1 /*
2 * WPA Supplicant - RSN pre-authentication
3 * Copyright (c) 2003-2006, Jouni Malinen <j@w1.fi>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 *
9 * Alternatively, this software may be distributed under the terms of BSD
10 * license.
11 *
12 * See README and COPYING for more details.
13 */
14
15 #include "includes.h"
16
17 #include "common.h"
18 #include "wpa.h"
19 #include "driver.h"
20 #include "eloop.h"
21 #include "config.h"
22 #include "l2_packet.h"
23 #include "eapol_sm.h"
24 #include "preauth.h"
25 #include "pmksa_cache.h"
26 #include "wpa_i.h"
27
28
29 #define PMKID_CANDIDATE_PRIO_SCAN 1000
30
31
32 struct rsn_pmksa_candidate {
33 struct rsn_pmksa_candidate *next;
34 u8 bssid[ETH_ALEN];
35 int priority;
36 };
37
38
39 /**
40 * pmksa_candidate_free - Free all entries in PMKSA candidate list
41 * @sm: Pointer to WPA state machine data from wpa_sm_init()
42 */
pmksa_candidate_free(struct wpa_sm * sm)43 void pmksa_candidate_free(struct wpa_sm *sm)
44 {
45 struct rsn_pmksa_candidate *entry, *prev;
46
47 if (sm == NULL)
48 return;
49
50 entry = sm->pmksa_candidates;
51 sm->pmksa_candidates = NULL;
52 while (entry) {
53 prev = entry;
54 entry = entry->next;
55 os_free(prev);
56 }
57 }
58
59
60 #if defined(IEEE8021X_EAPOL) && !defined(CONFIG_NO_WPA2)
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 os_memcmp(sm->preauth_bssid, "\x00\x00\x00\x00\x00\x00",
72 ETH_ALEN) == 0 ||
73 os_memcmp(sm->preauth_bssid, src_addr, ETH_ALEN) != 0) {
74 wpa_printf(MSG_WARNING, "RSN pre-auth frame received from "
75 "unexpected source " MACSTR " - dropped",
76 MAC2STR(src_addr));
77 return;
78 }
79
80 eapol_sm_rx_eapol(sm->preauth_eapol, src_addr, buf, len);
81 }
82
83
rsn_preauth_eapol_cb(struct eapol_sm * eapol,int success,void * ctx)84 static void rsn_preauth_eapol_cb(struct eapol_sm *eapol, int success,
85 void *ctx)
86 {
87 struct wpa_sm *sm = ctx;
88 u8 pmk[PMK_LEN];
89
90 if (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,
107 sm->preauth_bssid, sm->own_addr,
108 sm->cur_ssid);
109 } else {
110 wpa_msg(sm->ctx->ctx, MSG_INFO, "RSN: failed to get "
111 "master session key from pre-auth EAPOL state "
112 "machines");
113 success = 0;
114 }
115 }
116
117 wpa_msg(sm->ctx->ctx, MSG_INFO, "RSN: pre-authentication with " MACSTR
118 " %s", MAC2STR(sm->preauth_bssid),
119 success ? "completed successfully" : "failed");
120
121 rsn_preauth_deinit(sm);
122 rsn_preauth_candidate_process(sm);
123 }
124
125
rsn_preauth_timeout(void * eloop_ctx,void * timeout_ctx)126 static void rsn_preauth_timeout(void *eloop_ctx, void *timeout_ctx)
127 {
128 struct wpa_sm *sm = eloop_ctx;
129
130 wpa_msg(sm->ctx->ctx, MSG_INFO, "RSN: pre-authentication with " MACSTR
131 " timed out", MAC2STR(sm->preauth_bssid));
132 rsn_preauth_deinit(sm);
133 rsn_preauth_candidate_process(sm);
134 }
135
136
rsn_preauth_eapol_send(void * ctx,int type,const u8 * buf,size_t len)137 static int rsn_preauth_eapol_send(void *ctx, int type, const u8 *buf,
138 size_t len)
139 {
140 struct wpa_sm *sm = ctx;
141 u8 *msg;
142 size_t msglen;
143 int res;
144
145 /* TODO: could add l2_packet_sendmsg that allows fragments to avoid
146 * extra copy here */
147
148 if (sm->l2_preauth == NULL)
149 return -1;
150
151 msg = wpa_sm_alloc_eapol(sm, type, buf, len, &msglen, NULL);
152 if (msg == NULL)
