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 size_t *psk_len, int *vlan_id) 80 { 81 struct mesh_rsn *mesh_rsn = ctx; 82 struct hostapd_data *hapd = mesh_rsn->wpa_s->ifmsh->bss[0]; 83 struct sta_info *sta = ap_get_sta(hapd, addr); 84 85 if (psk_len) 86 *psk_len = PMK_LEN; 87 if (vlan_id) 88 *vlan_id = 0; 89 wpa_printf(MSG_DEBUG, "AUTH: %s (addr=" MACSTR " prev_psk=%p)", 90 __func__, MAC2STR(addr), prev_psk); 91 92 if (sta && sta->auth_alg == WLAN_AUTH_SAE) { 93 if (!sta->sae || prev_psk) 94 return NULL; 95 return sta->sae->pmk; 96 } 97 98 return NULL; 99 } 100 101 102 static int auth_set_key(void *ctx, int vlan_id, enum wpa_alg alg, 103 const u8 *addr, int idx, u8 *key, size_t key_len) 104 { 105 struct mesh_rsn *mesh_rsn = ctx; 106 u8 seq[6]; 107 108 os_memset(seq, 0, sizeof(seq)); 109 110 if (addr) { 111 wpa_printf(MSG_DEBUG, "AUTH: %s(alg=%d addr=" MACSTR 112 " key_idx=%d)", 113 __func__, alg, MAC2STR(addr), idx); 114 } else { 115 wpa_printf(MSG_DEBUG, "AUTH: %s(alg=%d key_idx=%d)", 116 __func__, alg, idx); 117 } 118 wpa_hexdump_key(MSG_DEBUG, "AUTH: set_key - key", key, key_len); 119 120 return wpa_drv_set_key(mesh_rsn->wpa_s, alg, addr, idx, 121 1, seq, 6, key, key_len); 122 } 123 124 125 static int auth_start_ampe(void *ctx, const u8 *addr) 126 { 127 struct mesh_rsn *mesh_rsn = ctx; 128 struct hostapd_data *hapd; 129 struct sta_info *sta; 130 131 if (mesh_rsn->wpa_s->current_ssid->mode != WPAS_MODE_MESH) 132 return -1; 133 134 hapd = mesh_rsn->wpa_s->ifmsh->bss[0]; 135 sta = ap_get_sta(hapd, addr); 136 if (sta) 137 eloop_cancel_timeout(mesh_auth_timer, mesh_rsn->wpa_s, sta); 138 139 mesh_mpm_auth_peer(mesh_rsn->wpa_s, addr); 140 return 0; 141 } 142 143 144 static int __mesh_rsn_auth_init(struct mesh_rsn *rsn, const u8 *addr, 145 enum mfp_options ieee80211w, int ocv) 146 { 147 struct wpa_auth_config conf; 148 static const struct wpa_auth_callbacks cb = { 149 .logger = auth_logger, 150 .get_psk = auth_get_psk, 151 .set_key = auth_set_key, 152 .start_ampe = auth_start_ampe, 153 }; 154 u8 seq[6] = {}; 155 156 wpa_printf(MSG_DEBUG, "AUTH: Initializing group state machine"); 157 158 os_memset(&conf, 0, sizeof(conf)); 159 conf.wpa = WPA_PROTO_RSN; 160 conf.wpa_key_mgmt = WPA_KEY_MGMT_SAE; 161 conf.wpa_pairwise = rsn->pairwise_cipher; 162 conf.rsn_pairwise = rsn->pairwise_cipher; 163 conf.wpa_group = rsn->group_cipher; 164 conf.eapol_version = 0; 165 conf.wpa_group_rekey = -1; 166 conf.wpa_group_update_count = 4; 167 conf.wpa_pairwise_update_count = 4; 168 #ifdef CONFIG_IEEE80211W 169 conf.ieee80211w = ieee80211w; 170 if (ieee80211w != NO_MGMT_FRAME_PROTECTION) 171 