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key.c
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// SPDX-License-Identifier: GPL-2.0-only
/*
* 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>
* Copyright 2013-2014 Intel Mobile Communications GmbH
* Copyright 2015-2017 Intel Deutschland GmbH
* Copyright 2018-2020, 2022 Intel Corporation
*/
#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 <crypto/algapi.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"
#include "aes_gmac.h"
#include "aes_gcm.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
update_vlan_tailroom_need_count(struct ieee80211_sub_if_data *sdata, int delta)
{
struct ieee80211_sub_if_data *vlan;
if (sdata->vif.type != NL80211_IFTYPE_AP)
return;
/* crypto_tx_tailroom_needed_cnt is protected by this */
assert_key_lock(sdata->local);
rcu_read_lock();
list_for_each_entry_rcu(vlan, &sdata->u.ap.vlans, u.vlan.list)
vlan->crypto_tx_tailroom_needed_cnt += delta;
rcu_read_unlock();
}
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
*/
assert_key_lock(sdata->local);
update_vlan_tailroom_need_count(sdata, 1);
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 void decrease_tailroom_need_count(struct ieee80211_sub_if_data *sdata,
int delta)
{
assert_key_lock(sdata->local);
WARN_ON_ONCE(sdata->crypto_tx_tailroom_needed_cnt < delta);
update_vlan_tailroom_need_count(sdata, -delta);
sdata->crypto_tx_tailroom_needed_cnt -= delta;
}
static int ieee80211_key_enable_hw_accel(struct ieee80211_key *key)
{
struct ieee80211_sub_if_data *sdata = key->sdata;
struct sta_info *sta;
int ret = -EOPNOTSUPP;
might_sleep();
if (key->flags & KEY_FLAG_TAINTED) {
/* If we get here, it's during resume and the key is
* tainted so shouldn't be used/programmed any more.
* However, its flags may still indicate that it was
* programmed into the device (since we're in resume)
* so clear that flag now to avoid trying to remove
* it again later.
*/
if (key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE &&
!(key->conf.flags & (IEEE80211_KEY_FLAG_GENERATE_MMIC |
IEEE80211_KEY_FLAG_PUT_MIC_SPACE |
IEEE80211_KEY_FLAG_RESERVE_TAILROOM)))
increment_tailroom_need_count(sdata);
key->flags &= ~KEY_FLAG_UPLOADED_TO_HARDWARE;
return -EINVAL;
}
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) &&
!ieee80211_hw_check(&key->local->hw, SUPPORTS_PER_STA_GTK))
goto out_unsupported;
if (sta && !sta->uploaded)
goto out_unsupported;
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)) {
ret = 1;
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 |
IEEE80211_KEY_FLAG_PUT_MIC_SPACE |
IEEE80211_KEY_FLAG_RESERVE_TAILROOM)))
decrease_tailroom_need_count(sdata, 1);
WARN_ON((key->conf.flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE) &&
(key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV));
WARN_ON((key->conf.flags & IEEE80211_KEY_FLAG_PUT_MIC_SPACE) &&
(key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC));
return 0;
}
if (ret != -ENOSPC && ret != -EOPNOTSUPP && ret != 1)
sdata_err(sdata,
"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_CCMP_256:
case WLAN_CIPHER_SUITE_GCMP:
case WLAN_CIPHER_SUITE_GCMP_256:
case WLAN_CIPHER_SUITE_AES_CMAC:
case WLAN_CIPHER_SUITE_BIP_CMAC_256:
case WLAN_CIPHER_SUITE_BIP_GMAC_128:
case WLAN_CIPHER_SUITE_BIP_GMAC_256:
/* all of these we can do in software - if driver can */
if (ret == 1)
return 0;
if (ieee80211_hw_check(&key->local->hw, SW_CRYPTO_CONTROL))
return -EINVAL;
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 |
IEEE80211_KEY_FLAG_PUT_MIC_SPACE |
IEEE80211_KEY_FLAG_RESERVE_TAILROOM)))
increment_tailroom_need_count(sdata);
key->flags &= ~KEY_FLAG_UPLOADED_TO_HARDWARE;
ret = drv_set_key(key->local, DISABLE_KEY, sdata,
sta ? &sta->sta : NULL, &key->conf);
if (ret)
sdata_err(sdata,
"failed to remove key (%d, %pM) from hardware (%d)\n",
key->conf.keyidx,
sta ? sta->sta.addr : bcast_addr, ret);
}
static int _ieee80211_set_tx_key(struct ieee80211_key *key, bool force)
{
struct sta_info *sta = key->sta;
struct ieee80211_local *local = key->local;
assert_key_lock(local);
set_sta_flag(sta, WLAN_STA_USES_ENCRYPTION);
sta->ptk_idx = key->conf.keyidx;
if (force || !ieee80211_hw_check(&local->hw, AMPDU_KEYBORDER_SUPPORT))
clear_sta_flag(sta, WLAN_STA_BLOCK_BA);
ieee80211_check_fast_xmit(sta);
return 0;
}
int ieee80211_set_tx_key(struct ieee80211_key *key)
{
return _ieee80211_set_tx_key(key, false);
}
static void ieee80211_pairwise_rekey(struct ieee80211_key *old,
struct ieee80211_key *new)
{
struct ieee80211_local *local = new->local;
struct sta_info *sta = new->sta;
int i;
assert_key_lock(local);
if (new->conf.flags & IEEE80211_KEY_FLAG_NO_AUTO_TX) {
/* Extended Key ID key install, initial one or rekey */
if (sta->ptk_idx != INVALID_PTK_KEYIDX &&
!ieee80211_hw_check(&local->hw, AMPDU_KEYBORDER_SUPPORT)) {
/* Aggregation Sessions with Extended Key ID must not
* mix MPDUs with different keyIDs within one A-MPDU.
* Tear down running Tx aggregation sessions and block
* new Rx/Tx aggregation requests during rekey to
* ensure there are no A-MPDUs when the driver is not
* supporting A-MPDU key borders. (Blocking Tx only
* would be sufficient but WLAN_STA_BLOCK_BA gets the
* job done for the few ms we need it.)
*/
set_sta_flag(sta, WLAN_STA_BLOCK_BA);
mutex_lock(&sta->ampdu_mlme.mtx);
for (i = 0; i < IEEE80211_NUM_TIDS; i++)
___ieee80211_stop_tx_ba_session(sta, i,
AGG_STOP_LOCAL_REQUEST);
mutex_unlock(&sta->ampdu_mlme.mtx);
}
} else if (old) {
/* Rekey without Extended Key ID.
* Aggregation sessions are OK when running on SW crypto.
* A broken remote STA may cause issues not observed with HW
* crypto, though.
*/
if (!(old->flags & KEY_FLAG_UPLOADED_TO_HARDWARE))
return;
/* Stop Tx till we are on the new key */
old->flags |= KEY_FLAG_TAINTED;
ieee80211_clear_fast_xmit(sta);
if (ieee80211_hw_check(&local->hw, AMPDU_AGGREGATION)) {
set_sta_flag(sta, WLAN_STA_BLOCK_BA);
ieee80211_sta_tear_down_BA_sessions(sta,
AGG_STOP_LOCAL_REQUEST);
}
if (!wiphy_ext_feature_isset(local->hw.wiphy,
NL80211_EXT_FEATURE_CAN_REPLACE_PTK0)) {
pr_warn_ratelimited("Rekeying PTK for STA %pM but driver can't safely do that.",
sta->sta.addr);
/* Flushing the driver queues *may* help prevent
* the clear text leaks and freezes.
