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)77 static const u8 *auth_get_psk(void *ctx, const u8 *addr,
78 const u8 *p2p_dev_addr, const u8 *prev_psk)
79 {
80 struct mesh_rsn *mesh_rsn = ctx;
81 struct hostapd_data *hapd = mesh_rsn->wpa_s->ifmsh->bss[0];
82 struct sta_info *sta = ap_get_sta(hapd, addr);
83
84 wpa_printf(MSG_DEBUG, "AUTH: %s (addr=" MACSTR " prev_psk=%p)",
85 __func__, MAC2STR(addr), prev_psk);
86
87 if (sta && sta->auth_alg == WLAN_AUTH_SAE) {
88 if (!sta->sae || prev_psk)
89 return NULL;
90 return sta->sae->pmk;
91 }
92
93 return NULL;
94 }
95
96
auth_set_key(void * ctx,int vlan_id,enum wpa_alg alg,const u8 * addr,int idx,u8 * key,size_t key_len)97 static int auth_set_key(void *ctx, int vlan_id, enum wpa_alg alg,
98 const u8 *addr, int idx, u8 *key, size_t key_len)
99 {
100 struct mesh_rsn *mesh_rsn = ctx;
101 u8 seq[6];
102
103 os_memset(seq, 0, sizeof(seq));
104
105 if (addr) {
106 wpa_printf(MSG_DEBUG, "AUTH: %s(alg=%d addr=" MACSTR
107 " key_idx=%d)",
108 __func__, alg, MAC2STR(addr), idx);
109 } else {
110 wpa_printf(MSG_DEBUG, "AUTH: %s(alg=%d key_idx=%d)",
111 __func__, alg, idx);
112 }
113 wpa_hexdump_key(MSG_DEBUG, "AUTH: set_key - key", key, key_len);
114
115 return wpa_drv_set_key(mesh_rsn->wpa_s, alg, addr, idx,
116 1, seq, 6, key, key_len);
117 }
118
119
auth_start_ampe(void * ctx,const u8 * addr)120 static int auth_start_ampe(void *ctx, const u8 *addr)
121 {
122 struct mesh_rsn *mesh_rsn = ctx;
123 struct hostapd_data *hapd;
124 struct sta_info *sta;
125
126 if (mesh_rsn->wpa_s->current_ssid->mode != WPAS_MODE_MESH)
127 return -1;
128
129 hapd = mesh_rsn->wpa_s->ifmsh->bss[0];
130 sta = ap_get_sta(hapd, addr);
131 if (sta)
132 eloop_cancel_timeout(mesh_auth_timer, mesh_rsn->wpa_s, sta);
133
134 mesh_mpm_auth_peer(mesh_rsn->wpa_s, addr);
135 return 0;
136 }
137
138
__mesh_rsn_auth_init(struct mesh_rsn * rsn,const u8 * addr,enum mfp_options ieee80211w)139 static int __mesh_rsn_auth_init(struct mesh_rsn *rsn, const u8 *addr,
140 enum mfp_options ieee80211w)
141 {
142 struct wpa_auth_config conf;
143 static const struct wpa_auth_callbacks cb = {
144 .logger = auth_logger,
145 .get_psk = auth_get_psk,
146 .set_key = auth_set_key,
147 .start_ampe = auth_start_ampe,
148 };
149 u8 seq[6] = {};
150
151 wpa_printf(MSG_DEBUG, "AUTH: Initializing group state machine");
152
153 os_memset(&conf, 0, sizeof(conf));
154 conf.wpa = WPA_PROTO_RSN;
155 conf.wpa_key_mgmt = WPA_KEY_MGMT_SAE;
156 conf.wpa_pairwise = rsn->pairwise_cipher;
157 conf.rsn_pairwise = rsn->pairwise_cipher;
158 conf.wpa_group = rsn->group_cipher;
159 conf.eapol_version = 0;
