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, 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                         enum key_flag key_flag)
 105 {
 106         struct mesh_rsn *mesh_rsn = ctx;
 107         u8 seq[6];
 108
 109         os_memset(seq, 0, sizeof(seq));
 110
 111         if (addr) {
 112                 wpa_printf(MSG_DEBUG, "AUTH: %s(alg=%d addr=" MACSTR
 113                            " key_idx=%d)",
 114                            __func__, alg, MAC2STR(addr), idx);
 115         } else {
 116                 wpa_printf(MSG_DEBUG, "AUTH: %s(alg=%d key_idx=%d)",
 117                            __func__, alg, idx);
 118         }
 119         wpa_hexdump_key(MSG_DEBUG, "AUTH: set_key - key", key, key_len);
 120
 121         return wpa_drv_set_key(mesh_rsn->wpa_s, alg, addr, idx,
 122                                1, seq, 6, key, key_len, key_flag);
 123 }
 124
 125
 126 static int auth_start_ampe(void *ctx, const u8 *addr)
 127 {
 128         struct mesh_rsn *mesh_rsn = ctx;
 129         struct hostapd_data *hapd;
 130         struct sta_info *sta;
 131
 132         if (mesh_rsn->wpa_s->current_ssid->mode != WPAS_MODE_MESH)
 133                 return -1;
 134
 135         hapd = mesh_rsn->wpa_s->ifmsh->bss[0];
 136         sta = ap_get_sta(hapd, addr);
 137         if (sta)
 138                 eloop_cancel_timeout(mesh_auth_timer, mesh_rsn->wpa_s, sta);
 139
 140         mesh_mpm_auth_peer(mesh_rsn->wpa_s, addr);
 141         return 0;
 142 }
 143
 144
 145 static int __mesh_rsn_auth_init(struct mesh_rsn *rsn, const u8 *addr,
 146                                 enum mfp_options ieee80211w, int ocv)
 147 {
 148         struct wpa_auth_config conf;
 149         static const struct wpa_auth_callbacks cb = {
 150                 .logger = auth_logger,
 151                 .get_psk = auth_get_psk,
 152                 .set_key = auth_set_key,
 153                 .start_ampe = auth_start_ampe,
 154         };
 155         u8 seq[6] = {};
 156
 157         wpa_printf(MSG_DEBUG, "AUTH: Initializing group state machine");
 158
 159         os_memset(&conf, 0, sizeof(conf));
 160         conf.wpa = WPA_PROTO_RSN;
 161         conf.wpa_key_mgmt = WPA_KEY_MGMT_SAE;
 162         conf.wpa_pairwise = rsn->pairwise_cipher;
 163         conf.rsn_pairwise = rsn->pairwise_cipher;
 164         conf.wpa_group = rsn->group_cipher;
 165         conf.eapol_version = 0;
 166         conf.wpa_group_rekey = -1;
 167         conf.wpa_group_update_count = 4;
 168         conf.wpa_pairwise_update_count = 4;
 169         conf.ieee80211w = ieee80211w;
 170         if (ieee80211w != NO_MGMT_FRAME_PROTECTION)
 171                 conf.group_mgmt_cipher = rsn->mgmt_group_cipher;
 172 #ifdef CONFIG_OCV
 173         conf.ocv = ocv;
 174 #endif /* CONFIG_OCV */
 175
 176         rsn->auth = wpa_init(addr, &conf, &cb, rsn);
 177         if (rsn->auth == NULL) {
 178                 wpa_printf(MSG_DEBUG, "AUTH: wpa_init() failed");
 179                 return -1;
 180         }
 181
 182         /* TODO: support rekeying */
 183         rsn->mgtk_len = wpa_cipher_key_len(conf.wpa_group);
 184         if (random_get_bytes(rsn->mgtk, rsn->mgtk_len) < 0)
 185                 return -1;
 186         rsn->mgtk_key_id = 1;
 187
 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                                 KEY_FLAG_GROUP_TX_DEFAULT);
 202         }
 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, KEY_FLAG_GROUP_TX_DEFAULT);
 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         if (cat[1] == PLINK_OPEN && rsn->igtk_len)
 547                 len += 2 + 6 + rsn->igtk_len;
 548
 549         if (2 + AES_BLOCK_SIZE + 2 + len > wpabuf_tailroom(buf)) {
