mesh_rsn.c revision 1.1.1.2.10.2
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 struct wpa_auth_callbacks cb; 144 u8 seq[6] = {}; 145 146 wpa_printf(MSG_DEBUG, "AUTH: Initializing group state machine"); 147 148 os_memset(&conf, 0, sizeof(conf)); 149 conf.wpa = WPA_PROTO_RSN; 150 conf.wpa_key_mgmt = WPA_KEY_MGMT_SAE; 151 conf.wpa_pairwise = rsn->pairwise_cipher; 152 conf.rsn_pairwise = rsn->pairwise_cipher; 153 conf.wpa_group = rsn->group_cipher; 154 conf.eapol_version = 0; 155 conf.wpa_group_rekey = -1; 156 #ifdef CONFIG_IEEE80211W 157 conf.ieee80211w = ieee80211w; 158 if (ieee80211w != NO_MGMT_FRAME_PROTECTION) 159 conf.group_mgmt_cipher = rsn->mgmt_group_cipher; 160 #endif /* CONFIG_IEEE80211W */ 161 162 os_memset(&cb, 0, sizeof(cb)); 163 cb.ctx = rsn; 164 cb.logger = auth_logger; 165 cb.get_psk = auth_get_psk; 166 cb.set_key = auth_set_key; 167 cb.start_ampe = auth_start_ampe; 168 169 rsn->auth = wpa_init(addr, &conf, &cb); 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; 227 228 mesh_rsn = os_zalloc(sizeof(*mesh_rsn)); 229 if (mesh_rsn == NULL) 230 return NULL; 231 mesh_rsn->wpa_s = wpa_s; 232 mesh_rsn->pairwise_cipher = conf->pairwise_cipher; 233 mesh_rsn->group_cipher = conf->group_cipher; 234 mesh_rsn->mgmt_group_cipher = conf->mgmt_group_cipher; 235 236 if (__mesh_rsn_auth_init(mesh_rsn, wpa_s->own_addr, 237 conf->ieee80211w) < 0) { 238 mesh_rsn_deinit(mesh_rsn); 239 os_free(mesh_rsn); 240 return NULL; 241 } 242 243 bss->wpa_auth = mesh_rsn->auth; 244 245 ie = wpa_auth_get_wpa_ie(mesh_rsn->auth, &ie_len); 246 conf->rsn_ie = (u8 *) ie; 247 conf->rsn_ie_len = ie_len; 248 249 wpa_supplicant_rsn_supp_set_config(wpa_s, wpa_s->current_ssid); 250 251 return mesh_rsn; 252 } 253 254 255 static int index_within_array(const int *array, int idx) 256 { 257 int i; 258 259 for (i = 0; i < idx; i++) { 260 if (array[i] == -1) 261 return 0; 262 } 263 264 return 1; 265 } 266 267 268 static int mesh_rsn_sae_group(struct wpa_supplicant *wpa_s, 269 struct sae_data *sae) 270 { 271 int *groups = wpa_s->ifmsh->bss[0]->conf->sae_groups; 272 273 /* Configuration may have changed, so validate current index */ 274 if (!index_within_array(groups, wpa_s->mesh_rsn->sae_group_index)) 275 return -1; 276 277 for (;;) { 278 int group = groups[wpa_s->mesh_rsn->sae_group_index]; 279 280 if (group <= 0) 281 break; 282 if (sae_set_group(sae, group) == 0) { 283 wpa_dbg(wpa_s, MSG_DEBUG, "SME: Selected SAE group %d", 284 sae->group); 285 return 0; 286 } 287 wpa_s->mesh_rsn->sae_group_index++; 288 } 289 290 return -1; 291 } 292 293 294 static int mesh_rsn_build_sae_commit(struct wpa_supplicant *wpa_s, 295 struct wpa_ssid *ssid, 296 struct sta_info *sta) 297 { 298 if (ssid->passphrase == NULL) { 299 wpa_msg(wpa_s, MSG_DEBUG, "SAE: No password available"); 