160 conf.wpa_group_rekey = -1;
161 conf.wpa_group_update_count = 4;
162 conf.wpa_pairwise_update_count = 4;
163 #ifdef CONFIG_IEEE80211W
164 conf.ieee80211w = ieee80211w;
165 if (ieee80211w != NO_MGMT_FRAME_PROTECTION)
166 conf.group_mgmt_cipher = rsn->mgmt_group_cipher;
167 #endif /* CONFIG_IEEE80211W */
168
169 rsn->auth = wpa_init(addr, &conf, &cb, rsn);
170 if (rsn->auth == NULL) {
171 wpa_printf(MSG_DEBUG, "AUTH: wpa_init() failed");
172 return -1;
173 }
174
175 /* TODO: support rekeying */
176 rsn->mgtk_len = wpa_cipher_key_len(conf.wpa_group);
177 if (random_get_bytes(rsn->mgtk, rsn->mgtk_len) < 0)
178 return -1;
179 rsn->mgtk_key_id = 1;
180
181 #ifdef CONFIG_IEEE80211W
182 if (ieee80211w != NO_MGMT_FRAME_PROTECTION) {
183 rsn->igtk_len = wpa_cipher_key_len(conf.group_mgmt_cipher);
184 if (random_get_bytes(rsn->igtk, rsn->igtk_len) < 0)
185 return -1;
186 rsn->igtk_key_id = 4;
187
188 /* group mgmt */
189 wpa_hexdump_key(MSG_DEBUG, "mesh: Own TX IGTK",
190 rsn->igtk, rsn->igtk_len);
191 wpa_drv_set_key(rsn->wpa_s,
192 wpa_cipher_to_alg(rsn->mgmt_group_cipher), NULL,
193 rsn->igtk_key_id, 1,
194 seq, sizeof(seq), rsn->igtk, rsn->igtk_len);
195 }
196 #endif /* CONFIG_IEEE80211W */
197
198 /* group privacy / data frames */
199 wpa_hexdump_key(MSG_DEBUG, "mesh: Own TX MGTK",
200 rsn->mgtk, rsn->mgtk_len);
201 wpa_drv_set_key(rsn->wpa_s, wpa_cipher_to_alg(rsn->group_cipher), NULL,
202 rsn->mgtk_key_id, 1, seq, sizeof(seq),
203 rsn->mgtk, rsn->mgtk_len);
204
205 return 0;
206 }
207
208
mesh_rsn_deinit(struct mesh_rsn * rsn)209 static void mesh_rsn_deinit(struct mesh_rsn *rsn)
210 {
211 os_memset(rsn->mgtk, 0, sizeof(rsn->mgtk));
212 rsn->mgtk_len = 0;
213 os_memset(rsn->igtk, 0, sizeof(rsn->igtk));
214 rsn->igtk_len = 0;
215 if (rsn->auth)
216 wpa_deinit(rsn->auth);
217 }
218
219
mesh_rsn_auth_init(struct wpa_supplicant * wpa_s,struct mesh_conf * conf)220 struct mesh_rsn *mesh_rsn_auth_init(struct wpa_supplicant *wpa_s,
221 struct mesh_conf *conf)
222 {
223 struct mesh_rsn *mesh_rsn;
224 struct hostapd_data *bss = wpa_s->ifmsh->bss[0];
225 const u8 *ie;
226 size_t ie_len;
227 #ifdef CONFIG_PMKSA_CACHE_EXTERNAL
228 struct external_pmksa_cache *entry;
229 #endif /* CONFIG_PMKSA_CACHE_EXTERNAL */
230
231 mesh_rsn = os_zalloc(sizeof(*mesh_rsn));
232 if (mesh_rsn == NULL)
233 return NULL;
234 mesh_rsn->wpa_s = wpa_s;
235 mesh_rsn->pairwise_cipher = conf->pairwise_cipher;
236 mesh_rsn->group_cipher = conf->group_cipher;
237 mesh_rsn->mgmt_group_cipher = conf->mgmt_group_cipher;
238
239 if (__mesh_rsn_auth_init(mesh_rsn, wpa_s->own_addr,
240 conf->ieee80211w) < 0) {
241 mesh_rsn_deinit(mesh_rsn);
