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 pmksa_cache_free_entry(pmksa, entry, 0);
72 pmksa_cache_set_expiration(pmksa);
76 static void pmksa_cache_reauth(void *eloop_ctx, void *timeout_ctx)
78 struct rsn_pmksa_cache *pmksa = eloop_ctx;
79 pmksa->sm->cur_pmksa = NULL;
80 eapol_sm_request_reauth(pmksa->sm->eapol);
84 static void pmksa_cache_set_expiration(struct rsn_pmksa_cache *pmksa)
87 struct rsn_pmksa_cache_entry *entry;
90 eloop_cancel_timeout(pmksa_cache_expire, pmksa, NULL);
91 eloop_cancel_timeout(pmksa_cache_reauth, pmksa, NULL);
92 if (pmksa->pmksa == NULL)
95 sec = pmksa->pmksa->expiration - now.sec;
98 eloop_register_timeout(sec + 1, 0, pmksa_cache_expire, pmksa, NULL);
100 entry = pmksa->sm->cur_pmksa ? pmksa->sm->cur_pmksa :
101 pmksa_cache_get(pmksa, pmksa->sm->bssid, NULL);
103 sec = pmksa->pmksa->reauth_time - now.sec;
106 eloop_register_timeout(sec, 0, pmksa_cache_reauth, pmksa,
113 * pmksa_cache_add - Add a PMKSA cache entry
114 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
115 * @pmk: The new pairwise master key
116 * @pmk_len: PMK length in bytes, usually PMK_LEN (32)
117 * @aa: Authenticator address
118 * @spa: Supplicant address
119 * @network_ctx: Network configuration context for this PMK
120 * @akmp: WPA_KEY_MGMT_* used in key derivation
121 * Returns: Pointer to the added PMKSA cache entry or %NULL on error
123 * This function create a PMKSA entry for a new PMK and adds it to the PMKSA
124 * cache. If an old entry is already in the cache for the same Authenticator,
125 * this entry will be replaced with the new entry. PMKID will be calculated
126 * based on the PMK and the driver interface is notified of the new PMKID.
128 struct rsn_pmksa_cache_entry *
129 pmksa_cache_add(struct rsn_pmksa_cache *pmksa, const u8 *pmk, size_t pmk_len,
130 const u8 *aa, const u8 *spa, void *network_ctx, int akmp)
132 struct rsn_pmksa_cache_entry *entry, *pos, *prev;
135 if (pmk_len > PMK_LEN)
138 entry = os_zalloc(sizeof(*entry));
141 os_memcpy(entry->pmk, pmk, pmk_len);
142 entry->pmk_len = pmk_len;
143 rsn_pmkid(pmk, pmk_len, aa, spa, entry->pmkid,
144 wpa_key_mgmt_sha256(akmp));
146 entry->expiration = now.sec + pmksa->sm->dot11RSNAConfigPMKLifetime;
147 entry->reauth_time = now.sec + pmksa->sm->dot11RSNAConfigPMKLifetime *
148 pmksa->sm->dot11RSNAConfigPMKReauthThreshold / 100;
150 os_memcpy(entry->aa, aa, ETH_ALEN);
151 entry->network_ctx = network_ctx;
153 /* Replace an old entry for the same Authenticator (if found) with the
158 if (os_memcmp(aa, pos->aa, ETH_ALEN) == 0) {
159 if (pos->pmk_len == pmk_len &&
160 os_memcmp(pos->pmk, pmk, pmk_len) == 0 &&
161 os_memcmp(pos->pmkid, entry->pmkid, PMKID_LEN) ==
163 wpa_printf(MSG_DEBUG, "WPA: reusing previous "
169 pmksa->pmksa = pos->next;
171 prev->next = pos->next;
172 if (pos == pmksa->sm->cur_pmksa) {
173 /* We are about to replace the current PMKSA
174 * cache entry. This happens when the PMKSA
175 * caching attempt fails, so we don't want to
176 * force pmksa_cache_free_entry() to disconnect
177 * at this point. Let's just make sure the old
178 * PMKSA cache entry will not be used in the
181 wpa_printf(MSG_DEBUG, "RSN: replacing current "