conf.group_mgmt_cipher = rsn->mgmt_group_cipher; 172 #endif /* CONFIG_IEEE80211W */ 173 #ifdef CONFIG_OCV 174 conf.ocv = ocv; 175 #endif /* CONFIG_OCV */ 176 177 rsn->auth = wpa_init(addr, &conf, &cb, rsn); 178 if (rsn->auth == NULL) { 179 wpa_printf(MSG_DEBUG, "AUTH: wpa_init() failed"); 180 return -1; 181 } 182 183 /* TODO: support rekeying */ 184 rsn->mgtk_len = wpa_cipher_key_len(conf.wpa_group); 185 if (random_get_bytes(rsn->mgtk, rsn->mgtk_len) < 0) 186 return -1; 187 rsn->mgtk_key_id = 1; 188 189 #ifdef CONFIG_IEEE80211W 190 if (ieee80211w != NO_MGMT_FRAME_PROTECTION) { 191 rsn->igtk_len = wpa_cipher_key_len(conf.group_mgmt_cipher); 192 if (random_get_bytes(rsn->igtk, rsn->igtk_len) < 0) 193 return -1; 194 rsn->igtk_key_id = 4; 195 196 /* group mgmt */ 197 wpa_hexdump_key(MSG_DEBUG, "mesh: Own TX IGTK", 198 rsn->igtk, rsn->igtk_len); 199 wpa_drv_set_key(rsn->wpa_s, 200 wpa_cipher_to_alg(rsn->mgmt_group_cipher), NULL, 201 rsn->igtk_key_id, 1, 202 seq, sizeof(seq), rsn->igtk, rsn->igtk_len); 203 } 204 #endif /* CONFIG_IEEE80211W */ 205 206 /* group privacy / data frames */ 207 wpa_hexdump_key(MSG_DEBUG, "mesh: Own TX MGTK", 208 rsn->mgtk, rsn->mgtk_len); 209 wpa_drv_set_key(rsn->wpa_s, wpa_cipher_to_alg(rsn->group_cipher), NULL, 210 rsn->mgtk_key_id, 1, seq, sizeof(seq), 211 rsn->mgtk, rsn->mgtk_len); 212 213 return 0; 214 } 215 216 217 static void mesh_rsn_deinit(struct mesh_rsn *rsn) 218 { 219 os_memset(rsn->mgtk, 0, sizeof(rsn->mgtk)); 220 rsn->mgtk_len = 0; 221 os_memset(rsn->igtk, 0, sizeof(rsn->igtk)); 222 rsn->igtk_len = 0; 223 if (rsn->auth) 224 wpa_deinit(rsn->auth); 225 } 226 227 228 struct mesh_rsn *mesh_rsn_auth_init(struct wpa_supplicant *wpa_s, 229 struct mesh_conf *conf) 230 { 231 struct mesh_rsn *mesh_rsn; 232 struct hostapd_data *bss = wpa_s->ifmsh->bss[0]; 233 const u8 *ie; 234 size_t ie_len; 235 #ifdef CONFIG_PMKSA_CACHE_EXTERNAL 236 struct external_pmksa_cache *entry; 237 #endif /* CONFIG_PMKSA_CACHE_EXTERNAL */ 238 239 mesh_rsn = os_zalloc(sizeof(*mesh_rsn)); 240 if (mesh_rsn == NULL) 241 return NULL; 242 mesh_rsn->wpa_s = wpa_s; 243 mesh_rsn->pairwise_cipher = conf->pairwise_cipher; 244 mesh_rsn->group_cipher = conf->group_cipher; 245 mesh_rsn->mgmt_group_cipher = conf->mgmt_group_cipher; 246 247 if (__mesh_rsn_auth_init(mesh_rsn, wpa_s->own_addr, 248 conf->ieee80211w, conf->ocv) < 0) { 249 mesh_rsn_deinit(mesh_rsn); 250 os_free(mesh_rsn); 251 return NULL; 252 } 253 254 bss->wpa_auth = mesh_rsn->auth; 255 256 #ifdef CONFIG_PMKSA_CACHE_EXTERNAL 257 while ((entry = dl_list_last(&wpa_s->mesh_external_pmksa_cache, 258 struct external_pmksa_cache, 259 list)) != NULL) { 