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;
49 sta->sae_auth_retry++;
54 static void auth_logger(void *ctx, const u8 *addr, logger_level level,
58 wpa_printf(MSG_DEBUG, "AUTH: " MACSTR " - %s",
61 wpa_printf(MSG_DEBUG, "AUTH: %s", txt);
65 static const u8 *auth_get_psk(void *ctx, const u8 *addr,
66 const u8 *p2p_dev_addr, const u8 *prev_psk)
68 struct mesh_rsn *mesh_rsn = ctx;
69 struct hostapd_data *hapd = mesh_rsn->wpa_s->ifmsh->bss[0];
70 struct sta_info *sta = ap_get_sta(hapd, addr);
72 wpa_printf(MSG_DEBUG, "AUTH: %s (addr=" MACSTR " prev_psk=%p)",
73 __func__, MAC2STR(addr), prev_psk);
75 if (sta && sta->auth_alg == WLAN_AUTH_SAE) {
76 if (!sta->sae || prev_psk)
85 static int auth_set_key(void *ctx, int vlan_id, enum wpa_alg alg,
86 const u8 *addr, int idx, u8 *key, size_t key_len)
88 struct mesh_rsn *mesh_rsn = ctx;
91 os_memset(seq, 0, sizeof(seq));
94 wpa_printf(MSG_DEBUG, "AUTH: %s(alg=%d addr=" MACSTR
96 __func__, alg, MAC2STR(addr), idx);
98 wpa_printf(MSG_DEBUG, "AUTH: %s(alg=%d key_idx=%d)",
101 wpa_hexdump_key(MSG_DEBUG, "AUTH: set_key - key", key, key_len);
103 return wpa_drv_set_key(mesh_rsn->wpa_s, alg, addr, idx,
104 1, seq, 6, key, key_len);
108 static int auth_start_ampe(void *ctx, const u8 *addr)
110 struct mesh_rsn *mesh_rsn = ctx;
111 struct hostapd_data *hapd;
112 struct sta_info *sta;
114 if (mesh_rsn->wpa_s->current_ssid->mode != WPAS_MODE_MESH)
117 hapd = mesh_rsn->wpa_s->ifmsh->bss[0];
118 sta = ap_get_sta(hapd, addr);
120 eloop_cancel_timeout(mesh_auth_timer, mesh_rsn->wpa_s, sta);
122 mesh_mpm_auth_peer(mesh_rsn->wpa_s, addr);
127 static int __mesh_rsn_auth_init(struct mesh_rsn *rsn, const u8 *addr)
129 struct wpa_auth_config conf;
130 struct wpa_auth_callbacks cb;
133 wpa_printf(MSG_DEBUG, "AUTH: Initializing group state machine");
135 os_memset(&conf, 0, sizeof(conf));
137 conf.wpa_key_mgmt = WPA_KEY_MGMT_SAE;
138 conf.wpa_pairwise = WPA_CIPHER_CCMP;
139 conf.rsn_pairwise = WPA_CIPHER_CCMP;
140 conf.wpa_group = WPA_CIPHER_CCMP;
141 conf.eapol_version = 0;
142 conf.wpa_group_rekey = -1;
144 os_memset(&cb, 0, sizeof(cb));
146 cb.logger = auth_logger;
147 cb.get_psk = auth_get_psk;
148 cb.set_key = auth_set_key;
149 cb.start_ampe = auth_start_ampe;
151 rsn->auth = wpa_init(addr, &conf, &cb);
152 if (rsn->auth == NULL) {
153 wpa_printf(MSG_DEBUG, "AUTH: wpa_init() failed");
157 /* TODO: support rekeying */
158 if (random_get_bytes(rsn->mgtk, 16) < 0) {
159 wpa_deinit(rsn->auth);
164 wpa_drv_set_key(rsn->wpa_s, WPA_ALG_IGTK, NULL, 4, 1,
165 seq, sizeof(seq), rsn->mgtk, sizeof(rsn->mgtk));
167 /* group privacy / data frames */
