1 /* 2 * WPA Supplicant - Mesh RSN routines 3 * Copyright (c) 2013-2014, cozybit, Inc. All rights reserved. 4 * 5 * This software may be distributed under the terms of the BSD license. 6 * See README for more details. 7 */ 8 9 #include "utils/includes.h" 10 11 #include "utils/common.h" 12 #include "utils/eloop.h" 13 #include "crypto/sha256.h" 14 #include "crypto/random.h" 15 #include "crypto/aes.h" 16 #include "crypto/aes_siv.h" 17 #include "rsn_supp/wpa.h" 18 #include "ap/hostapd.h" 19 #include "ap/wpa_auth.h" 20 #include "ap/sta_info.h" 21 #include "ap/ieee802_11.h" 22 #include "wpa_supplicant_i.h" 23 #include "driver_i.h" 24 #include "wpas_glue.h" 25 #include "mesh_mpm.h" 26 #include "mesh_rsn.h" 27 28 #define MESH_AUTH_TIMEOUT 10 29 #define MESH_AUTH_RETRY 3 30 31 void mesh_auth_timer(void *eloop_ctx, void *user_data) 32 { 33 struct wpa_supplicant *wpa_s = eloop_ctx; 34 struct sta_info *sta = user_data; 35 struct hostapd_data *hapd; 36 37 if (sta->sae->state != SAE_ACCEPTED) { 38 wpa_printf(MSG_DEBUG, "AUTH: Re-authenticate with " MACSTR 39 " (attempt %d) ", 40 MAC2STR(sta->addr), sta->sae_auth_retry); 41 wpa_msg(wpa_s, MSG_INFO, MESH_SAE_AUTH_FAILURE "addr=" MACSTR, 42 MAC2STR(sta->addr)); 43 if (sta->sae_auth_retry < MESH_AUTH_RETRY) { 44 mesh_rsn_auth_sae_sta(wpa_s, sta); 45 } else { 46 hapd = wpa_s->ifmsh->bss[0]; 47 48 if (sta->sae_auth_retry > MESH_AUTH_RETRY) { 49 ap_free_sta(hapd, sta); 50 return; 51 } 52 53 /* block the STA if exceeded the number of attempts */ 54 wpa_mesh_set_plink_state(wpa_s, sta, PLINK_BLOCKED); 55 sta->sae->state = SAE_NOTHING; 56 wpa_msg(wpa_s, MSG_INFO, MESH_SAE_AUTH_BLOCKED "addr=" 57 MACSTR " duration=%d", 58 MAC2STR(sta->addr), 59 hapd->conf->ap_max_inactivity); 60 } 61 sta->sae_auth_retry++; 62 } 63 } 64 65 66 static void auth_logger(void *ctx, const u8 *addr, logger_level level, 67 const char *txt) 68 { 69 if (addr) 70 wpa_printf(MSG_DEBUG, "AUTH: " MACSTR " - %s", 71 MAC2STR(addr), txt); 72 else 73 wpa_printf(MSG_DEBUG, "AUTH: %s", txt); 74 } 75 76 77 static const u8 *auth_get_psk(void *ctx, const u8 *addr, 78 const u8 *p2p_dev_addr, const u8 *prev_psk) 79 { 80 struct mesh_rsn *mesh_rsn = ctx; 81 struct hostapd_data *hapd = mesh_rsn->wpa_s->ifmsh->bss[0]; 82 struct sta_info *sta = ap_get_sta(hapd, addr); 83 84 wpa_printf(MSG_DEBUG, "AUTH: %s (addr=" MACSTR " prev_psk=%p)", 85 __func__, MAC2STR(addr), prev_psk); 86 87 if (sta && sta->auth_alg == WLAN_AUTH_SAE) { 88 if (!sta->sae || prev_psk) 89 return NULL; 90 return sta->sae->pmk; 91 } 92 93 return NULL; 94 } 95 96 97 static int auth_set_key(void *ctx, int vlan_id, enum wpa_alg alg, 98 const u8 *addr, int idx, u8 *key, size_t key_len) 99 { 100 struct mesh_rsn *mesh_rsn = ctx; 101 u8 seq[6]; 102 103 os_memset(seq, 0, sizeof(seq)); 104 105 if (addr) { 106 wpa_printf(MSG_DEBUG, "AUTH: %s(alg=%d addr=" MACSTR 107 " key_idx=%d)", 108 __func__, alg, MAC2STR(addr), idx); 109 } else { 110 wpa_printf(MSG_DEBUG, "AUTH: %s(alg=%d key_idx=%d)", 111 __func__, alg, idx); 112 } 113 wpa_hexdump_key(MSG_DEBUG, "AUTH: set_key - key", key, key_len); 114 115 return wpa_drv_set_key(mesh_rsn->wpa_s, alg, addr, idx, 116 1, seq, 6, key, key_len); 117 } 118 119 120 static int auth_start_ampe(void *ctx, const u8 *addr) 121 { 122 struct mesh_rsn *mesh_rsn = ctx; 123 struct hostapd_data *hapd; 124 struct sta_info *sta; 125 126 if (mesh_rsn->wpa_s->current_ssid->mode != WPAS_MODE_MESH) 127 return -1; 128 129 hapd = mesh_rsn->wpa_s->ifmsh->bss[0]; 130 sta = ap_get_sta(hapd, addr); 131 if (sta) 132 eloop_cancel_timeout(mesh_auth_timer, mesh_rsn->wpa_s, sta); 133 134 mesh_mpm_auth_peer(mesh_rsn->wpa_s, addr); 135 return 0; 136 } 137 138 139 static int __mesh_rsn_auth_init(struct mesh_rsn *rsn, const u8 *addr, 140 enum mfp_options ieee80211w) 141 { 142 struct wpa_auth_config conf; 143 static const struct wpa_auth_callbacks cb = { 144 .logger = auth_logger, 145 .get_psk = auth_get_psk, 146 .set_key = auth_set_key, 147 .start_ampe = auth_start_ampe, 148 }; 149 u8 seq[6] = {}; 150 151 wpa_printf(MSG_DEBUG, "AUTH: Initializing group state machine"); 152 153 os_memset(&conf, 0, sizeof(conf)); 154 conf.wpa = WPA_PROTO_RSN; 155 conf.wpa_key_mgmt = WPA_KEY_MGMT_SAE; 156 conf.wpa_pairwise = rsn->pairwise_cipher; 157 conf.rsn_pairwise = rsn->pairwise_cipher; 158 conf.wpa_group = rsn->group_cipher; 159 conf.eapol_version = 0; 160 conf.wpa_group_rekey = -1; 161 conf.wpa_group_update_count = 4; 162 conf.wpa_pairwise_update_count = 4; 163 #ifdef CONFIG_IEEE80211W 164 conf.ieee80211w = ieee80211w; 165 if (ieee80211w != NO_MGMT_FRAME_PROTECTION) 166 conf.group_mgmt_cipher = rsn->mgmt_group_cipher; 167 #endif /* CONFIG_IEEE80211W */ 168 169 rsn->auth = wpa_init(addr, &conf, &cb, rsn); 170 if (rsn->auth == NULL) { 171 wpa_printf(MSG_DEBUG, "AUTH: wpa_init() failed"); 172 return -1; 173 } 174 175 /* TODO: support rekeying */ 176 rsn->mgtk_len = wpa_cipher_key_len(conf.wpa_group); 177 if (random_get_bytes(rsn->mgtk, rsn->mgtk_len) < 0) 178 return -1; 179 rsn->mgtk_key_id = 1; 180 181 #ifdef CONFIG_IEEE80211W 182 if (ieee80211w != NO_MGMT_FRAME_PROTECTION) { 183 rsn->igtk_len = wpa_cipher_key_len(conf.group_mgmt_cipher); 184 if (random_get_bytes(rsn->igtk, rsn->igtk_len) < 0) 185 return -1; 186 rsn->igtk_key_id = 4; 187 188 /* group mgmt */ 189 wpa_hexdump_key(MSG_DEBUG, "mesh: Own TX IGTK", 190 rsn->igtk, rsn->igtk_len); 191 wpa_drv_set_key(rsn->wpa_s, 192 wpa_cipher_to_alg(rsn->mgmt_group_cipher), NULL, 193 rsn->igtk_key_id, 1, 194 seq, sizeof(seq), rsn->igtk, rsn->igtk_len); 195 } 196 #endif /* CONFIG_IEEE80211W */ 197 198 /* group privacy / data frames */ 199 wpa_hexdump_key(MSG_DEBUG, "mesh: Own TX MGTK", 200 rsn->mgtk, rsn->mgtk_len); 201 wpa_drv_set_key(rsn->wpa_s, wpa_cipher_to_alg(rsn->group_cipher), NULL, 202 rsn->mgtk_key_id, 1, seq, sizeof(seq), 203 rsn->mgtk, rsn->mgtk_len); 204 205 return 0; 206 } 207 208 209 static void mesh_rsn_deinit(struct mesh_rsn *rsn) 210 { 211 os_memset(rsn->mgtk, 0, sizeof(rsn->mgtk)); 212 rsn->mgtk_len = 0; 213 os_memset(rsn->igtk, 0, sizeof(rsn->igtk)); 214 rsn->igtk_len = 0; 215 if (rsn->auth) 216 wpa_deinit(rsn->auth); 217 } 218 219 220 struct mesh_rsn *mesh_rsn_auth_init(struct wpa_supplicant *wpa_s, 221 struct mesh_conf *conf) 222 { 223 struct mesh_rsn *mesh_rsn; 224 struct hostapd_data *bss = wpa_s->ifmsh->bss[0]; 225 const u8 *ie; 226 size_t ie_len; 227 #ifdef CONFIG_PMKSA_CACHE_EXTERNAL 228 struct external_pmksa_cache *entry; 229 #endif /* CONFIG_PMKSA_CACHE_EXTERNAL */ 230 231 mesh_rsn = os_zalloc(sizeof(*mesh_rsn)); 232 if (mesh_rsn == NULL) 233 return NULL; 234 mesh_rsn->wpa_s = wpa_s; 235 mesh_rsn->pairwise_cipher = conf->pairwise_cipher; 236 mesh_rsn->group_cipher = conf->group_cipher; 237 mesh_rsn->mgmt_group_cipher = conf->mgmt_group_cipher; 238 239 if (__mesh_rsn_auth_init(mesh_rsn, wpa_s->own_addr, 240 conf->ieee80211w) < 0) { 241 mesh_rsn_deinit(mesh_rsn); 242 os_free(mesh_rsn); 243 return NULL; 244 } 245 246 bss->wpa_auth = mesh_rsn->auth; 247 248 #ifdef CONFIG_PMKSA_CACHE_EXTERNAL 249 while ((entry = dl_list_last(&wpa_s->mesh_external_pmksa_cache, 250 struct external_pmksa_cache, 251 list)) != NULL) { 252 int ret; 253 254 ret = wpa_auth_pmksa_add_entry(bss->wpa_auth, 255 entry->pmksa_cache); 256 dl_list_del(&entry->list); 257 os_free(entry); 258 259 if (ret < 0) 260 return NULL; 261 } 262 #endif /* CONFIG_PMKSA_CACHE_EXTERNAL */ 263 264 ie = wpa_auth_get_wpa_ie(mesh_rsn->auth, &ie_len); 265 conf->rsn_ie = (u8 *) ie; 266 conf->rsn_ie_len = ie_len; 267 268 wpa_supplicant_rsn_supp_set_config(wpa_s, wpa_s->current_ssid); 269 270 return mesh_rsn; 271 } 272 273 274 static int index_within_array(const int *array, int idx) 275 { 276 int i; 277 278 for (i = 0; i < idx; i++) { 279 if (array[i] == -1) 280 return 0; 281 } 282 283 return 1; 284 } 285 286 287 static int mesh_rsn_sae_group(struct wpa_supplicant *wpa_s, 288 struct sae_data *sae) 289 { 290 int *groups = wpa_s->ifmsh->bss[0]->conf->sae_groups; 291 292 /* Configuration may have changed, so validate current index */ 293 if (!index_within_array(groups, wpa_s->mesh_rsn->sae_group_index)) 294 return -1; 295 296 for (;;) { 297 int group = groups[wpa_s->mesh_rsn->sae_group_index]; 298 299 if (group <= 0) 300 break; 301 if (sae_set_group(sae, group) == 0) { 302 wpa_dbg(wpa_s, MSG_DEBUG, "SME: Selected SAE group %d", 303 sae->group); 304 return 0; 305 } 306 wpa_s->mesh_rsn->sae_group_index++; 307 } 308 309 return -1; 310 } 311 312 313 static int