linux/net/mac80211/key.c
Johannes Berg d26ad3771f mac80211: clean up asm/unaligned.h inclusion
Some files implicitly get this via mesh.h
which itself doesn't need it, so move the
inclusion into the right files. Some other
files don't need it at all but include it,
so remove it from there.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2012-02-27 14:06:32 -05:00

700 lines
18 KiB
C

/*
* Copyright 2002-2005, Instant802 Networks, Inc.
* Copyright 2005-2006, Devicescape Software, Inc.
* Copyright 2006-2007 Jiri Benc <jbenc@suse.cz>
* Copyright 2007-2008 Johannes Berg <johannes@sipsolutions.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/if_ether.h>
#include <linux/etherdevice.h>
#include <linux/list.h>
#include <linux/rcupdate.h>
#include <linux/rtnetlink.h>
#include <linux/slab.h>
#include <linux/export.h>
#include <net/mac80211.h>
#include <asm/unaligned.h>
#include "ieee80211_i.h"
#include "driver-ops.h"
#include "debugfs_key.h"
#include "aes_ccm.h"
#include "aes_cmac.h"
/**
* DOC: Key handling basics
*
* Key handling in mac80211 is done based on per-interface (sub_if_data)
* keys and per-station keys. Since each station belongs to an interface,
* each station key also belongs to that interface.
*
* Hardware acceleration is done on a best-effort basis for algorithms
* that are implemented in software, for each key the hardware is asked
* to enable that key for offloading but if it cannot do that the key is
* simply kept for software encryption (unless it is for an algorithm
* that isn't implemented in software).
* There is currently no way of knowing whether a key is handled in SW
* or HW except by looking into debugfs.
*
* All key management is internally protected by a mutex. Within all
* other parts of mac80211, key references are, just as STA structure
* references, protected by RCU. Note, however, that some things are
* unprotected, namely the key->sta dereferences within the hardware
* acceleration functions. This means that sta_info_destroy() must
* remove the key which waits for an RCU grace period.
*/
static const u8 bcast_addr[ETH_ALEN] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
static void assert_key_lock(struct ieee80211_local *local)
{
lockdep_assert_held(&local->key_mtx);
}
static void increment_tailroom_need_count(struct ieee80211_sub_if_data *sdata)
{
/*
* When this count is zero, SKB resizing for allocating tailroom
* for IV or MMIC is skipped. But, this check has created two race
* cases in xmit path while transiting from zero count to one:
*
* 1. SKB resize was skipped because no key was added but just before
* the xmit key is added and SW encryption kicks off.
*
* 2. SKB resize was skipped because all the keys were hw planted but
* just before xmit one of the key is deleted and SW encryption kicks
* off.
*
* In both the above case SW encryption will find not enough space for
* tailroom and exits with WARN_ON. (See WARN_ONs at wpa.c)
*
* Solution has been explained at
* http://mid.gmane.org/1308590980.4322.19.camel@jlt3.sipsolutions.net
*/
if (!sdata->crypto_tx_tailroom_needed_cnt++) {
/*
* Flush all XMIT packets currently using HW encryption or no
* encryption at all if the count transition is from 0 -> 1.
*/
synchronize_net();
}
}
static int ieee80211_key_enable_hw_accel(struct ieee80211_key *key)
{
struct ieee80211_sub_if_data *sdata;
struct sta_info *sta;
int ret;
might_sleep();
if (!key->local->ops->set_key)
goto out_unsupported;
assert_key_lock(key->local);
sta = key->sta;
/*
* If this is a per-STA GTK, check if it
* is supported; if not, return.
*/
if (sta && !(key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE) &&
!(key->local->hw.flags & IEEE80211_HW_SUPPORTS_PER_STA_GTK))
goto out_unsupported;
if (sta && !sta->uploaded)
goto out_unsupported;
sdata = key->sdata;
if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN) {
/*
* The driver doesn't know anything about VLAN interfaces.
* Hence, don't send GTKs for VLAN interfaces to the driver.