183 pmksa->sm->cur_pmksa = NULL;
185 wpa_printf(MSG_DEBUG, "RSN: Replace PMKSA entry for "
187 pmksa_cache_free_entry(pmksa, pos, 1);
194 if (pmksa->pmksa_count >= pmksa_cache_max_entries && pmksa->pmksa) {
195 /* Remove the oldest entry to make room for the new entry */
197 pmksa->pmksa = pos->next;
198 wpa_printf(MSG_DEBUG, "RSN: removed the oldest PMKSA cache "
199 "entry (for " MACSTR ") to make room for new one",
201 wpa_sm_remove_pmkid(pmksa->sm, pos->aa, pos->pmkid);
202 pmksa_cache_free_entry(pmksa, pos, 0);
205 /* Add the new entry; order by expiration time */
209 if (pos->expiration > entry->expiration)
215 entry->next = pmksa->pmksa;
216 pmksa->pmksa = entry;
217 pmksa_cache_set_expiration(pmksa);
219 entry->next = prev->next;
222 pmksa->pmksa_count++;
223 wpa_printf(MSG_DEBUG, "RSN: added PMKSA cache entry for " MACSTR,
225 wpa_sm_add_pmkid(pmksa->sm, entry->aa, entry->pmkid);
232 * pmksa_cache_deinit - Free all entries in PMKSA cache
233 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
235 void pmksa_cache_deinit(struct rsn_pmksa_cache *pmksa)
237 struct rsn_pmksa_cache_entry *entry, *prev;
242 entry = pmksa->pmksa;
249 pmksa_cache_set_expiration(pmksa);
255 * pmksa_cache_get - Fetch a PMKSA cache entry
256 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
257 * @aa: Authenticator address or %NULL to match any
258 * @pmkid: PMKID or %NULL to match any
259 * Returns: Pointer to PMKSA cache entry or %NULL if no match was found
261 struct rsn_pmksa_cache_entry * pmksa_cache_get(struct rsn_pmksa_cache *pmksa,
262 const u8 *aa, const u8 *pmkid)
264 struct rsn_pmksa_cache_entry *entry = pmksa->pmksa;
266 if ((aa == NULL || os_memcmp(entry->aa, aa, ETH_ALEN) == 0) &&
268 os_memcmp(entry->pmkid, pmkid, PMKID_LEN) == 0))
277 * pmksa_cache_notify_reconfig - Reconfiguration notification for PMKSA cache
278 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
280 * Clear references to old data structures when wpa_supplicant is reconfigured.
282 void pmksa_cache_notify_reconfig(struct rsn_pmksa_cache *pmksa)
284 struct rsn_pmksa_cache_entry *entry = pmksa->pmksa;
286 entry->network_ctx = NULL;
292 static struct rsn_pmksa_cache_entry *
293 pmksa_cache_clone_entry(struct rsn_pmksa_cache *pmksa,
294 const struct rsn_pmksa_cache_entry *old_entry,
297 struct rsn_pmksa_cache_entry *new_entry;
299 new_entry = pmksa_cache_add(pmksa, old_entry->pmk, old_entry->pmk_len,
300 aa, pmksa->sm->own_addr,
301 old_entry->network_ctx, old_entry->akmp);
302 if (new_entry == NULL)
305 /* TODO: reorder entries based on expiration time? */
306 new_entry->expiration = old_entry->expiration;
307 new_entry->opportunistic = 1;
314 * pmksa_cache_get_opportunistic - Try to get an opportunistic PMKSA entry
315 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
316 * @network_ctx: Network configuration context
317 * @aa: Authenticator address for the new AP
318 * Returns: Pointer to a new PMKSA cache entry or %NULL if not available
320 * Try to create a new PMKSA cache entry opportunistically by guessing that the
321 * new AP is sharing the same PMK as another AP that has the same SSID and has
322 * already an entry in PMKSA cache.
