wps_attr_build.c revision 337817 
1/*
2 * Wi-Fi Protected Setup - attribute building
3 * Copyright (c) 2008-2016, 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/sha256.h"
16#include "crypto/random.h"
17#include "common/ieee802_11_defs.h"
18#include "wps_i.h"
19
20
21int wps_build_public_key(struct wps_data *wps, struct wpabuf *msg)
22{
23	struct wpabuf *pubkey = NULL;
24
25	wpa_printf(MSG_DEBUG, "WPS:  * Public Key");
26	wpabuf_clear_free(wps->dh_privkey);
27	wps->dh_privkey = NULL;
28	if (wps->dev_pw_id != DEV_PW_DEFAULT && wps->wps->dh_privkey &&
29	    wps->wps->dh_ctx) {
30		wpa_printf(MSG_DEBUG, "WPS: Using pre-configured DH keys");
31		if (wps->wps->dh_pubkey == NULL) {
32			wpa_printf(MSG_DEBUG,
33				   "WPS: wps->wps->dh_pubkey == NULL");
34			return -1;
35		}
36		wps->dh_privkey = wpabuf_dup(wps->wps->dh_privkey);
37		wps->dh_ctx = wps->wps->dh_ctx;
38		wps->wps->dh_ctx = NULL;
39		pubkey = wpabuf_dup(wps->wps->dh_pubkey);
40#ifdef CONFIG_WPS_NFC
41	} else if ((wps->dev_pw_id >= 0x10 ||
42		    wps->dev_pw_id == DEV_PW_NFC_CONNECTION_HANDOVER) &&
43		   (wps->wps->ap ||
44		    (wps->wps->ap_nfc_dh_pubkey &&
45		     wps->wps->ap_nfc_dev_pw_id ==
46		     DEV_PW_NFC_CONNECTION_HANDOVER &&
47		     wps->dev_pw_id == DEV_PW_NFC_CONNECTION_HANDOVER)) &&
48		   (wps->dev_pw_id == wps->wps->ap_nfc_dev_pw_id ||
49		    wps->wps->ap_nfc_dh_pubkey)) {
50		wpa_printf(MSG_DEBUG, "WPS: Using NFC password token DH keys");
51		if (wps->wps->ap_nfc_dh_privkey == NULL) {
52			wpa_printf(MSG_DEBUG,
53				   "WPS: wps->wps->ap_nfc_dh_privkey == NULL");
54			return -1;
55		}
56		if (wps->wps->ap_nfc_dh_pubkey == NULL) {
57			wpa_printf(MSG_DEBUG,
58				   "WPS: wps->wps->ap_nfc_dh_pubkey == NULL");
59			return -1;
60		}
61		wps->dh_privkey = wpabuf_dup(wps->wps->ap_nfc_dh_privkey);
62		pubkey = wpabuf_dup(wps->wps->ap_nfc_dh_pubkey);
63		wps->dh_ctx = dh5_init_fixed(wps->dh_privkey, pubkey);
64#endif /* CONFIG_WPS_NFC */
65	} else {
66		wpa_printf(MSG_DEBUG, "WPS: Generate new DH keys");
67		dh5_free(wps->dh_ctx);
68		wps->dh_ctx = dh5_init(&wps->dh_privkey, &pubkey);
69		pubkey = wpabuf_zeropad(pubkey, 192);
70	}
71	if (wps->dh_ctx == NULL || wps->dh_privkey == NULL || pubkey == NULL) {
72		wpa_printf(MSG_DEBUG, "WPS: Failed to initialize "
73			   "Diffie-Hellman handshake");
74		wpabuf_free(pubkey);
75		return -1;
76	}
77	wpa_hexdump_buf_key(MSG_DEBUG, "WPS: DH Private Key", wps->dh_privkey);
78	wpa_hexdump_buf(MSG_DEBUG, "WPS: DH own Public Key", pubkey);
79
80	wpabuf_put_be16(msg, ATTR_PUBLIC_KEY);
81	wpabuf_put_be16(msg, wpabuf_len(pubkey));
82	wpabuf_put_buf(msg, pubkey);
83
84	if (wps->registrar) {
85		wpabuf_free(wps->dh_pubkey_r);
86		wps->dh_pubkey_r = pubkey;
87	} else {
88		wpabuf_free(wps->dh_pubkey_e);
89		wps->dh_pubkey_e = pubkey;
90	}
91
92	return 0;