*/
if (!(key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE))
goto out_unsupported;
}
ret = drv_set_key(key->local, SET_KEY, sdata,
sta ? &sta->sta : NULL, &key->conf);
if (!ret) {
key->flags |= KEY_FLAG_UPLOADED_TO_HARDWARE;
if (!((key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC) ||
(key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV) ||
(key->conf.flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)))
sdata->crypto_tx_tailroom_needed_cnt--;
WARN_ON((key->conf.flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE) &&
(key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV));
return 0;
}
if (ret != -ENOSPC && ret != -EOPNOTSUPP)
wiphy_err(key->local->hw.wiphy,
"failed to set key (%d, %pM) to hardware (%d)\n",
key->conf.keyidx,
sta ? sta->sta.addr : bcast_addr, ret);
out_unsupported:
switch (key->conf.cipher) {
case WLAN_CIPHER_SUITE_WEP40:
case WLAN_CIPHER_SUITE_WEP104:
case WLAN_CIPHER_SUITE_TKIP:
case WLAN_CIPHER_SUITE_CCMP:
case WLAN_CIPHER_SUITE_AES_CMAC:
/* all of these we can do in software */
return 0;
default:
return -EINVAL;
}
}
static void ieee80211_key_disable_hw_accel(struct ieee80211_key *key)
{
struct ieee80211_sub_if_data *sdata;
struct sta_info *sta;
int ret;
might_sleep();
if (!key || !key->local->ops->set_key)
return;
assert_key_lock(key->local);
if (!(key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE))
return;
sta = key->sta;
sdata = key->sdata;
if (!((key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC) ||
(key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV) ||
(key->conf.flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)))
increment_tailroom_need_count(sdata);
ret = drv_set_key(key->local, DISABLE_KEY, sdata,
sta ? &sta->sta : NULL, &key->conf);
if (ret)
wiphy_err(key->local->hw.wiphy,
"failed to remove key (%d, %pM) from hardware (%d)\n",
key->conf.keyidx,
sta ? sta->sta.addr : bcast_addr, ret);
key->flags &= ~KEY_FLAG_UPLOADED_TO_HARDWARE;
}
void ieee80211_key_removed(struct ieee80211_key_conf *key_conf)
{
struct ieee80211_key *key;
key = container_of(key_conf, struct ieee80211_key, conf);
might_sleep();
assert_key_lock(key->local);
key->flags &= ~KEY_FLAG_UPLOADED_TO_HARDWARE;
/*
* Flush TX path to avoid attempts to use this key
* after this function returns. Until then, drivers
* must be prepared to handle the key.
*/
synchronize_rcu();
}
EXPORT_SYMBOL_GPL(ieee80211_key_removed);
static void __ieee80211_set_default_key(struct ieee80211_sub_if_data *sdata,
int idx, bool uni, bool multi)
{
struct ieee80211_key *key = NULL;
assert_key_lock(sdata->local);
if (idx >= 0 && idx < NUM_DEFAULT_KEYS)
key = key_mtx_dereference(sdata->local, sdata->keys[idx]);
if (uni)
rcu_assign_pointer(sdata->default_unicast_key, key);
if (multi)
rcu_assign_pointer(sdata->default_multicast_key, key);
ieee80211_debugfs_key_update_default(sdata);
}
void ieee80211_set_default_key(struct ieee80211_sub_if_data *sdata, int idx,
bool uni, bool multi)
{
mutex_lock(&sdata->local->key_mtx);
__ieee80211_set_default_key(sdata, idx, uni, multi);
mutex_unlock(&sdata->local->key_mtx);
}
static void
__ieee80211_set_default_mgmt_key(struct ieee80211_sub_if_data *sdata, int idx)
{
struct ieee80211_key *key = NULL;
assert_key_lock(sdata->local);
if (idx >= NUM_DEFAULT_KEYS &&
idx < NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS)
key = key_mtx_dereference(sdata->local, sdata->keys[idx]);
rcu_assign_pointer(sdata->default_mgmt_key, key);
ieee80211_debugfs_key_update_default(sdata);
}
void ieee80211_set_default_mgmt_key(struct ieee80211_sub_if_data *sdata,
int idx)
{
mutex_lock(&sdata->local->key_mtx);
__ieee80211_set_default_mgmt_key(sdata, idx);
mutex_unlock(&sdata->local->key_mtx);
}