168 wpa_drv_set_key(rsn->wpa_s, WPA_ALG_CCMP, NULL, 1, 1,
169 seq, sizeof(seq), rsn->mgtk, sizeof(rsn->mgtk));
175 static void mesh_rsn_deinit(struct mesh_rsn *rsn)
177 os_memset(rsn->mgtk, 0, sizeof(rsn->mgtk));
178 wpa_deinit(rsn->auth);
182 struct mesh_rsn *mesh_rsn_auth_init(struct wpa_supplicant *wpa_s,
183 struct mesh_conf *conf)
185 struct mesh_rsn *mesh_rsn;
186 struct hostapd_data *bss = wpa_s->ifmsh->bss[0];
190 mesh_rsn = os_zalloc(sizeof(*mesh_rsn));
191 if (mesh_rsn == NULL)
193 mesh_rsn->wpa_s = wpa_s;
195 if (__mesh_rsn_auth_init(mesh_rsn, wpa_s->own_addr) < 0) {
196 mesh_rsn_deinit(mesh_rsn);
200 bss->wpa_auth = mesh_rsn->auth;
202 ie = wpa_auth_get_wpa_ie(mesh_rsn->auth, &ie_len);
203 conf->ies = (u8 *) ie;
204 conf->ie_len = ie_len;
206 wpa_supplicant_rsn_supp_set_config(wpa_s, wpa_s->current_ssid);
212 static int index_within_array(const int *array, int idx)
216 for (i = 0; i < idx; i++) {
225 static int mesh_rsn_sae_group(struct wpa_supplicant *wpa_s,
226 struct sae_data *sae)
228 int *groups = wpa_s->ifmsh->bss[0]->conf->sae_groups;
230 /* Configuration may have changed, so validate current index */
231 if (!index_within_array(groups, wpa_s->mesh_rsn->sae_group_index))
235 int group = groups[wpa_s->mesh_rsn->sae_group_index];
239 if (sae_set_group(sae, group) == 0) {
240 wpa_dbg(wpa_s, MSG_DEBUG, "SME: Selected SAE group %d",
244 wpa_s->mesh_rsn->sae_group_index++;
251 static int mesh_rsn_build_sae_commit(struct wpa_supplicant *wpa_s,
252 struct wpa_ssid *ssid,
253 struct sta_info *sta)
255 if (ssid->passphrase == NULL) {
256 wpa_msg(wpa_s, MSG_DEBUG, "SAE: No password available");
260 if (mesh_rsn_sae_group(wpa_s, sta->sae) < 0) {
261 wpa_msg(wpa_s, MSG_DEBUG, "SAE: Failed to select group");
265 return sae_prepare_commit(wpa_s->own_addr, sta->addr,
266 (u8 *) ssid->passphrase,
267 os_strlen(ssid->passphrase), sta->sae);
271 /* initiate new SAE authentication with sta */
272 int mesh_rsn_auth_sae_sta(struct wpa_supplicant *wpa_s,
273 struct sta_info *sta)
275 struct hostapd_data *hapd = wpa_s->ifmsh->bss[0];
276 struct wpa_ssid *ssid = wpa_s->current_ssid;
281 wpa_msg(wpa_s, MSG_DEBUG,
282 "AUTH: No current_ssid known to initiate new SAE");
287 sta->sae = os_zalloc(sizeof(*sta->sae));
288 if (sta->sae == NULL)
292 if (mesh_rsn_build_sae_commit(wpa_s, ssid, sta))
295 wpa_msg(wpa_s, MSG_DEBUG,
296 "AUTH: started authentication with SAE peer: " MACSTR,
299 wpa_supplicant_set_state(wpa_s, WPA_AUTHENTICATING);
300 ret = auth_sae_init_committed(hapd, sta);
304 rnd = rand() % MESH_AUTH_TIMEOUT;
305 eloop_register_timeout(MESH_AUTH_TIMEOUT + rnd, 0, mesh_auth_timer,
