Line data Source code
1 : /*
2 : * RSN pre-authentication (supplicant)
3 : * Copyright (c) 2003-2012, 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 : */
37 185 : void pmksa_candidate_free(struct wpa_sm *sm)
38 : {
39 : struct rsn_pmksa_candidate *entry, *n;
40 :
41 185 : if (sm == NULL)
42 194 : return;
43 :
44 176 : 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 4 : static void rsn_preauth_receive(void *ctx, const u8 *src_addr,
53 : const u8 *buf, size_t len)
54 : {
55 4 : struct wpa_sm *sm = ctx;
56 :
57 4 : wpa_printf(MSG_DEBUG, "RX pre-auth from " MACSTR, MAC2STR(src_addr));
58 4 : wpa_hexdump(MSG_MSGDUMP, "RX pre-auth", buf, len);
59 :
60 8 : if (sm->preauth_eapol == NULL ||
61 8 : is_zero_ether_addr(sm->preauth_bssid) ||
62 4 : 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 4 : return;
67 : }
68 :
69 4 : eapol_sm_rx_eapol(sm->preauth_eapol, src_addr, buf, len);
70 : }
71 :
72 :
73 1 : static void rsn_preauth_eapol_cb(struct eapol_sm *eapol,
74 : enum eapol_supp_result result,
75 : void *ctx)
76 : {
77 1 : struct wpa_sm *sm = ctx;
78 : u8 pmk[PMK_LEN];
79 :
80 1 : if (result == EAPOL_SUPP_RESULT_SUCCESS) {
81 : int res, pmk_len;
82 1 : pmk_len = PMK_LEN;
83 1 : res = eapol_sm_get_key(eapol, pmk, PMK_LEN);
84 1 : 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 1 : if (res == 0) {
93 1 : wpa_hexdump_key(MSG_DEBUG, "RSN: PMK from pre-auth",
94 : pmk, pmk_len);
95 1 : sm->pmk_len = pmk_len;
96 2 : pmksa_cache_add(sm->pmksa, pmk, pmk_len,
97 1 : sm->preauth_bssid, sm->own_addr,
98 : sm->network_ctx,
99 : WPA_KEY_MGMT_IEEE8021X);
100 : } else {
101 0 : wpa_msg(sm->ctx->msg_ctx, MSG_INFO,
102 : "RSN: failed to get master session key from "
103 : "pre-auth EAPOL state machines");
104 0 : result = EAPOL_SUPP_RESULT_FAILURE;
105 : }
106 : }
107 :
108 7 : wpa_msg(sm->ctx->msg_ctx, MSG_INFO, "RSN: pre-authentication with "
109 6 : MACSTR " %s", MAC2STR(sm->preauth_bssid),
110 : result == EAPOL_SUPP_RESULT_SUCCESS ? "completed successfully" :
111 : "failed");
112 :
113 1 : rsn_preauth_deinit(sm);
114 1 : rsn_preauth_candidate_process(sm);
115 1 : }
116 :
117 :
118 0 : static void rsn_preauth_timeout(void *eloop_ctx, void *timeout_ctx)
119 : {
120 0 : struct wpa_sm *sm = eloop_ctx;
121 :
122 0 : wpa_msg(sm->ctx->msg_ctx, MSG_INFO, "RSN: pre-authentication with "
123 0 : MACSTR " timed out", MAC2STR(sm->preauth_bssid));
124 0 : rsn_preauth_deinit(sm);
125 0 : rsn_preauth_candidate_process(sm);
126 0 : }
127 :
128 :
129 4 : static int rsn_preauth_eapol_send(void *ctx, int type, const u8 *buf,
130 : size_t len)
131 : {
132 4 : struct wpa_sm *sm = ctx;
133 : u8 *msg;
134 : size_t msglen;
135 : int res;
136 :
137 : /* TODO: could add l2_packet_sendmsg that allows fragments to avoid
138 : * extra copy here */
139 :
140 4 : if (sm->l2_preauth == NULL)
141 0 : return -1;
142 :
143 4 : msg = wpa_sm_alloc_eapol(sm, type, buf, len, &msglen, NULL);
144 4 : if (msg == NULL)
145 0 : return -1;
146 :
147 4 : wpa_hexdump(MSG_MSGDUMP, "TX EAPOL (preauth)", msg, msglen);
148 4 : res = l2_packet_send(sm->l2_preauth, sm->preauth_bssid,
149 : ETH_P_RSN_PREAUTH, msg, msglen);
150 4 : os_free(msg);
151 4 : return res;
152 : }
153 :
154 :
155 : /**
156 : * rsn_preauth_init - Start new RSN pre-authentication
157 : * @sm: Pointer to WPA state machine data from wpa_sm_init()
158 : * @dst: Authenticator address (BSSID) with which to preauthenticate
159 : * @eap_conf: Current EAP configuration
160 : * Returns: 0 on success, -1 on another pre-authentication is in progress,
161 : * -2 on layer 2 packet initialization failure, -3 on EAPOL state machine
162 : * initialization failure, -4 on memory allocation failure
163 : *
164 : * This function request an RSN pre-authentication with a given destination
165 : * address. This is usually called for PMKSA candidates found from scan results
166 : * or from driver reports. In addition, ctrl_iface PREAUTH command can trigger
167 : * pre-authentication.
