2 * Copyright 2002-2005, Instant802 Networks, Inc.
3 * Copyright 2005-2006, Devicescape Software, Inc.
4 * Copyright 2006-2007 Jiri Benc <jbenc@suse.cz>
5 * Copyright 2007-2008 Johannes Berg <johannes@sipsolutions.net>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
12 #include <linux/if_ether.h>
13 #include <linux/etherdevice.h>
14 #include <linux/list.h>
15 #include <linux/rcupdate.h>
16 #include <linux/rtnetlink.h>
17 #include <linux/slab.h>
18 #include <net/mac80211.h>
19 #include "ieee80211_i.h"
20 #include "driver-ops.h"
21 #include "debugfs_key.h"
27 * DOC: Key handling basics
29 * Key handling in mac80211 is done based on per-interface (sub_if_data)
30 * keys and per-station keys. Since each station belongs to an interface,
31 * each station key also belongs to that interface.
33 * Hardware acceleration is done on a best-effort basis for algorithms
34 * that are implemented in software, for each key the hardware is asked
35 * to enable that key for offloading but if it cannot do that the key is
36 * simply kept for software encryption (unless it is for an algorithm
37 * that isn't implemented in software).
38 * There is currently no way of knowing whether a key is handled in SW
39 * or HW except by looking into debugfs.
41 * All key management is internally protected by a mutex. Within all
42 * other parts of mac80211, key references are, just as STA structure
43 * references, protected by RCU. Note, however, that some things are
44 * unprotected, namely the key->sta dereferences within the hardware
45 * acceleration functions. This means that sta_info_destroy() must
46 * remove the key which waits for an RCU grace period.
49 static const u8 bcast_addr[ETH_ALEN] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
51 static void assert_key_lock(struct ieee80211_local *local)
53 lockdep_assert_held(&local->key_mtx);
56 static struct ieee80211_sta *get_sta_for_key(struct ieee80211_key *key)
59 return &key->sta->sta;
64 static void increment_tailroom_need_count(struct ieee80211_sub_if_data *sdata)
67 * When this count is zero, SKB resizing for allocating tailroom
68 * for IV or MMIC is skipped. But, this check has created two race
69 * cases in xmit path while transiting from zero count to one:
71 * 1. SKB resize was skipped because no key was added but just before
72 * the xmit key is added and SW encryption kicks off.
74 * 2. SKB resize was skipped because all the keys were hw planted but
75 * just before xmit one of the key is deleted and SW encryption kicks
78 * In both the above case SW encryption will find not enough space for
79 * tailroom and exits with WARN_ON. (See WARN_ONs at wpa.c)
81 * Solution has been explained at
82 * http://mid.gmane.org/1308590980.4322.19.camel@jlt3.sipsolutions.net
85 if (!sdata->crypto_tx_tailroom_needed_cnt++) {
87 * Flush all XMIT packets currently using HW encryption or no
88 * encryption at all if the count transition is from 0 -> 1.
94 static int ieee80211_key_enable_hw_accel(struct ieee80211_key *key)
96 struct ieee80211_sub_if_data *sdata;
97 struct ieee80211_sta *sta;
102 if (!key->local->ops->set_key)
103 goto out_unsupported;
105 assert_key_lock(key->local);
107 sta = get_sta_for_key(key);
110 * If this is a per-STA GTK, check if it
111 * is supported; if not, return.
113 if (sta && !(key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE) &&
114 !(key->local->hw.flags & IEEE80211_HW_SUPPORTS_PER_STA_GTK))
115 goto out_unsupported;
118 if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN) {
120 * The driver doesn't know anything about VLAN interfaces.
121 * Hence, don't send GTKs for VLAN interfaces to the driver.
