2 * WPA Supplicant - Mesh RSN routines
3 * Copyright (c) 2013-2014, cozybit, Inc. All rights reserved.
5 * This software may be distributed under the terms of the BSD license.
6 * See README for more details.
9 #include "utils/includes.h"
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"
24 #include "wpas_glue.h"
28 #define MESH_AUTH_TIMEOUT 10
29 #define MESH_AUTH_RETRY 3
31 void mesh_auth_timer(void *eloop_ctx, void *user_data)
33 struct wpa_supplicant *wpa_s = eloop_ctx;
34 struct sta_info *sta = user_data;
36 if (sta->sae->state != SAE_ACCEPTED) {
37 wpa_printf(MSG_DEBUG, "AUTH: Re-authenticate with " MACSTR
39 MAC2STR(sta->addr), sta->sae_auth_retry);
40 wpa_msg(wpa_s, MSG_INFO, MESH_SAE_AUTH_FAILURE "addr=" MACSTR,
42 if (sta->sae_auth_retry < MESH_AUTH_RETRY) {
43 mesh_rsn_auth_sae_sta(wpa_s, sta);
45 /* block the STA if exceeded the number of attempts */
46 wpa_mesh_set_plink_state(wpa_s, sta, PLINK_BLOCKED);
47 sta->sae->state = SAE_NOTHING;
48 wpa_msg(wpa_s, MSG_INFO, MESH_SAE_AUTH_BLOCKED "addr="
52 sta->sae_auth_retry++;
57 static void auth_logger(void *ctx, const u8 *addr, logger_level level,
61 wpa_printf(MSG_DEBUG, "AUTH: " MACSTR " - %s",
64 wpa_printf(MSG_DEBUG, "AUTH: %s", txt);
68 static const u8 *auth_get_psk(void *ctx, const u8 *addr,
69 const u8 *p2p_dev_addr, const u8 *prev_psk)
71 struct mesh_rsn *mesh_rsn = ctx;
72 struct hostapd_data *hapd = mesh_rsn->wpa_s->ifmsh->bss[0];
73 struct sta_info *sta = ap_get_sta(hapd, addr);
75 wpa_printf(MSG_DEBUG, "AUTH: %s (addr=" MACSTR " prev_psk=%p)",
76 __func__, MAC2STR(addr), prev_psk);
78 if (sta && sta->auth_alg == WLAN_AUTH_SAE) {
79 if (!sta->sae || prev_psk)
88 static int auth_set_key(void *ctx, int vlan_id, enum wpa_alg alg,
89 const u8 *addr, int idx, u8 *key, size_t key_len)
91 struct mesh_rsn *mesh_rsn = ctx;
94 os_memset(seq, 0, sizeof(seq));
97 wpa_printf(MSG_DEBUG, "AUTH: %s(alg=%d addr=" MACSTR
99 __func__, alg, MAC2STR(addr), idx);
101 wpa_printf(MSG_DEBUG, "AUTH: %s(alg=%d key_idx=%d)",
104 wpa_hexdump_key(MSG_DEBUG, "AUTH: set_key - key", key, key_len);
106 return wpa_drv_set_key(mesh_rsn->wpa_s, alg, addr, idx,
107 1, seq, 6, key, key_len);
111 static int auth_start_ampe(void *ctx, const u8 *addr)
113 struct mesh_rsn *mesh_rsn = ctx;
114 struct hostapd_data *hapd;
115 struct sta_info *sta;
117 if (mesh_rsn->wpa_s->current_ssid->mode != WPAS_MODE_MESH)
120 hapd = mesh_rsn->wpa_s->ifmsh->bss[0];
121 sta = ap_get_sta(hapd, addr);
123 eloop_cancel_timeout(mesh_auth_timer, mesh_rsn->wpa_s, sta);
125 mesh_mpm_auth_peer(mesh_rsn->wpa_s, addr);
130 static int __mesh_rsn_auth_init(struct mesh_rsn *rsn, const u8 *addr)
132 struct wpa_auth_config conf;
133 struct wpa_auth_callbacks cb;
136 wpa_printf(MSG_DEBUG, "AUTH: Initializing group state machine");
138 os_memset(&conf, 0, sizeof(conf));
140 conf.wpa_key_mgmt = WPA_KEY_MGMT_SAE;
141 conf.wpa_pairwise = WPA_CIPHER_CCMP;
142 conf.rsn_pairwise = WPA_CIPHER_CCMP;