242 os_free(mesh_rsn);
243 return NULL;
244 }
245
246 bss->wpa_auth = mesh_rsn->auth;
247
248 #ifdef CONFIG_PMKSA_CACHE_EXTERNAL
249 while ((entry = dl_list_last(&wpa_s->mesh_external_pmksa_cache,
250 struct external_pmksa_cache,
251 list)) != NULL) {
252 int ret;
253
254 ret = wpa_auth_pmksa_add_entry(bss->wpa_auth,
255 entry->pmksa_cache);
256 dl_list_del(&entry->list);
257 os_free(entry);
258
259 if (ret < 0)
260 return NULL;
261 }
262 #endif /* CONFIG_PMKSA_CACHE_EXTERNAL */
263
264 ie = wpa_auth_get_wpa_ie(mesh_rsn->auth, &ie_len);
265 conf->rsn_ie = (u8 *) ie;
266 conf->rsn_ie_len = ie_len;
267
268 wpa_supplicant_rsn_supp_set_config(wpa_s, wpa_s->current_ssid);
269
270 return mesh_rsn;
271 }
272
273
index_within_array(const int * array,int idx)274 static int index_within_array(const int *array, int idx)
275 {
276 int i;
277
278 for (i = 0; i < idx; i++) {
279 if (array[i] == -1)
280 return 0;
281 }
282
283 return 1;
284 }
285
286
mesh_rsn_sae_group(struct wpa_supplicant * wpa_s,struct sae_data * sae)287 static int mesh_rsn_sae_group(struct wpa_supplicant *wpa_s,
288 struct sae_data *sae)
289 {
290 int *groups = wpa_s->ifmsh->bss[0]->conf->sae_groups;
291
292 /* Configuration may have changed, so validate current index */
293 if (!index_within_array(groups, wpa_s->mesh_rsn->sae_group_index))
294 return -1;
295
296 for (;;) {
297 int group = groups[wpa_s->mesh_rsn->sae_group_index];
298
299 if (group <= 0)
300 break;
301 if (sae_set_group(sae, group) == 0) {
302 wpa_dbg(wpa_s, MSG_DEBUG, "SME: Selected SAE group %d",
303 sae->group);
304 return 0;
305 }
306 wpa_s->mesh_rsn->sae_group_index++;
307 }
308
309 return -1;
310 }
311
312
mesh_rsn_build_sae_commit(struct wpa_supplicant * wpa_s,struct wpa_ssid * ssid,struct sta_info * sta)313 static int mesh_rsn_build_sae_commit(struct wpa_supplicant *wpa_s,
314 struct wpa_ssid *ssid,
315 struct sta_info *sta)
316 {
317 if (ssid->passphrase == NULL) {
318 wpa_msg(wpa_s, MSG_DEBUG, "SAE: No password available");
319 return -1;
320 }
321
322 if (mesh_rsn_sae_group(wpa_s, sta->sae) < 0) {
323 wpa_msg(wpa_s, MSG_DEBUG, "SAE: Failed to select group");
324 return -1;
325 }
326
327 return sae_prepare_commit(wpa_s->own_addr, sta->addr,
328 (u8 *) ssid->passphrase,
329 os_strlen(ssid->passphrase), sta->sae);
330 }
331
332
333 /* initiate new SAE authentication with sta */
mesh_rsn_auth_sae_sta(struct wpa_supplicant * wpa_s,struct sta_info * sta)334 int mesh_rsn_auth_sae_sta(struct wpa_supplicant *wpa_s,
335 struct sta_info *sta)
336 {
337 struct hostapd_data *hapd = wpa_s->ifmsh->bss[0];
338 struct wpa_ssid *ssid = wpa_s->current_ssid;
