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      1 /*
      2  * Wi-Fi Protected Setup - common functionality
      3  * Copyright (c) 2008-2012, 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 "common/defs.h"
     13 #include "common/ieee802_11_common.h"
     14 #include "crypto/aes_wrap.h"
     15 #include "crypto/crypto.h"
     16 #include "crypto/dh_group5.h"
     17 #include "crypto/sha1.h"
     18 #include "crypto/sha256.h"
     19 #include "crypto/random.h"
     20 #include "wps_i.h"
     21 #include "wps_dev_attr.h"
     22 
     23 
     24 void wps_kdf(const u8 *key, const u8 *label_prefix, size_t label_prefix_len,
     25 	     const char *label, u8 *res, size_t res_len)
     26 {
     27 	u8 i_buf[4], key_bits[4];
     28 	const u8 *addr[4];
     29 	size_t len[4];
     30 	int i, iter;
     31 	u8 hash[SHA256_MAC_LEN], *opos;
     32 	size_t left;
     33 
     34 	WPA_PUT_BE32(key_bits, res_len * 8);
     35 
     36 	addr[0] = i_buf;
     37 	len[0] = sizeof(i_buf);
     38 	addr[1] = label_prefix;
     39 	len[1] = label_prefix_len;
     40 	addr[2] = (const u8 *) label;
     41 	len[2] = os_strlen(label);
     42 	addr[3] = key_bits;
     43 	len[3] = sizeof(key_bits);
     44 
     45 	iter = (res_len + SHA256_MAC_LEN - 1) / SHA256_MAC_LEN;
     46 	opos = res;
     47 	left = res_len;
     48 
     49 	for (i = 1; i <= iter; i++) {
     50 		WPA_PUT_BE32(i_buf, i);
     51 		hmac_sha256_vector(key, SHA256_MAC_LEN, 4, addr, len, hash);
     52 		if (i < iter) {
     53 			os_memcpy(opos, hash, SHA256_MAC_LEN);
     54 			opos += SHA256_MAC_LEN;
     55 			left -= SHA256_MAC_LEN;
     56 		} else
     57 			os_memcpy(opos, hash, left);
     58 	}
     59 }
     60 
     61 
     62 int wps_derive_keys(struct wps_data *wps)
     63 {
     64 	struct wpabuf *pubkey, *dh_shared;
     65 	u8 dhkey[SHA256_MAC_LEN], kdk[SHA256_MAC_LEN];
     66 	const u8 *addr[3];
     67 	size_t len[3];
     68 	u8 keys[WPS_AUTHKEY_LEN + WPS_KEYWRAPKEY_LEN + WPS_EMSK_LEN];
     69 
     70 	if (wps->dh_privkey == NULL) {
     71 		wpa_printf(MSG_DEBUG, "WPS: Own DH private key not available");
     72 		return -1;
     73 	}
     74 
     75 	pubkey = wps->registrar ? wps->dh_pubkey_e : wps->dh_pubkey_r;
     76 	if (pubkey == NULL) {
     77 		wpa_printf(MSG_DEBUG, "WPS: Peer DH public key not available");
     78 		return -1;
     79 	}
     80 
     81 	wpa_hexdump_buf_key(MSG_DEBUG, "WPS: DH Private Key", wps->dh_privkey);
     82 	wpa_hexdump_buf(MSG_DEBUG, "WPS: DH peer Public Key", pubkey);
     83 	dh_shared = dh5_derive_shared(wps->dh_ctx, pubkey, wps->dh_privkey);
     84 	dh5_free(wps->dh_ctx);
     85 	wps->dh_ctx = NULL;
     86 	dh_shared = wpabuf_zeropad(dh_shared, 192);
     87 	if (dh_shared == NULL) {
     88 		wpa_printf(MSG_DEBUG, "WPS: Failed to derive DH shared key");
     89 		return -1;
     90 	}
     91 
     92 	/* Own DH private key is not needed anymore */
     93 	wpabuf_free(wps->dh_privkey);
     94 	wps->dh_privkey = NULL;
     95 
     96 	wpa_hexdump_buf_key(MSG_DEBUG, "WPS: DH shared key", dh_shared);
     97 
     98 	/* DHKey = SHA-256(g^AB mod p) */
     99 	addr[0] = wpabuf_head(dh_shared);
    100 	len[0] = wpabuf_len(dh_shared);
    101 	sha256_vector(1, addr, len, dhkey);
    102 	wpa_hexdump_key(MSG_DEBUG, "WPS: DHKey", dhkey, sizeof(dhkey));
    103 	wpabuf_free(dh_shared);
    104 
    105 	/* KDK = HMAC-SHA-256_DHKey(N1 || EnrolleeMAC || N2) */
    106 	addr[0] = wps->nonce_e;
    107 	len[0] = WPS_NONCE_LEN;
    108 	addr[1] = wps->mac_addr_e;