143 conf.wpa_group = WPA_CIPHER_CCMP;
144 conf.eapol_version = 0;
145 conf.wpa_group_rekey = -1;
147 os_memset(&cb, 0, sizeof(cb));
149 cb.logger = auth_logger;
150 cb.get_psk = auth_get_psk;
151 cb.set_key = auth_set_key;
152 cb.start_ampe = auth_start_ampe;
154 rsn->auth = wpa_init(addr, &conf, &cb);
155 if (rsn->auth == NULL) {
156 wpa_printf(MSG_DEBUG, "AUTH: wpa_init() failed");
160 /* TODO: support rekeying */
161 if (random_get_bytes(rsn->mgtk, 16) < 0) {
162 wpa_deinit(rsn->auth);
167 wpa_drv_set_key(rsn->wpa_s, WPA_ALG_IGTK, NULL, 4, 1,
168 seq, sizeof(seq), rsn->mgtk, sizeof(rsn->mgtk));
170 /* group privacy / data frames */
171 wpa_drv_set_key(rsn->wpa_s, WPA_ALG_CCMP, NULL, 1, 1,
172 seq, sizeof(seq), rsn->mgtk, sizeof(rsn->mgtk));
178 static void mesh_rsn_deinit(struct mesh_rsn *rsn)
180 os_memset(rsn->mgtk, 0, sizeof(rsn->mgtk));
181 wpa_deinit(rsn->auth);
185 struct mesh_rsn *mesh_rsn_auth_init(struct wpa_supplicant *wpa_s,
186 struct mesh_conf *conf)
188 struct mesh_rsn *mesh_rsn;
189 struct hostapd_data *bss = wpa_s->ifmsh->bss[0];
193 mesh_rsn = os_zalloc(sizeof(*mesh_rsn));
194 if (mesh_rsn == NULL)
196 mesh_rsn->wpa_s = wpa_s;
198 if (__mesh_rsn_auth_init(mesh_rsn, wpa_s->own_addr) < 0) {
199 mesh_rsn_deinit(mesh_rsn);
203 bss->wpa_auth = mesh_rsn->auth;
205 ie = wpa_auth_get_wpa_ie(mesh_rsn->auth, &ie_len);
206 conf->ies = (u8 *) ie;
207 conf->ie_len = ie_len;
209 wpa_supplicant_rsn_supp_set_config(wpa_s, wpa_s->current_ssid);
215 static int index_within_array(const int *array, int idx)
219 for (i = 0; i < idx; i++) {
228 static int mesh_rsn_sae_group(struct wpa_supplicant *wpa_s,
229 struct sae_data *sae)
231 int *groups = wpa_s->ifmsh->bss[0]->conf->sae_groups;
233 /* Configuration may have changed, so validate current index */
234 if (!index_within_array(groups, wpa_s->mesh_rsn->sae_group_index))
238 int group = groups[wpa_s->mesh_rsn->sae_group_index];
242 if (sae_set_group(sae, group) == 0) {
243 wpa_dbg(wpa_s, MSG_DEBUG, "SME: Selected SAE group %d",
247 wpa_s->mesh_rsn->sae_group_index++;
254 static int mesh_rsn_build_sae_commit(struct wpa_supplicant *wpa_s,
255 struct wpa_ssid *ssid,
256 struct sta_info *sta)
258 if (ssid->passphrase == NULL) {
259 wpa_msg(wpa_s, MSG_DEBUG, "SAE: No password available");
263 if (mesh_rsn_sae_group(wpa_s, sta->sae) < 0) {
264 wpa_msg(wpa_s, MSG_DEBUG, "SAE: Failed to select group");
268 return sae_prepare_commit(wpa_s->own_addr, sta->addr,
269 (u8 *) ssid->passphrase,
270 os_strlen(ssid->passphrase), sta->sae);
274 /* initiate new SAE authentication with sta */
275 int mesh_rsn_auth_sae_sta(struct wpa_supplicant *wpa_s,
276 struct sta_info *sta)
278 struct hostapd_data *hapd = wpa_s->ifmsh->bss[0];
279 struct wpa_ssid *ssid = wpa_s->current_ssid;
284 wpa_msg(wpa_s, MSG_DEBUG,
285 "AUTH: No current_ssid known to initiate new SAE");
290 sta->sae = os_zalloc(sizeof(*sta->sae));
291 if (sta->sae == NULL)
295 if (mesh_rsn_build_sae_commit(wpa_s, ssid, sta))
