1/*
2 * Wi-Fi Protected Setup - attribute building
3 * Copyright (c) 2008, 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;
24
25	wpa_printf(MSG_DEBUG, "WPS:  * Public Key");
26	wpabuf_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 && wps->wps->ap &&
42		   wps->dev_pw_id == wps->wps->ap_nfc_dev_pw_id) {
43		wpa_printf(MSG_DEBUG, "WPS: Using NFC password token DH keys");
44		if (wps->wps->ap_nfc_dh_privkey == NULL) {
45			wpa_printf(MSG_DEBUG,
46				   "WPS: wps->wps->ap_nfc_dh_privkey == NULL");
47			return -1;
48		}
49		if (wps->wps->ap_nfc_dh_pubkey == NULL) {
50			wpa_printf(MSG_DEBUG,
51				   "WPS: wps->wps->ap_nfc_dh_pubkey == NULL");
52			return -1;
53		}
54		wps->dh_privkey = wpabuf_dup(wps->wps->ap_nfc_dh_privkey);
55		pubkey = wpabuf_dup(wps->wps->ap_nfc_dh_pubkey);
56		wps->dh_ctx = dh5_init_fixed(wps->dh_privkey, pubkey);
57#endif /* CONFIG_WPS_NFC */
58	} else {
59		wpa_printf(MSG_DEBUG, "WPS: Generate new DH keys");
60		dh5_free(wps->dh_ctx);
61		wps->dh_ctx = dh5_init(&wps->dh_privkey, &pubkey);
62		pubkey = wpabuf_zeropad(pubkey, 192);
63	}
64	if (wps->dh_ctx == NULL || wps->dh_privkey == NULL || pubkey == NULL) {
65		wpa_printf(MSG_DEBUG, "WPS: Failed to initialize "
66			   "Diffie-Hellman handshake");
67		wpabuf_free(pubkey);
68		return -1;
69	}
70	wpa_hexdump_buf_key(MSG_DEBUG, "WPS: DH Private Key", wps->dh_privkey);
71	wpa_hexdump_buf(MSG_DEBUG, "WPS: DH own Public Key", pubkey);
72
73	wpabuf_put_be16(msg, ATTR_PUBLIC_KEY);
74	wpabuf_put_be16(msg, wpabuf_len(pubkey));
75	wpabuf_put_buf(msg, pubkey);
76
77	if (wps->registrar) {
78		wpabuf_free(wps->dh_pubkey_r);
79		wps->dh_pubkey_r = pubkey;
80	} else {
81		wpabuf_free(wps->dh_pubkey_e);
82		wps->dh_pubkey_e = pubkey;
83	}
84
85	return 0;
86}
87
88
89int wps_build_req_type(struct wpabuf *msg, enum wps_request_type type)
90{
91	wpa_printf(MSG_DEBUG, "WPS:  * Request Type");
92	wpabuf_put_be16(msg, ATTR_REQUEST_TYPE);
93	wpabuf_put_be16(msg, 1);
94	wpabuf_put_u8(msg, type);
95	return 0;
96}
97
98
99int wps_build_resp_type(struct wpabuf *msg, enum wps_response_type type)
100{
101	wpa_printf(MSG_DEBUG, "WPS:  * Response Type (%d)", type);
102	wpabuf_put_be16(msg, ATTR_RESPONSE_TYPE);
103	wpabuf_put_be16(msg, 1);
104	wpabuf_put_u8(msg, type);
105	return 0;
106}
107
108
109int wps_build_config_methods(struct wpabuf *msg, u16 methods)
110{
111	wpa_printf(MSG_DEBUG, "WPS:  * Config Methods (%x)", methods);
112	wpabuf_put_be16(msg, ATTR_CONFIG_METHODS);
113	wpabuf_put_be16(msg, 2);
114	wpabuf_put_be16(msg, methods);
115	return 0;
116}
117
118
119int wps_build_uuid_e(struct wpabuf *msg, const u8 *uuid)
120{
121	wpa_printf(MSG_DEBUG, "WPS:  * UUID-E");
122	wpabuf_put_be16(msg, ATTR_UUID_E);
123	wpabuf_put_be16(msg, WPS_UUID_LEN);
124	wpabuf_put_data(msg, uuid, WPS_UUID_LEN);
125	return 0;
126}
127
128
129int wps_build_dev_password_id(struct wpabuf *msg, u16 id)
