2 * WPA Supplicant - RSN PMKSA cache
3 * Copyright (c) 2004-2009, 2011-2015, Jouni Malinen <j@w1.fi>
5 * This software may be distributed under the terms of the BSD license.
6 * See README for more details.
13 #include "eapol_supp/eapol_supp_sm.h"
16 #include "pmksa_cache.h"
18 #if defined(IEEE8021X_EAPOL) && !defined(CONFIG_NO_WPA)
20 static const int pmksa_cache_max_entries = 32;
22 struct rsn_pmksa_cache {
23 struct rsn_pmksa_cache_entry *pmksa; /* PMKSA cache */
24 int pmksa_count; /* number of entries in PMKSA cache */
25 struct wpa_sm *sm; /* TODO: get rid of this reference(?) */
27 void (*free_cb)(struct rsn_pmksa_cache_entry *entry, void *ctx,
28 enum pmksa_free_reason reason);
33 static void pmksa_cache_set_expiration(struct rsn_pmksa_cache *pmksa);
36 static void _pmksa_cache_free_entry(struct rsn_pmksa_cache_entry *entry)
38 bin_clear_free(entry, sizeof(*entry));
42 static void pmksa_cache_free_entry(struct rsn_pmksa_cache *pmksa,
43 struct rsn_pmksa_cache_entry *entry,
44 enum pmksa_free_reason reason)
46 wpa_sm_remove_pmkid(pmksa->sm, entry->aa, entry->pmkid);
48 pmksa->free_cb(entry, pmksa->ctx, reason);
49 _pmksa_cache_free_entry(entry);
53 static void pmksa_cache_expire(void *eloop_ctx, void *timeout_ctx)
55 struct rsn_pmksa_cache *pmksa = eloop_ctx;
56 struct os_reltime now;
59 while (pmksa->pmksa && pmksa->pmksa->expiration <= now.sec) {
60 struct rsn_pmksa_cache_entry *entry = pmksa->pmksa;
61 pmksa->pmksa = entry->next;
62 wpa_printf(MSG_DEBUG, "RSN: expired PMKSA cache entry for "
63 MACSTR, MAC2STR(entry->aa));
64 pmksa_cache_free_entry(pmksa, entry, PMKSA_EXPIRE);
67 pmksa_cache_set_expiration(pmksa);
71 static void pmksa_cache_reauth(void *eloop_ctx, void *timeout_ctx)
73 struct rsn_pmksa_cache *pmksa = eloop_ctx;
74 pmksa->sm->cur_pmksa = NULL;
75 eapol_sm_request_reauth(pmksa->sm->eapol);
79 static void pmksa_cache_set_expiration(struct rsn_pmksa_cache *pmksa)
82 struct rsn_pmksa_cache_entry *entry;
83 struct os_reltime now;
85 eloop_cancel_timeout(pmksa_cache_expire, pmksa, NULL);
86 eloop_cancel_timeout(pmksa_cache_reauth, pmksa, NULL);
87 if (pmksa->pmksa == NULL)
90 sec = pmksa->pmksa->expiration - now.sec;
93 eloop_register_timeout(sec + 1, 0, pmksa_cache_expire, pmksa, NULL);
95 entry = pmksa->sm->cur_pmksa ? pmksa->sm->cur_pmksa :
96 pmksa_cache_get(pmksa, pmksa->sm->bssid, NULL, NULL);
98 sec = pmksa->pmksa->reauth_time - now.sec;
101 eloop_register_timeout(sec, 0, pmksa_cache_reauth, pmksa,
108 * pmksa_cache_add - Add a PMKSA cache entry
109 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
110 * @pmk: The new pairwise master key
111 * @pmk_len: PMK length in bytes, usually PMK_LEN (32)
112 * @pmkid: Calculated PMKID
113 * @kck: Key confirmation key or %NULL if not yet derived
114 * @kck_len: KCK length in bytes
115 * @aa: Authenticator address
116 * @spa: Supplicant address
117 * @network_ctx: Network configuration context for this PMK
118 * @akmp: WPA_KEY_MGMT_* used in key derivation
119 * Returns: Pointer to the added PMKSA cache entry or %NULL on error
121 * This function create a PMKSA entry for a new PMK and adds it to the PMKSA
122 * cache. If an old entry is already in the cache for the same Authenticator,
123 * this entry will be replaced with the new entry. PMKID will be calculated
124 * based on the PMK and the driver interface is notified of the new PMKID.