mesh_rsn_build_sae_commit(struct wpa_supplicant *wpa_s, 314 struct wpa_ssid *ssid, 315 struct sta_info *sta) 316 { 317 if (ssid->passphrase == NULL) { 318 wpa_msg(wpa_s, MSG_DEBUG, "SAE: No password available"); 319 return -1; 320 } 321 322 if (mesh_rsn_sae_group(wpa_s, sta->sae) < 0) { 323 wpa_msg(wpa_s, MSG_DEBUG, "SAE: Failed to select group"); 324 return -1; 325 } 326 327 return sae_prepare_commit(wpa_s->own_addr, sta->addr, 328 (u8 *) ssid->passphrase, 329 os_strlen(ssid->passphrase), sta->sae); 330 } 331 332 333 /* initiate new SAE authentication with sta */ 334 int mesh_rsn_auth_sae_sta(struct wpa_supplicant *wpa_s, 335 struct sta_info *sta) 336 { 337 struct hostapd_data *hapd = wpa_s->ifmsh->bss[0]; 338 struct wpa_ssid *ssid = wpa_s->current_ssid; 339 struct rsn_pmksa_cache_entry *pmksa; 340 unsigned int rnd; 341 int ret; 342 343 if (!ssid) { 344 wpa_msg(wpa_s, MSG_DEBUG, 345 "AUTH: No current_ssid known to initiate new SAE"); 346 return -1; 347 } 348 349 if (!sta->sae) { 350 sta->sae = os_zalloc(sizeof(*sta->sae)); 351 if (sta->sae == NULL) 352 return -1; 353 } 354 355 pmksa = wpa_auth_pmksa_get(hapd->wpa_auth, sta->addr, NULL); 356 if (pmksa) { 357 if (!sta->wpa_sm) 358 sta->wpa_sm = wpa_auth_sta_init(hapd->wpa_auth, 359 sta->addr, NULL); 360 if (!sta->wpa_sm) { 361 wpa_printf(MSG_ERROR, 362 "mesh: Failed to initialize RSN state machine"); 363 return -1; 364 } 365 366 wpa_printf(MSG_DEBUG, 367 "AUTH: Mesh PMKSA cache entry found for " MACSTR 368 " - try to use PMKSA caching instead of new SAE authentication", 369 MAC2STR(sta->addr)); 370 wpa_auth_pmksa_set_to_sm(pmksa, sta->wpa_sm, hapd->wpa_auth, 371 sta->sae->pmkid, sta->sae->pmk); 372 sae_accept_sta(hapd, sta); 373 sta->mesh_sae_pmksa_caching = 1; 374 return 0; 375 } 376 sta->mesh_sae_pmksa_caching = 0; 377 378 if (mesh_rsn_build_sae_commit(wpa_s, ssid, sta)) 379 return -1; 380 381 wpa_msg(wpa_s, MSG_DEBUG, 382 "AUTH: started authentication with SAE peer: " MACSTR, 383 MAC2STR(sta->addr)); 384 385 ret = auth_sae_init_committed(hapd, sta); 386 if (ret) 387 return ret; 388 389 eloop_cancel_timeout(mesh_auth_timer, wpa_s, sta); 390 rnd = rand() % MESH_AUTH_TIMEOUT; 391 eloop_register_timeout(MESH_AUTH_TIMEOUT + rnd, 0, mesh_auth_timer, 392 wpa_s, sta); 393 return 0; 394 } 395 396 397 void mesh_rsn_get_pmkid(struct mesh_rsn *rsn, struct sta_info *sta, u8 *pmkid) 398 { 399 os_memcpy(pmkid, sta->sae->pmkid, SAE_PMKID_LEN); 400 } 401 402 403 static void 404 mesh_rsn_derive_aek(struct mesh_rsn *rsn, struct sta_info *sta) 405 { 406 u8 *myaddr = rsn->wpa_s->own_addr; 407 u8 *peer = sta->addr; 408 u8 *addr1, *addr2; 409 u8 context[RSN_SELECTOR_LEN + 2 * ETH_ALEN], *ptr = context; 410 411 /* 412 * AEK = KDF-Hash-256(PMK, "AEK Derivation", Selected AKM Suite || 413 * min(localMAC, peerMAC) || max(localMAC, peerMAC)) 414 */ 415 /* Selected AKM Suite: SAE */ 416 RSN_SELECTOR_PUT(ptr, RSN_AUTH_KEY_MGMT_SAE); 417 ptr += RSN_SELECTOR_LEN; 418 419 if (os_memcmp(myaddr, peer, ETH_ALEN) < 0) { 420 addr1 = myaddr; 421 addr2 = peer; 422 } else { 423 addr1 = peer; 424 addr2 = myaddr; 425 } 426 os_memcpy(ptr, addr1, ETH_ALEN); 427 ptr += ETH_ALEN; 428 os_memcpy(ptr, addr2, ETH_ALEN); 429 430 sha256_prf(sta->sae->pmk, sizeof(sta->sae->pmk), "AEK Derivation", 431 context, sizeof(context), sta->aek, sizeof(sta->aek)); 432 } 433 434 435 /* derive mesh temporal key from pmk */ 436 int mesh_rsn_derive_mtk(struct wpa_supplicant *wpa_s, struct sta_info *sta) 437 { 438 u8 *ptr; 439 u8 *min, *max; 440 u8 *myaddr = wpa_s->own_addr; 441 u8 *peer = sta->addr; 442 u8 context[2 * WPA_NONCE_LEN + 2 * 2 + RSN_SELECTOR_LEN + 2 * ETH_ALEN]; 443 444 /* 445 * MTK = KDF-Hash-Length(PMK, "Temporal Key Derivation", min(localNonce, 446 * peerNonce) || max(localNonce, peerNonce) || min(localLinkID, 447 * peerLinkID) || max(localLinkID, peerLinkID) || Selected AKM Suite || 448 * min(localMAC, peerMAC) || max(localMAC, peerMAC)) 449 */ 450 ptr = context; 451 if (os_memcmp(sta->my_nonce, sta->peer_nonce, WPA_NONCE_LEN) < 0) { 452 min = sta->my_nonce; 453 max = sta->peer_nonce; 454 } else { 455 min = sta->peer_nonce; 456 max = sta->my_nonce; 457 } 458 os_memcpy(ptr, min, WPA_NONCE_LEN); 459 ptr += WPA_NONCE_LEN; 460 os_memcpy(ptr, max, WPA_NONCE_LEN); 461 ptr += WPA_NONCE_LEN; 462 463 if (sta->my_lid < sta->peer_lid) { 464 WPA_PUT_LE16(ptr, sta->my_lid); 465 ptr += 2; 466 WPA_PUT_LE16(ptr, sta->peer_lid); 467 ptr += 2; 468 } else { 469 WPA_PUT_LE16(ptr, sta->peer_lid); 470 ptr += 2; 471 WPA_PUT_LE16(ptr, sta->my_lid); 472 ptr += 2; 473 } 474 475 /* Selected AKM Suite: SAE */ 476 RSN_SELECTOR_PUT(ptr, RSN_AUTH_KEY_MGMT_SAE); 477 ptr += RSN_SELECTOR_LEN; 478 479 if (os_memcmp(myaddr, peer, ETH_ALEN) < 0) { 480 min = myaddr; 481 max = peer; 482 } else { 483 min = peer; 484 max = myaddr; 485 } 486 os_memcpy(ptr, min, ETH_ALEN); 487 ptr += ETH_ALEN; 488 os_memcpy(ptr, max, ETH_ALEN); 489 490 sta->mtk_len = wpa_cipher_key_len(wpa_s->mesh_rsn->pairwise_cipher); 491 sha256_prf(sta->sae->pmk, SAE_PMK_LEN, 492 "Temporal Key Derivation", context, sizeof(context), 493 sta->mtk, sta->mtk_len); 494 return 0; 495 } 496 497 498 void mesh_rsn_init_ampe_sta(struct wpa_supplicant *wpa_s, struct sta_info *sta) 499 { 500 if (random_get_bytes(sta->my_nonce, WPA_NONCE_LEN) < 0) { 501 wpa_printf(MSG_INFO, "mesh: Failed to derive random nonce"); 502 /* TODO: How to handle this more cleanly? */ 503 } 504 os_memset(sta->peer_nonce, 0, WPA_NONCE_LEN); 505 mesh_rsn_derive_aek(wpa_s->mesh_rsn, sta); 506 } 507 508 509 /* insert AMPE and encrypted MIC at @ie. 510 * @mesh_rsn: mesh RSN context 511 * @sta: STA we're sending to 512 * @cat: pointer to category code in frame header. 