1 /*
2 * WPA Supplicant - Mesh RSN routines
3 * Copyright (c) 2013-2014, cozybit, Inc. All rights reserved.
4 *
5 * This software may be distributed under the terms of the BSD license.
6 * See README for more details.
7 */
8
9 #include "utils/includes.h"
10
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"
23 #include "driver_i.h"
24 #include "wpas_glue.h"
25 #include "mesh_mpm.h"
26 #include "mesh_rsn.h"
27
28 #define MESH_AUTH_TIMEOUT 10
29 #define MESH_AUTH_RETRY 3
30
mesh_auth_timer(void * eloop_ctx,void * user_data)31 void mesh_auth_timer(void *eloop_ctx, void *user_data)
32 {
33 struct wpa_supplicant *wpa_s = eloop_ctx;
34 struct sta_info *sta = user_data;
35 struct hostapd_data *hapd;
36
37 if (sta->sae->state != SAE_ACCEPTED) {
38 wpa_printf(MSG_DEBUG, "AUTH: Re-authenticate with " MACSTR
39 " (attempt %d) ",
40 MAC2STR(sta->addr), sta->sae_auth_retry);
41 wpa_msg(wpa_s, MSG_INFO, MESH_SAE_AUTH_FAILURE "addr=" MACSTR,
42 MAC2STR(sta->addr));
43 if (sta->sae_auth_retry < MESH_AUTH_RETRY) {
44 mesh_rsn_auth_sae_sta(wpa_s, sta);
45 } else {
46 hapd = wpa_s->ifmsh->bss[0];
47
48 if (sta->sae_auth_retry > MESH_AUTH_RETRY) {
49 ap_free_sta(hapd, sta);
50 return;
51 }
52
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",
58 MAC2STR(sta->addr),
59 hapd->conf->ap_max_inactivity);
60 }
61 sta->sae_auth_retry++;
62 }
63 }
64
65
auth_logger(void * ctx,const u8 * addr,logger_level level,const char * txt)66 static void auth_logger(void *ctx, const u8 *addr, logger_level level,
67 const char *txt)
68 {
69 if (addr)
70 wpa_printf(MSG_DEBUG, "AUTH: " MACSTR " - %s",
71 MAC2STR(addr), txt);
72 else
73 wpa_printf(MSG_DEBUG, "AUTH: %s", txt);
74 }
75
76
auth_get_psk(void * ctx,const u8 * addr,const u8 * p2p_dev_addr,const u8 * prev_psk,size_t * psk_len,int * vlan_id)77 static const u8 *auth_get_psk(void *ctx, const u8 *addr,
78 const u8 *p2p_dev_addr, const u8 *prev_psk,
79 size_t *psk_len, int *vlan_id)
80 {
81 struct mesh_rsn *mesh_rsn = ctx;
82 struct hostapd_data *hapd = mesh_rsn->wpa_s->ifmsh->bss[0];
83 struct sta_info *sta = ap_get_sta(hapd, addr);
84
85 if (psk_len)
86 *psk_len = PMK_LEN;
87 if (vlan_id)
88 *vlan_id = 0;
89 wpa_printf(MSG_DEBUG, "AUTH: %s (addr=" MACSTR " prev_psk=%p)",
90 __func__, MAC2STR(addr), prev_psk);
91
92 if (sta && sta->auth_alg == WLAN_AUTH_SAE) {
93 if (!sta->sae || prev_psk)
94 return NULL;
95 return sta->sae->pmk;
96 }
97
98 return NULL;
99 }
100
101
auth_set_key(void * ctx,int vlan_id,enum wpa_alg alg,const u8 * addr,int idx,u8 * key,size_t key_len,enum key_flag key_flag)102 static int auth_set_key(void *ctx, int vlan_id, enum wpa_alg alg,
103 const u8 *addr, int idx, u8 *key, size_t key_len,
104 enum key_flag key_flag)
105 {
106 struct mesh_rsn *mesh_rsn = ctx;
107 u8 seq[6];
108
109 os_memset(seq, 0, sizeof(seq));
110
111 if (addr) {
112 wpa_printf(MSG_DEBUG, "AUTH: %s(alg=%d addr=" MACSTR
113 " key_idx=%d)",
114 __func__, alg, MAC2STR(addr), idx);
115 } else {
116 wpa_printf(MSG_DEBUG, "AUTH: %s(alg=%d key_idx=%d)",
117 __func__, alg, idx);