126 struct rsn_pmksa_cache_entry *
127 pmksa_cache_add(struct rsn_pmksa_cache *pmksa, const u8 *pmk, size_t pmk_len,
128 const u8 *pmkid, const u8 *kck, size_t kck_len,
129 const u8 *aa, const u8 *spa, void *network_ctx, int akmp)
131 struct rsn_pmksa_cache_entry *entry, *pos, *prev;
132 struct os_reltime now;
134 if (pmk_len > PMK_LEN_MAX)
137 if (wpa_key_mgmt_suite_b(akmp) && !kck)
140 entry = os_zalloc(sizeof(*entry));
143 os_memcpy(entry->pmk, pmk, pmk_len);
144 entry->pmk_len = pmk_len;
146 os_memcpy(entry->pmkid, pmkid, PMKID_LEN);
147 else if (akmp == WPA_KEY_MGMT_IEEE8021X_SUITE_B_192)
148 rsn_pmkid_suite_b_192(kck, kck_len, aa, spa, entry->pmkid);
149 else if (wpa_key_mgmt_suite_b(akmp))
150 rsn_pmkid_suite_b(kck, kck_len, aa, spa, entry->pmkid);
152 rsn_pmkid(pmk, pmk_len, aa, spa, entry->pmkid,
153 wpa_key_mgmt_sha256(akmp));
154 os_get_reltime(&now);
155 entry->expiration = now.sec + pmksa->sm->dot11RSNAConfigPMKLifetime;
156 entry->reauth_time = now.sec + pmksa->sm->dot11RSNAConfigPMKLifetime *
157 pmksa->sm->dot11RSNAConfigPMKReauthThreshold / 100;
159 os_memcpy(entry->aa, aa, ETH_ALEN);
160 entry->network_ctx = network_ctx;
162 /* Replace an old entry for the same Authenticator (if found) with the
167 if (os_memcmp(aa, pos->aa, ETH_ALEN) == 0) {
168 if (pos->pmk_len == pmk_len &&
169 os_memcmp_const(pos->pmk, pmk, pmk_len) == 0 &&
170 os_memcmp_const(pos->pmkid, entry->pmkid,
172 wpa_printf(MSG_DEBUG, "WPA: reusing previous "
178 pmksa->pmksa = pos->next;
180 prev->next = pos->next;
183 * If OKC is used, there may be other PMKSA cache
184 * entries based on the same PMK. These needs to be
185 * flushed so that a new entry can be created based on
186 * the new PMK. Only clear other entries if they have a
187 * matching PMK and this PMK has been used successfully
188 * with the current AP, i.e., if opportunistic flag has
189 * been cleared in wpa_supplicant_key_neg_complete().
191 wpa_printf(MSG_DEBUG, "RSN: Replace PMKSA entry for "
192 "the current AP and any PMKSA cache entry "
193 "that was based on the old PMK");
194 if (!pos->opportunistic)
195 pmksa_cache_flush(pmksa, network_ctx, pos->pmk,
197 pmksa_cache_free_entry(pmksa, pos, PMKSA_REPLACE);
204 if (pmksa->pmksa_count >= pmksa_cache_max_entries && pmksa->pmksa) {
205 /* Remove the oldest entry to make room for the new entry */
208 if (pos == pmksa->sm->cur_pmksa) {
210 * Never remove the current PMKSA cache entry, since
211 * it's in use, and removing it triggers a needless
215 pmksa->pmksa->next = pos ? pos->next : NULL;
217 pmksa->pmksa = pos->next;
220 wpa_printf(MSG_DEBUG, "RSN: removed the oldest idle "
221 "PMKSA cache entry (for " MACSTR ") to "
222 "make room for new one",
224 pmksa_cache_free_entry(pmksa, pos, PMKSA_FREE);
228 /* Add the new entry; order by expiration time */
232 if (pos->expiration > entry->expiration)
238 entry->next = pmksa->pmksa;
239 pmksa->pmksa = entry;
240 pmksa_cache_set_expiration(pmksa);
242 entry->next = prev->next;
245 pmksa->pmksa_count++;
246 wpa_printf(MSG_DEBUG, "RSN: Added PMKSA cache entry for " MACSTR
