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, -1, 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
auth_for_each_sta(void * ctx,int (* cb)(struct wpa_state_machine * sm,void * ctx),void * cb_ctx)145 static int auth_for_each_sta(
146 void *ctx, int (*cb)(struct wpa_state_machine *sm, void *ctx),
147 void *cb_ctx)
148 {
149 struct mesh_rsn *rsn = ctx;
150 struct hostapd_data *hapd;
151 struct sta_info *sta;
152
153 hapd = rsn->wpa_s->ifmsh->bss[0];
154 for (sta = hapd->sta_list; sta; sta = sta->next) {
155 if (sta->wpa_sm && cb(sta->wpa_sm, cb_ctx))
156 return 1;
157 }
158 return 0;
159 }
160
161
__mesh_rsn_auth_init(struct mesh_rsn * rsn,const u8 * addr,enum mfp_options ieee80211w,int ocv)162 static int __mesh_rsn_auth_init(struct mesh_rsn *rsn, const u8 *addr,
163 enum mfp_options ieee80211w, int ocv)
164 {
165 struct wpa_auth_config conf;
166 static const struct wpa_auth_callbacks cb = {
167 .logger = auth_logger,
168 .get_psk = auth_get_psk,
169 .set_key = auth_set_key,
170 .start_ampe = auth_start_ampe,
171 .for_each_sta = auth_for_each_sta,
172 };
173 u8 seq[6] = {};
174
175 wpa_printf(MSG_DEBUG, "AUTH: Initializing group state machine");
176
177 os_memset(&conf, 0, sizeof(conf));
178 conf.wpa = WPA_PROTO_RSN;
179 conf.wpa_key_mgmt = WPA_KEY_MGMT_SAE;
180 conf.wpa_pairwise = rsn->pairwise_cipher;
181 conf.rsn_pairwise = rsn->pairwise_cipher;
182 conf.wpa_group = rsn->group_cipher;
183 conf.eapol_version = 0;
184 conf.wpa_group_rekey = -1;
185 conf.wpa_group_update_count = 4;
186 conf.wpa_pairwise_update_count = 4;
187 conf.ieee80211w = ieee80211w;
188 if (ieee80211w != NO_MGMT_FRAME_PROTECTION)
189 conf.group_mgmt_cipher = rsn->mgmt_group_cipher;
190 #ifdef CONFIG_OCV
191 conf.ocv = ocv;
192 #endif /* CONFIG_OCV */
193
194 rsn->auth = wpa_init(addr, &conf, &cb, rsn);
195 if (rsn->auth == NULL) {
196 wpa_printf(MSG_DEBUG, "AUTH: wpa_init() failed");
197 return -1;
198 }
199
200 /* TODO: support rekeying */
201 rsn->mgtk_len = wpa_cipher_key_len(conf.wpa_group);
202 if (random_get_bytes(rsn->mgtk, rsn->mgtk_len) < 0)
203 return -1;
204 rsn->mgtk_key_id = 1;
205
206 if (ieee80211w != NO_MGMT_FRAME_PROTECTION) {
207 rsn->igtk_len = wpa_cipher_key_len(conf.group_mgmt_cipher);
208 if (random_get_bytes(rsn->igtk, rsn->igtk_len) < 0)
209 return -1;
210 rsn->igtk_key_id = 4;
211
212 /* group mgmt */
213 wpa_hexdump_key(MSG_DEBUG, "mesh: Own TX IGTK",
214 rsn->igtk, rsn->igtk_len);
215 wpa_drv_set_key(rsn->wpa_s, -1,
216 wpa_cipher_to_alg(rsn->mgmt_group_cipher),
217 broadcast_ether_addr,
218 rsn->igtk_key_id, 1,
219 seq, sizeof(seq), rsn->igtk, rsn->igtk_len,
220 KEY_FLAG_GROUP_TX_DEFAULT);
221 }
222
223 /* group privacy / data frames */
224 wpa_hexdump_key(MSG_DEBUG, "mesh: Own TX MGTK",
225 rsn->mgtk, rsn->mgtk_len);
226 wpa_drv_set_key(rsn->wpa_s, -1, wpa_cipher_to_alg(rsn->group_cipher),
227 broadcast_ether_addr,
228 rsn->mgtk_key_id, 1, seq, sizeof(seq),
229 rsn->mgtk, rsn->mgtk_len, KEY_FLAG_GROUP_TX_DEFAULT);
230
231 return 0;
232 }
233
234