123 if (!(key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE))
124 goto out_unsupported;
125 sdata = container_of(sdata->bss,
126 struct ieee80211_sub_if_data,
130 ret = drv_set_key(key->local, SET_KEY, sdata, sta, &key->conf);
133 key->flags |= KEY_FLAG_UPLOADED_TO_HARDWARE;
135 if (!((key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC) ||
136 (key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV)))
137 sdata->crypto_tx_tailroom_needed_cnt--;
142 if (ret != -ENOSPC && ret != -EOPNOTSUPP)
143 wiphy_err(key->local->hw.wiphy,
144 "failed to set key (%d, %pM) to hardware (%d)\n",
145 key->conf.keyidx, sta ? sta->addr : bcast_addr, ret);
148 switch (key->conf.cipher) {
149 case WLAN_CIPHER_SUITE_WEP40:
150 case WLAN_CIPHER_SUITE_WEP104:
151 case WLAN_CIPHER_SUITE_TKIP:
152 case WLAN_CIPHER_SUITE_CCMP:
153 case WLAN_CIPHER_SUITE_AES_CMAC:
154 /* all of these we can do in software */
161 static void ieee80211_key_disable_hw_accel(struct ieee80211_key *key)
163 struct ieee80211_sub_if_data *sdata;
164 struct ieee80211_sta *sta;
169 if (!key || !key->local->ops->set_key)
172 assert_key_lock(key->local);
174 if (!(key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE))
177 sta = get_sta_for_key(key);
180 if (!((key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC) ||
181 (key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV)))
182 increment_tailroom_need_count(sdata);
184 if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
185 sdata = container_of(sdata->bss,
186 struct ieee80211_sub_if_data,
189 ret = drv_set_key(key->local, DISABLE_KEY, sdata,
193 wiphy_err(key->local->hw.wiphy,
194 "failed to remove key (%d, %pM) from hardware (%d)\n",
195 key->conf.keyidx, sta ? sta->addr : bcast_addr, ret);
197 key->flags &= ~KEY_FLAG_UPLOADED_TO_HARDWARE;
200 void ieee80211_key_removed(struct ieee80211_key_conf *key_conf)
202 struct ieee80211_key *key;
204 key = container_of(key_conf, struct ieee80211_key, conf);
207 assert_key_lock(key->local);
209 key->flags &= ~KEY_FLAG_UPLOADED_TO_HARDWARE;
212 * Flush TX path to avoid attempts to use this key
213 * after this function returns. Until then, drivers
214 * must be prepared to handle the key.
218 EXPORT_SYMBOL_GPL(ieee80211_key_removed);
220 static void __ieee80211_set_default_key(struct ieee80211_sub_if_data *sdata,
221 int idx, bool uni, bool multi)
223 struct ieee80211_key *key = NULL;
225 assert_key_lock(sdata->local);
227 if (idx >= 0 && idx < NUM_DEFAULT_KEYS)
228 key = key_mtx_dereference(sdata->local, sdata->keys[idx]);
231 rcu_assign_pointer(sdata->default_unicast_key, key);
233 rcu_assign_pointer(sdata->default_multicast_key, key);
235 ieee80211_debugfs_key_update_default(sdata);
238 void ieee80211_set_default_key(struct ieee80211_sub_if_data *sdata, int idx,
239 bool uni, bool multi)
241 mutex_lock(&sdata->local->key_mtx);
242 __ieee80211_set_default_key(sdata, idx, uni, multi);
243 mutex_unlock(&sdata->local->key_mtx);
247 __ieee80211_set_default_mgmt_key(struct ieee80211_sub_if_data *sdata, int idx)
249 struct ieee80211_key *key = NULL;
251 assert_key_lock(sdata->local);
253 if (idx >= NUM_DEFAULT_KEYS &&
254 idx < NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS)
255 key = key_mtx_dereference(sdata->local, sdata->keys[idx]);
257 rcu_assign_pointer(sdata->default_mgmt_key, key);
259 ieee80211_debugfs_key_update_default(sdata);
262 void ieee80211_set_default_mgmt_key(struct ieee80211_sub_if_data *sdata,
265 mutex_lock(&sdata->local->key_mtx);
266 __ieee80211_set_default_mgmt_key(sdata, idx);