247 " network_ctx=%p", MAC2STR(entry->aa), network_ctx);
248 wpa_sm_add_pmkid(pmksa->sm, entry->aa, entry->pmkid);
255 * pmksa_cache_flush - Flush PMKSA cache entries for a specific network
256 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
257 * @network_ctx: Network configuration context or %NULL to flush all entries
258 * @pmk: PMK to match for or %NYLL to match all PMKs
259 * @pmk_len: PMK length
261 void pmksa_cache_flush(struct rsn_pmksa_cache *pmksa, void *network_ctx,
262 const u8 *pmk, size_t pmk_len)
264 struct rsn_pmksa_cache_entry *entry, *prev = NULL, *tmp;
267 entry = pmksa->pmksa;
269 if ((entry->network_ctx == network_ctx ||
270 network_ctx == NULL) &&
272 (pmk_len == entry->pmk_len &&
273 os_memcmp(pmk, entry->pmk, pmk_len) == 0))) {
274 wpa_printf(MSG_DEBUG, "RSN: Flush PMKSA cache entry "
275 "for " MACSTR, MAC2STR(entry->aa));
277 prev->next = entry->next;
279 pmksa->pmksa = entry->next;
282 pmksa_cache_free_entry(pmksa, tmp, PMKSA_FREE);
290 pmksa_cache_set_expiration(pmksa);
295 * pmksa_cache_deinit - Free all entries in PMKSA cache
296 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
298 void pmksa_cache_deinit(struct rsn_pmksa_cache *pmksa)
300 struct rsn_pmksa_cache_entry *entry, *prev;
305 entry = pmksa->pmksa;
312 pmksa_cache_set_expiration(pmksa);
318 * pmksa_cache_get - Fetch a PMKSA cache entry
319 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
320 * @aa: Authenticator address or %NULL to match any
321 * @pmkid: PMKID or %NULL to match any
322 * @network_ctx: Network context or %NULL to match any
323 * Returns: Pointer to PMKSA cache entry or %NULL if no match was found
325 struct rsn_pmksa_cache_entry * pmksa_cache_get(struct rsn_pmksa_cache *pmksa,
326 const u8 *aa, const u8 *pmkid,
327 const void *network_ctx)
329 struct rsn_pmksa_cache_entry *entry = pmksa->pmksa;
331 if ((aa == NULL || os_memcmp(entry->aa, aa, ETH_ALEN) == 0) &&
333 os_memcmp(entry->pmkid, pmkid, PMKID_LEN) == 0) &&
334 (network_ctx == NULL || network_ctx == entry->network_ctx))
342 static struct rsn_pmksa_cache_entry *
343 pmksa_cache_clone_entry(struct rsn_pmksa_cache *pmksa,
344 const struct rsn_pmksa_cache_entry *old_entry,
347 struct rsn_pmksa_cache_entry *new_entry;
349 new_entry = pmksa_cache_add(pmksa, old_entry->pmk, old_entry->pmk_len,
351 aa, pmksa->sm->own_addr,
352 old_entry->network_ctx, old_entry->akmp);
353 if (new_entry == NULL)
356 /* TODO: reorder entries based on expiration time? */
357 new_entry->expiration = old_entry->expiration;
358 new_entry->opportunistic = 1;
365 * pmksa_cache_get_opportunistic - Try to get an opportunistic PMKSA entry
366 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
367 * @network_ctx: Network configuration context
368 * @aa: Authenticator address for the new AP
369 * Returns: Pointer to a new PMKSA cache entry or %NULL if not available
371 * Try to create a new PMKSA cache entry opportunistically by guessing that the
372 * new AP is sharing the same PMK as another AP that has the same SSID and has
373 * already an entry in PMKSA cache.
