1 /*
2  * EAP-WSC peer for Wi-Fi Protected Setup
3  * Copyright (c) 2007-2009, 2012, 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 "uuid.h"
13 #include "eap_i.h"
14 #include "eap_common/eap_wsc_common.h"
15 #include "wps/wps.h"
16 #include "wps/wps_defs.h"
17 
18 
19 struct eap_wsc_data {
20 	enum { WAIT_START, MESG, WAIT_FRAG_ACK, 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 	struct wps_context *wps_ctx;
29 };
30 
31 
eap_wsc_state_txt(int state)32 static const char * eap_wsc_state_txt(int state)
33 {
34 	switch (state) {
35 	case WAIT_START:
36 		return "WAIT_START";
37 	case MESG:
38 		return "MESG";
39 	case WAIT_FRAG_ACK:
40 		return "WAIT_FRAG_ACK";
41 	case FAIL:
42 		return "FAIL";
43 	default:
44 		return "?";
45 	}
46 }
47 
48 
eap_wsc_state(struct eap_wsc_data * data,int state)49 static void eap_wsc_state(struct eap_wsc_data *data, int state)
50 {
51 	wpa_printf(MSG_DEBUG, "EAP-WSC: %s -> %s",
52 		   eap_wsc_state_txt(data->state),
53 		   eap_wsc_state_txt(state));
54 	data->state = state;
55 }
56 
57 
eap_wsc_new_ap_settings(struct wps_credential * cred,const char * params)58 static int eap_wsc_new_ap_settings(struct wps_credential *cred,
59 				   const char *params)
60 {
61 	const char *pos, *end;
62 	size_t len;
63 
64 	os_memset(cred, 0, sizeof(*cred));
65 
66 	pos = os_strstr(params, "new_ssid=");
67 	if (pos == NULL)
68 		return 0;
69 	pos += 9;
70 	end = os_strchr(pos, ' ');
71 	if (end == NULL)
72 		len = os_strlen(pos);
73 	else
74 		len = end - pos;
75 	if ((len & 1) || len > 2 * sizeof(cred->ssid) ||
76 	    hexstr2bin(pos, cred->ssid, len / 2)) {
77 		wpa_printf(MSG_DEBUG, "EAP-WSC: Invalid new_ssid");
78 		return -1;
79 	}
80 	cred->ssid_len = len / 2;
81 
82 	pos = os_strstr(params, "new_auth=");
83 	if (pos == NULL) {
84 		wpa_printf(MSG_DEBUG, "EAP-WSC: Missing new_auth");
85 		return -1;
86 	}
87 	if (os_strncmp(pos + 9, "OPEN", 4) == 0)
88 		cred->auth_type = WPS_AUTH_OPEN;
89 	else if (os_strncmp(pos + 9, "WPAPSK", 6) == 0)
90 		cred->auth_type = WPS_AUTH_WPAPSK;
91 	else if (os_strncmp(pos + 9, "WPA2PSK", 7) == 0)
92 		cred->auth_type = WPS_AUTH_WPA2PSK;
93 	else {
94 		wpa_printf(MSG_DEBUG, "EAP-WSC: Unknown new_auth");
95 		return -1;
96 	}
97 
98 	pos = os_strstr(params, "new_encr=");
99 	if (pos == NULL) {
100 		wpa_printf(MSG_DEBUG, "EAP-WSC: Missing new_encr");
101 		return -1;
102 	}
103 	if (os_strncmp(pos + 9, "NONE", 4) == 0)
104 		cred->encr_type = WPS_ENCR_NONE;
105 #ifdef CONFIG_TESTING_OPTIONS
106 	else if (os_strncmp(pos + 9, "WEP", 3) == 0)
107 		cred->encr_type = WPS_ENCR_WEP;
108 #endif /* CONFIG_TESTING_OPTIONS */
109 	else if (os_strncmp(pos + 9, "TKIP", 4) == 0)
110 		cred->encr_type = WPS_ENCR_TKIP;
111 	else if (os_strncmp(pos + 9, "CCMP", 4) == 0)
112 		cred->encr_type = WPS_ENCR_AES;
113 	else {
114 		wpa_printf(MSG_DEBUG, "EAP-WSC: Unknown new_encr");
115 		return -1;
