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;
35 struct hostapd_data *hapd;
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 hapd = wpa_s->ifmsh->bss[0];
48 if (sta->sae_auth_retry > MESH_AUTH_RETRY) {
49 ap_free_sta(hapd, sta);
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",
59 hapd->conf->ap_max_inactivity);
61 sta->sae_auth_retry++;
66 static void auth_logger(void *ctx, const u8 *addr, logger_level level,
70 wpa_printf(MSG_DEBUG, "AUTH: " MACSTR " - %s",
73 wpa_printf(MSG_DEBUG, "AUTH: %s", txt);
77 static const u8 *auth_get_psk(void *ctx, const u8 *addr,
78 const u8 *p2p_dev_addr, const u8 *prev_psk)
80 struct mesh_rsn *mesh_rsn = ctx;
81 struct hostapd_data *hapd = mesh_rsn->wpa_s->ifmsh->bss[0];
82 struct sta_info *sta = ap_get_sta(hapd, addr);
84 wpa_printf(MSG_DEBUG, "AUTH: %s (addr=" MACSTR " prev_psk=%p)",
85 __func__, MAC2STR(addr), prev_psk);
87 if (sta && sta->auth_alg == WLAN_AUTH_SAE) {
88 if (!sta->sae || prev_psk)
97 static int auth_set_key(void *ctx, int vlan_id, enum wpa_alg alg,
98 const u8 *addr, int idx, u8 *key, size_t key_len)
100 struct mesh_rsn *mesh_rsn = ctx;
103 os_memset(seq, 0, sizeof(seq));
106 wpa_printf(MSG_DEBUG, "AUTH: %s(alg=%d addr=" MACSTR
108 __func__, alg, MAC2STR(addr), idx);
110 wpa_printf(MSG_DEBUG, "AUTH: %s(alg=%d key_idx=%d)",
113 wpa_hexdump_key(MSG_DEBUG, "AUTH: set_key - key", key, key_len);
115 return wpa_drv_set_key(mesh_rsn->wpa_s, alg, addr, idx,
116 1, seq, 6, key, key_len);
120 static int auth_start_ampe(void *ctx, const u8 *addr)
122 struct mesh_rsn *mesh_rsn = ctx;
123 struct hostapd_data *hapd;
124 struct sta_info *sta;
126 if (mesh_rsn->wpa_s->current_ssid->mode != WPAS_MODE_MESH)
129 hapd = mesh_rsn->wpa_s->ifmsh->bss[0];
130 sta = ap_get_sta(hapd, addr);
132 eloop_cancel_timeout(mesh_auth_timer, mesh_rsn->wpa_s, sta);
134 mesh_mpm_auth_peer(mesh_rsn->wpa_s, addr);
139 static int __mesh_rsn_auth_init(struct mesh_rsn *rsn, const u8 *addr)
141 struct wpa_auth_config conf;
142 struct wpa_auth_callbacks cb;
145 wpa_printf(MSG_DEBUG, "AUTH: Initializing group state machine");
147 os_memset(&conf, 0, sizeof(conf));
149 conf.wpa_key_mgmt = WPA_KEY_MGMT_SAE;
150 conf.wpa_pairwise = WPA_CIPHER_CCMP;
151 conf.rsn_pairwise = WPA_CIPHER_CCMP;
152 conf.wpa_group = WPA_CIPHER_CCMP;
153 conf.eapol_version = 0;
154 conf.wpa_group_rekey = -1;
156 os_memset(&cb, 0, sizeof(cb));
158 cb.logger = auth_logger;
159 cb.get_psk = auth_get_psk;
160 cb.set_key = auth_set_key;
161 cb.start_ampe = auth_start_ampe;
163 rsn->auth = wpa_init(addr, &conf, &cb);
164 if (rsn->auth == NULL) {
165 wpa_printf(MSG_DEBUG, "AUTH: wpa_init() failed");
169 /* TODO: support rekeying */
170 if (random_get_bytes(rsn->mgtk, 16) < 0)
174 wpa_drv_set_key(rsn->wpa_s, WPA_ALG_IGTK, NULL, 4, 1,
175 seq, sizeof(seq), rsn->mgtk, sizeof(rsn->mgtk));
177 /* group privacy / data frames */
