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
30 #define MESH_AUTH_BLOCK_DURATION 3600
32 void mesh_auth_timer(void *eloop_ctx, void *user_data)
34 struct wpa_supplicant *wpa_s = eloop_ctx;
35 struct sta_info *sta = user_data;
37 if (sta->sae->state != SAE_ACCEPTED) {
38 wpa_printf(MSG_DEBUG, "AUTH: Re-authenticate with " MACSTR
40 MAC2STR(sta->addr), sta->sae_auth_retry);
41 wpa_msg(wpa_s, MSG_INFO, MESH_SAE_AUTH_FAILURE "addr=" MACSTR,
43 if (sta->sae_auth_retry < MESH_AUTH_RETRY) {
44 mesh_rsn_auth_sae_sta(wpa_s, sta);
46 if (sta->sae_auth_retry > MESH_AUTH_RETRY) {
47 ap_free_sta(wpa_s->ifmsh->bss[0], sta);
51 /* block the STA if exceeded the number of attempts */
52 wpa_mesh_set_plink_state(wpa_s, sta, PLINK_BLOCKED);
53 sta->sae->state = SAE_NOTHING;
54 if (wpa_s->mesh_auth_block_duration <
55 MESH_AUTH_BLOCK_DURATION)
56 wpa_s->mesh_auth_block_duration += 60;
57 eloop_register_timeout(wpa_s->mesh_auth_block_duration,
58 0, mesh_auth_timer, wpa_s, sta);
59 wpa_msg(wpa_s, MSG_INFO, MESH_SAE_AUTH_BLOCKED "addr="
60 MACSTR " duration=%d",
62 wpa_s->mesh_auth_block_duration);
64 sta->sae_auth_retry++;
69 static void auth_logger(void *ctx, const u8 *addr, logger_level level,
73 wpa_printf(MSG_DEBUG, "AUTH: " MACSTR " - %s",
76 wpa_printf(MSG_DEBUG, "AUTH: %s", txt);
80 static const u8 *auth_get_psk(void *ctx, const u8 *addr,
81 const u8 *p2p_dev_addr, const u8 *prev_psk)
83 struct mesh_rsn *mesh_rsn = ctx;
84 struct hostapd_data *hapd = mesh_rsn->wpa_s->ifmsh->bss[0];
85 struct sta_info *sta = ap_get_sta(hapd, addr);
87 wpa_printf(MSG_DEBUG, "AUTH: %s (addr=" MACSTR " prev_psk=%p)",
88 __func__, MAC2STR(addr), prev_psk);
90 if (sta && sta->auth_alg == WLAN_AUTH_SAE) {
91 if (!sta->sae || prev_psk)
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)
103 struct mesh_rsn *mesh_rsn = ctx;
106 os_memset(seq, 0, sizeof(seq));
109 wpa_printf(MSG_DEBUG, "AUTH: %s(alg=%d addr=" MACSTR
111 __func__, alg, MAC2STR(addr), idx);
113 wpa_printf(MSG_DEBUG, "AUTH: %s(alg=%d key_idx=%d)",
116 wpa_hexdump_key(MSG_DEBUG, "AUTH: set_key - key", key, key_len);
118 return wpa_drv_set_key(mesh_rsn->wpa_s, alg, addr, idx,
119 1, seq, 6, key, key_len);
123 static int auth_start_ampe(void *ctx, const u8 *addr)
125 struct mesh_rsn *mesh_rsn = ctx;
126 struct hostapd_data *hapd;
127 struct sta_info *sta;
129 if (mesh_rsn->wpa_s->current_ssid->mode != WPAS_MODE_MESH)
132 hapd = mesh_rsn->wpa_s->ifmsh->bss[0];
133 sta = ap_get_sta(hapd, addr);
135 eloop_cancel_timeout(mesh_auth_timer, mesh_rsn->wpa_s, sta);
137 mesh_mpm_auth_peer(mesh_rsn->wpa_s, addr);
142 static int __mesh_rsn_auth_init(struct mesh_rsn *rsn, const u8 *addr)
144 struct wpa_auth_config conf;
145 struct wpa_auth_callbacks cb;
148 wpa_printf(MSG_DEBUG, "AUTH: Initializing group state machine");
150 os_memset(&conf, 0, sizeof(conf));
152 conf.wpa_key_mgmt = WPA_KEY_MGMT_SAE;
153 conf.wpa_pairwise = WPA_CIPHER_CCMP;
154 conf.rsn_pairwise = WPA_CIPHER_CCMP;