300 return -1; 301 } 302 303 if (mesh_rsn_sae_group(wpa_s, sta->sae) < 0) { 304 wpa_msg(wpa_s, MSG_DEBUG, "SAE: Failed to select group"); 305 return -1; 306 } 307 308 return sae_prepare_commit(wpa_s->own_addr, sta->addr, 309 (u8 *) ssid->passphrase, 310 os_strlen(ssid->passphrase), sta->sae); 311 } 312 313 314 /* initiate new SAE authentication with sta */ 315 int mesh_rsn_auth_sae_sta(struct wpa_supplicant *wpa_s, 316 struct sta_info *sta) 317 { 318 struct hostapd_data *hapd = wpa_s->ifmsh->bss[0]; 319 struct wpa_ssid *ssid = wpa_s->current_ssid; 320 struct rsn_pmksa_cache_entry *pmksa; 321 unsigned int rnd; 322 int ret; 323 324 if (!ssid) { 325 wpa_msg(wpa_s, MSG_DEBUG, 326 "AUTH: No current_ssid known to initiate new SAE"); 327 return -1; 328 } 329 330 if (!sta->sae) { 331 sta->sae = os_zalloc(sizeof(*sta->sae)); 332 if (sta->sae == NULL) 333 return -1; 334 } 335 336 pmksa = wpa_auth_pmksa_get(hapd->wpa_auth, sta->addr); 337 if (pmksa) { 338 if (!sta->wpa_sm) 339 sta->wpa_sm = wpa_auth_sta_init(hapd->wpa_auth, 340 sta->addr, NULL); 341 if (!sta->wpa_sm) { 342 wpa_printf(MSG_ERROR, 343 "mesh: Failed to initialize RSN state machine"); 344 return -1; 345 } 346 347 wpa_printf(MSG_DEBUG, 348 "AUTH: Mesh PMKSA cache entry found for " MACSTR 349 " - try to use PMKSA caching instead of new SAE authentication", 350 MAC2STR(sta->addr)); 351 wpa_auth_pmksa_set_to_sm(pmksa, sta->wpa_sm, hapd->wpa_auth, 352 sta->sae->pmkid, sta->sae->pmk); 353 sae_accept_sta(hapd, sta); 354 sta->mesh_sae_pmksa_caching = 1; 355 return 0; 356 } 357 sta->mesh_sae_pmksa_caching = 0; 358 359 if (mesh_rsn_build_sae_commit(wpa_s, ssid, sta)) 360 return -1; 361 362 wpa_msg(wpa_s, MSG_DEBUG, 363 "AUTH: started authentication with SAE peer: " MACSTR, 364 MAC2STR(sta->addr)); 365 366 ret = auth_sae_init_committed(hapd, sta); 367 if (ret) 368 return ret; 369 370 eloop_cancel_timeout(mesh_auth_timer, wpa_s, sta); 371 rnd = rand() % MESH_AUTH_TIMEOUT; 372 eloop_register_timeout(MESH_AUTH_TIMEOUT + rnd, 0, mesh_auth_timer, 373 wpa_s, sta); 374 return 0; 375 } 376 377 378 void mesh_rsn_get_pmkid(struct mesh_rsn *rsn, struct sta_info *sta, u8 *pmkid) 379 { 380 os_memcpy(pmkid, sta->sae->pmkid, SAE_PMKID_LEN); 381 } 382 383 384 static void 385 mesh_rsn_derive_aek(struct mesh_rsn *rsn, struct sta_info *sta) 386 { 387 u8 *myaddr = rsn->wpa_s->own_addr; 388 u8 *peer = sta->addr; 389 u8 *addr1, *addr2; 390 u8 context[RSN_SELECTOR_LEN + 2 * ETH_ALEN], *ptr = context; 391 392 /* 393 * AEK = KDF-Hash-256(PMK, "AEK Derivation", Selected AKM Suite || 394 * min(localMAC, peerMAC) || max(localMAC, peerMAC)) 395 */ 396 /* Selected AKM Suite: SAE */ 397 RSN_SELECTOR_PUT(ptr, RSN_AUTH_KEY_MGMT_SAE); 398 ptr += RSN_SELECTOR_LEN; 399 400 if (os_memcmp(myaddr, peer, ETH_ALEN) < 0) { 401 