 550                 wpa_printf(MSG_ERROR, "protect frame: buffer too small");
 551                 return -EINVAL;
 552         }
 553
 554         ampe_ie = os_zalloc(2 + len);
 555         if (!ampe_ie) {
 556                 wpa_printf(MSG_ERROR, "protect frame: out of memory");
 557                 return -ENOMEM;
 558         }
 559
 560         /*  IE: AMPE */
 561         ampe_ie[0] = WLAN_EID_AMPE;
 562         ampe_ie[1] = len;
 563         ampe = (struct ieee80211_ampe_ie *) (ampe_ie + 2);
 564
 565         RSN_SELECTOR_PUT(ampe->selected_pairwise_suite,
 566                          RSN_CIPHER_SUITE_CCMP);
 567         os_memcpy(ampe->local_nonce, sta->my_nonce, WPA_NONCE_LEN);
 568         os_memcpy(ampe->peer_nonce, sta->peer_nonce, WPA_NONCE_LEN);
 569
 570         pos = (u8 *) (ampe + 1);
 571         if (cat[1] != PLINK_OPEN)
 572                 goto skip_keys;
 573
 574         /* TODO: Key Replay Counter[8] optionally for
 575          * Mesh Group Key Inform/Acknowledge frames */
 576
 577         /* TODO: static mgtk for now since we don't support rekeying! */
 578         /*
 579          * GTKdata[variable]:
 580          * MGTK[variable] || Key RSC[8] || GTKExpirationTime[4]
 581          */
 582         os_memcpy(pos, rsn->mgtk, rsn->mgtk_len);
 583         pos += rsn->mgtk_len;
 584         wpa_drv_get_seqnum(rsn->wpa_s, NULL, rsn->mgtk_key_id, pos);
 585         pos += WPA_KEY_RSC_LEN;
 586         /* Use fixed GTKExpirationTime for now */
 587         WPA_PUT_LE32(pos, 0xffffffff);
 588         pos += 4;
 589
 590         /*
 591          * IGTKdata[variable]:
 592          * Key ID[2], IPN[6], IGTK[variable]
 593          */
 594         if (rsn->igtk_len) {
 595                 WPA_PUT_LE16(pos, rsn->igtk_key_id);
 596                 pos += 2;
 597                 wpa_drv_get_seqnum(rsn->wpa_s, NULL, rsn->igtk_key_id, pos);
 598                 pos += 6;
 599                 os_memcpy(pos, rsn->igtk, rsn->igtk_len);
 600         }
 601
 602 skip_keys:
 603         wpa_hexdump_key(MSG_DEBUG, "mesh: Plaintext AMPE element",
 604                         ampe_ie, 2 + len);
 605
 606         /* IE: MIC */
 607         wpabuf_put_u8(buf, WLAN_EID_MIC);
 608         wpabuf_put_u8(buf, AES_BLOCK_SIZE);
 609         /* MIC field is output ciphertext */
 610
 611         /* encrypt after MIC */
 612         mic_payload = wpabuf_put(buf, 2 + len + AES_BLOCK_SIZE);
 613
 614         if (aes_siv_encrypt(sta->aek, sizeof(sta->aek), ampe_ie, 2 + len, 3,
 615                             aad, aad_len, mic_payload)) {
 616                 wpa_printf(MSG_ERROR, "protect frame: failed to encrypt");
 617                 ret = -ENOMEM;
 618         }
 619
 620         os_free(ampe_ie);
 621
 622         return ret;
 623 }
 624
 625
 626 int mesh_rsn_process_ampe(struct wpa_supplicant *wpa_s, struct sta_info *sta,
 627                           struct ieee802_11_elems *elems, const u8 *cat,
 628                           const u8 *chosen_pmk,
 629                           const u8 *start, size_t elems_len)
 630 {
 631         int ret = 0;
 632         struct ieee80211_ampe_ie *ampe;
 633         u8 null_nonce[WPA_NONCE_LEN] = {};
 634         u8 ampe_eid;
 635         u8 ampe_ie_len;
 636         u8 *ampe_buf, *crypt = NULL, *pos, *end;
 637         size_t crypt_len;
 638         const u8 *aad[] = { sta->addr, wpa_s->own_addr, cat };
 639         const size_t aad_len[] = { ETH_ALEN, ETH_ALEN,
 640                                    elems->mic ? (elems->mic - 2) - cat : 0 };
 641         size_t key_len;
 642
 643         if (!sta->sae) {
 644                 struct hostapd_data *hapd = wpa_s->ifmsh->bss[0];
 645
