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      1 /*
      2  * EAP-WSC peer for Wi-Fi Protected Setup
      3  * Copyright (c) 2007-2009, 2012, Jouni Malinen <j (at) 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, 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 	struct wps_context *wps_ctx;
     29 };
     30 
     31 
     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 FRAG_ACK:
     40 		return "FRAG_ACK";
     41 	case WAIT_FRAG_ACK:
     42 		return "WAIT_FRAG_ACK";
     43 	case DONE:
     44 		return "DONE";
     45 	case FAIL:
     46 		return "FAIL";
     47 	default:
     48 		return "?";
     49 	}
     50 }
     51 
     52 
     53 static void eap_wsc_state(struct eap_wsc_data *data, int state)
     54 {
     55 	wpa_printf(MSG_DEBUG, "EAP-WSC: %s -> %s",
     56 		   eap_wsc_state_txt(data->state),
     57 		   eap_wsc_state_txt(state));
     58 	data->state = state;
     59 }
     60 
     61 
     62 static int eap_wsc_new_ap_settings(struct wps_credential *cred,
     63 				   const char *params)
     64 {
     65 	const char *pos, *end;
     66 	size_t len;
     67 
     68 	os_memset(cred, 0, sizeof(*cred));
     69 
     70 	pos = os_strstr(params, "new_ssid=");
     71 	if (pos == NULL)
     72 		return 0;
     73 	pos += 9;
     74 	end = os_strchr(pos, ' ');
     75 	if (end == NULL)
     76 		len = os_strlen(pos);
     77 	else
     78 		len = end - pos;
     79 	if ((len & 1) || len > 2 * sizeof(cred->ssid) ||
     80 	    hexstr2bin(pos, cred->ssid, len / 2)) {
     81 		wpa_printf(MSG_DEBUG, "EAP-WSC: Invalid new_ssid");
     82 		return -1;
     83 	}
     84 	cred->ssid_len = len / 2;
     85 
     86 	pos = os_strstr(params, "new_auth=");
     87 	if (pos == NULL) {
     88 		wpa_printf(MSG_DEBUG, "EAP-WSC: Missing new_auth");
     89 		return -1;
     90 	}
     91 	if (os_strncmp(pos + 9, "OPEN", 4) == 0)
     92 		cred->auth_type = WPS_AUTH_OPEN;
     93 	else if (os_strncmp(pos + 9, "WPAPSK", 6) == 0)
     94 		cred->auth_type = WPS_AUTH_WPAPSK;
     95 	else if (os_strncmp(pos + 9, "WPA2PSK", 7) == 0)
     96 		cred->auth_type = WPS_AUTH_WPA2PSK;
     97 	else {
     98 		wpa_printf(MSG_DEBUG, "EAP-WSC: Unknown new_auth");
     99 		return -1;
    100 	}
    101 
    102 	pos = os_strstr(params, "new_encr=");
    103 	if (pos == NULL) {
    104 		wpa_printf(MSG_DEBUG, "EAP-WSC: Missing new_encr");
    105 		return -1;
    106 	}
    107 	if (os_strncmp(pos + 9, "NONE", 4) == 0)
    108 		cred->encr_type = WPS_ENCR_NONE;
    109 #ifdef CONFIG_TESTING_OPTIONS
    110 	else if (os_strncmp(pos + 9, "WEP", 3) == 0)
    111 		cred->encr_type = WPS_ENCR_WEP;
    112 #endif /* CONFIG_TESTING_OPTIONS */
    113 	else if (os_strncmp(pos + 9, "TKIP", 4) == 0)
    114 		cred->encr_type = WPS_ENCR_TKIP;
    115 	else if (os_strncmp(pos + 9, "CCMP", 4) == 0)
    116 		cred->encr_type = WPS_ENCR_AES;
    117 	else {
    118 		wpa_printf(MSG_DEBUG, "EAP-WSC: Unknown new_encr");
    119 		return -1;
    120 	}
    121 
    122 	pos = os_strstr(params, "new_key=");
    123 	if (pos == NULL)
    124 		return 0;