267 mutex_unlock(&sdata->local->key_mtx);
271 static void __ieee80211_key_replace(struct ieee80211_sub_if_data *sdata,
272 struct sta_info *sta,
274 struct ieee80211_key *old,
275 struct ieee80211_key *new)
278 bool defunikey, defmultikey, defmgmtkey;
281 list_add(&new->list, &sdata->key_list);
283 if (sta && pairwise) {
284 rcu_assign_pointer(sta->ptk, new);
287 idx = old->conf.keyidx;
289 idx = new->conf.keyidx;
290 rcu_assign_pointer(sta->gtk[idx], new);
292 WARN_ON(new && old && new->conf.keyidx != old->conf.keyidx);
295 idx = old->conf.keyidx;
297 idx = new->conf.keyidx;
300 old == key_mtx_dereference(sdata->local,
301 sdata->default_unicast_key);
303 old == key_mtx_dereference(sdata->local,
304 sdata->default_multicast_key);
306 old == key_mtx_dereference(sdata->local,
307 sdata->default_mgmt_key);
309 if (defunikey && !new)
310 __ieee80211_set_default_key(sdata, -1, true, false);
311 if (defmultikey && !new)
312 __ieee80211_set_default_key(sdata, -1, false, true);
313 if (defmgmtkey && !new)
314 __ieee80211_set_default_mgmt_key(sdata, -1);
316 rcu_assign_pointer(sdata->keys[idx], new);
317 if (defunikey && new)
318 __ieee80211_set_default_key(sdata, new->conf.keyidx,
320 if (defmultikey && new)
321 __ieee80211_set_default_key(sdata, new->conf.keyidx,
323 if (defmgmtkey && new)
324 __ieee80211_set_default_mgmt_key(sdata,
329 list_del(&old->list);
332 struct ieee80211_key *ieee80211_key_alloc(u32 cipher, int idx, size_t key_len,
334 size_t seq_len, const u8 *seq)
336 struct ieee80211_key *key;
339 BUG_ON(idx < 0 || idx >= NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS);
341 key = kzalloc(sizeof(struct ieee80211_key) + key_len, GFP_KERNEL);
343 return ERR_PTR(-ENOMEM);
346 * Default to software encryption; we'll later upload the
347 * key to the hardware if possible.
352 key->conf.cipher = cipher;
353 key->conf.keyidx = idx;
354 key->conf.keylen = key_len;
356 case WLAN_CIPHER_SUITE_WEP40:
357 case WLAN_CIPHER_SUITE_WEP104:
358 key->conf.iv_len = WEP_IV_LEN;
359 key->conf.icv_len = WEP_ICV_LEN;
361 case WLAN_CIPHER_SUITE_TKIP:
362 key->conf.iv_len = TKIP_IV_LEN;
363 key->conf.icv_len = TKIP_ICV_LEN;
365 for (i = 0; i < NUM_RX_DATA_QUEUES; i++) {
366 key->u.tkip.rx[i].iv32 =
367 get_unaligned_le32(&seq[2]);
368 key->u.tkip.rx[i].iv16 =
369 get_unaligned_le16(seq);
372 spin_lock_init(&key->u.tkip.txlock);
374 case WLAN_CIPHER_SUITE_CCMP:
375 key->conf.iv_len = CCMP_HDR_LEN;
376 key->conf.icv_len = CCMP_MIC_LEN;
378 for (i = 0; i < NUM_RX_DATA_QUEUES + 1; i++)
379 for (j = 0; j < CCMP_PN_LEN; j++)
380 key->u.ccmp.rx_pn[i][j] =
381 seq[CCMP_PN_LEN - j - 1];
384 * Initialize AES key state here as an optimization so that
385 * it does not need to be initialized for every packet.
387 key->u.ccmp.tfm = ieee80211_aes_key_setup_encrypt(key_data);
388 if (IS_ERR(key->u.ccmp.tfm)) {
389 err = PTR_ERR(key->u.ccmp.tfm);
394 case WLAN_CIPHER_SUITE_AES_CMAC:
395 key->conf.iv_len = 0;
396 key->conf.icv_len = sizeof(struct ieee80211_mmie);
398 for (j = 0; j < 6; j++)
399 key->u.aes_cmac.rx_pn[j] = seq[6 - j - 1];
401 * Initialize AES key state here as an optimization so that
402 * it does not need to be initialized for every packet.
404 key->u.aes_cmac.tfm =
405 ieee80211_aes_cmac_key_setup(key_data);
406 if (IS_ERR(key->u.aes_cmac.tfm)) {
407 err = PTR_ERR(key->u.aes_cmac.tfm);
413 memcpy(key->conf.key, key_data, key_len);
414 INIT_LIST_HEAD(&key->list);
419 static void __ieee80211_key_destroy(struct ieee80211_key *key)
425 * Synchronize so the TX path can no longer be using
426 * this key before we free/remove it.