118 }
119 wpa_hexdump_key(MSG_DEBUG, "AUTH: set_key - key", key, key_len);
120
121 return wpa_drv_set_key(mesh_rsn->wpa_s, alg, addr, idx,
122 1, seq, 6, key, key_len, key_flag);
123 }
124
125
auth_start_ampe(void * ctx,const u8 * addr)126 static int auth_start_ampe(void *ctx, const u8 *addr)
127 {
128 struct mesh_rsn *mesh_rsn = ctx;
129 struct hostapd_data *hapd;
130 struct sta_info *sta;
131
132 if (mesh_rsn->wpa_s->current_ssid->mode != WPAS_MODE_MESH)
133 return -1;
134
135 hapd = mesh_rsn->wpa_s->ifmsh->bss[0];
136 sta = ap_get_sta(hapd, addr);
137 if (sta)
138 eloop_cancel_timeout(mesh_auth_timer, mesh_rsn->wpa_s, sta);
139
140 mesh_mpm_auth_peer(mesh_rsn->wpa_s, addr);
141 return 0;
142 }
143
144
__mesh_rsn_auth_init(struct mesh_rsn * rsn,const u8 * addr,enum mfp_options ieee80211w,int ocv)145 static int __mesh_rsn_auth_init(struct mesh_rsn *rsn, const u8 *addr,
146 enum mfp_options ieee80211w, int ocv)
147 {
148 struct wpa_auth_config conf;
149 static const struct wpa_auth_callbacks cb = {
150 .logger = auth_logger,
151 .get_psk = auth_get_psk,
152 .set_key = auth_set_key,
153 .start_ampe = auth_start_ampe,
154 };
155 u8 seq[6] = {};
156
157 wpa_printf(MSG_DEBUG, "AUTH: Initializing group state machine");
158
159 os_memset(&conf, 0, sizeof(conf));
160 conf.wpa = WPA_PROTO_RSN;
161 conf.wpa_key_mgmt = WPA_KEY_MGMT_SAE;
162 conf.wpa_pairwise = rsn->pairwise_cipher;
163 conf.rsn_pairwise = rsn->pairwise_cipher;
164 conf.wpa_group = rsn->group_cipher;
165 conf.eapol_version = 0;
166 conf.wpa_group_rekey = -1;
167 conf.wpa_group_update_count = 4;
168 conf.wpa_pairwise_update_count = 4;
169 conf.ieee80211w = ieee80211w;
170 if (ieee80211w != NO_MGMT_FRAME_PROTECTION)
171 conf.group_mgmt_cipher = rsn->mgmt_group_cipher;
172 #ifdef CONFIG_OCV
173 conf.ocv = ocv;
174 #endif /* CONFIG_OCV */
175
176 rsn->auth = wpa_init(addr, &conf, &cb, rsn);
177 if (rsn->auth == NULL) {
178 wpa_printf(MSG_DEBUG, "AUTH: wpa_init() failed");
179 return -1;
180 }
181
182 /* TODO: support rekeying */
183 rsn->mgtk_len = wpa_cipher_key_len(conf.wpa_group);
184 if (random_get_bytes(rsn->mgtk, rsn->mgtk_len) < 0)
185 return -1;
186 rsn->mgtk_key_id = 1;
187
188 if (ieee80211w != NO_MGMT_FRAME_PROTECTION) {
189 rsn->igtk_len = wpa_cipher_key_len(conf.group_mgmt_cipher);
190 if (random_get_bytes(rsn->igtk, rsn->igtk_len) < 0)
191 return -1;
192 rsn->igtk_key_id = 4;
193
194 /* group mgmt */
195 wpa_hexdump_key(MSG_DEBUG, "mesh: Own TX IGTK",
196 rsn->igtk, rsn->igtk_len);
197 wpa_drv_set_key(rsn->wpa_s,
198 wpa_cipher_to_alg(rsn->mgmt_group_cipher),
199 broadcast_ether_addr,
200 rsn->igtk_key_id, 1,
201 seq, sizeof(seq), rsn->igtk, rsn->igtk_len,
202 KEY_FLAG_GROUP_TX_DEFAULT);
203 }
204
205 /* group privacy / data frames */
206 wpa_hexdump_key(MSG_DEBUG, "mesh: Own TX MGTK",
207 rsn->mgtk, rsn->mgtk_len);
208 wpa_drv_set_key(rsn->wpa_s, wpa_cipher_to_alg(rsn->group_cipher),
209 broadcast_ether_addr,
210 rsn->mgtk_key_id, 1, seq, sizeof(seq),
211 rsn->mgtk, rsn->mgtk_len, KEY_FLAG_GROUP_TX_DEFAULT);
212