116 	}
117 
118 	pos = os_strstr(params, "new_key=");
119 	if (pos == NULL)
120 		return 0;
121 	pos += 8;
122 	end = os_strchr(pos, ' ');
123 	if (end == NULL)
124 		len = os_strlen(pos);
125 	else
126 		len = end - pos;
127 	if ((len & 1) || len > 2 * sizeof(cred->key) ||
128 	    hexstr2bin(pos, cred->key, len / 2)) {
129 		wpa_printf(MSG_DEBUG, "EAP-WSC: Invalid new_key");
130 		return -1;
131 	}
132 	cred->key_len = len / 2;
133 
134 	return 1;
135 }
136 
137 
eap_wsc_init(struct eap_sm * sm)138 static void * eap_wsc_init(struct eap_sm *sm)
139 {
140 	struct eap_wsc_data *data;
141 	const u8 *identity;
142 	size_t identity_len;
143 	int registrar;
144 	struct wps_config cfg;
145 	const char *pos, *end;
146 	const char *phase1;
147 	struct wps_context *wps;
148 	struct wps_credential new_ap_settings;
149 	int res;
150 	int nfc = 0;
151 	u8 pkhash[WPS_OOB_PUBKEY_HASH_LEN];
152 
153 	wps = sm->wps;
154 	if (wps == NULL) {
155 		wpa_printf(MSG_ERROR, "EAP-WSC: WPS context not available");
156 		return NULL;
157 	}
158 
159 	identity = eap_get_config_identity(sm, &identity_len);
160 
161 	if (identity && identity_len == WSC_ID_REGISTRAR_LEN &&
162 	    os_memcmp(identity, WSC_ID_REGISTRAR, WSC_ID_REGISTRAR_LEN) == 0)
163 		registrar = 1; /* Supplicant is Registrar */
164 	else if (identity && identity_len == WSC_ID_ENROLLEE_LEN &&
165 	    os_memcmp(identity, WSC_ID_ENROLLEE, WSC_ID_ENROLLEE_LEN) == 0)
166 		registrar = 0; /* Supplicant is Enrollee */
167 	else {
168 		wpa_hexdump_ascii(MSG_INFO, "EAP-WSC: Unexpected identity",
169 				  identity, identity_len);
170 		return NULL;
171 	}
172 
173 	data = os_zalloc(sizeof(*data));
174 	if (data == NULL)
175 		return NULL;
176 	data->state = registrar ? MESG : WAIT_START;
177 	data->registrar = registrar;
178 	data->wps_ctx = wps;
179 
180 	os_memset(&cfg, 0, sizeof(cfg));
181 	cfg.wps = wps;
182 	cfg.registrar = registrar;
183 
184 	phase1 = eap_get_config_phase1(sm);
185 	if (phase1 == NULL) {
186 		wpa_printf(MSG_INFO, "EAP-WSC: phase1 configuration data not "
187 			   "set");
188 		os_free(data);
189 		return NULL;
190 	}
191 
192 	pos = os_strstr(phase1, "pin=");
193 	if (pos) {
194 		pos += 4;
195 		cfg.pin = (const u8 *) pos;
196 		while (*pos != '\0' && *pos != ' ')
197 			pos++;
198 		cfg.pin_len = pos - (const char *) cfg.pin;
199 		if (cfg.pin_len == 6 &&
200 		    os_strncmp((const char *) cfg.pin, "nfc-pw", 6) == 0) {
201 			cfg.pin = NULL;
202 			cfg.pin_len = 0;
203 			nfc = 1;
204 		}
205 	} else {
206 		pos = os_strstr(phase1, "pbc=1");
207 		if (pos)
208 			cfg.pbc = 1;
209 	}
210 
211 	pos = os_strstr(phase1, "dev_pw_id=");
212 	if (pos) {
213 		u16 id = atoi(pos + 10);
214 		if (id == DEV_PW_NFC_CONNECTION_HANDOVER)
215 			nfc = 1;
216 		if (cfg.pin || id == DEV_PW_NFC_CONNECTION_HANDOVER)
217 			cfg.dev_pw_id = id;
218 	}
219 
220 	if (cfg.pin == NULL && !cfg.pbc && !nfc) {