431 ieee80211_key_disable_hw_accel(key);
433 if (key->conf.cipher == WLAN_CIPHER_SUITE_CCMP)
434 ieee80211_aes_key_free(key->u.ccmp.tfm);
435 if (key->conf.cipher == WLAN_CIPHER_SUITE_AES_CMAC)
436 ieee80211_aes_cmac_key_free(key->u.aes_cmac.tfm);
438 ieee80211_debugfs_key_remove(key);
439 key->sdata->crypto_tx_tailroom_needed_cnt--;
445 int ieee80211_key_link(struct ieee80211_key *key,
446 struct ieee80211_sub_if_data *sdata,
447 struct sta_info *sta)
449 struct ieee80211_key *old_key;
456 pairwise = key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE;
457 idx = key->conf.keyidx;
458 key->local = sdata->local;
464 * some hardware cannot handle TKIP with QoS, so
465 * we indicate whether QoS could be in use.
467 if (test_sta_flags(sta, WLAN_STA_WME))
468 key->conf.flags |= IEEE80211_KEY_FLAG_WMM_STA;
470 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
474 * We're getting a sta pointer in, so must be under
475 * appropriate locking for sta_info_get().
478 /* same here, the AP could be using QoS */
479 ap = sta_info_get(key->sdata, key->sdata->u.mgd.bssid);
481 if (test_sta_flags(ap, WLAN_STA_WME))
483 IEEE80211_KEY_FLAG_WMM_STA;
488 mutex_lock(&sdata->local->key_mtx);
491 old_key = key_mtx_dereference(sdata->local, sta->ptk);
493 old_key = key_mtx_dereference(sdata->local, sta->gtk[idx]);
495 old_key = key_mtx_dereference(sdata->local, sdata->keys[idx]);
497 increment_tailroom_need_count(sdata);
499 __ieee80211_key_replace(sdata, sta, pairwise, old_key, key);
500 __ieee80211_key_destroy(old_key);
502 ieee80211_debugfs_key_add(key);
504 ret = ieee80211_key_enable_hw_accel(key);
506 mutex_unlock(&sdata->local->key_mtx);
511 void __ieee80211_key_free(struct ieee80211_key *key)
517 * Replace key with nothingness if it was ever used.
520 __ieee80211_key_replace(key->sdata, key->sta,
521 key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE,
523 __ieee80211_key_destroy(key);
526 void ieee80211_key_free(struct ieee80211_local *local,
527 struct ieee80211_key *key)
529 mutex_lock(&local->key_mtx);
530 __ieee80211_key_free(key);
531 mutex_unlock(&local->key_mtx);
534 void ieee80211_enable_keys(struct ieee80211_sub_if_data *sdata)
536 struct ieee80211_key *key;
540 if (WARN_ON(!ieee80211_sdata_running(sdata)))
543 mutex_lock(&sdata->local->key_mtx);
545 sdata->crypto_tx_tailroom_needed_cnt = 0;
547 list_for_each_entry(key, &sdata->key_list, list) {
548 increment_tailroom_need_count(sdata);
549 ieee80211_key_enable_hw_accel(key);
552 mutex_unlock(&sdata->local->key_mtx);
555 void ieee80211_iter_keys(struct ieee80211_hw *hw,
556 struct ieee80211_vif *vif,
557 void (*iter)(struct ieee80211_hw *hw,
558 struct ieee80211_vif *vif,
559 struct ieee80211_sta *sta,
560 struct ieee80211_key_conf *key,
564 struct ieee80211_local *local = hw_to_local(hw);
565 struct ieee80211_key *key;
566 struct ieee80211_sub_if_data *sdata;
570 mutex_lock(&local->key_mtx);
572 sdata = vif_to_sdata(vif);
573 list_for_each_entry(key, &sdata->key_list, list)
574 iter(hw, &sdata->vif,
575 key->sta ? &key->sta->sta : NULL,
576 &key->conf, iter_data);
