1 /*
2 * RSN pre-authentication (supplicant)
3 * Copyright (c) 2003-2015, Jouni Malinen <j@w1.fi>
4 *
5 * This software may be distributed under the terms of the BSD license.
6 * See README for more details.
7 */
8
9 #include "includes.h"
10
11 #include "common.h"
12 #include "wpa.h"
13 #include "eloop.h"
14 #include "l2_packet/l2_packet.h"
15 #include "eapol_supp/eapol_supp_sm.h"
16 #include "preauth.h"
17 #include "pmksa_cache.h"
18 #include "wpa_i.h"
19
20
21 #if defined(IEEE8021X_EAPOL) && !defined(CONFIG_NO_WPA)
22
23 #define PMKID_CANDIDATE_PRIO_SCAN 1000
24
25
26 struct rsn_pmksa_candidate {
27 struct dl_list list;
28 u8 bssid[ETH_ALEN];
29 int priority;
30 };
31
32
33 /**
34 * pmksa_candidate_free - Free all entries in PMKSA candidate list
35 * @sm: Pointer to WPA state machine data from wpa_sm_init()
36 */
pmksa_candidate_free(struct wpa_sm * sm)37 void pmksa_candidate_free(struct wpa_sm *sm)
38 {
39 struct rsn_pmksa_candidate *entry, *n;
40
41 if (sm == NULL)
42 return;
43
44 dl_list_for_each_safe(entry, n, &sm->pmksa_candidates,
45 struct rsn_pmksa_candidate, list) {
46 dl_list_del(&entry->list);
47 os_free(entry);
48 }
49 }
50
51
rsn_preauth_key_mgmt(int akmp)52 static int rsn_preauth_key_mgmt(int akmp)
53 {
54 return !!(akmp & (WPA_KEY_MGMT_IEEE8021X |
55 WPA_KEY_MGMT_IEEE8021X_SHA256 |
56 WPA_KEY_MGMT_IEEE8021X_SUITE_B |
57 WPA_KEY_MGMT_IEEE8021X_SUITE_B_192 |
58 WPA_KEY_MGMT_IEEE8021X_SHA384));
59 }
60
61
rsn_preauth_receive(void * ctx,const u8 * src_addr,const u8 * buf,size_t len)62 static void rsn_preauth_receive(void *ctx, const u8 *src_addr,
63 const u8 *buf, size_t len)
64 {
65 struct wpa_sm *sm = ctx;
66
67 wpa_printf(MSG_DEBUG, "RX pre-auth from " MACSTR, MAC2STR(src_addr));
68 wpa_hexdump(MSG_MSGDUMP, "RX pre-auth", buf, len);
69
70 if (sm->preauth_eapol == NULL ||
71 is_zero_ether_addr(sm->preauth_bssid) ||
72 !ether_addr_equal(sm->preauth_bssid, src_addr)) {
73 wpa_printf(MSG_WARNING, "RSN pre-auth frame received from "
74 "unexpected source " MACSTR " - dropped",
75 MAC2STR(src_addr));
76 return;
77 }
78
79 eapol_sm_rx_eapol(sm->preauth_eapol, src_addr, buf, len,
80 FRAME_ENCRYPTION_UNKNOWN);
81 }
82
83
rsn_preauth_eapol_cb(struct eapol_sm * eapol,enum eapol_supp_result result,void * ctx)84 static void rsn_preauth_eapol_cb(struct eapol_sm *eapol,
85 enum eapol_supp_result result,
86 void *ctx)
87 {
88 struct wpa_sm *sm = ctx;
89 u8 pmk[PMK_LEN];
90
91 if (result == EAPOL_SUPP_RESULT_SUCCESS) {
92 int res, pmk_len;
93 pmk_len = PMK_LEN;
94 res = eapol_sm_get_key(eapol, pmk, PMK_LEN);
95 if (res) {
96 /*
97 * EAP-LEAP is an exception from other EAP methods: it
98 * uses only 16-byte PMK.