mesh_rsn_deinit(struct mesh_rsn * rsn)235 static void mesh_rsn_deinit(struct mesh_rsn *rsn)
236 {
237 os_memset(rsn->mgtk, 0, sizeof(rsn->mgtk));
238 rsn->mgtk_len = 0;
239 os_memset(rsn->igtk, 0, sizeof(rsn->igtk));
240 rsn->igtk_len = 0;
241 if (rsn->auth)
242 wpa_deinit(rsn->auth);
243 }
244
245
mesh_rsn_auth_init(struct wpa_supplicant * wpa_s,struct mesh_conf * conf)246 struct mesh_rsn *mesh_rsn_auth_init(struct wpa_supplicant *wpa_s,
247 struct mesh_conf *conf)
248 {
249 struct mesh_rsn *mesh_rsn;
250 struct hostapd_data *bss = wpa_s->ifmsh->bss[0];
251 const u8 *ie;
252 size_t ie_len;
253 #ifdef CONFIG_PMKSA_CACHE_EXTERNAL
254 struct external_pmksa_cache *entry;
255 #endif /* CONFIG_PMKSA_CACHE_EXTERNAL */
256
257 mesh_rsn = os_zalloc(sizeof(*mesh_rsn));
258 if (mesh_rsn == NULL)
259 return NULL;
260 mesh_rsn->wpa_s = wpa_s;
261 mesh_rsn->pairwise_cipher = conf->pairwise_cipher;
262 mesh_rsn->group_cipher = conf->group_cipher;
263 mesh_rsn->mgmt_group_cipher = conf->mgmt_group_cipher;
264
265 if (__mesh_rsn_auth_init(mesh_rsn, wpa_s->own_addr,
266 conf->ieee80211w, conf->ocv) < 0) {
267 mesh_rsn_deinit(mesh_rsn);
268 os_free(mesh_rsn);
269 return NULL;
270 }
271
272 bss->wpa_auth = mesh_rsn->auth;
273
274 #ifdef CONFIG_PMKSA_CACHE_EXTERNAL
275 while ((entry = dl_list_last(&wpa_s->mesh_external_pmksa_cache,
276 struct external_pmksa_cache,
277 list)) != NULL) {
278 int ret;
279
280 ret = wpa_auth_pmksa_add_entry(bss->wpa_auth,
281 entry->pmksa_cache);
282 dl_list_del(&entry->list);
283 os_free(entry);
284
285 if (ret < 0)
286 return NULL;
287 }
288 #endif /* CONFIG_PMKSA_CACHE_EXTERNAL */
289
290 ie = wpa_auth_get_wpa_ie(mesh_rsn->auth, &ie_len);
291 conf->rsn_ie = (u8 *) ie;
292 conf->rsn_ie_len = ie_len;
293
294 wpa_supplicant_rsn_supp_set_config(wpa_s, wpa_s->current_ssid);
295
296 return mesh_rsn;
297 }
298
299
index_within_array(const int * array,int idx)300 static int index_within_array(const int *array, int idx)
301 {
302 int i;
303
304 for (i = 0; i < idx; i++) {
305 if (array[i] == -1)
306 return 0;
307 }
308
309 return 1;
310 }
311
312
mesh_rsn_sae_group(struct wpa_supplicant * wpa_s,struct sae_data * sae)313 static int mesh_rsn_sae_group(struct wpa_supplicant *wpa_s,
314 struct sae_data *sae)
315 {
316 int *groups = wpa_s->ifmsh->bss[0]->conf->sae_groups;
317
318 /* Configuration may have changed, so validate current index */
319 if (!index_within_array(groups, wpa_s->mesh_rsn->sae_group_index))
320 return -1;
321
322 for (;;) {
323 int group = groups[wpa_s->mesh_rsn->sae_group_index];
324
325 if (group <= 0)
326 break;
327 if (sae_set_group(sae, group) == 0) {
328 wpa_dbg(wpa_s, MSG_DEBUG, "SME: Selected SAE group %d",
329 sae->group);
330 return 0;
331 }
332 wpa_s->mesh_rsn->sae_group_index++;
333 }
334
335 return -1;
336 }
337
338
mesh_rsn_build_sae_commit(struct wpa_supplicant * wpa_s,struct wpa_ssid * ssid,struct sta_info * sta)339 static int mesh_rsn_build_sae_commit(struct wpa_supplicant *wpa_s,
340 struct wpa_ssid *ssid,
341 struct sta_info *sta)
342 {
343 const char *password;