    109 	len[1] = ETH_ALEN;
    110 	addr[2] = wps->nonce_r;
    111 	len[2] = WPS_NONCE_LEN;
    112 	hmac_sha256_vector(dhkey, sizeof(dhkey), 3, addr, len, kdk);
    113 	wpa_hexdump_key(MSG_DEBUG, "WPS: KDK", kdk, sizeof(kdk));
    114 
    115 	wps_kdf(kdk, NULL, 0, "Wi-Fi Easy and Secure Key Derivation",
    116 		keys, sizeof(keys));
    117 	os_memcpy(wps->authkey, keys, WPS_AUTHKEY_LEN);
    118 	os_memcpy(wps->keywrapkey, keys + WPS_AUTHKEY_LEN, WPS_KEYWRAPKEY_LEN);
    119 	os_memcpy(wps->emsk, keys + WPS_AUTHKEY_LEN + WPS_KEYWRAPKEY_LEN,
    120 		  WPS_EMSK_LEN);
    121 
    122 	wpa_hexdump_key(MSG_DEBUG, "WPS: AuthKey",
    123 			wps->authkey, WPS_AUTHKEY_LEN);
    124 	wpa_hexdump_key(MSG_DEBUG, "WPS: KeyWrapKey",
    125 			wps->keywrapkey, WPS_KEYWRAPKEY_LEN);
    126 	wpa_hexdump_key(MSG_DEBUG, "WPS: EMSK", wps->emsk, WPS_EMSK_LEN);
    127 
    128 	return 0;
    129 }
    130 
    131 
    132 void wps_derive_psk(struct wps_data *wps, const u8 *dev_passwd,
    133 		    size_t dev_passwd_len)
    134 {
    135 	u8 hash[SHA256_MAC_LEN];
    136 
    137 	hmac_sha256(wps->authkey, WPS_AUTHKEY_LEN, dev_passwd,
    138 		    (dev_passwd_len + 1) / 2, hash);
    139 	os_memcpy(wps->psk1, hash, WPS_PSK_LEN);
    140 	hmac_sha256(wps->authkey, WPS_AUTHKEY_LEN,
    141 		    dev_passwd + (dev_passwd_len + 1) / 2,
    142 		    dev_passwd_len / 2, hash);
    143 	os_memcpy(wps->psk2, hash, WPS_PSK_LEN);
    144 
    145 	wpa_hexdump_ascii_key(MSG_DEBUG, "WPS: Device Password",
    146 			      dev_passwd, dev_passwd_len);
    147 	wpa_hexdump_key(MSG_DEBUG, "WPS: PSK1", wps->psk1, WPS_PSK_LEN);
    148 	wpa_hexdump_key(MSG_DEBUG, "WPS: PSK2", wps->psk2, WPS_PSK_LEN);
    149 }
    150 
    151 
    152 struct wpabuf * wps_decrypt_encr_settings(struct wps_data *wps, const u8 *encr,
    153 					  size_t encr_len)
    154 {
    155 	struct wpabuf *decrypted;
    156 	const size_t block_size = 16;
    157 	size_t i;
    158 	u8 pad;
    159 	const u8 *pos;
    160 
    161 	/* AES-128-CBC */
    162 	if (encr == NULL || encr_len < 2 * block_size || encr_len % block_size)
    163 	{
    164 		wpa_printf(MSG_DEBUG, "WPS: No Encrypted Settings received");
    165 		return NULL;
    166 	}
    167 
    168 	decrypted = wpabuf_alloc(encr_len - block_size);
    169 	if (decrypted == NULL)
    170 		return NULL;
    171 
    172 	wpa_hexdump(MSG_MSGDUMP, "WPS: Encrypted Settings", encr, encr_len);
    173 	wpabuf_put_data(decrypted, encr + block_size, encr_len - block_size);
    174 	if (aes_128_cbc_decrypt(wps->keywrapkey, encr, wpabuf_mhead(decrypted),
    175 				wpabuf_len(decrypted))) {
    176 		wpabuf_free(decrypted);
    177 		return NULL;
    178 	}
    179 
    180 	wpa_hexdump_buf_key(MSG_MSGDUMP, "WPS: Decrypted Encrypted Settings",
    181 			    decrypted);
    182 
    183 	pos = wpabuf_head_u8(decrypted) + wpabuf_len(decrypted) - 1;
    184 	pad = *pos;
    185 	if (pad > wpabuf_len(decrypted)) {
    186 		wpa_printf(MSG_DEBUG, "WPS: Invalid PKCS#5 v2.0 pad value");
    187 		wpabuf_free(decrypted);
    188 		return NULL;
    189 	}
    190 	for (i = 0; i < pad; i++) {
    191 		if (*pos-- != pad) {
    192 			wpa_printf(MSG_DEBUG, "WPS: Invalid PKCS#5 v2.0 pad "
    193 				   "string");
    194 			wpabuf_free(decrypted);
    195 			return NULL;
    196 		}
    197 	}
    198 	decrypted->used -= pad;
    199 
    200 	return decrypted;
    201 }
    202 
    203 
    204 /**
    205  * wps_pin_checksum - Compute PIN checksum