 646                 if (!wpa_auth_pmksa_get(hapd->wpa_auth, sta->addr, NULL)) {
 647                         wpa_printf(MSG_INFO,
 648                                    "Mesh RSN: SAE is not prepared yet");
 649                         return -1;
 650                 }
 651                 mesh_rsn_auth_sae_sta(wpa_s, sta);
 652         }
 653
 654         if (chosen_pmk &&
 655             (!sta->sae ||
 656              os_memcmp(chosen_pmk, sta->sae->pmkid, PMKID_LEN) != 0)) {
 657                 wpa_msg(wpa_s, MSG_DEBUG,
 658                         "Mesh RSN: Invalid PMKID (Chosen PMK did not match calculated PMKID)");
 659                 return -1;
 660         }
 661
 662         if (!elems->mic || elems->mic_len < AES_BLOCK_SIZE) {
 663                 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: missing mic ie");
 664                 return -1;
 665         }
 666
 667         ampe_buf = (u8 *) elems->mic + elems->mic_len;
 668         if ((int) elems_len < ampe_buf - start)
 669                 return -1;
 670
 671         crypt_len = elems_len - (elems->mic - start);
 672         if (crypt_len < 2 + AES_BLOCK_SIZE) {
 673                 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: missing ampe ie");
 674                 return -1;
 675         }
 676
 677         /* crypt is modified by siv_decrypt */
 678         crypt = os_zalloc(crypt_len);
 679         if (!crypt) {
 680                 wpa_printf(MSG_ERROR, "Mesh RSN: out of memory");
 681                 ret = -ENOMEM;
 682                 goto free;
 683         }
 684
 685         os_memcpy(crypt, elems->mic, crypt_len);
 686
 687         if (aes_siv_decrypt(sta->aek, sizeof(sta->aek), crypt, crypt_len, 3,
 688                             aad, aad_len, ampe_buf)) {
 689                 wpa_printf(MSG_ERROR, "Mesh RSN: frame verification failed!");
 690                 ret = -2;
 691                 goto free;
 692         }
 693
 694         crypt_len -= AES_BLOCK_SIZE;
 695         wpa_hexdump_key(MSG_DEBUG, "mesh: Decrypted AMPE element",
 696                         ampe_buf, crypt_len);
 697
 698         ampe_eid = *ampe_buf++;
 699         ampe_ie_len = *ampe_buf++;
 700
 701         if (ampe_eid != WLAN_EID_AMPE ||
 702             (size_t) 2 + ampe_ie_len > crypt_len ||
 703             ampe_ie_len < sizeof(struct ieee80211_ampe_ie)) {
 704                 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: invalid ampe ie");
 705                 ret = -1;
 706                 goto free;
 707         }
 708
 709         ampe = (struct ieee80211_ampe_ie *) ampe_buf;
 710         pos = (u8 *) (ampe + 1);
 711         end = ampe_buf + ampe_ie_len;
 712         if (os_memcmp(ampe->peer_nonce, null_nonce, WPA_NONCE_LEN) != 0 &&
 713             os_memcmp(ampe->peer_nonce, sta->my_nonce, WPA_NONCE_LEN) != 0) {
 714                 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: invalid peer nonce");
 715                 ret = -1;
 716                 goto free;
 717         }
 718         os_memcpy(sta->peer_nonce, ampe->local_nonce,
 719                   sizeof(ampe->local_nonce));
 720
 721         /* TODO: Key Replay Counter[8] in Mesh Group Key Inform/Acknowledge
 722          * frames */
 723
 724         /*
 725          * GTKdata shall not be included in Mesh Peering Confirm. While the
 726          * standard does not state the same about IGTKdata, that same constraint
 727          * needs to apply for it. It makes no sense to include the keys in Mesh
 728          * Peering Close frames either, so while the standard does not seem to
 729          * have a shall statement for these, they are described without
 730          * mentioning GTKdata.