221 		wpa_printf(MSG_INFO, "EAP-WSC: PIN or PBC not set in phase1 "
222 			   "configuration data");
223 		os_free(data);
224 		return NULL;
225 	}
226 
227 	pos = os_strstr(phase1, " pkhash=");
228 	if (pos) {
229 		size_t len;
230 		pos += 8;
231 		end = os_strchr(pos, ' ');
232 		if (end)
233 			len = end - pos;
234 		else
235 			len = os_strlen(pos);
236 		if (len != 2 * WPS_OOB_PUBKEY_HASH_LEN ||
237 		    hexstr2bin(pos, pkhash, WPS_OOB_PUBKEY_HASH_LEN)) {
238 			wpa_printf(MSG_INFO, "EAP-WSC: Invalid pkhash");
239 			os_free(data);
240 			return NULL;
241 		}
242 		cfg.peer_pubkey_hash = pkhash;
243 	}
244 
245 	res = eap_wsc_new_ap_settings(&new_ap_settings, phase1);
246 	if (res < 0) {
247 		os_free(data);
248 		wpa_printf(MSG_DEBUG, "EAP-WSC: Failed to parse new AP "
249 			   "settings");
250 		return NULL;
251 	}
252 	if (res == 1) {
253 		wpa_printf(MSG_DEBUG, "EAP-WSC: Provide new AP settings for "
254 			   "WPS");
255 		cfg.new_ap_settings = &new_ap_settings;
256 	}
257 
258 	if (os_strstr(phase1, "multi_ap=1"))
259 		cfg.multi_ap_backhaul_sta = 1;
260 
261 	data->wps = wps_init(&cfg);
262 	if (data->wps == NULL) {
263 		os_free(data);
264 		wpa_printf(MSG_DEBUG, "EAP-WSC: wps_init failed");
265 		return NULL;
266 	}
267 	res = eap_get_config_fragment_size(sm);
268 	if (res > 0)
269 		data->fragment_size = res;
270 	else
271 		data->fragment_size = WSC_FRAGMENT_SIZE;
272 	wpa_printf(MSG_DEBUG, "EAP-WSC: Fragment size limit %u",
273 		   (unsigned int) data->fragment_size);
274 
275 	if (registrar && cfg.pin) {
276 		wps_registrar_add_pin(data->wps_ctx->registrar, NULL, NULL,
277 				      cfg.pin, cfg.pin_len, 0);
278 	}
279 
280 	/* Use reduced client timeout for WPS to avoid long wait */
281 	if (sm->ClientTimeout > 30)
282 		sm->ClientTimeout = 30;
283 
284 	return data;
285 }
286 
287 
eap_wsc_deinit(struct eap_sm * sm,void * priv)288 static void eap_wsc_deinit(struct eap_sm *sm, void *priv)
289 {
290 	struct eap_wsc_data *data = priv;
291 	wpabuf_free(data->in_buf);
292 	wpabuf_free(data->out_buf);
293 	wps_deinit(data->wps);
294 	os_free(data->wps_ctx->network_key);
295 	data->wps_ctx->network_key = NULL;
296 	os_free(data);
297 }
298 
299 
eap_wsc_build_msg(struct eap_wsc_data * data,struct eap_method_ret * ret,u8 id)300 static struct wpabuf * eap_wsc_build_msg(struct eap_wsc_data *data,
301 					 struct eap_method_ret *ret, u8 id)
302 {
303 	struct wpabuf *resp;
304 	u8 flags;
305 	size_t send_len, plen;
306 
307 	ret->ignore = FALSE;
308 	wpa_printf(MSG_DEBUG, "EAP-WSC: Generating Response");
309 	ret->allowNotifications = TRUE;
310 
311 	flags = 0;
312 	send_len = wpabuf_len(data->out_buf) - data->out_used;
313 	if (2 + send_len > data->fragment_size) {
314 		send_len = data->fragment_size - 2;
315 		flags |= WSC_FLAGS_MF;
316 		if (data->out_used == 0) {
317 			flags |= WSC_FLAGS_LF;
318 			send_len -= 2;
