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 if (sta->sae_auth_retry < MESH_AUTH_RETRY) {
41 mesh_rsn_auth_sae_sta(wpa_s, sta);
43 /* block the STA if exceeded the number of attempts */
44 sta->plink_state = PLINK_BLOCKED;
45 sta->sae->state = SAE_NOTHING;
47 sta->sae_auth_retry++;
52 static void auth_logger(void *ctx, const u8 *addr, logger_level level,
56 wpa_printf(MSG_DEBUG, "AUTH: " MACSTR " - %s",
59 wpa_printf(MSG_DEBUG, "AUTH: %s", txt);
63 static const u8 *auth_get_psk(void *ctx, const u8 *addr,
64 const u8 *p2p_dev_addr, const u8 *prev_psk)
66 struct mesh_rsn *mesh_rsn = ctx;
67 struct hostapd_data *hapd = mesh_rsn->wpa_s->ifmsh->bss[0];
68 struct sta_info *sta = ap_get_sta(hapd, addr);
70 wpa_printf(MSG_DEBUG, "AUTH: %s (addr=" MACSTR " prev_psk=%p)",
71 __func__, MAC2STR(addr), prev_psk);
73 if (sta && sta->auth_alg == WLAN_AUTH_SAE) {
74 if (!sta->sae || prev_psk)
83 static int auth_set_key(void *ctx, int vlan_id, enum wpa_alg alg,
84 const u8 *addr, int idx, u8 *key, size_t key_len)
86 struct mesh_rsn *mesh_rsn = ctx;
89 os_memset(seq, 0, sizeof(seq));
92 wpa_printf(MSG_DEBUG, "AUTH: %s(alg=%d addr=" MACSTR
94 __func__, alg, MAC2STR(addr), idx);
96 wpa_printf(MSG_DEBUG, "AUTH: %s(alg=%d key_idx=%d)",
99 wpa_hexdump_key(MSG_DEBUG, "AUTH: set_key - key", key, key_len);
101 return wpa_drv_set_key(mesh_rsn->wpa_s, alg, addr, idx,
102 1, seq, 6, key, key_len);
106 static int auth_start_ampe(void *ctx, const u8 *addr)
108 struct mesh_rsn *mesh_rsn = ctx;
109 struct hostapd_data *hapd;
110 struct sta_info *sta;
112 if (mesh_rsn->wpa_s->current_ssid->mode != WPAS_MODE_MESH)
115 hapd = mesh_rsn->wpa_s->ifmsh->bss[0];
116 sta = ap_get_sta(hapd, addr);
118 eloop_cancel_timeout(mesh_auth_timer, mesh_rsn->wpa_s, sta);
120 mesh_mpm_auth_peer(mesh_rsn->wpa_s, addr);
125 static int __mesh_rsn_auth_init(struct mesh_rsn *rsn, const u8 *addr)
127 struct wpa_auth_config conf;
128 struct wpa_auth_callbacks cb;
131 wpa_printf(MSG_DEBUG, "AUTH: Initializing group state machine");
133 os_memset(&conf, 0, sizeof(conf));
135 conf.wpa_key_mgmt = WPA_KEY_MGMT_SAE;
136 conf.wpa_pairwise = WPA_CIPHER_CCMP;
137 conf.rsn_pairwise = WPA_CIPHER_CCMP;
138 conf.wpa_group = WPA_CIPHER_CCMP;
139 conf.eapol_version = 0;
140 conf.wpa_group_rekey = -1;
142 os_memset(&cb, 0, sizeof(cb));
144 cb.logger = auth_logger;
145 cb.get_psk = auth_get_psk;
146 cb.set_key = auth_set_key;
147 cb.start_ampe = auth_start_ampe;
149 rsn->auth = wpa_init(addr, &conf, &cb);
150 if (rsn->auth == NULL) {
151 wpa_printf(MSG_DEBUG, "AUTH: wpa_init() failed");
155 /* TODO: support rekeying */
156 if (random_get_bytes(rsn->mgtk, 16) < 0) {
157 wpa_deinit(rsn->auth);