260 int ret; 261 262 ret = wpa_auth_pmksa_add_entry(bss->wpa_auth, 263 entry->pmksa_cache); 264 dl_list_del(&entry->list); 265 os_free(entry); 266 267 if (ret < 0) 268 return NULL; 269 } 270 #endif /* CONFIG_PMKSA_CACHE_EXTERNAL */ 271 272 ie = wpa_auth_get_wpa_ie(mesh_rsn->auth, &ie_len); 273 conf->rsn_ie = (u8 *) ie; 274 conf->rsn_ie_len = ie_len; 275 276 wpa_supplicant_rsn_supp_set_config(wpa_s, wpa_s->current_ssid); 277 278 return mesh_rsn; 279 } 280 281 282 static int index_within_array(const int *array, int idx) 283 { 284 int i; 285 286 for (i = 0; i < idx; i++) { 287 if (array[i] == -1) 288 return 0; 289 } 290 291 return 1; 292 } 293 294 295 static int mesh_rsn_sae_group(struct wpa_supplicant *wpa_s, 296 struct sae_data *sae) 297 { 298 int *groups = wpa_s->ifmsh->bss[0]->conf->sae_groups; 299 300 /* Configuration may have changed, so validate current index */ 301 if (!index_within_array(groups, wpa_s->mesh_rsn->sae_group_index)) 302 return -1; 303 304 for (;;) { 305 int group = groups[wpa_s->mesh_rsn->sae_group_index]; 306 307 if (group <= 0) 308 break; 309 if (sae_set_group(sae, group) == 0) { 310 wpa_dbg(wpa_s, MSG_DEBUG, "SME: Selected SAE group %d", 311 sae->group); 312 return 0; 313 } 314 wpa_s->mesh_rsn->sae_group_index++; 315 } 316 317 return -1; 318 } 319 320 321 static int mesh_rsn_build_sae_commit(struct wpa_supplicant *wpa_s, 322 struct wpa_ssid *ssid, 323 struct sta_info *sta) 324 { 325 const char *password; 326 327 password = ssid->sae_password; 328 if (!password) 329 password = ssid->passphrase; 330 if (!password) { 331 wpa_msg(wpa_s, MSG_DEBUG, "SAE: No password available"); 332 return -1; 333 } 334 335 if (mesh_rsn_sae_group(wpa_s, sta->sae) < 0) { 336 wpa_msg(wpa_s, MSG_DEBUG, "SAE: Failed to select group"); 337 return -1; 338 } 339 340 if (sta->sae->tmp && !sta->sae->tmp->pw_id && ssid->sae_password_id) { 341 sta->sae->tmp->pw_id = os_strdup(ssid->sae_password_id); 342 if (!sta->sae->tmp->pw_id) 343 return -1; 344 } 345 return sae_prepare_commit(wpa_s->own_addr, sta->addr, 346 (u8 *) password, os_strlen(password), 347 ssid->sae_password_id, 348 sta->sae); 349 } 350 351 352 /* initiate new SAE authentication with sta */ 353 int mesh_rsn_auth_sae_sta(struct wpa_supplicant *wpa_s, 354 struct sta_info *sta) 355 { 356 struct hostapd_data *hapd = wpa_s->ifmsh->bss[0]; 357 struct wpa_ssid *ssid = wpa_s->current_ssid; 358 struct rsn_pmksa_cache_entry *pmksa; 359 unsigned int rnd; 360 int ret; 361 362 if (!ssid) { 363 wpa_msg(wpa_s, MSG_DEBUG, 364 "AUTH: No current_ssid known to initiate new SAE"); 365 return -1; 366 } 367 368 if (!sta->sae) { 369 sta->sae = os_zalloc(sizeof(*sta->sae)); 370 if (sta->sae == NULL) 371 return -1; 372 } 373 374 pmksa = wpa_auth_pmksa_get(hapd->wpa_auth, sta->addr, NULL); 375 if (pmksa) { 376 if (!sta->wpa_sm) 377 sta->wpa_sm = wpa_auth_sta_init(hapd->wpa_auth, 378 sta->addr, NULL); 379 if (!sta->wpa_sm) { 380 wpa_printf(MSG_ERROR, 381 "mesh: Failed to initialize RSN state machine"); 382 return -1; 383 } 384 385 wpa_printf(MSG_DEBUG, 386 "AUTH: Mesh PMKSA cache entry found for " MACSTR 387 " - try to use PMKSA caching instead of new SAE authentication", 388 MAC2STR(sta->addr)); 389 wpa_auth_pmksa_set_to_sm(pmksa, sta->wpa_sm, hapd->wpa_auth, 390 sta->sae->pmkid, sta->sae->pmk); 391 sae_accept_sta(hapd, sta); 392 sta->mesh_sae_pmksa_caching = 1; 393 return 0; 394 } 395 sta->mesh_sae_pmksa_caching = 0; 396 397 if (mesh_rsn_build_sae_commit(wpa_s, ssid, sta)) 398 return -1; 399 400 wpa_msg(wpa_s, MSG_DEBUG, 401 "AUTH: started authentication with SAE peer: " MACSTR, 402 MAC2STR(sta->addr)); 403 404 ret = auth_sae_init_committed(hapd, sta); 405 if (ret) 406 return ret; 407 408 eloop_cancel_timeout(mesh_auth_timer, wpa_s, sta); 409 rnd = rand() % MESH_AUTH_TIMEOUT; 410 eloop_register_timeout(MESH_AUTH_TIMEOUT + rnd, 0, mesh_auth_timer, 411 wpa_s, sta); 412 return 0; 413 } 414 415 416 void mesh_rsn_get_pmkid(struct mesh_rsn *rsn, struct sta_info *sta, u8 *pmkid) 417 { 418 os_memcpy(pmkid, sta->sae->pmkid, SAE_PMKID_LEN); 419 } 420 421 422 static void 423 mesh_rsn_derive_aek(struct mesh_rsn *rsn, struct sta_info *sta) 424 { 425 u8 *myaddr = rsn->wpa_s->own_addr; 426 u8 *peer = sta->addr; 427 u8 *addr1, *addr2; 428 u8 context[RSN_SELECTOR_LEN + 2 * ETH_ALEN], *ptr = context; 429 430 /* 431 * AEK = KDF-Hash-256(PMK, "AEK Derivation", Selected AKM Suite || 432 * min(localMAC, peerMAC) || max(localMAC, peerMAC)) 433 */ 434 /* Selected AKM Suite: SAE */ 435 RSN_SELECTOR_PUT(ptr, RSN_AUTH_KEY_MGMT_SAE); 436 ptr += RSN_SELECTOR_LEN; 437 438 if (os_memcmp(myaddr, peer, ETH_ALEN) < 0) { 439 addr1 = myaddr; 440 addr2 = peer; 441 } else { 442 addr1 = peer; 443 addr2 = myaddr; 444 } 445 os_memcpy(ptr, addr1, ETH_ALEN); 446 ptr += ETH_ALEN; 447 os_memcpy(ptr, addr2, ETH_ALEN); 448 449 sha256_prf(sta->sae->pmk, sizeof(sta->sae->pmk), "AEK Derivation", 450 context, sizeof(context), sta->aek, sizeof(sta->aek)); 451 } 452 453 454 /* derive mesh temporal key from pmk */ 455 int mesh_rsn_derive_mtk(struct wpa_supplicant *wpa_s, struct sta_info *sta) 456 { 457 u8 *ptr; 458 u8 *min, *max; 459 u8 *myaddr = wpa_s->own_addr; 460 u8 *peer = sta->addr; 461 u8 context[2 * WPA_NONCE_LEN + 2 * 2 + RSN_SELECTOR_LEN + 2 * ETH_ALEN]; 462 463 /* 464 * MTK = KDF-Hash-Length(PMK, "Temporal Key Derivation", min(localNonce, 465 * peerNonce) || max(localNonce, peerNonce) || min(localLinkID, 466 * peerLinkID) || max(localLinkID, peerLinkID) || Selected AKM Suite || 467 * min(localMAC, peerMAC) || max(localMAC, peerMAC)) 468 */ 469 ptr = context; 470 if (os_memcmp(sta->my_nonce, sta->peer_nonce, WPA_NONCE_LEN) < 0) { 471 min = sta->my_nonce; 472 max = sta->peer_nonce; 473 } else { 474 min = sta->peer_nonce; 475 max = sta->my_nonce; 476 } 477 os_memcpy(ptr, min, WPA_NONCE_LEN); 478 ptr += WPA_NONCE_LEN; 479 os_memcpy(ptr, max, WPA_NONCE_LEN); 480 ptr += WPA_NONCE_LEN; 481 482 if (sta->my_lid < sta->peer_lid) { 483 WPA_PUT_LE16(ptr, sta->my_lid); 484 ptr += 2; 485 WPA_PUT_LE16(ptr, sta->peer_lid); 486 ptr += 2; 487 } else { 488 WPA_PUT_LE16(ptr, sta->peer_lid); 489 ptr += 2; 490 WPA_PUT_LE16(ptr, sta->my_lid); 491 ptr += 2; 492 } 493 494 /* Selected AKM Suite: SAE */ 495 RSN_SELECTOR_PUT(ptr, RSN_AUTH_KEY_MGMT_SAE); 496 ptr += RSN_SELECTOR_LEN; 497 498 if (os_memcmp(myaddr, peer, ETH_ALEN) < 0) { 499 min = myaddr; 500 max = peer; 501 } else { 502 min = peer; 503 max = myaddr; 504 } 505 os_memcpy(ptr, min, ETH_ALEN); 506 ptr += ETH_ALEN; 507 os_memcpy(ptr, max, ETH_ALEN); 508 509 sta->mtk_len = wpa_cipher_key_len(wpa_s->mesh_rsn->pairwise_cipher); 510 sha256_prf(sta->sae->pmk, SAE_PMK_LEN, 511 "Temporal Key Derivation", context, sizeof(context), 512 sta->mtk, sta->mtk_len); 513 return 0; 514 } 515 516 517 void mesh_rsn_init_ampe_sta(struct wpa_supplicant *wpa_s, struct sta_info *sta) 518 { 519 if (random_get_bytes(sta->my_nonce, WPA_NONCE_LEN) < 0) { 520 wpa_printf(MSG_INFO, "mesh: Failed to derive random nonce"); 521 /* TODO: How to handle this more cleanly? */ 522 } 523 os_memset(sta->peer_nonce, 0, WPA_NONCE_LEN); 524 mesh_rsn_derive_aek(wpa_s->mesh_rsn, sta); 525 } 526 527 528 /* insert AMPE and encrypted MIC at @ie. 529 * @mesh_rsn: mesh RSN context 530 * @sta: STA we're sending to 531 * @cat: pointer to category code in frame header. 532 * @buf: wpabuf to add encrypted AMPE and MIC to. 533 * */ 534 int mesh_rsn_protect_frame(struct mesh_rsn *rsn, struct sta_info *sta, 535 const u8 *cat, struct wpabuf *buf) 536 { 537 struct ieee80211_ampe_ie *ampe; 538 u8 const *ie = wpabuf_head_u8(buf) + wpabuf_len(buf); 539 u8 *ampe_ie, *pos, *mic_payload; 540 const u8 *aad[] = { rsn->wpa_s->own_addr, sta->addr, cat }; 541 const size_t aad_len[] = { ETH_ALEN, ETH_ALEN, ie - cat }; 542 int ret = 0; 543 size_t len; 544 545 len = sizeof(*ampe); 546 if (cat[1] == PLINK_OPEN) 547 len += rsn->mgtk_len + WPA_KEY_RSC_LEN + 4; 548 #ifdef CONFIG_IEEE80211W 549 