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 (key->conf.flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)))
138 sdata->crypto_tx_tailroom_needed_cnt--;
140 WARN_ON((key->conf.flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE) &&
141 (key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV));
146 if (ret != -ENOSPC && ret != -EOPNOTSUPP)
147 wiphy_err(key->local->hw.wiphy,
148 "failed to set key (%d, %pM) to hardware (%d)\n",
149 key->conf.keyidx, sta ? sta->addr : bcast_addr, ret);
152 switch (key->conf.cipher) {
153 case WLAN_CIPHER_SUITE_WEP40:
154 case WLAN_CIPHER_SUITE_WEP104:
155 case WLAN_CIPHER_SUITE_TKIP:
156 case WLAN_CIPHER_SUITE_CCMP:
157 case WLAN_CIPHER_SUITE_AES_CMAC:
158 /* all of these we can do in software */
165 static void ieee80211_key_disable_hw_accel(struct ieee80211_key *key)
167 struct ieee80211_sub_if_data *sdata;
168 struct ieee80211_sta *sta;
173 if (!key || !key->local->ops->set_key)
176 assert_key_lock(key->local);
178 if (!(key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE))
181 sta = get_sta_for_key(key);
184 if (!((key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC) ||
185 (key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV) ||
186 (key->conf.flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)))
187 increment_tailroom_need_count(sdata);
189 if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
190 sdata = container_of(sdata->bss,
191 struct ieee80211_sub_if_data,
194 ret = drv_set_key(key->local, DISABLE_KEY, sdata,
198 wiphy_err(key->local->hw.wiphy,
199 "failed to remove key (%d, %pM) from hardware (%d)\n",
200 key->conf.keyidx, sta ? sta->addr : bcast_addr, ret);
202 key->flags &= ~KEY_FLAG_UPLOADED_TO_HARDWARE;
205 void ieee80211_key_removed(struct ieee80211_key_conf *key_conf)
207 struct ieee80211_key *key;
209 key = container_of(key_conf, struct ieee80211_key, conf);
212 assert_key_lock(key->local);
214 key->flags &= ~KEY_FLAG_UPLOADED_TO_HARDWARE;
217 * Flush TX path to avoid attempts to use this key
218 * after this function returns. Until then, drivers
219 * must be prepared to handle the key.
223 EXPORT_SYMBOL_GPL(ieee80211_key_removed);
225 static void __ieee80211_set_default_key(struct ieee80211_sub_if_data *sdata,
226 int idx, bool uni, bool multi)
228 struct ieee80211_key *key = NULL;
230 assert_key_lock(sdata->local);
232 if (idx >= 0 && idx < NUM_DEFAULT_KEYS)
233 key = key_mtx_dereference(sdata->local, sdata->keys[idx]);
236 rcu_assign_pointer(sdata->default_unicast_key, key);
238 rcu_assign_pointer(sdata->default_multicast_key, key);
240 ieee80211_debugfs_key_update_default(sdata);
243 void ieee80211_set_default_key(struct ieee80211_sub_if_data *sdata, int idx,
244 bool uni, bool multi)
246 mutex_lock(&sdata->local->key_mtx);
247 __ieee80211_set_default_key(sdata, idx, uni, multi);
248 mutex_unlock(&sdata->local->key_mtx);
252 __ieee80211_set_default_mgmt_key(struct ieee80211_sub_if_data *sdata, int idx)
254 struct ieee80211_key *key = NULL;
256 assert_key_lock(sdata->local);
258 if (idx >= NUM_DEFAULT_KEYS &&
259 idx < NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS)
260 key = key_mtx_dereference(sdata->local, sdata->keys[idx]);
262 rcu_assign_pointer(sdata->default_mgmt_key, key);
264 ieee80211_debugfs_key_update_default(sdata);
267 void ieee80211_set_default_mgmt_key(struct ieee80211_sub_if_data *sdata,
270 mutex_lock(&sdata->local->key_mtx);
271 __ieee80211_set_default_mgmt_key(sdata, idx);
272 mutex_unlock(&sdata->local->key_mtx);
