pmksa_cache_auth.c revision fb79edc9df1f20461e90e478363d207348213d35 
1/*
2 * hostapd - PMKSA cache for IEEE 802.11i RSN
3 * Copyright (c) 2004-2008, 2012, Jouni Malinen <j@w1.fi>
4 *
5 * This software may be distributed under the terms of the BSD license.
6 * See README for more details.
7 */
8
9#include "utils/includes.h"
10
11#include "utils/common.h"
12#include "utils/eloop.h"
13#include "eapol_auth/eapol_auth_sm.h"
14#include "eapol_auth/eapol_auth_sm_i.h"
15#include "sta_info.h"
16#include "ap_config.h"
17#include "pmksa_cache_auth.h"
18
19
20static const int pmksa_cache_max_entries = 1024;
21static const int dot11RSNAConfigPMKLifetime = 43200;
22
23struct rsn_pmksa_cache {
24#define PMKID_HASH_SIZE 128
25#define PMKID_HASH(pmkid) (unsigned int) ((pmkid)[0] & 0x7f)
26	struct rsn_pmksa_cache_entry *pmkid[PMKID_HASH_SIZE];
27	struct rsn_pmksa_cache_entry *pmksa;
28	int pmksa_count;
29
30	void (*free_cb)(struct rsn_pmksa_cache_entry *entry, void *ctx);
31	void *ctx;
32};
33
34
35static void pmksa_cache_set_expiration(struct rsn_pmksa_cache *pmksa);
36
37
38static void _pmksa_cache_free_entry(struct rsn_pmksa_cache_entry *entry)
39{
40	if (entry == NULL)
41		return;
42	os_free(entry->identity);
43	wpabuf_free(entry->cui);
44#ifndef CONFIG_NO_RADIUS
45	radius_free_class(&entry->radius_class);
46#endif /* CONFIG_NO_RADIUS */
47	os_free(entry);
48}
49
50
51void pmksa_cache_free_entry(struct rsn_pmksa_cache *pmksa,
52			    struct rsn_pmksa_cache_entry *entry)
53{
54	struct rsn_pmksa_cache_entry *pos, *prev;
55
56	pmksa->pmksa_count--;
57	pmksa->free_cb(entry, pmksa->ctx);
58	pos = pmksa->pmkid[PMKID_HASH(entry->pmkid)];
59	prev = NULL;
60	while (pos) {
61		if (pos == entry) {
62			if (prev != NULL) {
63				prev->hnext = pos->hnext;
64			} else {
65				pmksa->pmkid[PMKID_HASH(entry->pmkid)] =
66					pos->hnext;
67			}
68			break;
69		}
70		prev = pos;
71		pos = pos->hnext;
72	}
73
74	pos = pmksa->pmksa;
75	prev = NULL;
76	while (pos) {
77		if (pos == entry) {
78			if (prev != NULL)
79				prev->next = pos->next;
80			else
81				pmksa->pmksa = pos->next;
82			break;
83		}
84		prev = pos;
85		pos = pos->next;
86	}
87	_pmksa_cache_free_entry(entry);
88}
89
90
91static void pmksa_cache_expire(void *eloop_ctx, void *timeout_ctx)
92{
93	struct rsn_pmksa_cache *pmksa = eloop_ctx;
94	struct os_reltime now;
95
96	os_get_reltime(&now);
97	while (pmksa->pmksa && pmksa->pmksa->expiration <= now.sec) {
98		wpa_printf(MSG_DEBUG, "RSN: expired PMKSA cache entry for "
99			   MACSTR, MAC2STR(pmksa->pmksa->spa));
100		pmksa_cache_free_entry(pmksa, pmksa->pmksa);
101	}
102
103	pmksa_cache_set_expiration(pmksa);
104}
105
106
107static void pmksa_cache_set_expiration(struct rsn_pmksa_cache *pmksa)
108{
109	int sec;
110	struct os_reltime now;
111
112	eloop_cancel_timeout(pmksa_cache_expire, pmksa, NULL);
113	if (pmksa->pmksa == NULL)
114		return;
115	os_get_reltime(&now);
116	sec = pmksa->pmksa->expiration - now.sec;
117	if (sec < 0)
118		sec = 0;
119	eloop_register_timeout(sec + 1, 0, pmksa_cache_expire, pmksa, NULL);
120}
121
122
123static void pmksa_cache_from_eapol_data(struct rsn_pmksa_cache_entry *entry,
124					struct eapol_state_machine *eapol)
125{
126	if (eapol == NULL)
127		return;
128
129	if (eapol->identity) {
130		entry->identity = os_malloc(eapol->identity_len);
131		if (entry->identity) {