324 struct rsn_pmksa_cache_entry *
325 pmksa_cache_get_opportunistic(struct rsn_pmksa_cache *pmksa, void *network_ctx,
328 struct rsn_pmksa_cache_entry *entry = pmksa->pmksa;
330 if (network_ctx == NULL)
333 if (entry->network_ctx == network_ctx) {
334 entry = pmksa_cache_clone_entry(pmksa, entry, aa);
336 wpa_printf(MSG_DEBUG, "RSN: added "
337 "opportunistic PMKSA cache entry "
338 "for " MACSTR, MAC2STR(aa));
349 * pmksa_cache_get_current - Get the current used PMKSA entry
350 * @sm: Pointer to WPA state machine data from wpa_sm_init()
351 * Returns: Pointer to the current PMKSA cache entry or %NULL if not available
353 struct rsn_pmksa_cache_entry * pmksa_cache_get_current(struct wpa_sm *sm)
357 return sm->cur_pmksa;
362 * pmksa_cache_clear_current - Clear the current PMKSA entry selection
363 * @sm: Pointer to WPA state machine data from wpa_sm_init()
365 void pmksa_cache_clear_current(struct wpa_sm *sm)
369 sm->cur_pmksa = NULL;
374 * pmksa_cache_set_current - Set the current PMKSA entry selection
375 * @sm: Pointer to WPA state machine data from wpa_sm_init()
376 * @pmkid: PMKID for selecting PMKSA or %NULL if not used
377 * @bssid: BSSID for PMKSA or %NULL if not used
378 * @network_ctx: Network configuration context
379 * @try_opportunistic: Whether to allow opportunistic PMKSA caching
380 * Returns: 0 if PMKSA was found or -1 if no matching entry was found
382 int pmksa_cache_set_current(struct wpa_sm *sm, const u8 *pmkid,
383 const u8 *bssid, void *network_ctx,
384 int try_opportunistic)
386 struct rsn_pmksa_cache *pmksa = sm->pmksa;
387 sm->cur_pmksa = NULL;
389 sm->cur_pmksa = pmksa_cache_get(pmksa, NULL, pmkid);
390 if (sm->cur_pmksa == NULL && bssid)
391 sm->cur_pmksa = pmksa_cache_get(pmksa, bssid, NULL);
392 if (sm->cur_pmksa == NULL && try_opportunistic && bssid)
393 sm->cur_pmksa = pmksa_cache_get_opportunistic(pmksa,
397 wpa_hexdump(MSG_DEBUG, "RSN: PMKID",
398 sm->cur_pmksa->pmkid, PMKID_LEN);
406 * pmksa_cache_list - Dump text list of entries in PMKSA cache
407 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
408 * @buf: Buffer for the list
409 * @len: Length of the buffer
410 * Returns: number of bytes written to buffer
412 * This function is used to generate a text format representation of the
413 * current PMKSA cache contents for the ctrl_iface PMKSA command.
415 int pmksa_cache_list(struct rsn_pmksa_cache *pmksa, char *buf, size_t len)
419 struct rsn_pmksa_cache_entry *entry;
423 ret = os_snprintf(pos, buf + len - pos,
424 "Index / AA / PMKID / expiration (in seconds) / "
426 if (ret < 0 || ret >= buf + len - pos)
430 entry = pmksa->pmksa;
433 ret = os_snprintf(pos, buf + len - pos, "%d " MACSTR " ",
434 i, MAC2STR(entry->aa));
435 if (ret < 0 || ret >= buf + len - pos)
438 pos += wpa_snprintf_hex(pos, buf + len - pos, entry->pmkid,
440 ret = os_snprintf(pos, buf + len - pos, " %d %d\n",
441 (int) (entry->expiration - now.sec),
442 entry->opportunistic);
443 if (ret < 0 || ret >= buf + len - pos)
453 * pmksa_cache_init - Initialize PMKSA cache
454 * @free_cb: Callback function to be called when a PMKSA cache entry is freed
455 * @ctx: Context pointer for free_cb function
456 * @sm: Pointer to WPA state machine data from wpa_sm_init()
457 * Returns: Pointer to PMKSA cache data or %NULL on failure
459 struct rsn_pmksa_cache *
460 pmksa_cache_init(void (*free_cb)(struct rsn_pmksa_cache_entry *entry,
461 void *ctx, int replace),
462 void *ctx, struct wpa_sm *sm)
464 struct rsn_pmksa_cache *pmksa;
466 pmksa = os_zalloc(sizeof(*pmksa));
468 pmksa->free_cb = free_cb;
476 #endif /* IEEE8021X_EAPOL and !CONFIG_NO_WPA2 */