168 : */
169 2 : int rsn_preauth_init(struct wpa_sm *sm, const u8 *dst,
170 : struct eap_peer_config *eap_conf)
171 : {
172 : struct eapol_config eapol_conf;
173 : struct eapol_ctx *ctx;
174 :
175 2 : if (sm->preauth_eapol)
176 0 : return -1;
177 :
178 12 : wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG,
179 12 : "RSN: starting pre-authentication with " MACSTR, MAC2STR(dst));
180 :
181 2 : sm->l2_preauth = l2_packet_init(sm->ifname, sm->own_addr,
182 : ETH_P_RSN_PREAUTH,
183 : rsn_preauth_receive, sm, 0);
184 2 : if (sm->l2_preauth == NULL) {
185 0 : wpa_printf(MSG_WARNING, "RSN: Failed to initialize L2 packet "
186 : "processing for pre-authentication");
187 0 : return -2;
188 : }
189 :
190 2 : if (sm->bridge_ifname) {
191 0 : sm->l2_preauth_br = l2_packet_init(sm->bridge_ifname,
192 0 : sm->own_addr,
193 : ETH_P_RSN_PREAUTH,
194 : rsn_preauth_receive, sm, 0);
195 0 : if (sm->l2_preauth_br == NULL) {
196 0 : wpa_printf(MSG_WARNING, "RSN: Failed to initialize L2 "
197 : "packet processing (bridge) for "
198 : "pre-authentication");
199 0 : return -2;
200 : }
201 : }
202 :
203 2 : ctx = os_zalloc(sizeof(*ctx));
204 2 : if (ctx == NULL) {
205 0 : wpa_printf(MSG_WARNING, "Failed to allocate EAPOL context.");
206 0 : return -4;
207 : }
208 2 : ctx->ctx = sm->ctx->ctx;
209 2 : ctx->msg_ctx = sm->ctx->ctx;
210 2 : ctx->preauth = 1;
211 2 : ctx->cb = rsn_preauth_eapol_cb;
212 2 : ctx->cb_ctx = sm;
213 2 : ctx->scard_ctx = sm->scard_ctx;
214 2 : ctx->eapol_send = rsn_preauth_eapol_send;
215 2 : ctx->eapol_send_ctx = sm;
216 2 : ctx->set_config_blob = sm->ctx->set_config_blob;
217 2 : ctx->get_config_blob = sm->ctx->get_config_blob;
218 :
219 2 : sm->preauth_eapol = eapol_sm_init(ctx);
220 2 : if (sm->preauth_eapol == NULL) {
221 0 : os_free(ctx);
222 0 : wpa_printf(MSG_WARNING, "RSN: Failed to initialize EAPOL "
223 : "state machines for pre-authentication");
224 0 : return -3;
225 : }
226 2 : os_memset(&eapol_conf, 0, sizeof(eapol_conf));
227 2 : eapol_conf.accept_802_1x_keys = 0;
228 2 : eapol_conf.required_keys = 0;
229 2 : eapol_conf.fast_reauth = sm->fast_reauth;
230 2 : eapol_conf.workaround = sm->eap_workaround;
231 2 : eapol_sm_notify_config(sm->preauth_eapol, eap_conf, &eapol_conf);
232 : /*
233 : * Use a shorter startPeriod with preauthentication since the first
234 : * preauth EAPOL-Start frame may end up being dropped due to race
235 : * condition in the AP between the data receive and key configuration
236 : * after the 4-Way Handshake.
