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 ssid->sae_password_id,
348 sta->sae);
349 }
350
351
352 /* initiate new SAE authentication with sta */
mesh_rsn_auth_sae_sta(struct wpa_supplicant * wpa_s,struct sta_info * sta)353 int mesh_rsn_auth_sae_sta(struct wpa_supplicant *wpa_s,
354 struct sta_info *sta)
355 {
356 struct hostapd_data *hapd = wpa_s->ifmsh->bss[0];
357 struct wpa_ssid *ssid = wpa_s->current_ssid;
358 struct rsn_pmksa_cache_entry *pmksa;
359 unsigned int rnd;
360 int ret;
361
362 if (!ssid) {
363 wpa_msg(wpa_s, MSG_DEBUG,
364 "AUTH: No current_ssid known to initiate new SAE");
365 return -1;
366 }
367
368 if (!sta->sae) {
369 sta->sae = os_zalloc(sizeof(*sta->sae));
370 if (sta->sae == NULL)
371 return -1;
372 }
373
374 pmksa = wpa_auth_pmksa_get(hapd->wpa_auth, sta->addr, NULL);
375 if (pmksa) {
376 if (!sta->wpa_sm)
377 sta->wpa_sm = wpa_auth_sta_init(hapd->wpa_auth,
378 sta->addr, NULL);
379 if (!sta->wpa_sm) {
380 wpa_printf(MSG_ERROR,
381 "mesh: Failed to initialize RSN state machine");
382 return -1;
383 }
384
385 wpa_printf(MSG_DEBUG,
386 "AUTH: Mesh PMKSA cache entry found for " MACSTR
387 " - try to use PMKSA caching instead of new SAE authentication",
388 MAC2STR(sta->addr));
389 wpa_auth_pmksa_set_to_sm(pmksa, sta->wpa_sm, hapd->wpa_auth,
390 sta->sae->pmkid, sta->sae->pmk);
391 sae_accept_sta(hapd, sta);
392 sta->mesh_sae_pmksa_caching = 1;
393 return 0;
394 }
395 sta->mesh_sae_pmksa_caching = 0;
396
397 if (mesh_rsn_build_sae_commit(wpa_s, ssid, sta))
398 return -1;
399
400 wpa_msg(wpa_s, MSG_DEBUG,
401 "AUTH: started authentication with SAE peer: " MACSTR,
402 MAC2STR(sta->addr));
403
404 ret = auth_sae_init_committed(hapd, sta);
405 if (ret)
406 return ret;
407
408 eloop_cancel_timeout(mesh_auth_timer, wpa_s, sta);
409 rnd = rand() % MESH_AUTH_TIMEOUT;
410 eloop_register_timeout(MESH_AUTH_TIMEOUT + rnd, 0, mesh_auth_timer,
411 wpa_s, sta);
412 return 0;
413 }
414
415
mesh_rsn_get_pmkid(struct mesh_rsn * rsn,struct sta_info * sta,u8 * pmkid)416 void mesh_rsn_get_pmkid(struct mesh_rsn *rsn, struct sta_info *sta, u8 *pmkid)
417 {
418 os_memcpy(pmkid, sta->sae->pmkid, SAE_PMKID_LEN);
419 }
420
421
422 static void
mesh_rsn_derive_aek(struct mesh_rsn * rsn,struct sta_info * sta)423 mesh_rsn_derive_aek(struct mesh_rsn *rsn, struct sta_info *sta)
424 {
425 u8 *myaddr = rsn->wpa_s->own_addr;
426 u8 *peer = sta->addr;
427 u8 *addr1, *addr2;
428 u8 context[RSN_SELECTOR_LEN + 2 * ETH_ALEN], *ptr = context;
429
430 /*
431 * AEK = KDF-Hash-256(PMK, "AEK Derivation", Selected AKM Suite ||
432 * min(localMAC, peerMAC) || max(localMAC, peerMAC))
433 */
434 /* Selected AKM Suite: SAE */
435 RSN_SELECTOR_PUT(ptr, RSN_AUTH_KEY_MGMT_SAE);
436 ptr += RSN_SELECTOR_LEN;
437
