xref: /freebsd/contrib/wpa/src/wps/wps_common.c (revision 7661de35d15f582ab33e3bd6b8d909601557e436)
1 /*
2  * Wi-Fi Protected Setup - common functionality
3  * Copyright (c) 2008-2012, 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 "crypto/aes_wrap.h"
13 #include "crypto/crypto.h"
14 #include "crypto/dh_group5.h"
15 #include "crypto/sha1.h"
16 #include "crypto/sha256.h"
17 #include "crypto/random.h"
18 #include "wps_i.h"
19 
20 
21 void wps_kdf(const u8 *key, const u8 *label_prefix, size_t label_prefix_len,
22 	     const char *label, u8 *res, size_t res_len)
23 {
24 	u8 i_buf[4], key_bits[4];
25 	const u8 *addr[4];
26 	size_t len[4];
27 	int i, iter;
28 	u8 hash[SHA256_MAC_LEN], *opos;
29 	size_t left;
30 
31 	WPA_PUT_BE32(key_bits, res_len * 8);
32 
33 	addr[0] = i_buf;
34 	len[0] = sizeof(i_buf);
35 	addr[1] = label_prefix;
36 	len[1] = label_prefix_len;
37 	addr[2] = (const u8 *) label;
38 	len[2] = os_strlen(label);
39 	addr[3] = key_bits;
40 	len[3] = sizeof(key_bits);
41 
42 	iter = (res_len + SHA256_MAC_LEN - 1) / SHA256_MAC_LEN;
43 	opos = res;
44 	left = res_len;
45 
46 	for (i = 1; i <= iter; i++) {
47 		WPA_PUT_BE32(i_buf, i);
48 		hmac_sha256_vector(key, SHA256_MAC_LEN, 4, addr, len, hash);
49 		if (i < iter) {
50 			os_memcpy(opos, hash, SHA256_MAC_LEN);
51 			opos += SHA256_MAC_LEN;
52 			left -= SHA256_MAC_LEN;
53 		} else
54 			os_memcpy(opos, hash, left);
55 	}
56 }
57 
58 
59 int wps_derive_keys(struct wps_data *wps)
60 {
61 	struct wpabuf *pubkey, *dh_shared;
62 	u8 dhkey[SHA256_MAC_LEN], kdk[SHA256_MAC_LEN];
63 	const u8 *addr[3];
64 	size_t len[3];
65 	u8 keys[WPS_AUTHKEY_LEN + WPS_KEYWRAPKEY_LEN + WPS_EMSK_LEN];
66 
67 	if (wps->dh_privkey == NULL) {
68 		wpa_printf(MSG_DEBUG, "WPS: Own DH private key not available");
69 		return -1;
70 	}
71 
72 	pubkey = wps->registrar ? wps->dh_pubkey_e : wps->dh_pubkey_r;
73 	if (pubkey == NULL) {
74 		wpa_printf(MSG_DEBUG, "WPS: Peer DH public key not available");
75 		return -1;
76 	}
77 
78 	wpa_hexdump_buf_key(MSG_DEBUG, "WPS: DH Private Key", wps->dh_privkey);
79 	wpa_hexdump_buf(MSG_DEBUG, "WPS: DH peer Public Key", pubkey);
80 	dh_shared = dh5_derive_shared(wps->dh_ctx, pubkey, wps->dh_privkey);
81 	dh5_free(wps->dh_ctx);
82 	wps->dh_ctx = NULL;
83 	dh_shared = wpabuf_zeropad(dh_shared, 192);
84 	if (dh_shared == NULL) {
85 		wpa_printf(MSG_DEBUG, "WPS: Failed to derive DH shared key");
86 		return -1;
87 	}
88 
89 	/* Own DH private key is not needed anymore */
90 	wpabuf_free(wps->dh_privkey);
91 	wps->dh_privkey = NULL;
92 
93 	wpa_hexdump_buf_key(MSG_DEBUG, "WPS: DH shared key", dh_shared);
94 
95 	/* DHKey = SHA-256(g^AB mod p) */
96 	addr[0] = wpabuf_head(dh_shared);
97 	len[0] = wpabuf_len(dh_shared);
98 	sha256_vector(1, addr, len, dhkey);