344
345 password = ssid->sae_password;
346 if (!password)
347 password = ssid->passphrase;
348 if (!password) {
349 wpa_msg(wpa_s, MSG_DEBUG, "SAE: No password available");
350 return -1;
351 }
352
353 if (mesh_rsn_sae_group(wpa_s, sta->sae) < 0) {
354 wpa_msg(wpa_s, MSG_DEBUG, "SAE: Failed to select group");
355 return -1;
356 }
357
358 if (sta->sae->tmp && !sta->sae->tmp->pw_id && ssid->sae_password_id) {
359 sta->sae->tmp->pw_id = os_strdup(ssid->sae_password_id);
360 if (!sta->sae->tmp->pw_id)
361 return -1;
362 }
363 return sae_prepare_commit(wpa_s->own_addr, sta->addr,
364 (u8 *) password, os_strlen(password),
365 sta->sae);
366 }
367
368
369 /* initiate new SAE authentication with sta */
mesh_rsn_auth_sae_sta(struct wpa_supplicant * wpa_s,struct sta_info * sta)370 int mesh_rsn_auth_sae_sta(struct wpa_supplicant *wpa_s,
371 struct sta_info *sta)
372 {
373 struct hostapd_data *hapd = wpa_s->ifmsh->bss[0];
374 struct wpa_ssid *ssid = wpa_s->current_ssid;
375 struct rsn_pmksa_cache_entry *pmksa;
376 unsigned int rnd;
377 int ret;
378
379 if (!ssid) {
380 wpa_msg(wpa_s, MSG_DEBUG,
381 "AUTH: No current_ssid known to initiate new SAE");
382 return -1;
383 }
384
385 if (!sta->sae) {
386 sta->sae = os_zalloc(sizeof(*sta->sae));
387 if (sta->sae == NULL)
388 return -1;
389 }
390
391 pmksa = wpa_auth_pmksa_get(hapd->wpa_auth, sta->addr, NULL);
392 if (pmksa) {
393 if (!sta->wpa_sm)
394 sta->wpa_sm = wpa_auth_sta_init(hapd->wpa_auth,
395 sta->addr, NULL);
396 if (!sta->wpa_sm) {
397 wpa_printf(MSG_ERROR,
398 "mesh: Failed to initialize RSN state machine");
399 return -1;
400 }
401
402 wpa_printf(MSG_DEBUG,
403 "AUTH: Mesh PMKSA cache entry found for " MACSTR
404 " - try to use PMKSA caching instead of new SAE authentication",
405 MAC2STR(sta->addr));
406 wpa_auth_pmksa_set_to_sm(pmksa, sta->wpa_sm, hapd->wpa_auth,
407 sta->sae->pmkid, sta->sae->pmk,
408 &sta->sae->pmk_len);
409 sae_accept_sta(hapd, sta);
410 sta->mesh_sae_pmksa_caching = 1;
411 return 0;
412 }
413 sta->mesh_sae_pmksa_caching = 0;
414
415 if (mesh_rsn_build_sae_commit(wpa_s, ssid, sta))
416 return -1;
417
418 wpa_msg(wpa_s, MSG_DEBUG,
419 "AUTH: started authentication with SAE peer: " MACSTR,
420 MAC2STR(sta->addr));
421
422 ret = auth_sae_init_committed(hapd, sta);
423 if (ret)
424 return ret;
425
426 eloop_cancel_timeout(mesh_auth_timer, wpa_s, sta);
427 rnd = rand() % MESH_AUTH_TIMEOUT;
428 eloop_register_timeout(MESH_AUTH_TIMEOUT + rnd, 0, mesh_auth_timer,
429 wpa_s, sta);
430 return 0;
431 }
432
433
mesh_rsn_get_pmkid(struct mesh_rsn * rsn,struct sta_info * sta,u8 * pmkid)434 void mesh_rsn_get_pmkid(struct mesh_rsn *rsn, struct sta_info *sta, u8 *pmkid)
435 {
436 os_memcpy(pmkid, sta->sae->pmkid, SAE_PMKID_LEN);
437 }
438
439
440 static void
mesh_rsn_derive_aek(struct mesh_rsn * rsn,struct sta_info * sta)441 mesh_rsn_derive_aek(struct mesh_rsn *rsn, struct sta_info *sta)
442 {
443 u8 *myaddr = rsn->wpa_s->own_addr;
444 u8 *peer = sta->addr;
445 u8 *addr1, *addr2;
446 u8 context[RSN_SELECTOR_LEN + 2 * ETH_ALEN], *ptr = context;
