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 */
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_receive(void * ctx,const u8 * src_addr,const u8 * buf,size_t len)52 static void rsn_preauth_receive(void *ctx, const u8 *src_addr,
53 const u8 *buf, size_t len)
54 {
55 struct wpa_sm *sm = ctx;
56
57 wpa_printf(MSG_DEBUG, "RX pre-auth from " MACSTR, MAC2STR(src_addr));
58 wpa_hexdump(MSG_MSGDUMP, "RX pre-auth", buf, len);
59
60 if (sm->preauth_eapol == NULL ||
61 is_zero_ether_addr(sm->preauth_bssid) ||
62 os_memcmp(sm->preauth_bssid, src_addr, ETH_ALEN) != 0) {
63 wpa_printf(MSG_WARNING, "RSN pre-auth frame received from "
64 "unexpected source " MACSTR " - dropped",
65 MAC2STR(src_addr));
66 return;
67 }
68
69 eapol_sm_rx_eapol(sm->preauth_eapol, src_addr, buf, len);
70 }
71
72
rsn_preauth_eapol_cb(struct eapol_sm * eapol,enum eapol_supp_result result,void * ctx)73 static void rsn_preauth_eapol_cb(struct eapol_sm *eapol,
74 enum eapol_supp_result result,
75 void *ctx)
76 {
77 struct wpa_sm *sm = ctx;
78 u8 pmk[PMK_LEN];
79
80 if (result == EAPOL_SUPP_RESULT_SUCCESS) {
81 int res, pmk_len;
82 pmk_len = PMK_LEN;
83 res = eapol_sm_get_key(eapol, pmk, PMK_LEN);
84 if (res) {
85 /*
86 * EAP-LEAP is an exception from other EAP methods: it
87 * uses only 16-byte PMK.
88 */
89 res = eapol_sm_get_key(eapol, pmk, 16);
90 pmk_len = 16;
91 }
92 if (res == 0) {
93 wpa_hexdump_key(MSG_DEBUG, "RSN: PMK from pre-auth",
94 pmk, pmk_len);
95 sm->pmk_len = pmk_len;
96 pmksa_cache_add(sm->pmksa, pmk, pmk_len,
97 NULL, 0,
98 sm->preauth_bssid, sm->own_addr,
99 sm->network_ctx,
100 WPA_KEY_MGMT_IEEE8021X);
101 } else {
102 wpa_msg(sm->ctx->msg_ctx, MSG_INFO,
103 "RSN: failed to get master session key from "
104 "pre-auth EAPOL state machines");
105 result = EAPOL_SUPP_RESULT_FAILURE;
106 }
107 }
108
109 wpa_msg(sm->ctx->msg_ctx, MSG_INFO, "RSN: pre-authentication with "
110 MACSTR " %s", MAC2STR(sm->preauth_bssid),
111 result == EAPOL_SUPP_RESULT_SUCCESS ? "completed successfully" :
112 "failed");
113
114 rsn_preauth_deinit(sm);
115 rsn_preauth_candidate_process(sm);
116 }
117
118
rsn_preauth_timeout(void * eloop_ctx,void * timeout_ctx)119 static void rsn_preauth_timeout(void *eloop_ctx, void *timeout_ctx)
120 {
121 struct wpa_sm *sm = eloop_ctx;
122
123 wpa_msg(sm->ctx->msg_ctx, MSG_INFO, "RSN: pre-authentication with "
124 MACSTR " timed out", MAC2STR(sm->preauth_bssid));
125 rsn_preauth_deinit(sm);
126 rsn_preauth_candidate_process(sm);
127 }
128
129
rsn_preauth_eapol_send(void * ctx,int type,const u8 * buf,size_t len)130 static int rsn_preauth_eapol_send(void *ctx, int type, const u8 *buf,
131 size_t len)
132 {
133 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 if (sm->l2_preauth == NULL)
142 return -1;
143
144 msg = wpa_sm_alloc_eapol(sm, type, buf, len, &msglen, NULL);
145 if (msg == NULL)
146 return -1;
147
148 wpa_hexdump(MSG_MSGDUMP, "TX EAPOL (preauth)", msg, msglen);
149 res = l2_packet_send(sm->l2_preauth, sm->preauth_bssid,
150 ETH_P_RSN_PREAUTH, msg, msglen);
151 os_free(msg);
152 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 */
rsn_preauth_init(struct wpa_sm * sm,const u8 * dst,struct eap_peer_config * eap_conf)170 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 if (sm->preauth_eapol)
178 return -1;
179
180 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG,
181 "RSN: starting pre-authentication with " MACSTR, MAC2STR(dst));
182
183 sm->l2_preauth = l2_packet_init(sm->ifname, sm->own_addr,
184 ETH_P_RSN_PREAUTH,
185 rsn_preauth_receive, sm, 0);
186 if (sm->l2_preauth == NULL) {
187 wpa_printf(MSG_WARNING, "RSN: Failed to initialize L2 packet "
188 "processing for pre-authentication");
189 return -2;
190 }
191
192 if (sm->bridge_ifname) {
193 sm->l2_preauth_br = l2_packet_init(sm->bridge_ifname,
194 sm->own_addr,
195 ETH_P_RSN_PREAUTH,
196 rsn_preauth_receive, sm, 0);