99 	wpa_hexdump_key(MSG_DEBUG, "WPS: DHKey", dhkey, sizeof(dhkey));
100 	wpabuf_free(dh_shared);
101 
102 	/* KDK = HMAC-SHA-256_DHKey(N1 || EnrolleeMAC || N2) */
103 	addr[0] = wps->nonce_e;
104 	len[0] = WPS_NONCE_LEN;
105 	addr[1] = wps->mac_addr_e;
106 	len[1] = ETH_ALEN;
107 	addr[2] = wps->nonce_r;
108 	len[2] = WPS_NONCE_LEN;
109 	hmac_sha256_vector(dhkey, sizeof(dhkey), 3, addr, len, kdk);
110 	wpa_hexdump_key(MSG_DEBUG, "WPS: KDK", kdk, sizeof(kdk));
111 
112 	wps_kdf(kdk, NULL, 0, "Wi-Fi Easy and Secure Key Derivation",
113 		keys, sizeof(keys));
114 	os_memcpy(wps->authkey, keys, WPS_AUTHKEY_LEN);
115 	os_memcpy(wps->keywrapkey, keys + WPS_AUTHKEY_LEN, WPS_KEYWRAPKEY_LEN);
116 	os_memcpy(wps->emsk, keys + WPS_AUTHKEY_LEN + WPS_KEYWRAPKEY_LEN,
117 		  WPS_EMSK_LEN);
118 
119 	wpa_hexdump_key(MSG_DEBUG, "WPS: AuthKey",
120 			wps->authkey, WPS_AUTHKEY_LEN);
121 	wpa_hexdump_key(MSG_DEBUG, "WPS: KeyWrapKey",
122 			wps->keywrapkey, WPS_KEYWRAPKEY_LEN);
123 	wpa_hexdump_key(MSG_DEBUG, "WPS: EMSK", wps->emsk, WPS_EMSK_LEN);
124 
125 	return 0;
126 }
127 
128 
129 void wps_derive_psk(struct wps_data *wps, const u8 *dev_passwd,
130 		    size_t dev_passwd_len)
131 {
132 	u8 hash[SHA256_MAC_LEN];
133 
134 	hmac_sha256(wps->authkey, WPS_AUTHKEY_LEN, dev_passwd,
135 		    (dev_passwd_len + 1) / 2, hash);
136 	os_memcpy(wps->psk1, hash, WPS_PSK_LEN);
137 	hmac_sha256(wps->authkey, WPS_AUTHKEY_LEN,
138 		    dev_passwd + (dev_passwd_len + 1) / 2,
139 		    dev_passwd_len / 2, hash);
140 	os_memcpy(wps->psk2, hash, WPS_PSK_LEN);
141 
142 	wpa_hexdump_ascii_key(MSG_DEBUG, "WPS: Device Password",
143 			      dev_passwd, dev_passwd_len);
144 	wpa_hexdump_key(MSG_DEBUG, "WPS: PSK1", wps->psk1, WPS_PSK_LEN);
145 	wpa_hexdump_key(MSG_DEBUG, "WPS: PSK2", wps->psk2, WPS_PSK_LEN);
146 }
147 
148 
149 struct wpabuf * wps_decrypt_encr_settings(struct wps_data *wps, const u8 *encr,
150 					  size_t encr_len)
151 {
152 	struct wpabuf *decrypted;
153 	const size_t block_size = 16;
154 	size_t i;
155 	u8 pad;
156 	const u8 *pos;
157 
158 	/* AES-128-CBC */
159 	if (encr == NULL || encr_len < 2 * block_size || encr_len % block_size)
160 	{
161 		wpa_printf(MSG_DEBUG, "WPS: No Encrypted Settings received");
162 		return NULL;
163 	}
164 
165 	decrypted = wpabuf_alloc(encr_len - block_size);
166 	if (decrypted == NULL)
167 		return NULL;
168 
169 	wpa_hexdump(MSG_MSGDUMP, "WPS: Encrypted Settings", encr, encr_len);
170 	wpabuf_put_data(decrypted, encr + block_size, encr_len - block_size);
171 	if (aes_128_cbc_decrypt(wps->keywrapkey, encr, wpabuf_mhead(decrypted),
172 				wpabuf_len(decrypted))) {
173 		wpabuf_free(decrypted);
174 		return NULL;
175 	}
176 
177 	wpa_hexdump_buf_key(MSG_MSGDUMP, "WPS: Decrypted Encrypted Settings",