132			entry->identity_len = eapol->identity_len;
133			os_memcpy(entry->identity, eapol->identity,
134				  eapol->identity_len);
135		}
136	}
137
138	if (eapol->radius_cui)
139		entry->cui = wpabuf_dup(eapol->radius_cui);
140
141#ifndef CONFIG_NO_RADIUS
142	radius_copy_class(&entry->radius_class, &eapol->radius_class);
143#endif /* CONFIG_NO_RADIUS */
144
145	entry->eap_type_authsrv = eapol->eap_type_authsrv;
146	entry->vlan_id = ((struct sta_info *) eapol->sta)->vlan_id;
147}
148
149
150void pmksa_cache_to_eapol_data(struct rsn_pmksa_cache_entry *entry,
151			       struct eapol_state_machine *eapol)
152{
153	if (entry == NULL || eapol == NULL)
154		return;
155
156	if (entry->identity) {
157		os_free(eapol->identity);
158		eapol->identity = os_malloc(entry->identity_len);
159		if (eapol->identity) {
160			eapol->identity_len = entry->identity_len;
161			os_memcpy(eapol->identity, entry->identity,
162				  entry->identity_len);
163		}
164		wpa_hexdump_ascii(MSG_DEBUG, "STA identity from PMKSA",
165				  eapol->identity, eapol->identity_len);
166	}
167
168	if (entry->cui) {
169		wpabuf_free(eapol->radius_cui);
170		eapol->radius_cui = wpabuf_dup(entry->cui);
171	}
172
173#ifndef CONFIG_NO_RADIUS
174	radius_free_class(&eapol->radius_class);
175	radius_copy_class(&eapol->radius_class, &entry->radius_class);
176#endif /* CONFIG_NO_RADIUS */
177	if (eapol->radius_class.attr) {
178		wpa_printf(MSG_DEBUG, "Copied %lu Class attribute(s) from "
179			   "PMKSA", (unsigned long) eapol->radius_class.count);
180	}
181
182	eapol->eap_type_authsrv = entry->eap_type_authsrv;
183	((struct sta_info *) eapol->sta)->vlan_id = entry->vlan_id;
184}
185
186
187static void pmksa_cache_link_entry(struct rsn_pmksa_cache *pmksa,
188				   struct rsn_pmksa_cache_entry *entry)
189{
190	struct rsn_pmksa_cache_entry *pos, *prev;
191
192	/* Add the new entry; order by expiration time */
193	pos = pmksa->pmksa;
194	prev = NULL;
195	while (pos) {
196		if (pos->expiration > entry->expiration)
197			break;
198		prev = pos;
199		pos = pos->next;
200	}
201	if (prev == NULL) {
202		entry->next = pmksa->pmksa;
203		pmksa->pmksa = entry;
204	} else {
205		entry->next = prev->next;
206		prev->next = entry;
207	}
208	entry->hnext = pmksa->pmkid[PMKID_HASH(entry->pmkid)];
209	pmksa->pmkid[PMKID_HASH(entry->pmkid)] = entry;
210
211	pmksa->pmksa_count++;
212	if (prev == NULL)
213		pmksa_cache_set_expiration(pmksa);
214	wpa_printf(MSG_DEBUG, "RSN: added PMKSA cache entry for " MACSTR,
215		   MAC2STR(entry->spa));
216	wpa_hexdump(MSG_DEBUG, "RSN: added PMKID", entry->pmkid, PMKID_LEN);
217}
218
219
220/**
221 * pmksa_cache_auth_add - Add a PMKSA cache entry
222 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_auth_init()
223 * @pmk: The new pairwise master key
224 * @pmk_len: PMK length in bytes, usually PMK_LEN (32)
225 * @aa: Authenticator address
226 * @spa: Supplicant address
227 * @session_timeout: Session timeout
228 * @eapol: Pointer to EAPOL state machine data
229 * @akmp: WPA_KEY_MGMT_* used in key derivation
230 * Returns: Pointer to the added PMKSA cache entry or %NULL on error
231 *
232 * This function create a PMKSA entry for a new PMK and adds it to the PMKSA
233 * cache. If an old entry is already in the cache for the same Supplicant,
234 * this entry will be replaced with the new entry. PMKID will be calculated
235 * based on the PMK.