99 */
100 res = eapol_sm_get_key(eapol, pmk, 16);
101 pmk_len = 16;
102 }
103 if (res == 0) {
104 wpa_hexdump_key(MSG_DEBUG, "RSN: PMK from pre-auth",
105 pmk, pmk_len);
106 sm->pmk_len = pmk_len;
107 pmksa_cache_add(sm->pmksa, pmk, pmk_len, NULL,
108 NULL, 0,
109 sm->preauth_bssid, sm->own_addr,
110 sm->network_ctx,
111 WPA_KEY_MGMT_IEEE8021X, NULL);
112 } else {
113 wpa_msg(sm->ctx->msg_ctx, MSG_INFO,
114 "RSN: failed to get master session key from "
115 "pre-auth EAPOL state machines");
116 result = EAPOL_SUPP_RESULT_FAILURE;
117 }
118 }
119
120 wpa_msg(sm->ctx->msg_ctx, MSG_INFO, "RSN: pre-authentication with "
121 MACSTR " %s", MAC2STR(sm->preauth_bssid),
122 result == EAPOL_SUPP_RESULT_SUCCESS ? "completed successfully" :
123 "failed");
124
125 rsn_preauth_deinit(sm);
126 rsn_preauth_candidate_process(sm);
127 }
128
129
rsn_preauth_timeout(void * eloop_ctx,void * timeout_ctx)130 static void rsn_preauth_timeout(void *eloop_ctx, void *timeout_ctx)
131 {
132 struct wpa_sm *sm = eloop_ctx;
133
134 wpa_msg(sm->ctx->msg_ctx, MSG_INFO, "RSN: pre-authentication with "
135 MACSTR " timed out", MAC2STR(sm->preauth_bssid));
136 rsn_preauth_deinit(sm);
137 rsn_preauth_candidate_process(sm);
138 }
139
140
rsn_preauth_eapol_send(void * ctx,int type,const u8 * buf,size_t len)141 static int rsn_preauth_eapol_send(void *ctx, int type, const u8 *buf,
142 size_t len)
143 {
144 struct wpa_sm *sm = ctx;
145 u8 *msg;
146 size_t msglen;
147 int res;
148
149 /* TODO: could add l2_packet_sendmsg that allows fragments to avoid
150 * extra copy here */
151
152 if (sm->l2_preauth == NULL)
153 return -1;
154
155 msg = wpa_sm_alloc_eapol(sm, type, buf, len, &msglen, NULL);
156 if (msg == NULL)
157 return -1;
158
159 wpa_hexdump(MSG_MSGDUMP, "TX EAPOL (preauth)", msg, msglen);
160 res = l2_packet_send(sm->l2_preauth, sm->preauth_bssid,
161 ETH_P_RSN_PREAUTH, msg, msglen);
162 os_free(msg);
163 return res;
164 }
165
166
167 /**
168 * rsn_preauth_init - Start new RSN pre-authentication
169 * @sm: Pointer to WPA state machine data from wpa_sm_init()
170 * @dst: Authenticator address (BSSID) with which to preauthenticate
171 * @eap_conf: Current EAP configuration
172 * Returns: 0 on success, -1 on another pre-authentication is in progress,
173 * -2 on layer 2 packet initialization failure, -3 on EAPOL state machine
174 * initialization failure, -4 on memory allocation failure
175 *
176 * This function request an RSN pre-authentication with a given destination
177 * address. This is usually called for PMKSA candidates found from scan results
178 * or from driver reports. In addition, ctrl_iface PREAUTH command can trigger
179 * pre-authentication.
180 */
rsn_preauth_init(struct wpa_sm * sm,const u8 * dst,struct eap_peer_config * eap_conf)181 int rsn_preauth_init(struct wpa_sm *sm, const u8 *dst,
182 struct eap_peer_config *eap_conf)
183 {
184 struct eapol_config eapol_conf;
185 struct eapol_ctx *ctx;
186 int ret;
187
188 if (sm->preauth_eapol)
189 return -1;
190
191 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG,
192 "RSN: starting pre-authentication with " MACSTR, MAC2STR(dst));
193
194 sm->l2_preauth = l2_packet_init(sm->ifname, sm->own_addr,
195 ETH_P_RSN_PREAUTH,
196 rsn_preauth_receive, sm, 0);
197 if (sm->l2_preauth == NULL) {
198 wpa_printf(MSG_WARNING, "RSN: Failed to initialize L2 packet "
199 "processing for pre-authentication");
200 return -2;
