2 * WPA Supplicant - RSN PMKSA cache
3 * Copyright (c) 2004-2008, Jouni Malinen <j@w1.fi>
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.
9 * Alternatively, this software may be distributed under the terms of BSD
12 * See README and COPYING for more details.
19 #include "eapol_supp/eapol_supp_sm.h"
22 #include "pmksa_cache.h"
24 #if defined(IEEE8021X_EAPOL) && !defined(CONFIG_NO_WPA2)
26 static const int pmksa_cache_max_entries = 32;
28 struct rsn_pmksa_cache {
29 struct rsn_pmksa_cache_entry *pmksa; /* PMKSA cache */
30 int pmksa_count; /* number of entries in PMKSA cache */
31 struct wpa_sm *sm; /* TODO: get rid of this reference(?) */
33 void (*free_cb)(struct rsn_pmksa_cache_entry *entry, void *ctx,
39 static void pmksa_cache_set_expiration(struct rsn_pmksa_cache *pmksa);
42 static void _pmksa_cache_free_entry(struct rsn_pmksa_cache_entry *entry)
48 static void pmksa_cache_free_entry(struct rsn_pmksa_cache *pmksa,
49 struct rsn_pmksa_cache_entry *entry,
53 pmksa->free_cb(entry, pmksa->ctx, replace);
54 _pmksa_cache_free_entry(entry);
58 static void pmksa_cache_expire(void *eloop_ctx, void *timeout_ctx)
60 struct rsn_pmksa_cache *pmksa = eloop_ctx;
64 while (pmksa->pmksa && pmksa->pmksa->expiration <= now.sec) {
65 struct rsn_pmksa_cache_entry *entry = pmksa->pmksa;
66 pmksa->pmksa = entry->next;
67 wpa_printf(MSG_DEBUG, "RSN: expired PMKSA cache entry for "
68 MACSTR, MAC2STR(entry->aa));
69 wpa_sm_remove_pmkid(pmksa->sm, entry->aa, entry->pmkid);
70 pmksa_cache_free_entry(pmksa, entry, 0);
73 pmksa_cache_set_expiration(pmksa);
77 static void pmksa_cache_reauth(void *eloop_ctx, void *timeout_ctx)
79 struct rsn_pmksa_cache *pmksa = eloop_ctx;
80 pmksa->sm->cur_pmksa = NULL;
81 eapol_sm_request_reauth(pmksa->sm->eapol);
85 static void pmksa_cache_set_expiration(struct rsn_pmksa_cache *pmksa)
88 struct rsn_pmksa_cache_entry *entry;
91 eloop_cancel_timeout(pmksa_cache_expire, pmksa, NULL);
92 eloop_cancel_timeout(pmksa_cache_reauth, pmksa, NULL);
93 if (pmksa->pmksa == NULL)
96 sec = pmksa->pmksa->expiration - now.sec;
99 eloop_register_timeout(sec + 1, 0, pmksa_cache_expire, pmksa, NULL);
101 entry = pmksa->sm->cur_pmksa ? pmksa->sm->cur_pmksa :
102 pmksa_cache_get(pmksa, pmksa->sm->bssid, NULL);
104 sec = pmksa->pmksa->reauth_time - now.sec;
107 eloop_register_timeout(sec, 0, pmksa_cache_reauth, pmksa,
114 * pmksa_cache_add - Add a PMKSA cache entry
115 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
116 * @pmk: The new pairwise master key
117 * @pmk_len: PMK length in bytes, usually PMK_LEN (32)
118 * @aa: Authenticator address
119 * @spa: Supplicant address
120 * @network_ctx: Network configuration context for this PMK
121 * @akmp: WPA_KEY_MGMT_* used in key derivation
122 * Returns: Pointer to the added PMKSA cache entry or %NULL on error
124 * This function create a PMKSA entry for a new PMK and adds it to the PMKSA
125 * cache. If an old entry is already in the cache for the same Authenticator,
126 * this entry will be replaced with the new entry. PMKID will be calculated
127 * based on the PMK and the driver interface is notified of the new PMKID.
