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.
23 #include "eapol_supp/eapol_supp_sm.h"
24 #include "pmksa_cache.h"
26 #if defined(IEEE8021X_EAPOL) && !defined(CONFIG_NO_WPA2)
28 static const int pmksa_cache_max_entries = 32;
30 struct rsn_pmksa_cache {
31 struct rsn_pmksa_cache_entry *pmksa; /* PMKSA cache */
32 int pmksa_count; /* number of entries in PMKSA cache */
33 struct wpa_sm *sm; /* TODO: get rid of this reference(?) */
35 void (*free_cb)(struct rsn_pmksa_cache_entry *entry, void *ctx,
41 static void pmksa_cache_set_expiration(struct rsn_pmksa_cache *pmksa);
44 static void _pmksa_cache_free_entry(struct rsn_pmksa_cache_entry *entry)
50 static void pmksa_cache_free_entry(struct rsn_pmksa_cache *pmksa,
51 struct rsn_pmksa_cache_entry *entry,
55 pmksa->free_cb(entry, pmksa->ctx, replace);
56 _pmksa_cache_free_entry(entry);
60 static void pmksa_cache_expire(void *eloop_ctx, void *timeout_ctx)
62 struct rsn_pmksa_cache *pmksa = eloop_ctx;
66 while (pmksa->pmksa && pmksa->pmksa->expiration <= now.sec) {
67 struct rsn_pmksa_cache_entry *entry = pmksa->pmksa;
68 pmksa->pmksa = entry->next;
69 wpa_printf(MSG_DEBUG, "RSN: expired PMKSA cache entry for "
70 MACSTR, MAC2STR(entry->aa));
71 pmksa_cache_free_entry(pmksa, entry, 0);
74 pmksa_cache_set_expiration(pmksa);
78 static void pmksa_cache_reauth(void *eloop_ctx, void *timeout_ctx)
80 struct rsn_pmksa_cache *pmksa = eloop_ctx;
81 pmksa->sm->cur_pmksa = NULL;
82 eapol_sm_request_reauth(pmksa->sm->eapol);
86 static void pmksa_cache_set_expiration(struct rsn_pmksa_cache *pmksa)
89 struct rsn_pmksa_cache_entry *entry;
92 eloop_cancel_timeout(pmksa_cache_expire, pmksa, NULL);
93 eloop_cancel_timeout(pmksa_cache_reauth, pmksa, NULL);
94 if (pmksa->pmksa == NULL)
97 sec = pmksa->pmksa->expiration - now.sec;
100 eloop_register_timeout(sec + 1, 0, pmksa_cache_expire, pmksa, NULL);
102 entry = pmksa->sm->cur_pmksa ? pmksa->sm->cur_pmksa :
103 pmksa_cache_get(pmksa, pmksa->sm->bssid, NULL);
105 sec = pmksa->pmksa->reauth_time - now.sec;
108 eloop_register_timeout(sec, 0, pmksa_cache_reauth, pmksa,
115 * pmksa_cache_add - Add a PMKSA cache entry
116 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
117 * @pmk: The new pairwise master key
118 * @pmk_len: PMK length in bytes, usually PMK_LEN (32)
119 * @aa: Authenticator address
120 * @spa: Supplicant address
121 * @network_ctx: Network configuration context for this PMK
122 * @akmp: WPA_KEY_MGMT_* used in key derivation
123 * Returns: Pointer to the added PMKSA cache entry or %NULL on error
125 * This function create a PMKSA entry for a new PMK and adds it to the PMKSA
126 * cache. If an old entry is already in the cache for the same Authenticator,
127 * this entry will be replaced with the new entry. PMKID will be calculated
128 * based on the PMK and the driver interface is notified of the new PMKID.
