src/wps/wps_attr_build.c

   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
  21 int 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 ||
  42                     wps->dev_pw_id == DEV_PW_NFC_CONNECTION_HANDOVER) &&
  43                    (wps->wps->ap ||
  44                     (wps->wps->ap_nfc_dh_pubkey &&
  45                      wps->wps->ap_nfc_dev_pw_id ==
  46                      DEV_PW_NFC_CONNECTION_HANDOVER &&
  47                      wps->dev_pw_id == DEV_PW_NFC_CONNECTION_HANDOVER)) &&
  48                    (wps->dev_pw_id == wps->wps->ap_nfc_dev_pw_id ||
  49                     wps->wps->ap_nfc_dh_pubkey)) {
  50                 wpa_printf(MSG_DEBUG, "WPS: Using NFC password token DH keys");
  51                 if (wps->wps->ap_nfc_dh_privkey == NULL) {
  52                         wpa_printf(MSG_DEBUG,
  53                                    "WPS: wps->wps->ap_nfc_dh_privkey == NULL");
  54                         return -1;
  55                 }
  56                 if (wps->wps->ap_nfc_dh_pubkey == NULL) {
  57                         wpa_printf(MSG_DEBUG,
  58                                    "WPS: wps->wps->ap_nfc_dh_pubkey == NULL");
  59                         return -1;
  60                 }
  61                 wps->dh_privkey = wpabuf_dup(wps->wps->ap_nfc_dh_privkey);
  62                 pubkey = wpabuf_dup(wps->wps->ap_nfc_dh_pubkey);
  63                 wps->dh_ctx = dh5_init_fixed(wps->dh_privkey, pubkey);
  64 #endif /* CONFIG_WPS_NFC */
  65         } else {
  66                 wpa_printf(MSG_DEBUG, "WPS: Generate new DH keys");
  67                 dh5_free(wps->dh_ctx);
  68                 wps->dh_ctx = dh5_init(&wps->dh_privkey, &pubkey);
  69                 pubkey = wpabuf_zeropad(pubkey, 192);
  70         }
  71         if (wps->dh_ctx == NULL || wps->dh_privkey == NULL || pubkey == NULL) {
  72                 wpa_printf(MSG_DEBUG, "WPS: Failed to initialize "
  73                            "Diffie-Hellman handshake");
  74                 wpabuf_free(pubkey);
  75                 return -1;
  76         }
  77         wpa_hexdump_buf_key(MSG_DEBUG, "WPS: DH Private Key", wps->dh_privkey);
  78         wpa_hexdump_buf(MSG_DEBUG, "WPS: DH own Public Key", pubkey);
  79
  80         wpabuf_put_be16(msg, ATTR_PUBLIC_KEY);
  81         wpabuf_put_be16(msg, wpabuf_len(pubkey));
  82         wpabuf_put_buf(msg, pubkey);
  83
  84         if (wps->registrar) {
  85                 wpabuf_free(wps->dh_pubkey_r);
  86                 wps->dh_pubkey_r = pubkey;
  87         } else {
  88                 wpabuf_free(wps->dh_pubkey_e);
  89                 wps->dh_pubkey_e = pubkey;
  90         }
  91
  92         return 0;
  93 }
  94
  95
  96 int wps_build_req_type(struct wpabuf *msg, enum wps_request_type type)
  97 {
  98         wpa_printf(MSG_DEBUG, "WPS:  * Request Type");
  99         wpabuf_put_be16(msg, ATTR_REQUEST_TYPE);
 100         wpabuf_put_be16(msg, 1);
 101         wpabuf_put_u8(msg, type);
 102         return 0;
 103 }
 104
 105
