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 <linux/export.h>
19 #include <net/mac80211.h>
20 #include "ieee80211_i.h"
21 #include "driver-ops.h"
22 #include "debugfs_key.h"
28 * DOC: Key handling basics
30 * Key handling in mac80211 is done based on per-interface (sub_if_data)
31 * keys and per-station keys. Since each station belongs to an interface,
32 * each station key also belongs to that interface.
34 * Hardware acceleration is done on a best-effort basis for algorithms
35 * that are implemented in software, for each key the hardware is asked
36 * to enable that key for offloading but if it cannot do that the key is
37 * simply kept for software encryption (unless it is for an algorithm
38 * that isn't implemented in software).
39 * There is currently no way of knowing whether a key is handled in SW
40 * or HW except by looking into debugfs.
42 * All key management is internally protected by a mutex. Within all
43 * other parts of mac80211, key references are, just as STA structure
44 * references, protected by RCU. Note, however, that some things are
45 * unprotected, namely the key->sta dereferences within the hardware
46 * acceleration functions. This means that sta_info_destroy() must
47 * remove the key which waits for an RCU grace period.
50 static const u8 bcast_addr[ETH_ALEN] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
52 static void assert_key_lock(struct ieee80211_local *local)
54 lockdep_assert_held(&local->key_mtx);
57 static struct ieee80211_sta *get_sta_for_key(struct ieee80211_key *key)
60 return &key->sta->sta;
65 static void increment_tailroom_need_count(struct ieee80211_sub_if_data *sdata)
68 * When this count is zero, SKB resizing for allocating tailroom
69 * for IV or MMIC is skipped. But, this check has created two race
70 * cases in xmit path while transiting from zero count to one:
72 * 1. SKB resize was skipped because no key was added but just before
73 * the xmit key is added and SW encryption kicks off.
75 * 2. SKB resize was skipped because all the keys were hw planted but
76 * just before xmit one of the key is deleted and SW encryption kicks
79 * In both the above case SW encryption will find not enough space for
80 * tailroom and exits with WARN_ON. (See WARN_ONs at wpa.c)
82 * Solution has been explained at
83 * http://mid.gmane.org/1308590980.4322.19.camel@jlt3.sipsolutions.net
86 if (!sdata->crypto_tx_tailroom_needed_cnt++) {
88 * Flush all XMIT packets currently using HW encryption or no
89 * encryption at all if the count transition is from 0 -> 1.
95 static int ieee80211_key_enable_hw_accel(struct ieee80211_key *key)
97 struct ieee80211_sub_if_data *sdata;
98 struct ieee80211_sta *sta;
103 if (!key->local->ops->set_key)
104 goto out_unsupported;
106 assert_key_lock(key->local);
108 sta = get_sta_for_key(key);
111 * If this is a per-STA GTK, check if it
112 * is supported; if not, return.
114 if (sta && !(key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE) &&
115 !(key->local->hw.flags & IEEE80211_HW_SUPPORTS_PER_STA_GTK))
116 goto out_unsupported;
119 if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN) {
121 * The driver doesn't know anything about VLAN interfaces.
122 * Hence, don't send GTKs for VLAN interfaces to the driver.