447
448 /*
449 * AEK = KDF-Hash-256(PMK, "AEK Derivation", Selected AKM Suite ||
450 * min(localMAC, peerMAC) || max(localMAC, peerMAC))
451 */
452 /* Selected AKM Suite: SAE */
453 RSN_SELECTOR_PUT(ptr, RSN_AUTH_KEY_MGMT_SAE);
454 ptr += RSN_SELECTOR_LEN;
455
456 if (os_memcmp(myaddr, peer, ETH_ALEN) < 0) {
457 addr1 = myaddr;
458 addr2 = peer;
459 } else {
460 addr1 = peer;
461 addr2 = myaddr;
462 }
463 os_memcpy(ptr, addr1, ETH_ALEN);
464 ptr += ETH_ALEN;
465 os_memcpy(ptr, addr2, ETH_ALEN);
466
467 sha256_prf(sta->sae->pmk, sizeof(sta->sae->pmk), "AEK Derivation",
468 context, sizeof(context), sta->aek, sizeof(sta->aek));
469 }
470
471
472 /* derive mesh temporal key from pmk */
mesh_rsn_derive_mtk(struct wpa_supplicant * wpa_s,struct sta_info * sta)473 int mesh_rsn_derive_mtk(struct wpa_supplicant *wpa_s, struct sta_info *sta)
474 {
475 u8 *ptr;
476 u8 *min, *max;
477 u8 *myaddr = wpa_s->own_addr;
478 u8 *peer = sta->addr;
479 u8 context[2 * WPA_NONCE_LEN + 2 * 2 + RSN_SELECTOR_LEN + 2 * ETH_ALEN];
480
481 /*
482 * MTK = KDF-Hash-Length(PMK, "Temporal Key Derivation", min(localNonce,
483 * peerNonce) || max(localNonce, peerNonce) || min(localLinkID,
484 * peerLinkID) || max(localLinkID, peerLinkID) || Selected AKM Suite ||
485 * min(localMAC, peerMAC) || max(localMAC, peerMAC))
486 */
487 ptr = context;
488 if (os_memcmp(sta->my_nonce, sta->peer_nonce, WPA_NONCE_LEN) < 0) {
489 min = sta->my_nonce;
490 max = sta->peer_nonce;
491 } else {
492 min = sta->peer_nonce;
493 max = sta->my_nonce;
494 }
495 os_memcpy(ptr, min, WPA_NONCE_LEN);
496 ptr += WPA_NONCE_LEN;
497 os_memcpy(ptr, max, WPA_NONCE_LEN);
498 ptr += WPA_NONCE_LEN;
499
500 if (sta->my_lid < sta->peer_lid) {
501 WPA_PUT_LE16(ptr, sta->my_lid);
502 ptr += 2;
503 WPA_PUT_LE16(ptr, sta->peer_lid);
504 ptr += 2;
505 } else {
506 WPA_PUT_LE16(ptr, sta->peer_lid);
507 ptr += 2;
508 WPA_PUT_LE16(ptr, sta->my_lid);
509 ptr += 2;
510 }
511
512 /* Selected AKM Suite: SAE */
513 RSN_SELECTOR_PUT(ptr, RSN_AUTH_KEY_MGMT_SAE);
514 ptr += RSN_SELECTOR_LEN;
515
516 if (os_memcmp(myaddr, peer, ETH_ALEN) < 0) {
517 min = myaddr;
518 max = peer;
519 } else {
520 min = peer;
521 max = myaddr;
522 }
523 os_memcpy(ptr, min, ETH_ALEN);
524 ptr += ETH_ALEN;
525 os_memcpy(ptr, max, ETH_ALEN);
526
527 sta->mtk_len = wpa_cipher_key_len(wpa_s->mesh_rsn->pairwise_cipher);
528 sha256_prf(sta->sae->pmk, SAE_PMK_LEN,
529 "Temporal Key Derivation", context, sizeof(context),
530 sta->mtk, sta->mtk_len);
531 return 0;
532 }
533
534
mesh_rsn_init_ampe_sta(struct wpa_supplicant * wpa_s,struct sta_info * sta)535 void mesh_rsn_init_ampe_sta(struct wpa_supplicant *wpa_s, struct sta_info *sta)
536 {
537 if (random_get_bytes(sta->my_nonce, WPA_NONCE_LEN) < 0) {
538 wpa_printf(MSG_INFO, "mesh: Failed to derive random nonce");
539 /* TODO: How to handle this more cleanly? */
540 }
541 os_memset(sta->peer_nonce, 0, WPA_NONCE_LEN);
542 mesh_rsn_derive_aek(wpa_s->mesh_rsn, sta);
543 }
544
545
546 /* insert AMPE and encrypted MIC at @ie.