201 }
202
203 if (sm->bridge_ifname) {
204 sm->l2_preauth_br = l2_packet_init(sm->bridge_ifname,
205 sm->own_addr,
206 ETH_P_RSN_PREAUTH,
207 rsn_preauth_receive, sm, 0);
208 if (sm->l2_preauth_br == NULL) {
209 wpa_printf(MSG_WARNING, "RSN: Failed to initialize L2 "
210 "packet processing (bridge) for "
211 "pre-authentication");
212 ret = -2;
213 goto fail;
214 }
215 }
216
217 ctx = os_zalloc(sizeof(*ctx));
218 if (ctx == NULL) {
219 wpa_printf(MSG_WARNING, "Failed to allocate EAPOL context.");
220 ret = -4;
221 goto fail;
222 }
223 ctx->ctx = sm->ctx->ctx;
224 ctx->msg_ctx = sm->ctx->ctx;
225 ctx->preauth = 1;
226 ctx->cb = rsn_preauth_eapol_cb;
227 ctx->cb_ctx = sm;
228 ctx->scard_ctx = sm->scard_ctx;
229 ctx->eapol_send = rsn_preauth_eapol_send;
230 ctx->eapol_send_ctx = sm;
231 ctx->set_config_blob = sm->ctx->set_config_blob;
232 ctx->get_config_blob = sm->ctx->get_config_blob;
233
234 sm->preauth_eapol = eapol_sm_init(ctx);
235 if (sm->preauth_eapol == NULL) {
236 os_free(ctx);
237 wpa_printf(MSG_WARNING, "RSN: Failed to initialize EAPOL "
238 "state machines for pre-authentication");
239 ret = -3;
240 goto fail;
241 }
242 os_memset(&eapol_conf, 0, sizeof(eapol_conf));
243 eapol_conf.accept_802_1x_keys = 0;
244 eapol_conf.required_keys = 0;
245 eapol_conf.fast_reauth = sm->fast_reauth;
246 eapol_conf.workaround = sm->eap_workaround;
247 eapol_sm_notify_config(sm->preauth_eapol, eap_conf, &eapol_conf);
248 /*
249 * Use a shorter startPeriod with preauthentication since the first
250 * preauth EAPOL-Start frame may end up being dropped due to race
251 * condition in the AP between the data receive and key configuration
252 * after the 4-Way Handshake.
253 */
254 eapol_sm_configure(sm->preauth_eapol, -1, -1, 5, 6);
255 os_memcpy(sm->preauth_bssid, dst, ETH_ALEN);
256
257 eapol_sm_notify_portValid(sm->preauth_eapol, true);
258 /* 802.1X::portControl = Auto */
259 eapol_sm_notify_portEnabled(sm->preauth_eapol, true);
260
261 eloop_register_timeout(sm->dot11RSNAConfigSATimeout, 0,
262 rsn_preauth_timeout, sm, NULL);
263
264 return 0;
265
266 fail:
267 if (sm->l2_preauth_br) {
268 l2_packet_deinit(sm->l2_preauth_br);
269 sm->l2_preauth_br = NULL;
270 }
271 l2_packet_deinit(sm->l2_preauth);
272 sm->l2_preauth = NULL;
273 return ret;
274 }
275
276
277 /**
278 * rsn_preauth_deinit - Abort RSN pre-authentication
279 * @sm: Pointer to WPA state machine data from wpa_sm_init()
280 *
281 * This function aborts the current RSN pre-authentication (if one is started)
282 * and frees resources allocated for it.
283 */
rsn_preauth_deinit(struct wpa_sm * sm)284 void rsn_preauth_deinit(struct wpa_sm *sm)
285 {
286 if (sm == NULL || !sm->preauth_eapol)
287 return;
288
289 eloop_cancel_timeout(rsn_preauth_timeout, sm, NULL);
290 eapol_sm_deinit(sm->preauth_eapol);
291 sm->preauth_eapol = NULL;
292 os_memset(sm->preauth_bssid, 0, ETH_ALEN);
293
294 l2_packet_deinit(sm->l2_preauth);
295 sm->l2_preauth = NULL;
296 if (sm->l2_preauth_br) {
297 l2_packet_deinit(sm->l2_preauth_br);
298 sm->l2_preauth_br = NULL;
299 }
300 }
301
302
303 /**
304 * rsn_preauth_candidate_process - Process PMKSA candidates
305 * @sm: Pointer to WPA state machine data from wpa_sm_init()
306 *
307 * Go through the PMKSA candidates and start pre-authentication if a candidate
308 * without an existing PMKSA cache entry is found. Processed candidates will be
309 * removed from the list.