*/
ieee80211_flush_queues(local, old->sdata, false);
}
}
}
static void __ieee80211_set_default_key(struct ieee80211_link_data *link,
int idx, bool uni, bool multi)
{
struct ieee80211_sub_if_data *sdata = link->sdata;
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 (!key)
key = key_mtx_dereference(sdata->local, link->gtk[idx]);
}
if (uni) {
rcu_assign_pointer(sdata->default_unicast_key, key);
ieee80211_check_fast_xmit_iface(sdata);
if (sdata->vif.type != NL80211_IFTYPE_AP_VLAN)
drv_set_default_unicast_key(sdata->local, sdata, idx);
}
if (multi)
rcu_assign_pointer(link->default_multicast_key, key);
ieee80211_debugfs_key_update_default(sdata);
}
void ieee80211_set_default_key(struct ieee80211_link_data *link, int idx,
bool uni, bool multi)
{
mutex_lock(&link->sdata->local->key_mtx);
__ieee80211_set_default_key(link, idx, uni, multi);
mutex_unlock(&link->sdata->local->key_mtx);
}
static void
__ieee80211_set_default_mgmt_key(struct ieee80211_link_data *link, int idx)
{
struct ieee80211_sub_if_data *sdata = link->sdata;
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, link->gtk[idx]);
rcu_assign_pointer(link->default_mgmt_key, key);
ieee80211_debugfs_key_update_default(sdata);
}
void ieee80211_set_default_mgmt_key(struct ieee80211_link_data *link,
int idx)
{
mutex_lock(&link->sdata->local->key_mtx);
__ieee80211_set_default_mgmt_key(link, idx);
mutex_unlock(&link->sdata->local->key_mtx);
}
static void
__ieee80211_set_default_beacon_key(struct ieee80211_link_data *link, int idx)
{
struct ieee80211_sub_if_data *sdata = link->sdata;
struct ieee80211_key *key = NULL;
assert_key_lock(sdata->local);
if (idx >= NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS &&
idx < NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS +
NUM_DEFAULT_BEACON_KEYS)
key = key_mtx_dereference(sdata->local, link->gtk[idx]);
rcu_assign_pointer(link->default_beacon_key, key);
ieee80211_debugfs_key_update_default(sdata);
}
void ieee80211_set_default_beacon_key(struct ieee80211_link_data *link,
int idx)
{
mutex_lock(&link->sdata->local->key_mtx);
__ieee80211_set_default_beacon_key(link, idx);
mutex_unlock(&link->sdata->local->key_mtx);
}
static int ieee80211_key_replace(struct ieee80211_sub_if_data *sdata,
struct ieee80211_link_data *link,
struct sta_info *sta,
bool pairwise,
struct ieee80211_key *old,
struct ieee80211_key *new)
{
struct link_sta_info *link_sta = sta ? &sta->deflink : NULL;
int link_id;
int idx;
int ret = 0;
bool defunikey, defmultikey, defmgmtkey, defbeaconkey;
bool is_wep;
/* caller must provide at least one old/new */
if (WARN_ON(!new && !old))
return 0;
if (new) {
idx = new->conf.keyidx;
is_wep = new->conf.cipher == WLAN_CIPHER_SUITE_WEP40 ||
new->conf.cipher == WLAN_CIPHER_SUITE_WEP104;
link_id = new->conf.link_id;
} else {
idx = old->conf.keyidx;
is_wep = old->conf.cipher == WLAN_CIPHER_SUITE_WEP40 ||
old->conf.cipher == WLAN_CIPHER_SUITE_WEP104;
link_id = old->conf.link_id;
}
if (WARN(old && old->conf.link_id != link_id,
"old link ID %d doesn't match new link ID %d\n",
old->conf.link_id, link_id))
return -EINVAL;
if (link_id >= 0) {
if (!link) {
link = sdata_dereference(sdata->link[link_id], sdata);
if (!link)
return -ENOLINK;
}
if (sta) {
link_sta = rcu_dereference_protected(sta->link[link_id],
lockdep_is_held(&sta->local->sta_mtx));
if (!link_sta)
return -ENOLINK;
}
} else {
link = &sdata->deflink;
}
if ((is_wep || pairwise) && idx >= NUM_DEFAULT_KEYS)
return -EINVAL;
WARN_ON(new && old && new->conf.keyidx != old->conf.keyidx);
if (new && sta && pairwise) {
/* Unicast rekey needs special handling. With Extended Key ID
* old is still NULL for the first rekey.
*/
ieee80211_pairwise_rekey(old, new);
}
if (old) {
if (old->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) {
ieee80211_key_disable_hw_accel(old);
if (new)
ret = ieee80211_key_enable_hw_accel(new);
}
} else {
if (!new->local->wowlan)
ret = ieee80211_key_enable_hw_accel(new);
}
if (ret)
return ret;
if (new)
list_add_tail_rcu(&new->list, &sdata->key_list);
if (sta) {
if (pairwise) {
rcu_assign_pointer(sta->ptk[idx], new);
if (new &&
!(new->conf.flags & IEEE80211_KEY_FLAG_NO_AUTO_TX))
_ieee80211_set_tx_key(new, true);
} else {
rcu_assign_pointer(link_sta->gtk[idx], new);
}
/* Only needed for transition from no key -> key.
* Still triggers unnecessary when using Extended Key ID
* and installing the second key ID the first time.
