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 "wpa_supplicant_i.h"
23 #include "wpas_glue.h"
27 #define MESH_AUTH_TIMEOUT 10
28 #define MESH_AUTH_RETRY 3
30 void mesh_auth_timer(void *eloop_ctx, void *user_data)
32 struct wpa_supplicant *wpa_s = eloop_ctx;
33 struct sta_info *sta = user_data;
35 if (sta->sae->state != SAE_ACCEPTED) {
36 wpa_printf(MSG_DEBUG, "AUTH: Re-authenticate with " MACSTR
38 MAC2STR(sta->addr), sta->sae_auth_retry);
39 if (sta->sae_auth_retry < MESH_AUTH_RETRY) {
40 mesh_rsn_auth_sae_sta(wpa_s, sta);
42 /* block the STA if exceeded the number of attempts */
43 sta->plink_state = PLINK_BLOCKED;
44 sta->sae->state = SAE_NOTHING;
46 sta->sae_auth_retry++;
51 static void auth_logger(void *ctx, const u8 *addr, logger_level level,
55 wpa_printf(MSG_DEBUG, "AUTH: " MACSTR " - %s",
58 wpa_printf(MSG_DEBUG, "AUTH: %s", txt);
62 static const u8 *auth_get_psk(void *ctx, const u8 *addr,
63 const u8 *p2p_dev_addr, const u8 *prev_psk)
65 struct mesh_rsn *mesh_rsn = ctx;
66 struct hostapd_data *hapd = mesh_rsn->wpa_s->ifmsh->bss[0];
67 struct sta_info *sta = ap_get_sta(hapd, addr);
69 wpa_printf(MSG_DEBUG, "AUTH: %s (addr=" MACSTR " prev_psk=%p)",
70 __func__, MAC2STR(addr), prev_psk);
72 if (sta && sta->auth_alg == WLAN_AUTH_SAE) {
73 if (!sta->sae || prev_psk)
82 static int auth_set_key(void *ctx, int vlan_id, enum wpa_alg alg,
83 const u8 *addr, int idx, u8 *key, size_t key_len)
85 struct mesh_rsn *mesh_rsn = ctx;
88 os_memset(seq, 0, sizeof(seq));
91 wpa_printf(MSG_DEBUG, "AUTH: %s(alg=%d addr=" MACSTR
93 __func__, alg, MAC2STR(addr), idx);
95 wpa_printf(MSG_DEBUG, "AUTH: %s(alg=%d key_idx=%d)",
98 wpa_hexdump_key(MSG_DEBUG, "AUTH: set_key - key", key, key_len);
100 return wpa_drv_set_key(mesh_rsn->wpa_s, alg, addr, idx,
101 1, seq, 6, key, key_len);
105 static int auth_start_ampe(void *ctx, const u8 *addr)
107 struct mesh_rsn *mesh_rsn = ctx;
108 struct hostapd_data *hapd;
109 struct sta_info *sta;
111 if (mesh_rsn->wpa_s->current_ssid->mode != WPAS_MODE_MESH)
114 hapd = mesh_rsn->wpa_s->ifmsh->bss[0];
115 sta = ap_get_sta(hapd, addr);
117 eloop_cancel_timeout(mesh_auth_timer, mesh_rsn->wpa_s, sta);
119 mesh_mpm_auth_peer(mesh_rsn->wpa_s, addr);
124 static int __mesh_rsn_auth_init(struct mesh_rsn *rsn, const u8 *addr)
126 struct wpa_auth_config conf;
127 struct wpa_auth_callbacks cb;
130 wpa_printf(MSG_DEBUG, "AUTH: Initializing group state machine");
132 os_memset(&conf, 0, sizeof(conf));
134 conf.wpa_key_mgmt = WPA_KEY_MGMT_SAE;