130{
131	wpa_printf(MSG_DEBUG, "WPS:  * Device Password ID (%d)", id);
132	wpabuf_put_be16(msg, ATTR_DEV_PASSWORD_ID);
133	wpabuf_put_be16(msg, 2);
134	wpabuf_put_be16(msg, id);
135	return 0;
136}
137
138
139int wps_build_config_error(struct wpabuf *msg, u16 err)
140{
141	wpa_printf(MSG_DEBUG, "WPS:  * Configuration Error (%d)", err);
142	wpabuf_put_be16(msg, ATTR_CONFIG_ERROR);
143	wpabuf_put_be16(msg, 2);
144	wpabuf_put_be16(msg, err);
145	return 0;
146}
147
148
149int wps_build_authenticator(struct wps_data *wps, struct wpabuf *msg)
150{
151	u8 hash[SHA256_MAC_LEN];
152	const u8 *addr[2];
153	size_t len[2];
154
155	if (wps->last_msg == NULL) {
156		wpa_printf(MSG_DEBUG, "WPS: Last message not available for "
157			   "building authenticator");
158		return -1;
159	}
160
161	/* Authenticator = HMAC-SHA256_AuthKey(M_prev || M_curr*)
162	 * (M_curr* is M_curr without the Authenticator attribute)
163	 */
164	addr[0] = wpabuf_head(wps->last_msg);
165	len[0] = wpabuf_len(wps->last_msg);
166	addr[1] = wpabuf_head(msg);
167	len[1] = wpabuf_len(msg);
168	hmac_sha256_vector(wps->authkey, WPS_AUTHKEY_LEN, 2, addr, len, hash);
169
170	wpa_printf(MSG_DEBUG, "WPS:  * Authenticator");
171	wpabuf_put_be16(msg, ATTR_AUTHENTICATOR);
172	wpabuf_put_be16(msg, WPS_AUTHENTICATOR_LEN);
173	wpabuf_put_data(msg, hash, WPS_AUTHENTICATOR_LEN);
174
175	return 0;
176}
177
178
179int wps_build_version(struct wpabuf *msg)
180{
181	/*
182	 * Note: This attribute is deprecated and set to hardcoded 0x10 for
183	 * backwards compatibility reasons. The real version negotiation is
184	 * done with Version2.
185	 */
186	wpa_printf(MSG_DEBUG, "WPS:  * Version (hardcoded 0x10)");
187	wpabuf_put_be16(msg, ATTR_VERSION);
188	wpabuf_put_be16(msg, 1);
189	wpabuf_put_u8(msg, 0x10);
190	return 0;
191}
192
193
194int wps_build_wfa_ext(struct wpabuf *msg, int req_to_enroll,
195		      const u8 *auth_macs, size_t auth_macs_count)
196{
197#ifdef CONFIG_WPS2
198	u8 *len;
199
200	wpabuf_put_be16(msg, ATTR_VENDOR_EXT);
201	len = wpabuf_put(msg, 2); /* to be filled */
202	wpabuf_put_be24(msg, WPS_VENDOR_ID_WFA);
203
204	wpa_printf(MSG_DEBUG, "WPS:  * Version2 (0x%x)", WPS_VERSION);
205	wpabuf_put_u8(msg, WFA_ELEM_VERSION2);
206	wpabuf_put_u8(msg, 1);
207	wpabuf_put_u8(msg, WPS_VERSION);
208
209	if (req_to_enroll) {
210		wpa_printf(MSG_DEBUG, "WPS:  * Request to Enroll (1)");
211		wpabuf_put_u8(msg, WFA_ELEM_REQUEST_TO_ENROLL);
212		wpabuf_put_u8(msg, 1);
213		wpabuf_put_u8(msg, 1);
214	}
215
216	if (auth_macs && auth_macs_count) {
217		size_t i;
218		wpa_printf(MSG_DEBUG, "WPS:  * AuthorizedMACs (count=%d)",
219			   (int) auth_macs_count);
220		wpabuf_put_u8(msg, WFA_ELEM_AUTHORIZEDMACS);
221		wpabuf_put_u8(msg, auth_macs_count * ETH_ALEN);
222		wpabuf_put_data(msg, auth_macs, auth_macs_count * ETH_ALEN);
223		for (i = 0; i < auth_macs_count; i++)