129 struct rsn_pmksa_cache_entry *
130 pmksa_cache_add(struct rsn_pmksa_cache *pmksa, const u8 *pmk, size_t pmk_len,
131 const u8 *aa, const u8 *spa, void *network_ctx, int akmp)
133 struct rsn_pmksa_cache_entry *entry, *pos, *prev;
136 if (pmk_len > PMK_LEN)
139 entry = os_zalloc(sizeof(*entry));
142 os_memcpy(entry->pmk, pmk, pmk_len);
143 entry->pmk_len = pmk_len;
144 rsn_pmkid(pmk, pmk_len, aa, spa, entry->pmkid,
145 wpa_key_mgmt_sha256(akmp));
147 entry->expiration = now.sec + pmksa->sm->dot11RSNAConfigPMKLifetime;
148 entry->reauth_time = now.sec + pmksa->sm->dot11RSNAConfigPMKLifetime *
149 pmksa->sm->dot11RSNAConfigPMKReauthThreshold / 100;
151 os_memcpy(entry->aa, aa, ETH_ALEN);
152 entry->network_ctx = network_ctx;
154 /* Replace an old entry for the same Authenticator (if found) with the
159 if (os_memcmp(aa, pos->aa, ETH_ALEN) == 0) {
160 if (pos->pmk_len == pmk_len &&
161 os_memcmp(pos->pmk, pmk, pmk_len) == 0 &&
162 os_memcmp(pos->pmkid, entry->pmkid, PMKID_LEN) ==
164 wpa_printf(MSG_DEBUG, "WPA: reusing previous "
170 pmksa->pmksa = pos->next;
172 prev->next = pos->next;
173 if (pos == pmksa->sm->cur_pmksa) {
174 /* We are about to replace the current PMKSA
175 * cache entry. This happens when the PMKSA
176 * caching attempt fails, so we don't want to
177 * force pmksa_cache_free_entry() to disconnect
178 * at this point. Let's just make sure the old
179 * PMKSA cache entry will not be used in the
182 wpa_printf(MSG_DEBUG, "RSN: replacing current "
184 pmksa->sm->cur_pmksa = NULL;
186 wpa_printf(MSG_DEBUG, "RSN: Replace PMKSA entry for "
188 pmksa_cache_free_entry(pmksa, pos, 1);
191 * If OKC is used, there may be other PMKSA cache
192 * entries based on the same PMK. These needs to be
193 * flushed so that a new entry can be created based on
196 pmksa_cache_flush(pmksa, network_ctx);
203 if (pmksa->pmksa_count >= pmksa_cache_max_entries && pmksa->pmksa) {
204 /* Remove the oldest entry to make room for the new entry */
206 pmksa->pmksa = pos->next;
207 wpa_printf(MSG_DEBUG, "RSN: removed the oldest PMKSA cache "
208 "entry (for " MACSTR ") to make room for new one",
210 wpa_sm_remove_pmkid(pmksa->sm, pos->aa, pos->pmkid);
211 pmksa_cache_free_entry(pmksa, pos, 0);
214 /* Add the new entry; order by expiration time */
218 if (pos->expiration > entry->expiration)
224 entry->next = pmksa->pmksa;
225 pmksa->pmksa = entry;
226 pmksa_cache_set_expiration(pmksa);
228 entry->next = prev->next;
231 pmksa->pmksa_count++;
232 wpa_printf(MSG_DEBUG, "RSN: added PMKSA cache entry for " MACSTR,
234 wpa_sm_add_pmkid(pmksa->sm, entry->aa, entry->pmkid);