 731          *
 732          * An earlier implementation used to add GTKdata to both Mesh Peering
 733          * Open and Mesh Peering Confirm frames, so ignore the possibly present
 734          * GTKdata frame without rejecting the frame as a backwards
 735          * compatibility mechanism.
 736          */
 737         if (cat[1] != PLINK_OPEN) {
 738                 if (end > pos) {
 739                         wpa_hexdump_key(MSG_DEBUG,
 740                                         "mesh: Ignore unexpected GTKdata(etc.) fields in the end of AMPE element in Mesh Peering Confirm/Close",
 741                                         pos, end - pos);
 742                 }
 743                 goto free;
 744         }
 745
 746         /*
 747          * GTKdata[variable]:
 748          * MGTK[variable] || Key RSC[8] || GTKExpirationTime[4]
 749          */
 750         sta->mgtk_key_id = 1; /* FIX: Where to get Key ID? */
 751         key_len = wpa_cipher_key_len(wpa_s->mesh_rsn->group_cipher);
 752         if ((int) key_len + WPA_KEY_RSC_LEN + 4 > end - pos) {
 753                 wpa_dbg(wpa_s, MSG_DEBUG, "mesh: Truncated AMPE element");
 754                 ret = -1;
 755                 goto free;
 756         }
 757         sta->mgtk_len = key_len;
 758         os_memcpy(sta->mgtk, pos, sta->mgtk_len);
 759         wpa_hexdump_key(MSG_DEBUG, "mesh: GTKdata - MGTK",
 760                         sta->mgtk, sta->mgtk_len);
 761         pos += sta->mgtk_len;
 762         wpa_hexdump(MSG_DEBUG, "mesh: GTKdata - MGTK - Key RSC",
 763                     pos, WPA_KEY_RSC_LEN);
 764         os_memcpy(sta->mgtk_rsc, pos, sizeof(sta->mgtk_rsc));
 765         pos += WPA_KEY_RSC_LEN;
 766         wpa_printf(MSG_DEBUG,
 767                    "mesh: GTKdata - MGTK - GTKExpirationTime: %u seconds",
 768                    WPA_GET_LE32(pos));
 769         pos += 4;
 770
 771         /*
 772          * IGTKdata[variable]:
 773          * Key ID[2], IPN[6], IGTK[variable]
 774          */
 775         key_len = wpa_cipher_key_len(wpa_s->mesh_rsn->mgmt_group_cipher);
 776         if (end - pos >= (int) (2 + 6 + key_len)) {
 777                 sta->igtk_key_id = WPA_GET_LE16(pos);
 778                 wpa_printf(MSG_DEBUG, "mesh: IGTKdata - Key ID %u",
 779                            sta->igtk_key_id);
 780                 pos += 2;
 781                 os_memcpy(sta->igtk_rsc, pos, sizeof(sta->igtk_rsc));
 782                 wpa_hexdump(MSG_DEBUG, "mesh: IGTKdata - IPN",
 783                             sta->igtk_rsc, sizeof(sta->igtk_rsc));
 784                 pos += 6;
 785                 os_memcpy(sta->igtk, pos, key_len);
 786                 sta->igtk_len = key_len;
 787                 wpa_hexdump_key(MSG_DEBUG, "mesh: IGTKdata - IGTK",
 788                                 sta->igtk, sta->igtk_len);
 789         }
 790
 791 free:
 792         os_free(crypt);
 793         return ret;
 794 }