224			wpa_printf(MSG_DEBUG, "WPS:    AuthorizedMAC: " MACSTR,
225				   MAC2STR(&auth_macs[i * ETH_ALEN]));
226	}
227
228	WPA_PUT_BE16(len, (u8 *) wpabuf_put(msg, 0) - len - 2);
229#endif /* CONFIG_WPS2 */
230
231#ifdef CONFIG_WPS_TESTING
232	if (WPS_VERSION > 0x20) {
233		wpa_printf(MSG_DEBUG, "WPS:  * Extensibility Testing - extra "
234			   "attribute");
235		wpabuf_put_be16(msg, ATTR_EXTENSIBILITY_TEST);
236		wpabuf_put_be16(msg, 1);
237		wpabuf_put_u8(msg, 42);
238	}
239#endif /* CONFIG_WPS_TESTING */
240	return 0;
241}
242
243
244int wps_build_msg_type(struct wpabuf *msg, enum wps_msg_type msg_type)
245{
246	wpa_printf(MSG_DEBUG, "WPS:  * Message Type (%d)", msg_type);
247	wpabuf_put_be16(msg, ATTR_MSG_TYPE);
248	wpabuf_put_be16(msg, 1);
249	wpabuf_put_u8(msg, msg_type);
250	return 0;
251}
252
253
254int wps_build_enrollee_nonce(struct wps_data *wps, struct wpabuf *msg)
255{
256	wpa_printf(MSG_DEBUG, "WPS:  * Enrollee Nonce");
257	wpabuf_put_be16(msg, ATTR_ENROLLEE_NONCE);
258	wpabuf_put_be16(msg, WPS_NONCE_LEN);
259	wpabuf_put_data(msg, wps->nonce_e, WPS_NONCE_LEN);
260	return 0;
261}
262
263
264int wps_build_registrar_nonce(struct wps_data *wps, struct wpabuf *msg)
265{
266	wpa_printf(MSG_DEBUG, "WPS:  * Registrar Nonce");
267	wpabuf_put_be16(msg, ATTR_REGISTRAR_NONCE);
268	wpabuf_put_be16(msg, WPS_NONCE_LEN);
269	wpabuf_put_data(msg, wps->nonce_r, WPS_NONCE_LEN);
270	return 0;
271}
272
273
274int wps_build_auth_type_flags(struct wps_data *wps, struct wpabuf *msg)
275{
276	u16 auth_types = WPS_AUTH_TYPES;
277#ifdef CONFIG_WPS2
278	auth_types &= ~WPS_AUTH_SHARED;
279#endif /* CONFIG_WPS2 */
280	wpa_printf(MSG_DEBUG, "WPS:  * Authentication Type Flags");
281	wpabuf_put_be16(msg, ATTR_AUTH_TYPE_FLAGS);
282	wpabuf_put_be16(msg, 2);
283	wpabuf_put_be16(msg, auth_types);
284	return 0;
285}
286
287
288int wps_build_encr_type_flags(struct wps_data *wps, struct wpabuf *msg)
289{
290	u16 encr_types = WPS_ENCR_TYPES;
291#ifdef CONFIG_WPS2
292	encr_types &= ~WPS_ENCR_WEP;
293#endif /* CONFIG_WPS2 */
294	wpa_printf(MSG_DEBUG, "WPS:  * Encryption Type Flags");
295	wpabuf_put_be16(msg, ATTR_ENCR_TYPE_FLAGS);
296	wpabuf_put_be16(msg, 2);
297	wpabuf_put_be16(msg, encr_types);
298	return 0;
299}
300
301
302int wps_build_conn_type_flags(struct wps_data *wps, struct wpabuf *msg)
303{
304	wpa_printf(MSG_DEBUG, "WPS:  * Connection Type Flags");
305	wpabuf_put_be16(msg, ATTR_CONN_TYPE_FLAGS);
306	wpabuf_put_be16(msg, 1);
307	wpabuf_put_u8(msg, WPS_CONN_ESS);
308	return 0;
309}
310
311
312int wps_build_assoc_state(struct wps_data *wps, struct wpabuf *msg)
313{
314	wpa_printf(MSG_DEBUG, "WPS:  * Association State");
315	wpabuf_put_be16(msg, ATTR_ASSOC_STATE);
316	wpabuf_put_be16(msg, 2);
317	wpabuf_put_be16(msg, WPS_ASSOC_NOT_ASSOC);
318	return 0;
319}
320
321
322int wps_build_key_wrap_auth(struct wps_data *wps, struct wpabuf *msg)
323{
324	u8 hash[SHA256_MAC_LEN];