93}
94
95
96int wps_build_req_type(struct wpabuf *msg, enum wps_request_type type)
97{
98	wpa_printf(MSG_DEBUG, "WPS:  * Request Type");
99	wpabuf_put_be16(msg, ATTR_REQUEST_TYPE);
100	wpabuf_put_be16(msg, 1);
101	wpabuf_put_u8(msg, type);
102	return 0;
103}
104
105
106int wps_build_resp_type(struct wpabuf *msg, enum wps_response_type type)
107{
108	wpa_printf(MSG_DEBUG, "WPS:  * Response Type (%d)", type);
109	wpabuf_put_be16(msg, ATTR_RESPONSE_TYPE);
110	wpabuf_put_be16(msg, 1);
111	wpabuf_put_u8(msg, type);
112	return 0;
113}
114
115
116int wps_build_config_methods(struct wpabuf *msg, u16 methods)
117{
118	wpa_printf(MSG_DEBUG, "WPS:  * Config Methods (%x)", methods);
119	wpabuf_put_be16(msg, ATTR_CONFIG_METHODS);
120	wpabuf_put_be16(msg, 2);
121	wpabuf_put_be16(msg, methods);
122	return 0;
123}
124
125
126int wps_build_uuid_e(struct wpabuf *msg, const u8 *uuid)
127{
128	if (wpabuf_tailroom(msg) < 4 + WPS_UUID_LEN)
129		return -1;
130	wpa_printf(MSG_DEBUG, "WPS:  * UUID-E");
131	wpabuf_put_be16(msg, ATTR_UUID_E);
132	wpabuf_put_be16(msg, WPS_UUID_LEN);
133	wpabuf_put_data(msg, uuid, WPS_UUID_LEN);
134	return 0;
135}
136
137
138int wps_build_dev_password_id(struct wpabuf *msg, u16 id)
139{
140	wpa_printf(MSG_DEBUG, "WPS:  * Device Password ID (%d)", id);
141	wpabuf_put_be16(msg, ATTR_DEV_PASSWORD_ID);
142	wpabuf_put_be16(msg, 2);
143	wpabuf_put_be16(msg, id);
144	return 0;
145}
146
147
148int wps_build_config_error(struct wpabuf *msg, u16 err)
149{
150	wpa_printf(MSG_DEBUG, "WPS:  * Configuration Error (%d)", err);
151	wpabuf_put_be16(msg, ATTR_CONFIG_ERROR);
152	wpabuf_put_be16(msg, 2);
153	wpabuf_put_be16(msg, err);
154	return 0;
155}
156
157
158int wps_build_authenticator(struct wps_data *wps, struct wpabuf *msg)
159{
160	u8 hash[SHA256_MAC_LEN];
161	const u8 *addr[2];
162	size_t len[2];
163
164	if (wps->last_msg == NULL) {
165		wpa_printf(MSG_DEBUG, "WPS: Last message not available for "
166			   "building authenticator");
167		return -1;
168	}
169
170	/* Authenticator = HMAC-SHA256_AuthKey(M_prev || M_curr*)
171	 * (M_curr* is M_curr without the Authenticator attribute)
172	 */
173	addr[0] = wpabuf_head(wps->last_msg);
174	len[0] = wpabuf_len(wps->last_msg);
175	addr[1] = wpabuf_head(msg);
176	len[1] = wpabuf_len(msg);
177	hmac_sha256_vector(wps->authkey, WPS_AUTHKEY_LEN, 2, addr, len, hash);
178
179	wpa_printf(MSG_DEBUG, "WPS:  * Authenticator");
180	wpabuf_put_be16(msg, ATTR_AUTHENTICATOR);
181	wpabuf_put_be16(msg, WPS_AUTHENTICATOR_LEN);
182	wpabuf_put_data(msg, hash, WPS_AUTHENTICATOR_LEN);
183
184	return 0;
185}
186
187
188int wps_build_version(struct wpabuf *msg)
189{
190	/*
191	 * Note: This attribute is deprecated and set to hardcoded 0x10 for
192	 * backwards compatibility reasons. The real version negotiation is
193	 * done with Version2.