298 wpa_msg(wpa_s, MSG_DEBUG,
299 "AUTH: started authentication with SAE peer: " MACSTR,
302 wpa_supplicant_set_state(wpa_s, WPA_AUTHENTICATING);
303 ret = auth_sae_init_committed(hapd, sta);
307 rnd = rand() % MESH_AUTH_TIMEOUT;
308 eloop_register_timeout(MESH_AUTH_TIMEOUT + rnd, 0, mesh_auth_timer,
314 void mesh_rsn_get_pmkid(struct mesh_rsn *rsn, struct sta_info *sta, u8 *pmkid)
316 /* don't expect wpa auth to cache the pmkid for now */
317 rsn_pmkid(sta->sae->pmk, PMK_LEN, rsn->wpa_s->own_addr,
319 wpa_key_mgmt_sha256(wpa_auth_sta_key_mgmt(sta->wpa_sm)));
324 mesh_rsn_derive_aek(struct mesh_rsn *rsn, struct sta_info *sta)
326 u8 *myaddr = rsn->wpa_s->own_addr;
327 u8 *peer = sta->addr;
328 u8 *addr1 = peer, *addr2 = myaddr;
329 u8 context[AES_BLOCK_SIZE];
332 RSN_SELECTOR_PUT(context, wpa_cipher_to_suite(0, WPA_CIPHER_GCMP));
334 if (os_memcmp(myaddr, peer, ETH_ALEN) < 0) {
338 os_memcpy(context + 4, addr1, ETH_ALEN);
339 os_memcpy(context + 10, addr2, ETH_ALEN);
341 sha256_prf(sta->sae->pmk, sizeof(sta->sae->pmk), "AEK Derivation",
342 context, sizeof(context), sta->aek, sizeof(sta->aek));
346 /* derive mesh temporal key from pmk */
347 int mesh_rsn_derive_mtk(struct wpa_supplicant *wpa_s, struct sta_info *sta)
351 u16 min_lid, max_lid;
352 size_t nonce_len = sizeof(sta->my_nonce);
353 size_t lid_len = sizeof(sta->my_lid);
354 u8 *myaddr = wpa_s->own_addr;
355 u8 *peer = sta->addr;
356 /* 2 nonces, 2 linkids, akm suite, 2 mac addrs */
357 u8 context[64 + 4 + 4 + 12];
360 if (os_memcmp(sta->my_nonce, sta->peer_nonce, nonce_len) < 0) {
362 max = sta->peer_nonce;
364 min = sta->peer_nonce;
367 os_memcpy(ptr, min, nonce_len);
368 os_memcpy(ptr + nonce_len, max, nonce_len);
369 ptr += 2 * nonce_len;
371 if (sta->my_lid < sta->peer_lid) {
372 min_lid = host_to_le16(sta->my_lid);
373 max_lid = host_to_le16(sta->peer_lid);
375 min_lid = host_to_le16(sta->peer_lid);
376 max_lid = host_to_le16(sta->my_lid);
378 os_memcpy(ptr, &min_lid, lid_len);
379 os_memcpy(ptr + lid_len, &max_lid, lid_len);
383 RSN_SELECTOR_PUT(ptr, wpa_cipher_to_suite(0, WPA_CIPHER_GCMP));
386 if (os_memcmp(myaddr, peer, ETH_ALEN) < 0) {
393 os_memcpy(ptr, min, ETH_ALEN);
394 os_memcpy(ptr + ETH_ALEN, max, ETH_ALEN);
396 sha256_prf(sta->sae->pmk, sizeof(sta->sae->pmk),
397 "Temporal Key Derivation", context, sizeof(context),
398 sta->mtk, sizeof(sta->mtk));
403 void mesh_rsn_init_ampe_sta(struct wpa_supplicant *wpa_s, struct sta_info *sta)
405 if (random_get_bytes(sta->my_nonce, 32) < 0) {
406 wpa_printf(MSG_INFO, "mesh: Failed to derive random nonce");
407 /* TODO: How to handle this more cleanly? */
409 os_memset(sta->peer_nonce, 0, 32);
410 mesh_rsn_derive_aek(wpa_s->mesh_rsn, sta);
414 /* insert AMPE and encrypted MIC at @ie.
415 * @mesh_rsn: mesh RSN context
416 * @sta: STA we're sending to
417 * @cat: pointer to category code in frame header.
418 * @buf: wpabuf to add encrypted AMPE and MIC to.