276 static void __ieee80211_key_replace(struct ieee80211_sub_if_data *sdata,
277 struct sta_info *sta,
279 struct ieee80211_key *old,
280 struct ieee80211_key *new)
283 bool defunikey, defmultikey, defmgmtkey;
286 list_add_tail(&new->list, &sdata->key_list);
288 if (sta && pairwise) {
289 rcu_assign_pointer(sta->ptk, new);
292 idx = old->conf.keyidx;
294 idx = new->conf.keyidx;
295 rcu_assign_pointer(sta->gtk[idx], new);
297 WARN_ON(new && old && new->conf.keyidx != old->conf.keyidx);
300 idx = old->conf.keyidx;
302 idx = new->conf.keyidx;
305 old == key_mtx_dereference(sdata->local,
306 sdata->default_unicast_key);
308 old == key_mtx_dereference(sdata->local,
309 sdata->default_multicast_key);
311 old == key_mtx_dereference(sdata->local,
312 sdata->default_mgmt_key);
314 if (defunikey && !new)
315 __ieee80211_set_default_key(sdata, -1, true, false);
316 if (defmultikey && !new)
317 __ieee80211_set_default_key(sdata, -1, false, true);
318 if (defmgmtkey && !new)
319 __ieee80211_set_default_mgmt_key(sdata, -1);
321 rcu_assign_pointer(sdata->keys[idx], new);
322 if (defunikey && new)
323 __ieee80211_set_default_key(sdata, new->conf.keyidx,
325 if (defmultikey && new)
326 __ieee80211_set_default_key(sdata, new->conf.keyidx,
328 if (defmgmtkey && new)
329 __ieee80211_set_default_mgmt_key(sdata,
334 list_del(&old->list);
337 struct ieee80211_key *ieee80211_key_alloc(u32 cipher, int idx, size_t key_len,
339 size_t seq_len, const u8 *seq)
341 struct ieee80211_key *key;
344 BUG_ON(idx < 0 || idx >= NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS);
346 key = kzalloc(sizeof(struct ieee80211_key) + key_len, GFP_KERNEL);
348 return ERR_PTR(-ENOMEM);
351 * Default to software encryption; we'll later upload the
352 * key to the hardware if possible.
357 key->conf.cipher = cipher;
358 key->conf.keyidx = idx;
359 key->conf.keylen = key_len;
361 case WLAN_CIPHER_SUITE_WEP40:
362 case WLAN_CIPHER_SUITE_WEP104:
363 key->conf.iv_len = WEP_IV_LEN;
364 key->conf.icv_len = WEP_ICV_LEN;
366 case WLAN_CIPHER_SUITE_TKIP:
367 key->conf.iv_len = TKIP_IV_LEN;
368 key->conf.icv_len = TKIP_ICV_LEN;
370 for (i = 0; i < NUM_RX_DATA_QUEUES; i++) {
371 key->u.tkip.rx[i].iv32 =
372 get_unaligned_le32(&seq[2]);
373 key->u.tkip.rx[i].iv16 =
374 get_unaligned_le16(seq);
377 spin_lock_init(&key->u.tkip.txlock);
379 case WLAN_CIPHER_SUITE_CCMP:
380 key->conf.iv_len = CCMP_HDR_LEN;
381 key->conf.icv_len = CCMP_MIC_LEN;
383 for (i = 0; i < NUM_RX_DATA_QUEUES + 1; i++)
384 for (j = 0; j < CCMP_PN_LEN; j++)
385 key->u.ccmp.rx_pn[i][j] =
386 seq[CCMP_PN_LEN - j - 1];
389 * Initialize AES key state here as an optimization so that
390 * it does not need to be initialized for every packet.
392 key->u.ccmp.tfm = ieee80211_aes_key_setup_encrypt(key_data);
393 if (IS_ERR(key->u.ccmp.tfm)) {
394 err = PTR_ERR(key->u.ccmp.tfm);
399 case WLAN_CIPHER_SUITE_AES_CMAC:
400 key->conf.iv_len = 0;
401 key->conf.icv_len = sizeof(struct ieee80211_mmie);
403 for (j = 0; j < 6; j++)
404 key->u.aes_cmac.rx_pn[j] = seq[6 - j - 1];
406 * Initialize AES key state here as an optimization so that
407 * it does not need to be initialized for every packet.
409 key->u.aes_cmac.tfm =
410 ieee80211_aes_cmac_key_setup(key_data);
411 if (IS_ERR(key->u.aes_cmac.tfm)) {
412 err = PTR_ERR(key->u.aes_cmac.tfm);
418 memcpy(key->conf.key, key_data, key_len);
419 INIT_LIST_HEAD(&key->list);
424 static void __ieee80211_key_destroy(struct ieee80211_key *key)
430 * Synchronize so the TX path can no longer be using
431 * this key before we free/remove it.