194	 */
195	if (wpabuf_tailroom(msg) < 5)
196		return -1;
197	wpa_printf(MSG_DEBUG, "WPS:  * Version (hardcoded 0x10)");
198	wpabuf_put_be16(msg, ATTR_VERSION);
199	wpabuf_put_be16(msg, 1);
200	wpabuf_put_u8(msg, 0x10);
201	return 0;
202}
203
204
205int wps_build_wfa_ext(struct wpabuf *msg, int req_to_enroll,
206		      const u8 *auth_macs, size_t auth_macs_count)
207{
208	u8 *len;
209
210#ifdef CONFIG_WPS_TESTING
211	if (WPS_VERSION == 0x10)
212		return 0;
213#endif /* CONFIG_WPS_TESTING */
214
215	if (wpabuf_tailroom(msg) <
216	    7 + 3 + (req_to_enroll ? 3 : 0) +
217	    (auth_macs ? 2 + auth_macs_count * ETH_ALEN : 0))
218		return -1;
219	wpabuf_put_be16(msg, ATTR_VENDOR_EXT);
220	len = wpabuf_put(msg, 2); /* to be filled */
221	wpabuf_put_be24(msg, WPS_VENDOR_ID_WFA);
222
223	wpa_printf(MSG_DEBUG, "WPS:  * Version2 (0x%x)", WPS_VERSION);
224	wpabuf_put_u8(msg, WFA_ELEM_VERSION2);
225	wpabuf_put_u8(msg, 1);
226	wpabuf_put_u8(msg, WPS_VERSION);
227
228	if (req_to_enroll) {
229		wpa_printf(MSG_DEBUG, "WPS:  * Request to Enroll (1)");
230		wpabuf_put_u8(msg, WFA_ELEM_REQUEST_TO_ENROLL);
231		wpabuf_put_u8(msg, 1);
232		wpabuf_put_u8(msg, 1);
233	}
234
235	if (auth_macs && auth_macs_count) {
236		size_t i;
237		wpa_printf(MSG_DEBUG, "WPS:  * AuthorizedMACs (count=%d)",
238			   (int) auth_macs_count);
239		wpabuf_put_u8(msg, WFA_ELEM_AUTHORIZEDMACS);
240		wpabuf_put_u8(msg, auth_macs_count * ETH_ALEN);
241		wpabuf_put_data(msg, auth_macs, auth_macs_count * ETH_ALEN);
242		for (i = 0; i < auth_macs_count; i++)
243			wpa_printf(MSG_DEBUG, "WPS:    AuthorizedMAC: " MACSTR,
244				   MAC2STR(&auth_macs[i * ETH_ALEN]));
245	}
246
247	WPA_PUT_BE16(len, (u8 *) wpabuf_put(msg, 0) - len - 2);
248
249#ifdef CONFIG_WPS_TESTING
250	if (WPS_VERSION > 0x20) {
251		if (wpabuf_tailroom(msg) < 5)
252			return -1;
253		wpa_printf(MSG_DEBUG, "WPS:  * Extensibility Testing - extra "
254			   "attribute");
255		wpabuf_put_be16(msg, ATTR_EXTENSIBILITY_TEST);
256		wpabuf_put_be16(msg, 1);
257		wpabuf_put_u8(msg, 42);
258	}
259#endif /* CONFIG_WPS_TESTING */
260	return 0;
261}
262
263
264int wps_build_msg_type(struct wpabuf *msg, enum wps_msg_type msg_type)
265{
266	wpa_printf(MSG_DEBUG, "WPS:  * Message Type (%d)", msg_type);
267	wpabuf_put_be16(msg, ATTR_MSG_TYPE);
268	wpabuf_put_be16(msg, 1);
269	wpabuf_put_u8(msg, msg_type);
270	return 0;
271}
272
273
274int wps_build_enrollee_nonce(struct wps_data *wps, struct wpabuf *msg)
275{
276	wpa_printf(MSG_DEBUG, "WPS:  * Enrollee Nonce");
277	wpabuf_put_be16(msg, ATTR_ENROLLEE_NONCE);
278	wpabuf_put_be16(msg, WPS_NONCE_LEN);
279	wpabuf_put_data(msg, wps->nonce_e, WPS_NONCE_LEN);
280	return 0;
281}
282
283
284int wps_build_registrar_nonce(struct wps_data *wps, struct wpabuf *msg)
285{
286	wpa_printf(MSG_DEBUG, "WPS:  * Registrar Nonce");
287	wpabuf_put_be16(msg, ATTR_REGISTRAR_NONCE);
288	wpabuf_put_be16(msg, WPS_NONCE_LEN);
289	wpabuf_put_data(msg, wps->nonce_r, WPS_NONCE_LEN);
290	return 0;
291}
292
293
294int wps_build_auth_type_flags(struct wps_data *wps, struct wpabuf *msg)