438 if (os_memcmp(myaddr, peer, ETH_ALEN) < 0) {
439 addr1 = myaddr;
440 addr2 = peer;
441 } else {
442 addr1 = peer;
443 addr2 = myaddr;
444 }
445 os_memcpy(ptr, addr1, ETH_ALEN);
446 ptr += ETH_ALEN;
447 os_memcpy(ptr, addr2, ETH_ALEN);
448
449 sha256_prf(sta->sae->pmk, sizeof(sta->sae->pmk), "AEK Derivation",
450 context, sizeof(context), sta->aek, sizeof(sta->aek));
451 }
452
453
454 /* derive mesh temporal key from pmk */
mesh_rsn_derive_mtk(struct wpa_supplicant * wpa_s,struct sta_info * sta)455 int mesh_rsn_derive_mtk(struct wpa_supplicant *wpa_s, struct sta_info *sta)
456 {
457 u8 *ptr;
458 u8 *min, *max;
459 u8 *myaddr = wpa_s->own_addr;
460 u8 *peer = sta->addr;
461 u8 context[2 * WPA_NONCE_LEN + 2 * 2 + RSN_SELECTOR_LEN + 2 * ETH_ALEN];
462
463 /*
464 * MTK = KDF-Hash-Length(PMK, "Temporal Key Derivation", min(localNonce,
465 * peerNonce) || max(localNonce, peerNonce) || min(localLinkID,
466 * peerLinkID) || max(localLinkID, peerLinkID) || Selected AKM Suite ||
467 * min(localMAC, peerMAC) || max(localMAC, peerMAC))
468 */
469 ptr = context;
470 if (os_memcmp(sta->my_nonce, sta->peer_nonce, WPA_NONCE_LEN) < 0) {
471 min = sta->my_nonce;
472 max = sta->peer_nonce;
473 } else {
474 min = sta->peer_nonce;
475 max = sta->my_nonce;
476 }
477 os_memcpy(ptr, min, WPA_NONCE_LEN);
478 ptr += WPA_NONCE_LEN;
479 os_memcpy(ptr, max, WPA_NONCE_LEN);
480 ptr += WPA_NONCE_LEN;
481
482 if (sta->my_lid < sta->peer_lid) {
483 WPA_PUT_LE16(ptr, sta->my_lid);
484 ptr += 2;
485 WPA_PUT_LE16(ptr, sta->peer_lid);
486 ptr += 2;
487 } else {
488 WPA_PUT_LE16(ptr, sta->peer_lid);
489 ptr += 2;
490 WPA_PUT_LE16(ptr, sta->my_lid);
491 ptr += 2;
492 }
493
494 /* Selected AKM Suite: SAE */
495 RSN_SELECTOR_PUT(ptr, RSN_AUTH_KEY_MGMT_SAE);
496 ptr += RSN_SELECTOR_LEN;
497
498 if (os_memcmp(myaddr, peer, ETH_ALEN) < 0) {
499 min = myaddr;
500 max = peer;
501 } else {
502 min = peer;
503 max = myaddr;
504 }
505 os_memcpy(ptr, min, ETH_ALEN);
506 ptr += ETH_ALEN;
507 os_memcpy(ptr, max, ETH_ALEN);
508
509 sta->mtk_len = wpa_cipher_key_len(wpa_s->mesh_rsn->pairwise_cipher);
510 sha256_prf(sta->sae->pmk, SAE_PMK_LEN,
511 "Temporal Key Derivation", context, sizeof(context),
512 sta->mtk, sta->mtk_len);
513 return 0;
514 }
515
516
mesh_rsn_init_ampe_sta(struct wpa_supplicant * wpa_s,struct sta_info * sta)517 void mesh_rsn_init_ampe_sta(struct wpa_supplicant *wpa_s, struct sta_info *sta)
518 {
519 if (random_get_bytes(sta->my_nonce, WPA_NONCE_LEN) < 0) {
520 wpa_printf(MSG_INFO, "mesh: Failed to derive random nonce");
521 /* TODO: How to handle this more cleanly? */
522 }
523 os_memset(sta->peer_nonce, 0, WPA_NONCE_LEN);
524 mesh_rsn_derive_aek(wpa_s->mesh_rsn, sta);
525 }
526
527
528 /* insert AMPE and encrypted MIC at @ie.
