wps_common.c revision 4b06059785b935dd1f4f09314e4e12c417d2c6a4
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 21void 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 59int 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 129void 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 149struct 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 */ 206unsigned 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 */ 225unsigned 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 */ 235unsigned 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 252int 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 268void 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 284void 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 293void 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 307void 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 316void 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 327struct 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 os_free(data.new_psk); 347 wpabuf_free(plain); 348 return NULL; 349 } 350 351 if (wps->wps_state == WPS_STATE_NOT_CONFIGURED && data.new_psk && 352 wps->ap) { 353 struct wps_credential cred; 354 355 wpa_printf(MSG_DEBUG, "WPS: Moving to Configured state based " 356 "on credential token generation"); 357 358 os_memset(&cred, 0, sizeof(cred)); 359 os_memcpy(cred.ssid, wps->ssid, wps->ssid_len); 360 cred.ssid_len = wps->ssid_len; 361 cred.auth_type = WPS_AUTH_WPAPSK | WPS_AUTH_WPA2PSK; 362 cred.encr_type = WPS_ENCR_TKIP | WPS_ENCR_AES; 363 os_memcpy(cred.key, data.new_psk, data.new_psk_len); 364 cred.key_len = data.new_psk_len; 365 366 wps->wps_state = WPS_STATE_CONFIGURED; 367 wpa_hexdump_ascii_key(MSG_DEBUG, 368 "WPS: Generated random passphrase", 369 data.new_psk, data.new_psk_len); 370 if (wps->cred_cb) 371 wps->cred_cb(wps->cb_ctx, &cred); 372 } 373 374 os_free(data.new_psk); 375 376 return plain; 377} 378 379 380struct wpabuf * wps_build_nfc_pw_token(u16 dev_pw_id, 381 const struct wpabuf *pubkey, 382 const struct wpabuf *dev_pw) 383{ 384 struct wpabuf *data; 385 386 data = wpabuf_alloc(200); 387 if (data == NULL) 388 return NULL; 389 390 if (wps_build_version(data) || 391 wps_build_oob_dev_pw(data, dev_pw_id, pubkey, 392 wpabuf_head(dev_pw), wpabuf_len(dev_pw)) || 393 wps_build_wfa_ext(data, 0, NULL, 0)) { 394 wpa_printf(MSG_ERROR, "WPS: Failed to build NFC password " 395 "token"); 396 wpabuf_free(data); 397 return NULL; 398 } 399 400 return data; 401} 402 403 404int wps_oob_use_cred(struct wps_context *wps, struct wps_parse_attr *attr) 405{ 406 struct wpabuf msg; 407 size_t i; 408 409 for (i = 0; i < attr->num_cred; i++) { 410 struct wps_credential local_cred; 411 struct wps_parse_attr cattr; 412 413 os_memset(&local_cred, 0, sizeof(local_cred)); 414 wpabuf_set(&msg, attr->cred[i], attr->cred_len[i]); 415 if (wps_parse_msg(&msg, &cattr) < 0 || 416 wps_process_cred(&cattr, &local_cred)) { 417 wpa_printf(MSG_ERROR, "WPS: Failed to parse OOB " 418 "credential"); 419 return -1; 420 } 421 wps->cred_cb(wps->cb_ctx, &local_cred); 422 } 423 424 return 0; 425} 426 427 428#endif /* CONFIG_WPS_OOB */ 429 430 431int wps_dev_type_str2bin(const char *str, u8 dev_type[WPS_DEV_TYPE_LEN]) 432{ 433 const char *pos; 434 435 /* <categ>-<OUI>-<subcateg> */ 436 WPA_PUT_BE16(dev_type, atoi(str)); 437 pos = os_strchr(str, '-'); 438 if (pos == NULL) 439 return -1; 440 pos++; 441 if (hexstr2bin(pos, &dev_type[2], 4)) 442 return -1; 443 pos = os_strchr(pos, '-'); 444 if (pos == NULL) 445 return -1; 446 pos++; 447 WPA_PUT_BE16(&dev_type[6], atoi(pos)); 448 449 450 return 0; 451} 452 453 454char * wps_dev_type_bin2str(const u8 dev_type[WPS_DEV_TYPE_LEN], char *buf, 455 size_t buf_len) 456{ 457 int ret; 458 459 ret = os_snprintf(buf, buf_len, "%u-%08X-%u", 460 WPA_GET_BE16(dev_type), WPA_GET_BE32(&dev_type[2]), 461 WPA_GET_BE16(&dev_type[6])); 462 if (ret < 0 || (unsigned int) ret >= buf_len) 463 return NULL; 464 465 return buf; 466} 467 468 469void uuid_gen_mac_addr(const u8 *mac_addr, u8 *uuid) 470{ 471 const u8 *addr[2]; 472 size_t len[2]; 473 u8 hash[SHA1_MAC_LEN]; 474 u8 nsid[16] = { 475 0x52, 0x64, 0x80, 0xf8, 476 0xc9, 0x9b, 477 0x4b, 0xe5, 478 0xa6, 0x55, 479 0x58, 0xed, 0x5f, 0x5d, 0x60, 0x84 480 }; 481 482 addr[0] = nsid; 483 len[0] = sizeof(nsid); 484 addr[1] = mac_addr; 485 len[1] = 6; 486 sha1_vector(2, addr, len, hash); 487 os_memcpy(uuid, hash, 16); 488 489 /* Version: 5 = named-based version using SHA-1 */ 490 uuid[6] = (5 << 4) | (uuid[6] & 0x0f); 491 492 /* Variant specified in RFC 4122 */ 493 uuid[8] = 0x80 | (uuid[8] & 0x3f); 494} 495 496 497u16 wps_config_methods_str2bin(const char *str) 498{ 499 u16 methods = 0; 500 501 if (str == NULL) { 502 /* Default to enabling methods based on build configuration */ 503 methods |= WPS_CONFIG_DISPLAY | WPS_CONFIG_KEYPAD; 504#ifdef CONFIG_WPS2 505 methods |= WPS_CONFIG_VIRT_DISPLAY; 506#endif /* CONFIG_WPS2 */ 507#ifdef CONFIG_WPS_NFC 508 methods |= WPS_CONFIG_NFC_INTERFACE; 509#endif /* CONFIG_WPS_NFC */ 510 } else { 511 if (os_strstr(str, "ethernet")) 512 methods |= WPS_CONFIG_ETHERNET; 513 if (os_strstr(str, "label")) 514 methods |= WPS_CONFIG_LABEL; 515 if (os_strstr(str, "display")) 516 methods |= WPS_CONFIG_DISPLAY; 517 if (os_strstr(str, "ext_nfc_token")) 518 methods |= WPS_CONFIG_EXT_NFC_TOKEN; 519 if (os_strstr(str, "int_nfc_token")) 520 methods |= WPS_CONFIG_INT_NFC_TOKEN; 521 if (os_strstr(str, "nfc_interface")) 522 methods |= WPS_CONFIG_NFC_INTERFACE; 523 if (os_strstr(str, "push_button")) 524 methods |= WPS_CONFIG_PUSHBUTTON; 525 if (os_strstr(str, "keypad")) 526 methods |= WPS_CONFIG_KEYPAD; 527#ifdef CONFIG_WPS2 528 if (os_strstr(str, "virtual_display")) 529 methods |= WPS_CONFIG_VIRT_DISPLAY; 530 if (os_strstr(str, "physical_display")) 531 methods |= WPS_CONFIG_PHY_DISPLAY; 532 if (os_strstr(str, "virtual_push_button")) 533 methods |= WPS_CONFIG_VIRT_PUSHBUTTON; 534 if (os_strstr(str, "physical_push_button")) 535 methods |= WPS_CONFIG_PHY_PUSHBUTTON; 536#endif /* CONFIG_WPS2 */ 537 } 538 539 return methods; 540} 541 542 543struct wpabuf * wps_build_wsc_ack(struct wps_data *wps) 544{ 545 struct wpabuf *msg; 546 547 wpa_printf(MSG_DEBUG, "WPS: Building Message WSC_ACK"); 548 549 msg = wpabuf_alloc(1000); 550 if (msg == NULL) 551 return NULL; 552 553 if (wps_build_version(msg) || 554 wps_build_msg_type(msg, WPS_WSC_ACK) || 555 wps_build_enrollee_nonce(wps, msg) || 556 wps_build_registrar_nonce(wps, msg) || 557 wps_build_wfa_ext(msg, 0, NULL, 0)) { 558 wpabuf_free(msg); 559 return NULL; 560 } 561 562 return msg; 563} 564 565 566struct wpabuf * wps_build_wsc_nack(struct wps_data *wps) 567{ 568 struct wpabuf *msg; 569 570 wpa_printf(MSG_DEBUG, "WPS: Building Message WSC_NACK"); 571 572 msg = wpabuf_alloc(1000); 573 if (msg == NULL) 574 return NULL; 575 576 if (wps_build_version(msg) || 577 wps_build_msg_type(msg, WPS_WSC_NACK) || 578 wps_build_enrollee_nonce(wps, msg) || 579 wps_build_registrar_nonce(wps, msg) || 580 wps_build_config_error(msg, wps->config_error) || 581 wps_build_wfa_ext(msg, 0, NULL, 0)) { 582 wpabuf_free(msg); 583 return NULL; 584 } 585 586 return msg; 587} 588 589 590#ifdef CONFIG_WPS_NFC 591 592struct wpabuf * wps_nfc_token_build(int ndef, int id, struct wpabuf *pubkey, 593 struct wpabuf *dev_pw) 594{ 595 struct wpabuf *ret; 596 597 if (pubkey == NULL || dev_pw == NULL) 598 return NULL; 599 600 ret = wps_build_nfc_pw_token(id, pubkey, dev_pw); 601 if (ndef && ret) { 602 struct wpabuf *tmp; 603 tmp = ndef_build_wifi(ret); 604 wpabuf_free(ret); 605 if (tmp == NULL) 606 return NULL; 607 ret = tmp; 608 } 609 610 return ret; 611} 612 613 614struct wpabuf * wps_nfc_token_gen(int ndef, int *id, struct wpabuf **pubkey, 615 struct wpabuf **privkey, 616 struct wpabuf **dev_pw) 617{ 618 struct wpabuf *priv = NULL, *pub = NULL, *pw; 619 void *dh_ctx; 620 u16 val; 621 622 pw = wpabuf_alloc(WPS_OOB_DEVICE_PASSWORD_LEN); 623 if (pw == NULL) 624 return NULL; 625 626 if (random_get_bytes(wpabuf_put(pw, WPS_OOB_DEVICE_PASSWORD_LEN), 627 WPS_OOB_DEVICE_PASSWORD_LEN) || 628 random_get_bytes((u8 *) &val, sizeof(val))) { 629 wpabuf_free(pw); 630 return NULL; 631 } 632 633 dh_ctx = dh5_init(&priv, &pub); 634 if (dh_ctx == NULL) { 635 wpabuf_free(pw); 636 return NULL; 637 } 638 dh5_free(dh_ctx); 639 640 *id = 0x10 + val % 0xfff0; 641 wpabuf_free(*pubkey); 642 *pubkey = pub; 643 wpabuf_free(*privkey); 644 *privkey = priv; 645 wpabuf_free(*dev_pw); 646 *dev_pw = pw; 647 648 return wps_nfc_token_build(ndef, *id, *pubkey, *dev_pw); 649} 650 651#endif /* CONFIG_WPS_NFC */ 652