237 : */
238 2 : eapol_sm_configure(sm->preauth_eapol, -1, -1, 5, 6);
239 2 : os_memcpy(sm->preauth_bssid, dst, ETH_ALEN);
240 :
241 2 : eapol_sm_notify_portValid(sm->preauth_eapol, TRUE);
242 : /* 802.1X::portControl = Auto */
243 2 : eapol_sm_notify_portEnabled(sm->preauth_eapol, TRUE);
244 :
245 2 : eloop_register_timeout(sm->dot11RSNAConfigSATimeout, 0,
246 : rsn_preauth_timeout, sm, NULL);
247 :
248 2 : return 0;
249 : }
250 :
251 :
252 : /**
253 : * rsn_preauth_deinit - Abort RSN pre-authentication
254 : * @sm: Pointer to WPA state machine data from wpa_sm_init()
255 : *
256 : * This function aborts the current RSN pre-authentication (if one is started)
257 : * and frees resources allocated for it.
258 : */
259 1162 : void rsn_preauth_deinit(struct wpa_sm *sm)
260 : {
261 1162 : if (sm == NULL || !sm->preauth_eapol)
262 2322 : return;
263 :
264 2 : eloop_cancel_timeout(rsn_preauth_timeout, sm, NULL);
265 2 : eapol_sm_deinit(sm->preauth_eapol);
266 2 : sm->preauth_eapol = NULL;
267 2 : os_memset(sm->preauth_bssid, 0, ETH_ALEN);
268 :
269 2 : l2_packet_deinit(sm->l2_preauth);
270 2 : sm->l2_preauth = NULL;
271 2 : if (sm->l2_preauth_br) {
272 0 : l2_packet_deinit(sm->l2_preauth_br);
273 0 : sm->l2_preauth_br = NULL;
274 : }
275 : }
276 :
277 :
278 : /**
279 : * rsn_preauth_candidate_process - Process PMKSA candidates
280 : * @sm: Pointer to WPA state machine data from wpa_sm_init()
281 : *
282 : * Go through the PMKSA candidates and start pre-authentication if a candidate
283 : * without an existing PMKSA cache entry is found. Processed candidates will be
284 : * removed from the list.
285 : */
286 624 : void rsn_preauth_candidate_process(struct wpa_sm *sm)
287 : {
288 : struct rsn_pmksa_candidate *candidate, *n;
289 :
290 624 : if (dl_list_empty(&sm->pmksa_candidates))
291 623 : return;
292 :
293 : /* TODO: drop priority for old candidate entries */
294 :
295 1 : wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: processing PMKSA candidate "
296 : "list");
297 2 : if (sm->preauth_eapol ||
298 2 : sm->proto != WPA_PROTO_RSN ||
299 2 : wpa_sm_get_state(sm) != WPA_COMPLETED ||
300 1 : (sm->key_mgmt != WPA_KEY_MGMT_IEEE8021X &&
301 0 : sm->key_mgmt != WPA_KEY_MGMT_IEEE8021X_SHA256)) {
302 0 : wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: not in suitable "
303 : "state for new pre-authentication");
304 0 : return; /* invalid state for new pre-auth */
305 : }
306 :
307 1 : dl_list_for_each_safe(candidate, n, &sm->pmksa_candidates,
308 : struct rsn_pmksa_candidate, list) {
309 1 : struct rsn_pmksa_cache_entry *p = NULL;
310 1 : p = pmksa_cache_get(sm->pmksa, candidate->bssid, NULL, NULL);
311 1 : if (os_memcmp(sm->bssid, candidate->bssid, ETH_ALEN) != 0 &&
312 0 : (p == NULL || p->opportunistic)) {
313 6 : wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: PMKSA "
314 : "candidate " MACSTR
315 : " selected for pre-authentication",
316 6 : MAC2STR(candidate->bssid));
317 1 : dl_list_del(&candidate->list);
318 1 : rsn_preauth_init(sm, candidate->bssid,
319 1 : sm->eap_conf_ctx);
320 1 : os_free(candidate);
321 1 : return;
322 : }
323 0 : wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: PMKSA candidate "
324 : MACSTR " does not need pre-authentication anymore",
325 0 : MAC2STR(candidate->bssid));
326 : /* Some drivers (e.g., NDIS) expect to get notified about the