310 */
rsn_preauth_candidate_process(struct wpa_sm * sm)311 void rsn_preauth_candidate_process(struct wpa_sm *sm)
312 {
313 struct rsn_pmksa_candidate *candidate, *n;
314
315 if (dl_list_empty(&sm->pmksa_candidates))
316 return;
317
318 /* TODO: drop priority for old candidate entries */
319
320 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: processing PMKSA candidate "
321 "list");
322 if (sm->preauth_eapol ||
323 sm->proto != WPA_PROTO_RSN ||
324 wpa_sm_get_state(sm) != WPA_COMPLETED ||
325 !rsn_preauth_key_mgmt(sm->key_mgmt)) {
326 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: not in suitable "
327 "state for new pre-authentication");
328 return; /* invalid state for new pre-auth */
329 }
330
331 dl_list_for_each_safe(candidate, n, &sm->pmksa_candidates,
332 struct rsn_pmksa_candidate, list) {
333 struct rsn_pmksa_cache_entry *p = NULL;
334 p = pmksa_cache_get(sm->pmksa, candidate->bssid, sm->own_addr,
335 NULL, NULL, 0);
336 if (!ether_addr_equal(sm->bssid, candidate->bssid) &&
337 (p == NULL || p->opportunistic)) {
338 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: PMKSA "
339 "candidate " MACSTR
340 " selected for pre-authentication",
341 MAC2STR(candidate->bssid));
342 dl_list_del(&candidate->list);
343 rsn_preauth_init(sm, candidate->bssid,
344 sm->eap_conf_ctx);
345 os_free(candidate);
346 return;
347 }
348 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: PMKSA candidate "
349 MACSTR " does not need pre-authentication anymore",
350 MAC2STR(candidate->bssid));
351 /* Some drivers (e.g., NDIS) expect to get notified about the
352 * PMKIDs again, so report the existing data now. */
353 if (p) {
354 wpa_sm_add_pmkid(sm, NULL, candidate->bssid, p->pmkid,
355 NULL, p->pmk, p->pmk_len, 0, 0,
356 p->akmp);
357 }
358
359 dl_list_del(&candidate->list);
360 os_free(candidate);
361 }
362 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: no more pending PMKSA "
363 "candidates");
364 }
365
366
367 /**
368 * pmksa_candidate_add - Add a new PMKSA candidate
369 * @sm: Pointer to WPA state machine data from wpa_sm_init()
370 * @bssid: BSSID (authenticator address) of the candidate
371 * @prio: Priority (the smaller number, the higher priority)
372 * @preauth: Whether the candidate AP advertises support for pre-authentication
373 *
374 * This function is used to add PMKSA candidates for RSN pre-authentication. It
375 * is called from scan result processing and from driver events for PMKSA
376 * candidates, i.e., EVENT_PMKID_CANDIDATE events to wpa_supplicant_event().
377 */
pmksa_candidate_add(struct wpa_sm * sm,const u8 * bssid,int prio,int preauth)378 void pmksa_candidate_add(struct wpa_sm *sm, const u8 *bssid,
379 int prio, int preauth)
380 {
381 struct rsn_pmksa_candidate *cand, *pos;
382
383 if (sm->network_ctx && sm->proactive_key_caching)
384 pmksa_cache_get_opportunistic(sm->pmksa, sm->network_ctx,
385 bssid, 0);
386
387 if (!preauth) {
388 wpa_printf(MSG_DEBUG, "RSN: Ignored PMKID candidate without "
389 "preauth flag");
390 return;
391 }
392
393 /* If BSSID already on candidate list, update the priority of the old
394 * entry. Do not override priority based on normal scan results. */
395 cand = NULL;
396 dl_list_for_each(pos, &sm->pmksa_candidates,
397 struct rsn_pmksa_candidate, list) {
398 if (ether_addr_equal(pos->bssid, bssid)) {
399 cand = pos;
400 break;
401 }
402 }
403
404 if (cand) {
405 dl_list_del(&cand->list);
406 if (prio < PMKID_CANDIDATE_PRIO_SCAN)
407 cand->priority = prio;
408 } else {
409 cand = os_zalloc(sizeof(*cand));
410 if (cand == NULL)
411 return;
412 os_memcpy(cand->bssid, bssid, ETH_ALEN);
413 cand->priority = prio;
414 }
415
416 /* Add candidate to the list; order by increasing priority value. i.e.,
417 * highest priority (smallest value) first. */
418 dl_list_for_each(pos, &sm->pmksa_candidates,
419 struct rsn_pmksa_candidate, list) {
420 if (cand->priority <= pos->priority) {
421 if (!pos->list.prev) {
422 /*
423 * This cannot really happen in pracrice since
424 * pos was fetched from the list and the prev
425 * pointer must be set. It looks like clang
426 * static analyzer gets confused with the
427 * dl_list_del(&cand->list) call above and ends
428 * up assuming pos->list.prev could be NULL.
