2 * WPA Supplicant - RSN PMKSA cache
3 * Copyright (c) 2004-2009, 2011-2012, Jouni Malinen <j@w1.fi>
5 * This software may be distributed under the terms of the BSD license.
6 * See README for more details.
13 #include "eapol_supp/eapol_supp_sm.h"
16 #include "pmksa_cache.h"
18 #if defined(IEEE8021X_EAPOL) && !defined(CONFIG_NO_WPA2)
20 static const int pmksa_cache_max_entries = 32;
22 struct rsn_pmksa_cache {
23 struct rsn_pmksa_cache_entry *pmksa; /* PMKSA cache */
24 int pmksa_count; /* number of entries in PMKSA cache */
25 struct wpa_sm *sm; /* TODO: get rid of this reference(?) */
27 void (*free_cb)(struct rsn_pmksa_cache_entry *entry, void *ctx,
33 static void pmksa_cache_set_expiration(struct rsn_pmksa_cache *pmksa);
36 static void _pmksa_cache_free_entry(struct rsn_pmksa_cache_entry *entry)
42 static void pmksa_cache_free_entry(struct rsn_pmksa_cache *pmksa,
43 struct rsn_pmksa_cache_entry *entry,
46 wpa_sm_remove_pmkid(pmksa->sm, entry->aa, entry->pmkid);
48 pmksa->free_cb(entry, pmksa->ctx, replace);
49 _pmksa_cache_free_entry(entry);
53 static void pmksa_cache_expire(void *eloop_ctx, void *timeout_ctx)
55 struct rsn_pmksa_cache *pmksa = eloop_ctx;
59 while (pmksa->pmksa && pmksa->pmksa->expiration <= now.sec) {
60 struct rsn_pmksa_cache_entry *entry = pmksa->pmksa;
61 pmksa->pmksa = entry->next;
62 wpa_printf(MSG_DEBUG, "RSN: expired PMKSA cache entry for "
63 MACSTR, MAC2STR(entry->aa));
64 pmksa_cache_free_entry(pmksa, entry, 0);
67 pmksa_cache_set_expiration(pmksa);
71 static void pmksa_cache_reauth(void *eloop_ctx, void *timeout_ctx)
73 struct rsn_pmksa_cache *pmksa = eloop_ctx;
74 pmksa->sm->cur_pmksa = NULL;
75 eapol_sm_request_reauth(pmksa->sm->eapol);
79 static void pmksa_cache_set_expiration(struct rsn_pmksa_cache *pmksa)
82 struct rsn_pmksa_cache_entry *entry;
85 eloop_cancel_timeout(pmksa_cache_expire, pmksa, NULL);
86 eloop_cancel_timeout(pmksa_cache_reauth, pmksa, NULL);
87 if (pmksa->pmksa == NULL)
90 sec = pmksa->pmksa->expiration - now.sec;
93 eloop_register_timeout(sec + 1, 0, pmksa_cache_expire, pmksa, NULL);
95 entry = pmksa->sm->cur_pmksa ? pmksa->sm->cur_pmksa :
96 pmksa_cache_get(pmksa, pmksa->sm->bssid, NULL, NULL);
98 sec = pmksa->pmksa->reauth_time - now.sec;
101 eloop_register_timeout(sec, 0, pmksa_cache_reauth, pmksa,
108 * pmksa_cache_add - Add a PMKSA cache entry
109 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
110 * @pmk: The new pairwise master key
111 * @pmk_len: PMK length in bytes, usually PMK_LEN (32)
112 * @aa: Authenticator address
113 * @spa: Supplicant address
114 * @network_ctx: Network configuration context for this PMK
115 * @akmp: WPA_KEY_MGMT_* used in key derivation
116 * Returns: Pointer to the added PMKSA cache entry or %NULL on error
118 * This function create a PMKSA entry for a new PMK and adds it to the PMKSA
119 * cache. If an old entry is already in the cache for the same Authenticator,
120 * this entry will be replaced with the new entry. PMKID will be calculated
121 * based on the PMK and the driver interface is notified of the new PMKID.