339 struct rsn_pmksa_cache_entry *pmksa;
340 unsigned int rnd;
341 int ret;
342
343 if (!ssid) {
344 wpa_msg(wpa_s, MSG_DEBUG,
345 "AUTH: No current_ssid known to initiate new SAE");
346 return -1;
347 }
348
349 if (!sta->sae) {
350 sta->sae = os_zalloc(sizeof(*sta->sae));
351 if (sta->sae == NULL)
352 return -1;
353 }
354
355 pmksa = wpa_auth_pmksa_get(hapd->wpa_auth, sta->addr, NULL);
356 if (pmksa) {
357 if (!sta->wpa_sm)
358 sta->wpa_sm = wpa_auth_sta_init(hapd->wpa_auth,
359 sta->addr, NULL);
360 if (!sta->wpa_sm) {
361 wpa_printf(MSG_ERROR,
362 "mesh: Failed to initialize RSN state machine");
363 return -1;
364 }
365
366 wpa_printf(MSG_DEBUG,
367 "AUTH: Mesh PMKSA cache entry found for " MACSTR
368 " - try to use PMKSA caching instead of new SAE authentication",
369 MAC2STR(sta->addr));
370 wpa_auth_pmksa_set_to_sm(pmksa, sta->wpa_sm, hapd->wpa_auth,
371 sta->sae->pmkid, sta->sae->pmk);
372 sae_accept_sta(hapd, sta);
373 sta->mesh_sae_pmksa_caching = 1;
374 return 0;
375 }
376 sta->mesh_sae_pmksa_caching = 0;
377
378 if (mesh_rsn_build_sae_commit(wpa_s, ssid, sta))
379 return -1;
380
381 wpa_msg(wpa_s, MSG_DEBUG,
382 "AUTH: started authentication with SAE peer: " MACSTR,
383 MAC2STR(sta->addr));
384
385 ret = auth_sae_init_committed(hapd, sta);
386 if (ret)
387 return ret;
388
389 eloop_cancel_timeout(mesh_auth_timer, wpa_s, sta);
390 rnd = rand() % MESH_AUTH_TIMEOUT;
391 eloop_register_timeout(MESH_AUTH_TIMEOUT + rnd, 0, mesh_auth_timer,
392 wpa_s, sta);
393 return 0;
394 }
395
396
mesh_rsn_get_pmkid(struct mesh_rsn * rsn,struct sta_info * sta,u8 * pmkid)397 void mesh_rsn_get_pmkid(struct mesh_rsn *rsn, struct sta_info *sta, u8 *pmkid)
398 {
399 os_memcpy(pmkid, sta->sae->pmkid, SAE_PMKID_LEN);
400 }
401
402
403 static void
mesh_rsn_derive_aek(struct mesh_rsn * rsn,struct sta_info * sta)404 mesh_rsn_derive_aek(struct mesh_rsn *rsn, struct sta_info *sta)
405 {
406 u8 *myaddr = rsn->wpa_s->own_addr;
407 u8 *peer = sta->addr;
408 u8 *addr1, *addr2;
409 u8 context[RSN_SELECTOR_LEN + 2 * ETH_ALEN], *ptr = context;
410
411 /*
412 * AEK = KDF-Hash-256(PMK, "AEK Derivation", Selected AKM Suite ||
413 * min(localMAC, peerMAC) || max(localMAC, peerMAC))
414 */
415 /* Selected AKM Suite: SAE */
416 RSN_SELECTOR_PUT(ptr, RSN_AUTH_KEY_MGMT_SAE);
417 ptr += RSN_SELECTOR_LEN;
418
419 if (os_memcmp(myaddr, peer, ETH_ALEN) < 0) {
420 addr1 = myaddr;
421 addr2 = peer;
422 } else {
423 addr1 = peer;
424 addr2 = myaddr;
425 }
426 os_memcpy(ptr, addr1, ETH_ALEN);
427 ptr += ETH_ALEN;
428 os_memcpy(ptr, addr2, ETH_ALEN);
429
430 sha256_prf(sta->sae->pmk, sizeof(sta->sae->pmk), "AEK Derivation",