197 if (sm->l2_preauth_br == NULL) {
198 wpa_printf(MSG_WARNING, "RSN: Failed to initialize L2 "
199 "packet processing (bridge) for "
200 "pre-authentication");
201 ret = -2;
202 goto fail;
203 }
204 }
205
206 ctx = os_zalloc(sizeof(*ctx));
207 if (ctx == NULL) {
208 wpa_printf(MSG_WARNING, "Failed to allocate EAPOL context.");
209 ret = -4;
210 goto fail;
211 }
212 ctx->ctx = sm->ctx->ctx;
213 ctx->msg_ctx = sm->ctx->ctx;
214 ctx->preauth = 1;
215 ctx->cb = rsn_preauth_eapol_cb;
216 ctx->cb_ctx = sm;
217 ctx->scard_ctx = sm->scard_ctx;
218 ctx->eapol_send = rsn_preauth_eapol_send;
219 ctx->eapol_send_ctx = sm;
220 ctx->set_config_blob = sm->ctx->set_config_blob;
221 ctx->get_config_blob = sm->ctx->get_config_blob;
222
223 sm->preauth_eapol = eapol_sm_init(ctx);
224 if (sm->preauth_eapol == NULL) {
225 os_free(ctx);
226 wpa_printf(MSG_WARNING, "RSN: Failed to initialize EAPOL "
227 "state machines for pre-authentication");
228 ret = -3;
229 goto fail;
230 }
231 os_memset(&eapol_conf, 0, sizeof(eapol_conf));
232 eapol_conf.accept_802_1x_keys = 0;
233 eapol_conf.required_keys = 0;
234 eapol_conf.fast_reauth = sm->fast_reauth;
235 eapol_conf.workaround = sm->eap_workaround;
236 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 eapol_sm_configure(sm->preauth_eapol, -1, -1, 5, 6);
244 os_memcpy(sm->preauth_bssid, dst, ETH_ALEN);
245
246 eapol_sm_notify_portValid(sm->preauth_eapol, TRUE);
247 /* 802.1X::portControl = Auto */
248 eapol_sm_notify_portEnabled(sm->preauth_eapol, TRUE);
249
250 eloop_register_timeout(sm->dot11RSNAConfigSATimeout, 0,
251 rsn_preauth_timeout, sm, NULL);
252
253 return 0;
254
255 fail:
256 if (sm->l2_preauth_br) {
257 l2_packet_deinit(sm->l2_preauth_br);
258 sm->l2_preauth_br = NULL;
259 }
260 l2_packet_deinit(sm->l2_preauth);
261 sm->l2_preauth = NULL;
262 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 */
rsn_preauth_deinit(struct wpa_sm * sm)273 void rsn_preauth_deinit(struct wpa_sm *sm)
274 {
275 if (sm == NULL || !sm->preauth_eapol)
276 return;
277
278 eloop_cancel_timeout(rsn_preauth_timeout, sm, NULL);
279 eapol_sm_deinit(sm->preauth_eapol);
280 sm->preauth_eapol = NULL;
281 os_memset(sm->preauth_bssid, 0, ETH_ALEN);
282
283 l2_packet_deinit(sm->l2_preauth);
284 sm->l2_preauth = NULL;
285 if (sm->l2_preauth_br) {
286 l2_packet_deinit(sm->l2_preauth_br);
287 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 */
rsn_preauth_candidate_process(struct wpa_sm * sm)300 void rsn_preauth_candidate_process(struct wpa_sm *sm)
301 {
302 struct rsn_pmksa_candidate *candidate, *n;
303
304 if (dl_list_empty(&sm->pmksa_candidates))
305 return;
306
307 /* TODO: drop priority for old candidate entries */
308
309 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: processing PMKSA candidate "
310 "list");
311 if (sm->preauth_eapol ||
312 sm->proto != WPA_PROTO_RSN ||
313 wpa_sm_get_state(sm) != WPA_COMPLETED ||
314 (sm->key_mgmt != WPA_KEY_MGMT_IEEE8021X &&
315 sm->key_mgmt != WPA_KEY_MGMT_IEEE8021X_SHA256 &&
316 sm->key_mgmt != WPA_KEY_MGMT_IEEE8021X_SUITE_B &&
317 sm->key_mgmt != WPA_KEY_MGMT_IEEE8021X_SUITE_B_192)) {
318 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: not in suitable "
319 "state for new pre-authentication");
320 return; /* invalid state for new pre-auth */
321 }
322
323 dl_list_for_each_safe(candidate, n, &sm->pmksa_candidates,
324 struct rsn_pmksa_candidate, list) {
325 struct rsn_pmksa_cache_entry *p = NULL;
326 p = pmksa_cache_get(sm->pmksa, candidate->bssid, NULL, NULL);
327 if (os_memcmp(sm->bssid, candidate->bssid, ETH_ALEN) != 0 &&
328 (p == NULL || p->opportunistic)) {
329 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: PMKSA "
330 "candidate " MACSTR
331 " selected for pre-authentication",
332 MAC2STR(candidate->bssid));
333 dl_list_del(&candidate->list);
334 rsn_preauth_init(sm, candidate->bssid,