178 wpa_drv_set_key(rsn->wpa_s, WPA_ALG_CCMP, NULL, 1, 1,
179 seq, sizeof(seq), rsn->mgtk, sizeof(rsn->mgtk));
185 static void mesh_rsn_deinit(struct mesh_rsn *rsn)
187 os_memset(rsn->mgtk, 0, sizeof(rsn->mgtk));
189 wpa_deinit(rsn->auth);
193 struct mesh_rsn *mesh_rsn_auth_init(struct wpa_supplicant *wpa_s,
194 struct mesh_conf *conf)
196 struct mesh_rsn *mesh_rsn;
197 struct hostapd_data *bss = wpa_s->ifmsh->bss[0];
201 mesh_rsn = os_zalloc(sizeof(*mesh_rsn));
202 if (mesh_rsn == NULL)
204 mesh_rsn->wpa_s = wpa_s;
206 if (__mesh_rsn_auth_init(mesh_rsn, wpa_s->own_addr) < 0) {
207 mesh_rsn_deinit(mesh_rsn);
212 bss->wpa_auth = mesh_rsn->auth;
214 ie = wpa_auth_get_wpa_ie(mesh_rsn->auth, &ie_len);
215 conf->rsn_ie = (u8 *) ie;
216 conf->rsn_ie_len = ie_len;
218 wpa_supplicant_rsn_supp_set_config(wpa_s, wpa_s->current_ssid);
224 static int index_within_array(const int *array, int idx)
228 for (i = 0; i < idx; i++) {
237 static int mesh_rsn_sae_group(struct wpa_supplicant *wpa_s,
238 struct sae_data *sae)
240 int *groups = wpa_s->ifmsh->bss[0]->conf->sae_groups;
242 /* Configuration may have changed, so validate current index */
243 if (!index_within_array(groups, wpa_s->mesh_rsn->sae_group_index))
247 int group = groups[wpa_s->mesh_rsn->sae_group_index];
251 if (sae_set_group(sae, group) == 0) {
252 wpa_dbg(wpa_s, MSG_DEBUG, "SME: Selected SAE group %d",
256 wpa_s->mesh_rsn->sae_group_index++;
263 static int mesh_rsn_build_sae_commit(struct wpa_supplicant *wpa_s,
264 struct wpa_ssid *ssid,
265 struct sta_info *sta)
267 if (ssid->passphrase == NULL) {
268 wpa_msg(wpa_s, MSG_DEBUG, "SAE: No password available");
272 if (mesh_rsn_sae_group(wpa_s, sta->sae) < 0) {
273 wpa_msg(wpa_s, MSG_DEBUG, "SAE: Failed to select group");
277 return sae_prepare_commit(wpa_s->own_addr, sta->addr,
278 (u8 *) ssid->passphrase,
279 os_strlen(ssid->passphrase), sta->sae);
283 /* initiate new SAE authentication with sta */
284 int mesh_rsn_auth_sae_sta(struct wpa_supplicant *wpa_s,
285 struct sta_info *sta)
287 struct hostapd_data *hapd = wpa_s->ifmsh->bss[0];
288 struct wpa_ssid *ssid = wpa_s->current_ssid;
289 struct rsn_pmksa_cache_entry *pmksa;
294 wpa_msg(wpa_s, MSG_DEBUG,
295 "AUTH: No current_ssid known to initiate new SAE");
300 sta->sae = os_zalloc(sizeof(*sta->sae));
301 if (sta->sae == NULL)
305 pmksa = wpa_auth_pmksa_get(hapd->wpa_auth, sta->addr);
308 sta->wpa_sm = wpa_auth_sta_init(hapd->wpa_auth,
311 wpa_printf(MSG_ERROR,
312 "mesh: Failed to initialize RSN state machine");
316 wpa_printf(MSG_DEBUG,
317 "AUTH: Mesh PMKSA cache entry found for " MACSTR
318 " - try to use PMKSA caching instead of new SAE authentication",
320 wpa_auth_pmksa_set_to_sm(pmksa, sta->wpa_sm, hapd->wpa_auth,
321 sta->sae->pmkid, sta->sae->pmk);
322 sae_accept_sta(hapd, sta);
323 sta->mesh_sae_pmksa_caching = 1;
326 sta->mesh_sae_pmksa_caching = 0;