325
326	wpa_printf(MSG_DEBUG, "WPS:  * Key Wrap Authenticator");
327	hmac_sha256(wps->authkey, WPS_AUTHKEY_LEN, wpabuf_head(msg),
328		    wpabuf_len(msg), hash);
329
330	wpabuf_put_be16(msg, ATTR_KEY_WRAP_AUTH);
331	wpabuf_put_be16(msg, WPS_KWA_LEN);
332	wpabuf_put_data(msg, hash, WPS_KWA_LEN);
333	return 0;
334}
335
336
337int wps_build_encr_settings(struct wps_data *wps, struct wpabuf *msg,
338			    struct wpabuf *plain)
339{
340	size_t pad_len;
341	const size_t block_size = 16;
342	u8 *iv, *data;
343
344	wpa_printf(MSG_DEBUG, "WPS:  * Encrypted Settings");
345
346	/* PKCS#5 v2.0 pad */
347	pad_len = block_size - wpabuf_len(plain) % block_size;
348	os_memset(wpabuf_put(plain, pad_len), pad_len, pad_len);
349
350	wpabuf_put_be16(msg, ATTR_ENCR_SETTINGS);
351	wpabuf_put_be16(msg, block_size + wpabuf_len(plain));
352
353	iv = wpabuf_put(msg, block_size);
354	if (random_get_bytes(iv, block_size) < 0)
355		return -1;
356
357	data = wpabuf_put(msg, 0);
358	wpabuf_put_buf(msg, plain);
359	if (aes_128_cbc_encrypt(wps->keywrapkey, iv, data, wpabuf_len(plain)))
360		return -1;
361
362	return 0;
363}
364
365
366#ifdef CONFIG_WPS_OOB
367int wps_build_oob_dev_pw(struct wpabuf *msg, u16 dev_pw_id,
368			 const struct wpabuf *pubkey, const u8 *dev_pw,
369			 size_t dev_pw_len)
370{
371	size_t hash_len;
372	const u8 *addr[1];
373	u8 pubkey_hash[WPS_HASH_LEN];
374
375	addr[0] = wpabuf_head(pubkey);
376	hash_len = wpabuf_len(pubkey);
377	sha256_vector(1, addr, &hash_len, pubkey_hash);
378
379	wpabuf_put_be16(msg, ATTR_OOB_DEVICE_PASSWORD);
380	wpabuf_put_be16(msg, WPS_OOB_PUBKEY_HASH_LEN + 2 + dev_pw_len);
381	wpabuf_put_data(msg, pubkey_hash, WPS_OOB_PUBKEY_HASH_LEN);
382	wpabuf_put_be16(msg, dev_pw_id);
383	wpabuf_put_data(msg, dev_pw, dev_pw_len);
384
385	return 0;
386}
387#endif /* CONFIG_WPS_OOB */
388
389
390/* Encapsulate WPS IE data with one (or more, if needed) IE headers */
391struct wpabuf * wps_ie_encapsulate(struct wpabuf *data)
392{
393	struct wpabuf *ie;
394	const u8 *pos, *end;
395
396	ie = wpabuf_alloc(wpabuf_len(data) + 100);
397	if (ie == NULL) {
398		wpabuf_free(data);
399		return NULL;
400	}
401
402	pos = wpabuf_head(data);
403	end = pos + wpabuf_len(data);
404
405	while (end > pos) {
406		size_t frag_len = end - pos;
407		if (frag_len > 251)
408			frag_len = 251;
409		wpabuf_put_u8(ie, WLAN_EID_VENDOR_SPECIFIC);
410		wpabuf_put_u8(ie, 4 + frag_len);
411		wpabuf_put_be32(ie, WPS_DEV_OUI_WFA);
412		wpabuf_put_data(ie, pos, frag_len);
413		pos += frag_len;
414	}
415
416	wpabuf_free(data);
417
418	return ie;
419}
420
421
422int wps_build_mac_addr(struct wpabuf *msg, const u8 *addr)
423{
424	wpa_printf(MSG_DEBUG, "WPS:  * MAC Address (" MACSTR ")",
425		   MAC2STR(addr));
426	wpabuf_put_be16(msg, ATTR_MAC_ADDR);
427	wpabuf_put_be16(msg, ETH_ALEN);
428	wpabuf_put_data(msg, addr, ETH_ALEN);
429	return 0;
430}
431