    125 	pos += 8;
    126 	end = os_strchr(pos, ' ');
    127 	if (end == NULL)
    128 		len = os_strlen(pos);
    129 	else
    130 		len = end - pos;
    131 	if ((len & 1) || len > 2 * sizeof(cred->key) ||
    132 	    hexstr2bin(pos, cred->key, len / 2)) {
    133 		wpa_printf(MSG_DEBUG, "EAP-WSC: Invalid new_key");
    134 		return -1;
    135 	}
    136 	cred->key_len = len / 2;
    137 
    138 	return 1;
    139 }
    140 
    141 
    142 static void * eap_wsc_init(struct eap_sm *sm)
    143 {
    144 	struct eap_wsc_data *data;
    145 	const u8 *identity;
    146 	size_t identity_len;
    147 	int registrar;
    148 	struct wps_config cfg;
    149 	const char *pos, *end;
    150 	const char *phase1;
    151 	struct wps_context *wps;
    152 	struct wps_credential new_ap_settings;
    153 	int res;
    154 	int nfc = 0;
    155 	u8 pkhash[WPS_OOB_PUBKEY_HASH_LEN];
    156 
    157 	wps = sm->wps;
    158 	if (wps == NULL) {
    159 		wpa_printf(MSG_ERROR, "EAP-WSC: WPS context not available");
    160 		return NULL;
    161 	}
    162 
    163 	identity = eap_get_config_identity(sm, &identity_len);
    164 
    165 	if (identity && identity_len == WSC_ID_REGISTRAR_LEN &&
    166 	    os_memcmp(identity, WSC_ID_REGISTRAR, WSC_ID_REGISTRAR_LEN) == 0)
    167 		registrar = 1; /* Supplicant is Registrar */
    168 	else if (identity && identity_len == WSC_ID_ENROLLEE_LEN &&
    169 	    os_memcmp(identity, WSC_ID_ENROLLEE, WSC_ID_ENROLLEE_LEN) == 0)
    170 		registrar = 0; /* Supplicant is Enrollee */
    171 	else {
    172 		wpa_hexdump_ascii(MSG_INFO, "EAP-WSC: Unexpected identity",
    173 				  identity, identity_len);
    174 		return NULL;
    175 	}
    176 
    177 	data = os_zalloc(sizeof(*data));
    178 	if (data == NULL)
    179 		return NULL;
    180 	data->state = registrar ? MESG : WAIT_START;
    181 	data->registrar = registrar;
    182 	data->wps_ctx = wps;
    183 
    184 	os_memset(&cfg, 0, sizeof(cfg));
    185 	cfg.wps = wps;
    186 	cfg.registrar = registrar;
    187 
    188 	phase1 = eap_get_config_phase1(sm);
    189 	if (phase1 == NULL) {
    190 		wpa_printf(MSG_INFO, "EAP-WSC: phase1 configuration data not "
    191 			   "set");
    192 		os_free(data);
    193 		return NULL;
    194 	}
    195 
    196 	pos = os_strstr(phase1, "pin=");
    197 	if (pos) {
    198 		pos += 4;
    199 		cfg.pin = (const u8 *) pos;
    200 		while (*pos != '\0' && *pos != ' ')
    201 			pos++;
    202 		cfg.pin_len = pos - (const char *) cfg.pin;
    203 		if (cfg.pin_len == 6 &&
    204 		    os_strncmp((const char *) cfg.pin, "nfc-pw", 6) == 0) {
    205 			cfg.pin = NULL;
    206 			cfg.pin_len = 0;
    207 			nfc = 1;
    208 		}
    209 	} else {
    210 		pos = os_strstr(phase1, "pbc=1");
    211 		if (pos)
    212 			cfg.pbc = 1;
    213 	}
    214 
    215 	pos = os_strstr(phase1, "dev_pw_id=");
    216 	if (pos) {
    217 		u16 id = atoi(pos + 10);
    218 		if (id == DEV_PW_NFC_CONNECTION_HANDOVER)
    219 			nfc = 1;
    220 		if (cfg.pin || id == DEV_PW_NFC_CONNECTION_HANDOVER)
    221 			cfg.dev_pw_id = id;
    222 	}
    223 