*/
if (new && !old)
ieee80211_check_fast_rx(sta);
} else {
defunikey = old &&
old == key_mtx_dereference(sdata->local,
sdata->default_unicast_key);
defmultikey = old &&
old == key_mtx_dereference(sdata->local,
link->default_multicast_key);
defmgmtkey = old &&
old == key_mtx_dereference(sdata->local,
link->default_mgmt_key);
defbeaconkey = old &&
old == key_mtx_dereference(sdata->local,
link->default_beacon_key);
if (defunikey && !new)
__ieee80211_set_default_key(link, -1, true, false);
if (defmultikey && !new)
__ieee80211_set_default_key(link, -1, false, true);
if (defmgmtkey && !new)
__ieee80211_set_default_mgmt_key(link, -1);
if (defbeaconkey && !new)
__ieee80211_set_default_beacon_key(link, -1);
if (is_wep || pairwise)
rcu_assign_pointer(sdata->keys[idx], new);
else
rcu_assign_pointer(link->gtk[idx], new);
if (defunikey && new)
__ieee80211_set_default_key(link, new->conf.keyidx,
true, false);
if (defmultikey && new)
__ieee80211_set_default_key(link, new->conf.keyidx,
false, true);
if (defmgmtkey && new)
__ieee80211_set_default_mgmt_key(link,
new->conf.keyidx);
if (defbeaconkey && new)
__ieee80211_set_default_beacon_key(link,
new->conf.keyidx);
}
if (old)
list_del_rcu(&old->list);
return 0;
}
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;
if (WARN_ON(idx < 0 ||
idx >= NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS +
NUM_DEFAULT_BEACON_KEYS))
return ERR_PTR(-EINVAL);
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.link_id = -1;
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 = IEEE80211_WEP_IV_LEN;
key->conf.icv_len = IEEE80211_WEP_ICV_LEN;
break;
case WLAN_CIPHER_SUITE_TKIP:
key->conf.iv_len = IEEE80211_TKIP_IV_LEN;
key->conf.icv_len = IEEE80211_TKIP_ICV_LEN;
if (seq) {
for (i = 0; i < IEEE80211_NUM_TIDS; 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 = IEEE80211_CCMP_HDR_LEN;
key->conf.icv_len = IEEE80211_CCMP_MIC_LEN;
if (seq) {
for (i = 0; i < IEEE80211_NUM_TIDS + 1; i++)
for (j = 0; j < IEEE80211_CCMP_PN_LEN; j++)
key->u.ccmp.rx_pn[i][j] =
seq[IEEE80211_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, key_len, IEEE80211_CCMP_MIC_LEN);
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_CCMP_256:
key->conf.iv_len = IEEE80211_CCMP_256_HDR_LEN;
key->conf.icv_len = IEEE80211_CCMP_256_MIC_LEN;
for (i = 0; seq && i < IEEE80211_NUM_TIDS + 1; i++)
for (j = 0; j < IEEE80211_CCMP_256_PN_LEN; j++)
key->u.ccmp.rx_pn[i][j] =
seq[IEEE80211_CCMP_256_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, key_len, IEEE80211_CCMP_256_MIC_LEN);
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:
case WLAN_CIPHER_SUITE_BIP_CMAC_256:
key->conf.iv_len = 0;
if (cipher == WLAN_CIPHER_SUITE_AES_CMAC)
key->conf.icv_len = sizeof(struct ieee80211_mmie);
else
key->conf.icv_len = sizeof(struct ieee80211_mmie_16);
if (seq)
for (j = 0; j < IEEE80211_CMAC_PN_LEN; j++)
key->u.aes_cmac.rx_pn[j] =
seq[IEEE80211_CMAC_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.aes_cmac.tfm =
ieee80211_aes_cmac_key_setup(key_data, key_len);
if (IS_ERR(key->u.aes_cmac.tfm)) {
err = PTR_ERR(key->u.aes_cmac.tfm);
kfree(key);
return ERR_PTR(err);
}
break;
case WLAN_CIPHER_SUITE_BIP_GMAC_128:
case WLAN_CIPHER_SUITE_BIP_GMAC_256:
key->conf.iv_len = 0;
key->conf.icv_len = sizeof(struct ieee80211_mmie_16);
if (seq)
for (j = 0; j < IEEE80211_GMAC_PN_LEN; j++)
key->u.aes_gmac.rx_pn[j] =
seq[IEEE80211_GMAC_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.aes_gmac.tfm =
ieee80211_aes_gmac_key_setup(key_data, key_len);
if (IS_ERR(key->u.aes_gmac.tfm)) {
err = PTR_ERR(key->u.aes_gmac.tfm);