124 if (!(key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE))
125 goto out_unsupported;
126 sdata = container_of(sdata->bss,
127 struct ieee80211_sub_if_data,
131 ret = drv_set_key(key->local, SET_KEY, sdata, sta, &key->conf);
134 key->flags |= KEY_FLAG_UPLOADED_TO_HARDWARE;
136 if (!((key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC) ||
137 (key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV) ||
138 (key->conf.flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)))
139 sdata->crypto_tx_tailroom_needed_cnt--;
141 WARN_ON((key->conf.flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE) &&
142 (key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV));
147 if (ret != -ENOSPC && ret != -EOPNOTSUPP)
148 wiphy_err(key->local->hw.wiphy,
149 "failed to set key (%d, %pM) to hardware (%d)\n",
150 key->conf.keyidx, sta ? sta->addr : bcast_addr, ret);
153 switch (key->conf.cipher) {
154 case WLAN_CIPHER_SUITE_WEP40:
155 case WLAN_CIPHER_SUITE_WEP104:
156 case WLAN_CIPHER_SUITE_TKIP:
157 case WLAN_CIPHER_SUITE_CCMP:
158 case WLAN_CIPHER_SUITE_AES_CMAC:
159 /* all of these we can do in software */
166 static void ieee80211_key_disable_hw_accel(struct ieee80211_key *key)
168 struct ieee80211_sub_if_data *sdata;
169 struct ieee80211_sta *sta;
174 if (!key || !key->local->ops->set_key)
177 assert_key_lock(key->local);
179 if (!(key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE))
182 sta = get_sta_for_key(key);
185 if (!((key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC) ||
186 (key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV) ||
187 (key->conf.flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)))
188 increment_tailroom_need_count(sdata);
190 if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
191 sdata = container_of(sdata->bss,
192 struct ieee80211_sub_if_data,
195 ret = drv_set_key(key->local, DISABLE_KEY, sdata,
199 wiphy_err(key->local->hw.wiphy,
200 "failed to remove key (%d, %pM) from hardware (%d)\n",
201 key->conf.keyidx, sta ? sta->addr : bcast_addr, ret);
203 key->flags &= ~KEY_FLAG_UPLOADED_TO_HARDWARE;
206 void ieee80211_key_removed(struct ieee80211_key_conf *key_conf)
208 struct ieee80211_key *key;
210 key = container_of(key_conf, struct ieee80211_key, conf);
213 assert_key_lock(key->local);
215 key->flags &= ~KEY_FLAG_UPLOADED_TO_HARDWARE;
218 * Flush TX path to avoid attempts to use this key
219 * after this function returns. Until then, drivers
220 * must be prepared to handle the key.
224 EXPORT_SYMBOL_GPL(ieee80211_key_removed);
226 static void __ieee80211_set_default_key(struct ieee80211_sub_if_data *sdata,
227 int idx, bool uni, bool multi)
229 struct ieee80211_key *key = NULL;
231 assert_key_lock(sdata->local);
233 if (idx >= 0 && idx < NUM_DEFAULT_KEYS)
234 key = key_mtx_dereference(sdata->local, sdata->keys[idx]);
237 rcu_assign_pointer(sdata->default_unicast_key, key);
239 rcu_assign_pointer(sdata->default_multicast_key, key);
241 ieee80211_debugfs_key_update_default(sdata);
244 void ieee80211_set_default_key(struct ieee80211_sub_if_data *sdata, int idx,
245 bool uni, bool multi)
247 mutex_lock(&sdata->local->key_mtx);
248 __ieee80211_set_default_key(sdata, idx, uni, multi);
249 mutex_unlock(&sdata->local->key_mtx);
253 __ieee80211_set_default_mgmt_key(struct ieee80211_sub_if_data *sdata, int idx)
255 struct ieee80211_key *key = NULL;
257 assert_key_lock(sdata->local);
259 if (idx >= NUM_DEFAULT_KEYS &&
260 idx < NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS)
261 key = key_mtx_dereference(sdata->local, sdata->keys[idx]);
263 rcu_assign_pointer(sdata->default_mgmt_key, key);
265 ieee80211_debugfs_key_update_default(sdata);
