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,
52 wpa_sm_remove_pmkid(pmksa->sm, entry->aa, entry->pmkid);
54 pmksa->free_cb(entry, pmksa->ctx, replace);
55 _pmksa_cache_free_entry(entry);
59 static void pmksa_cache_expire(void *eloop_ctx, void *timeout_ctx)
61 struct rsn_pmksa_cache *pmksa = eloop_ctx;
65 while (pmksa->pmksa && pmksa->pmksa->expiration <= now.sec) {
66 struct rsn_pmksa_cache_entry *entry = pmksa->pmksa;
67 pmksa->pmksa = entry->next;
68 wpa_printf(MSG_DEBUG, "RSN: expired PMKSA cache entry for "
69 MACSTR, MAC2STR(entry->aa));
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 pmksa_cache_free_entry(pmksa, pos, 0);
213 /* Add the new entry; order by expiration time */
217 if (pos->expiration > entry->expiration)
223 entry->next = pmksa->pmksa;
224 pmksa->pmksa = entry;
225 pmksa_cache_set_expiration(pmksa);
227 entry->next = prev->next;
230 pmksa->pmksa_count++;
231 wpa_printf(MSG_DEBUG, "RSN: added PMKSA cache entry for " MACSTR,
233 wpa_sm_add_pmkid(pmksa->sm, entry->aa, entry->pmkid);
240 * pmksa_cache_flush - Flush PMKSA cache entries for a specific network
241 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
242 * @network_ctx: Network configuration context or %NULL to flush all entries
244 void pmksa_cache_flush(struct rsn_pmksa_cache *pmksa, void *network_ctx)
246 struct rsn_pmksa_cache_entry *entry, *prev = NULL, *tmp;
249 entry = pmksa->pmksa;
251 if (entry->network_ctx == network_ctx || network_ctx == NULL) {
252 wpa_printf(MSG_DEBUG, "RSN: Flush PMKSA cache entry "
253 "for " MACSTR, MAC2STR(entry->aa));
255 prev->next = entry->next;
257 pmksa->pmksa = entry->next;
260 pmksa_cache_free_entry(pmksa, tmp, 0);
268 pmksa_cache_set_expiration(pmksa);
273 * pmksa_cache_deinit - Free all entries in PMKSA cache
274 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
276 void pmksa_cache_deinit(struct rsn_pmksa_cache *pmksa)
278 struct rsn_pmksa_cache_entry *entry, *prev;
283 entry = pmksa->pmksa;
290 pmksa_cache_set_expiration(pmksa);
296 * pmksa_cache_get - Fetch a PMKSA cache entry
297 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
298 * @aa: Authenticator address or %NULL to match any
299 * @pmkid: PMKID or %NULL to match any
300 * Returns: Pointer to PMKSA cache entry or %NULL if no match was found
302 struct rsn_pmksa_cache_entry * pmksa_cache_get(struct rsn_pmksa_cache *pmksa,
303 const u8 *aa, const u8 *pmkid)
305 struct rsn_pmksa_cache_entry *entry = pmksa->pmksa;
307 if ((aa == NULL || os_memcmp(entry->aa, aa, ETH_ALEN) == 0) &&
309 os_memcmp(entry->pmkid, pmkid, PMKID_LEN) == 0))
317 static struct rsn_pmksa_cache_entry *
318 pmksa_cache_clone_entry(struct rsn_pmksa_cache *pmksa,
319 const struct rsn_pmksa_cache_entry *old_entry,
322 struct rsn_pmksa_cache_entry *new_entry;
324 new_entry = pmksa_cache_add(pmksa, old_entry->pmk, old_entry->pmk_len,
325 aa, pmksa->sm->own_addr,
326 old_entry->network_ctx, old_entry->akmp);
327 if (new_entry == NULL)
330 /* TODO: reorder entries based on expiration time? */
331 new_entry->expiration = old_entry->expiration;
332 new_entry->opportunistic = 1;
339 * pmksa_cache_get_opportunistic - Try to get an opportunistic PMKSA entry
340 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
341 * @network_ctx: Network configuration context
342 * @aa: Authenticator address for the new AP
343 * Returns: Pointer to a new PMKSA cache entry or %NULL if not available
345 * Try to create a new PMKSA cache entry opportunistically by guessing that the
346 * new AP is sharing the same PMK as another AP that has the same SSID and has
347 * already an entry in PMKSA cache.