 106 int wps_build_resp_type(struct wpabuf *msg, enum wps_response_type type)
 107 {
 108         wpa_printf(MSG_DEBUG, "WPS:  * Response Type (%d)", type);
 109         wpabuf_put_be16(msg, ATTR_RESPONSE_TYPE);
 110         wpabuf_put_be16(msg, 1);
 111         wpabuf_put_u8(msg, type);
 112         return 0;
 113 }
 114
 115
 116 int wps_build_config_methods(struct wpabuf *msg, u16 methods)
 117 {
 118         wpa_printf(MSG_DEBUG, "WPS:  * Config Methods (%x)", methods);
 119         wpabuf_put_be16(msg, ATTR_CONFIG_METHODS);
 120         wpabuf_put_be16(msg, 2);
 121         wpabuf_put_be16(msg, methods);
 122         return 0;
 123 }
 124
 125
 126 int wps_build_uuid_e(struct wpabuf *msg, const u8 *uuid)
 127 {
 128         if (wpabuf_tailroom(msg) < 4 + WPS_UUID_LEN)
 129                 return -1;
 130         wpa_printf(MSG_DEBUG, "WPS:  * UUID-E");
 131         wpabuf_put_be16(msg, ATTR_UUID_E);
 132         wpabuf_put_be16(msg, WPS_UUID_LEN);
 133         wpabuf_put_data(msg, uuid, WPS_UUID_LEN);
 134         return 0;
 135 }
 136
 137
 138 int wps_build_dev_password_id(struct wpabuf *msg, u16 id)
 139 {
 140         wpa_printf(MSG_DEBUG, "WPS:  * Device Password ID (%d)", id);
 141         wpabuf_put_be16(msg, ATTR_DEV_PASSWORD_ID);
 142         wpabuf_put_be16(msg, 2);
 143         wpabuf_put_be16(msg, id);
 144         return 0;
 145 }
 146
 147
 148 int wps_build_config_error(struct wpabuf *msg, u16 err)
 149 {
 150         wpa_printf(MSG_DEBUG, "WPS:  * Configuration Error (%d)", err);
 151         wpabuf_put_be16(msg, ATTR_CONFIG_ERROR);
 152         wpabuf_put_be16(msg, 2);
 153         wpabuf_put_be16(msg, err);
 154         return 0;
 155 }
 156
 157
 158 int wps_build_authenticator(struct wps_data *wps, struct wpabuf *msg)
 159 {
 160         u8 hash[SHA256_MAC_LEN];
 161         const u8 *addr[2];
 162         size_t len[2];
 163
 164         if (wps->last_msg == NULL) {
 165                 wpa_printf(MSG_DEBUG, "WPS: Last message not available for "
 166                            "building authenticator");
 167                 return -1;
 168         }
 169
 170         /* Authenticator = HMAC-SHA256_AuthKey(M_prev || M_curr*)
 171          * (M_curr* is M_curr without the Authenticator attribute)
 172          */
 173         addr[0] = wpabuf_head(wps->last_msg);
 174         len[0] = wpabuf_len(wps->last_msg);
 175         addr[1] = wpabuf_head(msg);
 176         len[1] = wpabuf_len(msg);
 177         hmac_sha256_vector(wps->authkey, WPS_AUTHKEY_LEN, 2, addr, len, hash);
 178
 179         wpa_printf(MSG_DEBUG, "WPS:  * Authenticator");
 180         wpabuf_put_be16(msg, ATTR_AUTHENTICATOR);
 181         wpabuf_put_be16(msg, WPS_AUTHENTICATOR_LEN);
 182         wpabuf_put_data(msg, hash, WPS_AUTHENTICATOR_LEN);
 183
 184         return 0;
 185 }
 186
 187
 188 int wps_build_version(struct wpabuf *msg)
 189 {
 190         /*
 191          * Note: This attribute is deprecated and set to hardcoded 0x10 for
 192          * backwards compatibility reasons. The real version negotiation is
 193          * done with Version2.
