Line data Source code
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 : #ifdef IEEE8021X_EAPOL
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 : */
37 831 : void pmksa_candidate_free(struct wpa_sm *sm)
38 : {
39 : struct rsn_pmksa_candidate *entry, *n;
40 :
41 831 : if (sm == NULL)
42 856 : return;
43 :
44 806 : dl_list_for_each_safe(entry, n, &sm->pmksa_candidates,
45 : struct rsn_pmksa_candidate, list) {
46 0 : dl_list_del(&entry->list);
47 0 : os_free(entry);
48 : }
49 : }
50 :
51 :
52 16 : static void rsn_preauth_receive(void *ctx, const u8 *src_addr,
53 : const u8 *buf, size_t len)
54 : {
55 16 : struct wpa_sm *sm = ctx;
56 :
57 16 : wpa_printf(MSG_DEBUG, "RX pre-auth from " MACSTR, MAC2STR(src_addr));
58 16 : wpa_hexdump(MSG_MSGDUMP, "RX pre-auth", buf, len);
59 :
60 32 : if (sm->preauth_eapol == NULL ||
61 32 : is_zero_ether_addr(sm->preauth_bssid) ||
62 16 : os_memcmp(sm->preauth_bssid, src_addr, ETH_ALEN) != 0) {
63 0 : wpa_printf(MSG_WARNING, "RSN pre-auth frame received from "
64 : "unexpected source " MACSTR " - dropped",
65 0 : MAC2STR(src_addr));
66 16 : return;
67 : }
68 :
69 16 : eapol_sm_rx_eapol(sm->preauth_eapol, src_addr, buf, len);
70 : }
71 :
72 :
73 4 : static void rsn_preauth_eapol_cb(struct eapol_sm *eapol,
74 : enum eapol_supp_result result,
75 : void *ctx)
76 : {
77 4 : struct wpa_sm *sm = ctx;
78 : u8 pmk[PMK_LEN];
79 :
80 4 : if (result == EAPOL_SUPP_RESULT_SUCCESS) {
81 : int res, pmk_len;
82 4 : pmk_len = PMK_LEN;
83 4 : res = eapol_sm_get_key(eapol, pmk, PMK_LEN);
84 4 : if (res) {
85 : /*
86 : * EAP-LEAP is an exception from other EAP methods: it
87 : * uses only 16-byte PMK.
88 : */
89 0 : res = eapol_sm_get_key(eapol, pmk, 16);
90 0 : pmk_len = 16;
91 : }
92 4 : if (res == 0) {
93 4 : wpa_hexdump_key(MSG_DEBUG, "RSN: PMK from pre-auth",
94 : pmk, pmk_len);
95 4 : sm->pmk_len = pmk_len;
96 8 : pmksa_cache_add(sm->pmksa, pmk, pmk_len,
97 : NULL, 0,
98 4 : sm->preauth_bssid, sm->own_addr,
99 : sm->network_ctx,
100 : WPA_KEY_MGMT_IEEE8021X);
101 : } else {
102 0 : wpa_msg(sm->ctx->msg_ctx, MSG_INFO,
103 : "RSN: failed to get master session key from "
104 : "pre-auth EAPOL state machines");
105 0 : result = EAPOL_SUPP_RESULT_FAILURE;
106 : }
107 : }
108 :
109 28 : wpa_msg(sm->ctx->msg_ctx, MSG_INFO, "RSN: pre-authentication with "
110 24 : MACSTR " %s", MAC2STR(sm->preauth_bssid),
111 : result == EAPOL_SUPP_RESULT_SUCCESS ? "completed successfully" :
112 : "failed");
113 :
114 4 : rsn_preauth_deinit(sm);
115 4 : rsn_preauth_candidate_process(sm);
116 4 : }
117 :
118 :
119 1 : static void rsn_preauth_timeout(void *eloop_ctx, void *timeout_ctx)
120 : {
121 1 : struct wpa_sm *sm = eloop_ctx;
122 :
123 6 : wpa_msg(sm->ctx->msg_ctx, MSG_INFO, "RSN: pre-authentication with "
124 6 : MACSTR " timed out", MAC2STR(sm->preauth_bssid));
125 1 : rsn_preauth_deinit(sm);
126 1 : rsn_preauth_candidate_process(sm);
127 1 : }
128 :
129 :
130 18 : static int rsn_preauth_eapol_send(void *ctx, int type, const u8 *buf,
131 : size_t len)
132 : {
133 18 : struct wpa_sm *sm = ctx;
134 : u8 *msg;
135 : size_t msglen;
136 : int res;
137 :
138 : /* TODO: could add l2_packet_sendmsg that allows fragments to avoid
139 : * extra copy here */
140 :
141 18 : if (sm->l2_preauth == NULL)
142 0 : return -1;
143 :
144 18 : msg = wpa_sm_alloc_eapol(sm, type, buf, len, &msglen, NULL);
145 18 : if (msg == NULL)
146 0 : return -1;
147 :
148 18 : wpa_hexdump(MSG_MSGDUMP, "TX EAPOL (preauth)", msg, msglen);