311 void mesh_rsn_get_pmkid(struct mesh_rsn *rsn, struct sta_info *sta, u8 *pmkid)
313 /* don't expect wpa auth to cache the pmkid for now */
314 rsn_pmkid(sta->sae->pmk, PMK_LEN, rsn->wpa_s->own_addr,
316 wpa_key_mgmt_sha256(wpa_auth_sta_key_mgmt(sta->wpa_sm)));
321 mesh_rsn_derive_aek(struct mesh_rsn *rsn, struct sta_info *sta)
323 u8 *myaddr = rsn->wpa_s->own_addr;
324 u8 *peer = sta->addr;
325 u8 *addr1 = peer, *addr2 = myaddr;
326 u8 context[AES_BLOCK_SIZE];
329 RSN_SELECTOR_PUT(context, wpa_cipher_to_suite(0, WPA_CIPHER_GCMP));
331 if (os_memcmp(myaddr, peer, ETH_ALEN) < 0) {
335 os_memcpy(context + 4, addr1, ETH_ALEN);
336 os_memcpy(context + 10, addr2, ETH_ALEN);
338 sha256_prf(sta->sae->pmk, sizeof(sta->sae->pmk), "AEK Derivation",
339 context, sizeof(context), sta->aek, sizeof(sta->aek));
343 /* derive mesh temporal key from pmk */
344 int mesh_rsn_derive_mtk(struct wpa_supplicant *wpa_s, struct sta_info *sta)
348 u16 min_lid, max_lid;
349 size_t nonce_len = sizeof(sta->my_nonce);
350 size_t lid_len = sizeof(sta->my_lid);
351 u8 *myaddr = wpa_s->own_addr;
352 u8 *peer = sta->addr;
353 /* 2 nonces, 2 linkids, akm suite, 2 mac addrs */
354 u8 context[64 + 4 + 4 + 12];
357 if (os_memcmp(sta->my_nonce, sta->peer_nonce, nonce_len) < 0) {
359 max = sta->peer_nonce;
361 min = sta->peer_nonce;
364 os_memcpy(ptr, min, nonce_len);
365 os_memcpy(ptr + nonce_len, max, nonce_len);
366 ptr += 2 * nonce_len;
368 if (sta->my_lid < sta->peer_lid) {
369 min_lid = host_to_le16(sta->my_lid);
370 max_lid = host_to_le16(sta->peer_lid);
372 min_lid = host_to_le16(sta->peer_lid);
373 max_lid = host_to_le16(sta->my_lid);
375 os_memcpy(ptr, &min_lid, lid_len);
376 os_memcpy(ptr + lid_len, &max_lid, lid_len);
380 RSN_SELECTOR_PUT(ptr, wpa_cipher_to_suite(0, WPA_CIPHER_GCMP));
383 if (os_memcmp(myaddr, peer, ETH_ALEN) < 0) {
390 os_memcpy(ptr, min, ETH_ALEN);
391 os_memcpy(ptr + ETH_ALEN, max, ETH_ALEN);
393 sha256_prf(sta->sae->pmk, sizeof(sta->sae->pmk),
394 "Temporal Key Derivation", context, sizeof(context),
395 sta->mtk, sizeof(sta->mtk));
400 void mesh_rsn_init_ampe_sta(struct wpa_supplicant *wpa_s, struct sta_info *sta)
402 if (random_get_bytes(sta->my_nonce, 32) < 0) {
403 wpa_printf(MSG_INFO, "mesh: Failed to derive random nonce");
404 /* TODO: How to handle this more cleanly? */
406 os_memset(sta->peer_nonce, 0, 32);
407 mesh_rsn_derive_aek(wpa_s->mesh_rsn, sta);
411 /* insert AMPE and encrypted MIC at @ie.
412 * @mesh_rsn: mesh RSN context
413 * @sta: STA we're sending to
414 * @cat: pointer to category code in frame header.
415 * @buf: wpabuf to add encrypted AMPE and MIC to.