162 wpa_drv_set_key(rsn->wpa_s, WPA_ALG_IGTK, NULL, 4, 1,
163 seq, sizeof(seq), rsn->mgtk, sizeof(rsn->mgtk));
165 /* group privacy / data frames */
166 wpa_drv_set_key(rsn->wpa_s, WPA_ALG_CCMP, NULL, 1, 1,
167 seq, sizeof(seq), rsn->mgtk, sizeof(rsn->mgtk));
173 static void mesh_rsn_deinit(struct mesh_rsn *rsn)
175 os_memset(rsn->mgtk, 0, sizeof(rsn->mgtk));
176 wpa_deinit(rsn->auth);
180 struct mesh_rsn *mesh_rsn_auth_init(struct wpa_supplicant *wpa_s,
181 struct mesh_conf *conf)
183 struct mesh_rsn *mesh_rsn;
184 struct hostapd_data *bss = wpa_s->ifmsh->bss[0];
188 mesh_rsn = os_zalloc(sizeof(*mesh_rsn));
189 if (mesh_rsn == NULL)
191 mesh_rsn->wpa_s = wpa_s;
193 if (__mesh_rsn_auth_init(mesh_rsn, wpa_s->own_addr) < 0) {
194 mesh_rsn_deinit(mesh_rsn);
198 bss->wpa_auth = mesh_rsn->auth;
200 ie = wpa_auth_get_wpa_ie(mesh_rsn->auth, &ie_len);
201 conf->ies = (u8 *) ie;
202 conf->ie_len = ie_len;
204 wpa_supplicant_rsn_supp_set_config(wpa_s, wpa_s->current_ssid);
210 static int index_within_array(const int *array, int idx)
214 for (i = 0; i < idx; i++) {
223 static int mesh_rsn_sae_group(struct wpa_supplicant *wpa_s,
224 struct sae_data *sae)
226 int *groups = wpa_s->ifmsh->bss[0]->conf->sae_groups;
228 /* Configuration may have changed, so validate current index */
229 if (!index_within_array(groups, wpa_s->mesh_rsn->sae_group_index))
233 int group = groups[wpa_s->mesh_rsn->sae_group_index];
237 if (sae_set_group(sae, group) == 0) {
238 wpa_dbg(wpa_s, MSG_DEBUG, "SME: Selected SAE group %d",
242 wpa_s->mesh_rsn->sae_group_index++;
249 static int mesh_rsn_build_sae_commit(struct wpa_supplicant *wpa_s,
250 struct wpa_ssid *ssid,
251 struct sta_info *sta)
253 if (ssid->passphrase == NULL) {
254 wpa_msg(wpa_s, MSG_DEBUG, "SAE: No password available");
258 if (mesh_rsn_sae_group(wpa_s, sta->sae) < 0) {
259 wpa_msg(wpa_s, MSG_DEBUG, "SAE: Failed to select group");
263 return sae_prepare_commit(wpa_s->own_addr, sta->addr,
264 (u8 *) ssid->passphrase,
265 os_strlen(ssid->passphrase), sta->sae);
269 /* initiate new SAE authentication with sta */
270 int mesh_rsn_auth_sae_sta(struct wpa_supplicant *wpa_s,
271 struct sta_info *sta)
273 struct hostapd_data *hapd = wpa_s->ifmsh->bss[0];
274 struct wpa_ssid *ssid = wpa_s->current_ssid;
279 wpa_msg(wpa_s, MSG_DEBUG,
280 "AUTH: No current_ssid known to initiate new SAE");
285 sta->sae = os_zalloc(sizeof(*sta->sae));
286 if (sta->sae == NULL)
290 if (mesh_rsn_build_sae_commit(wpa_s, ssid, sta))
293 wpa_msg(wpa_s, MSG_DEBUG,
294 "AUTH: started authentication with SAE peer: " MACSTR,
297 wpa_supplicant_set_state(wpa_s, WPA_AUTHENTICATING);
298 ret = auth_sae_init_committed(hapd, sta);
302 rnd = rand() % MESH_AUTH_TIMEOUT;