349 struct rsn_pmksa_cache_entry *
350 pmksa_cache_get_opportunistic(struct rsn_pmksa_cache *pmksa, void *network_ctx,
353 struct rsn_pmksa_cache_entry *entry = pmksa->pmksa;
355 wpa_printf(MSG_DEBUG, "RSN: Consider " MACSTR " for OKC", MAC2STR(aa));
356 if (network_ctx == NULL)
359 if (entry->network_ctx == network_ctx) {
360 entry = pmksa_cache_clone_entry(pmksa, entry, aa);
362 wpa_printf(MSG_DEBUG, "RSN: added "
363 "opportunistic PMKSA cache entry "
364 "for " MACSTR, MAC2STR(aa));
375 * pmksa_cache_get_current - Get the current used PMKSA entry
376 * @sm: Pointer to WPA state machine data from wpa_sm_init()
377 * Returns: Pointer to the current PMKSA cache entry or %NULL if not available
379 struct rsn_pmksa_cache_entry * pmksa_cache_get_current(struct wpa_sm *sm)
383 return sm->cur_pmksa;
388 * pmksa_cache_clear_current - Clear the current PMKSA entry selection
389 * @sm: Pointer to WPA state machine data from wpa_sm_init()
391 void pmksa_cache_clear_current(struct wpa_sm *sm)
395 sm->cur_pmksa = NULL;
400 * pmksa_cache_set_current - Set the current PMKSA entry selection
401 * @sm: Pointer to WPA state machine data from wpa_sm_init()
402 * @pmkid: PMKID for selecting PMKSA or %NULL if not used
403 * @bssid: BSSID for PMKSA or %NULL if not used
404 * @network_ctx: Network configuration context
405 * @try_opportunistic: Whether to allow opportunistic PMKSA caching
406 * Returns: 0 if PMKSA was found or -1 if no matching entry was found
408 int pmksa_cache_set_current(struct wpa_sm *sm, const u8 *pmkid,
409 const u8 *bssid, void *network_ctx,
410 int try_opportunistic)
412 struct rsn_pmksa_cache *pmksa = sm->pmksa;
413 sm->cur_pmksa = NULL;
415 sm->cur_pmksa = pmksa_cache_get(pmksa, NULL, pmkid);
416 if (sm->cur_pmksa == NULL && bssid)
417 sm->cur_pmksa = pmksa_cache_get(pmksa, bssid, NULL);
418 if (sm->cur_pmksa == NULL && try_opportunistic && bssid)
419 sm->cur_pmksa = pmksa_cache_get_opportunistic(pmksa,
423 wpa_hexdump(MSG_DEBUG, "RSN: PMKID",
424 sm->cur_pmksa->pmkid, PMKID_LEN);
432 * pmksa_cache_list - Dump text list of entries in PMKSA cache
433 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
434 * @buf: Buffer for the list
435 * @len: Length of the buffer
436 * Returns: number of bytes written to buffer
438 * This function is used to generate a text format representation of the
439 * current PMKSA cache contents for the ctrl_iface PMKSA command.
441 int pmksa_cache_list(struct rsn_pmksa_cache *pmksa, char *buf, size_t len)
445 struct rsn_pmksa_cache_entry *entry;
449 ret = os_snprintf(pos, buf + len - pos,
450 "Index / AA / PMKID / expiration (in seconds) / "
452 if (ret < 0 || ret >= buf + len - pos)
456 entry = pmksa->pmksa;
459 ret = os_snprintf(pos, buf + len - pos, "%d " MACSTR " ",
460 i, MAC2STR(entry->aa));
461 if (ret < 0 || ret >= buf + len - pos)
464 pos += wpa_snprintf_hex(pos, buf + len - pos, entry->pmkid,
466 ret = os_snprintf(pos, buf + len - pos, " %d %d\n",
467 (int) (entry->expiration - now.sec),
468 entry->opportunistic);
469 if (ret < 0 || ret >= buf + len - pos)
479 * pmksa_cache_init - Initialize PMKSA cache
480 * @free_cb: Callback function to be called when a PMKSA cache entry is freed
481 * @ctx: Context pointer for free_cb function
482 * @sm: Pointer to WPA state machine data from wpa_sm_init()
483 * Returns: Pointer to PMKSA cache data or %NULL on failure
485 struct rsn_pmksa_cache *
486 pmksa_cache_init(void (*free_cb)(struct rsn_pmksa_cache_entry *entry,
487 void *ctx, int replace),
488 void *ctx, struct wpa_sm *sm)
490 struct rsn_pmksa_cache *pmksa;
492 pmksa = os_zalloc(sizeof(*pmksa));
494 pmksa->free_cb = free_cb;
502 #endif /* IEEE8021X_EAPOL and !CONFIG_NO_WPA2 */