149 18 : res = l2_packet_send(sm->l2_preauth, sm->preauth_bssid,
150 : ETH_P_RSN_PREAUTH, msg, msglen);
151 18 : os_free(msg);
152 18 : return res;
153 : }
154 :
155 :
156 : /**
157 : * rsn_preauth_init - Start new RSN pre-authentication
158 : * @sm: Pointer to WPA state machine data from wpa_sm_init()
159 : * @dst: Authenticator address (BSSID) with which to preauthenticate
160 : * @eap_conf: Current EAP configuration
161 : * Returns: 0 on success, -1 on another pre-authentication is in progress,
162 : * -2 on layer 2 packet initialization failure, -3 on EAPOL state machine
163 : * initialization failure, -4 on memory allocation failure
164 : *
165 : * This function request an RSN pre-authentication with a given destination
166 : * address. This is usually called for PMKSA candidates found from scan results
167 : * or from driver reports. In addition, ctrl_iface PREAUTH command can trigger
168 : * pre-authentication.
169 : */
170 18 : int rsn_preauth_init(struct wpa_sm *sm, const u8 *dst,
171 : struct eap_peer_config *eap_conf)
172 : {
173 : struct eapol_config eapol_conf;
174 : struct eapol_ctx *ctx;
175 : int ret;
176 :
177 18 : if (sm->preauth_eapol)
178 0 : return -1;
179 :
180 108 : wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG,
181 108 : "RSN: starting pre-authentication with " MACSTR, MAC2STR(dst));
182 :
183 18 : sm->l2_preauth = l2_packet_init(sm->ifname, sm->own_addr,
184 : ETH_P_RSN_PREAUTH,
185 : rsn_preauth_receive, sm, 0);
186 18 : if (sm->l2_preauth == NULL) {
187 1 : wpa_printf(MSG_WARNING, "RSN: Failed to initialize L2 packet "
188 : "processing for pre-authentication");
189 1 : return -2;
190 : }
191 :
192 17 : if (sm->bridge_ifname) {
193 0 : sm->l2_preauth_br = l2_packet_init(sm->bridge_ifname,
194 0 : sm->own_addr,
195 : ETH_P_RSN_PREAUTH,
196 : rsn_preauth_receive, sm, 0);
197 0 : if (sm->l2_preauth_br == NULL) {
198 0 : wpa_printf(MSG_WARNING, "RSN: Failed to initialize L2 "
199 : "packet processing (bridge) for "
200 : "pre-authentication");
201 0 : ret = -2;
202 0 : goto fail;
203 : }
204 : }
205 :
206 17 : ctx = os_zalloc(sizeof(*ctx));
207 17 : if (ctx == NULL) {
208 1 : wpa_printf(MSG_WARNING, "Failed to allocate EAPOL context.");
209 1 : ret = -4;
210 1 : goto fail;
211 : }
212 16 : ctx->ctx = sm->ctx->ctx;
213 16 : ctx->msg_ctx = sm->ctx->ctx;
214 16 : ctx->preauth = 1;
215 16 : ctx->cb = rsn_preauth_eapol_cb;
216 16 : ctx->cb_ctx = sm;
217 16 : ctx->scard_ctx = sm->scard_ctx;
218 16 : ctx->eapol_send = rsn_preauth_eapol_send;
219 16 : ctx->eapol_send_ctx = sm;
220 16 : ctx->set_config_blob = sm->ctx->set_config_blob;
221 16 : ctx->get_config_blob = sm->ctx->get_config_blob;
222 :
223 16 : sm->preauth_eapol = eapol_sm_init(ctx);
224 16 : if (sm->preauth_eapol == NULL) {
225 4 : os_free(ctx);
226 4 : wpa_printf(MSG_WARNING, "RSN: Failed to initialize EAPOL "
227 : "state machines for pre-authentication");
228 4 : ret = -3;
229 4 : goto fail;
230 : }
231 12 : os_memset(&eapol_conf, 0, sizeof(eapol_conf));
232 12 : eapol_conf.accept_802_1x_keys = 0;
233 12 : eapol_conf.required_keys = 0;
234 12 : eapol_conf.fast_reauth = sm->fast_reauth;
235 12 : eapol_conf.workaround = sm->eap_workaround;
236 12 : eapol_sm_notify_config(sm->preauth_eapol, eap_conf, &eapol_conf);
237 : /*
238 : * Use a shorter startPeriod with preauthentication since the first
239 : * preauth EAPOL-Start frame may end up being dropped due to race
240 : * condition in the AP between the data receive and key configuration
241 : * after the 4-Way Handshake.
