in_op_code) {
292		wpa_printf(MSG_DEBUG, "EAP-WSC: Unexpected Op-Code %d in "
293			   "fragment (expected %d)",
294			   op_code, data->in_op_code);
295		eap_wsc_state(data, FAIL);
296		return -1;
297	}
298
299	if (len > wpabuf_tailroom(data->in_buf)) {
300		wpa_printf(MSG_DEBUG, "EAP-WSC: Fragment overflow");
301		eap_wsc_state(data, FAIL);
302		return -1;
303	}
304
305	wpabuf_put_data(data->in_buf, buf, len);
306	wpa_printf(MSG_DEBUG, "EAP-WSC: Received %lu bytes, waiting for %lu "
307		   "bytes more", (unsigned long) len,
308		   (unsigned long) wpabuf_tailroom(data->in_buf));
309
310	return 0;
311}
312
313
314static int eap_wsc_process_fragment(struct eap_wsc_data *data,
315				    u8 flags, u8 op_code, u16 message_length,
316				    const u8 *buf, size_t len)
317{
318	/* Process a fragment that is not the last one of the message */
319	if (data->in_buf == NULL && !(flags & WSC_FLAGS_LF)) {
320		wpa_printf(MSG_DEBUG, "EAP-WSC: No Message Length "
321			   "field in a fragmented packet");
322		return -1;
323	}
324
325	if (data->in_buf == NULL) {
326		/* First fragment of the message */
327		data->in_buf = wpabuf_alloc(message_length);
328		if (data->in_buf == NULL) {
329			wpa_printf(MSG_DEBUG, "EAP-WSC: No memory for "
330				   "message");
331			return -1;
332		}
333		data->in_op_code = op_code;
334		wpabuf_put_data(data->in_buf, buf, len);
335		wpa_printf(MSG_DEBUG, "EAP-WSC: Received %lu bytes in "
336			   "first fragment, waiting for %lu bytes more",
337			   (unsigned long) len,
338			   (unsigned long) wpabuf_tailroom(data->in_buf));
339	}
340
341	return 0;
342}
343
344
345static void eap_wsc_process(struct eap_sm *sm, void *priv,
346			    struct wpabuf *respData)
347{
348	struct eap_wsc_data *data = priv;
349	const u8 *start, *pos, *end;
350	size_t len;
351	u8 op_code, flags;
352	u16 message_length = 0;
353	enum wps_process_res res;
354	struct wpabuf tmpbuf;
355
356	eloop_cancel_timeout(eap_wsc_ext_reg_timeout, sm, data);
357	if (data->ext_reg_timeout) {
358		eap_wsc_state(data, FAIL);
359		return;
360	}
361
362	pos = eap_hdr_validate(EAP_VENDOR_WFA, EAP_VENDOR_TYPE_WSC,
363			       respData, &len);
364	if (pos == NULL || len < 2)
365		return; /* Should not happen; message already verified */
366
367	start = pos;
368	end = start + len;
369
370	op_code = *pos++;
371	flags = *pos++;
372	if (flags & WSC_FLAGS_LF) {
373		if (end - pos < 2) {
374			wpa_printf(MSG_DEBUG, "EAP-WSC: Message underflow");
375			return;
376		}
377		message_length = WPA_GET_BE16(pos);
378		pos += 2;
379
380		if (message_length < end - pos) {
381			wpa_printf(MSG_DEBUG, "EAP-WSC: Invalid Message "
382				   "Length");
383			return;
384		}
385	}
386
387	wpa_printf(MSG_DEBUG, "EAP-WSC: Received packet: Op-Code %d "
388		   "Flags 0x%x Message Length %d",
389		   op_code, flags, message_length);
390
391	if (data->state == WAIT_FRAG_ACK) {
392		if (op_code != WSC_FRAG_ACK) {
393			wpa_printf(MSG_DEBUG, "EAP-WSC: Unexpected Op-Code %d "
394				   "in WAIT_FRAG_ACK state", op_code);