319 		}
320 	}
321 	plen = 2 + send_len;
322 	if (flags & WSC_FLAGS_LF)
323 		plen += 2;
324 	resp = eap_msg_alloc(EAP_VENDOR_WFA, EAP_VENDOR_TYPE_WSC, plen,
325 			     EAP_CODE_RESPONSE, id);
326 	if (resp == NULL)
327 		return NULL;
328 
329 	wpabuf_put_u8(resp, data->out_op_code); /* Op-Code */
330 	wpabuf_put_u8(resp, flags); /* Flags */
331 	if (flags & WSC_FLAGS_LF)
332 		wpabuf_put_be16(resp, wpabuf_len(data->out_buf));
333 
334 	wpabuf_put_data(resp, wpabuf_head_u8(data->out_buf) + data->out_used,
335 			send_len);
336 	data->out_used += send_len;
337 
338 	ret->methodState = METHOD_MAY_CONT;
339 	ret->decision = DECISION_FAIL;
340 
341 	if (data->out_used == wpabuf_len(data->out_buf)) {
342 		wpa_printf(MSG_DEBUG, "EAP-WSC: Sending out %lu bytes "
343 			   "(message sent completely)",
344 			   (unsigned long) send_len);
345 		wpabuf_free(data->out_buf);
346 		data->out_buf = NULL;
347 		data->out_used = 0;
348 		if ((data->state == FAIL && data->out_op_code == WSC_ACK) ||
349 		    data->out_op_code == WSC_NACK ||
350 		    data->out_op_code == WSC_Done) {
351 			eap_wsc_state(data, FAIL);
352 			ret->methodState = METHOD_DONE;
353 		} else
354 			eap_wsc_state(data, MESG);
355 	} else {
356 		wpa_printf(MSG_DEBUG, "EAP-WSC: Sending out %lu bytes "
357 			   "(%lu more to send)", (unsigned long) send_len,
358 			   (unsigned long) wpabuf_len(data->out_buf) -
359 			   data->out_used);
360 		eap_wsc_state(data, WAIT_FRAG_ACK);
361 	}
362 
363 	return resp;
364 }
365 
366 
eap_wsc_process_cont(struct eap_wsc_data * data,const u8 * buf,size_t len,u8 op_code)367 static int eap_wsc_process_cont(struct eap_wsc_data *data,
368 				const u8 *buf, size_t len, u8 op_code)
369 {
370 	/* Process continuation of a pending message */
371 	if (op_code != data->in_op_code) {
372 		wpa_printf(MSG_DEBUG, "EAP-WSC: Unexpected Op-Code %d in "
373 			   "fragment (expected %d)",
374 			   op_code, data->in_op_code);
375 		return -1;
376 	}
377 
378 	if (len > wpabuf_tailroom(data->in_buf)) {
379 		wpa_printf(MSG_DEBUG, "EAP-WSC: Fragment overflow");
380 		eap_wsc_state(data, FAIL);
381 		return -1;
382 	}
383 
384 	wpabuf_put_data(data->in_buf, buf, len);
385 	wpa_printf(MSG_DEBUG, "EAP-WSC: Received %lu bytes, waiting "
386 		   "for %lu bytes more", (unsigned long) len,
387 		   (unsigned long) wpabuf_tailroom(data->in_buf));
388 
389 	return 0;
390 }
391 
392 
eap_wsc_process_fragment(struct eap_wsc_data * data,struct eap_method_ret * ret,u8 id,u8 flags,u8 op_code,u16 message_length,const u8 * buf,size_t len)393 static struct wpabuf * eap_wsc_process_fragment(struct eap_wsc_data *data,
394 						struct eap_method_ret *ret,
395 						u8 id, u8 flags, u8 op_code,
396 						u16 message_length,
397 						const u8 *buf, size_t len)
398 {
399 	/* Process a fragment that is not the last one of the message */
400 	if (data->in_buf == NULL && !(flags & WSC_FLAGS_LF)) {