static void __ieee80211_key_replace(struct ieee80211_sub_if_data *sdata,
struct sta_info *sta,
bool pairwise,
struct ieee80211_key *old,
struct ieee80211_key *new)
{
int idx;
bool defunikey, defmultikey, defmgmtkey;
if (new)
list_add_tail(&new->list, &sdata->key_list);
if (sta && pairwise) {
rcu_assign_pointer(sta->ptk, new);
} else if (sta) {
if (old)
idx = old->conf.keyidx;
else
idx = new->conf.keyidx;
rcu_assign_pointer(sta->gtk[idx], new);
} else {
WARN_ON(new && old && new->conf.keyidx != old->conf.keyidx);
if (old)
idx = old->conf.keyidx;
else
idx = new->conf.keyidx;
defunikey = old &&
old == key_mtx_dereference(sdata->local,
sdata->default_unicast_key);
defmultikey = old &&
old == key_mtx_dereference(sdata->local,
sdata->default_multicast_key);
defmgmtkey = old &&
old == key_mtx_dereference(sdata->local,
sdata->default_mgmt_key);
if (defunikey && !new)
__ieee80211_set_default_key(sdata, -1, true, false);
if (defmultikey && !new)
__ieee80211_set_default_key(sdata, -1, false, true);
if (defmgmtkey && !new)
__ieee80211_set_default_mgmt_key(sdata, -1);
rcu_assign_pointer(sdata->keys[idx], new);
if (defunikey && new)
__ieee80211_set_default_key(sdata, new->conf.keyidx,
true, false);
if (defmultikey && new)
__ieee80211_set_default_key(sdata, new->conf.keyidx,
false, true);
if (defmgmtkey && new)
__ieee80211_set_default_mgmt_key(sdata,
new->conf.keyidx);
}
if (old)
list_del(&old->list);
}
struct ieee80211_key *ieee80211_key_alloc(u32 cipher, int idx, size_t key_len,
const u8 *key_data,
size_t seq_len, const u8 *seq)
{
struct ieee80211_key *key;
int i, j, err;
BUG_ON(idx < 0 || idx >= NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS);
key = kzalloc(sizeof(struct ieee80211_key) + key_len, GFP_KERNEL);
if (!key)
return ERR_PTR(-ENOMEM);
/*
* Default to software encryption; we'll later upload the
* key to the hardware if possible.
*/
key->conf.flags = 0;
key->flags = 0;
key->conf.cipher = cipher;
key->conf.keyidx = idx;
key->conf.keylen = key_len;
switch (cipher) {
case WLAN_CIPHER_SUITE_WEP40:
case WLAN_CIPHER_SUITE_WEP104:
key->conf.iv_len = WEP_IV_LEN;
key->conf.icv_len = WEP_ICV_LEN;
break;
case WLAN_CIPHER_SUITE_TKIP:
key->conf.iv_len = TKIP_IV_LEN;
key->conf.icv_len = TKIP_ICV_LEN;
if (seq) {
for (i = 0; i < NUM_RX_DATA_QUEUES; i++) {
key->u.tkip.rx[i].iv32 =
get_unaligned_le32(&seq[2]);
key->u.tkip.rx[i].iv16 =
get_unaligned_le16(seq);
}
}
spin_lock_init(&key->u.tkip.txlock);
break;
case WLAN_CIPHER_SUITE_CCMP:
key->conf.iv_len = CCMP_HDR_LEN;
key->conf.icv_len = CCMP_MIC_LEN;
if (seq) {
for (i = 0; i < NUM_RX_DATA_QUEUES + 1; i++)
for (j = 0; j < CCMP_PN_LEN; j++)
key->u.ccmp.rx_pn[i][j] =
seq[CCMP_PN_LEN - j - 1];
}
/*
* Initialize AES key state here as an optimization so that
* it does not need to be initialized for every packet.
*/
key->u.ccmp.tfm = ieee80211_aes_key_setup_encrypt(key_data);
if (IS_ERR(key->u.ccmp.tfm)) {
err = PTR_ERR(key->u.ccmp.tfm);
kfree(key);
return ERR_PTR(err);
}
break;
case WLAN_CIPHER_SUITE_AES_CMAC:
key->conf.iv_len = 0;
key->conf.icv_len = sizeof(struct ieee80211_mmie);
if (seq)
for (j = 0; j < 6; j++)
key->u.aes_cmac.rx_pn[j] = seq[6 - j - 1];
/*
* Initialize AES key state here as an optimization so that
* it does not need to be initialized for every packet.
*/
key->u.aes_cmac.tfm =
ieee80211_aes_cmac_key_setup(key_data);
if (IS_ERR(key->u.aes_cmac.tfm)) {
err = PTR_ERR(key->u.aes_cmac.tfm);
kfree(key);
return ERR_PTR(err);
}
break;
}
memcpy(key->conf.key, key_data, key_len);
INIT_LIST_HEAD(&key->list);
return key;
}
static void __ieee80211_key_destroy(struct ieee80211_key *key)
{
if (!key)
return;
/*
* Synchronize so the TX path can no longer be using
* this key before we free/remove it.