155 conf.wpa_group = WPA_CIPHER_CCMP;
156 conf.eapol_version = 0;
157 conf.wpa_group_rekey = -1;
159 os_memset(&cb, 0, sizeof(cb));
161 cb.logger = auth_logger;
162 cb.get_psk = auth_get_psk;
163 cb.set_key = auth_set_key;
164 cb.start_ampe = auth_start_ampe;
166 rsn->auth = wpa_init(addr, &conf, &cb);
167 if (rsn->auth == NULL) {
168 wpa_printf(MSG_DEBUG, "AUTH: wpa_init() failed");
172 /* TODO: support rekeying */
173 if (random_get_bytes(rsn->mgtk, 16) < 0) {
174 wpa_deinit(rsn->auth);
179 wpa_drv_set_key(rsn->wpa_s, WPA_ALG_IGTK, NULL, 4, 1,
180 seq, sizeof(seq), rsn->mgtk, sizeof(rsn->mgtk));
182 /* group privacy / data frames */
183 wpa_drv_set_key(rsn->wpa_s, WPA_ALG_CCMP, NULL, 1, 1,
184 seq, sizeof(seq), rsn->mgtk, sizeof(rsn->mgtk));
190 static void mesh_rsn_deinit(struct mesh_rsn *rsn)
192 os_memset(rsn->mgtk, 0, sizeof(rsn->mgtk));
194 wpa_deinit(rsn->auth);
198 struct mesh_rsn *mesh_rsn_auth_init(struct wpa_supplicant *wpa_s,
199 struct mesh_conf *conf)
201 struct mesh_rsn *mesh_rsn;
202 struct hostapd_data *bss = wpa_s->ifmsh->bss[0];
206 mesh_rsn = os_zalloc(sizeof(*mesh_rsn));
207 if (mesh_rsn == NULL)
209 mesh_rsn->wpa_s = wpa_s;
211 if (__mesh_rsn_auth_init(mesh_rsn, wpa_s->own_addr) < 0) {
212 mesh_rsn_deinit(mesh_rsn);
217 bss->wpa_auth = mesh_rsn->auth;
219 ie = wpa_auth_get_wpa_ie(mesh_rsn->auth, &ie_len);
220 conf->rsn_ie = (u8 *) ie;
221 conf->rsn_ie_len = ie_len;
223 wpa_supplicant_rsn_supp_set_config(wpa_s, wpa_s->current_ssid);
229 static int index_within_array(const int *array, int idx)
233 for (i = 0; i < idx; i++) {
242 static int mesh_rsn_sae_group(struct wpa_supplicant *wpa_s,
243 struct sae_data *sae)
245 int *groups = wpa_s->ifmsh->bss[0]->conf->sae_groups;
247 /* Configuration may have changed, so validate current index */
248 if (!index_within_array(groups, wpa_s->mesh_rsn->sae_group_index))
252 int group = groups[wpa_s->mesh_rsn->sae_group_index];
256 if (sae_set_group(sae, group) == 0) {
257 wpa_dbg(wpa_s, MSG_DEBUG, "SME: Selected SAE group %d",
261 wpa_s->mesh_rsn->sae_group_index++;
268 static int mesh_rsn_build_sae_commit(struct wpa_supplicant *wpa_s,
269 struct wpa_ssid *ssid,
270 struct sta_info *sta)
272 if (ssid->passphrase == NULL) {
273 wpa_msg(wpa_s, MSG_DEBUG, "SAE: No password available");
277 if (mesh_rsn_sae_group(wpa_s, sta->sae) < 0) {
278 wpa_msg(wpa_s, MSG_DEBUG, "SAE: Failed to select group");
282 return sae_prepare_commit(wpa_s->own_addr, sta->addr,
283 (u8 *) ssid->passphrase,
284 os_strlen(ssid->passphrase), sta->sae);
288 /* initiate new SAE authentication with sta */
289 int mesh_rsn_auth_sae_sta(struct wpa_supplicant *wpa_s,
290 struct sta_info *sta)
292 struct hostapd_data *hapd = wpa_s->ifmsh->bss[0];
293 struct wpa_ssid *ssid = wpa_s->current_ssid;
298 wpa_msg(wpa_s, MSG_DEBUG,
299 "AUTH: No current_ssid known to initiate new SAE");
304 sta->sae = os_zalloc(sizeof(*sta->sae));
305 if (sta->sae == NULL)
309 if (mesh_rsn_build_sae_commit(wpa_s, ssid, sta))