153 return -1;
154
155 wpa_hexdump(MSG_MSGDUMP, "TX EAPOL (preauth)", msg, msglen);
156 res = l2_packet_send(sm->l2_preauth, sm->preauth_bssid,
157 ETH_P_RSN_PREAUTH, msg, msglen);
158 os_free(msg);
159 return res;
160 }
161
162
163 /**
164 * rsn_preauth_init - Start new RSN pre-authentication
165 * @sm: Pointer to WPA state machine data from wpa_sm_init()
166 * @dst: Authenticator address (BSSID) with which to preauthenticate
167 * @config: Current network configuration
168 * Returns: 0 on success, -1 on another pre-authentication is in progress,
169 * -2 on layer 2 packet initialization failure, -3 on EAPOL state machine
170 * initialization failure, -4 on memory allocation failure
171 *
172 * This function request an RSN pre-authentication with a given destination
173 * address. This is usually called for PMKSA candidates found from scan results
174 * or from driver reports. In addition, ctrl_iface PREAUTH command can trigger
175 * pre-authentication.
176 */
rsn_preauth_init(struct wpa_sm * sm,const u8 * dst,struct wpa_ssid * config)177 int rsn_preauth_init(struct wpa_sm *sm, const u8 *dst, struct wpa_ssid *config)
178 {
179 struct eapol_config eapol_conf;
180 struct eapol_ctx *ctx;
181
182 if (sm->preauth_eapol)
183 return -1;
184
185 wpa_msg(sm->ctx->ctx, MSG_DEBUG, "RSN: starting pre-authentication "
186 "with " MACSTR, MAC2STR(dst));
187
188 sm->l2_preauth = l2_packet_init(sm->ifname, sm->own_addr,
189 ETH_P_RSN_PREAUTH,
190 rsn_preauth_receive, sm, 0);
191 if (sm->l2_preauth == NULL) {
192 wpa_printf(MSG_WARNING, "RSN: Failed to initialize L2 packet "
193 "processing for pre-authentication");
194 return -2;
195 }
196
197 if (sm->bridge_ifname) {
198 sm->l2_preauth_br = l2_packet_init(sm->bridge_ifname,
199 sm->own_addr,
200 ETH_P_RSN_PREAUTH,
201 rsn_preauth_receive, sm, 0);
202 if (sm->l2_preauth_br == NULL) {
203 wpa_printf(MSG_WARNING, "RSN: Failed to initialize L2 "
204 "packet processing (bridge) for "
205 "pre-authentication");
206 return -2;
207 }
208 }
209
210 ctx = os_zalloc(sizeof(*ctx));
211 if (ctx == NULL) {
212 wpa_printf(MSG_WARNING, "Failed to allocate EAPOL context.");
213 return -4;
214 }
215 ctx->ctx = sm->ctx->ctx;
216 ctx->msg_ctx = sm->ctx->ctx;
217 ctx->preauth = 1;
218 ctx->cb = rsn_preauth_eapol_cb;
219 ctx->cb_ctx = sm;
220 ctx->scard_ctx = sm->scard_ctx;
221 ctx->eapol_send = rsn_preauth_eapol_send;
222 ctx->eapol_send_ctx = sm;
223 ctx->set_config_blob = sm->ctx->set_config_blob;
224 ctx->get_config_blob = sm->ctx->get_config_blob;
225
226 sm->preauth_eapol = eapol_sm_init(ctx);
227 if (sm->preauth_eapol == NULL) {
228 os_free(ctx);
229 wpa_printf(MSG_WARNING, "RSN: Failed to initialize EAPOL "
230 "state machines for pre-authentication");
231 return -3;
232 }
233 os_memset(&eapol_conf, 0, sizeof(eapol_conf));
234 eapol_conf.accept_802_1x_keys = 0;
235 eapol_conf.required_keys = 0;
236 eapol_conf.fast_reauth = sm->fast_reauth;
237 if (config)
238 eapol_conf.workaround = config->eap_workaround;
239 eapol_sm_notify_config(sm->preauth_eapol, config, &eapol_conf);
240 /*
241 * Use a shorter startPeriod with preauthentication since the first
242 * preauth EAPOL-Start frame may end up being dropped due to race
243 * condition in the AP between the data receive and key configuration
244 * after the 4-Way Handshake.