431 context, sizeof(context), sta->aek, sizeof(sta->aek));
432 }
433
434
435 /* derive mesh temporal key from pmk */
mesh_rsn_derive_mtk(struct wpa_supplicant * wpa_s,struct sta_info * sta)436 int mesh_rsn_derive_mtk(struct wpa_supplicant *wpa_s, struct sta_info *sta)
437 {
438 u8 *ptr;
439 u8 *min, *max;
440 u8 *myaddr = wpa_s->own_addr;
441 u8 *peer = sta->addr;
442 u8 context[2 * WPA_NONCE_LEN + 2 * 2 + RSN_SELECTOR_LEN + 2 * ETH_ALEN];
443
444 /*
445 * MTK = KDF-Hash-Length(PMK, "Temporal Key Derivation", min(localNonce,
446 * peerNonce) || max(localNonce, peerNonce) || min(localLinkID,
447 * peerLinkID) || max(localLinkID, peerLinkID) || Selected AKM Suite ||
448 * min(localMAC, peerMAC) || max(localMAC, peerMAC))
449 */
450 ptr = context;
451 if (os_memcmp(sta->my_nonce, sta->peer_nonce, WPA_NONCE_LEN) < 0) {
452 min = sta->my_nonce;
453 max = sta->peer_nonce;
454 } else {
455 min = sta->peer_nonce;
456 max = sta->my_nonce;
457 }
458 os_memcpy(ptr, min, WPA_NONCE_LEN);
459 ptr += WPA_NONCE_LEN;
460 os_memcpy(ptr, max, WPA_NONCE_LEN);
461 ptr += WPA_NONCE_LEN;
462
463 if (sta->my_lid < sta->peer_lid) {
464 WPA_PUT_LE16(ptr, sta->my_lid);
465 ptr += 2;
466 WPA_PUT_LE16(ptr, sta->peer_lid);
467 ptr += 2;
468 } else {
469 WPA_PUT_LE16(ptr, sta->peer_lid);
470 ptr += 2;
471 WPA_PUT_LE16(ptr, sta->my_lid);
472 ptr += 2;
473 }
474
475 /* Selected AKM Suite: SAE */
476 RSN_SELECTOR_PUT(ptr, RSN_AUTH_KEY_MGMT_SAE);
477 ptr += RSN_SELECTOR_LEN;
478
479 if (os_memcmp(myaddr, peer, ETH_ALEN) < 0) {
480 min = myaddr;
481 max = peer;
482 } else {
483 min = peer;
484 max = myaddr;
485 }
486 os_memcpy(ptr, min, ETH_ALEN);
487 ptr += ETH_ALEN;
488 os_memcpy(ptr, max, ETH_ALEN);
489
490 sta->mtk_len = wpa_cipher_key_len(wpa_s->mesh_rsn->pairwise_cipher);
491 sha256_prf(sta->sae->pmk, SAE_PMK_LEN,
492 "Temporal Key Derivation", context, sizeof(context),
493 sta->mtk, sta->mtk_len);
494 return 0;
495 }
496
497
mesh_rsn_init_ampe_sta(struct wpa_supplicant * wpa_s,struct sta_info * sta)498 void mesh_rsn_init_ampe_sta(struct wpa_supplicant *wpa_s, struct sta_info *sta)
499 {
500 if (random_get_bytes(sta->my_nonce, WPA_NONCE_LEN) < 0) {
501 wpa_printf(MSG_INFO, "mesh: Failed to derive random nonce");
502 /* TODO: How to handle this more cleanly? */
503 }
504 os_memset(sta->peer_nonce, 0, WPA_NONCE_LEN);
505 mesh_rsn_derive_aek(wpa_s->mesh_rsn, sta);
506 }
507
508
509 /* insert AMPE and encrypted MIC at @ie.
510 * @mesh_rsn: mesh RSN context
511 * @sta: STA we're sending to
512 * @cat: pointer to category code in frame header.
513 * @buf: wpabuf to add encrypted AMPE and MIC to.