 194          */
 195         if (wpabuf_tailroom(msg) < 5)
 196                 return -1;
 197         wpa_printf(MSG_DEBUG, "WPS:  * Version (hardcoded 0x10)");
 198         wpabuf_put_be16(msg, ATTR_VERSION);
 199         wpabuf_put_be16(msg, 1);
 200         wpabuf_put_u8(msg, 0x10);
 201         return 0;
 202 }
 203
 204
 205 int wps_build_wfa_ext(struct wpabuf *msg, int req_to_enroll,
 206                       const u8 *auth_macs, size_t auth_macs_count)
 207 {
 208         u8 *len;
 209
 210 #ifdef CONFIG_WPS_TESTING
 211         if (WPS_VERSION == 0x10)
 212                 return 0;
 213 #endif /* CONFIG_WPS_TESTING */
 214
 215         if (wpabuf_tailroom(msg) <
 216             7 + 3 + (req_to_enroll ? 3 : 0) +
 217             (auth_macs ? 2 + auth_macs_count * ETH_ALEN : 0))
 218                 return -1;
 219         wpabuf_put_be16(msg, ATTR_VENDOR_EXT);
 220         len = wpabuf_put(msg, 2); /* to be filled */
 221         wpabuf_put_be24(msg, WPS_VENDOR_ID_WFA);
 222
 223         wpa_printf(MSG_DEBUG, "WPS:  * Version2 (0x%x)", WPS_VERSION);
 224         wpabuf_put_u8(msg, WFA_ELEM_VERSION2);
 225         wpabuf_put_u8(msg, 1);
 226         wpabuf_put_u8(msg, WPS_VERSION);
 227
 228         if (req_to_enroll) {
 229                 wpa_printf(MSG_DEBUG, "WPS:  * Request to Enroll (1)");
 230                 wpabuf_put_u8(msg, WFA_ELEM_REQUEST_TO_ENROLL);
 231                 wpabuf_put_u8(msg, 1);
 232                 wpabuf_put_u8(msg, 1);
 233         }
 234
 235         if (auth_macs && auth_macs_count) {
 236                 size_t i;
 237                 wpa_printf(MSG_DEBUG, "WPS:  * AuthorizedMACs (count=%d)",
 238                            (int) auth_macs_count);
 239                 wpabuf_put_u8(msg, WFA_ELEM_AUTHORIZEDMACS);
 240                 wpabuf_put_u8(msg, auth_macs_count * ETH_ALEN);
 241                 wpabuf_put_data(msg, auth_macs, auth_macs_count * ETH_ALEN);
 242                 for (i = 0; i < auth_macs_count; i++)
 243                         wpa_printf(MSG_DEBUG, "WPS:    AuthorizedMAC: " MACSTR,
 244                                    MAC2STR(&auth_macs[i * ETH_ALEN]));
 245         }
 246
 247         WPA_PUT_BE16(len, (u8 *) wpabuf_put(msg, 0) - len - 2);
 248
 249 #ifdef CONFIG_WPS_TESTING
 250         if (WPS_VERSION > 0x20) {
 251                 if (wpabuf_tailroom(msg) < 5)
 252                         return -1;
 253                 wpa_printf(MSG_DEBUG, "WPS:  * Extensibility Testing - extra "
 254                            "attribute");
 255                 wpabuf_put_be16(msg, ATTR_EXTENSIBILITY_TEST);
 256                 wpabuf_put_be16(msg, 1);
 257                 wpabuf_put_u8(msg, 42);
 258         }
 259 #endif /* CONFIG_WPS_TESTING */
 260         return 0;
 261 }
 262
 263
 264 int wps_build_msg_type(struct wpabuf *msg, enum wps_msg_type msg_type)
 265 {
 266         wpa_printf(MSG_DEBUG, "WPS:  * Message Type (%d)", msg_type);
 267         wpabuf_put_be16(msg, ATTR_MSG_TYPE);
 268         wpabuf_put_be16(msg, 1);
 269         wpabuf_put_u8(msg, msg_type);
 270         return 0;
 271 }
 272
 273
 274 int wps_build_enrollee_nonce(struct wps_data *wps, struct wpabuf *msg)
 275 {
 276         wpa_printf(MSG_DEBUG, "WPS:  * Enrollee Nonce");
 277         wpabuf_put_be16(msg, ATTR_ENROLLEE_NONCE);
 278         wpabuf_put_be16(msg, WPS_NONCE_LEN);
 279         wpabuf_put_data(msg, wps->nonce_e, WPS_NONCE_LEN);
 280         return 0;
 281 }
 282
 283
 284 int wps_build_registrar_nonce(struct wps_data *wps, struct wpabuf *msg)
 285 {