*/
synchronize_rcu();
if (key->local)
ieee80211_key_disable_hw_accel(key);
if (key->conf.cipher == WLAN_CIPHER_SUITE_CCMP)
ieee80211_aes_key_free(key->u.ccmp.tfm);
if (key->conf.cipher == WLAN_CIPHER_SUITE_AES_CMAC)
ieee80211_aes_cmac_key_free(key->u.aes_cmac.tfm);
if (key->local) {
ieee80211_debugfs_key_remove(key);
key->sdata->crypto_tx_tailroom_needed_cnt--;
}
kfree(key);
}
int ieee80211_key_link(struct ieee80211_key *key,
struct ieee80211_sub_if_data *sdata,
struct sta_info *sta)
{
struct ieee80211_key *old_key;
int idx, ret;
bool pairwise;
BUG_ON(!sdata);
BUG_ON(!key);
pairwise = key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE;
idx = key->conf.keyidx;
key->local = sdata->local;
key->sdata = sdata;
key->sta = sta;
if (sta) {
/*
* some hardware cannot handle TKIP with QoS, so
* we indicate whether QoS could be in use.
*/
if (test_sta_flag(sta, WLAN_STA_WME))
key->conf.flags |= IEEE80211_KEY_FLAG_WMM_STA;
} else {
if (sdata->vif.type == NL80211_IFTYPE_STATION) {
struct sta_info *ap;
/*
* We're getting a sta pointer in, so must be under
* appropriate locking for sta_info_get().
*/
/* same here, the AP could be using QoS */
ap = sta_info_get(key->sdata, key->sdata->u.mgd.bssid);
if (ap) {
if (test_sta_flag(ap, WLAN_STA_WME))
key->conf.flags |=
IEEE80211_KEY_FLAG_WMM_STA;
}
}
}
mutex_lock(&sdata->local->key_mtx);
if (sta && pairwise)
old_key = key_mtx_dereference(sdata->local, sta->ptk);
else if (sta)
old_key = key_mtx_dereference(sdata->local, sta->gtk[idx]);
else
old_key = key_mtx_dereference(sdata->local, sdata->keys[idx]);
increment_tailroom_need_count(sdata);
__ieee80211_key_replace(sdata, sta, pairwise, old_key, key);
__ieee80211_key_destroy(old_key);
ieee80211_debugfs_key_add(key);
ret = ieee80211_key_enable_hw_accel(key);
mutex_unlock(&sdata->local->key_mtx);
return ret;
}
void __ieee80211_key_free(struct ieee80211_key *key)
{
if (!key)
return;
/*
* Replace key with nothingness if it was ever used.
*/
if (key->sdata)
__ieee80211_key_replace(key->sdata, key->sta,
key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE,
key, NULL);
__ieee80211_key_destroy(key);
}
void ieee80211_key_free(struct ieee80211_local *local,
struct ieee80211_key *key)
{
mutex_lock(&local->key_mtx);
__ieee80211_key_free(key);
mutex_unlock(&local->key_mtx);
}
void ieee80211_enable_keys(struct ieee80211_sub_if_data *sdata)
{
struct ieee80211_key *key;
ASSERT_RTNL();
if (WARN_ON(!ieee80211_sdata_running(sdata)))
return;
mutex_lock(&sdata->local->key_mtx);
sdata->crypto_tx_tailroom_needed_cnt = 0;
list_for_each_entry(key, &sdata->key_list, list) {
increment_tailroom_need_count(sdata);
ieee80211_key_enable_hw_accel(key);
}
mutex_unlock(&sdata->local->key_mtx);
}
void ieee80211_iter_keys(struct ieee80211_hw *hw,
struct ieee80211_vif *vif,
void (*iter)(struct ieee80211_hw *hw,
struct ieee80211_vif *vif,
struct ieee80211_sta *sta,
struct ieee80211_key_conf *key,
void *data),
void *iter_data)
{
struct ieee80211_local *local = hw_to_local(hw);
struct ieee80211_key *key;
struct ieee80211_sub_if_data *sdata;
ASSERT_RTNL();
mutex_lock(&local->key_mtx);
if (vif) {
sdata = vif_to_sdata(vif);