178 			    decrypted);
179 
180 	pos = wpabuf_head_u8(decrypted) + wpabuf_len(decrypted) - 1;
181 	pad = *pos;
182 	if (pad > wpabuf_len(decrypted)) {
183 		wpa_printf(MSG_DEBUG, "WPS: Invalid PKCS#5 v2.0 pad value");
184 		wpabuf_free(decrypted);
185 		return NULL;
186 	}
187 	for (i = 0; i < pad; i++) {
188 		if (*pos-- != pad) {
189 			wpa_printf(MSG_DEBUG, "WPS: Invalid PKCS#5 v2.0 pad "
190 				   "string");
191 			wpabuf_free(decrypted);
192 			return NULL;
193 		}
194 	}
195 	decrypted->used -= pad;
196 
197 	return decrypted;
198 }
199 
200 
201 /**
202  * wps_pin_checksum - Compute PIN checksum
203  * @pin: Seven digit PIN (i.e., eight digit PIN without the checksum digit)
204  * Returns: Checksum digit
205  */
206 unsigned int wps_pin_checksum(unsigned int pin)
207 {
208 	unsigned int accum = 0;
209 	while (pin) {
210 		accum += 3 * (pin % 10);
211 		pin /= 10;
212 		accum += pin % 10;
213 		pin /= 10;
214 	}
215 
216 	return (10 - accum % 10) % 10;
217 }
218 
219 
220 /**
221  * wps_pin_valid - Check whether a PIN has a valid checksum
222  * @pin: Eight digit PIN (i.e., including the checksum digit)
223  * Returns: 1 if checksum digit is valid, or 0 if not
224  */
225 unsigned int wps_pin_valid(unsigned int pin)
226 {
227 	return wps_pin_checksum(pin / 10) == (pin % 10);
228 }
229 
230 
231 /**
232  * wps_generate_pin - Generate a random PIN
233  * Returns: Eight digit PIN (i.e., including the checksum digit)
234  */
235 unsigned int wps_generate_pin(void)
236 {
237 	unsigned int val;
238 
239 	/* Generate seven random digits for the PIN */
240 	if (random_get_bytes((unsigned char *) &val, sizeof(val)) < 0) {
241 		struct os_time now;
242 		os_get_time(&now);
243 		val = os_random() ^ now.sec ^ now.usec;
244 	}
245 	val %= 10000000;
246 
247 	/* Append checksum digit */
248 	return val * 10 + wps_pin_checksum(val);
249 }
250 
251 
252 int wps_pin_str_valid(const char *pin)
253 {
254 	const char *p;
255 	size_t len;
256 
257 	p = pin;
258 	while (*p >= '0' && *p <= '9')
259 		p++;
260 	if (*p != '\0')
261 		return 0;
262 
263 	len = p - pin;
264 	return len == 4 || len == 8;
265 }
266 
267 
268 void wps_fail_event(struct wps_context *wps, enum wps_msg_type msg,
269 		    u16 config_error, u16 error_indication)
270 {
271 	union wps_event_data data;
272 
273 	if (wps->event_cb == NULL)
274 		return;
275 
276 	os_memset(&data, 0, sizeof(data));
277 	data.fail.msg = msg;
278 	data.fail.config_error = config_error;
279 	data.fail.error_indication = error_indication;
280 	wps->event_cb(wps->cb_ctx, WPS_EV_FAIL, &data);
281 }
282 
283 
284 void wps_success_event(struct wps_context *wps)
285 {
286 	if (wps->event_cb == NULL)
287 		return;
288 
289 	wps->event_cb(wps->cb_ctx, WPS_EV_SUCCESS, NULL);