303 eloop_register_timeout(MESH_AUTH_TIMEOUT + rnd, 0, mesh_auth_timer,
309 void mesh_rsn_get_pmkid(struct mesh_rsn *rsn, struct sta_info *sta, u8 *pmkid)
311 /* don't expect wpa auth to cache the pmkid for now */
312 rsn_pmkid(sta->sae->pmk, PMK_LEN, rsn->wpa_s->own_addr,
314 wpa_key_mgmt_sha256(wpa_auth_sta_key_mgmt(sta->wpa_sm)));
319 mesh_rsn_derive_aek(struct mesh_rsn *rsn, struct sta_info *sta)
321 u8 *myaddr = rsn->wpa_s->own_addr;
322 u8 *peer = sta->addr;
323 u8 *addr1 = peer, *addr2 = myaddr;
324 u8 context[AES_BLOCK_SIZE];
327 RSN_SELECTOR_PUT(context, wpa_cipher_to_suite(0, WPA_CIPHER_GCMP));
329 if (os_memcmp(myaddr, peer, ETH_ALEN) < 0) {
333 os_memcpy(context + 4, addr1, ETH_ALEN);
334 os_memcpy(context + 10, addr2, ETH_ALEN);
336 sha256_prf(sta->sae->pmk, sizeof(sta->sae->pmk), "AEK Derivation",
337 context, sizeof(context), sta->aek, sizeof(sta->aek));
341 /* derive mesh temporal key from pmk */
342 int mesh_rsn_derive_mtk(struct wpa_supplicant *wpa_s, struct sta_info *sta)
346 u16 min_lid, max_lid;
347 size_t nonce_len = sizeof(sta->my_nonce);
348 size_t lid_len = sizeof(sta->my_lid);
349 u8 *myaddr = wpa_s->own_addr;
350 u8 *peer = sta->addr;
351 /* 2 nonces, 2 linkids, akm suite, 2 mac addrs */
352 u8 context[64 + 4 + 4 + 12];
355 if (os_memcmp(sta->my_nonce, sta->peer_nonce, nonce_len) < 0) {
357 max = sta->peer_nonce;
359 min = sta->peer_nonce;
362 os_memcpy(ptr, min, nonce_len);
363 os_memcpy(ptr + nonce_len, max, nonce_len);
364 ptr += 2 * nonce_len;
366 if (sta->my_lid < sta->peer_lid) {
367 min_lid = host_to_le16(sta->my_lid);
368 max_lid = host_to_le16(sta->peer_lid);
370 min_lid = host_to_le16(sta->peer_lid);
371 max_lid = host_to_le16(sta->my_lid);
373 os_memcpy(ptr, &min_lid, lid_len);
374 os_memcpy(ptr + lid_len, &max_lid, lid_len);
378 RSN_SELECTOR_PUT(ptr, wpa_cipher_to_suite(0, WPA_CIPHER_GCMP));
381 if (os_memcmp(myaddr, peer, ETH_ALEN) < 0) {
388 os_memcpy(ptr, min, ETH_ALEN);
389 os_memcpy(ptr + ETH_ALEN, max, ETH_ALEN);
391 sha256_prf(sta->sae->pmk, sizeof(sta->sae->pmk),
392 "Temporal Key Derivation", context, sizeof(context),
393 sta->mtk, sizeof(sta->mtk));
398 void mesh_rsn_init_ampe_sta(struct wpa_supplicant *wpa_s, struct sta_info *sta)
400 if (random_get_bytes(sta->my_nonce, 32) < 0) {
401 wpa_printf(MSG_INFO, "mesh: Failed to derive random nonce");
402 /* TODO: How to handle this more cleanly? */
404 os_memset(sta->peer_nonce, 0, 32);
405 mesh_rsn_derive_aek(wpa_s->mesh_rsn, sta);
409 /* insert AMPE and encrypted MIC at @ie.
410 * @mesh_rsn: mesh RSN context
411 * @sta: STA we're sending to
412 * @cat: pointer to category code in frame header.
413 * @buf: wpabuf to add encrypted AMPE and MIC to.