547 * @mesh_rsn: mesh RSN context
548 * @sta: STA we're sending to
549 * @cat: pointer to category code in frame header.
550 * @buf: wpabuf to add encrypted AMPE and MIC to.
551 * */
mesh_rsn_protect_frame(struct mesh_rsn * rsn,struct sta_info * sta,const u8 * cat,struct wpabuf * buf)552 int mesh_rsn_protect_frame(struct mesh_rsn *rsn, struct sta_info *sta,
553 const u8 *cat, struct wpabuf *buf)
554 {
555 struct ieee80211_ampe_ie *ampe;
556 u8 const *ie = wpabuf_head_u8(buf) + wpabuf_len(buf);
557 u8 *ampe_ie, *pos, *mic_payload;
558 const u8 *aad[] = { rsn->wpa_s->own_addr, sta->addr, cat };
559 const size_t aad_len[] = { ETH_ALEN, ETH_ALEN, ie - cat };
560 int ret = 0;
561 size_t len;
562
563 len = sizeof(*ampe);
564 if (cat[1] == PLINK_OPEN)
565 len += rsn->mgtk_len + WPA_KEY_RSC_LEN + 4;
566 if (cat[1] == PLINK_OPEN && rsn->igtk_len)
567 len += 2 + 6 + rsn->igtk_len;
568
569 if (2 + AES_BLOCK_SIZE + 2 + len > wpabuf_tailroom(buf)) {
570 wpa_printf(MSG_ERROR, "protect frame: buffer too small");
571 return -EINVAL;
572 }
573
574 ampe_ie = os_zalloc(2 + len);
575 if (!ampe_ie) {
576 wpa_printf(MSG_ERROR, "protect frame: out of memory");
577 return -ENOMEM;
578 }
579
580 /* IE: AMPE */
581 ampe_ie[0] = WLAN_EID_AMPE;
582 ampe_ie[1] = len;
583 ampe = (struct ieee80211_ampe_ie *) (ampe_ie + 2);
584
585 RSN_SELECTOR_PUT(ampe->selected_pairwise_suite,
586 RSN_CIPHER_SUITE_CCMP);
587 os_memcpy(ampe->local_nonce, sta->my_nonce, WPA_NONCE_LEN);
588 os_memcpy(ampe->peer_nonce, sta->peer_nonce, WPA_NONCE_LEN);
589
590 pos = (u8 *) (ampe + 1);
591 if (cat[1] != PLINK_OPEN)
592 goto skip_keys;
593
594 /* TODO: Key Replay Counter[8] optionally for
595 * Mesh Group Key Inform/Acknowledge frames */
596
597 /* TODO: static mgtk for now since we don't support rekeying! */
598 /*
599 * GTKdata[variable]:
600 * MGTK[variable] || Key RSC[8] || GTKExpirationTime[4]
601 */
602 os_memcpy(pos, rsn->mgtk, rsn->mgtk_len);
603 pos += rsn->mgtk_len;
604 wpa_drv_get_seqnum(rsn->wpa_s, NULL, rsn->mgtk_key_id, pos);
605 pos += WPA_KEY_RSC_LEN;
606 /* Use fixed GTKExpirationTime for now */
607 WPA_PUT_LE32(pos, 0xffffffff);
608 pos += 4;
609
610 /*
611 * IGTKdata[variable]:
612 * Key ID[2], IPN[6], IGTK[variable]
613 */
614 if (rsn->igtk_len) {
615 WPA_PUT_LE16(pos, rsn->igtk_key_id);
616 pos += 2;
617 wpa_drv_get_seqnum(rsn->wpa_s, NULL, rsn->igtk_key_id, pos);
618 pos += 6;
619 os_memcpy(pos, rsn->igtk, rsn->igtk_len);
620 }
621
622 skip_keys:
623 wpa_hexdump_key(MSG_DEBUG, "mesh: Plaintext AMPE element",
624 ampe_ie, 2 + len);
625
626 /* IE: MIC */
627 wpabuf_put_u8(buf, WLAN_EID_MIC);
628 wpabuf_put_u8(buf, AES_BLOCK_SIZE);
629 /* MIC field is output ciphertext */
630
631 /* encrypt after MIC */
632 mic_payload = wpabuf_put(buf, 2 + len + AES_BLOCK_SIZE);
633
634 if (aes_siv_encrypt(sta->aek, sizeof(sta->aek), ampe_ie, 2 + len, 3,
635 aad, aad_len, mic_payload)) {
636 wpa_printf(MSG_ERROR, "protect frame: failed to encrypt");
637 ret = -ENOMEM;
638 }
639
640 os_free(ampe_ie);
641
642 return ret;
643 }
644
645
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)646 int mesh_rsn_process_ampe(struct wpa_supplicant *wpa_s, struct sta_info *sta,
647 struct ieee802_11_elems *elems, const u8 *cat,
648 const u8 *chosen_pmk,