513 * @buf: wpabuf to add encrypted AMPE and MIC to. 514 * */ 515 int mesh_rsn_protect_frame(struct mesh_rsn *rsn, struct sta_info *sta, 516 const u8 *cat, struct wpabuf *buf) 517 { 518 struct ieee80211_ampe_ie *ampe; 519 u8 const *ie = wpabuf_head_u8(buf) + wpabuf_len(buf); 520 u8 *ampe_ie, *pos, *mic_payload; 521 const u8 *aad[] = { rsn->wpa_s->own_addr, sta->addr, cat }; 522 const size_t aad_len[] = { ETH_ALEN, ETH_ALEN, ie - cat }; 523 int ret = 0; 524 size_t len; 525 526 len = sizeof(*ampe); 527 if (cat[1] == PLINK_OPEN) 528 len += rsn->mgtk_len + WPA_KEY_RSC_LEN + 4; 529 #ifdef CONFIG_IEEE80211W 530 if (cat[1] == PLINK_OPEN && rsn->igtk_len) 531 len += 2 + 6 + rsn->igtk_len; 532 #endif /* CONFIG_IEEE80211W */ 533 534 if (2 + AES_BLOCK_SIZE + 2 + len > wpabuf_tailroom(buf)) { 535 wpa_printf(MSG_ERROR, "protect frame: buffer too small"); 536 return -EINVAL; 537 } 538 539 ampe_ie = os_zalloc(2 + len); 540 if (!ampe_ie) { 541 wpa_printf(MSG_ERROR, "protect frame: out of memory"); 542 return -ENOMEM; 543 } 544 545 /* IE: AMPE */ 546 ampe_ie[0] = WLAN_EID_AMPE; 547 ampe_ie[1] = len; 548 ampe = (struct ieee80211_ampe_ie *) (ampe_ie + 2); 549 550 RSN_SELECTOR_PUT(ampe->selected_pairwise_suite, 551 RSN_CIPHER_SUITE_CCMP); 552 os_memcpy(ampe->local_nonce, sta->my_nonce, WPA_NONCE_LEN); 553 os_memcpy(ampe->peer_nonce, sta->peer_nonce, WPA_NONCE_LEN); 554 555 pos = (u8 *) (ampe + 1); 556 if (cat[1] != PLINK_OPEN) 557 goto skip_keys; 558 559 /* TODO: Key Replay Counter[8] optionally for 560 * Mesh Group Key Inform/Acknowledge frames */ 561 562 /* TODO: static mgtk for now since we don't support rekeying! */ 563 /* 564 * GTKdata[variable]: 565 * MGTK[variable] || Key RSC[8] || GTKExpirationTime[4] 566 */ 567 os_memcpy(pos, rsn->mgtk, rsn->mgtk_len); 568 pos += rsn->mgtk_len; 569 wpa_drv_get_seqnum(rsn->wpa_s, NULL, rsn->mgtk_key_id, pos); 570 pos += WPA_KEY_RSC_LEN; 571 /* Use fixed GTKExpirationTime for now */ 572 WPA_PUT_LE32(pos, 0xffffffff); 573 pos += 4; 574 575 #ifdef CONFIG_IEEE80211W 576 /* 577 * IGTKdata[variable]: 578 * Key ID[2], IPN[6], IGTK[variable] 579 */ 580 if (rsn->igtk_len) { 581 WPA_PUT_LE16(pos, rsn->igtk_key_id); 582 pos += 2; 583 wpa_drv_get_seqnum(rsn->wpa_s, NULL, rsn->igtk_key_id, pos); 584 pos += 6; 585 os_memcpy(pos, rsn->igtk, rsn->igtk_len); 586 } 587 #endif /* CONFIG_IEEE80211W */ 588 589 skip_keys: 590 wpa_hexdump_key(MSG_DEBUG, "mesh: Plaintext AMPE element", 591 ampe_ie, 2 + len); 592 593 /* IE: MIC */ 594 wpabuf_put_u8(buf, WLAN_EID_MIC); 595 wpabuf_put_u8(buf, AES_BLOCK_SIZE); 596 /* MIC field is output ciphertext */ 597 598 /* encrypt after MIC */ 599 mic_payload = wpabuf_put(buf, 2 + len + AES_BLOCK_SIZE); 600 601 if (aes_siv_encrypt(sta->aek, sizeof(sta->aek), ampe_ie, 2 + len, 3, 602 aad, aad_len, mic_payload)) { 603 