242 : */
243 12 : eapol_sm_configure(sm->preauth_eapol, -1, -1, 5, 6);
244 12 : os_memcpy(sm->preauth_bssid, dst, ETH_ALEN);
245 :
246 12 : eapol_sm_notify_portValid(sm->preauth_eapol, TRUE);
247 : /* 802.1X::portControl = Auto */
248 12 : eapol_sm_notify_portEnabled(sm->preauth_eapol, TRUE);
249 :
250 12 : eloop_register_timeout(sm->dot11RSNAConfigSATimeout, 0,
251 : rsn_preauth_timeout, sm, NULL);
252 :
253 12 : return 0;
254 :
255 : fail:
256 5 : if (sm->l2_preauth_br) {
257 0 : l2_packet_deinit(sm->l2_preauth_br);
258 0 : sm->l2_preauth_br = NULL;
259 : }
260 5 : l2_packet_deinit(sm->l2_preauth);
261 5 : sm->l2_preauth = NULL;
262 5 : return ret;
263 : }
264 :
265 :
266 : /**
267 : * rsn_preauth_deinit - Abort RSN pre-authentication
268 : * @sm: Pointer to WPA state machine data from wpa_sm_init()
269 : *
270 : * This function aborts the current RSN pre-authentication (if one is started)
271 : * and frees resources allocated for it.
272 : */
273 8945 : void rsn_preauth_deinit(struct wpa_sm *sm)
274 : {
275 8945 : if (sm == NULL || !sm->preauth_eapol)
276 17878 : return;
277 :
278 12 : eloop_cancel_timeout(rsn_preauth_timeout, sm, NULL);
279 12 : eapol_sm_deinit(sm->preauth_eapol);
280 12 : sm->preauth_eapol = NULL;
281 12 : os_memset(sm->preauth_bssid, 0, ETH_ALEN);
282 :
283 12 : l2_packet_deinit(sm->l2_preauth);
284 12 : sm->l2_preauth = NULL;
285 12 : if (sm->l2_preauth_br) {
286 0 : l2_packet_deinit(sm->l2_preauth_br);
287 0 : sm->l2_preauth_br = NULL;
288 : }
289 : }
290 :
291 :
292 : /**
293 : * rsn_preauth_candidate_process - Process PMKSA candidates
294 : * @sm: Pointer to WPA state machine data from wpa_sm_init()
295 : *
296 : * Go through the PMKSA candidates and start pre-authentication if a candidate
297 : * without an existing PMKSA cache entry is found. Processed candidates will be
298 : * removed from the list.
299 : */
300 391 : void rsn_preauth_candidate_process(struct wpa_sm *sm)
301 : {
302 : struct rsn_pmksa_candidate *candidate, *n;
303 :
304 391 : if (dl_list_empty(&sm->pmksa_candidates))
305 388 : return;
306 :
307 : /* TODO: drop priority for old candidate entries */
308 :
309 3 : wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: processing PMKSA candidate "
310 : "list");
311 6 : if (sm->preauth_eapol ||
312 6 : sm->proto != WPA_PROTO_RSN ||
313 6 : wpa_sm_get_state(sm) != WPA_COMPLETED ||
314 3 : (sm->key_mgmt != WPA_KEY_MGMT_IEEE8021X &&
315 0 : sm->key_mgmt != WPA_KEY_MGMT_IEEE8021X_SHA256 &&
316 0 : sm->key_mgmt != WPA_KEY_MGMT_IEEE8021X_SUITE_B &&
317 0 : sm->key_mgmt != WPA_KEY_MGMT_IEEE8021X_SUITE_B_192)) {
318 0 : wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: not in suitable "
319 : "state for new pre-authentication");
320 0 : return; /* invalid state for new pre-auth */
321 : }
322 :
323 3 : dl_list_for_each_safe(candidate, n, &sm->pmksa_candidates,
324 : struct rsn_pmksa_candidate, list) {
325 3 : struct rsn_pmksa_cache_entry *p = NULL;
326 3 : p = pmksa_cache_get(sm->pmksa, candidate->bssid, NULL, NULL);
327 3 : if (os_memcmp(sm->bssid, candidate->bssid, ETH_ALEN) != 0 &&
328 0 : (p == NULL || p->opportunistic)) {
329 18 : wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: PMKSA "
330 : "candidate " MACSTR
331 : " selected for pre-authentication",
332 18 : MAC2STR(candidate->bssid));
333 3 : dl_list_del(&candidate->list);
334 3 : rsn_preauth_init(sm, candidate->bssid,
335 3 : sm->eap_conf_ctx);
336 3 : os_free(candidate);
337 3 : return;
338 : }
339 0 : wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: PMKSA candidate "
340 : MACSTR " does not need pre-authentication anymore",
341 0 : MAC2STR(candidate->bssid));
342 : /* Some drivers (e.g., NDIS) expect to get notified about the