 286         wpa_printf(MSG_DEBUG, "WPS:  * Registrar Nonce");
 287         wpabuf_put_be16(msg, ATTR_REGISTRAR_NONCE);
 288         wpabuf_put_be16(msg, WPS_NONCE_LEN);
 289         wpabuf_put_data(msg, wps->nonce_r, WPS_NONCE_LEN);
 290         return 0;
 291 }
 292
 293
 294 int wps_build_auth_type_flags(struct wps_data *wps, struct wpabuf *msg)
 295 {
 296         u16 auth_types = WPS_AUTH_TYPES;
 297         /* WPA/WPA2-Enterprise enrollment not supported through WPS */
 298         auth_types &= ~WPS_AUTH_WPA;
 299         auth_types &= ~WPS_AUTH_WPA2;
 300         auth_types &= ~WPS_AUTH_SHARED;
 301         wpa_printf(MSG_DEBUG, "WPS:  * Authentication Type Flags");
 302         wpabuf_put_be16(msg, ATTR_AUTH_TYPE_FLAGS);
 303         wpabuf_put_be16(msg, 2);
 304         wpabuf_put_be16(msg, auth_types);
 305         return 0;
 306 }
 307
 308
 309 int wps_build_encr_type_flags(struct wps_data *wps, struct wpabuf *msg)
 310 {
 311         u16 encr_types = WPS_ENCR_TYPES;
 312         encr_types &= ~WPS_ENCR_WEP;
 313         wpa_printf(MSG_DEBUG, "WPS:  * Encryption Type Flags");
 314         wpabuf_put_be16(msg, ATTR_ENCR_TYPE_FLAGS);
 315         wpabuf_put_be16(msg, 2);
 316         wpabuf_put_be16(msg, encr_types);
 317         return 0;
 318 }
 319
 320
 321 int wps_build_conn_type_flags(struct wps_data *wps, struct wpabuf *msg)
 322 {
 323         wpa_printf(MSG_DEBUG, "WPS:  * Connection Type Flags");
 324         wpabuf_put_be16(msg, ATTR_CONN_TYPE_FLAGS);
 325         wpabuf_put_be16(msg, 1);
 326         wpabuf_put_u8(msg, WPS_CONN_ESS);
 327         return 0;
 328 }
 329
 330
 331 int wps_build_assoc_state(struct wps_data *wps, struct wpabuf *msg)
 332 {
 333         wpa_printf(MSG_DEBUG, "WPS:  * Association State");
 334         wpabuf_put_be16(msg, ATTR_ASSOC_STATE);
 335         wpabuf_put_be16(msg, 2);
 336         wpabuf_put_be16(msg, WPS_ASSOC_NOT_ASSOC);
 337         return 0;
 338 }
 339
 340
 341 int wps_build_key_wrap_auth(struct wps_data *wps, struct wpabuf *msg)
 342 {
 343         u8 hash[SHA256_MAC_LEN];
 344
 345         wpa_printf(MSG_DEBUG, "WPS:  * Key Wrap Authenticator");
 346         hmac_sha256(wps->authkey, WPS_AUTHKEY_LEN, wpabuf_head(msg),
 347                     wpabuf_len(msg), hash);
 348
 349         wpabuf_put_be16(msg, ATTR_KEY_WRAP_AUTH);
 350         wpabuf_put_be16(msg, WPS_KWA_LEN);
 351         wpabuf_put_data(msg, hash, WPS_KWA_LEN);
 352         return 0;
 353 }
 354
 355
 356 int wps_build_encr_settings(struct wps_data *wps, struct wpabuf *msg,
 357                             struct wpabuf *plain)
 358 {
 359         size_t pad_len;
 360         const size_t block_size = 16;
 361         u8 *iv, *data;
 362
 363         wpa_printf(MSG_DEBUG, "WPS:  * Encrypted Settings");
 364
 365         /* PKCS#5 v2.0 pad */
 366         pad_len = block_size - wpabuf_len(plain) % block_size;
 367         os_memset(wpabuf_put(plain, pad_len), pad_len, pad_len);
 368
 369         wpabuf_put_be16(msg, ATTR_ENCR_SETTINGS);
 370         wpabuf_put_be16(msg, block_size + wpabuf_len(plain));
 371
 372         iv = wpabuf_put(msg, block_size);
 373         if (random_get_bytes(iv, block_size) < 0)
 374                 return -1;
 375
 376         data = wpabuf_put(msg, 0);
 377         wpabuf_put_buf(msg, plain);
 378         if (aes_128_cbc_encrypt(wps->keywrapkey, iv, data, wpabuf_len(plain)))
 379                 return -1;
 380
 381         return 0;
 382 }
 383
 384
 385 #ifdef CONFIG_WPS_OOB
 386 int wps_build_oob_dev_pw(struct wpabuf *msg, u16 dev_pw_id,
 387                          const struct wpabuf *pubkey, const u8 *dev_pw,