290 }
291 
292 
293 void wps_pwd_auth_fail_event(struct wps_context *wps, int enrollee, int part)
294 {
295 	union wps_event_data data;
296 
297 	if (wps->event_cb == NULL)
298 		return;
299 
300 	os_memset(&data, 0, sizeof(data));
301 	data.pwd_auth_fail.enrollee = enrollee;
302 	data.pwd_auth_fail.part = part;
303 	wps->event_cb(wps->cb_ctx, WPS_EV_PWD_AUTH_FAIL, &data);
304 }
305 
306 
307 void wps_pbc_overlap_event(struct wps_context *wps)
308 {
309 	if (wps->event_cb == NULL)
310 		return;
311 
312 	wps->event_cb(wps->cb_ctx, WPS_EV_PBC_OVERLAP, NULL);
313 }
314 
315 
316 void wps_pbc_timeout_event(struct wps_context *wps)
317 {
318 	if (wps->event_cb == NULL)
319 		return;
320 
321 	wps->event_cb(wps->cb_ctx, WPS_EV_PBC_TIMEOUT, NULL);
322 }
323 
324 
325 #ifdef CONFIG_WPS_OOB
326 
327 struct wpabuf * wps_get_oob_cred(struct wps_context *wps)
328 {
329 	struct wps_data data;
330 	struct wpabuf *plain;
331 
332 	plain = wpabuf_alloc(500);
333 	if (plain == NULL) {
334 		wpa_printf(MSG_ERROR, "WPS: Failed to allocate memory for OOB "
335 			   "credential");
336 		return NULL;
337 	}
338 
339 	os_memset(&data, 0, sizeof(data));
340 	data.wps = wps;
341 	data.auth_type = wps->auth_types;
342 	data.encr_type = wps->encr_types;
343 	if (wps_build_version(plain) ||
344 	    wps_build_cred(&data, plain) ||
345 	    wps_build_wfa_ext(plain, 0, NULL, 0)) {
346 		wpabuf_free(plain);
347 		return NULL;
348 	}
349 
350 	return plain;
351 }
352 
353 
354 struct wpabuf * wps_build_nfc_pw_token(u16 dev_pw_id,
355 				       const struct wpabuf *pubkey,
356 				       const struct wpabuf *dev_pw)
357 {
358 	struct wpabuf *data;
359 
360 	data = wpabuf_alloc(200);
361 	if (data == NULL)
362 		return NULL;
363 
364 	if (wps_build_version(data) ||
365 	    wps_build_oob_dev_pw(data, dev_pw_id, pubkey,
366 				 wpabuf_head(dev_pw), wpabuf_len(dev_pw)) ||
367 	    wps_build_wfa_ext(data, 0, NULL, 0)) {
368 		wpa_printf(MSG_ERROR, "WPS: Failed to build NFC password "
369 			   "token");
370 		wpabuf_free(data);
371 		return NULL;
372 	}
373 
374 	return data;
375 }
376 
377 
378 int wps_oob_use_cred(struct wps_context *wps, struct wps_parse_attr *attr)
379 {
380 	struct wpabuf msg;
381 	size_t i;
382 
383 	for (i = 0; i < attr->num_cred; i++) {
384 		struct wps_credential local_cred;
385 		struct wps_parse_attr cattr;
386 
387 		os_memset(&local_cred, 0, sizeof(local_cred));
388 		wpabuf_set(&msg, attr->cred[i], attr->cred_len[i]);
389 		if (wps_parse_msg(&msg, &cattr) < 0 ||
390 		    wps_process_cred(&cattr, &local_cred)) {
391 			wpa_printf(MSG_ERROR, "WPS: Failed to parse OOB "
392 				   "credential");
393 			return -1;
394 		}
395 		wps->cred_cb(wps->cb_ctx, &local_cred);
396 	}
397 
398 	return 0;
399 }
400 
401 