245 */
246 eapol_sm_configure(sm->preauth_eapol, -1, -1, 5, 6);
247 os_memcpy(sm->preauth_bssid, dst, ETH_ALEN);
248
249 eapol_sm_notify_portValid(sm->preauth_eapol, TRUE);
250 /* 802.1X::portControl = Auto */
251 eapol_sm_notify_portEnabled(sm->preauth_eapol, TRUE);
252
253 eloop_register_timeout(sm->dot11RSNAConfigSATimeout, 0,
254 rsn_preauth_timeout, sm, NULL);
255
256 return 0;
257 }
258
259
260 /**
261 * rsn_preauth_deinit - Abort RSN pre-authentication
262 * @sm: Pointer to WPA state machine data from wpa_sm_init()
263 *
264 * This function aborts the current RSN pre-authentication (if one is started)
265 * and frees resources allocated for it.
266 */
rsn_preauth_deinit(struct wpa_sm * sm)267 void rsn_preauth_deinit(struct wpa_sm *sm)
268 {
269 if (sm == NULL || !sm->preauth_eapol)
270 return;
271
272 eloop_cancel_timeout(rsn_preauth_timeout, sm, NULL);
273 eapol_sm_deinit(sm->preauth_eapol);
274 sm->preauth_eapol = NULL;
275 os_memset(sm->preauth_bssid, 0, ETH_ALEN);
276
277 l2_packet_deinit(sm->l2_preauth);
278 sm->l2_preauth = NULL;
279 if (sm->l2_preauth_br) {
280 l2_packet_deinit(sm->l2_preauth_br);
281 sm->l2_preauth_br = NULL;
282 }
283 }
284
285
286 /**
287 * rsn_preauth_candidate_process - Process PMKSA candidates
288 * @sm: Pointer to WPA state machine data from wpa_sm_init()
289 *
290 * Go through the PMKSA candidates and start pre-authentication if a candidate
291 * without an existing PMKSA cache entry is found. Processed candidates will be
292 * removed from the list.
293 */
rsn_preauth_candidate_process(struct wpa_sm * sm)294 void rsn_preauth_candidate_process(struct wpa_sm *sm)
295 {
296 struct rsn_pmksa_candidate *candidate;
297
298 if (sm->pmksa_candidates == NULL)
299 return;
300
301 /* TODO: drop priority for old candidate entries */
302
303 wpa_msg(sm->ctx->ctx, MSG_DEBUG, "RSN: processing PMKSA candidate "
304 "list");
305 if (sm->preauth_eapol ||
306 sm->proto != WPA_PROTO_RSN ||
307 wpa_sm_get_state(sm) != WPA_COMPLETED ||
308 sm->key_mgmt != WPA_KEY_MGMT_IEEE8021X) {
309 wpa_msg(sm->ctx->ctx, MSG_DEBUG, "RSN: not in suitable state "
310 "for new pre-authentication");
311 return; /* invalid state for new pre-auth */
312 }
313
314 while (sm->pmksa_candidates) {
315 struct rsn_pmksa_cache_entry *p = NULL;
316 candidate = sm->pmksa_candidates;
317 p = pmksa_cache_get(sm->pmksa, candidate->bssid, NULL);
318 if (os_memcmp(sm->bssid, candidate->bssid, ETH_ALEN) != 0 &&
319 (p == NULL || p->opportunistic)) {
320 wpa_msg(sm->ctx->ctx, MSG_DEBUG, "RSN: PMKSA "
321 "candidate " MACSTR
322 " selected for pre-authentication",
323 MAC2STR(candidate->bssid));
324 sm->pmksa_candidates = candidate->next;
325 rsn_preauth_init(sm, candidate->bssid, sm->cur_ssid);
326 os_free(candidate);
327 return;
328 }
329 wpa_msg(sm->ctx->ctx, MSG_DEBUG, "RSN: PMKSA candidate "
330 MACSTR " does not need pre-authentication anymore",
331 MAC2STR(candidate->bssid));
332 /* Some drivers (e.g., NDIS) expect to get notified about the
333 * PMKIDs again, so report the existing data now. */
