contrib/wpa/src/wps/wps_common.c

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