429 */
430 os_free(cand);
431 return;
432 }
433 dl_list_add(pos->list.prev, &cand->list);
434 cand = NULL;
435 break;
436 }
437 }
438 if (cand)
439 dl_list_add_tail(&sm->pmksa_candidates, &cand->list);
440
441 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: added PMKSA cache "
442 "candidate " MACSTR " prio %d", MAC2STR(bssid), prio);
443 rsn_preauth_candidate_process(sm);
444 }
445
446
447 /* TODO: schedule periodic scans if current AP supports preauth */
448
449 /**
450 * rsn_preauth_scan_results - Start processing scan results for canditates
451 * @sm: Pointer to WPA state machine data from wpa_sm_init()
452 * Returns: 0 if ready to process results or -1 to skip processing
453 *
454 * This functions is used to notify RSN code about start of new scan results
455 * processing. The actual scan results will be provided by calling
456 * rsn_preauth_scan_result() for each BSS if this function returned 0.
457 */
rsn_preauth_scan_results(struct wpa_sm * sm)458 int rsn_preauth_scan_results(struct wpa_sm *sm)
459 {
460 if (sm->ssid_len == 0)
461 return -1;
462
463 /*
464 * TODO: is it ok to free all candidates? What about the entries
465 * received from EVENT_PMKID_CANDIDATE?
466 */
467 pmksa_candidate_free(sm);
468
469 return 0;
470 }
471
472
473 /**
474 * rsn_preauth_scan_result - Processing scan result for PMKSA canditates
475 * @sm: Pointer to WPA state machine data from wpa_sm_init()
476 *
477 * Add all suitable APs (Authenticators) from scan results into PMKSA
478 * candidate list.
479 */
rsn_preauth_scan_result(struct wpa_sm * sm,const u8 * bssid,const u8 * ssid,const u8 * rsn)480 void rsn_preauth_scan_result(struct wpa_sm *sm, const u8 *bssid,
481 const u8 *ssid, const u8 *rsn)
482 {
483 struct wpa_ie_data ie;
484 struct rsn_pmksa_cache_entry *pmksa;
485
486 if (ssid[1] != sm->ssid_len ||
487 os_memcmp(ssid + 2, sm->ssid, sm->ssid_len) != 0)
488 return; /* Not for the current SSID */
489
490 if (ether_addr_equal(bssid, sm->bssid))
491 return; /* Ignore current AP */
492
493 if (wpa_parse_wpa_ie(rsn, 2 + rsn[1], &ie))
494 return;
495
496 pmksa = pmksa_cache_get(sm->pmksa, bssid, sm->own_addr, NULL, NULL, 0);
497 if (pmksa && (!pmksa->opportunistic ||
498 !(ie.capabilities & WPA_CAPABILITY_PREAUTH)))
499 return;
500
501 if (!rsn_preauth_key_mgmt(ie.key_mgmt))
502 return;
503
504 /* Give less priority to candidates found from normal scan results. */
505 pmksa_candidate_add(sm, bssid, PMKID_CANDIDATE_PRIO_SCAN,
506 ie.capabilities & WPA_CAPABILITY_PREAUTH);
507 }
508
509
510 #ifdef CONFIG_CTRL_IFACE
511 /**
512 * rsn_preauth_get_status - Get pre-authentication status
513 * @sm: Pointer to WPA state machine data from wpa_sm_init()
514 * @buf: Buffer for status information
515 * @buflen: Maximum buffer length
516 * @verbose: Whether to include verbose status information
517 * Returns: Number of bytes written to buf.
518 *
519 * Query WPA2 pre-authentication for status information. This function fills in
520 * a text area with current status information. If the buffer (buf) is not
521 * large enough, status information will be truncated to fit the buffer.
522 */
rsn_preauth_get_status(struct wpa_sm * sm,char * buf,size_t buflen,int verbose)523 int rsn_preauth_get_status(struct wpa_sm *sm, char *buf, size_t buflen,
524 int verbose)
525 {
526 char *pos = buf, *end = buf + buflen;
527 int res, ret;
528
529 if (sm->preauth_eapol) {
530 ret = os_snprintf(pos, end - pos, "Pre-authentication "
531 "EAPOL state machines:\n");
532 if (os_snprintf_error(end - pos, ret))
533 return pos - buf;
534 pos += ret;
535 res = eapol_sm_get_status(sm->preauth_eapol,
536 pos, end - pos, verbose);
537 if (res >= 0)
538 pos += res;
539 }
540
541 return pos - buf;
542 }
543 #endif /* CONFIG_CTRL_IFACE */
544
545
546 /**
547 * rsn_preauth_in_progress - Verify whether pre-authentication is in progress
548 * @sm: Pointer to WPA state machine data from wpa_sm_init()
549 */
rsn_preauth_in_progress(struct wpa_sm * sm)550 int rsn_preauth_in_progress(struct wpa_sm *sm)
551 {
552 return sm->preauth_eapol != NULL;
553 }
554
555 #endif /* IEEE8021X_EAPOL && !CONFIG_NO_WPA */
556