334 if (p) {
335 wpa_sm_add_pmkid(sm, candidate->bssid, p->pmkid);
336 }
337
338 sm->pmksa_candidates = candidate->next;
339 os_free(candidate);
340 }
341 wpa_msg(sm->ctx->ctx, MSG_DEBUG, "RSN: no more pending PMKSA "
342 "candidates");
343 }
344
345
346 /**
347 * pmksa_candidate_add - Add a new PMKSA candidate
348 * @sm: Pointer to WPA state machine data from wpa_sm_init()
349 * @bssid: BSSID (authenticator address) of the candidate
350 * @prio: Priority (the smaller number, the higher priority)
351 * @preauth: Whether the candidate AP advertises support for pre-authentication
352 *
353 * This function is used to add PMKSA candidates for RSN pre-authentication. It
354 * is called from scan result processing and from driver events for PMKSA
355 * candidates, i.e., EVENT_PMKID_CANDIDATE events to wpa_supplicant_event().
356 */
pmksa_candidate_add(struct wpa_sm * sm,const u8 * bssid,int prio,int preauth)357 void pmksa_candidate_add(struct wpa_sm *sm, const u8 *bssid,
358 int prio, int preauth)
359 {
360 struct rsn_pmksa_candidate *cand, *prev, *pos;
361
362 if (sm->cur_ssid && sm->cur_ssid->proactive_key_caching)
363 pmksa_cache_get_opportunistic(sm->pmksa, sm->cur_ssid, bssid);
364
365 if (!preauth) {
366 wpa_printf(MSG_DEBUG, "RSN: Ignored PMKID candidate without "
367 "preauth flag");
368 return;
369 }
370
371 /* If BSSID already on candidate list, update the priority of the old
372 * entry. Do not override priority based on normal scan results. */
373 prev = NULL;
374 cand = sm->pmksa_candidates;
375 while (cand) {
376 if (os_memcmp(cand->bssid, bssid, ETH_ALEN) == 0) {
377 if (prev)
378 prev->next = cand->next;
379 else
380 sm->pmksa_candidates = cand->next;
381 break;
382 }
383 prev = cand;
384 cand = cand->next;
385 }
386
387 if (cand) {
388 if (prio < PMKID_CANDIDATE_PRIO_SCAN)
389 cand->priority = prio;
390 } else {
391 cand = os_zalloc(sizeof(*cand));
392 if (cand == NULL)
393 return;
394 os_memcpy(cand->bssid, bssid, ETH_ALEN);
395 cand->priority = prio;
396 }
397
398 /* Add candidate to the list; order by increasing priority value. i.e.,
399 * highest priority (smallest value) first. */
400 prev = NULL;
401 pos = sm->pmksa_candidates;
402 while (pos) {
403 if (cand->priority <= pos->priority)
404 break;
405 prev = pos;
406 pos = pos->next;
407 }
408 cand->next = pos;
409 if (prev)
410 prev->next = cand;
411 else
412 sm->pmksa_candidates = cand;
413
414 wpa_msg(sm->ctx->ctx, MSG_DEBUG, "RSN: added PMKSA cache "
415 "candidate " MACSTR " prio %d", MAC2STR(bssid), prio);
416 rsn_preauth_candidate_process(sm);
417 }
418
419
420 /* TODO: schedule periodic scans if current AP supports preauth */
421
422 /**
423 * rsn_preauth_scan_results - Process scan results to find PMKSA candidates
424 * @sm: Pointer to WPA state machine data from wpa_sm_init()
425 * @results: Scan results
426 * @count: Number of BSSes in scan results
427 *
428 * This functions goes through the scan results and adds all suitable APs
429 * (Authenticators) into PMKSA candidate list.