135 conf.wpa_pairwise = WPA_CIPHER_CCMP;
136 conf.rsn_pairwise = WPA_CIPHER_CCMP;
137 conf.wpa_group = WPA_CIPHER_CCMP;
138 conf.eapol_version = 0;
139 conf.wpa_group_rekey = -1;
141 os_memset(&cb, 0, sizeof(cb));
143 cb.logger = auth_logger;
144 cb.get_psk = auth_get_psk;
145 cb.set_key = auth_set_key;
146 cb.start_ampe = auth_start_ampe;
148 rsn->auth = wpa_init(addr, &conf, &cb);
149 if (rsn->auth == NULL) {
150 wpa_printf(MSG_DEBUG, "AUTH: wpa_init() failed");
154 /* TODO: support rekeying */
155 if (random_get_bytes(rsn->mgtk, 16) < 0) {
156 wpa_deinit(rsn->auth);
161 wpa_drv_set_key(rsn->wpa_s, WPA_ALG_IGTK, NULL, 4, 1,
162 seq, sizeof(seq), rsn->mgtk, sizeof(rsn->mgtk));
164 /* group privacy / data frames */
165 wpa_drv_set_key(rsn->wpa_s, WPA_ALG_CCMP, NULL, 1, 1,
166 seq, sizeof(seq), rsn->mgtk, sizeof(rsn->mgtk));
172 static void mesh_rsn_deinit(struct mesh_rsn *rsn)
174 os_memset(rsn->mgtk, 0, sizeof(rsn->mgtk));
175 wpa_deinit(rsn->auth);
179 struct mesh_rsn *mesh_rsn_auth_init(struct wpa_supplicant *wpa_s,
180 struct mesh_conf *conf)
182 struct mesh_rsn *mesh_rsn;
183 struct hostapd_data *bss = wpa_s->ifmsh->bss[0];
187 mesh_rsn = os_zalloc(sizeof(*mesh_rsn));
188 if (mesh_rsn == NULL)
190 mesh_rsn->wpa_s = wpa_s;
192 if (__mesh_rsn_auth_init(mesh_rsn, wpa_s->own_addr) < 0) {
193 mesh_rsn_deinit(mesh_rsn);
197 bss->wpa_auth = mesh_rsn->auth;
199 ie = wpa_auth_get_wpa_ie(mesh_rsn->auth, &ie_len);
200 conf->ies = (u8 *) ie;
201 conf->ie_len = ie_len;
203 wpa_supplicant_rsn_supp_set_config(wpa_s, wpa_s->current_ssid);
209 static int index_within_array(const int *array, int idx)
213 for (i = 0; i < idx; i++) {
222 static int mesh_rsn_sae_group(struct wpa_supplicant *wpa_s,
223 struct sae_data *sae)
225 int *groups = wpa_s->ifmsh->bss[0]->conf->sae_groups;
227 /* Configuration may have changed, so validate current index */
228 if (!index_within_array(groups, wpa_s->mesh_rsn->sae_group_index))
232 int group = groups[wpa_s->mesh_rsn->sae_group_index];
236 if (sae_set_group(sae, group) == 0) {
237 wpa_dbg(wpa_s, MSG_DEBUG, "SME: Selected SAE group %d",
241 wpa_s->mesh_rsn->sae_group_index++;
249 mesh_rsn_build_sae_commit(struct wpa_supplicant *wpa_s,
250 struct wpa_ssid *ssid, 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 if (sae_prepare_commit(wpa_s->own_addr, sta->addr,
266 (u8 *) ssid->passphrase,
267 os_strlen(ssid->passphrase), sta->sae) < 0) {
268 wpa_msg(wpa_s, MSG_DEBUG, "SAE: Could not pick PWE");
272 len = wpa_s->mesh_rsn->sae_token ?