    206  * @pin: Seven digit PIN (i.e., eight digit PIN without the checksum digit)
    207  * Returns: Checksum digit
    208  */
    209 unsigned int wps_pin_checksum(unsigned int pin)
    210 {
    211 	unsigned int accum = 0;
    212 	while (pin) {
    213 		accum += 3 * (pin % 10);
    214 		pin /= 10;
    215 		accum += pin % 10;
    216 		pin /= 10;
    217 	}
    218 
    219 	return (10 - accum % 10) % 10;
    220 }
    221 
    222 
    223 /**
    224  * wps_pin_valid - Check whether a PIN has a valid checksum
    225  * @pin: Eight digit PIN (i.e., including the checksum digit)
    226  * Returns: 1 if checksum digit is valid, or 0 if not
    227  */
    228 unsigned int wps_pin_valid(unsigned int pin)
    229 {
    230 	return wps_pin_checksum(pin / 10) == (pin % 10);
    231 }
    232 
    233 
    234 /**
    235  * wps_generate_pin - Generate a random PIN
    236  * Returns: Eight digit PIN (i.e., including the checksum digit)
    237  */
    238 int wps_generate_pin(unsigned int *pin)
    239 {
    240 	unsigned int val;
    241 
    242 	/* Generate seven random digits for the PIN */
    243 	if (random_get_bytes((unsigned char *) &val, sizeof(val)) < 0)
    244 		return -1;
    245 	val %= 10000000;
    246 
    247 	/* Append checksum digit */
    248 	*pin = val * 10 + wps_pin_checksum(val);
    249 	return 0;
    250 }
    251 
    252 
    253 int wps_pin_str_valid(const char *pin)
    254 {
    255 	const char *p;
    256 	size_t len;
    257 
    258 	p = pin;
    259 	while (*p >= '0' && *p <= '9')
    260 		p++;
    261 	if (*p != '\0')
    262 		return 0;
    263 
    264 	len = p - pin;
    265 	return len == 4 || len == 8;
    266 }
    267 
    268 
    269 void wps_fail_event(struct wps_context *wps, enum wps_msg_type msg,
    270 		    u16 config_error, u16 error_indication, const u8 *mac_addr)
    271 {
    272 	union wps_event_data data;
    273 
    274 	if (wps->event_cb == NULL)
    275 		return;
    276 
    277 	os_memset(&data, 0, sizeof(data));
    278 	data.fail.msg = msg;
    279 	data.fail.config_error = config_error;
    280 	data.fail.error_indication = error_indication;
    281 	os_memcpy(data.fail.peer_macaddr, mac_addr, ETH_ALEN);
    282 	wps->event_cb(wps->cb_ctx, WPS_EV_FAIL, &data);
    283 }
    284 
    285 
    286 void wps_success_event(struct wps_context *wps, const u8 *mac_addr)
    287 {
    288 	union wps_event_data data;
    289 
    290 	if (wps->event_cb == NULL)
    291 		return;
    292 
    293 	os_memset(&data, 0, sizeof(data));
    294 	os_memcpy(data.success.peer_macaddr, mac_addr, ETH_ALEN);
    295 	wps->event_cb(wps->cb_ctx, WPS_EV_SUCCESS, &data);
    296 }
    297 
    298 
    299 void wps_pwd_auth_fail_event(struct wps_context *wps, int enrollee, int part,
    300 			     const u8 *mac_addr)
    301 {
    302 	union wps_event_data data;
    303 
    304 	if (wps->event_cb == NULL)
    305 		return;
    306 
    307 	os_memset(&data, 0, sizeof(data));
    308 	data.pwd_auth_fail.enrollee = enrollee;
    309 	data.pwd_auth_fail.part = part;
    310 	os_memcpy(data.pwd_auth_fail.peer_macaddr, mac_addr, ETH_ALEN);
    311 	wps->event_cb(wps->cb_ctx, WPS_EV_PWD_AUTH_FAIL, &data);
    312 }
    313 
    314 
    315 void wps_pbc_overlap_event(struct wps_context *wps)
    316 {
    317 	if (wps->event_cb == NULL)
    318 		return;
    319 
    320 	wps->event_cb(wps->cb_ctx, WPS_EV_PBC_OVERLAP, NULL);
    321 }
    322 
    323 
    324 void wps_pbc_timeout_event(struct wps_context *wps)
    325 {
    326 	if (wps->event_cb == NULL)
    327 		return;
    328 