335 sm->eap_conf_ctx);
336 os_free(candidate);
337 return;
338 }
339 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: PMKSA candidate "
340 MACSTR " does not need pre-authentication anymore",
341 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 if (p) {
345 wpa_sm_add_pmkid(sm, candidate->bssid, p->pmkid);
346 }
347
348 dl_list_del(&candidate->list);
349 os_free(candidate);
350 }
351 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 */
pmksa_candidate_add(struct wpa_sm * sm,const u8 * bssid,int prio,int preauth)367 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 if (sm->network_ctx && sm->proactive_key_caching)
373 pmksa_cache_get_opportunistic(sm->pmksa, sm->network_ctx,
374 bssid);
375
376 if (!preauth) {
377 wpa_printf(MSG_DEBUG, "RSN: Ignored PMKID candidate without "
378 "preauth flag");
379 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 cand = NULL;
385 dl_list_for_each(pos, &sm->pmksa_candidates,
386 struct rsn_pmksa_candidate, list) {
387 if (os_memcmp(pos->bssid, bssid, ETH_ALEN) == 0) {
388 cand = pos;
389 break;
390 }
391 }
392
393 if (cand) {
394 dl_list_del(&cand->list);
395 if (prio < PMKID_CANDIDATE_PRIO_SCAN)
396 cand->priority = prio;
397 } else {
398 cand = os_zalloc(sizeof(*cand));
399 if (cand == NULL)
400 return;
401 os_memcpy(cand->bssid, bssid, ETH_ALEN);
402 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 dl_list_for_each(pos, &sm->pmksa_candidates,
408 struct rsn_pmksa_candidate, list) {
409 if (cand->priority <= pos->priority) {
410 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 os_free(cand);
420 return;
421 }
422 dl_list_add(pos->list.prev, &cand->list);
423 cand = NULL;
424 break;
425 }
426 }
427 if (cand)
428 dl_list_add_tail(&sm->pmksa_candidates, &cand->list);
429
430 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: added PMKSA cache "
431 "candidate " MACSTR " prio %d", MAC2STR(bssid), prio);
432 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 */
rsn_preauth_scan_results(struct wpa_sm * sm)447 int rsn_preauth_scan_results(struct wpa_sm *sm)
448 {
449 if (sm->ssid_len == 0)
450 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 pmksa_candidate_free(sm);
457
458 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 */
rsn_preauth_scan_result(struct wpa_sm * sm,const u8 * bssid,const u8 * ssid,const u8 * rsn)469 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 if (ssid[1] != sm->ssid_len ||
476 os_memcmp(ssid + 2, sm->ssid, sm->ssid_len) != 0)
477 return; /* Not for the current SSID */
478
479 if (os_memcmp(bssid, sm->bssid, ETH_ALEN) == 0)
480 return; /* Ignore current AP */
481
482 if (wpa_parse_wpa_ie(rsn, 2 + rsn[1], &ie))
483 return;
484
485 pmksa = pmksa_cache_get(sm->pmksa, bssid, NULL, NULL);
486 if (pmksa && (!pmksa->opportunistic ||
487 !(ie.capabilities & WPA_CAPABILITY_PREAUTH)))
488 return;
489
490 /* Give less priority to candidates found from normal scan results. */
491 pmksa_candidate_add(sm, bssid, PMKID_CANDIDATE_PRIO_SCAN,
492 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 */
rsn_preauth_get_status(struct wpa_sm * sm,char * buf,size_t buflen,int verbose)509 int rsn_preauth_get_status(struct wpa_sm *sm, char *buf, size_t buflen,
510 int verbose)
511 {
512 char *pos = buf, *end = buf + buflen;
513 int res, ret;
514
515 if (sm->preauth_eapol) {
516 ret = os_snprintf(pos, end - pos, "Pre-authentication "
517 "EAPOL state machines:\n");
518 if (os_snprintf_error(end - pos, ret))
519 return pos - buf;
520 pos += ret;
521 res = eapol_sm_get_status(sm->preauth_eapol,
522 pos, end - pos, verbose);
523 if (res >= 0)
524 pos += res;
525 }
526
527 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 */
rsn_preauth_in_progress(struct wpa_sm * sm)536 int rsn_preauth_in_progress(struct wpa_sm *sm)
537 {
538 return sm->preauth_eapol != NULL;
539 }
540
541 #endif /* IEEE8021X_EAPOL */
542