268 void ieee80211_set_default_mgmt_key(struct ieee80211_sub_if_data *sdata,
271 mutex_lock(&sdata->local->key_mtx);
272 __ieee80211_set_default_mgmt_key(sdata, idx);
273 mutex_unlock(&sdata->local->key_mtx);
277 static void __ieee80211_key_replace(struct ieee80211_sub_if_data *sdata,
278 struct sta_info *sta,
280 struct ieee80211_key *old,
281 struct ieee80211_key *new)
284 bool defunikey, defmultikey, defmgmtkey;
287 list_add_tail(&new->list, &sdata->key_list);
289 if (sta && pairwise) {
290 rcu_assign_pointer(sta->ptk, new);
293 idx = old->conf.keyidx;
295 idx = new->conf.keyidx;
296 rcu_assign_pointer(sta->gtk[idx], new);
298 WARN_ON(new && old && new->conf.keyidx != old->conf.keyidx);
301 idx = old->conf.keyidx;
303 idx = new->conf.keyidx;
306 old == key_mtx_dereference(sdata->local,
307 sdata->default_unicast_key);
309 old == key_mtx_dereference(sdata->local,
310 sdata->default_multicast_key);
312 old == key_mtx_dereference(sdata->local,
313 sdata->default_mgmt_key);
315 if (defunikey && !new)
316 __ieee80211_set_default_key(sdata, -1, true, false);
317 if (defmultikey && !new)
318 __ieee80211_set_default_key(sdata, -1, false, true);
319 if (defmgmtkey && !new)
320 __ieee80211_set_default_mgmt_key(sdata, -1);
322 rcu_assign_pointer(sdata->keys[idx], new);
323 if (defunikey && new)
324 __ieee80211_set_default_key(sdata, new->conf.keyidx,
326 if (defmultikey && new)
327 __ieee80211_set_default_key(sdata, new->conf.keyidx,
329 if (defmgmtkey && new)
330 __ieee80211_set_default_mgmt_key(sdata,
335 list_del(&old->list);
338 struct ieee80211_key *ieee80211_key_alloc(u32 cipher, int idx, size_t key_len,
340 size_t seq_len, const u8 *seq)
342 struct ieee80211_key *key;
345 BUG_ON(idx < 0 || idx >= NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS);
347 key = kzalloc(sizeof(struct ieee80211_key) + key_len, GFP_KERNEL);
349 return ERR_PTR(-ENOMEM);
352 * Default to software encryption; we'll later upload the
353 * key to the hardware if possible.
358 key->conf.cipher = cipher;
359 key->conf.keyidx = idx;
360 key->conf.keylen = key_len;
362 case WLAN_CIPHER_SUITE_WEP40:
363 case WLAN_CIPHER_SUITE_WEP104:
364 key->conf.iv_len = WEP_IV_LEN;
365 key->conf.icv_len = WEP_ICV_LEN;
367 case WLAN_CIPHER_SUITE_TKIP:
368 key->conf.iv_len = TKIP_IV_LEN;
369 key->conf.icv_len = TKIP_ICV_LEN;
371 for (i = 0; i < NUM_RX_DATA_QUEUES; i++) {
372 key->u.tkip.rx[i].iv32 =
373 get_unaligned_le32(&seq[2]);
374 key->u.tkip.rx[i].iv16 =
375 get_unaligned_le16(seq);
378 spin_lock_init(&key->u.tkip.txlock);
380 case WLAN_CIPHER_SUITE_CCMP:
381 key->conf.iv_len = CCMP_HDR_LEN;
382 key->conf.icv_len = CCMP_MIC_LEN;
384 for (i = 0; i < NUM_RX_DATA_QUEUES + 1; i++)
385 for (j = 0; j < CCMP_PN_LEN; j++)
386 key->u.ccmp.rx_pn[i][j] =
387 seq[CCMP_PN_LEN - j - 1];
390 * Initialize AES key state here as an optimization so that
391 * it does not need to be initialized for every packet.
393 key->u.ccmp.tfm = ieee80211_aes_key_setup_encrypt(key_data);
394 if (IS_ERR(key->u.ccmp.tfm)) {
395 err = PTR_ERR(key->u.ccmp.tfm);
400 case WLAN_CIPHER_SUITE_AES_CMAC:
401 key->conf.iv_len = 0;
402 key->conf.icv_len = sizeof(struct ieee80211_mmie);
404 for (j = 0; j < 6; j++)
405 key->u.aes_cmac.rx_pn[j] = seq[6 - j - 1];
407 * Initialize AES key state here as an optimization so that
408 * it does not need to be initialized for every packet.
410 key->u.aes_cmac.tfm =
411 ieee80211_aes_cmac_key_setup(key_data);
412 if (IS_ERR(key->u.aes_cmac.tfm)) {
413 err = PTR_ERR(key->u.aes_cmac.tfm);
419 memcpy(key->conf.key, key_data, key_len);
420 INIT_LIST_HEAD(&key->list);
425 static void __ieee80211_key_destroy(struct ieee80211_key *key)
431 * Synchronize so the TX path can no longer be using
432 * this key before we free/remove it.