kfree(key);
return ERR_PTR(err);
}
break;
case WLAN_CIPHER_SUITE_GCMP:
case WLAN_CIPHER_SUITE_GCMP_256:
key->conf.iv_len = IEEE80211_GCMP_HDR_LEN;
key->conf.icv_len = IEEE80211_GCMP_MIC_LEN;
for (i = 0; seq && i < IEEE80211_NUM_TIDS + 1; i++)
for (j = 0; j < IEEE80211_GCMP_PN_LEN; j++)
key->u.gcmp.rx_pn[i][j] =
seq[IEEE80211_GCMP_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.gcmp.tfm = ieee80211_aes_gcm_key_setup_encrypt(key_data,
key_len);
if (IS_ERR(key->u.gcmp.tfm)) {
err = PTR_ERR(key->u.gcmp.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_free_common(struct ieee80211_key *key)
{
switch (key->conf.cipher) {
case WLAN_CIPHER_SUITE_CCMP:
case WLAN_CIPHER_SUITE_CCMP_256:
ieee80211_aes_key_free(key->u.ccmp.tfm);
break;
case WLAN_CIPHER_SUITE_AES_CMAC:
case WLAN_CIPHER_SUITE_BIP_CMAC_256:
ieee80211_aes_cmac_key_free(key->u.aes_cmac.tfm);
break;
case WLAN_CIPHER_SUITE_BIP_GMAC_128:
case WLAN_CIPHER_SUITE_BIP_GMAC_256:
ieee80211_aes_gmac_key_free(key->u.aes_gmac.tfm);
break;
case WLAN_CIPHER_SUITE_GCMP:
case WLAN_CIPHER_SUITE_GCMP_256:
ieee80211_aes_gcm_key_free(key->u.gcmp.tfm);
break;
}
kfree_sensitive(key);
}
static void __ieee80211_key_destroy(struct ieee80211_key *key,
bool delay_tailroom)
{
if (key->local) {
struct ieee80211_sub_if_data *sdata = key->sdata;
ieee80211_debugfs_key_remove(key);
if (delay_tailroom) {
/* see ieee80211_delayed_tailroom_dec */
sdata->crypto_tx_tailroom_pending_dec++;
schedule_delayed_work(&sdata->dec_tailroom_needed_wk,
HZ/2);
} else {
decrease_tailroom_need_count(sdata, 1);
}
}
ieee80211_key_free_common(key);
}
static void ieee80211_key_destroy(struct ieee80211_key *key,
bool delay_tailroom)
{
if (!key)
return;
/*
* Synchronize so the TX path and rcu key iterators
* can no longer be using this key before we free/remove it.
*/
synchronize_net();
__ieee80211_key_destroy(key, delay_tailroom);
}
void ieee80211_key_free_unused(struct ieee80211_key *key)
{
WARN_ON(key->sdata || key->local);
ieee80211_key_free_common(key);
}
static bool ieee80211_key_identical(struct ieee80211_sub_if_data *sdata,
struct ieee80211_key *old,
struct ieee80211_key *new)
{
u8 tkip_old[WLAN_KEY_LEN_TKIP], tkip_new[WLAN_KEY_LEN_TKIP];
u8 *tk_old, *tk_new;
if (!old || new->conf.keylen != old->conf.keylen)
return false;
tk_old = old->conf.key;
tk_new = new->conf.key;
/*
* In station mode, don't compare the TX MIC key, as it's never used
* and offloaded rekeying may not care to send it to the host. This
* is the case in iwlwifi, for example.
*/
if (sdata->vif.type == NL80211_IFTYPE_STATION &&
new->conf.cipher == WLAN_CIPHER_SUITE_TKIP &&
new->conf.keylen == WLAN_KEY_LEN_TKIP &&
!(new->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE)) {
memcpy(tkip_old, tk_old, WLAN_KEY_LEN_TKIP);
memcpy(tkip_new, tk_new, WLAN_KEY_LEN_TKIP);
memset(tkip_old + NL80211_TKIP_DATA_OFFSET_TX_MIC_KEY, 0, 8);
memset(tkip_new + NL80211_TKIP_DATA_OFFSET_TX_MIC_KEY, 0, 8);
tk_old = tkip_old;
tk_new = tkip_new;
}
return !crypto_memneq(tk_old, tk_new, new->conf.keylen);
}
int ieee80211_key_link(struct ieee80211_key *key,
struct ieee80211_link_data *link,
struct sta_info *sta)
{
struct ieee80211_sub_if_data *sdata = link->sdata;
static atomic_t key_color = ATOMIC_INIT(0);
struct ieee80211_key *old_key = NULL;
int idx = key->conf.keyidx;
bool pairwise = key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE;
/*
* We want to delay tailroom updates only for station - in that
* case it helps roaming speed, but in other cases it hurts and
* can cause warnings to appear.