130 struct rsn_pmksa_cache_entry *
131 pmksa_cache_add(struct rsn_pmksa_cache *pmksa, const u8 *pmk, size_t pmk_len,
132 const u8 *aa, const u8 *spa, void *network_ctx, int akmp)
134 struct rsn_pmksa_cache_entry *entry, *pos, *prev;
137 if (pmk_len > PMK_LEN)
140 entry = os_zalloc(sizeof(*entry));
143 os_memcpy(entry->pmk, pmk, pmk_len);
144 entry->pmk_len = pmk_len;
145 rsn_pmkid(pmk, pmk_len, aa, spa, entry->pmkid,
146 wpa_key_mgmt_sha256(akmp));
148 entry->expiration = now.sec + pmksa->sm->dot11RSNAConfigPMKLifetime;
149 entry->reauth_time = now.sec + pmksa->sm->dot11RSNAConfigPMKLifetime *
150 pmksa->sm->dot11RSNAConfigPMKReauthThreshold / 100;
152 os_memcpy(entry->aa, aa, ETH_ALEN);
153 entry->network_ctx = network_ctx;
155 /* Replace an old entry for the same Authenticator (if found) with the
160 if (os_memcmp(aa, pos->aa, ETH_ALEN) == 0) {
161 if (pos->pmk_len == pmk_len &&
162 os_memcmp(pos->pmk, pmk, pmk_len) == 0 &&
163 os_memcmp(pos->pmkid, entry->pmkid, PMKID_LEN) ==
165 wpa_printf(MSG_DEBUG, "WPA: reusing previous "
171 pmksa->pmksa = pos->next;
173 prev->next = pos->next;
174 if (pos == pmksa->sm->cur_pmksa) {
175 /* We are about to replace the current PMKSA
176 * cache entry. This happens when the PMKSA
177 * caching attempt fails, so we don't want to
178 * force pmksa_cache_free_entry() to disconnect
179 * at this point. Let's just make sure the old
180 * PMKSA cache entry will not be used in the
183 wpa_printf(MSG_DEBUG, "RSN: replacing current "
185 pmksa->sm->cur_pmksa = NULL;
187 wpa_printf(MSG_DEBUG, "RSN: Replace PMKSA entry for "
189 pmksa_cache_free_entry(pmksa, pos, 1);
196 if (pmksa->pmksa_count >= pmksa_cache_max_entries && pmksa->pmksa) {
197 /* Remove the oldest entry to make room for the new entry */
199 pmksa->pmksa = pos->next;
200 wpa_printf(MSG_DEBUG, "RSN: removed the oldest PMKSA cache "
201 "entry (for " MACSTR ") to make room for new one",
203 wpa_sm_remove_pmkid(pmksa->sm, pos->aa, pos->pmkid);
204 pmksa_cache_free_entry(pmksa, pos, 0);
207 /* Add the new entry; order by expiration time */
211 if (pos->expiration > entry->expiration)
217 entry->next = pmksa->pmksa;
218 pmksa->pmksa = entry;
219 pmksa_cache_set_expiration(pmksa);
221 entry->next = prev->next;
224 pmksa->pmksa_count++;
225 wpa_printf(MSG_DEBUG, "RSN: added PMKSA cache entry for " MACSTR,
227 wpa_sm_add_pmkid(pmksa->sm, entry->aa, entry->pmkid);
234 * pmksa_cache_deinit - Free all entries in PMKSA cache
235 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
237 void pmksa_cache_deinit(struct rsn_pmksa_cache *pmksa)
239 struct rsn_pmksa_cache_entry *entry, *prev;
244 entry = pmksa->pmksa;
251 pmksa_cache_set_expiration(pmksa);
257 * pmksa_cache_get - Fetch a PMKSA cache entry
258 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
259 * @aa: Authenticator address or %NULL to match any
260 * @pmkid: PMKID or %NULL to match any
261 * Returns: Pointer to PMKSA cache entry or %NULL if no match was found
263 struct rsn_pmksa_cache_entry * pmksa_cache_get(struct rsn_pmksa_cache *pmksa,
264 const u8 *aa, const u8 *pmkid)
266 struct rsn_pmksa_cache_entry *entry = pmksa->pmksa;
268 if ((aa == NULL || os_memcmp(entry->aa, aa, ETH_ALEN) == 0) &&
270 os_memcmp(entry->pmkid, pmkid, PMKID_LEN) == 0))
279 * pmksa_cache_notify_reconfig - Reconfiguration notification for PMKSA cache
280 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
282 * Clear references to old data structures when wpa_supplicant is reconfigured.
284 void pmksa_cache_notify_reconfig(struct rsn_pmksa_cache *pmksa)
286 struct rsn_pmksa_cache_entry *entry = pmksa->pmksa;
288 entry->network_ctx = NULL;
294 static struct rsn_pmksa_cache_entry *
295 pmksa_cache_clone_entry(struct rsn_pmksa_cache *pmksa,
296 const struct rsn_pmksa_cache_entry *old_entry,
299 struct rsn_pmksa_cache_entry *new_entry;
301 new_entry = pmksa_cache_add(pmksa, old_entry->pmk, old_entry->pmk_len,
302 aa, pmksa->sm->own_addr,
303 old_entry->network_ctx, old_entry->akmp);
304 if (new_entry == NULL)
307 /* TODO: reorder entries based on expiration time? */
308 new_entry->expiration = old_entry->expiration;
309 new_entry->opportunistic = 1;
316 * pmksa_cache_get_opportunistic - Try to get an opportunistic PMKSA entry
317 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
318 * @network_ctx: Network configuration context
319 * @aa: Authenticator address for the new AP
320 * Returns: Pointer to a new PMKSA cache entry or %NULL if not available
322 * Try to create a new PMKSA cache entry opportunistically by guessing that the
323 * new AP is sharing the same PMK as another AP that has the same SSID and has
324 * already an entry in PMKSA cache.