addr1 = myaddr; 402 addr2 = peer; 403 } else { 404 addr1 = peer; 405 addr2 = myaddr; 406 } 407 os_memcpy(ptr, addr1, ETH_ALEN); 408 ptr += ETH_ALEN; 409 os_memcpy(ptr, addr2, ETH_ALEN); 410 411 sha256_prf(sta->sae->pmk, sizeof(sta->sae->pmk), "AEK Derivation", 412 context, sizeof(context), sta->aek, sizeof(sta->aek)); 413 } 414 415 416 /* derive mesh temporal key from pmk */ 417 int mesh_rsn_derive_mtk(struct wpa_supplicant *wpa_s, struct sta_info *sta) 418 { 419 u8 *ptr; 420 u8 *min, *max; 421 u8 *myaddr = wpa_s->own_addr; 422 u8 *peer = sta->addr; 423 u8 context[2 * WPA_NONCE_LEN + 2 * 2 + RSN_SELECTOR_LEN + 2 * ETH_ALEN]; 424 425 /* 426 * MTK = KDF-Hash-Length(PMK, "Temporal Key Derivation", min(localNonce, 427 * peerNonce) || max(localNonce, peerNonce) || min(localLinkID, 428 * peerLinkID) || max(localLinkID, peerLinkID) || Selected AKM Suite || 429 * min(localMAC, peerMAC) || max(localMAC, peerMAC)) 430 */ 431 ptr = context; 432 if (os_memcmp(sta->my_nonce, sta->peer_nonce, WPA_NONCE_LEN) < 0) { 433 min = sta->my_nonce; 434 max = sta->peer_nonce; 435 } else { 436 min = sta->peer_nonce; 437 max = sta->my_nonce; 438 } 439 os_memcpy(ptr, min, WPA_NONCE_LEN); 440 ptr += WPA_NONCE_LEN; 441 os_memcpy(ptr, max, WPA_NONCE_LEN); 442 ptr += WPA_NONCE_LEN; 443 444 if (sta->my_lid < sta->peer_lid) { 445 WPA_PUT_LE16(ptr, sta->my_lid); 446 ptr += 2; 447 WPA_PUT_LE16(ptr, sta->peer_lid); 448 ptr += 2; 449 } else { 450 WPA_PUT_LE16(ptr, sta->peer_lid); 451 ptr += 2; 452 WPA_PUT_LE16(ptr, sta->my_lid); 453 ptr += 2; 454 } 455 456 /* Selected AKM Suite: SAE */ 457 RSN_SELECTOR_PUT(ptr, RSN_AUTH_KEY_MGMT_SAE); 458 ptr += RSN_SELECTOR_LEN; 459 460 if (os_memcmp(myaddr, peer, ETH_ALEN) < 0) { 461 min = myaddr; 462 max = peer; 463 } else { 464 min = peer; 465 max = myaddr; 466 } 467 os_memcpy(ptr, min, ETH_ALEN); 468 ptr += ETH_ALEN; 469 os_memcpy(ptr, max, ETH_ALEN); 470 471 sta->mtk_len = wpa_cipher_key_len(wpa_s->mesh_rsn->pairwise_cipher); 472 sha256_prf(sta->sae->pmk, SAE_PMK_LEN, 473 "Temporal Key Derivation", context, sizeof(context), 474 sta->mtk, sta->mtk_len); 475 return 0; 476 } 477 478 479 void mesh_rsn_init_ampe_sta(struct wpa_supplicant *wpa_s, struct sta_info *sta) 480 { 481 if (random_get_bytes(sta->my_nonce, WPA_NONCE_LEN) < 0) { 482 wpa_printf(MSG_INFO, "mesh: Failed to derive random nonce"); 483 /* TODO: How to handle this more cleanly? */ 484 } 485 os_memset(sta->peer_nonce, 0, WPA_NONCE_LEN); 486 mesh_rsn_derive_aek(wpa_s->mesh_rsn, sta); 487 } 488 489 490 /* insert AMPE and encrypted MIC at @ie. 491 * @mesh_rsn: mesh RSN context 492 * @sta: STA we're sending to 493 * @cat: pointer to category code in frame header. 