312 wpa_msg(wpa_s, MSG_DEBUG,
313 "AUTH: started authentication with SAE peer: " MACSTR,
316 wpa_supplicant_set_state(wpa_s, WPA_AUTHENTICATING);
317 ret = auth_sae_init_committed(hapd, sta);
321 eloop_cancel_timeout(mesh_auth_timer, wpa_s, sta);
322 rnd = rand() % MESH_AUTH_TIMEOUT;
323 eloop_register_timeout(MESH_AUTH_TIMEOUT + rnd, 0, mesh_auth_timer,
329 void mesh_rsn_get_pmkid(struct mesh_rsn *rsn, struct sta_info *sta, u8 *pmkid)
331 /* don't expect wpa auth to cache the pmkid for now */
332 rsn_pmkid(sta->sae->pmk, PMK_LEN, rsn->wpa_s->own_addr,
334 wpa_key_mgmt_sha256(wpa_auth_sta_key_mgmt(sta->wpa_sm)));
339 mesh_rsn_derive_aek(struct mesh_rsn *rsn, struct sta_info *sta)
341 u8 *myaddr = rsn->wpa_s->own_addr;
342 u8 *peer = sta->addr;
343 u8 *addr1 = peer, *addr2 = myaddr;
344 u8 context[AES_BLOCK_SIZE];
347 RSN_SELECTOR_PUT(context, wpa_cipher_to_suite(0, WPA_CIPHER_GCMP));
349 if (os_memcmp(myaddr, peer, ETH_ALEN) < 0) {
353 os_memcpy(context + 4, addr1, ETH_ALEN);
354 os_memcpy(context + 10, addr2, ETH_ALEN);
356 sha256_prf(sta->sae->pmk, sizeof(sta->sae->pmk), "AEK Derivation",
357 context, sizeof(context), sta->aek, sizeof(sta->aek));
361 /* derive mesh temporal key from pmk */
362 int mesh_rsn_derive_mtk(struct wpa_supplicant *wpa_s, struct sta_info *sta)
366 u16 min_lid, max_lid;
367 size_t nonce_len = sizeof(sta->my_nonce);
368 size_t lid_len = sizeof(sta->my_lid);
369 u8 *myaddr = wpa_s->own_addr;
370 u8 *peer = sta->addr;
371 /* 2 nonces, 2 linkids, akm suite, 2 mac addrs */
372 u8 context[64 + 4 + 4 + 12];
375 if (os_memcmp(sta->my_nonce, sta->peer_nonce, nonce_len) < 0) {
377 max = sta->peer_nonce;
379 min = sta->peer_nonce;
382 os_memcpy(ptr, min, nonce_len);
383 os_memcpy(ptr + nonce_len, max, nonce_len);
384 ptr += 2 * nonce_len;
386 if (sta->my_lid < sta->peer_lid) {
387 min_lid = host_to_le16(sta->my_lid);
388 max_lid = host_to_le16(sta->peer_lid);
390 min_lid = host_to_le16(sta->peer_lid);
391 max_lid = host_to_le16(sta->my_lid);
393 os_memcpy(ptr, &min_lid, lid_len);
394 os_memcpy(ptr + lid_len, &max_lid, lid_len);
398 RSN_SELECTOR_PUT(ptr, wpa_cipher_to_suite(0, WPA_CIPHER_GCMP));
401 if (os_memcmp(myaddr, peer, ETH_ALEN) < 0) {
408 os_memcpy(ptr, min, ETH_ALEN);
409 os_memcpy(ptr + ETH_ALEN, max, ETH_ALEN);
411 sha256_prf(sta->sae->pmk, sizeof(sta->sae->pmk),
412 "Temporal Key Derivation", context, sizeof(context),
413 sta->mtk, sizeof(sta->mtk));
418 void mesh_rsn_init_ampe_sta(struct wpa_supplicant *wpa_s, struct sta_info *sta)
420 if (random_get_bytes(sta->my_nonce, 32) < 0) {
421 wpa_printf(MSG_INFO, "mesh: Failed to derive random nonce");
422 /* TODO: How to handle this more cleanly? */
424 os_memset(sta->peer_nonce, 0, 32);
425 mesh_rsn_derive_aek(wpa_s->mesh_rsn, sta);
429 /* insert AMPE and encrypted MIC at @ie.
430 * @mesh_rsn: mesh RSN context
431 * @sta: STA we're sending to
432 * @cat: pointer to category code in frame header.
433 * @buf: wpabuf to add encrypted AMPE and MIC to.