326 struct rsn_pmksa_cache_entry *
327 pmksa_cache_get_opportunistic(struct rsn_pmksa_cache *pmksa, void *network_ctx,
330 struct rsn_pmksa_cache_entry *entry = pmksa->pmksa;
332 if (network_ctx == NULL)
335 if (entry->network_ctx == network_ctx) {
336 entry = pmksa_cache_clone_entry(pmksa, entry, aa);
338 wpa_printf(MSG_DEBUG, "RSN: added "
339 "opportunistic PMKSA cache entry "
340 "for " MACSTR, MAC2STR(aa));
351 * pmksa_cache_get_current - Get the current used PMKSA entry
352 * @sm: Pointer to WPA state machine data from wpa_sm_init()
353 * Returns: Pointer to the current PMKSA cache entry or %NULL if not available
355 struct rsn_pmksa_cache_entry * pmksa_cache_get_current(struct wpa_sm *sm)
359 return sm->cur_pmksa;
364 * pmksa_cache_clear_current - Clear the current PMKSA entry selection
365 * @sm: Pointer to WPA state machine data from wpa_sm_init()
367 void pmksa_cache_clear_current(struct wpa_sm *sm)
371 sm->cur_pmksa = NULL;
376 * pmksa_cache_set_current - Set the current PMKSA entry selection
377 * @sm: Pointer to WPA state machine data from wpa_sm_init()
378 * @pmkid: PMKID for selecting PMKSA or %NULL if not used
379 * @bssid: BSSID for PMKSA or %NULL if not used
380 * @network_ctx: Network configuration context
381 * @try_opportunistic: Whether to allow opportunistic PMKSA caching
382 * Returns: 0 if PMKSA was found or -1 if no matching entry was found
384 int pmksa_cache_set_current(struct wpa_sm *sm, const u8 *pmkid,
385 const u8 *bssid, void *network_ctx,
386 int try_opportunistic)
388 struct rsn_pmksa_cache *pmksa = sm->pmksa;
389 sm->cur_pmksa = NULL;
391 sm->cur_pmksa = pmksa_cache_get(pmksa, NULL, pmkid);
392 if (sm->cur_pmksa == NULL && bssid)
393 sm->cur_pmksa = pmksa_cache_get(pmksa, bssid, NULL);
394 if (sm->cur_pmksa == NULL && try_opportunistic && bssid)
395 sm->cur_pmksa = pmksa_cache_get_opportunistic(pmksa,
399 wpa_hexdump(MSG_DEBUG, "RSN: PMKID",
400 sm->cur_pmksa->pmkid, PMKID_LEN);
408 * pmksa_cache_list - Dump text list of entries in PMKSA cache
409 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
410 * @buf: Buffer for the list
411 * @len: Length of the buffer
412 * Returns: number of bytes written to buffer
414 * This function is used to generate a text format representation of the
415 * current PMKSA cache contents for the ctrl_iface PMKSA command.
417 int pmksa_cache_list(struct rsn_pmksa_cache *pmksa, char *buf, size_t len)
421 struct rsn_pmksa_cache_entry *entry;
425 ret = os_snprintf(pos, buf + len - pos,
426 "Index / AA / PMKID / expiration (in seconds) / "
428 if (ret < 0 || ret >= buf + len - pos)
432 entry = pmksa->pmksa;
435 ret = os_snprintf(pos, buf + len - pos, "%d " MACSTR " ",
436 i, MAC2STR(entry->aa));
437 if (ret < 0 || ret >= buf + len - pos)
440 pos += wpa_snprintf_hex(pos, buf + len - pos, entry->pmkid,
442 ret = os_snprintf(pos, buf + len - pos, " %d %d\n",
443 (int) (entry->expiration - now.sec),
444 entry->opportunistic);
445 if (ret < 0 || ret >= buf + len - pos)
455 * pmksa_cache_init - Initialize PMKSA cache
456 * @free_cb: Callback function to be called when a PMKSA cache entry is freed
457 * @ctx: Context pointer for free_cb function
458 * @sm: Pointer to WPA state machine data from wpa_sm_init()
459 * Returns: Pointer to PMKSA cache data or %NULL on failure
461 struct rsn_pmksa_cache *
462 pmksa_cache_init(void (*free_cb)(struct rsn_pmksa_cache_entry *entry,
463 void *ctx, int replace),
464 void *ctx, struct wpa_sm *sm)
466 struct rsn_pmksa_cache *pmksa;
468 pmksa = os_zalloc(sizeof(*pmksa));
470 pmksa->free_cb = free_cb;
478 #endif /* IEEE8021X_EAPOL and !CONFIG_NO_WPA2 */