430 */
rsn_preauth_scan_results(struct wpa_sm * sm,struct wpa_scan_result * results,int count)431 void rsn_preauth_scan_results(struct wpa_sm *sm,
432 struct wpa_scan_result *results, int count)
433 {
434 struct wpa_scan_result *r;
435 struct wpa_ie_data ie;
436 int i;
437 struct rsn_pmksa_cache_entry *pmksa;
438
439 if (sm->cur_ssid == NULL)
440 return;
441
442 /*
443 * TODO: is it ok to free all candidates? What about the entries
444 * received from EVENT_PMKID_CANDIDATE?
445 */
446 pmksa_candidate_free(sm);
447
448 for (i = count - 1; i >= 0; i--) {
449 r = &results[i];
450 if (r->ssid_len != sm->cur_ssid->ssid_len ||
451 os_memcmp(r->ssid, sm->cur_ssid->ssid,
452 r->ssid_len) != 0)
453 continue;
454
455 if (os_memcmp(r->bssid, sm->bssid, ETH_ALEN) == 0)
456 continue;
457
458 if (r->rsn_ie_len == 0 ||
459 wpa_parse_wpa_ie(r->rsn_ie, r->rsn_ie_len, &ie))
460 continue;
461
462 pmksa = pmksa_cache_get(sm->pmksa, r->bssid, NULL);
463 if (pmksa &&
464 (!pmksa->opportunistic ||
465 !(ie.capabilities & WPA_CAPABILITY_PREAUTH)))
466 continue;
467
468 /*
469 * Give less priority to candidates found from normal
470 * scan results.
471 */
472 pmksa_candidate_add(sm, r->bssid,
473 PMKID_CANDIDATE_PRIO_SCAN,
474 ie.capabilities & WPA_CAPABILITY_PREAUTH);
475 }
476 }
477
478
479 #ifdef CONFIG_CTRL_IFACE
480 /**
481 * rsn_preauth_get_status - Get pre-authentication status
482 * @sm: Pointer to WPA state machine data from wpa_sm_init()
483 * @buf: Buffer for status information
484 * @buflen: Maximum buffer length
485 * @verbose: Whether to include verbose status information
486 * Returns: Number of bytes written to buf.
487 *
488 * Query WPA2 pre-authentication for status information. This function fills in
489 * a text area with current status information. If the buffer (buf) is not
490 * large enough, status information will be truncated to fit the buffer.
491 */
rsn_preauth_get_status(struct wpa_sm * sm,char * buf,size_t buflen,int verbose)492 int rsn_preauth_get_status(struct wpa_sm *sm, char *buf, size_t buflen,
493 int verbose)
494 {
495 char *pos = buf, *end = buf + buflen;
496 int res, ret;
497
498 if (sm->preauth_eapol) {
499 ret = os_snprintf(pos, end - pos, "Pre-authentication "
500 "EAPOL state machines:\n");
501 if (ret < 0 || ret >= end - pos)
502 return pos - buf;
503 pos += ret;
504 res = eapol_sm_get_status(sm->preauth_eapol,
505 pos, end - pos, verbose);
506 if (res >= 0)
507 pos += res;
508 }
509
510 return pos - buf;
511 }
512 #endif /* CONFIG_CTRL_IFACE */
513
514
515 /**
516 * rsn_preauth_in_progress - Verify whether pre-authentication is in progress
517 * @sm: Pointer to WPA state machine data from wpa_sm_init()
518 */
rsn_preauth_in_progress(struct wpa_sm * sm)519 int rsn_preauth_in_progress(struct wpa_sm *sm)
520 {
521 return sm->preauth_eapol != NULL;
522 }
523
524 #endif /* IEEE8021X_EAPOL and !CONFIG_NO_WPA2 */
525