328 if (mesh_rsn_build_sae_commit(wpa_s, ssid, sta))
331 wpa_msg(wpa_s, MSG_DEBUG,
332 "AUTH: started authentication with SAE peer: " MACSTR,
335 wpa_supplicant_set_state(wpa_s, WPA_AUTHENTICATING);
336 ret = auth_sae_init_committed(hapd, sta);
340 eloop_cancel_timeout(mesh_auth_timer, wpa_s, sta);
341 rnd = rand() % MESH_AUTH_TIMEOUT;
342 eloop_register_timeout(MESH_AUTH_TIMEOUT + rnd, 0, mesh_auth_timer,
348 void mesh_rsn_get_pmkid(struct mesh_rsn *rsn, struct sta_info *sta, u8 *pmkid)
350 os_memcpy(pmkid, sta->sae->pmkid, SAE_PMKID_LEN);
355 mesh_rsn_derive_aek(struct mesh_rsn *rsn, struct sta_info *sta)
357 u8 *myaddr = rsn->wpa_s->own_addr;
358 u8 *peer = sta->addr;
359 u8 *addr1 = peer, *addr2 = myaddr;
360 u8 context[AES_BLOCK_SIZE];
363 RSN_SELECTOR_PUT(context, wpa_cipher_to_suite(0, WPA_CIPHER_GCMP));
365 if (os_memcmp(myaddr, peer, ETH_ALEN) < 0) {
369 os_memcpy(context + 4, addr1, ETH_ALEN);
370 os_memcpy(context + 10, addr2, ETH_ALEN);
372 sha256_prf(sta->sae->pmk, sizeof(sta->sae->pmk), "AEK Derivation",
373 context, sizeof(context), sta->aek, sizeof(sta->aek));
377 /* derive mesh temporal key from pmk */
378 int mesh_rsn_derive_mtk(struct wpa_supplicant *wpa_s, struct sta_info *sta)
382 u16 min_lid, max_lid;
383 size_t nonce_len = sizeof(sta->my_nonce);
384 size_t lid_len = sizeof(sta->my_lid);
385 u8 *myaddr = wpa_s->own_addr;
386 u8 *peer = sta->addr;
387 /* 2 nonces, 2 linkids, akm suite, 2 mac addrs */
388 u8 context[64 + 4 + 4 + 12];
391 if (os_memcmp(sta->my_nonce, sta->peer_nonce, nonce_len) < 0) {
393 max = sta->peer_nonce;
395 min = sta->peer_nonce;
398 os_memcpy(ptr, min, nonce_len);
399 os_memcpy(ptr + nonce_len, max, nonce_len);
400 ptr += 2 * nonce_len;
402 if (sta->my_lid < sta->peer_lid) {
403 min_lid = host_to_le16(sta->my_lid);
404 max_lid = host_to_le16(sta->peer_lid);
406 min_lid = host_to_le16(sta->peer_lid);
407 max_lid = host_to_le16(sta->my_lid);
409 os_memcpy(ptr, &min_lid, lid_len);
410 os_memcpy(ptr + lid_len, &max_lid, lid_len);
414 RSN_SELECTOR_PUT(ptr, wpa_cipher_to_suite(0, WPA_CIPHER_GCMP));
417 if (os_memcmp(myaddr, peer, ETH_ALEN) < 0) {
424 os_memcpy(ptr, min, ETH_ALEN);
425 os_memcpy(ptr + ETH_ALEN, max, ETH_ALEN);
427 sha256_prf(sta->sae->pmk, sizeof(sta->sae->pmk),
428 "Temporal Key Derivation", context, sizeof(context),
429 sta->mtk, sizeof(sta->mtk));
434 void mesh_rsn_init_ampe_sta(struct wpa_supplicant *wpa_s, struct sta_info *sta)
436 if (random_get_bytes(sta->my_nonce, 32) < 0) {
437 wpa_printf(MSG_INFO, "mesh: Failed to derive random nonce");
438 /* TODO: How to handle this more cleanly? */
440 os_memset(sta->peer_nonce, 0, 32);
441 mesh_rsn_derive_aek(wpa_s->mesh_rsn, sta);
445 /* insert AMPE and encrypted MIC at @ie.
446 * @mesh_rsn: mesh RSN context
447 * @sta: STA we're sending to
448 * @cat: pointer to category code in frame header.
449 * @buf: wpabuf to add encrypted AMPE and MIC to.