241 * pmksa_cache_flush - Flush PMKSA cache entries for a specific network
242 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
243 * @network_ctx: Network configuration context or %NULL to flush all entries
245 void pmksa_cache_flush(struct rsn_pmksa_cache *pmksa, void *network_ctx)
247 struct rsn_pmksa_cache_entry *entry, *prev = NULL, *tmp;
250 entry = pmksa->pmksa;
252 if (entry->network_ctx == network_ctx || network_ctx == NULL) {
253 wpa_printf(MSG_DEBUG, "RSN: Flush PMKSA cache entry "
254 "for " MACSTR, MAC2STR(entry->aa));
256 prev->next = entry->next;
258 pmksa->pmksa = entry->next;
261 wpa_sm_remove_pmkid(pmksa->sm, tmp->aa, tmp->pmkid);
262 pmksa_cache_free_entry(pmksa, tmp, 0);
270 pmksa_cache_set_expiration(pmksa);
275 * pmksa_cache_deinit - Free all entries in PMKSA cache
276 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
278 void pmksa_cache_deinit(struct rsn_pmksa_cache *pmksa)
280 struct rsn_pmksa_cache_entry *entry, *prev;
285 entry = pmksa->pmksa;
292 pmksa_cache_set_expiration(pmksa);
298 * pmksa_cache_get - Fetch a PMKSA cache entry
299 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
300 * @aa: Authenticator address or %NULL to match any
301 * @pmkid: PMKID or %NULL to match any
302 * Returns: Pointer to PMKSA cache entry or %NULL if no match was found
304 struct rsn_pmksa_cache_entry * pmksa_cache_get(struct rsn_pmksa_cache *pmksa,
305 const u8 *aa, const u8 *pmkid)
307 struct rsn_pmksa_cache_entry *entry = pmksa->pmksa;
309 if ((aa == NULL || os_memcmp(entry->aa, aa, ETH_ALEN) == 0) &&
311 os_memcmp(entry->pmkid, pmkid, PMKID_LEN) == 0))
319 static struct rsn_pmksa_cache_entry *
320 pmksa_cache_clone_entry(struct rsn_pmksa_cache *pmksa,
321 const struct rsn_pmksa_cache_entry *old_entry,
324 struct rsn_pmksa_cache_entry *new_entry;
326 new_entry = pmksa_cache_add(pmksa, old_entry->pmk, old_entry->pmk_len,
327 aa, pmksa->sm->own_addr,
328 old_entry->network_ctx, old_entry->akmp);
329 if (new_entry == NULL)
332 /* TODO: reorder entries based on expiration time? */
333 new_entry->expiration = old_entry->expiration;
334 new_entry->opportunistic = 1;
341 * pmksa_cache_get_opportunistic - Try to get an opportunistic PMKSA entry
342 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
343 * @network_ctx: Network configuration context
344 * @aa: Authenticator address for the new AP
345 * Returns: Pointer to a new PMKSA cache entry or %NULL if not available
347 * Try to create a new PMKSA cache entry opportunistically by guessing that the
348 * new AP is sharing the same PMK as another AP that has the same SSID and has
349 * already an entry in PMKSA cache.