395			eap_wsc_state(data, FAIL);
396			return;
397		}
398		wpa_printf(MSG_DEBUG, "EAP-WSC: Fragment acknowledged");
399		eap_wsc_state(data, MESG);
400		return;
401	}
402
403	if (op_code != WSC_ACK && op_code != WSC_NACK && op_code != WSC_MSG &&
404	    op_code != WSC_Done) {
405		wpa_printf(MSG_DEBUG, "EAP-WSC: Unexpected Op-Code %d",
406			   op_code);
407		eap_wsc_state(data, FAIL);
408		return;
409	}
410
411	if (data->in_buf &&
412	    eap_wsc_process_cont(data, pos, end - pos, op_code) < 0) {
413		eap_wsc_state(data, FAIL);
414		return;
415	}
416
417	if (flags & WSC_FLAGS_MF) {
418		if (eap_wsc_process_fragment(data, flags, op_code,
419					     message_length, pos, end - pos) <
420		    0)
421			eap_wsc_state(data, FAIL);
422		else
423			eap_wsc_state(data, FRAG_ACK);
424		return;
425	}
426
427	if (data->in_buf == NULL) {
428		/* Wrap unfragmented messages as wpabuf without extra copy */
429		wpabuf_set(&tmpbuf, pos, end - pos);
430		data->in_buf = &tmpbuf;
431	}
432
433	res = wps_process_msg(data->wps, op_code, data->in_buf);
434	switch (res) {
435	case WPS_DONE:
436		wpa_printf(MSG_DEBUG, "EAP-WSC: WPS processing completed "
437			   "successfully - report EAP failure");
438		eap_wsc_state(data, FAIL);
439		break;
440	case WPS_CONTINUE:
441		eap_wsc_state(data, MESG);
442		break;
443	case WPS_FAILURE:
444		wpa_printf(MSG_DEBUG, "EAP-WSC: WPS processing failed");
445		eap_wsc_state(data, FAIL);
446		break;
447	case WPS_PENDING:
448		eap_wsc_state(data, MESG);
449		sm->method_pending = METHOD_PENDING_WAIT;
450		eloop_cancel_timeout(eap_wsc_ext_reg_timeout, sm, data);
451		eloop_register_timeout(5, 0, eap_wsc_ext_reg_timeout,
452				       sm, data);
453		break;
454	}
455
456	if (data->in_buf != &tmpbuf)
457		wpabuf_free(data->in_buf);
458	data->in_buf = NULL;
459}
460
461
462static Boolean eap_wsc_isDone(struct eap_sm *sm, void *priv)
463{
464	struct eap_wsc_data *data = priv;
465	return data->state == FAIL;
466}
467
468
469static Boolean eap_wsc_isSuccess(struct eap_sm *sm, void *priv)
470{
471	/* EAP-WSC will always result in EAP-Failure */
472	return FALSE;
473}
474
475
476static int eap_wsc_getTimeout(struct eap_sm *sm, void *priv)
477{
478	/* Recommended retransmit times: retransmit timeout 5 seconds,
479	 * per-message timeout 15 seconds, i.e., 3 tries. */
480	sm->MaxRetrans = 2; /* total 3 attempts */
481	return 5;
482}
483
484
485int eap_server_wsc_register(void)
486{
487	struct eap_method *eap;
488	int ret;
489
490	eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION,
491				      EAP_VENDOR_WFA, EAP_VENDOR_TYPE_WSC,
492				      "WSC");
493	if (eap == NULL)
494		return -1;
495
496	eap->init = eap_wsc_init;
497	eap->reset = eap_wsc_reset;
498	eap->buildReq = eap_wsc_buildReq;
499	eap->check = eap_wsc_check;
500	eap->process = eap_wsc_process;
501	eap->isDone = eap_wsc_isDone;
502	eap->isSuccess = eap_wsc_isSuccess;
503	eap->getTimeout = eap_wsc_getTimeout;
504
505	ret = eap_server_method_register(eap);
506	if (ret)
507		eap_server_method_free(eap);
508	return ret;
509}
510