327 : * PMKIDs again, so report the existing data now. */
328 0 : if (p) {
329 0 : wpa_sm_add_pmkid(sm, candidate->bssid, p->pmkid);
330 : }
331 :
332 0 : dl_list_del(&candidate->list);
333 0 : os_free(candidate);
334 : }
335 0 : wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: no more pending PMKSA "
336 : "candidates");
337 : }
338 :
339 :
340 : /**
341 : * pmksa_candidate_add - Add a new PMKSA candidate
342 : * @sm: Pointer to WPA state machine data from wpa_sm_init()
343 : * @bssid: BSSID (authenticator address) of the candidate
344 : * @prio: Priority (the smaller number, the higher priority)
345 : * @preauth: Whether the candidate AP advertises support for pre-authentication
346 : *
347 : * This function is used to add PMKSA candidates for RSN pre-authentication. It
348 : * is called from scan result processing and from driver events for PMKSA
349 : * candidates, i.e., EVENT_PMKID_CANDIDATE events to wpa_supplicant_event().
350 : */
351 10 : void pmksa_candidate_add(struct wpa_sm *sm, const u8 *bssid,
352 : int prio, int preauth)
353 : {
354 : struct rsn_pmksa_candidate *cand, *pos;
355 :
356 10 : if (sm->network_ctx && sm->proactive_key_caching)
357 3 : pmksa_cache_get_opportunistic(sm->pmksa, sm->network_ctx,
358 : bssid);
359 :
360 10 : if (!preauth) {
361 9 : wpa_printf(MSG_DEBUG, "RSN: Ignored PMKID candidate without "
362 : "preauth flag");
363 9 : return;
364 : }
365 :
366 : /* If BSSID already on candidate list, update the priority of the old
367 : * entry. Do not override priority based on normal scan results. */
368 1 : cand = NULL;
369 1 : dl_list_for_each(pos, &sm->pmksa_candidates,
370 : struct rsn_pmksa_candidate, list) {
371 0 : if (os_memcmp(pos->bssid, bssid, ETH_ALEN) == 0) {
372 0 : cand = pos;
373 0 : break;
374 : }
375 : }
376 :
377 1 : if (cand) {
378 0 : dl_list_del(&cand->list);
379 0 : if (prio < PMKID_CANDIDATE_PRIO_SCAN)
380 0 : cand->priority = prio;
381 : } else {
382 1 : cand = os_zalloc(sizeof(*cand));
383 1 : if (cand == NULL)
384 0 : return;
385 1 : os_memcpy(cand->bssid, bssid, ETH_ALEN);
386 1 : cand->priority = prio;
387 : }
388 :
389 : /* Add candidate to the list; order by increasing priority value. i.e.,
390 : * highest priority (smallest value) first. */
391 1 : dl_list_for_each(pos, &sm->pmksa_candidates,
392 : struct rsn_pmksa_candidate, list) {
393 0 : if (cand->priority <= pos->priority) {
394 0 : dl_list_add(pos->list.prev, &cand->list);
395 0 : cand = NULL;
396 0 : break;
397 : }
398 : }
399 1 : if (cand)
400 1 : dl_list_add_tail(&sm->pmksa_candidates, &cand->list);
401 :
402 6 : wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: added PMKSA cache "
403 6 : "candidate " MACSTR " prio %d", MAC2STR(bssid), prio);
404 1 : rsn_preauth_candidate_process(sm);
405 : }
406 :
407 :
408 : /* TODO: schedule periodic scans if current AP supports preauth */
409 :
410 : /**
411 : * rsn_preauth_scan_results - Start processing scan results for canditates
412 : * @sm: Pointer to WPA state machine data from wpa_sm_init()
413 : * Returns: 0 if ready to process results or -1 to skip processing
414 : *
415 : * This functions is used to notify RSN code about start of new scan results
416 : * processing. The actual scan results will be provided by calling
417 : * rsn_preauth_scan_result() for each BSS if this function returned 0.