123 struct rsn_pmksa_cache_entry *
124 pmksa_cache_add(struct rsn_pmksa_cache *pmksa, const u8 *pmk, size_t pmk_len,
125 const u8 *aa, const u8 *spa, void *network_ctx, int akmp)
127 struct rsn_pmksa_cache_entry *entry, *pos, *prev;
130 if (pmk_len > PMK_LEN)
133 entry = os_zalloc(sizeof(*entry));
136 os_memcpy(entry->pmk, pmk, pmk_len);
137 entry->pmk_len = pmk_len;
138 rsn_pmkid(pmk, pmk_len, aa, spa, entry->pmkid,
139 wpa_key_mgmt_sha256(akmp));
141 entry->expiration = now.sec + pmksa->sm->dot11RSNAConfigPMKLifetime;
142 entry->reauth_time = now.sec + pmksa->sm->dot11RSNAConfigPMKLifetime *
143 pmksa->sm->dot11RSNAConfigPMKReauthThreshold / 100;
145 os_memcpy(entry->aa, aa, ETH_ALEN);
146 entry->network_ctx = network_ctx;
148 /* Replace an old entry for the same Authenticator (if found) with the
153 if (os_memcmp(aa, pos->aa, ETH_ALEN) == 0) {
154 if (pos->pmk_len == pmk_len &&
155 os_memcmp(pos->pmk, pmk, pmk_len) == 0 &&
156 os_memcmp(pos->pmkid, entry->pmkid, PMKID_LEN) ==
158 wpa_printf(MSG_DEBUG, "WPA: reusing previous "
164 pmksa->pmksa = pos->next;
166 prev->next = pos->next;
167 if (pos == pmksa->sm->cur_pmksa) {
168 /* We are about to replace the current PMKSA
169 * cache entry. This happens when the PMKSA
170 * caching attempt fails, so we don't want to
171 * force pmksa_cache_free_entry() to disconnect
172 * at this point. Let's just make sure the old
173 * PMKSA cache entry will not be used in the
176 wpa_printf(MSG_DEBUG, "RSN: replacing current "
178 pmksa->sm->cur_pmksa = NULL;
180 wpa_printf(MSG_DEBUG, "RSN: Replace PMKSA entry for "
182 pmksa_cache_free_entry(pmksa, pos, 1);
185 * If OKC is used, there may be other PMKSA cache
186 * entries based on the same PMK. These needs to be
187 * flushed so that a new entry can be created based on
190 pmksa_cache_flush(pmksa, network_ctx);
197 if (pmksa->pmksa_count >= pmksa_cache_max_entries && pmksa->pmksa) {
198 /* Remove the oldest entry to make room for the new entry */
201 if (pos == pmksa->sm->cur_pmksa) {
203 * Never remove the current PMKSA cache entry, since
204 * it's in use, and removing it triggers a needless
208 pmksa->pmksa->next = pos ? pos->next : NULL;
210 pmksa->pmksa = pos->next;
213 wpa_printf(MSG_DEBUG, "RSN: removed the oldest idle "
214 "PMKSA cache entry (for " MACSTR ") to "
215 "make room for new one",
217 pmksa_cache_free_entry(pmksa, pos, 0);
221 /* Add the new entry; order by expiration time */
225 if (pos->expiration > entry->expiration)
231 entry->next = pmksa->pmksa;
232 pmksa->pmksa = entry;
233 pmksa_cache_set_expiration(pmksa);
235 entry->next = prev->next;
238 pmksa->pmksa_count++;
239 wpa_printf(MSG_DEBUG, "RSN: Added PMKSA cache entry for " MACSTR
240 " network_ctx=%p", MAC2STR(entry->aa), network_ctx);