213 return 0;
214 }
215
216
mesh_rsn_deinit(struct mesh_rsn * rsn)217 static void mesh_rsn_deinit(struct mesh_rsn *rsn)
218 {
219 os_memset(rsn->mgtk, 0, sizeof(rsn->mgtk));
220 rsn->mgtk_len = 0;
221 os_memset(rsn->igtk, 0, sizeof(rsn->igtk));
222 rsn->igtk_len = 0;
223 if (rsn->auth)
224 wpa_deinit(rsn->auth);
225 }
226
227
mesh_rsn_auth_init(struct wpa_supplicant * wpa_s,struct mesh_conf * conf)228 struct mesh_rsn *mesh_rsn_auth_init(struct wpa_supplicant *wpa_s,
229 struct mesh_conf *conf)
230 {
231 struct mesh_rsn *mesh_rsn;
232 struct hostapd_data *bss = wpa_s->ifmsh->bss[0];
233 const u8 *ie;
234 size_t ie_len;
235 #ifdef CONFIG_PMKSA_CACHE_EXTERNAL
236 struct external_pmksa_cache *entry;
237 #endif /* CONFIG_PMKSA_CACHE_EXTERNAL */
238
239 mesh_rsn = os_zalloc(sizeof(*mesh_rsn));
240 if (mesh_rsn == NULL)
241 return NULL;
242 mesh_rsn->wpa_s = wpa_s;
243 mesh_rsn->pairwise_cipher = conf->pairwise_cipher;
244 mesh_rsn->group_cipher = conf->group_cipher;
245 mesh_rsn->mgmt_group_cipher = conf->mgmt_group_cipher;
246
247 if (__mesh_rsn_auth_init(mesh_rsn, wpa_s->own_addr,
248 conf->ieee80211w, conf->ocv) < 0) {
249 mesh_rsn_deinit(mesh_rsn);
250 os_free(mesh_rsn);
251 return NULL;
252 }
253
254 bss->wpa_auth = mesh_rsn->auth;
255
256 #ifdef CONFIG_PMKSA_CACHE_EXTERNAL
257 while ((entry = dl_list_last(&wpa_s->mesh_external_pmksa_cache,
258 struct external_pmksa_cache,
259 list)) != NULL) {
260 int ret;
261
262 ret = wpa_auth_pmksa_add_entry(bss->wpa_auth,
263 entry->pmksa_cache);
264 dl_list_del(&entry->list);
265 os_free(entry);
266
267 if (ret < 0)
268 return NULL;
269 }
270 #endif /* CONFIG_PMKSA_CACHE_EXTERNAL */
271
272 ie = wpa_auth_get_wpa_ie(mesh_rsn->auth, &ie_len);
273 conf->rsn_ie = (u8 *) ie;
274 conf->rsn_ie_len = ie_len;
275
276 wpa_supplicant_rsn_supp_set_config(wpa_s, wpa_s->current_ssid);
277
278 return mesh_rsn;
279 }
280
281
index_within_array(const int * array,int idx)282 static int index_within_array(const int *array, int idx)
283 {
284 int i;
285
286 for (i = 0; i < idx; i++) {
287 if (array[i] == -1)
288 return 0;
289 }
290
291 return 1;
292 }
293
294
mesh_rsn_sae_group(struct wpa_supplicant * wpa_s,struct sae_data * sae)295 static int mesh_rsn_sae_group(struct wpa_supplicant *wpa_s,
296 struct sae_data *sae)
297 {
298 int *groups = wpa_s->ifmsh->bss[0]->conf->sae_groups;
299
300 /* Configuration may have changed, so validate current index */
301 if (!index_within_array(groups, wpa_s->mesh_rsn->sae_group_index))
302 return -1;
303
304 for (;;) {
305 int group = groups[wpa_s->mesh_rsn->sae_group_index];
306
307 if (group <= 0)
308 break;
309 if (sae_set_group(sae, group) == 0) {
310 wpa_dbg(wpa_s, MSG_DEBUG, "SME: Selected SAE group %d",
311 sae->group);
312 return 0;
313 }
314 wpa_s->mesh_rsn->sae_group_index++;
315 }
316
317 return -1;
318 }
319
320
mesh_rsn_build_sae_commit(struct wpa_supplicant * wpa_s,struct wpa_ssid * ssid,struct sta_info * sta)321 static int mesh_rsn_build_sae_commit(struct wpa_supplicant *wpa_s,
322 struct wpa_ssid *ssid,
323 struct sta_info *sta)
