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);
195 if (pmksa->pmksa_count >= pmksa_cache_max_entries && pmksa->pmksa) {
196 /* Remove the oldest entry to make room for the new entry */
198 pmksa->pmksa = pos->next;
199 wpa_printf(MSG_DEBUG, "RSN: removed the oldest PMKSA cache "
200 "entry (for " MACSTR ") to make room for new one",
202 wpa_sm_remove_pmkid(pmksa->sm, pos->aa, pos->pmkid);
203 pmksa_cache_free_entry(pmksa, pos, 0);
206 /* Add the new entry; order by expiration time */
210 if (pos->expiration > entry->expiration)
216 entry->next = pmksa->pmksa;
217 pmksa->pmksa = entry;
218 pmksa_cache_set_expiration(pmksa);
220 entry->next = prev->next;
223 pmksa->pmksa_count++;
224 wpa_printf(MSG_DEBUG, "RSN: added PMKSA cache entry for " MACSTR,
226 wpa_sm_add_pmkid(pmksa->sm, entry->aa, entry->pmkid);
233 * pmksa_cache_deinit - Free all entries in PMKSA cache
234 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
236 void pmksa_cache_deinit(struct rsn_pmksa_cache *pmksa)
238 struct rsn_pmksa_cache_entry *entry, *prev;
243 entry = pmksa->pmksa;
250 pmksa_cache_set_expiration(pmksa);
256 * pmksa_cache_get - Fetch a PMKSA cache entry
257 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
258 * @aa: Authenticator address or %NULL to match any
259 * @pmkid: PMKID or %NULL to match any
260 * Returns: Pointer to PMKSA cache entry or %NULL if no match was found
262 struct rsn_pmksa_cache_entry * pmksa_cache_get(struct rsn_pmksa_cache *pmksa,
263 const u8 *aa, const u8 *pmkid)
265 struct rsn_pmksa_cache_entry *entry = pmksa->pmksa;
267 if ((aa == NULL || os_memcmp(entry->aa, aa, ETH_ALEN) == 0) &&
269 os_memcmp(entry->pmkid, pmkid, PMKID_LEN) == 0))
278 * pmksa_cache_notify_reconfig - Reconfiguration notification for PMKSA cache
279 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
281 * Clear references to old data structures when wpa_supplicant is reconfigured.
283 void pmksa_cache_notify_reconfig(struct rsn_pmksa_cache *pmksa)
285 struct rsn_pmksa_cache_entry *entry = pmksa->pmksa;
287 entry->network_ctx = NULL;
293 static struct rsn_pmksa_cache_entry *
294 pmksa_cache_clone_entry(struct rsn_pmksa_cache *pmksa,
295 const struct rsn_pmksa_cache_entry *old_entry,
298 struct rsn_pmksa_cache_entry *new_entry;
300 new_entry = pmksa_cache_add(pmksa, old_entry->pmk, old_entry->pmk_len,
301 aa, pmksa->sm->own_addr,
302 old_entry->network_ctx, old_entry->akmp);
303 if (new_entry == NULL)
306 /* TODO: reorder entries based on expiration time? */
307 new_entry->expiration = old_entry->expiration;
308 new_entry->opportunistic = 1;
315 * pmksa_cache_get_opportunistic - Try to get an opportunistic PMKSA entry
316 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
317 * @network_ctx: Network configuration context
318 * @aa: Authenticator address for the new AP
319 * Returns: Pointer to a new PMKSA cache entry or %NULL if not available
321 * Try to create a new PMKSA cache entry opportunistically by guessing that the
322 * new AP is sharing the same PMK as another AP that has the same SSID and has
323 * already an entry in PMKSA cache.