494 * @buf: wpabuf to add encrypted AMPE and MIC to. 495 * */ 496 int mesh_rsn_protect_frame(struct mesh_rsn *rsn, struct sta_info *sta, 497 const u8 *cat, struct wpabuf *buf) 498 { 499 struct ieee80211_ampe_ie *ampe; 500 u8 const *ie = wpabuf_head_u8(buf) + wpabuf_len(buf); 501 u8 *ampe_ie, *pos, *mic_payload; 502 const u8 *aad[] = { rsn->wpa_s->own_addr, sta->addr, cat }; 503 const size_t aad_len[] = { ETH_ALEN, ETH_ALEN, ie - cat }; 504 int ret = 0; 505 size_t len; 506 507 len = sizeof(*ampe); 508 if (cat[1] == PLINK_OPEN) 509 len += rsn->mgtk_len + WPA_KEY_RSC_LEN + 4; 510 #ifdef CONFIG_IEEE80211W 511 if (cat[1] == PLINK_OPEN && rsn->igtk_len) 512 len += 2 + 6 + rsn->igtk_len; 513 #endif /* CONFIG_IEEE80211W */ 514 515 if (2 + AES_BLOCK_SIZE + 2 + len > wpabuf_tailroom(buf)) { 516 wpa_printf(MSG_ERROR, "protect frame: buffer too small"); 517 return -EINVAL; 518 } 519 520 ampe_ie = os_zalloc(2 + len); 521 if (!ampe_ie) { 522 wpa_printf(MSG_ERROR, "protect frame: out of memory"); 523 return -ENOMEM; 524 } 525 526 /* IE: AMPE */ 527 ampe_ie[0] = WLAN_EID_AMPE; 528 ampe_ie[1] = len; 529 ampe = (struct ieee80211_ampe_ie *) (ampe_ie + 2); 530 531 RSN_SELECTOR_PUT(ampe->selected_pairwise_suite, 532 RSN_CIPHER_SUITE_CCMP); 533 os_memcpy(ampe->local_nonce, sta->my_nonce, WPA_NONCE_LEN); 534 os_memcpy(ampe->peer_nonce, sta->peer_nonce, WPA_NONCE_LEN); 535 536 pos = (u8 *) (ampe + 1); 537 if (cat[1] != PLINK_OPEN) 538 goto skip_keys; 539 540 /* TODO: Key Replay Counter[8] optionally for 541 * Mesh Group Key Inform/Acknowledge frames */ 542 543 /* TODO: static mgtk for now since we don't support rekeying! */ 544 /* 545 * GTKdata[variable]: 546 * MGTK[variable] || Key RSC[8] || GTKExpirationTime[4] 547 */ 548 os_memcpy(pos, rsn->mgtk, rsn->mgtk_len); 549 pos += rsn->mgtk_len; 550 wpa_drv_get_seqnum(rsn->wpa_s, NULL, rsn->mgtk_key_id, pos); 551 pos += WPA_KEY_RSC_LEN; 552 /* Use fixed GTKExpirationTime for now */ 553 WPA_PUT_LE32(pos, 0xffffffff); 554 pos += 4; 555 556 #ifdef CONFIG_IEEE80211W 557 /* 558 * IGTKdata[variable]: 559 * Key ID[2], IPN[6], IGTK[variable] 560 */ 561 if (rsn->igtk_len) { 562 WPA_PUT_LE16(pos, rsn->igtk_key_id); 563 pos += 2; 564 wpa_drv_get_seqnum(rsn->wpa_s, NULL, rsn->igtk_key_id, pos); 565 pos += 6; 566 os_memcpy(pos, rsn->igtk, rsn->igtk_len); 567 } 568 #endif /* CONFIG_IEEE80211W */ 569 570 skip_keys: 571 wpa_hexdump_key(MSG_DEBUG, "mesh: Plaintext AMPE element", 572 ampe_ie, 2 + len); 573 574 /* IE: MIC */ 575 wpabuf_put_u8(buf, WLAN_EID_MIC); 576 wpabuf_put_u8(buf, AES_BLOCK_SIZE); 577 /* MIC field is output ciphertext */ 578 579 /* encrypt after MIC */ 580 mic_payload = wpabuf_put(buf, 2 + len + AES_BLOCK_SIZE); 581 582 if (aes_siv_encrypt(sta->aek, ampe_ie, 2 + len, 3, 583 aad, aad_len, mic_payload)) { 584 wpa_printf(MSG_ERROR, "protect frame: failed to encrypt"); 585 ret = -ENOMEM; 586 } 587 588 os_free(ampe_ie); 