324 {
325 const char *password;
326
327 password = ssid->sae_password;
328 if (!password)
329 password = ssid->passphrase;
330 if (!password) {
331 wpa_msg(wpa_s, MSG_DEBUG, "SAE: No password available");
332 return -1;
333 }
334
335 if (mesh_rsn_sae_group(wpa_s, sta->sae) < 0) {
336 wpa_msg(wpa_s, MSG_DEBUG, "SAE: Failed to select group");
337 return -1;
338 }
339
340 if (sta->sae->tmp && !sta->sae->tmp->pw_id && ssid->sae_password_id) {
341 sta->sae->tmp->pw_id = os_strdup(ssid->sae_password_id);
342 if (!sta->sae->tmp->pw_id)
343 return -1;
344 }
345 return sae_prepare_commit(wpa_s->own_addr, sta->addr,
346 (u8 *) password, os_strlen(password),
347 sta->sae);
348 }
349
350
351 /* initiate new SAE authentication with sta */
mesh_rsn_auth_sae_sta(struct wpa_supplicant * wpa_s,struct sta_info * sta)352 int mesh_rsn_auth_sae_sta(struct wpa_supplicant *wpa_s,
353 struct sta_info *sta)
354 {
355 struct hostapd_data *hapd = wpa_s->ifmsh->bss[0];
356 struct wpa_ssid *ssid = wpa_s->current_ssid;
357 struct rsn_pmksa_cache_entry *pmksa;
358 unsigned int rnd;
359 int ret;
360
361 if (!ssid) {
362 wpa_msg(wpa_s, MSG_DEBUG,
363 "AUTH: No current_ssid known to initiate new SAE");
364 return -1;
365 }
366
367 if (!sta->sae) {
368 sta->sae = os_zalloc(sizeof(*sta->sae));
369 if (sta->sae == NULL)
370 return -1;
371 }
372
373 pmksa = wpa_auth_pmksa_get(hapd->wpa_auth, sta->addr, NULL);
374 if (pmksa) {
375 if (!sta->wpa_sm)
376 sta->wpa_sm = wpa_auth_sta_init(hapd->wpa_auth,
377 sta->addr, NULL);
378 if (!sta->wpa_sm) {
379 wpa_printf(MSG_ERROR,
380 "mesh: Failed to initialize RSN state machine");
381 return -1;
382 }
383
384 wpa_printf(MSG_DEBUG,
385 "AUTH: Mesh PMKSA cache entry found for " MACSTR
386 " - try to use PMKSA caching instead of new SAE authentication",
387 MAC2STR(sta->addr));
388 wpa_auth_pmksa_set_to_sm(pmksa, sta->wpa_sm, hapd->wpa_auth,
389 sta->sae->pmkid, sta->sae->pmk);
390 sae_accept_sta(hapd, sta);
391 sta->mesh_sae_pmksa_caching = 1;
392 return 0;
393 }
394 sta->mesh_sae_pmksa_caching = 0;
395
396 if (mesh_rsn_build_sae_commit(wpa_s, ssid, sta))
397 return -1;
398
399 wpa_msg(wpa_s, MSG_DEBUG,
400 "AUTH: started authentication with SAE peer: " MACSTR,
401 MAC2STR(sta->addr));
402
403 ret = auth_sae_init_committed(hapd, sta);
404 if (ret)
405 return ret;
406
407 eloop_cancel_timeout(mesh_auth_timer, wpa_s, sta);
408 rnd = rand() % MESH_AUTH_TIMEOUT;
409 eloop_register_timeout(MESH_AUTH_TIMEOUT + rnd, 0, mesh_auth_timer,
410 wpa_s, sta);
411 return 0;
412 }
413
414
mesh_rsn_get_pmkid(struct mesh_rsn * rsn,struct sta_info * sta,u8 * pmkid)415 void mesh_rsn_get_pmkid(struct mesh_rsn *rsn, struct sta_info *sta, u8 *pmkid)
416 {
417 os_memcpy(pmkid, sta->sae->pmkid, SAE_PMKID_LEN);
418 }
419
420
421 static void
mesh_rsn_derive_aek(struct mesh_rsn * rsn,struct sta_info * sta)422 mesh_rsn_derive_aek(struct mesh_rsn *rsn, struct sta_info *sta)
423 {
424 u8 *myaddr = rsn->wpa_s->own_addr;
425 u8 *peer = sta->addr;
426 u8 *addr1, *addr2;
427 u8 context[RSN_SELECTOR_LEN + 2 * ETH_ALEN], *ptr = context;