451 int mesh_rsn_protect_frame(struct mesh_rsn *rsn, struct sta_info *sta,
452 const u8 *cat, struct wpabuf *buf)
454 struct ieee80211_ampe_ie *ampe;
455 u8 const *ie = wpabuf_head_u8(buf) + wpabuf_len(buf);
456 u8 *ampe_ie = NULL, *mic_ie = NULL, *mic_payload;
457 const u8 *aad[] = { rsn->wpa_s->own_addr, sta->addr, cat };
458 const size_t aad_len[] = { ETH_ALEN, ETH_ALEN, ie - cat };
461 if (AES_BLOCK_SIZE + 2 + sizeof(*ampe) + 2 > wpabuf_tailroom(buf)) {
462 wpa_printf(MSG_ERROR, "protect frame: buffer too small");
466 ampe_ie = os_zalloc(2 + sizeof(*ampe));
468 wpa_printf(MSG_ERROR, "protect frame: out of memory");
472 mic_ie = os_zalloc(2 + AES_BLOCK_SIZE);
474 wpa_printf(MSG_ERROR, "protect frame: out of memory");
480 ampe_ie[0] = WLAN_EID_AMPE;
481 ampe_ie[1] = sizeof(*ampe);
482 ampe = (struct ieee80211_ampe_ie *) (ampe_ie + 2);
484 RSN_SELECTOR_PUT(ampe->selected_pairwise_suite,
485 wpa_cipher_to_suite(WPA_PROTO_RSN, WPA_CIPHER_CCMP));
486 os_memcpy(ampe->local_nonce, sta->my_nonce, 32);
487 os_memcpy(ampe->peer_nonce, sta->peer_nonce, 32);
488 /* incomplete: see 13.5.4 */
489 /* TODO: static mgtk for now since we don't support rekeying! */
490 os_memcpy(ampe->mgtk, rsn->mgtk, 16);
491 /* TODO: Populate Key RSC */
492 /* expire in 13 decades or so */
493 os_memset(ampe->key_expiration, 0xff, 4);
496 mic_ie[0] = WLAN_EID_MIC;
497 mic_ie[1] = AES_BLOCK_SIZE;
498 wpabuf_put_data(buf, mic_ie, 2);
499 /* MIC field is output ciphertext */
501 /* encrypt after MIC */
502 mic_payload = (u8 *) wpabuf_put(buf, 2 + sizeof(*ampe) +
505 if (aes_siv_encrypt(sta->aek, ampe_ie, 2 + sizeof(*ampe), 3,
506 aad, aad_len, mic_payload)) {
507 wpa_printf(MSG_ERROR, "protect frame: failed to encrypt");
520 int mesh_rsn_process_ampe(struct wpa_supplicant *wpa_s, struct sta_info *sta,
521 struct ieee802_11_elems *elems, const u8 *cat,
522 const u8 *chosen_pmk,
523 const u8 *start, size_t elems_len)
526 struct ieee80211_ampe_ie *ampe;
527 u8 null_nonce[32] = {};
530 u8 *ampe_buf, *crypt = NULL;
532 const u8 *aad[] = { sta->addr, wpa_s->own_addr, cat };
533 const size_t aad_len[] = { ETH_ALEN, ETH_ALEN,
534 (elems->mic - 2) - cat };
537 struct hostapd_data *hapd = wpa_s->ifmsh->bss[0];
539 if (!wpa_auth_pmksa_get(hapd->wpa_auth, sta->addr)) {
541 "Mesh RSN: SAE is not prepared yet");
544 mesh_rsn_auth_sae_sta(wpa_s, sta);
547 if (chosen_pmk && os_memcmp(chosen_pmk, sta->sae->pmkid, PMKID_LEN)) {
548 wpa_msg(wpa_s, MSG_DEBUG,
549 "Mesh RSN: Invalid PMKID (Chosen PMK did not match calculated PMKID)");
553 if (!elems->mic || elems->mic_len < AES_BLOCK_SIZE) {
554 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: missing mic ie");
558 ampe_buf = (u8 *) elems->mic + elems->mic_len;
559 if ((int) elems_len < ampe_buf - start)
562 crypt_len = elems_len - (elems->mic - start);
564 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: missing ampe ie");
568 /* crypt is modified by siv_decrypt */
569 crypt = os_zalloc(crypt_len);
571 wpa_printf(MSG_ERROR, "Mesh RSN: out of memory");
576 os_memcpy(crypt, elems->mic, crypt_len);
578 if (aes_siv_decrypt(sta->aek, crypt, crypt_len, 3,
579 aad, aad_len, ampe_buf)) {
580 wpa_printf(MSG_ERROR, "Mesh RSN: frame verification failed!");
585 ampe_eid = *ampe_buf++;
586 ampe_ie_len = *ampe_buf++;
588 if (ampe_eid != WLAN_EID_AMPE ||
589 ampe_ie_len < sizeof(struct ieee80211_ampe_ie)) {
590 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: invalid ampe ie");
595 ampe = (struct ieee80211_ampe_ie *) ampe_buf;
596 if (os_memcmp(ampe->peer_nonce, null_nonce, 32) != 0 &&
597 os_memcmp(ampe->peer_nonce, sta->my_nonce, 32) != 0) {
598 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: invalid peer nonce");
602 os_memcpy(sta->peer_nonce, ampe->local_nonce,
603 sizeof(ampe->local_nonce));
604 os_memcpy(sta->mgtk, ampe->mgtk, sizeof(ampe->mgtk));
606 /* todo parse mgtk expiration */