649 const u8 *start, size_t elems_len)
650 {
651 int ret = 0;
652 struct ieee80211_ampe_ie *ampe;
653 u8 null_nonce[WPA_NONCE_LEN] = {};
654 u8 ampe_eid;
655 u8 ampe_ie_len;
656 u8 *ampe_buf, *crypt = NULL, *pos, *end;
657 size_t crypt_len;
658 const u8 *aad[] = { sta->addr, wpa_s->own_addr, cat };
659 const size_t aad_len[] = { ETH_ALEN, ETH_ALEN,
660 elems->mic ? (elems->mic - 2) - cat : 0 };
661 size_t key_len;
662
663 if (!sta->sae) {
664 struct hostapd_data *hapd = wpa_s->ifmsh->bss[0];
665
666 if (!wpa_auth_pmksa_get(hapd->wpa_auth, sta->addr, NULL)) {
667 wpa_printf(MSG_INFO,
668 "Mesh RSN: SAE is not prepared yet");
669 return -1;
670 }
671 mesh_rsn_auth_sae_sta(wpa_s, sta);
672 }
673
674 if (chosen_pmk &&
675 (!sta->sae ||
676 os_memcmp(chosen_pmk, sta->sae->pmkid, PMKID_LEN) != 0)) {
677 wpa_msg(wpa_s, MSG_DEBUG,
678 "Mesh RSN: Invalid PMKID (Chosen PMK did not match calculated PMKID)");
679 return -1;
680 }
681
682 if (!elems->mic || elems->mic_len < AES_BLOCK_SIZE) {
683 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: missing mic ie");
684 return -1;
685 }
686
687 ampe_buf = (u8 *) elems->mic + elems->mic_len;
688 if ((int) elems_len < ampe_buf - start)
689 return -1;
690
691 crypt_len = elems_len - (elems->mic - start);
692 if (crypt_len < 2 + AES_BLOCK_SIZE) {
693 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: missing ampe ie");
694 return -1;
695 }
696
697 /* crypt is modified by siv_decrypt */
698 crypt = os_zalloc(crypt_len);
699 if (!crypt) {
700 wpa_printf(MSG_ERROR, "Mesh RSN: out of memory");
701 ret = -ENOMEM;
702 goto free;
703 }
704
705 os_memcpy(crypt, elems->mic, crypt_len);
706
707 if (aes_siv_decrypt(sta->aek, sizeof(sta->aek), crypt, crypt_len, 3,
708 aad, aad_len, ampe_buf)) {
709 wpa_printf(MSG_ERROR, "Mesh RSN: frame verification failed!");
710 ret = -2;
711 goto free;
712 }
713
714 crypt_len -= AES_BLOCK_SIZE;
715 wpa_hexdump_key(MSG_DEBUG, "mesh: Decrypted AMPE element",
716 ampe_buf, crypt_len);
717
718 ampe_eid = *ampe_buf++;
719 ampe_ie_len = *ampe_buf++;
720
721 if (ampe_eid != WLAN_EID_AMPE ||
722 (size_t) 2 + ampe_ie_len > crypt_len ||
723 ampe_ie_len < sizeof(struct ieee80211_ampe_ie)) {
724 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: invalid ampe ie");
725 ret = -1;
726 goto free;
727 }
728
729 ampe = (struct ieee80211_ampe_ie *) ampe_buf;
730 pos = (u8 *) (ampe + 1);
731 end = ampe_buf + ampe_ie_len;
732 if (os_memcmp(ampe->peer_nonce, null_nonce, WPA_NONCE_LEN) != 0 &&
733 os_memcmp(ampe->peer_nonce, sta->my_nonce, WPA_NONCE_LEN) != 0) {
734 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: invalid peer nonce");
735 ret = -1;
736 goto free;
737 }
738 os_memcpy(sta->peer_nonce, ampe->local_nonce,
739 sizeof(ampe->local_nonce));
740
741 /* TODO: Key Replay Counter[8] in Mesh Group Key Inform/Acknowledge
742 * frames */
743
744 /*
745 * GTKdata shall not be included in Mesh Peering Confirm. While the
746 * standard does not state the same about IGTKdata, that same constraint
747 * needs to apply for it. It makes no sense to include the keys in Mesh
748 * Peering Close frames either, so while the standard does not seem to
749 * have a shall statement for these, they are described without
750 * mentioning GTKdata.