437 ieee80211_key_disable_hw_accel(key);
439 if (key->conf.cipher == WLAN_CIPHER_SUITE_CCMP)
440 ieee80211_aes_key_free(key->u.ccmp.tfm);
441 if (key->conf.cipher == WLAN_CIPHER_SUITE_AES_CMAC)
442 ieee80211_aes_cmac_key_free(key->u.aes_cmac.tfm);
444 ieee80211_debugfs_key_remove(key);
445 key->sdata->crypto_tx_tailroom_needed_cnt--;
451 int ieee80211_key_link(struct ieee80211_key *key,
452 struct ieee80211_sub_if_data *sdata,
453 struct sta_info *sta)
455 struct ieee80211_key *old_key;
462 pairwise = key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE;
463 idx = key->conf.keyidx;
464 key->local = sdata->local;
470 * some hardware cannot handle TKIP with QoS, so
471 * we indicate whether QoS could be in use.
473 if (test_sta_flag(sta, WLAN_STA_WME))
474 key->conf.flags |= IEEE80211_KEY_FLAG_WMM_STA;
476 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
480 * We're getting a sta pointer in, so must be under
481 * appropriate locking for sta_info_get().
484 /* same here, the AP could be using QoS */
485 ap = sta_info_get(key->sdata, key->sdata->u.mgd.bssid);
487 if (test_sta_flag(ap, WLAN_STA_WME))
489 IEEE80211_KEY_FLAG_WMM_STA;
494 mutex_lock(&sdata->local->key_mtx);
497 old_key = key_mtx_dereference(sdata->local, sta->ptk);
499 old_key = key_mtx_dereference(sdata->local, sta->gtk[idx]);
501 old_key = key_mtx_dereference(sdata->local, sdata->keys[idx]);
503 increment_tailroom_need_count(sdata);
505 __ieee80211_key_replace(sdata, sta, pairwise, old_key, key);
506 __ieee80211_key_destroy(old_key);
508 ieee80211_debugfs_key_add(key);
510 ret = ieee80211_key_enable_hw_accel(key);
512 mutex_unlock(&sdata->local->key_mtx);
517 void __ieee80211_key_free(struct ieee80211_key *key)
523 * Replace key with nothingness if it was ever used.
526 __ieee80211_key_replace(key->sdata, key->sta,
527 key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE,
529 __ieee80211_key_destroy(key);
532 void ieee80211_key_free(struct ieee80211_local *local,
533 struct ieee80211_key *key)
535 mutex_lock(&local->key_mtx);
536 __ieee80211_key_free(key);
537 mutex_unlock(&local->key_mtx);
540 void ieee80211_enable_keys(struct ieee80211_sub_if_data *sdata)
542 struct ieee80211_key *key;
546 if (WARN_ON(!ieee80211_sdata_running(sdata)))
549 mutex_lock(&sdata->local->key_mtx);
551 sdata->crypto_tx_tailroom_needed_cnt = 0;
553 list_for_each_entry(key, &sdata->key_list, list) {
554 increment_tailroom_need_count(sdata);
555 ieee80211_key_enable_hw_accel(key);
558 mutex_unlock(&sdata->local->key_mtx);
561 void ieee80211_iter_keys(struct ieee80211_hw *hw,
562 struct ieee80211_vif *vif,
563 void (*iter)(struct ieee80211_hw *hw,
564 struct ieee80211_vif *vif,
565 struct ieee80211_sta *sta,
566 struct ieee80211_key_conf *key,
570 struct ieee80211_local *local = hw_to_local(hw);
571 struct ieee80211_key *key;
572 struct ieee80211_sub_if_data *sdata;
576 mutex_lock(&local->key_mtx);
578 sdata = vif_to_sdata(vif);
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 list_for_each_entry(sdata, &local->interfaces, list)