    224 	if (cfg.pin == NULL && !cfg.pbc && !nfc) {
    225 		wpa_printf(MSG_INFO, "EAP-WSC: PIN or PBC not set in phase1 "
    226 			   "configuration data");
    227 		os_free(data);
    228 		return NULL;
    229 	}
    230 
    231 	pos = os_strstr(phase1, " pkhash=");
    232 	if (pos) {
    233 		size_t len;
    234 		pos += 8;
    235 		end = os_strchr(pos, ' ');
    236 		if (end)
    237 			len = end - pos;
    238 		else
    239 			len = os_strlen(pos);
    240 		if (len != 2 * WPS_OOB_PUBKEY_HASH_LEN ||
    241 		    hexstr2bin(pos, pkhash, WPS_OOB_PUBKEY_HASH_LEN)) {
    242 			wpa_printf(MSG_INFO, "EAP-WSC: Invalid pkhash");
    243 			os_free(data);
    244 			return NULL;
    245 		}
    246 		cfg.peer_pubkey_hash = pkhash;
    247 	}
    248 
    249 	res = eap_wsc_new_ap_settings(&new_ap_settings, phase1);
    250 	if (res < 0) {
    251 		os_free(data);
    252 		wpa_printf(MSG_DEBUG, "EAP-WSC: Failed to parse new AP "
    253 			   "settings");
    254 		return NULL;
    255 	}
    256 	if (res == 1) {
    257 		wpa_printf(MSG_DEBUG, "EAP-WSC: Provide new AP settings for "
    258 			   "WPS");
    259 		cfg.new_ap_settings = &new_ap_settings;
    260 	}
    261 
    262 	data->wps = wps_init(&cfg);
    263 	if (data->wps == NULL) {
    264 		os_free(data);
    265 		wpa_printf(MSG_DEBUG, "EAP-WSC: wps_init failed");
    266 		return NULL;
    267 	}
    268 	res = eap_get_config_fragment_size(sm);
    269 	if (res > 0)
    270 		data->fragment_size = res;
    271 	else
    272 		data->fragment_size = WSC_FRAGMENT_SIZE;
    273 	wpa_printf(MSG_DEBUG, "EAP-WSC: Fragment size limit %u",
    274 		   (unsigned int) data->fragment_size);
    275 
    276 	if (registrar && cfg.pin) {
    277 		wps_registrar_add_pin(data->wps_ctx->registrar, NULL, NULL,
    278 				      cfg.pin, cfg.pin_len, 0);
    279 	}
    280 
    281 	/* Use reduced client timeout for WPS to avoid long wait */
    282 	if (sm->ClientTimeout > 30)
    283 		sm->ClientTimeout = 30;
    284 
    285 	return data;
    286 }
    287 
    288 
    289 static void eap_wsc_deinit(struct eap_sm *sm, void *priv)
    290 {
    291 	struct eap_wsc_data *data = priv;
    292 	wpabuf_free(data->in_buf);
    293 	wpabuf_free(data->out_buf);
    294 	wps_deinit(data->wps);
    295 	os_free(data->wps_ctx->network_key);
    296 	data->wps_ctx->network_key = NULL;
    297 	os_free(data);
    298 }
    299 
    300 
    301 static struct wpabuf * eap_wsc_build_msg(struct eap_wsc_data *data,
    302 					 struct eap_method_ret *ret, u8 id)
    303 {
    304 	struct wpabuf *resp;
    305 	u8 flags;
    306 	size_t send_len, plen;
    307 
    308 	ret->ignore = FALSE;
    309 	wpa_printf(MSG_DEBUG, "EAP-WSC: Generating Response");
    310 	ret->allowNotifications = TRUE;
    311 
    312 	flags = 0;
    313 	send_len = wpabuf_len(data->out_buf) - data->out_used;
    314 	if (2 + send_len > data->fragment_size) {
    315 		send_len = data->fragment_size - 2;
    316 		flags |= WSC_FLAGS_MF;
    317 		if (data->out_used == 0) {
    318 			flags |= WSC_FLAGS_LF;
    319 			send_len -= 2;
    320 		}