428
429 /*
430 * AEK = KDF-Hash-256(PMK, "AEK Derivation", Selected AKM Suite ||
431 * min(localMAC, peerMAC) || max(localMAC, peerMAC))
432 */
433 /* Selected AKM Suite: SAE */
434 RSN_SELECTOR_PUT(ptr, RSN_AUTH_KEY_MGMT_SAE);
435 ptr += RSN_SELECTOR_LEN;
436
437 if (os_memcmp(myaddr, peer, ETH_ALEN) < 0) {
438 addr1 = myaddr;
439 addr2 = peer;
440 } else {
441 addr1 = peer;
442 addr2 = myaddr;
443 }
444 os_memcpy(ptr, addr1, ETH_ALEN);
445 ptr += ETH_ALEN;
446 os_memcpy(ptr, addr2, ETH_ALEN);
447
448 sha256_prf(sta->sae->pmk, sizeof(sta->sae->pmk), "AEK Derivation",
449 context, sizeof(context), sta->aek, sizeof(sta->aek));
450 }
451
452
453 /* derive mesh temporal key from pmk */
mesh_rsn_derive_mtk(struct wpa_supplicant * wpa_s,struct sta_info * sta)454 int mesh_rsn_derive_mtk(struct wpa_supplicant *wpa_s, struct sta_info *sta)
455 {
456 u8 *ptr;
457 u8 *min, *max;
458 u8 *myaddr = wpa_s->own_addr;
459 u8 *peer = sta->addr;
460 u8 context[2 * WPA_NONCE_LEN + 2 * 2 + RSN_SELECTOR_LEN + 2 * ETH_ALEN];
461
462 /*
463 * MTK = KDF-Hash-Length(PMK, "Temporal Key Derivation", min(localNonce,
464 * peerNonce) || max(localNonce, peerNonce) || min(localLinkID,
465 * peerLinkID) || max(localLinkID, peerLinkID) || Selected AKM Suite ||
466 * min(localMAC, peerMAC) || max(localMAC, peerMAC))
467 */
468 ptr = context;
469 if (os_memcmp(sta->my_nonce, sta->peer_nonce, WPA_NONCE_LEN) < 0) {
470 min = sta->my_nonce;
471 max = sta->peer_nonce;
472 } else {
473 min = sta->peer_nonce;
474 max = sta->my_nonce;
475 }
476 os_memcpy(ptr, min, WPA_NONCE_LEN);
477 ptr += WPA_NONCE_LEN;
478 os_memcpy(ptr, max, WPA_NONCE_LEN);
479 ptr += WPA_NONCE_LEN;
480
481 if (sta->my_lid < sta->peer_lid) {
482 WPA_PUT_LE16(ptr, sta->my_lid);
483 ptr += 2;
484 WPA_PUT_LE16(ptr, sta->peer_lid);
485 ptr += 2;
486 } else {
487 WPA_PUT_LE16(ptr, sta->peer_lid);
488 ptr += 2;
489 WPA_PUT_LE16(ptr, sta->my_lid);
490 ptr += 2;
491 }
492
493 /* Selected AKM Suite: SAE */
494 RSN_SELECTOR_PUT(ptr, RSN_AUTH_KEY_MGMT_SAE);
495 ptr += RSN_SELECTOR_LEN;
496
497 if (os_memcmp(myaddr, peer, ETH_ALEN) < 0) {
498 min = myaddr;
499 max = peer;
500 } else {
501 min = peer;
502 max = myaddr;
503 }
504 os_memcpy(ptr, min, ETH_ALEN);
505 ptr += ETH_ALEN;
506 os_memcpy(ptr, max, ETH_ALEN);
507
508 sta->mtk_len = wpa_cipher_key_len(wpa_s->mesh_rsn->pairwise_cipher);
509 sha256_prf(sta->sae->pmk, SAE_PMK_LEN,
510 "Temporal Key Derivation", context, sizeof(context),
511 sta->mtk, sta->mtk_len);
512 return 0;
513 }
514
515
mesh_rsn_init_ampe_sta(struct wpa_supplicant * wpa_s,struct sta_info * sta)516 void mesh_rsn_init_ampe_sta(struct wpa_supplicant *wpa_s, struct sta_info *sta)
517 {
518 if (random_get_bytes(sta->my_nonce, WPA_NONCE_LEN) < 0) {
519 wpa_printf(MSG_INFO, "mesh: Failed to derive random nonce");
520 /* TODO: How to handle this more cleanly? */
521 }
522 os_memset(sta->peer_nonce, 0, WPA_NONCE_LEN);
523 mesh_rsn_derive_aek(wpa_s->mesh_rsn, sta);
524 }
525
526
527 /* insert AMPE and encrypted MIC at @ie.