if (cat[1] == PLINK_OPEN && rsn->igtk_len) 550 len += 2 + 6 + rsn->igtk_len; 551 #endif /* CONFIG_IEEE80211W */ 552 553 if (2 + AES_BLOCK_SIZE + 2 + len > wpabuf_tailroom(buf)) { 554 wpa_printf(MSG_ERROR, "protect frame: buffer too small"); 555 return -EINVAL; 556 } 557 558 ampe_ie = os_zalloc(2 + len); 559 if (!ampe_ie) { 560 wpa_printf(MSG_ERROR, "protect frame: out of memory"); 561 return -ENOMEM; 562 } 563 564 /* IE: AMPE */ 565 ampe_ie[0] = WLAN_EID_AMPE; 566 ampe_ie[1] = len; 567 ampe = (struct ieee80211_ampe_ie *) (ampe_ie + 2); 568 569 RSN_SELECTOR_PUT(ampe->selected_pairwise_suite, 570 RSN_CIPHER_SUITE_CCMP); 571 os_memcpy(ampe->local_nonce, sta->my_nonce, WPA_NONCE_LEN); 572 os_memcpy(ampe->peer_nonce, sta->peer_nonce, WPA_NONCE_LEN); 573 574 pos = (u8 *) (ampe + 1); 575 if (cat[1] != PLINK_OPEN) 576 goto skip_keys; 577 578 /* TODO: Key Replay Counter[8] optionally for 579 * Mesh Group Key Inform/Acknowledge frames */ 580 581 /* TODO: static mgtk for now since we don't support rekeying! */ 582 /* 583 * GTKdata[variable]: 584 * MGTK[variable] || Key RSC[8] || GTKExpirationTime[4] 585 */ 586 os_memcpy(pos, rsn->mgtk, rsn->mgtk_len); 587 pos += rsn->mgtk_len; 588 wpa_drv_get_seqnum(rsn->wpa_s, NULL, rsn->mgtk_key_id, pos); 589 pos += WPA_KEY_RSC_LEN; 590 /* Use fixed GTKExpirationTime for now */ 591 WPA_PUT_LE32(pos, 0xffffffff); 592 pos += 4; 593 594 #ifdef CONFIG_IEEE80211W 595 /* 596 * IGTKdata[variable]: 597 * Key ID[2], IPN[6], IGTK[variable] 598 */ 599 if (rsn->igtk_len) { 600 WPA_PUT_LE16(pos, rsn->igtk_key_id); 601 pos += 2; 602 wpa_drv_get_seqnum(rsn->wpa_s, NULL, rsn->igtk_key_id, pos); 603 pos += 6; 604 os_memcpy(pos, rsn->igtk, rsn->igtk_len); 605 } 606 #endif /* CONFIG_IEEE80211W */ 607 608 skip_keys: 609 wpa_hexdump_key(MSG_DEBUG, "mesh: Plaintext AMPE element", 610 ampe_ie, 2 + len); 611 612 /* IE: MIC */ 613 wpabuf_put_u8(buf, WLAN_EID_MIC); 614 wpabuf_put_u8(buf, AES_BLOCK_SIZE); 615 /* MIC field is output ciphertext */ 616 617 /* encrypt after MIC */ 618 mic_payload = wpabuf_put(buf, 2 + len + AES_BLOCK_SIZE); 619 620 if (aes_siv_encrypt(sta->aek, sizeof(sta->aek), ampe_ie, 2 + len, 3, 621 aad, aad_len, mic_payload)) { 622 wpa_printf(MSG_ERROR, "protect frame: failed to encrypt"); 623 ret = -ENOMEM; 624 } 625 626 os_free(ampe_ie); 627 628 return ret; 629 } 630 631 632 int mesh_rsn_process_ampe(struct wpa_supplicant *wpa_s, struct sta_info *sta, 633 struct ieee802_11_elems *elems, const u8 *cat, 634 const u8 *chosen_pmk, 635 const u8 *start, size_t elems_len) 636 { 637 int ret = 0; 638 struct ieee80211_ampe_ie *ampe; 639 u8 null_nonce[WPA_NONCE_LEN] = {}; 