415 int mesh_rsn_protect_frame(struct mesh_rsn *rsn, struct sta_info *sta,
416 const u8 *cat, struct wpabuf *buf)
418 struct ieee80211_ampe_ie *ampe;
419 u8 const *ie = wpabuf_head_u8(buf) + wpabuf_len(buf);
420 u8 *ampe_ie = NULL, *mic_ie = NULL, *mic_payload;
421 const u8 *aad[] = { rsn->wpa_s->own_addr, sta->addr, cat };
422 const size_t aad_len[] = { ETH_ALEN, ETH_ALEN, ie - cat };
425 if (AES_BLOCK_SIZE + 2 + sizeof(*ampe) + 2 > wpabuf_tailroom(buf)) {
426 wpa_printf(MSG_ERROR, "protect frame: buffer too small");
430 ampe_ie = os_zalloc(2 + sizeof(*ampe));
432 wpa_printf(MSG_ERROR, "protect frame: out of memory");
436 mic_ie = os_zalloc(2 + AES_BLOCK_SIZE);
438 wpa_printf(MSG_ERROR, "protect frame: out of memory");
444 ampe_ie[0] = WLAN_EID_AMPE;
445 ampe_ie[1] = sizeof(*ampe);
446 ampe = (struct ieee80211_ampe_ie *) (ampe_ie + 2);
448 RSN_SELECTOR_PUT(ampe->selected_pairwise_suite,
449 wpa_cipher_to_suite(WPA_PROTO_RSN, WPA_CIPHER_CCMP));
450 os_memcpy(ampe->local_nonce, sta->my_nonce, 32);
451 os_memcpy(ampe->peer_nonce, sta->peer_nonce, 32);
452 /* incomplete: see 13.5.4 */
453 /* TODO: static mgtk for now since we don't support rekeying! */
454 os_memcpy(ampe->mgtk, rsn->mgtk, 16);
455 /* TODO: Populate Key RSC */
456 /* expire in 13 decades or so */
457 os_memset(ampe->key_expiration, 0xff, 4);
460 mic_ie[0] = WLAN_EID_MIC;
461 mic_ie[1] = AES_BLOCK_SIZE;
462 wpabuf_put_data(buf, mic_ie, 2);
463 /* MIC field is output ciphertext */
465 /* encrypt after MIC */
466 mic_payload = (u8 *) wpabuf_put(buf, 2 + sizeof(*ampe) +
469 if (aes_siv_encrypt(sta->aek, ampe_ie, 2 + sizeof(*ampe), 3,
470 aad, aad_len, mic_payload)) {
471 wpa_printf(MSG_ERROR, "protect frame: failed to encrypt");
484 int mesh_rsn_process_ampe(struct wpa_supplicant *wpa_s, struct sta_info *sta,
485 struct ieee802_11_elems *elems, const u8 *cat,
486 const u8 *start, size_t elems_len)
489 struct ieee80211_ampe_ie *ampe;
490 u8 null_nonce[32] = {};
493 u8 *ampe_buf, *crypt = NULL;
495 const u8 *aad[] = { sta->addr, wpa_s->own_addr, cat };
496 const size_t aad_len[] = { ETH_ALEN, ETH_ALEN,
497 (elems->mic - 2) - cat };
499 if (!elems->mic || elems->mic_len < AES_BLOCK_SIZE) {
500 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: missing mic ie");
504 ampe_buf = (u8 *) elems->mic + elems->mic_len;
505 if ((int) elems_len < ampe_buf - start)
508 crypt_len = elems_len - (elems->mic - start);
510 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: missing ampe ie");
514 /* crypt is modified by siv_decrypt */
515 crypt = os_zalloc(crypt_len);
517 wpa_printf(MSG_ERROR, "Mesh RSN: out of memory");
522 os_memcpy(crypt, elems->mic, crypt_len);
524 if (aes_siv_decrypt(sta->aek, crypt, crypt_len, 3,
525 aad, aad_len, ampe_buf)) {
526 wpa_printf(MSG_ERROR, "Mesh RSN: frame verification failed!");
531 ampe_eid = *ampe_buf++;
532 ampe_ie_len = *ampe_buf++;
534 if (ampe_eid != WLAN_EID_AMPE ||
535 ampe_ie_len < sizeof(struct ieee80211_ampe_ie)) {
536 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: invalid ampe ie");
541 ampe = (struct ieee80211_ampe_ie *) ampe_buf;
542 if (os_memcmp(ampe->peer_nonce, null_nonce, 32) != 0 &&
543 os_memcmp(ampe->peer_nonce, sta->my_nonce, 32) != 0) {
544 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: invalid peer nonce");
548 os_memcpy(sta->peer_nonce, ampe->local_nonce,
549 sizeof(ampe->local_nonce));
550 os_memcpy(sta->mgtk, ampe->mgtk, sizeof(ampe->mgtk));
552 /* todo parse mgtk expiration */