241 wpa_sm_add_pmkid(pmksa->sm, entry->aa, entry->pmkid);
248 * pmksa_cache_flush - Flush PMKSA cache entries for a specific network
249 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
250 * @network_ctx: Network configuration context or %NULL to flush all entries
252 void pmksa_cache_flush(struct rsn_pmksa_cache *pmksa, void *network_ctx)
254 struct rsn_pmksa_cache_entry *entry, *prev = NULL, *tmp;
257 entry = pmksa->pmksa;
259 if (entry->network_ctx == network_ctx || network_ctx == NULL) {
260 wpa_printf(MSG_DEBUG, "RSN: Flush PMKSA cache entry "
261 "for " MACSTR, MAC2STR(entry->aa));
263 prev->next = entry->next;
265 pmksa->pmksa = entry->next;
268 pmksa_cache_free_entry(pmksa, tmp, 0);
276 pmksa_cache_set_expiration(pmksa);
281 * pmksa_cache_deinit - Free all entries in PMKSA cache
282 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
284 void pmksa_cache_deinit(struct rsn_pmksa_cache *pmksa)
286 struct rsn_pmksa_cache_entry *entry, *prev;
291 entry = pmksa->pmksa;
298 pmksa_cache_set_expiration(pmksa);
304 * pmksa_cache_get - Fetch a PMKSA cache entry
305 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
306 * @aa: Authenticator address or %NULL to match any
307 * @pmkid: PMKID or %NULL to match any
308 * @network_ctx: Network context or %NULL to match any
309 * Returns: Pointer to PMKSA cache entry or %NULL if no match was found
311 struct rsn_pmksa_cache_entry * pmksa_cache_get(struct rsn_pmksa_cache *pmksa,
312 const u8 *aa, const u8 *pmkid,
313 const void *network_ctx)
315 struct rsn_pmksa_cache_entry *entry = pmksa->pmksa;
317 if ((aa == NULL || os_memcmp(entry->aa, aa, ETH_ALEN) == 0) &&
319 os_memcmp(entry->pmkid, pmkid, PMKID_LEN) == 0) &&
320 (network_ctx == NULL || network_ctx == entry->network_ctx))
328 static struct rsn_pmksa_cache_entry *
329 pmksa_cache_clone_entry(struct rsn_pmksa_cache *pmksa,
330 const struct rsn_pmksa_cache_entry *old_entry,
333 struct rsn_pmksa_cache_entry *new_entry;
335 new_entry = pmksa_cache_add(pmksa, old_entry->pmk, old_entry->pmk_len,
336 aa, pmksa->sm->own_addr,
337 old_entry->network_ctx, old_entry->akmp);
338 if (new_entry == NULL)
341 /* TODO: reorder entries based on expiration time? */
342 new_entry->expiration = old_entry->expiration;
343 new_entry->opportunistic = 1;
350 * pmksa_cache_get_opportunistic - Try to get an opportunistic PMKSA entry
351 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
352 * @network_ctx: Network configuration context
353 * @aa: Authenticator address for the new AP
354 * Returns: Pointer to a new PMKSA cache entry or %NULL if not available
356 * Try to create a new PMKSA cache entry opportunistically by guessing that the
357 * new AP is sharing the same PMK as another AP that has the same SSID and has
358 * already an entry in PMKSA cache.