*/
bool delay_tailroom = sdata->vif.type == NL80211_IFTYPE_STATION;
int ret = -EOPNOTSUPP;
mutex_lock(&sdata->local->key_mtx);
if (sta && pairwise) {
struct ieee80211_key *alt_key;
old_key = key_mtx_dereference(sdata->local, sta->ptk[idx]);
alt_key = key_mtx_dereference(sdata->local, sta->ptk[idx ^ 1]);
/* The rekey code assumes that the old and new key are using
* the same cipher. Enforce the assumption for pairwise keys.
*/
if ((alt_key && alt_key->conf.cipher != key->conf.cipher) ||
(old_key && old_key->conf.cipher != key->conf.cipher))
goto out;
} else if (sta) {
struct link_sta_info *link_sta = &sta->deflink;
int link_id = key->conf.link_id;
if (link_id >= 0) {
link_sta = rcu_dereference_protected(sta->link[link_id],
lockdep_is_held(&sta->local->sta_mtx));
if (!link_sta)
return -ENOLINK;
}
old_key = key_mtx_dereference(sdata->local, link_sta->gtk[idx]);
} else {
if (idx < NUM_DEFAULT_KEYS)
old_key = key_mtx_dereference(sdata->local,
sdata->keys[idx]);
if (!old_key)
old_key = key_mtx_dereference(sdata->local,
link->gtk[idx]);
}
/* Non-pairwise keys must also not switch the cipher on rekey */
if (!pairwise) {
if (old_key && old_key->conf.cipher != key->conf.cipher)
goto out;
}
/*
* Silently accept key re-installation without really installing the
* new version of the key to avoid nonce reuse or replay issues.
*/
if (ieee80211_key_identical(sdata, old_key, key)) {
ieee80211_key_free_unused(key);
ret = 0;
goto out;
}
key->local = sdata->local;
key->sdata = sdata;
key->sta = sta;
/*
* Assign a unique ID to every key so we can easily prevent mixed
* key and fragment cache attacks.
*/
key->color = atomic_inc_return(&key_color);
increment_tailroom_need_count(sdata);
ret = ieee80211_key_replace(sdata, link, sta, pairwise, old_key, key);
if (!ret) {
ieee80211_debugfs_key_add(key);
ieee80211_key_destroy(old_key, delay_tailroom);
} else {
ieee80211_key_free(key, delay_tailroom);
}
out:
mutex_unlock(&sdata->local->key_mtx);
return ret;
}
void ieee80211_key_free(struct ieee80211_key *key, bool delay_tailroom)
{
if (!key)
return;
/*
* Replace key with nothingness if it was ever used.
*/
if (key->sdata)
ieee80211_key_replace(key->sdata, NULL, key->sta,
key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE,
key, NULL);
ieee80211_key_destroy(key, delay_tailroom);
}
void ieee80211_reenable_keys(struct ieee80211_sub_if_data *sdata)
{
struct ieee80211_key *key;
struct ieee80211_sub_if_data *vlan;
lockdep_assert_wiphy(sdata->local->hw.wiphy);
mutex_lock(&sdata->local->key_mtx);
sdata->crypto_tx_tailroom_needed_cnt = 0;
sdata->crypto_tx_tailroom_pending_dec = 0;
if (sdata->vif.type == NL80211_IFTYPE_AP) {
list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list) {
vlan->crypto_tx_tailroom_needed_cnt = 0;
vlan->crypto_tx_tailroom_pending_dec = 0;
}
}
if (ieee80211_sdata_running(sdata)) {
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, *tmp;
struct ieee80211_sub_if_data *sdata;
lockdep_assert_wiphy(hw->wiphy);
mutex_lock(&local->key_mtx);
if (vif) {
sdata = vif_to_sdata(vif);
list_for_each_entry_safe(key, tmp, &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_safe(key, tmp,
&sdata->key_list, list)
iter(hw, &sdata->vif,
key->sta ? &key->sta->sta : NULL,
&key->conf, iter_data);
}
mutex_unlock(&local->key_mtx);
}