528 * @mesh_rsn: mesh RSN context
529 * @sta: STA we're sending to
530 * @cat: pointer to category code in frame header.
531 * @buf: wpabuf to add encrypted AMPE and MIC to.
532 * */
mesh_rsn_protect_frame(struct mesh_rsn * rsn,struct sta_info * sta,const u8 * cat,struct wpabuf * buf)533 int mesh_rsn_protect_frame(struct mesh_rsn *rsn, struct sta_info *sta,
534 const u8 *cat, struct wpabuf *buf)
535 {
536 struct ieee80211_ampe_ie *ampe;
537 u8 const *ie = wpabuf_head_u8(buf) + wpabuf_len(buf);
538 u8 *ampe_ie, *pos, *mic_payload;
539 const u8 *aad[] = { rsn->wpa_s->own_addr, sta->addr, cat };
540 const size_t aad_len[] = { ETH_ALEN, ETH_ALEN, ie - cat };
541 int ret = 0;
542 size_t len;
543
544 len = sizeof(*ampe);
545 if (cat[1] == PLINK_OPEN)
546 len += rsn->mgtk_len + WPA_KEY_RSC_LEN + 4;
547 if (cat[1] == PLINK_OPEN && rsn->igtk_len)
548 len += 2 + 6 + rsn->igtk_len;
549
550 if (2 + AES_BLOCK_SIZE + 2 + len > wpabuf_tailroom(buf)) {
551 wpa_printf(MSG_ERROR, "protect frame: buffer too small");
552 return -EINVAL;
553 }
554
555 ampe_ie = os_zalloc(2 + len);
556 if (!ampe_ie) {
557 wpa_printf(MSG_ERROR, "protect frame: out of memory");
558 return -ENOMEM;
559 }
560
561 /* IE: AMPE */
562 ampe_ie[0] = WLAN_EID_AMPE;
563 ampe_ie[1] = len;
564 ampe = (struct ieee80211_ampe_ie *) (ampe_ie + 2);
565
566 RSN_SELECTOR_PUT(ampe->selected_pairwise_suite,
567 RSN_CIPHER_SUITE_CCMP);
568 os_memcpy(ampe->local_nonce, sta->my_nonce, WPA_NONCE_LEN);
569 os_memcpy(ampe->peer_nonce, sta->peer_nonce, WPA_NONCE_LEN);
570
571 pos = (u8 *) (ampe + 1);
572 if (cat[1] != PLINK_OPEN)
573 goto skip_keys;
574
575 /* TODO: Key Replay Counter[8] optionally for
576 * Mesh Group Key Inform/Acknowledge frames */
577
578 /* TODO: static mgtk for now since we don't support rekeying! */
579 /*
580 * GTKdata[variable]:
581 * MGTK[variable] || Key RSC[8] || GTKExpirationTime[4]
582 */
583 os_memcpy(pos, rsn->mgtk, rsn->mgtk_len);
584 pos += rsn->mgtk_len;
585 wpa_drv_get_seqnum(rsn->wpa_s, NULL, rsn->mgtk_key_id, pos);
586 pos += WPA_KEY_RSC_LEN;
587 /* Use fixed GTKExpirationTime for now */
588 WPA_PUT_LE32(pos, 0xffffffff);
589 pos += 4;
590
591 /*
592 * IGTKdata[variable]:
593 * Key ID[2], IPN[6], IGTK[variable]
594 */
595 if (rsn->igtk_len) {
596 WPA_PUT_LE16(pos, rsn->igtk_key_id);
597 pos += 2;
598 wpa_drv_get_seqnum(rsn->wpa_s, NULL, rsn->igtk_key_id, pos);
599 pos += 6;
600 os_memcpy(pos, rsn->igtk, rsn->igtk_len);
601 }
602
603 skip_keys:
604 wpa_hexdump_key(MSG_DEBUG, "mesh: Plaintext AMPE element",
605 ampe_ie, 2 + len);
606
607 /* IE: MIC */
608 wpabuf_put_u8(buf, WLAN_EID_MIC);
609 wpabuf_put_u8(buf, AES_BLOCK_SIZE);
610 /* MIC field is output ciphertext */
611
612 /* encrypt after MIC */
613 mic_payload = wpabuf_put(buf, 2 + len + AES_BLOCK_SIZE);
614
615 if (aes_siv_encrypt(sta->aek, sizeof(sta->aek), ampe_ie, 2 + len, 3,
616 aad, aad_len, mic_payload)) {
617 wpa_printf(MSG_ERROR, "protect frame: failed to encrypt");
618 ret = -ENOMEM;
619 }
620
621 os_free(ampe_ie);
622
623 return ret;
624 }
625
626
mesh_rsn_process_ampe(struct wpa_supplicant * wpa_s,struct sta_info * sta,struct ieee802_11_elems * elems,const u8 * cat,const u8 * chosen_pmk,const u8 * start,size_t elems_len)627 int mesh_rsn_process_ampe(struct wpa_supplicant *wpa_s, struct sta_info *sta,
