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