351 struct rsn_pmksa_cache_entry *
352 pmksa_cache_get_opportunistic(struct rsn_pmksa_cache *pmksa, void *network_ctx,
355 struct rsn_pmksa_cache_entry *entry = pmksa->pmksa;
357 wpa_printf(MSG_DEBUG, "RSN: Consider " MACSTR " for OKC", MAC2STR(aa));
358 if (network_ctx == NULL)
361 if (entry->network_ctx == network_ctx) {
362 entry = pmksa_cache_clone_entry(pmksa, entry, aa);
364 wpa_printf(MSG_DEBUG, "RSN: added "
365 "opportunistic PMKSA cache entry "
366 "for " MACSTR, MAC2STR(aa));
377 * pmksa_cache_get_current - Get the current used PMKSA entry
378 * @sm: Pointer to WPA state machine data from wpa_sm_init()
379 * Returns: Pointer to the current PMKSA cache entry or %NULL if not available
381 struct rsn_pmksa_cache_entry * pmksa_cache_get_current(struct wpa_sm *sm)
385 return sm->cur_pmksa;
390 * pmksa_cache_clear_current - Clear the current PMKSA entry selection
391 * @sm: Pointer to WPA state machine data from wpa_sm_init()
393 void pmksa_cache_clear_current(struct wpa_sm *sm)
397 sm->cur_pmksa = NULL;
402 * pmksa_cache_set_current - Set the current PMKSA entry selection
403 * @sm: Pointer to WPA state machine data from wpa_sm_init()
404 * @pmkid: PMKID for selecting PMKSA or %NULL if not used
405 * @bssid: BSSID for PMKSA or %NULL if not used
406 * @network_ctx: Network configuration context
407 * @try_opportunistic: Whether to allow opportunistic PMKSA caching
408 * Returns: 0 if PMKSA was found or -1 if no matching entry was found
410 int pmksa_cache_set_current(struct wpa_sm *sm, const u8 *pmkid,
411 const u8 *bssid, void *network_ctx,
412 int try_opportunistic)
414 struct rsn_pmksa_cache *pmksa = sm->pmksa;
415 sm->cur_pmksa = NULL;
417 sm->cur_pmksa = pmksa_cache_get(pmksa, NULL, pmkid);
418 if (sm->cur_pmksa == NULL && bssid)
419 sm->cur_pmksa = pmksa_cache_get(pmksa, bssid, NULL);
420 if (sm->cur_pmksa == NULL && try_opportunistic && bssid)
421 sm->cur_pmksa = pmksa_cache_get_opportunistic(pmksa,
425 wpa_hexdump(MSG_DEBUG, "RSN: PMKID",
426 sm->cur_pmksa->pmkid, PMKID_LEN);
434 * pmksa_cache_list - Dump text list of entries in PMKSA cache
435 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
436 * @buf: Buffer for the list
437 * @len: Length of the buffer
438 * Returns: number of bytes written to buffer
440 * This function is used to generate a text format representation of the
441 * current PMKSA cache contents for the ctrl_iface PMKSA command.
443 int pmksa_cache_list(struct rsn_pmksa_cache *pmksa, char *buf, size_t len)
447 struct rsn_pmksa_cache_entry *entry;
451 ret = os_snprintf(pos, buf + len - pos,
452 "Index / AA / PMKID / expiration (in seconds) / "
454 if (ret < 0 || ret >= buf + len - pos)
458 entry = pmksa->pmksa;
461 ret = os_snprintf(pos, buf + len - pos, "%d " MACSTR " ",
462 i, MAC2STR(entry->aa));
463 if (ret < 0 || ret >= buf + len - pos)
466 pos += wpa_snprintf_hex(pos, buf + len - pos, entry->pmkid,
468 ret = os_snprintf(pos, buf + len - pos, " %d %d\n",
469 (int) (entry->expiration - now.sec),
470 entry->opportunistic);
471 if (ret < 0 || ret >= buf + len - pos)
481 * pmksa_cache_init - Initialize PMKSA cache
482 * @free_cb: Callback function to be called when a PMKSA cache entry is freed
483 * @ctx: Context pointer for free_cb function
484 * @sm: Pointer to WPA state machine data from wpa_sm_init()
485 * Returns: Pointer to PMKSA cache data or %NULL on failure
487 struct rsn_pmksa_cache *
488 pmksa_cache_init(void (*free_cb)(struct rsn_pmksa_cache_entry *entry,
489 void *ctx, int replace),
490 void *ctx, struct wpa_sm *sm)
492 struct rsn_pmksa_cache *pmksa;
494 pmksa = os_zalloc(sizeof(*pmksa));
496 pmksa->free_cb = free_cb;
504 #endif /* IEEE8021X_EAPOL and !CONFIG_NO_WPA2 */