436 ieee80211_key_disable_hw_accel(key);
438 if (key->conf.cipher == WLAN_CIPHER_SUITE_CCMP)
439 ieee80211_aes_key_free(key->u.ccmp.tfm);
440 if (key->conf.cipher == WLAN_CIPHER_SUITE_AES_CMAC)
441 ieee80211_aes_cmac_key_free(key->u.aes_cmac.tfm);
443 ieee80211_debugfs_key_remove(key);
444 key->sdata->crypto_tx_tailroom_needed_cnt--;
450 int ieee80211_key_link(struct ieee80211_key *key,
451 struct ieee80211_sub_if_data *sdata,
452 struct sta_info *sta)
454 struct ieee80211_key *old_key;
461 pairwise = key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE;
462 idx = key->conf.keyidx;
463 key->local = sdata->local;
469 * some hardware cannot handle TKIP with QoS, so
470 * we indicate whether QoS could be in use.
472 if (test_sta_flag(sta, WLAN_STA_WME))
473 key->conf.flags |= IEEE80211_KEY_FLAG_WMM_STA;
475 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
479 * We're getting a sta pointer in, so must be under
480 * appropriate locking for sta_info_get().
483 /* same here, the AP could be using QoS */
484 ap = sta_info_get(key->sdata, key->sdata->u.mgd.bssid);
486 if (test_sta_flag(ap, WLAN_STA_WME))
488 IEEE80211_KEY_FLAG_WMM_STA;
493 mutex_lock(&sdata->local->key_mtx);
496 old_key = key_mtx_dereference(sdata->local, sta->ptk);
498 old_key = key_mtx_dereference(sdata->local, sta->gtk[idx]);
500 old_key = key_mtx_dereference(sdata->local, sdata->keys[idx]);
502 increment_tailroom_need_count(sdata);
504 __ieee80211_key_replace(sdata, sta, pairwise, old_key, key);
505 __ieee80211_key_destroy(old_key);
507 ieee80211_debugfs_key_add(key);
509 ret = ieee80211_key_enable_hw_accel(key);
511 mutex_unlock(&sdata->local->key_mtx);
516 void __ieee80211_key_free(struct ieee80211_key *key)
522 * Replace key with nothingness if it was ever used.
525 __ieee80211_key_replace(key->sdata, key->sta,
526 key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE,
528 __ieee80211_key_destroy(key);
531 void ieee80211_key_free(struct ieee80211_local *local,
532 struct ieee80211_key *key)
534 mutex_lock(&local->key_mtx);
535 __ieee80211_key_free(key);
536 mutex_unlock(&local->key_mtx);
539 void ieee80211_enable_keys(struct ieee80211_sub_if_data *sdata)
541 struct ieee80211_key *key;
545 if (WARN_ON(!ieee80211_sdata_running(sdata)))
548 mutex_lock(&sdata->local->key_mtx);
550 sdata->crypto_tx_tailroom_needed_cnt = 0;
552 list_for_each_entry(key, &sdata->key_list, list) {
553 increment_tailroom_need_count(sdata);
554 ieee80211_key_enable_hw_accel(key);
557 mutex_unlock(&sdata->local->key_mtx);
560 void ieee80211_iter_keys(struct ieee80211_hw *hw,
561 struct ieee80211_vif *vif,
562 void (*iter)(struct ieee80211_hw *hw,
563 struct ieee80211_vif *vif,
564 struct ieee80211_sta *sta,
565 struct ieee80211_key_conf *key,
569 struct ieee80211_local *local = hw_to_local(hw);
570 struct ieee80211_key *key;
571 struct ieee80211_sub_if_data *sdata;
575 mutex_lock(&local->key_mtx);
577 sdata = vif_to_sdata(vif);
578 list_for_each_entry(key, &sdata->key_list, list)
579 iter(hw, &sdata->vif,
580 key->sta ? &key->sta->sta : NULL,
581 &key->conf, iter_data);
