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 "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 565 566 struct wpabuf * wps_nfc_token_build(int ndef, int id, struct wpabuf *pubkey, 567 struct wpabuf *dev_pw) 568 { 569 struct wpabuf *ret; 570 571 if (pubkey == NULL || dev_pw == NULL) 572 return NULL; 573 574 ret = wps_build_nfc_pw_token(id, pubkey, dev_pw); 575 if (ndef && ret) { 576 struct wpabuf *tmp; 577 tmp = ndef_build_wifi(ret); 578 wpabuf_free(ret); 579 if (tmp == NULL) 580 return NULL; 581 ret = tmp; 582 } 583 584 return ret; 585 } 586 587 588 struct wpabuf * wps_nfc_token_gen(int ndef, int *id, struct wpabuf **pubkey, 589 struct wpabuf **privkey, 590 struct wpabuf **dev_pw) 591 { 592 struct wpabuf *priv = NULL, *pub = NULL, *pw; 593 void *dh_ctx; 594 u16 val; 595 596 pw = wpabuf_alloc(WPS_OOB_DEVICE_PASSWORD_LEN); 597 if (pw == NULL) 598 return NULL; 599 600 if (random_get_bytes(wpabuf_put(pw, WPS_OOB_DEVICE_PASSWORD_LEN), 601 WPS_OOB_DEVICE_PASSWORD_LEN) || 602 random_get_bytes((u8 *) &val, sizeof(val))) { 603 wpabuf_free(pw); 604 return NULL; 605 } 606 607 dh_ctx = dh5_init(&priv, &pub); 608 if (dh_ctx == NULL) { 609 wpabuf_free(pw); 610 return NULL; 611 } 612 dh5_free(dh_ctx); 613 614 *id = 0x10 + val % 0xfff0; 615 wpabuf_free(*pubkey); 616 *pubkey = pub; 617 wpabuf_free(*privkey); 618 *privkey = priv; 619 wpabuf_free(*dev_pw); 620 *dev_pw = pw; 621 622 return wps_nfc_token_build(ndef, *id, *pubkey, *dev_pw); 623 } 624 625 #endif /* CONFIG_WPS_NFC */ 626