514 * */
mesh_rsn_protect_frame(struct mesh_rsn * rsn,struct sta_info * sta,const u8 * cat,struct wpabuf * buf)515 int mesh_rsn_protect_frame(struct mesh_rsn *rsn, struct sta_info *sta,
516 const u8 *cat, struct wpabuf *buf)
517 {
518 struct ieee80211_ampe_ie *ampe;
519 u8 const *ie = wpabuf_head_u8(buf) + wpabuf_len(buf);
520 u8 *ampe_ie, *pos, *mic_payload;
521 const u8 *aad[] = { rsn->wpa_s->own_addr, sta->addr, cat };
522 const size_t aad_len[] = { ETH_ALEN, ETH_ALEN, ie - cat };
523 int ret = 0;
524 size_t len;
525
526 len = sizeof(*ampe);
527 if (cat[1] == PLINK_OPEN)
528 len += rsn->mgtk_len + WPA_KEY_RSC_LEN + 4;
529 #ifdef CONFIG_IEEE80211W
530 if (cat[1] == PLINK_OPEN && rsn->igtk_len)
531 len += 2 + 6 + rsn->igtk_len;
532 #endif /* CONFIG_IEEE80211W */
533
534 if (2 + AES_BLOCK_SIZE + 2 + len > wpabuf_tailroom(buf)) {
535 wpa_printf(MSG_ERROR, "protect frame: buffer too small");
536 return -EINVAL;
537 }
538
539 ampe_ie = os_zalloc(2 + len);
540 if (!ampe_ie) {
541 wpa_printf(MSG_ERROR, "protect frame: out of memory");
542 return -ENOMEM;
543 }
544
545 /* IE: AMPE */
546 ampe_ie[0] = WLAN_EID_AMPE;
547 ampe_ie[1] = len;
548 ampe = (struct ieee80211_ampe_ie *) (ampe_ie + 2);
549
550 RSN_SELECTOR_PUT(ampe->selected_pairwise_suite,
551 RSN_CIPHER_SUITE_CCMP);
552 os_memcpy(ampe->local_nonce, sta->my_nonce, WPA_NONCE_LEN);
553 os_memcpy(ampe->peer_nonce, sta->peer_nonce, WPA_NONCE_LEN);
554
555 pos = (u8 *) (ampe + 1);
556 if (cat[1] != PLINK_OPEN)
557 goto skip_keys;
558
559 /* TODO: Key Replay Counter[8] optionally for
560 * Mesh Group Key Inform/Acknowledge frames */
561
562 /* TODO: static mgtk for now since we don't support rekeying! */
563 /*
564 * GTKdata[variable]:
565 * MGTK[variable] || Key RSC[8] || GTKExpirationTime[4]
566 */
567 os_memcpy(pos, rsn->mgtk, rsn->mgtk_len);
568 pos += rsn->mgtk_len;
569 wpa_drv_get_seqnum(rsn->wpa_s, NULL, rsn->mgtk_key_id, pos);
570 pos += WPA_KEY_RSC_LEN;
571 /* Use fixed GTKExpirationTime for now */
572 WPA_PUT_LE32(pos, 0xffffffff);
573 pos += 4;
574
575 #ifdef CONFIG_IEEE80211W
576 /*
577 * IGTKdata[variable]:
578 * Key ID[2], IPN[6], IGTK[variable]
579 */
580 if (rsn->igtk_len) {
581 WPA_PUT_LE16(pos, rsn->igtk_key_id);
582 pos += 2;
583 wpa_drv_get_seqnum(rsn->wpa_s, NULL, rsn->igtk_key_id, pos);
584 pos += 6;
585 os_memcpy(pos, rsn->igtk, rsn->igtk_len);
586 }
587 #endif /* CONFIG_IEEE80211W */
588
589 skip_keys:
590 wpa_hexdump_key(MSG_DEBUG, "mesh: Plaintext AMPE element",
591 ampe_ie, 2 + len);
592
593 /* IE: MIC */
594 wpabuf_put_u8(buf, WLAN_EID_MIC);
595 wpabuf_put_u8(buf, AES_BLOCK_SIZE);
596 /* MIC field is output ciphertext */
597
598 /* encrypt after MIC */
599 mic_payload = wpabuf_put(buf, 2 + len + AES_BLOCK_SIZE);
600
601 if (aes_siv_encrypt(sta->aek, sizeof(sta->aek), ampe_ie, 2 + len, 3,
602 aad, aad_len, mic_payload)) {
603 wpa_printf(MSG_ERROR, "protect frame: failed to encrypt");
604 ret = -ENOMEM;
605 }
606
607 os_free(ampe_ie);
608
609 return ret;
610 }
611
612
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)613 int mesh_rsn_process_ampe(struct wpa_supplicant *wpa_s, struct sta_info *sta,
614 struct ieee802_11_elems *elems, const u8 *cat,