273 wpabuf_len(wpa_s->mesh_rsn->sae_token) : 0;
274 buf = wpabuf_alloc(4 + SAE_COMMIT_MAX_LEN + len);
278 sae_write_commit(sta->sae, buf, wpa_s->mesh_rsn->sae_token);
284 static void mesh_rsn_send_auth(struct wpa_supplicant *wpa_s,
285 const u8 *dst, const u8 *src,
286 u16 auth_transaction, u16 resp,
289 struct ieee80211_mgmt *auth;
291 size_t len, ielen = 0;
294 ielen = wpabuf_len(data);
295 len = IEEE80211_HDRLEN + sizeof(auth->u.auth) + ielen;
296 buf = os_zalloc(len);
300 auth = (struct ieee80211_mgmt *) buf;
301 auth->frame_control = IEEE80211_FC(WLAN_FC_TYPE_MGMT,
303 os_memcpy(auth->da, dst, ETH_ALEN);
304 os_memcpy(auth->sa, src, ETH_ALEN);
305 os_memcpy(auth->bssid, src, ETH_ALEN);
307 auth->u.auth.auth_alg = host_to_le16(WLAN_AUTH_SAE);
308 auth->u.auth.auth_transaction = host_to_le16(auth_transaction);
309 auth->u.auth.status_code = host_to_le16(resp);
312 os_memcpy(auth->u.auth.variable, wpabuf_head(data), ielen);
314 wpa_msg(wpa_s, MSG_DEBUG, "authentication frame: STA=" MACSTR
315 " auth_transaction=%d resp=%d (IE len=%lu)",
316 MAC2STR(dst), auth_transaction, resp, (unsigned long) ielen);
317 if (wpa_drv_send_mlme(wpa_s, buf, len, 0) < 0)
318 perror("send_auth_reply: send");
324 /* initiate new SAE authentication with sta */
325 int mesh_rsn_auth_sae_sta(struct wpa_supplicant *wpa_s,
326 struct sta_info *sta)
328 struct wpa_ssid *ssid = wpa_s->current_ssid;
333 wpa_msg(wpa_s, MSG_DEBUG,
334 "AUTH: No current_ssid known to initiate new SAE");
339 sta->sae = os_zalloc(sizeof(*sta->sae));
340 if (sta->sae == NULL)
344 buf = mesh_rsn_build_sae_commit(wpa_s, ssid, sta);
348 wpa_msg(wpa_s, MSG_DEBUG,
349 "AUTH: started authentication with SAE peer: " MACSTR,
352 sta->sae->state = SAE_COMMITTED;
353 wpa_supplicant_set_state(wpa_s, WPA_AUTHENTICATING);
355 mesh_rsn_send_auth(wpa_s, sta->addr, wpa_s->own_addr,
356 1, WLAN_STATUS_SUCCESS, buf);
358 rnd = rand() % MESH_AUTH_TIMEOUT;
359 eloop_register_timeout(MESH_AUTH_TIMEOUT + rnd, 0, mesh_auth_timer,
367 void mesh_rsn_get_pmkid(struct mesh_rsn *rsn, struct sta_info *sta, u8 *pmkid)
369 /* don't expect wpa auth to cache the pmkid for now */
370 rsn_pmkid(sta->sae->pmk, PMK_LEN, rsn->wpa_s->own_addr,
372 wpa_key_mgmt_sha256(wpa_auth_sta_key_mgmt(sta->wpa_sm)));
377 mesh_rsn_derive_aek(struct mesh_rsn *rsn, struct sta_info *sta)