236 */
237struct rsn_pmksa_cache_entry *
238pmksa_cache_auth_add(struct rsn_pmksa_cache *pmksa,
239		     const u8 *pmk, size_t pmk_len,
240		const u8 *aa, const u8 *spa, int session_timeout,
241		struct eapol_state_machine *eapol, int akmp)
242{
243	struct rsn_pmksa_cache_entry *entry, *pos;
244	struct os_reltime now;
245
246	if (pmk_len > PMK_LEN)
247		return NULL;
248
249	entry = os_zalloc(sizeof(*entry));
250	if (entry == NULL)
251		return NULL;
252	os_memcpy(entry->pmk, pmk, pmk_len);
253	entry->pmk_len = pmk_len;
254	rsn_pmkid(pmk, pmk_len, aa, spa, entry->pmkid,
255		  wpa_key_mgmt_sha256(akmp));
256	os_get_reltime(&now);
257	entry->expiration = now.sec;
258	if (session_timeout > 0)
259		entry->expiration += session_timeout;
260	else
261		entry->expiration += dot11RSNAConfigPMKLifetime;
262	entry->akmp = akmp;
263	os_memcpy(entry->spa, spa, ETH_ALEN);
264	pmksa_cache_from_eapol_data(entry, eapol);
265
266	/* Replace an old entry for the same STA (if found) with the new entry
267	 */
268	pos = pmksa_cache_auth_get(pmksa, spa, NULL);
269	if (pos)
270		pmksa_cache_free_entry(pmksa, pos);
271
272	if (pmksa->pmksa_count >= pmksa_cache_max_entries && pmksa->pmksa) {
273		/* Remove the oldest entry to make room for the new entry */
274		wpa_printf(MSG_DEBUG, "RSN: removed the oldest PMKSA cache "
275			   "entry (for " MACSTR ") to make room for new one",
276			   MAC2STR(pmksa->pmksa->spa));
277		pmksa_cache_free_entry(pmksa, pmksa->pmksa);
278	}
279
280	pmksa_cache_link_entry(pmksa, entry);
281
282	return entry;
283}
284
285
286struct rsn_pmksa_cache_entry *
287pmksa_cache_add_okc(struct rsn_pmksa_cache *pmksa,
288		    const struct rsn_pmksa_cache_entry *old_entry,
289		    const u8 *aa, const u8 *pmkid)
290{
291	struct rsn_pmksa_cache_entry *entry;
292
293	entry = os_zalloc(sizeof(*entry));
294	if (entry == NULL)
295		return NULL;
296	os_memcpy(entry->pmkid, pmkid, PMKID_LEN);
297	os_memcpy(entry->pmk, old_entry->pmk, old_entry->pmk_len);
298	entry->pmk_len = old_entry->pmk_len;
299	entry->expiration = old_entry->expiration;
300	entry->akmp = old_entry->akmp;
301	os_memcpy(entry->spa, old_entry->spa, ETH_ALEN);
302	entry->opportunistic = 1;
303	if (old_entry->identity) {
304		entry->identity = os_malloc(old_entry->identity_len);
305		if (entry->identity) {
306			entry->identity_len = old_entry->identity_len;
307			os_memcpy(entry->identity, old_entry->identity,
308				  old_entry->identity_len);
309		}
310	}
311	if (old_entry->cui)
312		entry->cui = wpabuf_dup(old_entry->cui);
313#ifndef CONFIG_NO_RADIUS
314	radius_copy_class(&entry->radius_class, &old_entry->radius_class);
315#endif /* CONFIG_NO_RADIUS */
316	entry->eap_type_authsrv = old_entry->eap_type_authsrv;
317	entry->vlan_id = old_entry->vlan_id;
318	entry->opportunistic = 1;
319
320	pmksa_cache_link_entry(pmksa, entry);
321
322	return entry;
323}
324
325
326/**
327 * pmksa_cache_auth_deinit - Free all entries in PMKSA cache
