- 根目录:
- net
- mac80211
- key.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 <net/mac80211.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 struct ieee80211_sta *get_sta_for_key(struct ieee80211_key *key)
{
if (key->sta)
return &key->sta->sta;
return NULL;
}
static int ieee80211_key_enable_hw_accel(struct ieee80211_key *key)
{
struct ieee80211_sub_if_data *sdata;
struct ieee80211_sta *sta;
int ret;
might_sleep();
if (!key->local->ops->set_key)
goto out_unsupported;
assert_key_lock(key->local);
sta = get_sta_for_key(key);
/*
* 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;
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;
sdata = container_of(sdata->bss,
struct ieee80211_sub_if_data,
u.ap);
}
ret = drv_set_key(key->local, SET_KEY, sdata, sta, &key->conf);
if (!ret) {
key->flags |= KEY_FLAG_UPLOADED_TO_HARDWARE;
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->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 ieee80211_sta *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 = get_sta_for_key(key);
sdata = key->sdata;
if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
sdata = container_of(sdata->bss,
struct ieee80211_sub_if_data,
u.ap);
ret = drv_set_key(key->local, DISABLE_KEY, sdata,
sta, &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->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(&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);
}
}
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);
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_flags(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_flags(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]);
__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);
list_for_each_entry(key, &sdata->key_list, list)
ieee80211_key_enable_hw_accel(key);
mutex_unlock(&sdata->local->key_mtx);
}
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);
}