379 u8 *myaddr = rsn->wpa_s->own_addr;
380 u8 *peer = sta->addr;
381 u8 *addr1 = peer, *addr2 = myaddr;
382 u8 context[AES_BLOCK_SIZE];
385 RSN_SELECTOR_PUT(context, wpa_cipher_to_suite(0, WPA_CIPHER_GCMP));
387 if (os_memcmp(myaddr, peer, ETH_ALEN) < 0) {
391 os_memcpy(context + 4, addr1, ETH_ALEN);
392 os_memcpy(context + 10, addr2, ETH_ALEN);
394 sha256_prf(sta->sae->pmk, sizeof(sta->sae->pmk), "AEK Derivation",
395 context, sizeof(context), sta->aek, sizeof(sta->aek));
399 /* derive mesh temporal key from pmk */
400 int mesh_rsn_derive_mtk(struct wpa_supplicant *wpa_s, struct sta_info *sta)
404 u16 min_lid, max_lid;
405 size_t nonce_len = sizeof(sta->my_nonce);
406 size_t lid_len = sizeof(sta->my_lid);
407 u8 *myaddr = wpa_s->own_addr;
408 u8 *peer = sta->addr;
409 /* 2 nonces, 2 linkids, akm suite, 2 mac addrs */
410 u8 context[64 + 4 + 4 + 12];
413 if (os_memcmp(sta->my_nonce, sta->peer_nonce, nonce_len) < 0) {
415 max = sta->peer_nonce;
417 min = sta->peer_nonce;
420 os_memcpy(ptr, min, nonce_len);
421 os_memcpy(ptr + nonce_len, max, nonce_len);
422 ptr += 2 * nonce_len;
424 if (sta->my_lid < sta->peer_lid) {
425 min_lid = host_to_le16(sta->my_lid);
426 max_lid = host_to_le16(sta->peer_lid);
428 min_lid = host_to_le16(sta->peer_lid);
429 max_lid = host_to_le16(sta->my_lid);
431 os_memcpy(ptr, &min_lid, lid_len);
432 os_memcpy(ptr + lid_len, &max_lid, lid_len);
436 RSN_SELECTOR_PUT(ptr, wpa_cipher_to_suite(0, WPA_CIPHER_GCMP));
439 if (os_memcmp(myaddr, peer, ETH_ALEN) < 0) {
446 os_memcpy(ptr, min, ETH_ALEN);
447 os_memcpy(ptr + ETH_ALEN, max, ETH_ALEN);
449 sha256_prf(sta->sae->pmk, sizeof(sta->sae->pmk),
450 "Temporal Key Derivation", context, sizeof(context),
451 sta->mtk, sizeof(sta->mtk));
456 void mesh_rsn_init_ampe_sta(struct wpa_supplicant *wpa_s, struct sta_info *sta)
458 if (random_get_bytes(sta->my_nonce, 32) < 0) {
459 wpa_printf(MSG_INFO, "mesh: Failed to derive random nonce");
460 /* TODO: How to handle this more cleanly? */
462 os_memset(sta->peer_nonce, 0, 32);
463 mesh_rsn_derive_aek(wpa_s->mesh_rsn, sta);
467 /* insert AMPE and encrypted MIC at @ie.
468 * @mesh_rsn: mesh RSN context
469 * @sta: STA we're sending to
470 * @cat: pointer to category code in frame header.
471 * @buf: wpabuf to add encrypted AMPE and MIC to.