list_for_each_entry(key, &sdata->key_list, list)
iter(hw, &sdata->vif,
key->sta ? &key->sta->sta : NULL,
&key->conf, iter_data);
} else {
list_for_each_entry(sdata, &local->interfaces, list)
list_for_each_entry(key, &sdata->key_list, list)
iter(hw, &sdata->vif,
key->sta ? &key->sta->sta : NULL,
&key->conf, iter_data);
}
mutex_unlock(&local->key_mtx);
}
EXPORT_SYMBOL(ieee80211_iter_keys);
void ieee80211_disable_keys(struct ieee80211_sub_if_data *sdata)
{
struct ieee80211_key *key;
ASSERT_RTNL();
mutex_lock(&sdata->local->key_mtx);
list_for_each_entry(key, &sdata->key_list, list)
ieee80211_key_disable_hw_accel(key);
mutex_unlock(&sdata->local->key_mtx);
}
void ieee80211_free_keys(struct ieee80211_sub_if_data *sdata)
{
struct ieee80211_key *key, *tmp;
mutex_lock(&sdata->local->key_mtx);
ieee80211_debugfs_key_remove_mgmt_default(sdata);
list_for_each_entry_safe(key, tmp, &sdata->key_list, list)
__ieee80211_key_free(key);
ieee80211_debugfs_key_update_default(sdata);
mutex_unlock(&sdata->local->key_mtx);
}
void ieee80211_gtk_rekey_notify(struct ieee80211_vif *vif, const u8 *bssid,
const u8 *replay_ctr, gfp_t gfp)
{
struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
trace_api_gtk_rekey_notify(sdata, bssid, replay_ctr);
cfg80211_gtk_rekey_notify(sdata->dev, bssid, replay_ctr, gfp);
}
EXPORT_SYMBOL_GPL(ieee80211_gtk_rekey_notify);
void ieee80211_get_key_tx_seq(struct ieee80211_key_conf *keyconf,
struct ieee80211_key_seq *seq)
{
struct ieee80211_key *key;
u64 pn64;
if (WARN_ON(!(keyconf->flags & IEEE80211_KEY_FLAG_GENERATE_IV)))
return;
key = container_of(keyconf, struct ieee80211_key, conf);
switch (key->conf.cipher) {
case WLAN_CIPHER_SUITE_TKIP:
seq->tkip.iv32 = key->u.tkip.tx.iv32;
seq->tkip.iv16 = key->u.tkip.tx.iv16;
break;
case WLAN_CIPHER_SUITE_CCMP:
pn64 = atomic64_read(&key->u.ccmp.tx_pn);
seq->ccmp.pn[5] = pn64;
seq->ccmp.pn[4] = pn64 >> 8;
seq->ccmp.pn[3] = pn64 >> 16;
seq->ccmp.pn[2] = pn64 >> 24;
seq->ccmp.pn[1] = pn64 >> 32;
seq->ccmp.pn[0] = pn64 >> 40;
break;
case WLAN_CIPHER_SUITE_AES_CMAC:
pn64 = atomic64_read(&key->u.aes_cmac.tx_pn);
seq->ccmp.pn[5] = pn64;
seq->ccmp.pn[4] = pn64 >> 8;
seq->ccmp.pn[3] = pn64 >> 16;
seq->ccmp.pn[2] = pn64 >> 24;
seq->ccmp.pn[1] = pn64 >> 32;
seq->ccmp.pn[0] = pn64 >> 40;
break;
default:
WARN_ON(1);
}
}
EXPORT_SYMBOL(ieee80211_get_key_tx_seq);
void ieee80211_get_key_rx_seq(struct ieee80211_key_conf *keyconf,
int tid, struct ieee80211_key_seq *seq)
{
struct ieee80211_key *key;
const u8 *pn;
key = container_of(keyconf, struct ieee80211_key, conf);
switch (key->conf.cipher) {
case WLAN_CIPHER_SUITE_TKIP:
if (WARN_ON(tid < 0 || tid >= NUM_RX_DATA_QUEUES))
return;
seq->tkip.iv32 = key->u.tkip.rx[tid].iv32;
seq->tkip.iv16 = key->u.tkip.rx[tid].iv16;
break;
case WLAN_CIPHER_SUITE_CCMP:
if (WARN_ON(tid < -1 || tid >= NUM_RX_DATA_QUEUES))
return;
if (tid < 0)
pn = key->u.ccmp.rx_pn[NUM_RX_DATA_QUEUES];
else
pn = key->u.ccmp.rx_pn[tid];
memcpy(seq->ccmp.pn, pn, CCMP_PN_LEN);
break;
case WLAN_CIPHER_SUITE_AES_CMAC:
if (WARN_ON(tid != 0))
return;
pn = key->u.aes_cmac.rx_pn;
memcpy(seq->aes_cmac.pn, pn, CMAC_PN_LEN);
break;
}
}
EXPORT_SYMBOL(ieee80211_get_key_rx_seq);