401 		wpa_printf(MSG_DEBUG, "EAP-WSC: No Message Length field in a "
402 			   "fragmented packet");
403 		ret->ignore = TRUE;
404 		return NULL;
405 	}
406 
407 	if (data->in_buf == NULL) {
408 		/* First fragment of the message */
409 		data->in_buf = wpabuf_alloc(message_length);
410 		if (data->in_buf == NULL) {
411 			wpa_printf(MSG_DEBUG, "EAP-WSC: No memory for "
412 				   "message");
413 			ret->ignore = TRUE;
414 			return NULL;
415 		}
416 		data->in_op_code = op_code;
417 		wpabuf_put_data(data->in_buf, buf, len);
418 		wpa_printf(MSG_DEBUG, "EAP-WSC: Received %lu bytes in first "
419 			   "fragment, waiting for %lu bytes more",
420 			   (unsigned long) len,
421 			   (unsigned long) wpabuf_tailroom(data->in_buf));
422 	}
423 
424 	return eap_wsc_build_frag_ack(id, EAP_CODE_RESPONSE);
425 }
426 
427 
eap_wsc_process(struct eap_sm * sm,void * priv,struct eap_method_ret * ret,const struct wpabuf * reqData)428 static struct wpabuf * eap_wsc_process(struct eap_sm *sm, void *priv,
429 				       struct eap_method_ret *ret,
430 				       const struct wpabuf *reqData)
431 {
432 	struct eap_wsc_data *data = priv;
433 	const u8 *start, *pos, *end;
434 	size_t len;
435 	u8 op_code, flags, id;
436 	u16 message_length = 0;
437 	enum wps_process_res res;
438 	struct wpabuf tmpbuf;
439 	struct wpabuf *r;
440 
441 	pos = eap_hdr_validate(EAP_VENDOR_WFA, EAP_VENDOR_TYPE_WSC, reqData,
442 			       &len);
443 	if (pos == NULL || len < 2) {
444 		ret->ignore = TRUE;
445 		return NULL;
446 	}
447 
448 	id = eap_get_id(reqData);
449 
450 	start = pos;
451 	end = start + len;
452 
453 	op_code = *pos++;
454 	flags = *pos++;
455 	if (flags & WSC_FLAGS_LF) {
456 		if (end - pos < 2) {
457 			wpa_printf(MSG_DEBUG, "EAP-WSC: Message underflow");
458 			ret->ignore = TRUE;
459 			return NULL;
460 		}
461 		message_length = WPA_GET_BE16(pos);
462 		pos += 2;
463 
464 		if (message_length < end - pos || message_length > 50000) {
465 			wpa_printf(MSG_DEBUG, "EAP-WSC: Invalid Message "
466 				   "Length");
467 			ret->ignore = TRUE;
468 			return NULL;
469 		}
470 	}
471 
472 	wpa_printf(MSG_DEBUG, "EAP-WSC: Received packet: Op-Code %d "
473 		   "Flags 0x%x Message Length %d",
474 		   op_code, flags, message_length);
475 
476 	if (data->state == WAIT_FRAG_ACK) {
477 		if (op_code != WSC_FRAG_ACK) {
478 			wpa_printf(MSG_DEBUG, "EAP-WSC: Unexpected Op-Code %d "
479 				   "in WAIT_FRAG_ACK state", op_code);
480 			ret->ignore = TRUE;
481 			return NULL;
482 		}
483 		wpa_printf(MSG_DEBUG, "EAP-WSC: Fragment acknowledged");
484 		eap_wsc_state(data, MESG);
485 		return eap_wsc_build_msg(data, ret, id);
486 	}
487 
488 	if (op_code != WSC_ACK && op_code != WSC_NACK && op_code != WSC_MSG &&
489 	    op_code != WSC_Done && op_code != WSC_Start) {
490 		wpa_printf(MSG_DEBUG, "EAP-WSC: Unexpected Op-Code %d",
491 			   op_code);