    321 	}
    322 	plen = 2 + send_len;
    323 	if (flags & WSC_FLAGS_LF)
    324 		plen += 2;
    325 	resp = eap_msg_alloc(EAP_VENDOR_WFA, EAP_VENDOR_TYPE_WSC, plen,
    326 			     EAP_CODE_RESPONSE, id);
    327 	if (resp == NULL)
    328 		return NULL;
    329 
    330 	wpabuf_put_u8(resp, data->out_op_code); /* Op-Code */
    331 	wpabuf_put_u8(resp, flags); /* Flags */
    332 	if (flags & WSC_FLAGS_LF)
    333 		wpabuf_put_be16(resp, wpabuf_len(data->out_buf));
    334 
    335 	wpabuf_put_data(resp, wpabuf_head_u8(data->out_buf) + data->out_used,
    336 			send_len);
    337 	data->out_used += send_len;
    338 
    339 	ret->methodState = METHOD_MAY_CONT;
    340 	ret->decision = DECISION_FAIL;
    341 
    342 	if (data->out_used == wpabuf_len(data->out_buf)) {
    343 		wpa_printf(MSG_DEBUG, "EAP-WSC: Sending out %lu bytes "
    344 			   "(message sent completely)",
    345 			   (unsigned long) send_len);
    346 		wpabuf_free(data->out_buf);
    347 		data->out_buf = NULL;
    348 		data->out_used = 0;
    349 		if ((data->state == FAIL && data->out_op_code == WSC_ACK) ||
    350 		    data->out_op_code == WSC_NACK ||
    351 		    data->out_op_code == WSC_Done) {
    352 			eap_wsc_state(data, FAIL);
    353 			ret->methodState = METHOD_DONE;
    354 		} else
    355 			eap_wsc_state(data, MESG);
    356 	} else {
    357 		wpa_printf(MSG_DEBUG, "EAP-WSC: Sending out %lu bytes "
    358 			   "(%lu more to send)", (unsigned long) send_len,
    359 			   (unsigned long) wpabuf_len(data->out_buf) -
    360 			   data->out_used);
    361 		eap_wsc_state(data, WAIT_FRAG_ACK);
    362 	}
    363 
    364 	return resp;
    365 }
    366 
    367 
    368 static int eap_wsc_process_cont(struct eap_wsc_data *data,
    369 				const u8 *buf, size_t len, u8 op_code)
    370 {
    371 	/* Process continuation of a pending message */
    372 	if (op_code != data->in_op_code) {
    373 		wpa_printf(MSG_DEBUG, "EAP-WSC: Unexpected Op-Code %d in "
    374 			   "fragment (expected %d)",
    375 			   op_code, data->in_op_code);
    376 		return -1;
    377 	}
    378 
    379 	if (len > wpabuf_tailroom(data->in_buf)) {
    380 		wpa_printf(MSG_DEBUG, "EAP-WSC: Fragment overflow");
    381 		eap_wsc_state(data, FAIL);
    382 		return -1;
    383 	}
    384 
    385 	wpabuf_put_data(data->in_buf, buf, len);
    386 	wpa_printf(MSG_DEBUG, "EAP-WSC: Received %lu bytes, waiting "
    387 		   "for %lu bytes more", (unsigned long) len,
    388 		   (unsigned long) wpabuf_tailroom(data->in_buf));
    389 
    390 	return 0;
    391 }
    392 
    393 
    394 static struct wpabuf * eap_wsc_process_fragment(struct eap_wsc_data *data,
    395 						struct eap_method_ret *ret,
    396 						u8 id, u8 flags, u8 op_code,
    397 						u16 message_length,
    398 						const u8 *buf, size_t len)
    399 {
    400 	/* Process a fragment that is not the last one of the message */
    401 	if (data->in_buf == NULL && !(flags & WSC_FLAGS_LF)) {
    402 		wpa_printf(MSG_DEBUG, "EAP-WSC: No Message Length field in a "
    403 			   "fragmented packet");