589 590 return ret; 591 } 592 593 594 int mesh_rsn_process_ampe(struct wpa_supplicant *wpa_s, struct sta_info *sta, 595 struct ieee802_11_elems *elems, const u8 *cat, 596 const u8 *chosen_pmk, 597 const u8 *start, size_t elems_len) 598 { 599 int ret = 0; 600 struct ieee80211_ampe_ie *ampe; 601 u8 null_nonce[WPA_NONCE_LEN] = {}; 602 u8 ampe_eid; 603 u8 ampe_ie_len; 604 u8 *ampe_buf, *crypt = NULL, *pos, *end; 605 size_t crypt_len; 606 const u8 *aad[] = { sta->addr, wpa_s->own_addr, cat }; 607 const size_t aad_len[] = { ETH_ALEN, ETH_ALEN, 608 (elems->mic - 2) - cat }; 609 size_t key_len; 610 611 if (!sta->sae) { 612 struct hostapd_data *hapd = wpa_s->ifmsh->bss[0]; 613 614 if (!wpa_auth_pmksa_get(hapd->wpa_auth, sta->addr)) { 615 wpa_printf(MSG_INFO, 616 "Mesh RSN: SAE is not prepared yet"); 617 return -1; 618 } 619 mesh_rsn_auth_sae_sta(wpa_s, sta); 620 } 621 622 if (chosen_pmk && os_memcmp(chosen_pmk, sta->sae->pmkid, PMKID_LEN)) { 623 wpa_msg(wpa_s, MSG_DEBUG, 624 "Mesh RSN: Invalid PMKID (Chosen PMK did not match calculated PMKID)"); 625 return -1; 626 } 627 628 if (!elems->mic || elems->mic_len < AES_BLOCK_SIZE) { 629 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: missing mic ie"); 630 return -1; 631 } 632 633 ampe_buf = (u8 *) elems->mic + elems->mic_len; 634 if ((int) elems_len < ampe_buf - start) 635 return -1; 636 637 crypt_len = elems_len - (elems->mic - start); 638 if (crypt_len < 2 + AES_BLOCK_SIZE) { 639 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: missing ampe ie"); 640 return -1; 641 } 642 643 /* crypt is modified by siv_decrypt */ 644 crypt = os_zalloc(crypt_len); 645 if (!crypt) { 646 wpa_printf(MSG_ERROR, "Mesh RSN: out of memory"); 647 ret = -ENOMEM; 648 goto free; 649 } 650 651 os_memcpy(crypt, elems->mic, crypt_len); 652 653 if (aes_siv_decrypt(sta->aek, crypt, crypt_len, 3, 654 aad, aad_len, ampe_buf)) { 655 wpa_printf(MSG_ERROR, "Mesh RSN: frame verification failed!"); 656 ret = -2; 657 goto free; 658 } 659 660 crypt_len -= AES_BLOCK_SIZE; 661 wpa_hexdump_key(MSG_DEBUG, "mesh: Decrypted AMPE element", 662 ampe_buf, crypt_len); 663 664 ampe_eid = *ampe_buf++; 665 ampe_ie_len = *ampe_buf++; 666 667 if (ampe_eid != WLAN_EID_AMPE || 668 (size_t) 2 + ampe_ie_len > crypt_len || 669 ampe_ie_len < sizeof(struct ieee80211_ampe_ie)) { 670 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: invalid ampe ie"); 671 ret = -1; 672 goto free; 673 } 674 675 ampe = (struct ieee80211_ampe_ie *) ampe_buf; 676 pos = (u8 *) (ampe + 1); 677 end = ampe_buf + ampe_ie_len; 678 if (os_memcmp(ampe->peer_nonce, null_nonce, WPA_NONCE_LEN) != 0 && 679 os_memcmp(ampe->peer_nonce, sta->my_nonce, WPA_NONCE_LEN) != 0) { 680 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: invalid peer nonce"); 681 ret = -1; 682 goto