360 struct rsn_pmksa_cache_entry *
361 pmksa_cache_get_opportunistic(struct rsn_pmksa_cache *pmksa, void *network_ctx,
364 struct rsn_pmksa_cache_entry *entry = pmksa->pmksa;
366 wpa_printf(MSG_DEBUG, "RSN: Consider " MACSTR " for OKC", MAC2STR(aa));
367 if (network_ctx == NULL)
370 if (entry->network_ctx == network_ctx) {
371 entry = pmksa_cache_clone_entry(pmksa, entry, aa);
373 wpa_printf(MSG_DEBUG, "RSN: added "
374 "opportunistic PMKSA cache entry "
375 "for " MACSTR, MAC2STR(aa));
386 * pmksa_cache_get_current - Get the current used PMKSA entry
387 * @sm: Pointer to WPA state machine data from wpa_sm_init()
388 * Returns: Pointer to the current PMKSA cache entry or %NULL if not available
390 struct rsn_pmksa_cache_entry * pmksa_cache_get_current(struct wpa_sm *sm)
394 return sm->cur_pmksa;
399 * pmksa_cache_clear_current - Clear the current PMKSA entry selection
400 * @sm: Pointer to WPA state machine data from wpa_sm_init()
402 void pmksa_cache_clear_current(struct wpa_sm *sm)
406 sm->cur_pmksa = NULL;
411 * pmksa_cache_set_current - Set the current PMKSA entry selection
412 * @sm: Pointer to WPA state machine data from wpa_sm_init()
413 * @pmkid: PMKID for selecting PMKSA or %NULL if not used
414 * @bssid: BSSID for PMKSA or %NULL if not used
415 * @network_ctx: Network configuration context
416 * @try_opportunistic: Whether to allow opportunistic PMKSA caching
417 * Returns: 0 if PMKSA was found or -1 if no matching entry was found
419 int pmksa_cache_set_current(struct wpa_sm *sm, const u8 *pmkid,
420 const u8 *bssid, void *network_ctx,
421 int try_opportunistic)
423 struct rsn_pmksa_cache *pmksa = sm->pmksa;
424 wpa_printf(MSG_DEBUG, "RSN: PMKSA cache search - network_ctx=%p "
425 "try_opportunistic=%d", network_ctx, try_opportunistic);
427 wpa_hexdump(MSG_DEBUG, "RSN: Search for PMKID",
430 wpa_printf(MSG_DEBUG, "RSN: Search for BSSID " MACSTR,
433 sm->cur_pmksa = NULL;
435 sm->cur_pmksa = pmksa_cache_get(pmksa, NULL, pmkid,
437 if (sm->cur_pmksa == NULL && bssid)
438 sm->cur_pmksa = pmksa_cache_get(pmksa, bssid, NULL,
440 if (sm->cur_pmksa == NULL && try_opportunistic && bssid)
441 sm->cur_pmksa = pmksa_cache_get_opportunistic(pmksa,
445 wpa_hexdump(MSG_DEBUG, "RSN: PMKSA cache entry found - PMKID",
446 sm->cur_pmksa->pmkid, PMKID_LEN);
449 wpa_printf(MSG_DEBUG, "RSN: No PMKSA cache entry found");
455 * pmksa_cache_list - Dump text list of entries in PMKSA cache
456 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
457 * @buf: Buffer for the list
458 * @len: Length of the buffer
459 * Returns: number of bytes written to buffer
461 * This function is used to generate a text format representation of the
462 * current PMKSA cache contents for the ctrl_iface PMKSA command.
464 int pmksa_cache_list(struct rsn_pmksa_cache *pmksa, char *buf, size_t len)
468 struct rsn_pmksa_cache_entry *entry;
472 ret = os_snprintf(pos, buf + len - pos,
473 "Index / AA / PMKID / expiration (in seconds) / "
475 if (ret < 0 || ret >= buf + len - pos)
479 entry = pmksa->pmksa;
482 ret = os_snprintf(pos, buf + len - pos, "%d " MACSTR " ",
483 i, MAC2STR(entry->aa));
484 if (ret < 0 || ret >= buf + len - pos)
487 pos += wpa_snprintf_hex(pos, buf + len - pos, entry->pmkid,
489 ret = os_snprintf(pos, buf + len - pos, " %d %d\n",
490 (int) (entry->expiration - now.sec),
491 entry->opportunistic);
492 if (ret < 0 || ret >= buf + len - pos)
502 * pmksa_cache_init - Initialize PMKSA cache
503 * @free_cb: Callback function to be called when a PMKSA cache entry is freed
504 * @ctx: Context pointer for free_cb function
505 * @sm: Pointer to WPA state machine data from wpa_sm_init()
506 * Returns: Pointer to PMKSA cache data or %NULL on failure
508 struct rsn_pmksa_cache *
509 pmksa_cache_init(void (*free_cb)(struct rsn_pmksa_cache_entry *entry,
510 void *ctx, int replace),
511 void *ctx, struct wpa_sm *sm)
513 struct rsn_pmksa_cache *pmksa;
515 pmksa = os_zalloc(sizeof(*pmksa));
517 pmksa->free_cb = free_cb;
525 #endif /* IEEE8021X_EAPOL and !CONFIG_NO_WPA2 */