    329 	wps->event_cb(wps->cb_ctx, WPS_EV_PBC_TIMEOUT, NULL);
    330 }
    331 
    332 
    333 void wps_pbc_active_event(struct wps_context *wps)
    334 {
    335 	if (wps->event_cb == NULL)
    336 		return;
    337 
    338 	wps->event_cb(wps->cb_ctx, WPS_EV_PBC_ACTIVE, NULL);
    339 }
    340 
    341 
    342 void wps_pbc_disable_event(struct wps_context *wps)
    343 {
    344 	if (wps->event_cb == NULL)
    345 		return;
    346 
    347 	wps->event_cb(wps->cb_ctx, WPS_EV_PBC_DISABLE, NULL);
    348 }
    349 
    350 
    351 #ifdef CONFIG_WPS_OOB
    352 
    353 struct wpabuf * wps_get_oob_cred(struct wps_context *wps, int rf_band,
    354 				 int channel)
    355 {
    356 	struct wps_data data;
    357 	struct wpabuf *plain;
    358 
    359 	plain = wpabuf_alloc(500);
    360 	if (plain == NULL) {
    361 		wpa_printf(MSG_ERROR, "WPS: Failed to allocate memory for OOB "
    362 			   "credential");
    363 		return NULL;
    364 	}
    365 
    366 	os_memset(&data, 0, sizeof(data));
    367 	data.wps = wps;
    368 	data.auth_type = wps->auth_types;
    369 	data.encr_type = wps->encr_types;
    370 	if (wps_build_cred(&data, plain) ||
    371 	    (rf_band && wps_build_rf_bands_attr(plain, rf_band)) ||
    372 	    (channel && wps_build_ap_channel(plain, channel)) ||
    373 	    wps_build_mac_addr(plain, wps->dev.mac_addr) ||
    374 	    wps_build_wfa_ext(plain, 0, NULL, 0)) {
    375 		os_free(data.new_psk);
    376 		wpabuf_free(plain);
    377 		return NULL;
    378 	}
    379 
    380 	if (wps->wps_state == WPS_STATE_NOT_CONFIGURED && data.new_psk &&
    381 	    wps->ap) {
    382 		struct wps_credential cred;
    383 
    384 		wpa_printf(MSG_DEBUG, "WPS: Moving to Configured state based "
    385 			   "on credential token generation");
    386 
    387 		os_memset(&cred, 0, sizeof(cred));
    388 		os_memcpy(cred.ssid, wps->ssid, wps->ssid_len);
    389 		cred.ssid_len = wps->ssid_len;
    390 		cred.auth_type = WPS_AUTH_WPAPSK | WPS_AUTH_WPA2PSK;
    391 		cred.encr_type = WPS_ENCR_TKIP | WPS_ENCR_AES;
    392 		os_memcpy(cred.key, data.new_psk, data.new_psk_len);
    393 		cred.key_len = data.new_psk_len;
    394 
    395 		wps->wps_state = WPS_STATE_CONFIGURED;
    396 		wpa_hexdump_ascii_key(MSG_DEBUG,
    397 				      "WPS: Generated random passphrase",
    398 				      data.new_psk, data.new_psk_len);
    399 		if (wps->cred_cb)
    400 			wps->cred_cb(wps->cb_ctx, &cred);
    401 	}
    402 
    403 	os_free(data.new_psk);
    404 
    405 	return plain;
    406 }
    407 
    408 
    409 struct wpabuf * wps_build_nfc_pw_token(u16 dev_pw_id,
    410 				       const struct wpabuf *pubkey,
    411 				       const struct wpabuf *dev_pw)
    412 {
    413 	struct wpabuf *data;
    414 
    415 	data = wpabuf_alloc(200);
    416 	if (data == NULL)
    417 		return NULL;
    418 
    419 	if (wps_build_oob_dev_pw(data, dev_pw_id, pubkey,
    420 				 wpabuf_head(dev_pw), wpabuf_len(dev_pw)) ||
    421 	    wps_build_wfa_ext(data, 0, NULL, 0)) {
    422 		wpa_printf(MSG_ERROR, "WPS: Failed to build NFC password "
    423 			   "token");
    424 		wpabuf_free(data);
    425 		return NULL;
    426 	}
    427 
    428 	return data;
    429 }
    430 
    431 
    432 int wps_oob_use_cred(struct wps_context *wps, struct wps_parse_attr *attr)
    433 {
    434 	struct wpabuf msg;
    435 	size_t i;
    436 
    437 	for (i = 0; i < attr->num_cred; i++) {
    438 		struct wps_credential local_cred;
    439 		struct wps_parse_attr cattr;
    440 