 388                          size_t dev_pw_len)
 389 {
 390         size_t hash_len;
 391         const u8 *addr[1];
 392         u8 pubkey_hash[WPS_HASH_LEN];
 393
 394         wpa_printf(MSG_DEBUG, "WPS:  * OOB Device Password (dev_pw_id=%u)",
 395                    dev_pw_id);
 396         addr[0] = wpabuf_head(pubkey);
 397         hash_len = wpabuf_len(pubkey);
 398         sha256_vector(1, addr, &hash_len, pubkey_hash);
 399 #ifdef CONFIG_WPS_TESTING
 400         if (wps_corrupt_pkhash) {
 401                 wpa_hexdump(MSG_DEBUG, "WPS: Real Public Key Hash",
 402                             pubkey_hash, WPS_OOB_PUBKEY_HASH_LEN);
 403                 wpa_printf(MSG_INFO, "WPS: Testing - corrupt public key hash");
 404                 pubkey_hash[WPS_OOB_PUBKEY_HASH_LEN - 2]++;
 405         }
 406 #endif /* CONFIG_WPS_TESTING */
 407
 408         wpabuf_put_be16(msg, ATTR_OOB_DEVICE_PASSWORD);
 409         wpabuf_put_be16(msg, WPS_OOB_PUBKEY_HASH_LEN + 2 + dev_pw_len);
 410         wpa_hexdump(MSG_DEBUG, "WPS: Public Key Hash",
 411                     pubkey_hash, WPS_OOB_PUBKEY_HASH_LEN);
 412         wpabuf_put_data(msg, pubkey_hash, WPS_OOB_PUBKEY_HASH_LEN);
 413         wpabuf_put_be16(msg, dev_pw_id);
 414         if (dev_pw) {
 415                 wpa_hexdump_key(MSG_DEBUG, "WPS: OOB Device Password",
 416                                 dev_pw, dev_pw_len);
 417                 wpabuf_put_data(msg, dev_pw, dev_pw_len);
 418         }
 419
 420         return 0;
 421 }
 422 #endif /* CONFIG_WPS_OOB */
 423
 424
 425 /* Encapsulate WPS IE data with one (or more, if needed) IE headers */
 426 struct wpabuf * wps_ie_encapsulate(struct wpabuf *data)
 427 {
 428         struct wpabuf *ie;
 429         const u8 *pos, *end;
 430
 431         ie = wpabuf_alloc(wpabuf_len(data) + 100);
 432         if (ie == NULL) {
 433                 wpabuf_free(data);
 434                 return NULL;
 435         }
 436
 437         pos = wpabuf_head(data);
 438         end = pos + wpabuf_len(data);
 439
 440         while (end > pos) {
 441                 size_t frag_len = end - pos;
 442                 if (frag_len > 251)
 443                         frag_len = 251;
 444                 wpabuf_put_u8(ie, WLAN_EID_VENDOR_SPECIFIC);
 445                 wpabuf_put_u8(ie, 4 + frag_len);
 446                 wpabuf_put_be32(ie, WPS_DEV_OUI_WFA);
 447                 wpabuf_put_data(ie, pos, frag_len);
 448                 pos += frag_len;
 449         }
 450
 451         wpabuf_free(data);
 452
 453         return ie;
 454 }
 455
 456
 457 int wps_build_mac_addr(struct wpabuf *msg, const u8 *addr)
 458 {
 459         wpa_printf(MSG_DEBUG, "WPS:  * MAC Address (" MACSTR ")",
 460                    MAC2STR(addr));
 461         wpabuf_put_be16(msg, ATTR_MAC_ADDR);
 462         wpabuf_put_be16(msg, ETH_ALEN);
 463         wpabuf_put_data(msg, addr, ETH_ALEN);
 464         return 0;
 465 }
 466
 467
 468 int wps_build_rf_bands_attr(struct wpabuf *msg, u8 rf_bands)
 469 {
 470         wpa_printf(MSG_DEBUG, "WPS:  * RF Bands (%x)", rf_bands);
 471         wpabuf_put_be16(msg, ATTR_RF_BANDS);
 472         wpabuf_put_be16(msg, 1);
 473         wpabuf_put_u8(msg, rf_bands);
 474         return 0;
 475 }
 476
 477
 478 int wps_build_ap_channel(struct wpabuf *msg, u16 ap_channel)
 479 {
 480         wpa_printf(MSG_DEBUG, "WPS:  * AP Channel (%u)", ap_channel);
 481         wpabuf_put_be16(msg, ATTR_AP_CHANNEL);
 482         wpabuf_put_be16(msg, 2);
 483         wpabuf_put_be16(msg, ap_channel);
 484         return 0;
 485 }