295{
296	u16 auth_types = WPS_AUTH_TYPES;
297	/* WPA/WPA2-Enterprise enrollment not supported through WPS */
298	auth_types &= ~WPS_AUTH_WPA;
299	auth_types &= ~WPS_AUTH_WPA2;
300	auth_types &= ~WPS_AUTH_SHARED;
301#ifdef CONFIG_WPS_TESTING
302	if (wps_force_auth_types_in_use) {
303		wpa_printf(MSG_DEBUG,
304			   "WPS: Testing - replace auth type 0x%x with 0x%x",
305			   auth_types, wps_force_auth_types);
306		auth_types = wps_force_auth_types;
307	}
308#endif /* CONFIG_WPS_TESTING */
309	wpa_printf(MSG_DEBUG, "WPS:  * Authentication Type Flags (0x%x)",
310		   auth_types);
311	wpabuf_put_be16(msg, ATTR_AUTH_TYPE_FLAGS);
312	wpabuf_put_be16(msg, 2);
313	wpabuf_put_be16(msg, auth_types);
314	return 0;
315}
316
317
318int wps_build_encr_type_flags(struct wps_data *wps, struct wpabuf *msg)
319{
320	u16 encr_types = WPS_ENCR_TYPES;
321	encr_types &= ~WPS_ENCR_WEP;
322#ifdef CONFIG_WPS_TESTING
323	if (wps_force_encr_types_in_use) {
324		wpa_printf(MSG_DEBUG,
325			   "WPS: Testing - replace encr type 0x%x with 0x%x",
326			   encr_types, wps_force_encr_types);
327		encr_types = wps_force_encr_types;
328	}
329#endif /* CONFIG_WPS_TESTING */
330	wpa_printf(MSG_DEBUG, "WPS:  * Encryption Type Flags (0x%x)",
331		   encr_types);
332	wpabuf_put_be16(msg, ATTR_ENCR_TYPE_FLAGS);
333	wpabuf_put_be16(msg, 2);
334	wpabuf_put_be16(msg, encr_types);
335	return 0;
336}
337
338
339int wps_build_conn_type_flags(struct wps_data *wps, struct wpabuf *msg)
340{
341	wpa_printf(MSG_DEBUG, "WPS:  * Connection Type Flags");
342	wpabuf_put_be16(msg, ATTR_CONN_TYPE_FLAGS);
343	wpabuf_put_be16(msg, 1);
344	wpabuf_put_u8(msg, WPS_CONN_ESS);
345	return 0;
346}
347
348
349int wps_build_assoc_state(struct wps_data *wps, struct wpabuf *msg)
350{
351	wpa_printf(MSG_DEBUG, "WPS:  * Association State");
352	wpabuf_put_be16(msg, ATTR_ASSOC_STATE);
353	wpabuf_put_be16(msg, 2);
354	wpabuf_put_be16(msg, WPS_ASSOC_NOT_ASSOC);
355	return 0;
356}
357
358
359int wps_build_key_wrap_auth(struct wps_data *wps, struct wpabuf *msg)
360{
361	u8 hash[SHA256_MAC_LEN];
362
363	wpa_printf(MSG_DEBUG, "WPS:  * Key Wrap Authenticator");
364	hmac_sha256(wps->authkey, WPS_AUTHKEY_LEN, wpabuf_head(msg),
365		    wpabuf_len(msg), hash);
366
367	wpabuf_put_be16(msg, ATTR_KEY_WRAP_AUTH);
368	wpabuf_put_be16(msg, WPS_KWA_LEN);
369	wpabuf_put_data(msg, hash, WPS_KWA_LEN);
370	return 0;
371}
372
373
374int wps_build_encr_settings(struct wps_data *wps, struct wpabuf *msg,
375			    struct wpabuf *plain)
376{
377	size_t pad_len;
378	const size_t block_size = 16;
379	u8 *iv, *data;
380
381	wpa_printf(MSG_DEBUG, "WPS:  * Encrypted Settings");
382
383	/* PKCS#5 v2.0 pad */
384	pad_len = block_size - wpabuf_len(plain) % block_size;
385	os_memset(wpabuf_put(plain, pad_len), pad_len, pad_len);
386
387	wpabuf_put_be16(msg, ATTR_ENCR_SETTINGS);
388	wpabuf_put_be16(msg, block_size + wpabuf_len(plain));
389
390	iv = wpabuf_put(msg, block_size);
391	if (random_get_bytes(iv, block_size) < 0)
392		return -1;
393
394	data = wpabuf_put(msg, 0);
395	wpabuf_put_buf(msg, plain);