    441 		os_memset(&local_cred, 0, sizeof(local_cred));
    442 		wpabuf_set(&msg, attr->cred[i], attr->cred_len[i]);
    443 		if (wps_parse_msg(&msg, &cattr) < 0 ||
    444 		    wps_process_cred(&cattr, &local_cred)) {
    445 			wpa_printf(MSG_ERROR, "WPS: Failed to parse OOB "
    446 				   "credential");
    447 			return -1;
    448 		}
    449 		wps->cred_cb(wps->cb_ctx, &local_cred);
    450 	}
    451 
    452 	return 0;
    453 }
    454 
    455 
    456 #endif /* CONFIG_WPS_OOB */
    457 
    458 
    459 int wps_dev_type_str2bin(const char *str, u8 dev_type[WPS_DEV_TYPE_LEN])
    460 {
    461 	const char *pos;
    462 
    463 	/* <categ>-<OUI>-<subcateg> */
    464 	WPA_PUT_BE16(dev_type, atoi(str));
    465 	pos = os_strchr(str, '-');
    466 	if (pos == NULL)
    467 		return -1;
    468 	pos++;
    469 	if (hexstr2bin(pos, &dev_type[2], 4))
    470 		return -1;
    471 	pos = os_strchr(pos, '-');
    472 	if (pos == NULL)
    473 		return -1;
    474 	pos++;
    475 	WPA_PUT_BE16(&dev_type[6], atoi(pos));
    476 
    477 
    478 	return 0;
    479 }
    480 
    481 
    482 char * wps_dev_type_bin2str(const u8 dev_type[WPS_DEV_TYPE_LEN], char *buf,
    483 			    size_t buf_len)
    484 {
    485 	int ret;
    486 
    487 	ret = os_snprintf(buf, buf_len, "%u-%08X-%u",
    488 			  WPA_GET_BE16(dev_type), WPA_GET_BE32(&dev_type[2]),
    489 			  WPA_GET_BE16(&dev_type[6]));
    490 	if (os_snprintf_error(buf_len, ret))
    491 		return NULL;
    492 
    493 	return buf;
    494 }
    495 
    496 
    497 void uuid_gen_mac_addr(const u8 *mac_addr, u8 *uuid)
    498 {
    499 	const u8 *addr[2];
    500 	size_t len[2];
    501 	u8 hash[SHA1_MAC_LEN];
    502 	u8 nsid[16] = {
    503 		0x52, 0x64, 0x80, 0xf8,
    504 		0xc9, 0x9b,
    505 		0x4b, 0xe5,
    506 		0xa6, 0x55,
    507 		0x58, 0xed, 0x5f, 0x5d, 0x60, 0x84
    508 	};
    509 
    510 	addr[0] = nsid;
    511 	len[0] = sizeof(nsid);
    512 	addr[1] = mac_addr;
    513 	len[1] = 6;
    514 	sha1_vector(2, addr, len, hash);
    515 	os_memcpy(uuid, hash, 16);
    516 
    517 	/* Version: 5 = named-based version using SHA-1 */
    518 	uuid[6] = (5 << 4) | (uuid[6] & 0x0f);
    519 
    520 	/* Variant specified in RFC 4122 */
    521 	uuid[8] = 0x80 | (uuid[8] & 0x3f);
    522 }
    523 
    524 
    525 u16 wps_config_methods_str2bin(const char *str)
    526 {
    527 	u16 methods = 0;
    528 
    529 	if (str == NULL || str[0] == '\0') {
    530 		/* Default to enabling methods based on build configuration */
    531 		methods |= WPS_CONFIG_DISPLAY | WPS_CONFIG_KEYPAD;
    532 		methods |= WPS_CONFIG_VIRT_DISPLAY;
    533 #ifdef CONFIG_WPS_NFC
    534 		methods |= WPS_CONFIG_NFC_INTERFACE;
    535 #endif /* CONFIG_WPS_NFC */
    536 #ifdef CONFIG_P2P
    537 		methods |= WPS_CONFIG_P2PS;
    538 #endif /* CONFIG_P2P */
    539 	} else {
    540 		if (os_strstr(str, "ethernet"))
    541 			methods |= WPS_CONFIG_ETHERNET;
    542 		if (os_strstr(str, "label"))
    543 			methods |= WPS_CONFIG_LABEL;
    544 		if (os_strstr(str, "display"))
    545 			methods |= WPS_CONFIG_DISPLAY;
    546 		if (os_strstr(str, "ext_nfc_token"))
    547 			methods |= WPS_CONFIG_EXT_NFC_TOKEN;
    548 		if (os_strstr(str, "int_nfc_token"))
    549 			methods |= WPS_CONFIG_INT_NFC_TOKEN;
    550 		if (os_strstr(str, "nfc_interface"))
    551 			methods |= WPS_CONFIG_NFC_INTERFACE;
    552 		if (os_strstr(str, "push_button"))
    553 			methods |= WPS_CONFIG_PUSHBUTTON;
    554 		if (os_strstr(str, "keypad"))
    555 			methods |= WPS_CONFIG_KEYPAD;