417 int mesh_rsn_protect_frame(struct mesh_rsn *rsn, struct sta_info *sta,
418 const u8 *cat, struct wpabuf *buf)
420 struct ieee80211_ampe_ie *ampe;
421 u8 const *ie = wpabuf_head_u8(buf) + wpabuf_len(buf);
422 u8 *ampe_ie = NULL, *mic_ie = NULL, *mic_payload;
423 const u8 *aad[] = { rsn->wpa_s->own_addr, sta->addr, cat };
424 const size_t aad_len[] = { ETH_ALEN, ETH_ALEN, ie - cat };
427 if (AES_BLOCK_SIZE + 2 + sizeof(*ampe) + 2 > wpabuf_tailroom(buf)) {
428 wpa_printf(MSG_ERROR, "protect frame: buffer too small");
432 ampe_ie = os_zalloc(2 + sizeof(*ampe));
434 wpa_printf(MSG_ERROR, "protect frame: out of memory");
438 mic_ie = os_zalloc(2 + AES_BLOCK_SIZE);
440 wpa_printf(MSG_ERROR, "protect frame: out of memory");
446 ampe_ie[0] = WLAN_EID_AMPE;
447 ampe_ie[1] = sizeof(*ampe);
448 ampe = (struct ieee80211_ampe_ie *) (ampe_ie + 2);
450 RSN_SELECTOR_PUT(ampe->selected_pairwise_suite,
451 wpa_cipher_to_suite(WPA_PROTO_RSN, WPA_CIPHER_CCMP));
452 os_memcpy(ampe->local_nonce, sta->my_nonce, 32);
453 os_memcpy(ampe->peer_nonce, sta->peer_nonce, 32);
454 /* incomplete: see 13.5.4 */
455 /* TODO: static mgtk for now since we don't support rekeying! */
456 os_memcpy(ampe->mgtk, rsn->mgtk, 16);
457 /* TODO: Populate Key RSC */
458 /* expire in 13 decades or so */
459 os_memset(ampe->key_expiration, 0xff, 4);
462 mic_ie[0] = WLAN_EID_MIC;
463 mic_ie[1] = AES_BLOCK_SIZE;
464 wpabuf_put_data(buf, mic_ie, 2);
465 /* MIC field is output ciphertext */
467 /* encrypt after MIC */
468 mic_payload = (u8 *) wpabuf_put(buf, 2 + sizeof(*ampe) +
471 if (aes_siv_encrypt(sta->aek, ampe_ie, 2 + sizeof(*ampe), 3,
472 aad, aad_len, mic_payload)) {
473 wpa_printf(MSG_ERROR, "protect frame: failed to encrypt");
486 int mesh_rsn_process_ampe(struct wpa_supplicant *wpa_s, struct sta_info *sta,
487 struct ieee802_11_elems *elems, const u8 *cat,
488 const u8 *start, size_t elems_len)
491 struct ieee80211_ampe_ie *ampe;
492 u8 null_nonce[32] = {};
495 u8 *ampe_buf, *crypt = NULL;
497 const u8 *aad[] = { sta->addr, wpa_s->own_addr, cat };
498 const size_t aad_len[] = { ETH_ALEN, ETH_ALEN,
499 (elems->mic - 2) - cat };
501 if (!elems->mic || elems->mic_len < AES_BLOCK_SIZE) {
502 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: missing mic ie");
506 ampe_buf = (u8 *) elems->mic + elems->mic_len;
507 if ((int) elems_len < ampe_buf - start)
510 crypt_len = elems_len - (elems->mic - start);
512 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: missing ampe ie");
516 /* crypt is modified by siv_decrypt */
517 crypt = os_zalloc(crypt_len);
519 wpa_printf(MSG_ERROR, "Mesh RSN: out of memory");
524 os_memcpy(crypt, elems->mic, crypt_len);
526 if (aes_siv_decrypt(sta->aek, crypt, crypt_len, 3,
527 aad, aad_len, ampe_buf)) {
528 wpa_printf(MSG_ERROR, "Mesh RSN: frame verification failed!");
533 ampe_eid = *ampe_buf++;
534 ampe_ie_len = *ampe_buf++;
536 if (ampe_eid != WLAN_EID_AMPE ||
537 ampe_ie_len < sizeof(struct ieee80211_ampe_ie)) {
538 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: invalid ampe ie");
543 ampe = (struct ieee80211_ampe_ie *) ampe_buf;
544 if (os_memcmp(ampe->peer_nonce, null_nonce, 32) != 0 &&
545 os_memcmp(ampe->peer_nonce, sta->my_nonce, 32) != 0) {
546 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: invalid peer nonce");
550 os_memcpy(sta->peer_nonce, ampe->local_nonce,
551 sizeof(ampe->local_nonce));
552 os_memcpy(sta->mgtk, ampe->mgtk, sizeof(ampe->mgtk));
554 /* todo parse mgtk expiration */