    404 		ret->ignore = TRUE;
    405 		return NULL;
    406 	}
    407 
    408 	if (data->in_buf == NULL) {
    409 		/* First fragment of the message */
    410 		data->in_buf = wpabuf_alloc(message_length);
    411 		if (data->in_buf == NULL) {
    412 			wpa_printf(MSG_DEBUG, "EAP-WSC: No memory for "
    413 				   "message");
    414 			ret->ignore = TRUE;
    415 			return NULL;
    416 		}
    417 		data->in_op_code = op_code;
    418 		wpabuf_put_data(data->in_buf, buf, len);
    419 		wpa_printf(MSG_DEBUG, "EAP-WSC: Received %lu bytes in first "
    420 			   "fragment, waiting for %lu bytes more",
    421 			   (unsigned long) len,
    422 			   (unsigned long) wpabuf_tailroom(data->in_buf));
    423 	}
    424 
    425 	return eap_wsc_build_frag_ack(id, EAP_CODE_RESPONSE);
    426 }
    427 
    428 
    429 static struct wpabuf * eap_wsc_process(struct eap_sm *sm, void *priv,
    430 				       struct eap_method_ret *ret,
    431 				       const struct wpabuf *reqData)
    432 {
    433 	struct eap_wsc_data *data = priv;
    434 	const u8 *start, *pos, *end;
    435 	size_t len;
    436 	u8 op_code, flags, id;
    437 	u16 message_length = 0;
    438 	enum wps_process_res res;
    439 	struct wpabuf tmpbuf;
    440 	struct wpabuf *r;
    441 
    442 	pos = eap_hdr_validate(EAP_VENDOR_WFA, EAP_VENDOR_TYPE_WSC, reqData,
    443 			       &len);
    444 	if (pos == NULL || len < 2) {
    445 		ret->ignore = TRUE;
    446 		return NULL;
    447 	}
    448 
    449 	id = eap_get_id(reqData);
    450 
    451 	start = pos;
    452 	end = start + len;
    453 
    454 	op_code = *pos++;
    455 	flags = *pos++;
    456 	if (flags & WSC_FLAGS_LF) {
    457 		if (end - pos < 2) {
    458 			wpa_printf(MSG_DEBUG, "EAP-WSC: Message underflow");
    459 			ret->ignore = TRUE;
    460 			return NULL;
    461 		}
    462 		message_length = WPA_GET_BE16(pos);
    463 		pos += 2;
    464 
    465 		if (message_length < end - pos) {
    466 			wpa_printf(MSG_DEBUG, "EAP-WSC: Invalid Message "
    467 				   "Length");
    468 			ret->ignore = TRUE;
    469 			return NULL;
    470 		}
    471 	}
    472 
    473 	wpa_printf(MSG_DEBUG, "EAP-WSC: Received packet: Op-Code %d "
    474 		   "Flags 0x%x Message Length %d",
    475 		   op_code, flags, message_length);
    476 
    477 	if (data->state == WAIT_FRAG_ACK) {
    478 		if (op_code != WSC_FRAG_ACK) {
    479 			wpa_printf(MSG_DEBUG, "EAP-WSC: Unexpected Op-Code %d "
    480 				   "in WAIT_FRAG_ACK state", op_code);
    481 			ret->ignore = TRUE;
    482 			return NULL;
    483 		}
    484 		wpa_printf(MSG_DEBUG, "EAP-WSC: Fragment acknowledged");
    485 		eap_wsc_state(data, MESG);
    486 		return eap_wsc_build_msg(data, ret, id);
    487 	}
    488 
    489 	if (op_code != WSC_ACK && op_code != WSC_NACK && op_code != WSC_MSG &&
    490 	    op_code != WSC_Done && op_code != WSC_Start) {
    491 		wpa_printf(MSG_DEBUG, "EAP-WSC: Unexpected Op-Code %d",
    492 			   op_code);
    493 		ret->ignore = TRUE;
    494 		return NULL;
    495 	}
    496 
    497 	if (data->state == WAIT_START) {
    498 		if (op_code != WSC_Start) {