    556 		if (os_strstr(str, "virtual_display"))
    557 			methods |= WPS_CONFIG_VIRT_DISPLAY;
    558 		if (os_strstr(str, "physical_display"))
    559 			methods |= WPS_CONFIG_PHY_DISPLAY;
    560 		if (os_strstr(str, "virtual_push_button"))
    561 			methods |= WPS_CONFIG_VIRT_PUSHBUTTON;
    562 		if (os_strstr(str, "physical_push_button"))
    563 			methods |= WPS_CONFIG_PHY_PUSHBUTTON;
    564 		if (os_strstr(str, "p2ps"))
    565 			methods |= WPS_CONFIG_P2PS;
    566 	}
    567 
    568 	return methods;
    569 }
    570 
    571 
    572 struct wpabuf * wps_build_wsc_ack(struct wps_data *wps)
    573 {
    574 	struct wpabuf *msg;
    575 
    576 	wpa_printf(MSG_DEBUG, "WPS: Building Message WSC_ACK");
    577 
    578 	msg = wpabuf_alloc(1000);
    579 	if (msg == NULL)
    580 		return NULL;
    581 
    582 	if (wps_build_version(msg) ||
    583 	    wps_build_msg_type(msg, WPS_WSC_ACK) ||
    584 	    wps_build_enrollee_nonce(wps, msg) ||
    585 	    wps_build_registrar_nonce(wps, msg) ||
    586 	    wps_build_wfa_ext(msg, 0, NULL, 0)) {
    587 		wpabuf_free(msg);
    588 		return NULL;
    589 	}
    590 
    591 	return msg;
    592 }
    593 
    594 
    595 struct wpabuf * wps_build_wsc_nack(struct wps_data *wps)
    596 {
    597 	struct wpabuf *msg;
    598 
    599 	wpa_printf(MSG_DEBUG, "WPS: Building Message WSC_NACK");
    600 
    601 	msg = wpabuf_alloc(1000);
    602 	if (msg == NULL)
    603 		return NULL;
    604 
    605 	if (wps_build_version(msg) ||
    606 	    wps_build_msg_type(msg, WPS_WSC_NACK) ||
    607 	    wps_build_enrollee_nonce(wps, msg) ||
    608 	    wps_build_registrar_nonce(wps, msg) ||
    609 	    wps_build_config_error(msg, wps->config_error) ||
    610 	    wps_build_wfa_ext(msg, 0, NULL, 0)) {
    611 		wpabuf_free(msg);
    612 		return NULL;
    613 	}
    614 
    615 	return msg;
    616 }
    617 
    618 
    619 #ifdef CONFIG_WPS_NFC
    620 
    621 struct wpabuf * wps_nfc_token_build(int ndef, int id, struct wpabuf *pubkey,
    622 				    struct wpabuf *dev_pw)
    623 {
    624 	struct wpabuf *ret;
    625 
    626 	if (pubkey == NULL || dev_pw == NULL)
    627 		return NULL;
    628 
    629 	ret = wps_build_nfc_pw_token(id, pubkey, dev_pw);
    630 	if (ndef && ret) {
    631 		struct wpabuf *tmp;
    632 		tmp = ndef_build_wifi(ret);
    633 		wpabuf_free(ret);
    634 		if (tmp == NULL)
    635 			return NULL;
    636 		ret = tmp;
    637 	}
    638 
    639 	return ret;
    640 }
    641 
    642 
    643 int wps_nfc_gen_dh(struct wpabuf **pubkey, struct wpabuf **privkey)
    644 {
    645 	struct wpabuf *priv = NULL, *pub = NULL;
    646 	void *dh_ctx;
    647 
    648 	dh_ctx = dh5_init(&priv, &pub);
    649 	if (dh_ctx == NULL)
    650 		return -1;
    651 	pub = wpabuf_zeropad(pub, 192);
    652 	if (pub == NULL) {
    653 		wpabuf_free(priv);
    654 		return -1;
    655 	}
    656 	wpa_hexdump_buf(MSG_DEBUG, "WPS: Generated new DH pubkey", pub);
    657 	dh5_free(dh_ctx);
    658 
    659 	wpabuf_free(*pubkey);
    660 	*pubkey = pub;
    661 	wpabuf_free(*privkey);
    662 	*privkey = priv;
    663 
    664 	return 0;
    665 }
    666 
    667 
    668 struct wpabuf * wps_nfc_token_gen(int ndef, int *id, struct wpabuf **pubkey,
    669 				  struct wpabuf **privkey,
    670 				  struct wpabuf **dev_pw)
    671 {
    672 	struct wpabuf *pw;
    673 	u16 val;
    674 
    675 	pw = wpabuf_alloc(WPS_OOB_DEVICE_PASSWORD_LEN);
    676 	if (pw == NULL)
    677 		return NULL;
    678 