751 *
752 * An earlier implementation used to add GTKdata to both Mesh Peering
753 * Open and Mesh Peering Confirm frames, so ignore the possibly present
754 * GTKdata frame without rejecting the frame as a backwards
755 * compatibility mechanism.
756 */
757 if (cat[1] != PLINK_OPEN) {
758 if (end > pos) {
759 wpa_hexdump_key(MSG_DEBUG,
760 "mesh: Ignore unexpected GTKdata(etc.) fields in the end of AMPE element in Mesh Peering Confirm/Close",
761 pos, end - pos);
762 }
763 goto free;
764 }
765
766 /*
767 * GTKdata[variable]:
768 * MGTK[variable] || Key RSC[8] || GTKExpirationTime[4]
769 */
770 sta->mgtk_key_id = 1; /* FIX: Where to get Key ID? */
771 key_len = wpa_cipher_key_len(wpa_s->mesh_rsn->group_cipher);
772 if ((int) key_len + WPA_KEY_RSC_LEN + 4 > end - pos) {
773 wpa_dbg(wpa_s, MSG_DEBUG, "mesh: Truncated AMPE element");
774 ret = -1;
775 goto free;
776 }
777 sta->mgtk_len = key_len;
778 os_memcpy(sta->mgtk, pos, sta->mgtk_len);
779 wpa_hexdump_key(MSG_DEBUG, "mesh: GTKdata - MGTK",
780 sta->mgtk, sta->mgtk_len);
781 pos += sta->mgtk_len;
782 wpa_hexdump(MSG_DEBUG, "mesh: GTKdata - MGTK - Key RSC",
783 pos, WPA_KEY_RSC_LEN);
784 os_memcpy(sta->mgtk_rsc, pos, sizeof(sta->mgtk_rsc));
785 pos += WPA_KEY_RSC_LEN;
786 wpa_printf(MSG_DEBUG,
787 "mesh: GTKdata - MGTK - GTKExpirationTime: %u seconds",
788 WPA_GET_LE32(pos));
789 pos += 4;
790
791 /*
792 * IGTKdata[variable]:
793 * Key ID[2], IPN[6], IGTK[variable]
794 */
795 key_len = wpa_cipher_key_len(wpa_s->mesh_rsn->mgmt_group_cipher);
796 if (end - pos >= (int) (2 + 6 + key_len)) {
797 sta->igtk_key_id = WPA_GET_LE16(pos);
798 wpa_printf(MSG_DEBUG, "mesh: IGTKdata - Key ID %u",
799 sta->igtk_key_id);
800 pos += 2;
801 os_memcpy(sta->igtk_rsc, pos, sizeof(sta->igtk_rsc));
802 wpa_hexdump(MSG_DEBUG, "mesh: IGTKdata - IPN",
803 sta->igtk_rsc, sizeof(sta->igtk_rsc));
804 pos += 6;
805 os_memcpy(sta->igtk, pos, key_len);
806 sta->igtk_len = key_len;
807 wpa_hexdump_key(MSG_DEBUG, "mesh: IGTKdata - IGTK",
808 sta->igtk, sta->igtk_len);
809 }
810
811 free:
812 os_free(crypt);
813 return ret;
814 }
815