585 list_for_each_entry(key, &sdata->key_list, list)
586 iter(hw, &sdata->vif,
587 key->sta ? &key->sta->sta : NULL,
588 &key->conf, iter_data);
590 mutex_unlock(&local->key_mtx);
592 EXPORT_SYMBOL(ieee80211_iter_keys);
594 void ieee80211_disable_keys(struct ieee80211_sub_if_data *sdata)
596 struct ieee80211_key *key;
600 mutex_lock(&sdata->local->key_mtx);
602 list_for_each_entry(key, &sdata->key_list, list)
603 ieee80211_key_disable_hw_accel(key);
605 mutex_unlock(&sdata->local->key_mtx);
608 void ieee80211_free_keys(struct ieee80211_sub_if_data *sdata)
610 struct ieee80211_key *key, *tmp;
612 mutex_lock(&sdata->local->key_mtx);
614 ieee80211_debugfs_key_remove_mgmt_default(sdata);
616 list_for_each_entry_safe(key, tmp, &sdata->key_list, list)
617 __ieee80211_key_free(key);
619 ieee80211_debugfs_key_update_default(sdata);
621 mutex_unlock(&sdata->local->key_mtx);
625 void ieee80211_gtk_rekey_notify(struct ieee80211_vif *vif, const u8 *bssid,
626 const u8 *replay_ctr, gfp_t gfp)
628 struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
630 trace_api_gtk_rekey_notify(sdata, bssid, replay_ctr);
632 cfg80211_gtk_rekey_notify(sdata->dev, bssid, replay_ctr, gfp);
634 EXPORT_SYMBOL_GPL(ieee80211_gtk_rekey_notify);
636 void ieee80211_get_key_tx_seq(struct ieee80211_key_conf *keyconf,
637 struct ieee80211_key_seq *seq)
639 struct ieee80211_key *key;
642 if (WARN_ON(!(keyconf->flags & IEEE80211_KEY_FLAG_GENERATE_IV)))
645 key = container_of(keyconf, struct ieee80211_key, conf);
647 switch (key->conf.cipher) {
648 case WLAN_CIPHER_SUITE_TKIP:
649 seq->tkip.iv32 = key->u.tkip.tx.iv32;
650 seq->tkip.iv16 = key->u.tkip.tx.iv16;
652 case WLAN_CIPHER_SUITE_CCMP:
653 pn64 = atomic64_read(&key->u.ccmp.tx_pn);
654 seq->ccmp.pn[5] = pn64;
655 seq->ccmp.pn[4] = pn64 >> 8;
656 seq->ccmp.pn[3] = pn64 >> 16;
657 seq->ccmp.pn[2] = pn64 >> 24;
658 seq->ccmp.pn[1] = pn64 >> 32;
659 seq->ccmp.pn[0] = pn64 >> 40;
661 case WLAN_CIPHER_SUITE_AES_CMAC:
662 pn64 = atomic64_read(&key->u.aes_cmac.tx_pn);
663 seq->ccmp.pn[5] = pn64;
664 seq->ccmp.pn[4] = pn64 >> 8;
665 seq->ccmp.pn[3] = pn64 >> 16;
666 seq->ccmp.pn[2] = pn64 >> 24;
667 seq->ccmp.pn[1] = pn64 >> 32;
668 seq->ccmp.pn[0] = pn64 >> 40;
674 EXPORT_SYMBOL(ieee80211_get_key_tx_seq);
676 void ieee80211_get_key_rx_seq(struct ieee80211_key_conf *keyconf,
677 int tid, struct ieee80211_key_seq *seq)
679 struct ieee80211_key *key;
682 key = container_of(keyconf, struct ieee80211_key, conf);
684 switch (key->conf.cipher) {
685 case WLAN_CIPHER_SUITE_TKIP:
686 if (WARN_ON(tid < 0 || tid >= NUM_RX_DATA_QUEUES))
688 seq->tkip.iv32 = key->u.tkip.rx[tid].iv32;
689 seq->tkip.iv16 = key->u.tkip.rx[tid].iv16;
691 case WLAN_CIPHER_SUITE_CCMP:
692 if (WARN_ON(tid < -1 || tid >= NUM_RX_DATA_QUEUES))
695 pn = key->u.ccmp.rx_pn[NUM_RX_DATA_QUEUES];
697 pn = key->u.ccmp.rx_pn[tid];
698 memcpy(seq->ccmp.pn, pn, CCMP_PN_LEN);
700 case WLAN_CIPHER_SUITE_AES_CMAC:
701 if (WARN_ON(tid != 0))
703 pn = key->u.aes_cmac.rx_pn;
704 memcpy(seq->aes_cmac.pn, pn, CMAC_PN_LEN);
708 EXPORT_SYMBOL(ieee80211_get_key_rx_seq);