473 int mesh_rsn_protect_frame(struct mesh_rsn *rsn, struct sta_info *sta,
474 const u8 *cat, struct wpabuf *buf)
476 struct ieee80211_ampe_ie *ampe;
477 u8 const *ie = wpabuf_head_u8(buf) + wpabuf_len(buf);
478 u8 *ampe_ie = NULL, *mic_ie = NULL, *mic_payload;
479 const u8 *aad[] = { rsn->wpa_s->own_addr, sta->addr, cat };
480 const size_t aad_len[] = { ETH_ALEN, ETH_ALEN, ie - cat };
483 if (AES_BLOCK_SIZE + 2 + sizeof(*ampe) + 2 > wpabuf_tailroom(buf)) {
484 wpa_printf(MSG_ERROR, "protect frame: buffer too small");
488 ampe_ie = os_zalloc(2 + sizeof(*ampe));
490 wpa_printf(MSG_ERROR, "protect frame: out of memory");
494 mic_ie = os_zalloc(2 + AES_BLOCK_SIZE);
496 wpa_printf(MSG_ERROR, "protect frame: out of memory");
502 ampe_ie[0] = WLAN_EID_AMPE;
503 ampe_ie[1] = sizeof(*ampe);
504 ampe = (struct ieee80211_ampe_ie *) (ampe_ie + 2);
506 RSN_SELECTOR_PUT(ampe->selected_pairwise_suite,
507 wpa_cipher_to_suite(WPA_PROTO_RSN, WPA_CIPHER_CCMP));
508 os_memcpy(ampe->local_nonce, sta->my_nonce, 32);
509 os_memcpy(ampe->peer_nonce, sta->peer_nonce, 32);
510 /* incomplete: see 13.5.4 */
511 /* TODO: static mgtk for now since we don't support rekeying! */
512 os_memcpy(ampe->mgtk, rsn->mgtk, 16);
513 /* TODO: Populate Key RSC */
514 /* expire in 13 decades or so */
515 os_memset(ampe->key_expiration, 0xff, 4);
518 mic_ie[0] = WLAN_EID_MIC;
519 mic_ie[1] = AES_BLOCK_SIZE;
520 wpabuf_put_data(buf, mic_ie, 2);
521 /* MIC field is output ciphertext */
523 /* encrypt after MIC */
524 mic_payload = (u8 *) wpabuf_put(buf, 2 + sizeof(*ampe) +
527 if (aes_siv_encrypt(sta->aek, ampe_ie, 2 + sizeof(*ampe), 3,
528 aad, aad_len, mic_payload)) {
529 wpa_printf(MSG_ERROR, "protect frame: failed to encrypt");
542 int mesh_rsn_process_ampe(struct wpa_supplicant *wpa_s, struct sta_info *sta,
543 struct ieee802_11_elems *elems, const u8 *cat,
544 const u8 *start, size_t elems_len)
547 struct ieee80211_ampe_ie *ampe;
548 u8 null_nonce[32] = {};
551 u8 *ampe_buf, *crypt = NULL;
553 const u8 *aad[] = { sta->addr, wpa_s->own_addr, cat };
554 const size_t aad_len[] = { ETH_ALEN, ETH_ALEN,
555 (elems->mic - 2) - cat };
557 if (!elems->mic || elems->mic_len < AES_BLOCK_SIZE) {
558 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: missing mic ie");
562 ampe_buf = (u8 *) elems->mic + elems->mic_len;
563 if ((int) elems_len < ampe_buf - start)
566 crypt_len = elems_len - (elems->mic - start);
568 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: missing ampe ie");
572 /* crypt is modified by siv_decrypt */
573 crypt = os_zalloc(crypt_len);
575 wpa_printf(MSG_ERROR, "Mesh RSN: out of memory");
580 os_memcpy(crypt, elems->mic, crypt_len);
582 if (aes_siv_decrypt(sta->aek, crypt, crypt_len, 3,
583 aad, aad_len, ampe_buf)) {
584 wpa_printf(MSG_ERROR, "Mesh RSN: frame verification failed!");
589 ampe_eid = *ampe_buf++;
590 ampe_ie_len = *ampe_buf++;
592 if (ampe_eid != WLAN_EID_AMPE ||
593 ampe_ie_len < sizeof(struct ieee80211_ampe_ie)) {
594 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: invalid ampe ie");
599 ampe = (struct ieee80211_ampe_ie *) ampe_buf;
600 if (os_memcmp(ampe->peer_nonce, null_nonce, 32) != 0 &&
601 os_memcmp(ampe->peer_nonce, sta->my_nonce, 32) != 0) {
602 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: invalid peer nonce");
606 os_memcpy(sta->peer_nonce, ampe->local_nonce,
607 sizeof(ampe->local_nonce));
608 os_memcpy(sta->mgtk, ampe->mgtk, sizeof(ampe->mgtk));
610 /* todo parse mgtk expiration */