Home | History | Annotate | Download | only in eap_server
      1 /*
      2  * EAP-WSC server for Wi-Fi Protected Setup
      3  * Copyright (c) 2007-2008, 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 "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
     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 
     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 
     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 
     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 
    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 
    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 
    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 
    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 		/* pass 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 
    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 
    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 
    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 
    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) {
    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 
    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 
    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 
    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 
    488 int eap_server_wsc_register(void)
    489 {
    490 	struct eap_method *eap;
    491 	int ret;
    492 
    493 	eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION,
    494 				      EAP_VENDOR_WFA, EAP_VENDOR_TYPE_WSC,
    495 				      "WSC");
    496 	if (eap == NULL)
    497 		return -1;
    498 
    499 	eap->init = eap_wsc_init;
    500 	eap->reset = eap_wsc_reset;
    501 	eap->buildReq = eap_wsc_buildReq;
    502 	eap->check = eap_wsc_check;
    503 	eap->process = eap_wsc_process;
    504 	eap->isDone = eap_wsc_isDone;
    505 	eap->isSuccess = eap_wsc_isSuccess;
    506 	eap->getTimeout = eap_wsc_getTimeout;
    507 
    508 	ret = eap_server_method_register(eap);
    509 	if (ret)
    510 		eap_server_method_free(eap);
    511 	return ret;
    512 }
    513