402 #endif /* CONFIG_WPS_OOB */
403 
404 
405 int wps_dev_type_str2bin(const char *str, u8 dev_type[WPS_DEV_TYPE_LEN])
406 {
407 	const char *pos;
408 
409 	/* <categ>-<OUI>-<subcateg> */
410 	WPA_PUT_BE16(dev_type, atoi(str));
411 	pos = os_strchr(str, '-');
412 	if (pos == NULL)
413 		return -1;
414 	pos++;
415 	if (hexstr2bin(pos, &dev_type[2], 4))
416 		return -1;
417 	pos = os_strchr(pos, '-');
418 	if (pos == NULL)
419 		return -1;
420 	pos++;
421 	WPA_PUT_BE16(&dev_type[6], atoi(pos));
422 
423 
424 	return 0;
425 }
426 
427 
428 char * wps_dev_type_bin2str(const u8 dev_type[WPS_DEV_TYPE_LEN], char *buf,
429 			    size_t buf_len)
430 {
431 	int ret;
432 
433 	ret = os_snprintf(buf, buf_len, "%u-%08X-%u",
434 			  WPA_GET_BE16(dev_type), WPA_GET_BE32(&dev_type[2]),
435 			  WPA_GET_BE16(&dev_type[6]));
436 	if (ret < 0 || (unsigned int) ret >= buf_len)
437 		return NULL;
438 
439 	return buf;
440 }
441 
442 
443 void uuid_gen_mac_addr(const u8 *mac_addr, u8 *uuid)
444 {
445 	const u8 *addr[2];
446 	size_t len[2];
447 	u8 hash[SHA1_MAC_LEN];
448 	u8 nsid[16] = {
449 		0x52, 0x64, 0x80, 0xf8,
450 		0xc9, 0x9b,
451 		0x4b, 0xe5,
452 		0xa6, 0x55,
453 		0x58, 0xed, 0x5f, 0x5d, 0x60, 0x84
454 	};
455 
456 	addr[0] = nsid;
457 	len[0] = sizeof(nsid);
458 	addr[1] = mac_addr;
459 	len[1] = 6;
460 	sha1_vector(2, addr, len, hash);
461 	os_memcpy(uuid, hash, 16);
462 
463 	/* Version: 5 = named-based version using SHA-1 */
464 	uuid[6] = (5 << 4) | (uuid[6] & 0x0f);
465 
466 	/* Variant specified in RFC 4122 */
467 	uuid[8] = 0x80 | (uuid[8] & 0x3f);
468 }
469 
470 
471 u16 wps_config_methods_str2bin(const char *str)
472 {
473 	u16 methods = 0;
474 
475 	if (str == NULL) {
476 		/* Default to enabling methods based on build configuration */
477 		methods |= WPS_CONFIG_DISPLAY | WPS_CONFIG_KEYPAD;
478 #ifdef CONFIG_WPS2
479 		methods |= WPS_CONFIG_VIRT_DISPLAY;
480 #endif /* CONFIG_WPS2 */
481 #ifdef CONFIG_WPS_NFC
482 		methods |= WPS_CONFIG_NFC_INTERFACE;
483 #endif /* CONFIG_WPS_NFC */
484 	} else {
485 		if (os_strstr(str, "ethernet"))
486 			methods |= WPS_CONFIG_ETHERNET;
487 		if (os_strstr(str, "label"))
488 			methods |= WPS_CONFIG_LABEL;
489 		if (os_strstr(str, "display"))
490 			methods |= WPS_CONFIG_DISPLAY;
491 		if (os_strstr(str, "ext_nfc_token"))
492 			methods |= WPS_CONFIG_EXT_NFC_TOKEN;
493 		if (os_strstr(str, "int_nfc_token"))
494 			methods |= WPS_CONFIG_INT_NFC_TOKEN;
495 		if (os_strstr(str, "nfc_interface"))
496 			methods |= WPS_CONFIG_NFC_INTERFACE;
497 		if (os_strstr(str, "push_button"))
498 			methods |= WPS_CONFIG_PUSHBUTTON;
499 		if (os_strstr(str, "keypad"))
500 			methods |= WPS_CONFIG_KEYPAD;
501 #ifdef CONFIG_WPS2
502 		if (os_strstr(str, "virtual_display"))
503 			methods |= WPS_CONFIG_VIRT_DISPLAY;
