wpa_supplicant/mesh_rsn.c

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