wpa_printf(MSG_ERROR, "protect frame: failed to encrypt"); 604 ret = -ENOMEM; 605 } 606 607 os_free(ampe_ie); 608 609 return ret; 610 } 611 612 613 int mesh_rsn_process_ampe(struct wpa_supplicant *wpa_s, struct sta_info *sta, 614 struct ieee802_11_elems *elems, const u8 *cat, 615 const u8 *chosen_pmk, 616 const u8 *start, size_t elems_len) 617 { 618 int ret = 0; 619 struct ieee80211_ampe_ie *ampe; 620 u8 null_nonce[WPA_NONCE_LEN] = {}; 621 u8 ampe_eid; 622 u8 ampe_ie_len; 623 u8 *ampe_buf, *crypt = NULL, *pos, *end; 624 size_t crypt_len; 625 const u8 *aad[] = { sta->addr, wpa_s->own_addr, cat }; 626 const size_t aad_len[] = { ETH_ALEN, ETH_ALEN, 627 (elems->mic - 2) - cat }; 628 size_t key_len; 629 630 if (!sta->sae) { 631 struct hostapd_data *hapd = wpa_s->ifmsh->bss[0]; 632 633 if (!wpa_auth_pmksa_get(hapd->wpa_auth, sta->addr, NULL)) { 634 wpa_printf(MSG_INFO, 635 "Mesh RSN: SAE is not prepared yet"); 636 return -1; 637 } 638 mesh_rsn_auth_sae_sta(wpa_s, sta); 639 } 640 641 if (chosen_pmk && os_memcmp(chosen_pmk, sta->sae->pmkid, PMKID_LEN)) { 642 wpa_msg(wpa_s, MSG_DEBUG, 643 "Mesh RSN: Invalid PMKID (Chosen PMK did not match calculated PMKID)"); 644 return -1; 645 } 646 647 if (!elems->mic || elems->mic_len < AES_BLOCK_SIZE) { 648 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: missing mic ie"); 649 return -1; 650 } 651 652 ampe_buf = (u8 *) elems->mic + elems->mic_len; 653 if ((int) elems_len < ampe_buf - start) 654 return -1; 655 656 crypt_len = elems_len - (elems->mic - start); 657 if (crypt_len < 2 + AES_BLOCK_SIZE) { 658 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: missing ampe ie"); 659 return -1; 660 } 661 662 /* crypt is modified by siv_decrypt */ 663 crypt = os_zalloc(crypt_len); 664 if (!crypt) { 665 wpa_printf(MSG_ERROR, "Mesh RSN: out of memory"); 666 ret = -ENOMEM; 667 goto free; 668 } 669 670 os_memcpy(crypt, elems->mic, crypt_len); 671 672 if (aes_siv_decrypt(sta->aek, sizeof(sta->aek), crypt, crypt_len, 3, 673 aad, aad_len, ampe_buf)) { 674 wpa_printf(MSG_ERROR, "Mesh RSN: frame verification failed!"); 675 ret = -2; 676 goto free; 677 } 678 679 crypt_len -= AES_BLOCK_SIZE; 680 wpa_hexdump_key(MSG_DEBUG, "mesh: Decrypted AMPE element", 681 ampe_buf, crypt_len); 682 683 ampe_eid = *ampe_buf++; 684 ampe_ie_len = *ampe_buf++; 685 686 if (ampe_eid != WLAN_EID_AMPE || 687 (size_t) 2 + ampe_ie_len > crypt_len || 688 ampe_ie_len < sizeof(struct ieee80211_ampe_ie)) { 689 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: invalid ampe ie"); 690 ret = -1; 691 goto free; 692 } 693 694 ampe = (struct ieee80211_ampe_ie *) ampe_buf; 695 pos = (u8 *) (ampe + 1); 696 end = ampe_buf + ampe_ie_len; 697 if (os_memcmp(ampe->peer_nonce, null_nonce, WPA_NONCE_LEN) != 0 && 698 os_memcmp(ampe->peer_nonce, sta->my_nonce, WPA_NONCE_LEN) != 0) { 699 