583 list_for_each_entry(sdata, &local->interfaces, list)
584 list_for_each_entry(key, &sdata->key_list, list)
585 iter(hw, &sdata->vif,
586 key->sta ? &key->sta->sta : NULL,
587 &key->conf, iter_data);
589 mutex_unlock(&local->key_mtx);
591 EXPORT_SYMBOL(ieee80211_iter_keys);
593 void ieee80211_disable_keys(struct ieee80211_sub_if_data *sdata)
595 struct ieee80211_key *key;
599 mutex_lock(&sdata->local->key_mtx);
601 list_for_each_entry(key, &sdata->key_list, list)
602 ieee80211_key_disable_hw_accel(key);
604 mutex_unlock(&sdata->local->key_mtx);
607 void ieee80211_free_keys(struct ieee80211_sub_if_data *sdata)
609 struct ieee80211_key *key, *tmp;
611 mutex_lock(&sdata->local->key_mtx);
613 ieee80211_debugfs_key_remove_mgmt_default(sdata);
615 list_for_each_entry_safe(key, tmp, &sdata->key_list, list)
616 __ieee80211_key_free(key);
618 ieee80211_debugfs_key_update_default(sdata);
620 mutex_unlock(&sdata->local->key_mtx);
624 void ieee80211_gtk_rekey_notify(struct ieee80211_vif *vif, const u8 *bssid,
625 const u8 *replay_ctr, gfp_t gfp)
627 struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
629 trace_api_gtk_rekey_notify(sdata, bssid, replay_ctr);
631 cfg80211_gtk_rekey_notify(sdata->dev, bssid, replay_ctr, gfp);
633 EXPORT_SYMBOL_GPL(ieee80211_gtk_rekey_notify);
635 void ieee80211_get_key_tx_seq(struct ieee80211_key_conf *keyconf,
636 struct ieee80211_key_seq *seq)
638 struct ieee80211_key *key;
641 if (WARN_ON(!(keyconf->flags & IEEE80211_KEY_FLAG_GENERATE_IV)))
644 key = container_of(keyconf, struct ieee80211_key, conf);
646 switch (key->conf.cipher) {
647 case WLAN_CIPHER_SUITE_TKIP:
648 seq->tkip.iv32 = key->u.tkip.tx.iv32;
649 seq->tkip.iv16 = key->u.tkip.tx.iv16;
651 case WLAN_CIPHER_SUITE_CCMP:
652 pn64 = atomic64_read(&key->u.ccmp.tx_pn);
653 seq->ccmp.pn[5] = pn64;
654 seq->ccmp.pn[4] = pn64 >> 8;
655 seq->ccmp.pn[3] = pn64 >> 16;
656 seq->ccmp.pn[2] = pn64 >> 24;
657 seq->ccmp.pn[1] = pn64 >> 32;
658 seq->ccmp.pn[0] = pn64 >> 40;
660 case WLAN_CIPHER_SUITE_AES_CMAC:
661 pn64 = atomic64_read(&key->u.aes_cmac.tx_pn);
662 seq->ccmp.pn[5] = pn64;
663 seq->ccmp.pn[4] = pn64 >> 8;
664 seq->ccmp.pn[3] = pn64 >> 16;
665 seq->ccmp.pn[2] = pn64 >> 24;
666 seq->ccmp.pn[1] = pn64 >> 32;
667 seq->ccmp.pn[0] = pn64 >> 40;
673 EXPORT_SYMBOL(ieee80211_get_key_tx_seq);
675 void ieee80211_get_key_rx_seq(struct ieee80211_key_conf *keyconf,
676 int tid, struct ieee80211_key_seq *seq)
678 struct ieee80211_key *key;
681 key = container_of(keyconf, struct ieee80211_key, conf);
683 switch (key->conf.cipher) {
684 case WLAN_CIPHER_SUITE_TKIP:
685 if (WARN_ON(tid < 0 || tid >= NUM_RX_DATA_QUEUES))
687 seq->tkip.iv32 = key->u.tkip.rx[tid].iv32;
688 seq->tkip.iv16 = key->u.tkip.rx[tid].iv16;
690 case WLAN_CIPHER_SUITE_CCMP:
691 if (WARN_ON(tid < -1 || tid >= NUM_RX_DATA_QUEUES))
694 pn = key->u.ccmp.rx_pn[NUM_RX_DATA_QUEUES];
696 pn = key->u.ccmp.rx_pn[tid];
697 memcpy(seq->ccmp.pn, pn, CCMP_PN_LEN);
699 case WLAN_CIPHER_SUITE_AES_CMAC:
700 if (WARN_ON(tid != 0))
702 pn = key->u.aes_cmac.rx_pn;
703 memcpy(seq->aes_cmac.pn, pn, CMAC_PN_LEN);
707 EXPORT_SYMBOL(ieee80211_get_key_rx_seq);