628 struct ieee802_11_elems *elems, const u8 *cat,
629 const u8 *chosen_pmk,
630 const u8 *start, size_t elems_len)
631 {
632 int ret = 0;
633 struct ieee80211_ampe_ie *ampe;
634 u8 null_nonce[WPA_NONCE_LEN] = {};
635 u8 ampe_eid;
636 u8 ampe_ie_len;
637 u8 *ampe_buf, *crypt = NULL, *pos, *end;
638 size_t crypt_len;
639 const u8 *aad[] = { sta->addr, wpa_s->own_addr, cat };
640 const size_t aad_len[] = { ETH_ALEN, ETH_ALEN,
641 elems->mic ? (elems->mic - 2) - cat : 0 };
642 size_t key_len;
643
644 if (!sta->sae) {
645 struct hostapd_data *hapd = wpa_s->ifmsh->bss[0];
646
647 if (!wpa_auth_pmksa_get(hapd->wpa_auth, sta->addr, NULL)) {
648 wpa_printf(MSG_INFO,
649 "Mesh RSN: SAE is not prepared yet");
650 return -1;
651 }
652 mesh_rsn_auth_sae_sta(wpa_s, sta);
653 }
654
655 if (chosen_pmk &&
656 (!sta->sae ||
657 os_memcmp(chosen_pmk, sta->sae->pmkid, PMKID_LEN) != 0)) {
658 wpa_msg(wpa_s, MSG_DEBUG,
659 "Mesh RSN: Invalid PMKID (Chosen PMK did not match calculated PMKID)");
660 return -1;
661 }
662
663 if (!elems->mic || elems->mic_len < AES_BLOCK_SIZE) {
664 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: missing mic ie");
665 return -1;
666 }
667
668 ampe_buf = (u8 *) elems->mic + elems->mic_len;
669 if ((int) elems_len < ampe_buf - start)
670 return -1;
671
672 crypt_len = elems_len - (elems->mic - start);
673 if (crypt_len < 2 + AES_BLOCK_SIZE) {
674 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: missing ampe ie");
675 return -1;
676 }
677
678 /* crypt is modified by siv_decrypt */
679 crypt = os_zalloc(crypt_len);
680 if (!crypt) {
681 wpa_printf(MSG_ERROR, "Mesh RSN: out of memory");
682 ret = -ENOMEM;
683 goto free;
684 }
685
686 os_memcpy(crypt, elems->mic, crypt_len);
687
688 if (aes_siv_decrypt(sta->aek, sizeof(sta->aek), crypt, crypt_len, 3,
689 aad, aad_len, ampe_buf)) {
690 wpa_printf(MSG_ERROR, "Mesh RSN: frame verification failed!");
691 ret = -2;
692 goto free;
693 }
694
695 crypt_len -= AES_BLOCK_SIZE;
696 wpa_hexdump_key(MSG_DEBUG, "mesh: Decrypted AMPE element",
697 ampe_buf, crypt_len);
698
699 ampe_eid = *ampe_buf++;
700 ampe_ie_len = *ampe_buf++;
701
702 if (ampe_eid != WLAN_EID_AMPE ||
703 (size_t) 2 + ampe_ie_len > crypt_len ||
704 ampe_ie_len < sizeof(struct ieee80211_ampe_ie)) {
705 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: invalid ampe ie");
706 ret = -1;
707 goto free;
708 }
709
710 ampe = (struct ieee80211_ampe_ie *) ampe_buf;
711 pos = (u8 *) (ampe + 1);
712 end = ampe_buf + ampe_ie_len;
713 if (os_memcmp(ampe->peer_nonce, null_nonce, WPA_NONCE_LEN) != 0 &&
714 os_memcmp(ampe->peer_nonce, sta->my_nonce, WPA_NONCE_LEN) != 0) {
715 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: invalid peer nonce");
716 ret = -1;
717 goto free;
718 }
719 os_memcpy(sta->peer_nonce, ampe->local_nonce,
720 sizeof(ampe->local_nonce));
721
722 /* TODO: Key Replay Counter[8] in Mesh Group Key Inform/Acknowledge
723 * frames */
724
725 /*
726 * GTKdata shall not be included in Mesh Peering Confirm. While the
727 * standard does not state the same about IGTKdata, that same constraint
728 * needs to apply for it. It makes no sense to include the keys in Mesh
729 * Peering Close frames either, so while the standard does not seem to
730 * have a shall statement for these, they are described without
731 * mentioning GTKdata.
