2 * hostapd - PMKSA cache for IEEE 802.11i RSN
3 * Copyright (c) 2004-2006, 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 "ieee802_1x.h"
25 #include "pmksa_cache.h"
28 static const int pmksa_cache_max_entries = 1024;
29 static const int dot11RSNAConfigPMKLifetime = 43200;
31 struct rsn_pmksa_cache {
32 #define PMKID_HASH_SIZE 128
33 #define PMKID_HASH(pmkid) (unsigned int) ((pmkid)[0] & 0x7f)
34 struct rsn_pmksa_cache_entry *pmkid[PMKID_HASH_SIZE];
35 struct rsn_pmksa_cache_entry *pmksa;
38 void (*free_cb)(struct rsn_pmksa_cache_entry *entry, void *ctx);
44 * rsn_pmkid - Calculate PMK identifier
45 * @pmk: Pairwise master key
46 * @pmk_len: Length of pmk in bytes
47 * @aa: Authenticator address
48 * @spa: Supplicant address
50 * IEEE Std 802.11i-2004 - 8.5.1.2 Pairwise key hierarchy
51 * PMKID = HMAC-SHA1-128(PMK, "PMK Name" || AA || SPA)
53 void rsn_pmkid(const u8 *pmk, size_t pmk_len, const u8 *aa, const u8 *spa,
56 char *title = "PMK Name";
58 const size_t len[3] = { 8, ETH_ALEN, ETH_ALEN };
59 unsigned char hash[SHA1_MAC_LEN];
61 addr[0] = (u8 *) title;
65 hmac_sha1_vector(pmk, pmk_len, 3, addr, len, hash);
66 os_memcpy(pmkid, hash, PMKID_LEN);
70 static void pmksa_cache_set_expiration(struct rsn_pmksa_cache *pmksa);
73 static void _pmksa_cache_free_entry(struct rsn_pmksa_cache_entry *entry)
77 os_free(entry->identity);
78 ieee802_1x_free_radius_class(&entry->radius_class);
83 static void pmksa_cache_free_entry(struct rsn_pmksa_cache *pmksa,
84 struct rsn_pmksa_cache_entry *entry)
86 struct rsn_pmksa_cache_entry *pos, *prev;
89 pmksa->free_cb(entry, pmksa->ctx);
90 pos = pmksa->pmkid[PMKID_HASH(entry->pmkid)];
95 prev->hnext = pos->hnext;
97 pmksa->pmkid[PMKID_HASH(entry->pmkid)] =
111 prev->next = pos->next;
113 pmksa->pmksa = pos->next;
119 _pmksa_cache_free_entry(entry);
123 static void pmksa_cache_expire(void *eloop_ctx, void *timeout_ctx)
125 struct rsn_pmksa_cache *pmksa = eloop_ctx;
129 while (pmksa->pmksa && pmksa->pmksa->expiration <= now.sec) {
130 struct rsn_pmksa_cache_entry *entry = pmksa->pmksa;
131 pmksa->pmksa = entry->next;
132 wpa_printf(MSG_DEBUG, "RSN: expired PMKSA cache entry for "
133 MACSTR, MAC2STR(entry->spa));
134 pmksa_cache_free_entry(pmksa, entry);
137 pmksa_cache_set_expiration(pmksa);
141 static void pmksa_cache_set_expiration(struct rsn_pmksa_cache *pmksa)
146 eloop_cancel_timeout(pmksa_cache_expire, pmksa, NULL);
147 if (pmksa->pmksa == NULL)
150 sec = pmksa->pmksa->expiration - now.sec;
153 eloop_register_timeout(sec + 1, 0, pmksa_cache_expire, pmksa, NULL);
157 static void pmksa_cache_from_eapol_data(struct rsn_pmksa_cache_entry *entry,
158 struct eapol_state_machine *eapol)
163 if (eapol->identity) {
164 entry->identity = os_malloc(eapol->identity_len);
165 if (entry->identity) {
166 entry->identity_len = eapol->identity_len;
167 os_memcpy(entry->identity, eapol->identity,
168 eapol->identity_len);
172 ieee802_1x_copy_radius_class(&entry->radius_class,
173 &eapol->radius_class);
175 entry->eap_type_authsrv = eapol->eap_type_authsrv;
176 entry->vlan_id = eapol->sta->vlan_id;
180 void pmksa_cache_to_eapol_data(struct rsn_pmksa_cache_entry *entry,
181 struct eapol_state_machine *eapol)
183 if (entry == NULL || eapol == NULL)
186 if (entry->identity) {
187 os_free(eapol->identity);
188 eapol->identity = os_malloc(entry->identity_len);
189 if (eapol->identity) {
190 eapol->identity_len = entry->identity_len;
191 os_memcpy(eapol->identity, entry->identity,
192 entry->identity_len);
194 wpa_hexdump_ascii(MSG_DEBUG, "STA identity from PMKSA",
195 eapol->identity, eapol->identity_len);
198 ieee802_1x_free_radius_class(&eapol->radius_class);
199 ieee802_1x_copy_radius_class(&eapol->radius_class,
200 &entry->radius_class);
201 if (eapol->radius_class.attr) {
202 wpa_printf(MSG_DEBUG, "Copied %lu Class attribute(s) from "
203 "PMKSA", (unsigned long) eapol->radius_class.count);
206 eapol->eap_type_authsrv = entry->eap_type_authsrv;
207 eapol->sta->vlan_id = entry->vlan_id;