420 int mesh_rsn_protect_frame(struct mesh_rsn *rsn, struct sta_info *sta,
421 const u8 *cat, struct wpabuf *buf)
423 struct ieee80211_ampe_ie *ampe;
424 u8 const *ie = wpabuf_head_u8(buf) + wpabuf_len(buf);
425 u8 *ampe_ie = NULL, *mic_ie = NULL, *mic_payload;
426 const u8 *aad[] = { rsn->wpa_s->own_addr, sta->addr, cat };
427 const size_t aad_len[] = { ETH_ALEN, ETH_ALEN, ie - cat };
430 if (AES_BLOCK_SIZE + 2 + sizeof(*ampe) + 2 > wpabuf_tailroom(buf)) {
431 wpa_printf(MSG_ERROR, "protect frame: buffer too small");
435 ampe_ie = os_zalloc(2 + sizeof(*ampe));
437 wpa_printf(MSG_ERROR, "protect frame: out of memory");
441 mic_ie = os_zalloc(2 + AES_BLOCK_SIZE);
443 wpa_printf(MSG_ERROR, "protect frame: out of memory");
449 ampe_ie[0] = WLAN_EID_AMPE;
450 ampe_ie[1] = sizeof(*ampe);
451 ampe = (struct ieee80211_ampe_ie *) (ampe_ie + 2);
453 RSN_SELECTOR_PUT(ampe->selected_pairwise_suite,
454 wpa_cipher_to_suite(WPA_PROTO_RSN, WPA_CIPHER_CCMP));
455 os_memcpy(ampe->local_nonce, sta->my_nonce, 32);
456 os_memcpy(ampe->peer_nonce, sta->peer_nonce, 32);
457 /* incomplete: see 13.5.4 */
458 /* TODO: static mgtk for now since we don't support rekeying! */
459 os_memcpy(ampe->mgtk, rsn->mgtk, 16);
460 /* TODO: Populate Key RSC */
461 /* expire in 13 decades or so */
462 os_memset(ampe->key_expiration, 0xff, 4);
465 mic_ie[0] = WLAN_EID_MIC;
466 mic_ie[1] = AES_BLOCK_SIZE;
467 wpabuf_put_data(buf, mic_ie, 2);
468 /* MIC field is output ciphertext */
470 /* encrypt after MIC */
471 mic_payload = (u8 *) wpabuf_put(buf, 2 + sizeof(*ampe) +
474 if (aes_siv_encrypt(sta->aek, ampe_ie, 2 + sizeof(*ampe), 3,
475 aad, aad_len, mic_payload)) {
476 wpa_printf(MSG_ERROR, "protect frame: failed to encrypt");
489 int mesh_rsn_process_ampe(struct wpa_supplicant *wpa_s, struct sta_info *sta,
490 struct ieee802_11_elems *elems, const u8 *cat,
491 const u8 *start, size_t elems_len)
494 struct ieee80211_ampe_ie *ampe;
495 u8 null_nonce[32] = {};
498 u8 *ampe_buf, *crypt = NULL;
500 const u8 *aad[] = { sta->addr, wpa_s->own_addr, cat };
501 const size_t aad_len[] = { ETH_ALEN, ETH_ALEN,
502 (elems->mic - 2) - cat };
504 if (!elems->mic || elems->mic_len < AES_BLOCK_SIZE) {
505 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: missing mic ie");
509 ampe_buf = (u8 *) elems->mic + elems->mic_len;
510 if ((int) elems_len < ampe_buf - start)
513 crypt_len = elems_len - (elems->mic - start);
515 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: missing ampe ie");
519 /* crypt is modified by siv_decrypt */
520 crypt = os_zalloc(crypt_len);
522 wpa_printf(MSG_ERROR, "Mesh RSN: out of memory");
527 os_memcpy(crypt, elems->mic, crypt_len);
529 if (aes_siv_decrypt(sta->aek, crypt, crypt_len, 3,
530 aad, aad_len, ampe_buf)) {
531 wpa_printf(MSG_ERROR, "Mesh RSN: frame verification failed!");
536 ampe_eid = *ampe_buf++;
537 ampe_ie_len = *ampe_buf++;
539 if (ampe_eid != WLAN_EID_AMPE ||
540 ampe_ie_len < sizeof(struct ieee80211_ampe_ie)) {
541 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: invalid ampe ie");
546 ampe = (struct ieee80211_ampe_ie *) ampe_buf;
547 if (os_memcmp(ampe->peer_nonce, null_nonce, 32) != 0 &&
548 os_memcmp(ampe->peer_nonce, sta->my_nonce, 32) != 0) {
549 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: invalid peer nonce");
553 os_memcpy(sta->peer_nonce, ampe->local_nonce,
554 sizeof(ampe->local_nonce));
555 os_memcpy(sta->mgtk, ampe->mgtk, sizeof(ampe->mgtk));
557 /* todo parse mgtk expiration */