529 * @mesh_rsn: mesh RSN context
530 * @sta: STA we're sending to
531 * @cat: pointer to category code in frame header.
532 * @buf: wpabuf to add encrypted AMPE and MIC to.
533 * */
mesh_rsn_protect_frame(struct mesh_rsn * rsn,struct sta_info * sta,const u8 * cat,struct wpabuf * buf)534 int mesh_rsn_protect_frame(struct mesh_rsn *rsn, struct sta_info *sta,
535 const u8 *cat, struct wpabuf *buf)
536 {
537 struct ieee80211_ampe_ie *ampe;
538 u8 const *ie = wpabuf_head_u8(buf) + wpabuf_len(buf);
539 u8 *ampe_ie, *pos, *mic_payload;
540 const u8 *aad[] = { rsn->wpa_s->own_addr, sta->addr, cat };
541 const size_t aad_len[] = { ETH_ALEN, ETH_ALEN, ie - cat };
542 int ret = 0;
543 size_t len;
544
545 len = sizeof(*ampe);
546 if (cat[1] == PLINK_OPEN)
547 len += rsn->mgtk_len + WPA_KEY_RSC_LEN + 4;
548 if (cat[1] == PLINK_OPEN && rsn->igtk_len)
549 len += 2 + 6 + rsn->igtk_len;
550
551 if (2 + AES_BLOCK_SIZE + 2 + len > wpabuf_tailroom(buf)) {
552 wpa_printf(MSG_ERROR, "protect frame: buffer too small");
553 return -EINVAL;
554 }
555
556 ampe_ie = os_zalloc(2 + len);
557 if (!ampe_ie) {
558 wpa_printf(MSG_ERROR, "protect frame: out of memory");
559 return -ENOMEM;
560 }
561
562 /* IE: AMPE */
563 ampe_ie[0] = WLAN_EID_AMPE;
564 ampe_ie[1] = len;
565 ampe = (struct ieee80211_ampe_ie *) (ampe_ie + 2);
566
567 RSN_SELECTOR_PUT(ampe->selected_pairwise_suite,
568 RSN_CIPHER_SUITE_CCMP);
569 os_memcpy(ampe->local_nonce, sta->my_nonce, WPA_NONCE_LEN);
570 os_memcpy(ampe->peer_nonce, sta->peer_nonce, WPA_NONCE_LEN);
571
572 pos = (u8 *) (ampe + 1);
573 if (cat[1] != PLINK_OPEN)
574 goto skip_keys;
575
576 /* TODO: Key Replay Counter[8] optionally for
577 * Mesh Group Key Inform/Acknowledge frames */
578
579 /* TODO: static mgtk for now since we don't support rekeying! */
580 /*
581 * GTKdata[variable]:
582 * MGTK[variable] || Key RSC[8] || GTKExpirationTime[4]
583 */
584 os_memcpy(pos, rsn->mgtk, rsn->mgtk_len);
585 pos += rsn->mgtk_len;
586 wpa_drv_get_seqnum(rsn->wpa_s, NULL, rsn->mgtk_key_id, pos);
587 pos += WPA_KEY_RSC_LEN;
588 /* Use fixed GTKExpirationTime for now */
589 WPA_PUT_LE32(pos, 0xffffffff);
590 pos += 4;
591
592 /*
593 * IGTKdata[variable]:
594 * Key ID[2], IPN[6], IGTK[variable]
595 */
596 if (rsn->igtk_len) {
597 WPA_PUT_LE16(pos, rsn->igtk_key_id);
598 pos += 2;
599 wpa_drv_get_seqnum(rsn->wpa_s, NULL, rsn->igtk_key_id, pos);
600 pos += 6;
601 os_memcpy(pos, rsn->igtk, rsn->igtk_len);
602 }
603
604 skip_keys:
605 wpa_hexdump_key(MSG_DEBUG, "mesh: Plaintext AMPE element",
606 ampe_ie, 2 + len);
607
608 /* IE: MIC */
609 wpabuf_put_u8(buf, WLAN_EID_MIC);
610 wpabuf_put_u8(buf, AES_BLOCK_SIZE);
611 /* MIC field is output ciphertext */
612
613 /* encrypt after MIC */
614 mic_payload = wpabuf_put(buf, 2 + len + AES_BLOCK_SIZE);
615
616 if (aes_siv_encrypt(sta->aek, sizeof(sta->aek), ampe_ie, 2 + len, 3,
617 aad, aad_len, mic_payload)) {
618 wpa_printf(MSG_ERROR, "protect frame: failed to encrypt");
619 ret = -ENOMEM;
620 }
621
622 os_free(ampe_ie);
623
624 return ret;
625 }
626
627
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)628 int mesh_rsn_process_ampe(struct wpa_supplicant *wpa_s, struct sta_info *sta,
629 struct ieee802_11_elems *elems, const u8 *cat,
630 const u8 *chosen_pmk,