212 * pmksa_cache_add - Add a PMKSA cache entry
213 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
214 * @pmk: The new pairwise master key
215 * @pmk_len: PMK length in bytes, usually PMK_LEN (32)
216 * @aa: Authenticator address
217 * @spa: Supplicant address
218 * @session_timeout: Session timeout
219 * @eapol: Pointer to EAPOL state machine data
220 * Returns: Pointer to the added PMKSA cache entry or %NULL on error
222 * This function create a PMKSA entry for a new PMK and adds it to the PMKSA
223 * cache. If an old entry is already in the cache for the same Supplicant,
224 * this entry will be replaced with the new entry. PMKID will be calculated
227 struct rsn_pmksa_cache_entry *
228 pmksa_cache_add(struct rsn_pmksa_cache *pmksa, const u8 *pmk, size_t pmk_len,
229 const u8 *aa, const u8 *spa, int session_timeout,
230 struct eapol_state_machine *eapol)
232 struct rsn_pmksa_cache_entry *entry, *pos, *prev;
235 if (pmk_len > PMK_LEN)
238 entry = os_zalloc(sizeof(*entry));
241 os_memcpy(entry->pmk, pmk, pmk_len);
242 entry->pmk_len = pmk_len;
243 rsn_pmkid(pmk, pmk_len, aa, spa, entry->pmkid);
245 entry->expiration = now.sec;
246 if (session_timeout > 0)
247 entry->expiration += session_timeout;
249 entry->expiration += dot11RSNAConfigPMKLifetime;
250 entry->akmp = WPA_KEY_MGMT_IEEE8021X;
251 os_memcpy(entry->spa, spa, ETH_ALEN);
252 pmksa_cache_from_eapol_data(entry, eapol);
254 /* Replace an old entry for the same STA (if found) with the new entry
256 pos = pmksa_cache_get(pmksa, spa, NULL);
258 pmksa_cache_free_entry(pmksa, pos);
260 if (pmksa->pmksa_count >= pmksa_cache_max_entries && pmksa->pmksa) {
261 /* Remove the oldest entry to make room for the new entry */
262 wpa_printf(MSG_DEBUG, "RSN: removed the oldest PMKSA cache "
263 "entry (for " MACSTR ") to make room for new one",
264 MAC2STR(pmksa->pmksa->spa));
265 pmksa_cache_free_entry(pmksa, pmksa->pmksa);
268 /* Add the new entry; order by expiration time */
272 if (pos->expiration > entry->expiration)
278 entry->next = pmksa->pmksa;
279 pmksa->pmksa = entry;
281 entry->next = prev->next;
284 entry->hnext = pmksa->pmkid[PMKID_HASH(entry->pmkid)];
285 pmksa->pmkid[PMKID_HASH(entry->pmkid)] = entry;
287 pmksa->pmksa_count++;
288 wpa_printf(MSG_DEBUG, "RSN: added PMKSA cache entry for " MACSTR,
289 MAC2STR(entry->spa));
290 wpa_hexdump(MSG_DEBUG, "RSN: added PMKID", entry->pmkid, PMKID_LEN);
297 * pmksa_cache_deinit - Free all entries in PMKSA cache
298 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
300 void pmksa_cache_deinit(struct rsn_pmksa_cache *pmksa)
302 struct rsn_pmksa_cache_entry *entry, *prev;
308 entry = pmksa->pmksa;
312 _pmksa_cache_free_entry(prev);
314 eloop_cancel_timeout(pmksa_cache_expire, pmksa, NULL);
315 for (i = 0; i < PMKID_HASH_SIZE; i++)
316 pmksa->pmkid[i] = NULL;
322 * pmksa_cache_get - Fetch a PMKSA cache entry
323 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
324 * @spa: Supplicant address or %NULL to match any
325 * @pmkid: PMKID or %NULL to match any
326 * Returns: Pointer to PMKSA cache entry or %NULL if no match was found
328 struct rsn_pmksa_cache_entry * pmksa_cache_get(struct rsn_pmksa_cache *pmksa,
329 const u8 *spa, const u8 *pmkid)
331 struct rsn_pmksa_cache_entry *entry;
334 entry = pmksa->pmkid[PMKID_HASH(pmkid)];
336 entry = pmksa->pmksa;
339 os_memcmp(entry->spa, spa, ETH_ALEN) == 0) &&
341 os_memcmp(entry->pmkid, pmkid, PMKID_LEN) == 0))
343 entry = pmkid ? entry->hnext : entry->next;
350 * pmksa_cache_init - Initialize PMKSA cache
351 * @free_cb: Callback function to be called when a PMKSA cache entry is freed
352 * @ctx: Context pointer for free_cb function
353 * Returns: Pointer to PMKSA cache data or %NULL on failure
355 struct rsn_pmksa_cache *
356 pmksa_cache_init(void (*free_cb)(struct rsn_pmksa_cache_entry *entry,
357 void *ctx), void *ctx)
359 struct rsn_pmksa_cache *pmksa;
361 pmksa = os_zalloc(sizeof(*pmksa));
363 pmksa->free_cb = free_cb;