    499 			wpa_printf(MSG_DEBUG, "EAP-WSC: Unexpected Op-Code %d "
    500 				   "in WAIT_START state", op_code);
    501 			ret->ignore = TRUE;
    502 			return NULL;
    503 		}
    504 		wpa_printf(MSG_DEBUG, "EAP-WSC: Received start");
    505 		eap_wsc_state(data, MESG);
    506 		/* Start message has empty payload, skip processing */
    507 		goto send_msg;
    508 	} else if (op_code == WSC_Start) {
    509 		wpa_printf(MSG_DEBUG, "EAP-WSC: Unexpected Op-Code %d",
    510 			   op_code);
    511 		ret->ignore = TRUE;
    512 		return NULL;
    513 	}
    514 
    515 	if (data->in_buf &&
    516 	    eap_wsc_process_cont(data, pos, end - pos, op_code) < 0) {
    517 		ret->ignore = TRUE;
    518 		return NULL;
    519 	}
    520 
    521 	if (flags & WSC_FLAGS_MF) {
    522 		return eap_wsc_process_fragment(data, ret, id, flags, op_code,
    523 						message_length, pos,
    524 						end - pos);
    525 	}
    526 
    527 	if (data->in_buf == NULL) {
    528 		/* Wrap unfragmented messages as wpabuf without extra copy */
    529 		wpabuf_set(&tmpbuf, pos, end - pos);
    530 		data->in_buf = &tmpbuf;
    531 	}
    532 
    533 	res = wps_process_msg(data->wps, op_code, data->in_buf);
    534 	switch (res) {
    535 	case WPS_DONE:
    536 		wpa_printf(MSG_DEBUG, "EAP-WSC: WPS processing completed "
    537 			   "successfully - wait for EAP failure");
    538 		eap_wsc_state(data, FAIL);
    539 		break;
    540 	case WPS_CONTINUE:
    541 		eap_wsc_state(data, MESG);
    542 		break;
    543 	case WPS_FAILURE:
    544 	case WPS_PENDING:
    545 		wpa_printf(MSG_DEBUG, "EAP-WSC: WPS processing failed");
    546 		eap_wsc_state(data, FAIL);
    547 		break;
    548 	}
    549 
    550 	if (data->in_buf != &tmpbuf)
    551 		wpabuf_free(data->in_buf);
    552 	data->in_buf = NULL;
    553 
    554 send_msg:
    555 	if (data->out_buf == NULL) {
    556 		data->out_buf = wps_get_msg(data->wps, &data->out_op_code);
    557 		if (data->out_buf == NULL) {
    558 			wpa_printf(MSG_DEBUG, "EAP-WSC: Failed to receive "
    559 				   "message from WPS");
    560 			return NULL;
    561 		}
    562 		data->out_used = 0;
    563 	}
    564 
    565 	eap_wsc_state(data, MESG);
    566 	r = eap_wsc_build_msg(data, ret, id);
    567 	if (data->state == FAIL && ret->methodState == METHOD_DONE) {
    568 		/* Use reduced client timeout for WPS to avoid long wait */
    569 		if (sm->ClientTimeout > 2)
    570 			sm->ClientTimeout = 2;
    571 	}
    572 	return r;
    573 }
    574 
    575 
    576 int eap_peer_wsc_register(void)
    577 {
    578 	struct eap_method *eap;
    579 	int ret;
    580 
    581 	eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
    582 				    EAP_VENDOR_WFA, EAP_VENDOR_TYPE_WSC,
    583 				    "WSC");
    584 	if (eap == NULL)
    585 		return -1;
    586 
    587 	eap->init = eap_wsc_init;
    588 	eap->deinit = eap_wsc_deinit;
    589 	eap->process = eap_wsc_process;
    590 
    591 	ret = eap_peer_method_register(eap);
    592 	if (ret)
    593 		eap_peer_method_free(eap);
    594 	return ret;
    595 }
    596