578 list_for_each_entry(sdata, &local->interfaces, list)
579 list_for_each_entry(key, &sdata->key_list, list)
580 iter(hw, &sdata->vif,
581 key->sta ? &key->sta->sta : NULL,
582 &key->conf, iter_data);
584 mutex_unlock(&local->key_mtx);
586 EXPORT_SYMBOL(ieee80211_iter_keys);
588 void ieee80211_disable_keys(struct ieee80211_sub_if_data *sdata)
590 struct ieee80211_key *key;
594 mutex_lock(&sdata->local->key_mtx);
596 list_for_each_entry(key, &sdata->key_list, list)
597 ieee80211_key_disable_hw_accel(key);
599 mutex_unlock(&sdata->local->key_mtx);
602 void ieee80211_free_keys(struct ieee80211_sub_if_data *sdata)
604 struct ieee80211_key *key, *tmp;
606 mutex_lock(&sdata->local->key_mtx);
608 ieee80211_debugfs_key_remove_mgmt_default(sdata);
610 list_for_each_entry_safe(key, tmp, &sdata->key_list, list)
611 __ieee80211_key_free(key);
613 ieee80211_debugfs_key_update_default(sdata);
615 mutex_unlock(&sdata->local->key_mtx);
619 void ieee80211_gtk_rekey_notify(struct ieee80211_vif *vif, const u8 *bssid,
620 const u8 *replay_ctr, gfp_t gfp)
622 struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
624 trace_api_gtk_rekey_notify(sdata, bssid, replay_ctr);
626 cfg80211_gtk_rekey_notify(sdata->dev, bssid, replay_ctr, gfp);
628 EXPORT_SYMBOL_GPL(ieee80211_gtk_rekey_notify);
630 void ieee80211_get_key_tx_seq(struct ieee80211_key_conf *keyconf,
631 struct ieee80211_key_seq *seq)
633 struct ieee80211_key *key;
636 if (WARN_ON(!(keyconf->flags & IEEE80211_KEY_FLAG_GENERATE_IV)))
639 key = container_of(keyconf, struct ieee80211_key, conf);
641 switch (key->conf.cipher) {
642 case WLAN_CIPHER_SUITE_TKIP:
643 seq->tkip.iv32 = key->u.tkip.tx.iv32;
644 seq->tkip.iv16 = key->u.tkip.tx.iv16;
646 case WLAN_CIPHER_SUITE_CCMP:
647 pn64 = atomic64_read(&key->u.ccmp.tx_pn);
648 seq->ccmp.pn[5] = pn64;
649 seq->ccmp.pn[4] = pn64 >> 8;
650 seq->ccmp.pn[3] = pn64 >> 16;
651 seq->ccmp.pn[2] = pn64 >> 24;
652 seq->ccmp.pn[1] = pn64 >> 32;
653 seq->ccmp.pn[0] = pn64 >> 40;
655 case WLAN_CIPHER_SUITE_AES_CMAC:
656 pn64 = atomic64_read(&key->u.aes_cmac.tx_pn);
657 seq->ccmp.pn[5] = pn64;
658 seq->ccmp.pn[4] = pn64 >> 8;
659 seq->ccmp.pn[3] = pn64 >> 16;
660 seq->ccmp.pn[2] = pn64 >> 24;
661 seq->ccmp.pn[1] = pn64 >> 32;
662 seq->ccmp.pn[0] = pn64 >> 40;
668 EXPORT_SYMBOL(ieee80211_get_key_tx_seq);
670 void ieee80211_get_key_rx_seq(struct ieee80211_key_conf *keyconf,
671 int tid, struct ieee80211_key_seq *seq)
673 struct ieee80211_key *key;
676 key = container_of(keyconf, struct ieee80211_key, conf);
678 switch (key->conf.cipher) {
679 case WLAN_CIPHER_SUITE_TKIP:
680 if (WARN_ON(tid < 0 || tid >= NUM_RX_DATA_QUEUES))
682 seq->tkip.iv32 = key->u.tkip.rx[tid].iv32;
683 seq->tkip.iv16 = key->u.tkip.rx[tid].iv16;
685 case WLAN_CIPHER_SUITE_CCMP:
686 if (WARN_ON(tid < -1 || tid >= NUM_RX_DATA_QUEUES))
689 pn = key->u.ccmp.rx_pn[NUM_RX_DATA_QUEUES];
691 pn = key->u.ccmp.rx_pn[tid];
692 memcpy(seq->ccmp.pn, pn, CCMP_PN_LEN);
694 case WLAN_CIPHER_SUITE_AES_CMAC:
695 if (WARN_ON(tid != 0))
697 pn = key->u.aes_cmac.rx_pn;
698 memcpy(seq->aes_cmac.pn, pn, CMAC_PN_LEN);
702 EXPORT_SYMBOL(ieee80211_get_key_rx_seq);