free; 683 } 684 os_memcpy(sta->peer_nonce, ampe->local_nonce, 685 sizeof(ampe->local_nonce)); 686 687 /* TODO: Key Replay Counter[8] in Mesh Group Key Inform/Acknowledge 688 * frames */ 689 690 /* 691 * GTKdata shall not be included in Mesh Peering Confirm. While the 692 * standard does not state the same about IGTKdata, that same constraint 693 * needs to apply for it. It makes no sense to include the keys in Mesh 694 * Peering Close frames either, so while the standard does not seem to 695 * have a shall statement for these, they are described without 696 * mentioning GTKdata. 697 * 698 * An earlier implementation used to add GTKdata to both Mesh Peering 699 * Open and Mesh Peering Confirm frames, so ignore the possibly present 700 * GTKdata frame without rejecting the frame as a backwards 701 * compatibility mechanism. 702 */ 703 if (cat[1] != PLINK_OPEN) { 704 if (end > pos) { 705 wpa_hexdump_key(MSG_DEBUG, 706 "mesh: Ignore unexpected GTKdata(etc.) fields in the end of AMPE element in Mesh Peering Confirm/Close", 707 pos, end - pos); 708 } 709 goto free; 710 } 711 712 /* 713 * GTKdata[variable]: 714 * MGTK[variable] || Key RSC[8] || GTKExpirationTime[4] 715 */ 716 sta->mgtk_key_id = 1; /* FIX: Where to get Key ID? */ 717 key_len = wpa_cipher_key_len(wpa_s->mesh_rsn->group_cipher); 718 if ((int) key_len + WPA_KEY_RSC_LEN + 4 > end - pos) { 719 wpa_dbg(wpa_s, MSG_DEBUG, "mesh: Truncated AMPE element"); 720 ret = -1; 721 goto free; 722 } 723 sta->mgtk_len = key_len; 724 os_memcpy(sta->mgtk, pos, sta->mgtk_len); 725 wpa_hexdump_key(MSG_DEBUG, "mesh: GTKdata - MGTK", 726 sta->mgtk, sta->mgtk_len); 727 pos += sta->mgtk_len; 728 wpa_hexdump(MSG_DEBUG, "mesh: GTKdata - MGTK - Key RSC", 729 pos, WPA_KEY_RSC_LEN); 730 os_memcpy(sta->mgtk_rsc, pos, sizeof(sta->mgtk_rsc)); 731 pos += WPA_KEY_RSC_LEN; 732 wpa_printf(MSG_DEBUG, 733 "mesh: GTKdata - MGTK - GTKExpirationTime: %u seconds", 734 WPA_GET_LE32(pos)); 735 pos += 4; 736 737 #ifdef CONFIG_IEEE80211W 738 /* 739 * IGTKdata[variable]: 740 * Key ID[2], IPN[6], IGTK[variable] 741 */ 742 key_len = wpa_cipher_key_len(wpa_s->mesh_rsn->mgmt_group_cipher); 743 if (end - pos >= (int) (2 + 6 + key_len)) { 744 sta->igtk_key_id = WPA_GET_LE16(pos); 745 wpa_printf(MSG_DEBUG, "mesh: IGTKdata - Key ID %u", 746 sta->igtk_key_id); 747 pos += 2; 748 os_memcpy(sta->igtk_rsc, pos, sizeof(sta->igtk_rsc)); 749 wpa_hexdump(MSG_DEBUG, "mesh: IGTKdata - IPN", 750 sta->igtk_rsc, sizeof(sta->igtk_rsc)); 751 pos += 6; 752 os_memcpy(sta->igtk, pos, key_len); 753 sta->igtk_len = key_len; 754 wpa_hexdump_key(MSG_DEBUG, "mesh: IGTKdata - IGTK", 755 sta->igtk, sta->igtk_len); 756 } 757 #endif /* CONFIG_IEEE80211W */ 758 759 free: 760 os_free(crypt); 761 return ret; 762 } 763
Indexes created Sun Mar 29 00:23:15 UTC 2026