    679 	if (random_get_bytes(wpabuf_put(pw, WPS_OOB_DEVICE_PASSWORD_LEN),
    680 			     WPS_OOB_DEVICE_PASSWORD_LEN) ||
    681 	    random_get_bytes((u8 *) &val, sizeof(val))) {
    682 		wpabuf_free(pw);
    683 		return NULL;
    684 	}
    685 
    686 	if (wps_nfc_gen_dh(pubkey, privkey) < 0) {
    687 		wpabuf_free(pw);
    688 		return NULL;
    689 	}
    690 
    691 	*id = 0x10 + val % 0xfff0;
    692 	wpabuf_free(*dev_pw);
    693 	*dev_pw = pw;
    694 
    695 	return wps_nfc_token_build(ndef, *id, *pubkey, *dev_pw);
    696 }
    697 
    698 
    699 struct wpabuf * wps_build_nfc_handover_req(struct wps_context *ctx,
    700 					   struct wpabuf *nfc_dh_pubkey)
    701 {
    702 	struct wpabuf *msg;
    703 	void *len;
    704 
    705 	if (ctx == NULL)
    706 		return NULL;
    707 
    708 	wpa_printf(MSG_DEBUG, "WPS: Building attributes for NFC connection "
    709 		   "handover request");
    710 
    711 	if (nfc_dh_pubkey == NULL) {
    712 		wpa_printf(MSG_DEBUG, "WPS: No NFC OOB Device Password "
    713 			   "configured");
    714 		return NULL;
    715 	}
    716 
    717 	msg = wpabuf_alloc(1000);
    718 	if (msg == NULL)
    719 		return msg;
    720 	len = wpabuf_put(msg, 2);
    721 
    722 	if (wps_build_oob_dev_pw(msg, DEV_PW_NFC_CONNECTION_HANDOVER,
    723 				 nfc_dh_pubkey, NULL, 0) ||
    724 	    wps_build_uuid_e(msg, ctx->uuid) ||
    725 	    wps_build_wfa_ext(msg, 0, NULL, 0)) {
    726 		wpabuf_free(msg);
    727 		return NULL;
    728 	}
    729 
    730 	WPA_PUT_BE16(len, wpabuf_len(msg) - 2);
    731 
    732 	return msg;
    733 }
    734 
    735 
    736 static int wps_build_ssid(struct wpabuf *msg, struct wps_context *wps)
    737 {
    738 	wpa_printf(MSG_DEBUG, "WPS:  * SSID");
    739 	wpa_hexdump_ascii(MSG_DEBUG, "WPS: SSID in Connection Handover Select",
    740 			  wps->ssid, wps->ssid_len);
    741 	wpabuf_put_be16(msg, ATTR_SSID);
    742 	wpabuf_put_be16(msg, wps->ssid_len);
    743 	wpabuf_put_data(msg, wps->ssid, wps->ssid_len);
    744 	return 0;
    745 }
    746 
    747 
    748 static int wps_build_ap_freq(struct wpabuf *msg, int freq)
    749 {
    750 	enum hostapd_hw_mode mode;
    751 	u8 channel, rf_band;
    752 	u16 ap_channel;
    753 
    754 	if (freq <= 0)
    755 		return 0;
    756 
    757 	mode = ieee80211_freq_to_chan(freq, &channel);
    758 	if (mode == NUM_HOSTAPD_MODES)
    759 		return 0; /* Unknown channel */
    760 
    761 	if (mode == HOSTAPD_MODE_IEEE80211G || mode == HOSTAPD_MODE_IEEE80211B)
    762 		rf_band = WPS_RF_24GHZ;
    763 	else if (mode == HOSTAPD_MODE_IEEE80211A)
    764 		rf_band = WPS_RF_50GHZ;
    765 	else if (mode == HOSTAPD_MODE_IEEE80211AD)
    766 		rf_band = WPS_RF_60GHZ;
    767 	else
    768 		return 0; /* Unknown band */
    769 	ap_channel = channel;
    770 
    771 	if (wps_build_rf_bands_attr(msg, rf_band) ||
    772 	    wps_build_ap_channel(msg, ap_channel))
    773 		return -1;
    774 
    775 	return 0;
    776 }
    777 
    778 
    779 struct wpabuf * wps_build_nfc_handover_sel(struct wps_context *ctx,
    780 					   struct wpabuf *nfc_dh_pubkey,
    781 					   const u8 *bssid, int freq)
    782 {
    783 	struct wpabuf *msg;
    784 	void *len;
    785 
    786 	if (ctx == NULL)
    787 		return NULL;
    788 
    789 	wpa_printf(MSG_DEBUG, "WPS: Building attributes for NFC connection "
    790 		   "handover select");
    791 
    792 	if (nfc_dh_pubkey == NULL) {
    793 		wpa_printf(MSG_DEBUG, "WPS: No NFC OOB Device Password "
    794 			   "configured");
    795 		return NULL;