631 const u8 *start, size_t elems_len)
632 {
633 int ret = 0;
634 struct ieee80211_ampe_ie *ampe;
635 u8 null_nonce[WPA_NONCE_LEN] = {};
636 u8 ampe_eid;
637 u8 ampe_ie_len;
638 u8 *ampe_buf, *crypt = NULL, *pos, *end;
639 size_t crypt_len;
640 const u8 *aad[] = { sta->addr, wpa_s->own_addr, cat };
641 const size_t aad_len[] = { ETH_ALEN, ETH_ALEN,
642 elems->mic ? (elems->mic - 2) - cat : 0 };
643 size_t key_len;
644
645 if (!sta->sae) {
646 struct hostapd_data *hapd = wpa_s->ifmsh->bss[0];
647
648 if (!wpa_auth_pmksa_get(hapd->wpa_auth, sta->addr, NULL)) {
649 wpa_printf(MSG_INFO,
650 "Mesh RSN: SAE is not prepared yet");
651 return -1;
652 }
653 mesh_rsn_auth_sae_sta(wpa_s, sta);
654 }
655
656 if (chosen_pmk &&
657 (!sta->sae ||
658 os_memcmp(chosen_pmk, sta->sae->pmkid, PMKID_LEN) != 0)) {
659 wpa_msg(wpa_s, MSG_DEBUG,
660 "Mesh RSN: Invalid PMKID (Chosen PMK did not match calculated PMKID)");
661 return -1;
662 }
663
664 if (!elems->mic || elems->mic_len < AES_BLOCK_SIZE) {
665 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: missing mic ie");
666 return -1;
667 }
668
669 ampe_buf = (u8 *) elems->mic + elems->mic_len;
670 if ((int) elems_len < ampe_buf - start)
671 return -1;
672
673 crypt_len = elems_len - (elems->mic - start);
674 if (crypt_len < 2 + AES_BLOCK_SIZE) {
675 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: missing ampe ie");
676 return -1;
677 }
678
679 /* crypt is modified by siv_decrypt */
680 crypt = os_zalloc(crypt_len);
681 if (!crypt) {
682 wpa_printf(MSG_ERROR, "Mesh RSN: out of memory");
683 ret = -ENOMEM;
684 goto free;
685 }
686
687 os_memcpy(crypt, elems->mic, crypt_len);
688
689 if (aes_siv_decrypt(sta->aek, sizeof(sta->aek), crypt, crypt_len, 3,
690 aad, aad_len, ampe_buf)) {
691 wpa_printf(MSG_ERROR, "Mesh RSN: frame verification failed!");
692 ret = -2;
693 goto free;
694 }
695
696 crypt_len -= AES_BLOCK_SIZE;
697 wpa_hexdump_key(MSG_DEBUG, "mesh: Decrypted AMPE element",
698 ampe_buf, crypt_len);
699
700 ampe_eid = *ampe_buf++;
701 ampe_ie_len = *ampe_buf++;
702
703 if (ampe_eid != WLAN_EID_AMPE ||
704 (size_t) 2 + ampe_ie_len > crypt_len ||
705 ampe_ie_len < sizeof(struct ieee80211_ampe_ie)) {
706 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: invalid ampe ie");
707 ret = -1;
708 goto free;
709 }
710
711 ampe = (struct ieee80211_ampe_ie *) ampe_buf;
712 pos = (u8 *) (ampe + 1);
713 end = ampe_buf + ampe_ie_len;
714 if (os_memcmp(ampe->peer_nonce, null_nonce, WPA_NONCE_LEN) != 0 &&
715 os_memcmp(ampe->peer_nonce, sta->my_nonce, WPA_NONCE_LEN) != 0) {
716 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: invalid peer nonce");
717 ret = -1;
718 goto free;
719 }
720 os_memcpy(sta->peer_nonce, ampe->local_nonce,
721 sizeof(ampe->local_nonce));
722
723 /* TODO: Key Replay Counter[8] in Mesh Group Key Inform/Acknowledge
724 * frames */
725
726 /*
727 * GTKdata shall not be included in Mesh Peering Confirm. While the
728 * standard does not state the same about IGTKdata, that same constraint
729 * needs to apply for it. It makes no sense to include the keys in Mesh
730 * Peering Close frames either, so while the standard does not seem to
731 * have a shall statement for these, they are described without
732 * mentioning GTKdata.