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: invalid peer nonce"); 700 ret = -1; 701 goto free; 702 } 703 os_memcpy(sta->peer_nonce, ampe->local_nonce, 704 sizeof(ampe->local_nonce)); 705 706 /* TODO: Key Replay Counter[8] in Mesh Group Key Inform/Acknowledge 707 * frames */ 708 709 /* 710 * GTKdata shall not be included in Mesh Peering Confirm. While the 711 * standard does not state the same about IGTKdata, that same constraint 712 * needs to apply for it. It makes no sense to include the keys in Mesh 713 * Peering Close frames either, so while the standard does not seem to 714 * have a shall statement for these, they are described without 715 * mentioning GTKdata. 716 * 717 * An earlier implementation used to add GTKdata to both Mesh Peering 718 * Open and Mesh Peering Confirm frames, so ignore the possibly present 719 * GTKdata frame without rejecting the frame as a backwards 720 * compatibility mechanism. 721 */ 722 if (cat[1] != PLINK_OPEN) { 723 if (end > pos) { 724 wpa_hexdump_key(MSG_DEBUG, 725 "mesh: Ignore unexpected GTKdata(etc.) fields in the end of AMPE element in Mesh Peering Confirm/Close", 726 pos, end - pos); 727 } 728 goto free; 729 } 730 731 /* 732 * GTKdata[variable]: 733 * MGTK[variable] || Key RSC[8] || GTKExpirationTime[4] 734 */ 735 sta->mgtk_key_id = 1; /* FIX: Where to get Key ID? */ 736 key_len = wpa_cipher_key_len(wpa_s->mesh_rsn->group_cipher); 737 if ((int) key_len + WPA_KEY_RSC_LEN + 4 > end - pos) { 738 wpa_dbg(wpa_s, MSG_DEBUG, "mesh: Truncated AMPE element"); 739 ret = -1; 740 goto free; 741 } 742 sta->mgtk_len = key_len; 743 os_memcpy(sta->mgtk, pos, sta->mgtk_len); 744 wpa_hexdump_key(MSG_DEBUG, "mesh: GTKdata - MGTK", 745 sta->mgtk, sta->mgtk_len); 746 pos += sta->mgtk_len; 747 wpa_hexdump(MSG_DEBUG, "mesh: GTKdata - MGTK - Key RSC", 748 pos, WPA_KEY_RSC_LEN); 749 os_memcpy(sta->mgtk_rsc, pos, sizeof(sta->mgtk_rsc)); 750 pos += WPA_KEY_RSC_LEN; 751 wpa_printf(MSG_DEBUG, 752 "mesh: GTKdata - MGTK - GTKExpirationTime: %u seconds", 753 WPA_GET_LE32(pos)); 754 pos += 4; 755 756 #ifdef CONFIG_IEEE80211W 757 /* 758 * IGTKdata[variable]: 759 * Key ID[2], IPN[6], IGTK[variable] 760 */ 761 key_len = wpa_cipher_key_len(wpa_s->mesh_rsn->mgmt_group_cipher); 762 if (end - pos >= (int) (2 + 6 + key_len)) { 763 sta->igtk_key_id = WPA_GET_LE16(pos); 764 wpa_printf(MSG_DEBUG, "mesh: IGTKdata - Key ID %u", 765 sta->igtk_key_id); 766 pos += 2; 767 os_memcpy(sta->igtk_rsc, pos, sizeof(sta->igtk_rsc)); 768 wpa_hexdump(MSG_DEBUG, "mesh: IGTKdata - IPN", 769 sta->igtk_rsc, sizeof(sta->igtk_rsc)); 770 pos += 6; 771 os_memcpy(sta->igtk, pos, key_len); 772 sta->igtk_len = key_len; 773 wpa_hexdump_key(MSG_DEBUG, "mesh: IGTKdata - IGTK", 774 sta->igtk, sta->igtk_len); 775 } 776 #endif /* CONFIG_IEEE80211W */ 777 778 free: 779 os_free(crypt); 780 return ret; 781 } 782