375 struct rsn_pmksa_cache_entry *
376 pmksa_cache_get_opportunistic(struct rsn_pmksa_cache *pmksa, void *network_ctx,
379 struct rsn_pmksa_cache_entry *entry = pmksa->pmksa;
381 wpa_printf(MSG_DEBUG, "RSN: Consider " MACSTR " for OKC", MAC2STR(aa));
382 if (network_ctx == NULL)
385 if (entry->network_ctx == network_ctx) {
386 entry = pmksa_cache_clone_entry(pmksa, entry, aa);
388 wpa_printf(MSG_DEBUG, "RSN: added "
389 "opportunistic PMKSA cache entry "
390 "for " MACSTR, MAC2STR(aa));
401 * pmksa_cache_get_current - Get the current used PMKSA entry
402 * @sm: Pointer to WPA state machine data from wpa_sm_init()
403 * Returns: Pointer to the current PMKSA cache entry or %NULL if not available
405 struct rsn_pmksa_cache_entry * pmksa_cache_get_current(struct wpa_sm *sm)
409 return sm->cur_pmksa;
414 * pmksa_cache_clear_current - Clear the current PMKSA entry selection
415 * @sm: Pointer to WPA state machine data from wpa_sm_init()
417 void pmksa_cache_clear_current(struct wpa_sm *sm)
421 sm->cur_pmksa = NULL;
426 * pmksa_cache_set_current - Set the current PMKSA entry selection
427 * @sm: Pointer to WPA state machine data from wpa_sm_init()
428 * @pmkid: PMKID for selecting PMKSA or %NULL if not used
429 * @bssid: BSSID for PMKSA or %NULL if not used
430 * @network_ctx: Network configuration context
431 * @try_opportunistic: Whether to allow opportunistic PMKSA caching
432 * Returns: 0 if PMKSA was found or -1 if no matching entry was found
434 int pmksa_cache_set_current(struct wpa_sm *sm, const u8 *pmkid,
435 const u8 *bssid, void *network_ctx,
436 int try_opportunistic)
438 struct rsn_pmksa_cache *pmksa = sm->pmksa;
439 wpa_printf(MSG_DEBUG, "RSN: PMKSA cache search - network_ctx=%p "
440 "try_opportunistic=%d", network_ctx, try_opportunistic);
442 wpa_hexdump(MSG_DEBUG, "RSN: Search for PMKID",
445 wpa_printf(MSG_DEBUG, "RSN: Search for BSSID " MACSTR,
448 sm->cur_pmksa = NULL;
450 sm->cur_pmksa = pmksa_cache_get(pmksa, NULL, pmkid,
452 if (sm->cur_pmksa == NULL && bssid)
453 sm->cur_pmksa = pmksa_cache_get(pmksa, bssid, NULL,
455 if (sm->cur_pmksa == NULL && try_opportunistic && bssid)
456 sm->cur_pmksa = pmksa_cache_get_opportunistic(pmksa,
460 wpa_hexdump(MSG_DEBUG, "RSN: PMKSA cache entry found - PMKID",
461 sm->cur_pmksa->pmkid, PMKID_LEN);
464 wpa_printf(MSG_DEBUG, "RSN: No PMKSA cache entry found");
470 * pmksa_cache_list - Dump text list of entries in PMKSA cache
471 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
472 * @buf: Buffer for the list
473 * @len: Length of the buffer
474 * Returns: number of bytes written to buffer
476 * This function is used to generate a text format representation of the
477 * current PMKSA cache contents for the ctrl_iface PMKSA command.
479 int pmksa_cache_list(struct rsn_pmksa_cache *pmksa, char *buf, size_t len)
483 struct rsn_pmksa_cache_entry *entry;
484 struct os_reltime now;
486 os_get_reltime(&now);
487 ret = os_snprintf(pos, buf + len - pos,
488 "Index / AA / PMKID / expiration (in seconds) / "
490 if (os_snprintf_error(buf + len - pos, ret))
494 entry = pmksa->pmksa;
497 ret = os_snprintf(pos, buf + len - pos, "%d " MACSTR " ",
498 i, MAC2STR(entry->aa));
499 if (os_snprintf_error(buf + len - pos, ret))
502 pos += wpa_snprintf_hex(pos, buf + len - pos, entry->pmkid,
504 ret = os_snprintf(pos, buf + len - pos, " %d %d\n",
505 (int) (entry->expiration - now.sec),
506 entry->opportunistic);
507 if (os_snprintf_error(buf + len - pos, ret))
517 * pmksa_cache_init - Initialize PMKSA cache
518 * @free_cb: Callback function to be called when a PMKSA cache entry is freed
519 * @ctx: Context pointer for free_cb function
520 * @sm: Pointer to WPA state machine data from wpa_sm_init()
521 * Returns: Pointer to PMKSA cache data or %NULL on failure
523 struct rsn_pmksa_cache *
524 pmksa_cache_init(void (*free_cb)(struct rsn_pmksa_cache_entry *entry,
525 void *ctx, enum pmksa_free_reason reason),
526 void *ctx, struct wpa_sm *sm)
528 struct rsn_pmksa_cache *pmksa;
530 pmksa = os_zalloc(sizeof(*pmksa));
532 pmksa->free_cb = free_cb;
540 #endif /* IEEE8021X_EAPOL */