435 int mesh_rsn_protect_frame(struct mesh_rsn *rsn, struct sta_info *sta,
436 const u8 *cat, struct wpabuf *buf)
438 struct ieee80211_ampe_ie *ampe;
439 u8 const *ie = wpabuf_head_u8(buf) + wpabuf_len(buf);
440 u8 *ampe_ie = NULL, *mic_ie = NULL, *mic_payload;
441 const u8 *aad[] = { rsn->wpa_s->own_addr, sta->addr, cat };
442 const size_t aad_len[] = { ETH_ALEN, ETH_ALEN, ie - cat };
445 if (AES_BLOCK_SIZE + 2 + sizeof(*ampe) + 2 > wpabuf_tailroom(buf)) {
446 wpa_printf(MSG_ERROR, "protect frame: buffer too small");
450 ampe_ie = os_zalloc(2 + sizeof(*ampe));
452 wpa_printf(MSG_ERROR, "protect frame: out of memory");
456 mic_ie = os_zalloc(2 + AES_BLOCK_SIZE);
458 wpa_printf(MSG_ERROR, "protect frame: out of memory");
464 ampe_ie[0] = WLAN_EID_AMPE;
465 ampe_ie[1] = sizeof(*ampe);
466 ampe = (struct ieee80211_ampe_ie *) (ampe_ie + 2);
468 RSN_SELECTOR_PUT(ampe->selected_pairwise_suite,
469 wpa_cipher_to_suite(WPA_PROTO_RSN, WPA_CIPHER_CCMP));
470 os_memcpy(ampe->local_nonce, sta->my_nonce, 32);
471 os_memcpy(ampe->peer_nonce, sta->peer_nonce, 32);
472 /* incomplete: see 13.5.4 */
473 /* TODO: static mgtk for now since we don't support rekeying! */
474 os_memcpy(ampe->mgtk, rsn->mgtk, 16);
475 /* TODO: Populate Key RSC */
476 /* expire in 13 decades or so */
477 os_memset(ampe->key_expiration, 0xff, 4);
480 mic_ie[0] = WLAN_EID_MIC;
481 mic_ie[1] = AES_BLOCK_SIZE;
482 wpabuf_put_data(buf, mic_ie, 2);
483 /* MIC field is output ciphertext */
485 /* encrypt after MIC */
486 mic_payload = (u8 *) wpabuf_put(buf, 2 + sizeof(*ampe) +
489 if (aes_siv_encrypt(sta->aek, ampe_ie, 2 + sizeof(*ampe), 3,
490 aad, aad_len, mic_payload)) {
491 wpa_printf(MSG_ERROR, "protect frame: failed to encrypt");
504 int mesh_rsn_process_ampe(struct wpa_supplicant *wpa_s, struct sta_info *sta,
505 struct ieee802_11_elems *elems, const u8 *cat,
506 const u8 *start, size_t elems_len)
509 struct ieee80211_ampe_ie *ampe;
510 u8 null_nonce[32] = {};
513 u8 *ampe_buf, *crypt = NULL;
515 const u8 *aad[] = { sta->addr, wpa_s->own_addr, cat };
516 const size_t aad_len[] = { ETH_ALEN, ETH_ALEN,
517 (elems->mic - 2) - cat };
519 if (!elems->mic || elems->mic_len < AES_BLOCK_SIZE) {
520 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: missing mic ie");
524 ampe_buf = (u8 *) elems->mic + elems->mic_len;
525 if ((int) elems_len < ampe_buf - start)
528 crypt_len = elems_len - (elems->mic - start);
530 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: missing ampe ie");
534 /* crypt is modified by siv_decrypt */
535 crypt = os_zalloc(crypt_len);
537 wpa_printf(MSG_ERROR, "Mesh RSN: out of memory");
542 os_memcpy(crypt, elems->mic, crypt_len);
544 if (aes_siv_decrypt(sta->aek, crypt, crypt_len, 3,
545 aad, aad_len, ampe_buf)) {
546 wpa_printf(MSG_ERROR, "Mesh RSN: frame verification failed!");
551 ampe_eid = *ampe_buf++;
552 ampe_ie_len = *ampe_buf++;
554 if (ampe_eid != WLAN_EID_AMPE ||
555 ampe_ie_len < sizeof(struct ieee80211_ampe_ie)) {
556 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: invalid ampe ie");
561 ampe = (struct ieee80211_ampe_ie *) ampe_buf;
562 if (os_memcmp(ampe->peer_nonce, null_nonce, 32) != 0 &&
563 os_memcmp(ampe->peer_nonce, sta->my_nonce, 32) != 0) {
564 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: invalid peer nonce");
568 os_memcpy(sta->peer_nonce, ampe->local_nonce,
569 sizeof(ampe->local_nonce));
570 os_memcpy(sta->mgtk, ampe->mgtk, sizeof(ampe->mgtk));
572 /* todo parse mgtk expiration */