418 : */
419 744 : int rsn_preauth_scan_results(struct wpa_sm *sm)
420 : {
421 744 : if (sm->ssid_len == 0)
422 637 : return -1;
423 :
424 : /*
425 : * TODO: is it ok to free all candidates? What about the entries
426 : * received from EVENT_PMKID_CANDIDATE?
427 : */
428 107 : pmksa_candidate_free(sm);
429 :
430 107 : return 0;
431 : }
432 :
433 :
434 : /**
435 : * rsn_preauth_scan_result - Processing scan result for PMKSA canditates
436 : * @sm: Pointer to WPA state machine data from wpa_sm_init()
437 : *
438 : * Add all suitable APs (Authenticators) from scan results into PMKSA
439 : * candidate list.
440 : */
441 91 : void rsn_preauth_scan_result(struct wpa_sm *sm, const u8 *bssid,
442 : const u8 *ssid, const u8 *rsn)
443 : {
444 : struct wpa_ie_data ie;
445 : struct rsn_pmksa_cache_entry *pmksa;
446 :
447 177 : if (ssid[1] != sm->ssid_len ||
448 86 : os_memcmp(ssid + 2, sm->ssid, sm->ssid_len) != 0)
449 90 : return; /* Not for the current SSID */
450 :
451 82 : if (os_memcmp(bssid, sm->bssid, ETH_ALEN) == 0)
452 67 : return; /* Ignore current AP */
453 :
454 15 : if (wpa_parse_wpa_ie(rsn, 2 + rsn[1], &ie))
455 0 : return;
456 :
457 15 : pmksa = pmksa_cache_get(sm->pmksa, bssid, NULL, NULL);
458 15 : if (pmksa && (!pmksa->opportunistic ||
459 0 : !(ie.capabilities & WPA_CAPABILITY_PREAUTH)))
460 5 : return;
461 :
462 : /* Give less priority to candidates found from normal scan results. */
463 10 : pmksa_candidate_add(sm, bssid, PMKID_CANDIDATE_PRIO_SCAN,
464 10 : ie.capabilities & WPA_CAPABILITY_PREAUTH);
465 : }
466 :
467 :
468 : #ifdef CONFIG_CTRL_IFACE
469 : /**
470 : * rsn_preauth_get_status - Get pre-authentication status
471 : * @sm: Pointer to WPA state machine data from wpa_sm_init()
472 : * @buf: Buffer for status information
473 : * @buflen: Maximum buffer length
474 : * @verbose: Whether to include verbose status information
475 : * Returns: Number of bytes written to buf.
476 : *
477 : * Query WPA2 pre-authentication for status information. This function fills in
478 : * a text area with current status information. If the buffer (buf) is not
479 : * large enough, status information will be truncated to fit the buffer.
480 : */
481 755 : int rsn_preauth_get_status(struct wpa_sm *sm, char *buf, size_t buflen,
482 : int verbose)
483 : {
484 755 : char *pos = buf, *end = buf + buflen;
485 : int res, ret;
486 :
487 755 : if (sm->preauth_eapol) {
488 1 : ret = os_snprintf(pos, end - pos, "Pre-authentication "
489 : "EAPOL state machines:\n");
490 1 : if (ret < 0 || ret >= end - pos)
491 0 : return pos - buf;
492 1 : pos += ret;
493 1 : res = eapol_sm_get_status(sm->preauth_eapol,
494 1 : pos, end - pos, verbose);
495 1 : if (res >= 0)
496 1 : pos += res;
497 : }
498 :
499 755 : return pos - buf;
500 : }
501 : #endif /* CONFIG_CTRL_IFACE */
502 :
503 :
504 : /**
505 : * rsn_preauth_in_progress - Verify whether pre-authentication is in progress
506 : * @sm: Pointer to WPA state machine data from wpa_sm_init()
507 : */
508 0 : int rsn_preauth_in_progress(struct wpa_sm *sm)
509 : {
510 0 : return sm->preauth_eapol != NULL;
511 : }
512 :
513 : #endif /* IEEE8021X_EAPOL */
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