640 u8 ampe_eid; 641 u8 ampe_ie_len; 642 u8 *ampe_buf, *crypt = NULL, *pos, *end; 643 size_t crypt_len; 644 const u8 *aad[] = { sta->addr, wpa_s->own_addr, cat }; 645 const size_t aad_len[] = { ETH_ALEN, ETH_ALEN, 646 elems->mic ? (elems->mic - 2) - cat : 0 }; 647 size_t key_len; 648 649 if (!sta->sae) { 650 struct hostapd_data *hapd = wpa_s->ifmsh->bss[0]; 651 652 if (!wpa_auth_pmksa_get(hapd->wpa_auth, sta->addr, NULL)) { 653 wpa_printf(MSG_INFO, 654 "Mesh RSN: SAE is not prepared yet"); 655 return -1; 656 } 657 mesh_rsn_auth_sae_sta(wpa_s, sta); 658 } 659 660 if (chosen_pmk && 661 (!sta->sae || 662 os_memcmp(chosen_pmk, sta->sae->pmkid, PMKID_LEN) != 0)) { 663 wpa_msg(wpa_s, MSG_DEBUG, 664 "Mesh RSN: Invalid PMKID (Chosen PMK did not match calculated PMKID)"); 665 return -1; 666 } 667 668 if (!elems->mic || elems->mic_len < AES_BLOCK_SIZE) { 669 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: missing mic ie"); 670 return -1; 671 } 672 673 ampe_buf = (u8 *) elems->mic + elems->mic_len; 674 if ((int) elems_len < ampe_buf - start) 675 return -1; 676 677 crypt_len = elems_len - (elems->mic - start); 678 if (crypt_len < 2 + AES_BLOCK_SIZE) { 679 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: missing ampe ie"); 680 return -1; 681 } 682 683 /* crypt is modified by siv_decrypt */ 684 crypt = os_zalloc(crypt_len); 685 if (!crypt) { 686 wpa_printf(MSG_ERROR, "Mesh RSN: out of memory"); 687 ret = -ENOMEM; 688 goto free; 689 } 690 691 os_memcpy(crypt, elems->mic, crypt_len); 692 693 if (aes_siv_decrypt(sta->aek, sizeof(sta->aek), crypt, crypt_len, 3, 694 aad, aad_len, ampe_buf)) { 695 wpa_printf(MSG_ERROR, "Mesh RSN: frame verification failed!"); 696 ret = -2; 697 goto free; 698 } 699 700 crypt_len -= AES_BLOCK_SIZE; 701 wpa_hexdump_key(MSG_DEBUG, "mesh: Decrypted AMPE element", 702 ampe_buf, crypt_len); 703 704 ampe_eid = *ampe_buf++; 705 ampe_ie_len = *ampe_buf++; 706 707 if (ampe_eid != WLAN_EID_AMPE || 708 (size_t) 2 + ampe_ie_len > crypt_len || 709 ampe_ie_len < sizeof(struct ieee80211_ampe_ie)) { 710 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: invalid ampe ie"); 711 ret = -1; 712 goto free; 713 } 714 715 ampe = (struct ieee80211_ampe_ie *) ampe_buf; 716 pos = (u8 *) (ampe + 1); 717 end = ampe_buf + ampe_ie_len; 718 if (os_memcmp(ampe->peer_nonce, null_nonce, WPA_NONCE_LEN) != 0 && 719 os_memcmp(ampe->peer_nonce, sta->my_nonce, WPA_NONCE_LEN) != 0) { 720 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: invalid peer nonce"); 721 ret = -1; 722 goto free; 723 } 724 os_memcpy(sta->peer_nonce, ampe->local_nonce, 725 sizeof(ampe->local_nonce)); 726 727 /* TODO: Key Replay Counter[8] in Mesh Group Key Inform/Acknowledge 728 * frames */ 729 730 /* 731 * GTKdata shall not be included in Mesh Peering Confirm. While the 732 * standard does not state the same about IGTKdata, that same constraint 733 * needs to apply for it. It makes no sense to include the keys in Mesh 734 * Peering Close frames either, so while the standard does not seem to 735 * have a shall statement for these, they are described without 736 * mentioning GTKdata. 737 * 738 * An earlier implementation used to add GTKdata to both Mesh Peering 739 * Open and Mesh Peering Confirm frames, so ignore the possibly present 740 * GTKdata frame without rejecting the frame as a backwards 741 * compatibility mechanism. 742 */ 743 if (cat[1] != PLINK_OPEN) { 744 if (end > pos) { 745 wpa_hexdump_key(MSG_DEBUG, 746 "mesh: Ignore unexpected GTKdata(etc.) fields in the end of AMPE element in Mesh Peering Confirm/Close", 747 pos, end - pos); 748 } 749 goto free; 750 } 751 752 /* 753 * GTKdata[variable]: 754 * MGTK[variable] || Key RSC[8] || GTKExpirationTime[4] 755 */ 756 sta->mgtk_key_id = 1; /* FIX: Where to get Key ID? */ 757 key_len = wpa_cipher_key_len(wpa_s->mesh_rsn->group_cipher); 758 if ((int) key_len + WPA_KEY_RSC_LEN + 4 > end - pos) { 759 wpa_dbg(wpa_s, MSG_DEBUG, "mesh: Truncated AMPE element"); 760 ret = -1; 761 goto free; 762 } 763 sta->mgtk_len = key_len; 764 os_memcpy(sta->mgtk, pos, sta->mgtk_len); 765 wpa_hexdump_key(MSG_DEBUG, "mesh: GTKdata - MGTK", 766 sta->mgtk, sta->mgtk_len); 767 pos += sta->mgtk_len; 768 wpa_hexdump(MSG_DEBUG, "mesh: GTKdata - MGTK - Key RSC", 769 pos, WPA_KEY_RSC_LEN); 770 os_memcpy(sta->mgtk_rsc, pos, sizeof(sta->mgtk_rsc)); 771 pos += WPA_KEY_RSC_LEN; 772 wpa_printf(MSG_DEBUG, 773 "mesh: GTKdata - MGTK - GTKExpirationTime: %u seconds", 774 WPA_GET_LE32(pos)); 775 pos += 4; 776 777 #ifdef CONFIG_IEEE80211W 778 /* 779 * IGTKdata[variable]: 780 * Key ID[2], IPN[6], IGTK[variable] 781 */ 782 key_len = wpa_cipher_key_len(wpa_s->mesh_rsn->mgmt_group_cipher); 783 if (end - pos >= (int) (2 + 6 + key_len)) { 784 sta->igtk_key_id = WPA_GET_LE16(pos); 785 wpa_printf(MSG_DEBUG, "mesh: IGTKdata - Key ID %u", 786 sta->igtk_key_id); 787 pos += 2; 788 os_memcpy(sta->igtk_rsc, pos, sizeof(sta->igtk_rsc)); 789 wpa_hexdump(MSG_DEBUG, "mesh: IGTKdata - IPN", 790 sta->igtk_rsc, sizeof(sta->igtk_rsc)); 791 pos += 6; 792 os_memcpy(sta->igtk, pos, key_len); 793 sta->igtk_len = key_len; 794 wpa_hexdump_key(MSG_DEBUG, "mesh: IGTKdata - IGTK", 795 sta->igtk, sta->igtk_len); 796 } 797 #endif /* CONFIG_IEEE80211W */ 798 799 free: 800 os_free(crypt); 801 return ret; 802 } 803