    796 	}
    797 
    798 	msg = wpabuf_alloc(1000);
    799 	if (msg == NULL)
    800 		return msg;
    801 	len = wpabuf_put(msg, 2);
    802 
    803 	if (wps_build_oob_dev_pw(msg, DEV_PW_NFC_CONNECTION_HANDOVER,
    804 				 nfc_dh_pubkey, NULL, 0) ||
    805 	    wps_build_ssid(msg, ctx) ||
    806 	    wps_build_ap_freq(msg, freq) ||
    807 	    (bssid && wps_build_mac_addr(msg, bssid)) ||
    808 	    wps_build_wfa_ext(msg, 0, NULL, 0)) {
    809 		wpabuf_free(msg);
    810 		return NULL;
    811 	}
    812 
    813 	WPA_PUT_BE16(len, wpabuf_len(msg) - 2);
    814 
    815 	return msg;
    816 }
    817 
    818 
    819 struct wpabuf * wps_build_nfc_handover_req_p2p(struct wps_context *ctx,
    820 					       struct wpabuf *nfc_dh_pubkey)
    821 {
    822 	struct wpabuf *msg;
    823 
    824 	if (ctx == NULL)
    825 		return NULL;
    826 
    827 	wpa_printf(MSG_DEBUG, "WPS: Building attributes for NFC connection "
    828 		   "handover request (P2P)");
    829 
    830 	if (nfc_dh_pubkey == NULL) {
    831 		wpa_printf(MSG_DEBUG, "WPS: No NFC DH Public Key configured");
    832 		return NULL;
    833 	}
    834 
    835 	msg = wpabuf_alloc(1000);
    836 	if (msg == NULL)
    837 		return msg;
    838 
    839 	if (wps_build_manufacturer(&ctx->dev, msg) ||
    840 	    wps_build_model_name(&ctx->dev, msg) ||
    841 	    wps_build_model_number(&ctx->dev, msg) ||
    842 	    wps_build_oob_dev_pw(msg, DEV_PW_NFC_CONNECTION_HANDOVER,
    843 				 nfc_dh_pubkey, NULL, 0) ||
    844 	    wps_build_rf_bands(&ctx->dev, msg, 0) ||
    845 	    wps_build_serial_number(&ctx->dev, msg) ||
    846 	    wps_build_uuid_e(msg, ctx->uuid) ||
    847 	    wps_build_wfa_ext(msg, 0, NULL, 0)) {
    848 		wpabuf_free(msg);
    849 		return NULL;
    850 	}
    851 
    852 	return msg;
    853 }
    854 
    855 
    856 struct wpabuf * wps_build_nfc_handover_sel_p2p(struct wps_context *ctx,
    857 					       int nfc_dev_pw_id,
    858 					       struct wpabuf *nfc_dh_pubkey,
    859 					       struct wpabuf *nfc_dev_pw)
    860 {
    861 	struct wpabuf *msg;
    862 	const u8 *dev_pw;
    863 	size_t dev_pw_len;
    864 
    865 	if (ctx == NULL)
    866 		return NULL;
    867 
    868 	wpa_printf(MSG_DEBUG, "WPS: Building attributes for NFC connection "
    869 		   "handover select (P2P)");
    870 
    871 	if (nfc_dh_pubkey == NULL ||
    872 	    (nfc_dev_pw_id != DEV_PW_NFC_CONNECTION_HANDOVER &&
    873 	     nfc_dev_pw == NULL)) {
    874 		wpa_printf(MSG_DEBUG, "WPS: No NFC OOB Device Password "
    875 			   "configured");
    876 		return NULL;
    877 	}
    878 
    879 	msg = wpabuf_alloc(1000);
    880 	if (msg == NULL)
    881 		return msg;
    882 
    883 	if (nfc_dev_pw) {
    884 		dev_pw = wpabuf_head(nfc_dev_pw);
    885 		dev_pw_len = wpabuf_len(nfc_dev_pw);
    886 	} else {
    887 		dev_pw = NULL;
    888 		dev_pw_len = 0;
    889 	}
    890 
    891 	if (wps_build_manufacturer(&ctx->dev, msg) ||
    892 	    wps_build_model_name(&ctx->dev, msg) ||
    893 	    wps_build_model_number(&ctx->dev, msg) ||
    894 	    wps_build_oob_dev_pw(msg, nfc_dev_pw_id, nfc_dh_pubkey,
    895 				 dev_pw, dev_pw_len) ||
    896 	    wps_build_rf_bands(&ctx->dev, msg, 0) ||
    897 	    wps_build_serial_number(&ctx->dev, msg) ||
    898 	    wps_build_uuid_e(msg, ctx->uuid) ||
    899 	    wps_build_wfa_ext(msg, 0, NULL, 0)) {
    900 		wpabuf_free(msg);
    901 		return NULL;
    902 	}
    903 
    904 	return msg;
    905 }
    906 
    907 #endif /* CONFIG_WPS_NFC */
    908