343 : * PMKIDs again, so report the existing data now. */
344 0 : if (p) {
345 0 : wpa_sm_add_pmkid(sm, candidate->bssid, p->pmkid);
346 : }
347 :
348 0 : dl_list_del(&candidate->list);
349 0 : os_free(candidate);
350 : }
351 0 : wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: no more pending PMKSA "
352 : "candidates");
353 : }
354 :
355 :
356 : /**
357 : * pmksa_candidate_add - Add a new PMKSA candidate
358 : * @sm: Pointer to WPA state machine data from wpa_sm_init()
359 : * @bssid: BSSID (authenticator address) of the candidate
360 : * @prio: Priority (the smaller number, the higher priority)
361 : * @preauth: Whether the candidate AP advertises support for pre-authentication
362 : *
363 : * This function is used to add PMKSA candidates for RSN pre-authentication. It
364 : * is called from scan result processing and from driver events for PMKSA
365 : * candidates, i.e., EVENT_PMKID_CANDIDATE events to wpa_supplicant_event().
366 : */
367 17 : void pmksa_candidate_add(struct wpa_sm *sm, const u8 *bssid,
368 : int prio, int preauth)
369 : {
370 : struct rsn_pmksa_candidate *cand, *pos;
371 :
372 17 : if (sm->network_ctx && sm->proactive_key_caching)
373 2 : pmksa_cache_get_opportunistic(sm->pmksa, sm->network_ctx,
374 : bssid);
375 :
376 17 : if (!preauth) {
377 14 : wpa_printf(MSG_DEBUG, "RSN: Ignored PMKID candidate without "
378 : "preauth flag");
379 14 : return;
380 : }
381 :
382 : /* If BSSID already on candidate list, update the priority of the old
383 : * entry. Do not override priority based on normal scan results. */
384 3 : cand = NULL;
385 3 : dl_list_for_each(pos, &sm->pmksa_candidates,
386 : struct rsn_pmksa_candidate, list) {
387 0 : if (os_memcmp(pos->bssid, bssid, ETH_ALEN) == 0) {
388 0 : cand = pos;
389 0 : break;
390 : }
391 : }
392 :
393 3 : if (cand) {
394 0 : dl_list_del(&cand->list);
395 0 : if (prio < PMKID_CANDIDATE_PRIO_SCAN)
396 0 : cand->priority = prio;
397 : } else {
398 3 : cand = os_zalloc(sizeof(*cand));
399 3 : if (cand == NULL)
400 0 : return;
401 3 : os_memcpy(cand->bssid, bssid, ETH_ALEN);
402 3 : cand->priority = prio;
403 : }
404 :
405 : /* Add candidate to the list; order by increasing priority value. i.e.,
406 : * highest priority (smallest value) first. */
407 3 : dl_list_for_each(pos, &sm->pmksa_candidates,
408 : struct rsn_pmksa_candidate, list) {
409 0 : if (cand->priority <= pos->priority) {
410 0 : if (!pos->list.prev) {
411 : /*
412 : * This cannot really happen in pracrice since
413 : * pos was fetched from the list and the prev
414 : * pointer must be set. It looks like clang
415 : * static analyzer gets confused with the
416 : * dl_list_del(&cand->list) call above and ends
417 : * up assuming pos->list.prev could be NULL.
418 : */
419 0 : os_free(cand);
420 0 : return;
421 : }
422 0 : dl_list_add(pos->list.prev, &cand->list);
423 0 : cand = NULL;
424 0 : break;
425 : }
426 : }
427 3 : if (cand)
428 3 : dl_list_add_tail(&sm->pmksa_candidates, &cand->list);
429 :
430 18 : wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: added PMKSA cache "
431 18 : "candidate " MACSTR " prio %d", MAC2STR(bssid), prio);
432 3 : rsn_preauth_candidate_process(sm);
433 : }
434 :
435 :
436 : /* TODO: schedule periodic scans if current AP supports preauth */
437 :
438 : /**
439 : * rsn_preauth_scan_results - Start processing scan results for canditates
440 : * @sm: Pointer to WPA state machine data from wpa_sm_init()
441 : * Returns: 0 if ready to process results or -1 to skip processing
442 : *
443 : * This functions is used to notify RSN code about start of new scan results
444 : * processing. The actual scan results will be provided by calling
445 : * rsn_preauth_scan_result() for each BSS if this function returned 0.