615 const u8 *chosen_pmk,
616 const u8 *start, size_t elems_len)
617 {
618 int ret = 0;
619 struct ieee80211_ampe_ie *ampe;
620 u8 null_nonce[WPA_NONCE_LEN] = {};
621 u8 ampe_eid;
622 u8 ampe_ie_len;
623 u8 *ampe_buf, *crypt = NULL, *pos, *end;
624 size_t crypt_len;
625 const u8 *aad[] = { sta->addr, wpa_s->own_addr, cat };
626 const size_t aad_len[] = { ETH_ALEN, ETH_ALEN,
627 (elems->mic - 2) - cat };
628 size_t key_len;
629
630 if (!sta->sae) {
631 struct hostapd_data *hapd = wpa_s->ifmsh->bss[0];
632
633 if (!wpa_auth_pmksa_get(hapd->wpa_auth, sta->addr, NULL)) {
634 wpa_printf(MSG_INFO,
635 "Mesh RSN: SAE is not prepared yet");
636 return -1;
637 }
638 mesh_rsn_auth_sae_sta(wpa_s, sta);
639 }
640
641 if (chosen_pmk && os_memcmp(chosen_pmk, sta->sae->pmkid, PMKID_LEN)) {
642 wpa_msg(wpa_s, MSG_DEBUG,
643 "Mesh RSN: Invalid PMKID (Chosen PMK did not match calculated PMKID)");
644 return -1;
645 }
646
647 if (!elems->mic || elems->mic_len < AES_BLOCK_SIZE) {
648 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: missing mic ie");
649 return -1;
650 }
651
652 ampe_buf = (u8 *) elems->mic + elems->mic_len;
653 if ((int) elems_len < ampe_buf - start)
654 return -1;
655
656 crypt_len = elems_len - (elems->mic - start);
657 if (crypt_len < 2 + AES_BLOCK_SIZE) {
658 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: missing ampe ie");
659 return -1;
660 }
661
662 /* crypt is modified by siv_decrypt */
663 crypt = os_zalloc(crypt_len);
664 if (!crypt) {
665 wpa_printf(MSG_ERROR, "Mesh RSN: out of memory");
666 ret = -ENOMEM;
667 goto free;
668 }
669
670 os_memcpy(crypt, elems->mic, crypt_len);
671
672 if (aes_siv_decrypt(sta->aek, sizeof(sta->aek), crypt, crypt_len, 3,
673 aad, aad_len, ampe_buf)) {
674 wpa_printf(MSG_ERROR, "Mesh RSN: frame verification failed!");
675 ret = -2;
676 goto free;
677 }
678
679 crypt_len -= AES_BLOCK_SIZE;
680 wpa_hexdump_key(MSG_DEBUG, "mesh: Decrypted AMPE element",
681 ampe_buf, crypt_len);
682
683 ampe_eid = *ampe_buf++;
684 ampe_ie_len = *ampe_buf++;
685
686 if (ampe_eid != WLAN_EID_AMPE ||
687 (size_t) 2 + ampe_ie_len > crypt_len ||
688 ampe_ie_len < sizeof(struct ieee80211_ampe_ie)) {
689 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: invalid ampe ie");
690 ret = -1;
691 goto free;
692 }
693
694 ampe = (struct ieee80211_ampe_ie *) ampe_buf;
695 pos = (u8 *) (ampe + 1);
696 end = ampe_buf + ampe_ie_len;
697 if (os_memcmp(ampe->peer_nonce, null_nonce, WPA_NONCE_LEN) != 0 &&
698 os_memcmp(ampe->peer_nonce, sta->my_nonce, WPA_NONCE_LEN) != 0) {
699 wpa_msg(wpa_s, MSG_DEBUG, "Mesh RSN: invalid peer nonce");
700 ret = -1;
701 goto free;
702 }
703 os_memcpy(sta->peer_nonce, ampe->local_nonce,
704 sizeof(ampe->local_nonce));
705
706 /* TODO: Key Replay Counter[8] in Mesh Group Key Inform/Acknowledge
707 * frames */
708
709 /*
710 * GTKdata shall not be included in Mesh Peering Confirm. While the
711 * standard does not state the same about IGTKdata, that same constraint
712 * needs to apply for it. It makes no sense to include the keys in Mesh
713 * Peering Close frames either, so while the standard does not seem to
714 * have a shall statement for these, they are described without
715 * mentioning GTKdata.