325 struct rsn_pmksa_cache_entry *
326 pmksa_cache_get_opportunistic(struct rsn_pmksa_cache *pmksa, void *network_ctx,
329 struct rsn_pmksa_cache_entry *entry = pmksa->pmksa;
331 if (network_ctx == NULL)
334 if (entry->network_ctx == network_ctx) {
335 entry = pmksa_cache_clone_entry(pmksa, entry, aa);
337 wpa_printf(MSG_DEBUG, "RSN: added "
338 "opportunistic PMKSA cache entry "
339 "for " MACSTR, MAC2STR(aa));
350 * pmksa_cache_get_current - Get the current used PMKSA entry
351 * @sm: Pointer to WPA state machine data from wpa_sm_init()
352 * Returns: Pointer to the current PMKSA cache entry or %NULL if not available
354 struct rsn_pmksa_cache_entry * pmksa_cache_get_current(struct wpa_sm *sm)
358 return sm->cur_pmksa;
363 * pmksa_cache_clear_current - Clear the current PMKSA entry selection
364 * @sm: Pointer to WPA state machine data from wpa_sm_init()
366 void pmksa_cache_clear_current(struct wpa_sm *sm)
370 sm->cur_pmksa = NULL;
375 * pmksa_cache_set_current - Set the current PMKSA entry selection
376 * @sm: Pointer to WPA state machine data from wpa_sm_init()
377 * @pmkid: PMKID for selecting PMKSA or %NULL if not used
378 * @bssid: BSSID for PMKSA or %NULL if not used
379 * @network_ctx: Network configuration context
380 * @try_opportunistic: Whether to allow opportunistic PMKSA caching
381 * Returns: 0 if PMKSA was found or -1 if no matching entry was found
383 int pmksa_cache_set_current(struct wpa_sm *sm, const u8 *pmkid,
384 const u8 *bssid, void *network_ctx,
385 int try_opportunistic)
387 struct rsn_pmksa_cache *pmksa = sm->pmksa;
388 sm->cur_pmksa = NULL;
390 sm->cur_pmksa = pmksa_cache_get(pmksa, NULL, pmkid);
391 if (sm->cur_pmksa == NULL && bssid)
392 sm->cur_pmksa = pmksa_cache_get(pmksa, bssid, NULL);
393 if (sm->cur_pmksa == NULL && try_opportunistic && bssid)
394 sm->cur_pmksa = pmksa_cache_get_opportunistic(pmksa,
398 wpa_hexdump(MSG_DEBUG, "RSN: PMKID",
399 sm->cur_pmksa->pmkid, PMKID_LEN);
407 * pmksa_cache_list - Dump text list of entries in PMKSA cache
408 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
409 * @buf: Buffer for the list
410 * @len: Length of the buffer
411 * Returns: number of bytes written to buffer
413 * This function is used to generate a text format representation of the
414 * current PMKSA cache contents for the ctrl_iface PMKSA command.
416 int pmksa_cache_list(struct rsn_pmksa_cache *pmksa, char *buf, size_t len)
420 struct rsn_pmksa_cache_entry *entry;
424 ret = os_snprintf(pos, buf + len - pos,
425 "Index / AA / PMKID / expiration (in seconds) / "
427 if (ret < 0 || ret >= buf + len - pos)
431 entry = pmksa->pmksa;
434 ret = os_snprintf(pos, buf + len - pos, "%d " MACSTR " ",
435 i, MAC2STR(entry->aa));
436 if (ret < 0 || ret >= buf + len - pos)
439 pos += wpa_snprintf_hex(pos, buf + len - pos, entry->pmkid,
441 ret = os_snprintf(pos, buf + len - pos, " %d %d\n",
442 (int) (entry->expiration - now.sec),
443 entry->opportunistic);
444 if (ret < 0 || ret >= buf + len - pos)
454 * pmksa_cache_init - Initialize PMKSA cache
455 * @free_cb: Callback function to be called when a PMKSA cache entry is freed
456 * @ctx: Context pointer for free_cb function
457 * @sm: Pointer to WPA state machine data from wpa_sm_init()
458 * Returns: Pointer to PMKSA cache data or %NULL on failure
460 struct rsn_pmksa_cache *
461 pmksa_cache_init(void (*free_cb)(struct rsn_pmksa_cache_entry *entry,
462 void *ctx, int replace),
463 void *ctx, struct wpa_sm *sm)
465 struct rsn_pmksa_cache *pmksa;
467 pmksa = os_zalloc(sizeof(*pmksa));
469 pmksa->free_cb = free_cb;
477 #endif /* IEEE8021X_EAPOL and !CONFIG_NO_WPA2 */