504 		if (os_strstr(str, "physical_display"))
505 			methods |= WPS_CONFIG_PHY_DISPLAY;
506 		if (os_strstr(str, "virtual_push_button"))
507 			methods |= WPS_CONFIG_VIRT_PUSHBUTTON;
508 		if (os_strstr(str, "physical_push_button"))
509 			methods |= WPS_CONFIG_PHY_PUSHBUTTON;
510 #endif /* CONFIG_WPS2 */
511 	}
512 
513 	return methods;
514 }
515 
516 
517 struct wpabuf * wps_build_wsc_ack(struct wps_data *wps)
518 {
519 	struct wpabuf *msg;
520 
521 	wpa_printf(MSG_DEBUG, "WPS: Building Message WSC_ACK");
522 
523 	msg = wpabuf_alloc(1000);
524 	if (msg == NULL)
525 		return NULL;
526 
527 	if (wps_build_version(msg) ||
528 	    wps_build_msg_type(msg, WPS_WSC_ACK) ||
529 	    wps_build_enrollee_nonce(wps, msg) ||
530 	    wps_build_registrar_nonce(wps, msg) ||
531 	    wps_build_wfa_ext(msg, 0, NULL, 0)) {
532 		wpabuf_free(msg);
533 		return NULL;
534 	}
535 
536 	return msg;
537 }
538 
539 
540 struct wpabuf * wps_build_wsc_nack(struct wps_data *wps)
541 {
542 	struct wpabuf *msg;
543 
544 	wpa_printf(MSG_DEBUG, "WPS: Building Message WSC_NACK");
545 
546 	msg = wpabuf_alloc(1000);
547 	if (msg == NULL)
548 		return NULL;
549 
550 	if (wps_build_version(msg) ||
551 	    wps_build_msg_type(msg, WPS_WSC_NACK) ||
552 	    wps_build_enrollee_nonce(wps, msg) ||
553 	    wps_build_registrar_nonce(wps, msg) ||
554 	    wps_build_config_error(msg, wps->config_error) ||
555 	    wps_build_wfa_ext(msg, 0, NULL, 0)) {
556 		wpabuf_free(msg);
557 		return NULL;
558 	}
559 
560 	return msg;
561 }
562 
563 
564 #ifdef CONFIG_WPS_NFC
565 struct wpabuf * wps_nfc_token_gen(int ndef, int *id, struct wpabuf **pubkey,
566 				  struct wpabuf **privkey,
567 				  struct wpabuf **dev_pw)
568 {
569 	struct wpabuf *priv = NULL, *pub = NULL, *pw, *ret;
570 	void *dh_ctx;
571 	u16 val;
572 
573 	pw = wpabuf_alloc(WPS_OOB_DEVICE_PASSWORD_LEN);
574 	if (pw == NULL)
575 		return NULL;
576 
577 	if (random_get_bytes(wpabuf_put(pw, WPS_OOB_DEVICE_PASSWORD_LEN),
578 			     WPS_OOB_DEVICE_PASSWORD_LEN) ||
579 	    random_get_bytes((u8 *) &val, sizeof(val))) {
580 		wpabuf_free(pw);
581 		return NULL;
582 	}
583 
584 	dh_ctx = dh5_init(&priv, &pub);
585 	if (dh_ctx == NULL) {
586 		wpabuf_free(pw);
587 		return NULL;
588 	}
589 	dh5_free(dh_ctx);
590 
591 	*id = 0x10 + val % 0xfff0;
592 	wpabuf_free(*pubkey);
593 	*pubkey = pub;
594 	wpabuf_free(*privkey);
595 	*privkey = priv;
596 	wpabuf_free(*dev_pw);
597 	*dev_pw = pw;
598 
599 	ret = wps_build_nfc_pw_token(*id, *pubkey, *dev_pw);
600 	if (ndef && ret) {
601 		struct wpabuf *tmp;
602 		tmp = ndef_build_wifi(ret);
603 		wpabuf_free(ret);
604 		if (tmp == NULL)
605 			return NULL;
606 		ret = tmp;
607 	}
608 
609 	return ret;
610 }
611 #endif /* CONFIG_WPS_NFC */
612