732 *
733 * An earlier implementation used to add GTKdata to both Mesh Peering
734 * Open and Mesh Peering Confirm frames, so ignore the possibly present
735 * GTKdata frame without rejecting the frame as a backwards
736 * compatibility mechanism.
737 */
738 if (cat[1] != PLINK_OPEN) {
739 if (end > pos) {
740 wpa_hexdump_key(MSG_DEBUG,
741 "mesh: Ignore unexpected GTKdata(etc.) fields in the end of AMPE element in Mesh Peering Confirm/Close",
742 pos, end - pos);
743 }
744 goto free;
745 }
746
747 /*
748 * GTKdata[variable]:
749 * MGTK[variable] || Key RSC[8] || GTKExpirationTime[4]
750 */
751 sta->mgtk_key_id = 1; /* FIX: Where to get Key ID? */
752 key_len = wpa_cipher_key_len(wpa_s->mesh_rsn->group_cipher);
753 if ((int) key_len + WPA_KEY_RSC_LEN + 4 > end - pos) {
754 wpa_dbg(wpa_s, MSG_DEBUG, "mesh: Truncated AMPE element");
755 ret = -1;
756 goto free;
757 }
758 sta->mgtk_len = key_len;
759 os_memcpy(sta->mgtk, pos, sta->mgtk_len);
760 wpa_hexdump_key(MSG_DEBUG, "mesh: GTKdata - MGTK",
761 sta->mgtk, sta->mgtk_len);
762 pos += sta->mgtk_len;
763 wpa_hexdump(MSG_DEBUG, "mesh: GTKdata - MGTK - Key RSC",
764 pos, WPA_KEY_RSC_LEN);
765 os_memcpy(sta->mgtk_rsc, pos, sizeof(sta->mgtk_rsc));
766 pos += WPA_KEY_RSC_LEN;
767 wpa_printf(MSG_DEBUG,
768 "mesh: GTKdata - MGTK - GTKExpirationTime: %u seconds",
769 WPA_GET_LE32(pos));
770 pos += 4;
771
772 /*
773 * IGTKdata[variable]:
774 * Key ID[2], IPN[6], IGTK[variable]
775 */
776 key_len = wpa_cipher_key_len(wpa_s->mesh_rsn->mgmt_group_cipher);
777 if (end - pos >= (int) (2 + 6 + key_len)) {
778 sta->igtk_key_id = WPA_GET_LE16(pos);
779 wpa_printf(MSG_DEBUG, "mesh: IGTKdata - Key ID %u",
780 sta->igtk_key_id);
781 pos += 2;
782 os_memcpy(sta->igtk_rsc, pos, sizeof(sta->igtk_rsc));
783 wpa_hexdump(MSG_DEBUG, "mesh: IGTKdata - IPN",
784 sta->igtk_rsc, sizeof(sta->igtk_rsc));
785 pos += 6;
786 os_memcpy(sta->igtk, pos, key_len);
787 sta->igtk_len = key_len;
788 wpa_hexdump_key(MSG_DEBUG, "mesh: IGTKdata - IGTK",
789 sta->igtk, sta->igtk_len);
790 }
791
792 free:
793 os_free(crypt);
794 return ret;
795 }
796