446 : */
447 1554 : int rsn_preauth_scan_results(struct wpa_sm *sm)
448 : {
449 1554 : if (sm->ssid_len == 0)
450 1335 : return -1;
451 :
452 : /*
453 : * TODO: is it ok to free all candidates? What about the entries
454 : * received from EVENT_PMKID_CANDIDATE?
455 : */
456 219 : pmksa_candidate_free(sm);
457 :
458 219 : return 0;
459 : }
460 :
461 :
462 : /**
463 : * rsn_preauth_scan_result - Processing scan result for PMKSA canditates
464 : * @sm: Pointer to WPA state machine data from wpa_sm_init()
465 : *
466 : * Add all suitable APs (Authenticators) from scan results into PMKSA
467 : * candidate list.
468 : */
469 187 : void rsn_preauth_scan_result(struct wpa_sm *sm, const u8 *bssid,
470 : const u8 *ssid, const u8 *rsn)
471 : {
472 : struct wpa_ie_data ie;
473 : struct rsn_pmksa_cache_entry *pmksa;
474 :
475 366 : if (ssid[1] != sm->ssid_len ||
476 179 : os_memcmp(ssid + 2, sm->ssid, sm->ssid_len) != 0)
477 182 : return; /* Not for the current SSID */
478 :
479 175 : if (os_memcmp(bssid, sm->bssid, ETH_ALEN) == 0)
480 141 : return; /* Ignore current AP */
481 :
482 34 : if (wpa_parse_wpa_ie(rsn, 2 + rsn[1], &ie))
483 0 : return;
484 :
485 34 : pmksa = pmksa_cache_get(sm->pmksa, bssid, NULL, NULL);
486 34 : if (pmksa && (!pmksa->opportunistic ||
487 0 : !(ie.capabilities & WPA_CAPABILITY_PREAUTH)))
488 17 : return;
489 :
490 : /* Give less priority to candidates found from normal scan results. */
491 17 : pmksa_candidate_add(sm, bssid, PMKID_CANDIDATE_PRIO_SCAN,
492 17 : ie.capabilities & WPA_CAPABILITY_PREAUTH);
493 : }
494 :
495 :
496 : #ifdef CONFIG_CTRL_IFACE
497 : /**
498 : * rsn_preauth_get_status - Get pre-authentication status
499 : * @sm: Pointer to WPA state machine data from wpa_sm_init()
500 : * @buf: Buffer for status information
501 : * @buflen: Maximum buffer length
502 : * @verbose: Whether to include verbose status information
503 : * Returns: Number of bytes written to buf.
504 : *
505 : * Query WPA2 pre-authentication for status information. This function fills in
506 : * a text area with current status information. If the buffer (buf) is not
507 : * large enough, status information will be truncated to fit the buffer.
508 : */
509 3257 : int rsn_preauth_get_status(struct wpa_sm *sm, char *buf, size_t buflen,
510 : int verbose)
511 : {
512 3257 : char *pos = buf, *end = buf + buflen;
513 : int res, ret;
514 :
515 3257 : if (sm->preauth_eapol) {
516 3 : ret = os_snprintf(pos, end - pos, "Pre-authentication "
517 : "EAPOL state machines:\n");
518 3 : if (os_snprintf_error(end - pos, ret))
519 0 : return pos - buf;
520 3 : pos += ret;
521 3 : res = eapol_sm_get_status(sm->preauth_eapol,
522 3 : pos, end - pos, verbose);
523 3 : if (res >= 0)
524 3 : pos += res;
525 : }
526 :
527 3257 : return pos - buf;
528 : }
529 : #endif /* CONFIG_CTRL_IFACE */
530 :
531 :
532 : /**
533 : * rsn_preauth_in_progress - Verify whether pre-authentication is in progress
534 : * @sm: Pointer to WPA state machine data from wpa_sm_init()
535 : */
536 0 : int rsn_preauth_in_progress(struct wpa_sm *sm)
537 : {
538 0 : return sm->preauth_eapol != NULL;
539 : }
540 :
541 : #endif /* IEEE8021X_EAPOL */
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