328 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_auth_init()
329 */
330void pmksa_cache_auth_deinit(struct rsn_pmksa_cache *pmksa)
331{
332	struct rsn_pmksa_cache_entry *entry, *prev;
333	int i;
334
335	if (pmksa == NULL)
336		return;
337
338	entry = pmksa->pmksa;
339	while (entry) {
340		prev = entry;
341		entry = entry->next;
342		_pmksa_cache_free_entry(prev);
343	}
344	eloop_cancel_timeout(pmksa_cache_expire, pmksa, NULL);
345	for (i = 0; i < PMKID_HASH_SIZE; i++)
346		pmksa->pmkid[i] = NULL;
347	os_free(pmksa);
348}
349
350
351/**
352 * pmksa_cache_auth_get - Fetch a PMKSA cache entry
353 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_auth_init()
354 * @spa: Supplicant address or %NULL to match any
355 * @pmkid: PMKID or %NULL to match any
356 * Returns: Pointer to PMKSA cache entry or %NULL if no match was found
357 */
358struct rsn_pmksa_cache_entry *
359pmksa_cache_auth_get(struct rsn_pmksa_cache *pmksa,
360		     const u8 *spa, const u8 *pmkid)
361{
362	struct rsn_pmksa_cache_entry *entry;
363
364	if (pmkid)
365		entry = pmksa->pmkid[PMKID_HASH(pmkid)];
366	else
367		entry = pmksa->pmksa;
368	while (entry) {
369		if ((spa == NULL ||
370		     os_memcmp(entry->spa, spa, ETH_ALEN) == 0) &&
371		    (pmkid == NULL ||
372		     os_memcmp(entry->pmkid, pmkid, PMKID_LEN) == 0))
373			return entry;
374		entry = pmkid ? entry->hnext : entry->next;
375	}
376	return NULL;
377}
378
379
380/**
381 * pmksa_cache_get_okc - Fetch a PMKSA cache entry using OKC
382 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_auth_init()
383 * @aa: Authenticator address
384 * @spa: Supplicant address
385 * @pmkid: PMKID
386 * Returns: Pointer to PMKSA cache entry or %NULL if no match was found
387 *
388 * Use opportunistic key caching (OKC) to find a PMK for a supplicant.
389 */
390struct rsn_pmksa_cache_entry * pmksa_cache_get_okc(
391	struct rsn_pmksa_cache *pmksa, const u8 *aa, const u8 *spa,
392	const u8 *pmkid)
393{
394	struct rsn_pmksa_cache_entry *entry;
395	u8 new_pmkid[PMKID_LEN];
396
397	entry = pmksa->pmksa;
398	while (entry) {
399		if (os_memcmp(entry->spa, spa, ETH_ALEN) != 0)
400			continue;
401		rsn_pmkid(entry->pmk, entry->pmk_len, aa, spa, new_pmkid,
402			  wpa_key_mgmt_sha256(entry->akmp));
403		if (os_memcmp(new_pmkid, pmkid, PMKID_LEN) == 0)
404			return entry;
405		entry = entry->next;
406	}
407	return NULL;
408}
409
410
411/**
412 * pmksa_cache_auth_init - Initialize PMKSA cache
413 * @free_cb: Callback function to be called when a PMKSA cache entry is freed
414 * @ctx: Context pointer for free_cb function
415 * Returns: Pointer to PMKSA cache data or %NULL on failure
416 */
417struct rsn_pmksa_cache *
418pmksa_cache_auth_init(void (*free_cb)(struct rsn_pmksa_cache_entry *entry,
419				      void *ctx), void *ctx)
420{
421	struct rsn_pmksa_cache *pmksa;
422
423	pmksa = os_zalloc(sizeof(*pmksa));
424	if (pmksa) {
425		pmksa->free_cb = free_cb;
426		pmksa->ctx = ctx;
427	}
428
429	return pmksa;
430}
431