492 		ret->ignore = TRUE;
493 		return NULL;
494 	}
495 
496 	if (data->state == WAIT_START) {
497 		if (op_code != WSC_Start) {
498 			wpa_printf(MSG_DEBUG, "EAP-WSC: Unexpected Op-Code %d "
499 				   "in WAIT_START state", op_code);
500 			ret->ignore = TRUE;
501 			return NULL;
502 		}
503 		wpa_printf(MSG_DEBUG, "EAP-WSC: Received start");
504 		eap_wsc_state(data, MESG);
505 		/* Start message has empty payload, skip processing */
506 		goto send_msg;
507 	} else if (op_code == WSC_Start) {
508 		wpa_printf(MSG_DEBUG, "EAP-WSC: Unexpected Op-Code %d",
509 			   op_code);
510 		ret->ignore = TRUE;
511 		return NULL;
512 	}
513 
514 	if (data->in_buf &&
515 	    eap_wsc_process_cont(data, pos, end - pos, op_code) < 0) {
516 		ret->ignore = TRUE;
517 		return NULL;
518 	}
519 
520 	if (flags & WSC_FLAGS_MF) {
521 		return eap_wsc_process_fragment(data, ret, id, flags, op_code,
522 						message_length, pos,
523 						end - pos);
524 	}
525 
526 	if (data->in_buf == NULL) {
527 		/* Wrap unfragmented messages as wpabuf without extra copy */
528 		wpabuf_set(&tmpbuf, pos, end - pos);
529 		data->in_buf = &tmpbuf;
530 	}
531 
532 	res = wps_process_msg(data->wps, op_code, data->in_buf);
533 	switch (res) {
534 	case WPS_DONE:
535 		wpa_printf(MSG_DEBUG, "EAP-WSC: WPS processing completed "
536 			   "successfully - wait for EAP failure");
537 		eap_wsc_state(data, FAIL);
538 		break;
539 	case WPS_CONTINUE:
540 		eap_wsc_state(data, MESG);
541 		break;
542 	case WPS_FAILURE:
543 	case WPS_PENDING:
544 		wpa_printf(MSG_DEBUG, "EAP-WSC: WPS processing failed");
545 		eap_wsc_state(data, FAIL);
546 		break;
547 	}
548 
549 	if (data->in_buf != &tmpbuf)
550 		wpabuf_free(data->in_buf);
551 	data->in_buf = NULL;
552 
553 send_msg:
554 	if (data->out_buf == NULL) {
555 		data->out_buf = wps_get_msg(data->wps, &data->out_op_code);
556 		if (data->out_buf == NULL) {
557 			wpa_printf(MSG_DEBUG, "EAP-WSC: Failed to receive "
558 				   "message from WPS");
559 			eap_wsc_state(data, FAIL);
560 			ret->methodState = METHOD_DONE;
561 			ret->decision = DECISION_FAIL;
562 			return NULL;
563 		}
564 		data->out_used = 0;
565 	}
566 
567 	eap_wsc_state(data, MESG);
568 	r = eap_wsc_build_msg(data, ret, id);
569 	if (data->state == FAIL && ret->methodState == METHOD_DONE) {
570 		/* Use reduced client timeout for WPS to avoid long wait */
571 		if (sm->ClientTimeout > 2)
572 			sm->ClientTimeout = 2;
573 	}
574 	return r;
575 }
576 
577 
eap_peer_wsc_register(void)578 int eap_peer_wsc_register(void)
579 {
580 	struct eap_method *eap;
581 
582 	eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
583 				    EAP_VENDOR_WFA, EAP_VENDOR_TYPE_WSC,
584 				    "WSC");
585 	if (eap == NULL)
586 		return -1;
587 
588 	eap->init = eap_wsc_init;
589 	eap->deinit = eap_wsc_deinit;
590 	eap->process = eap_wsc_process;
591 
592 	return eap_peer_method_register(eap);
593 }
594