733 *
734 * An earlier implementation used to add GTKdata to both Mesh Peering
735 * Open and Mesh Peering Confirm frames, so ignore the possibly present
736 * GTKdata frame without rejecting the frame as a backwards
737 * compatibility mechanism.
738 */
739 if (cat[1] != PLINK_OPEN) {
740 if (end > pos) {
741 wpa_hexdump_key(MSG_DEBUG,
742 "mesh: Ignore unexpected GTKdata(etc.) fields in the end of AMPE element in Mesh Peering Confirm/Close",
743 pos, end - pos);
744 }
745 goto free;
746 }
747
748 /*
749 * GTKdata[variable]:
750 * MGTK[variable] || Key RSC[8] || GTKExpirationTime[4]
751 */
752 sta->mgtk_key_id = 1; /* FIX: Where to get Key ID? */
753 key_len = wpa_cipher_key_len(wpa_s->mesh_rsn->group_cipher);
754 if ((int) key_len + WPA_KEY_RSC_LEN + 4 > end - pos) {
755 wpa_dbg(wpa_s, MSG_DEBUG, "mesh: Truncated AMPE element");
756 ret = -1;
757 goto free;
758 }
759 sta->mgtk_len = key_len;
760 os_memcpy(sta->mgtk, pos, sta->mgtk_len);
761 wpa_hexdump_key(MSG_DEBUG, "mesh: GTKdata - MGTK",
762 sta->mgtk, sta->mgtk_len);
763 pos += sta->mgtk_len;
764 wpa_hexdump(MSG_DEBUG, "mesh: GTKdata - MGTK - Key RSC",
765 pos, WPA_KEY_RSC_LEN);
766 os_memcpy(sta->mgtk_rsc, pos, sizeof(sta->mgtk_rsc));
767 pos += WPA_KEY_RSC_LEN;
768 wpa_printf(MSG_DEBUG,
769 "mesh: GTKdata - MGTK - GTKExpirationTime: %u seconds",
770 WPA_GET_LE32(pos));
771 pos += 4;
772
773 /*
774 * IGTKdata[variable]:
775 * Key ID[2], IPN[6], IGTK[variable]
776 */
777 key_len = wpa_cipher_key_len(wpa_s->mesh_rsn->mgmt_group_cipher);
778 if (end - pos >= (int) (2 + 6 + key_len)) {
779 sta->igtk_key_id = WPA_GET_LE16(pos);
780 wpa_printf(MSG_DEBUG, "mesh: IGTKdata - Key ID %u",
781 sta->igtk_key_id);
782 pos += 2;
783 os_memcpy(sta->igtk_rsc, pos, sizeof(sta->igtk_rsc));
784 wpa_hexdump(MSG_DEBUG, "mesh: IGTKdata - IPN",
785 sta->igtk_rsc, sizeof(sta->igtk_rsc));
786 pos += 6;
787 os_memcpy(sta->igtk, pos, key_len);
788 sta->igtk_len = key_len;
789 wpa_hexdump_key(MSG_DEBUG, "mesh: IGTKdata - IGTK",
790 sta->igtk, sta->igtk_len);
791 }
792
793 free:
794 os_free(crypt);
795 return ret;
796 }
797