716 *
717 * An earlier implementation used to add GTKdata to both Mesh Peering
718 * Open and Mesh Peering Confirm frames, so ignore the possibly present
719 * GTKdata frame without rejecting the frame as a backwards
720 * compatibility mechanism.
721 */
722 if (cat[1] != PLINK_OPEN) {
723 if (end > pos) {
724 wpa_hexdump_key(MSG_DEBUG,
725 "mesh: Ignore unexpected GTKdata(etc.) fields in the end of AMPE element in Mesh Peering Confirm/Close",
726 pos, end - pos);
727 }
728 goto free;
729 }
730
731 /*
732 * GTKdata[variable]:
733 * MGTK[variable] || Key RSC[8] || GTKExpirationTime[4]
734 */
735 sta->mgtk_key_id = 1; /* FIX: Where to get Key ID? */
736 key_len = wpa_cipher_key_len(wpa_s->mesh_rsn->group_cipher);
737 if ((int) key_len + WPA_KEY_RSC_LEN + 4 > end - pos) {
738 wpa_dbg(wpa_s, MSG_DEBUG, "mesh: Truncated AMPE element");
739 ret = -1;
740 goto free;
741 }
742 sta->mgtk_len = key_len;
743 os_memcpy(sta->mgtk, pos, sta->mgtk_len);
744 wpa_hexdump_key(MSG_DEBUG, "mesh: GTKdata - MGTK",
745 sta->mgtk, sta->mgtk_len);
746 pos += sta->mgtk_len;
747 wpa_hexdump(MSG_DEBUG, "mesh: GTKdata - MGTK - Key RSC",
748 pos, WPA_KEY_RSC_LEN);
749 os_memcpy(sta->mgtk_rsc, pos, sizeof(sta->mgtk_rsc));
750 pos += WPA_KEY_RSC_LEN;
751 wpa_printf(MSG_DEBUG,
752 "mesh: GTKdata - MGTK - GTKExpirationTime: %u seconds",
753 WPA_GET_LE32(pos));
754 pos += 4;
755
756 #ifdef CONFIG_IEEE80211W
757 /*
758 * IGTKdata[variable]:
759 * Key ID[2], IPN[6], IGTK[variable]
760 */
761 key_len = wpa_cipher_key_len(wpa_s->mesh_rsn->mgmt_group_cipher);
762 if (end - pos >= (int) (2 + 6 + key_len)) {
763 sta->igtk_key_id = WPA_GET_LE16(pos);
764 wpa_printf(MSG_DEBUG, "mesh: IGTKdata - Key ID %u",
765 sta->igtk_key_id);
766 pos += 2;
767 os_memcpy(sta->igtk_rsc, pos, sizeof(sta->igtk_rsc));
768 wpa_hexdump(MSG_DEBUG, "mesh: IGTKdata - IPN",
769 sta->igtk_rsc, sizeof(sta->igtk_rsc));
770 pos += 6;
771 os_memcpy(sta->igtk, pos, key_len);
772 sta->igtk_len = key_len;
773 wpa_hexdump_key(MSG_DEBUG, "mesh: IGTKdata - IGTK",
774 sta->igtk, sta->igtk_len);
775 }
776 #endif /* CONFIG_IEEE80211W */
777
778 free:
779 os_free(crypt);
780 return ret;
781 }
782