396	if (aes_128_cbc_encrypt(wps->keywrapkey, iv, data, wpabuf_len(plain)))
397		return -1;
398
399	return 0;
400}
401
402
403#ifdef CONFIG_WPS_OOB
404int wps_build_oob_dev_pw(struct wpabuf *msg, u16 dev_pw_id,
405			 const struct wpabuf *pubkey, const u8 *dev_pw,
406			 size_t dev_pw_len)
407{
408	size_t hash_len;
409	const u8 *addr[1];
410	u8 pubkey_hash[WPS_HASH_LEN];
411
412	wpa_printf(MSG_DEBUG, "WPS:  * OOB Device Password (dev_pw_id=%u)",
413		   dev_pw_id);
414	addr[0] = wpabuf_head(pubkey);
415	hash_len = wpabuf_len(pubkey);
416	if (sha256_vector(1, addr, &hash_len, pubkey_hash) < 0)
417		return -1;
418#ifdef CONFIG_WPS_TESTING
419	if (wps_corrupt_pkhash) {
420		wpa_hexdump(MSG_DEBUG, "WPS: Real Public Key Hash",
421			    pubkey_hash, WPS_OOB_PUBKEY_HASH_LEN);
422		wpa_printf(MSG_INFO, "WPS: Testing - corrupt public key hash");
423		pubkey_hash[WPS_OOB_PUBKEY_HASH_LEN - 2]++;
424	}
425#endif /* CONFIG_WPS_TESTING */
426
427	wpabuf_put_be16(msg, ATTR_OOB_DEVICE_PASSWORD);
428	wpabuf_put_be16(msg, WPS_OOB_PUBKEY_HASH_LEN + 2 + dev_pw_len);
429	wpa_hexdump(MSG_DEBUG, "WPS: Public Key Hash",
430		    pubkey_hash, WPS_OOB_PUBKEY_HASH_LEN);
431	wpabuf_put_data(msg, pubkey_hash, WPS_OOB_PUBKEY_HASH_LEN);
432	wpabuf_put_be16(msg, dev_pw_id);
433	if (dev_pw) {
434		wpa_hexdump_key(MSG_DEBUG, "WPS: OOB Device Password",
435				dev_pw, dev_pw_len);
436		wpabuf_put_data(msg, dev_pw, dev_pw_len);
437	}
438
439	return 0;
440}
441#endif /* CONFIG_WPS_OOB */
442
443
444/* Encapsulate WPS IE data with one (or more, if needed) IE headers */
445struct wpabuf * wps_ie_encapsulate(struct wpabuf *data)
446{
447	struct wpabuf *ie;
448	const u8 *pos, *end;
449
450	ie = wpabuf_alloc(wpabuf_len(data) + 100);
451	if (ie == NULL) {
452		wpabuf_free(data);
453		return NULL;
454	}
455
456	pos = wpabuf_head(data);
457	end = pos + wpabuf_len(data);
458
459	while (end > pos) {
460		size_t frag_len = end - pos;
461		if (frag_len > 251)
462			frag_len = 251;
463		wpabuf_put_u8(ie, WLAN_EID_VENDOR_SPECIFIC);
464		wpabuf_put_u8(ie, 4 + frag_len);
465		wpabuf_put_be32(ie, WPS_DEV_OUI_WFA);
466		wpabuf_put_data(ie, pos, frag_len);
467		pos += frag_len;
468	}
469
470	wpabuf_free(data);
471
472	return ie;
473}
474
475
476int wps_build_mac_addr(struct wpabuf *msg, const u8 *addr)
477{
478	wpa_printf(MSG_DEBUG, "WPS:  * MAC Address (" MACSTR ")",
479		   MAC2STR(addr));
480	wpabuf_put_be16(msg, ATTR_MAC_ADDR);
481	wpabuf_put_be16(msg, ETH_ALEN);
482	wpabuf_put_data(msg, addr, ETH_ALEN);
483	return 0;
484}
485
486
487int wps_build_rf_bands_attr(struct wpabuf *msg, u8 rf_bands)
488{
489	wpa_printf(MSG_DEBUG, "WPS:  * RF Bands (%x)", rf_bands);
490	wpabuf_put_be16(msg, ATTR_RF_BANDS);
491	wpabuf_put_be16(msg, 1);
492	wpabuf_put_u8(msg, rf_bands);
493	return 0;
494}
495
496
497int wps_build_ap_channel(struct wpabuf *msg, u16 ap_channel)
498{
499	wpa_printf(MSG_DEBUG, "WPS:  * AP Channel (%u)", ap_channel);
500	wpabuf_put_be16(msg, ATTR_AP_CHANNEL);
501	wpabuf_put_be16(msg, 2);
502	wpabuf_put_be16(msg, ap_channel);
503	return 0;
504}
505