mac80211: 802.11w - Use BIP (AES-128-CMAC)
Add mechanism for managing BIP keys (IGTK) and integrate BIP into the
TX/RX paths.
Signed-off-by: Jouni Malinen <j@w1.fi>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 309d918..72c1069 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -133,6 +133,9 @@
case WLAN_CIPHER_SUITE_CCMP:
alg = ALG_CCMP;
break;
+ case WLAN_CIPHER_SUITE_AES_CMAC:
+ alg = ALG_AES_CMAC;
+ break;
default:
return -EINVAL;
}
@@ -275,6 +278,17 @@
else
params.cipher = WLAN_CIPHER_SUITE_WEP104;
break;
+ case ALG_AES_CMAC:
+ params.cipher = WLAN_CIPHER_SUITE_AES_CMAC;
+ seq[0] = key->u.aes_cmac.tx_pn[5];
+ seq[1] = key->u.aes_cmac.tx_pn[4];
+ seq[2] = key->u.aes_cmac.tx_pn[3];
+ seq[3] = key->u.aes_cmac.tx_pn[2];
+ seq[4] = key->u.aes_cmac.tx_pn[1];
+ seq[5] = key->u.aes_cmac.tx_pn[0];
+ params.seq = seq;
+ params.seq_len = 6;
+ break;
}
params.key = key->conf.key;
@@ -304,6 +318,22 @@
return 0;
}
+static int ieee80211_config_default_mgmt_key(struct wiphy *wiphy,
+ struct net_device *dev,
+ u8 key_idx)
+{
+ struct ieee80211_sub_if_data *sdata;
+
+ rcu_read_lock();
+
+ sdata = IEEE80211_DEV_TO_SUB_IF(dev);
+ ieee80211_set_default_mgmt_key(sdata, key_idx);
+
+ rcu_read_unlock();
+
+ return 0;
+}
+
static void sta_set_sinfo(struct sta_info *sta, struct station_info *sinfo)
{
struct ieee80211_sub_if_data *sdata = sta->sdata;
@@ -1153,6 +1183,7 @@
.del_key = ieee80211_del_key,
.get_key = ieee80211_get_key,
.set_default_key = ieee80211_config_default_key,
+ .set_default_mgmt_key = ieee80211_config_default_mgmt_key,
.add_beacon = ieee80211_add_beacon,
.set_beacon = ieee80211_set_beacon,
.del_beacon = ieee80211_del_beacon,
diff --git a/net/mac80211/debugfs_key.c b/net/mac80211/debugfs_key.c
index 6424ac5..99c7525 100644
--- a/net/mac80211/debugfs_key.c
+++ b/net/mac80211/debugfs_key.c
@@ -76,6 +76,9 @@
case ALG_CCMP:
alg = "CCMP\n";
break;
+ case ALG_AES_CMAC:
+ alg = "AES-128-CMAC\n";
+ break;
default:
return 0;
}
@@ -105,6 +108,12 @@
len = scnprintf(buf, sizeof(buf), "%02x%02x%02x%02x%02x%02x\n",
tpn[0], tpn[1], tpn[2], tpn[3], tpn[4], tpn[5]);
break;
+ case ALG_AES_CMAC:
+ tpn = key->u.aes_cmac.tx_pn;
+ len = scnprintf(buf, sizeof(buf), "%02x%02x%02x%02x%02x%02x\n",
+ tpn[0], tpn[1], tpn[2], tpn[3], tpn[4],
+ tpn[5]);
+ break;
default:
return 0;
}
@@ -142,6 +151,14 @@
}
len = p - buf;
break;
+ case ALG_AES_CMAC:
+ rpn = key->u.aes_cmac.rx_pn;
+ p += scnprintf(p, sizeof(buf)+buf-p,
+ "%02x%02x%02x%02x%02x%02x\n",
+ rpn[0], rpn[1], rpn[2],
+ rpn[3], rpn[4], rpn[5]);
+ len = p - buf;
+ break;
default:
return 0;
}
@@ -156,13 +173,40 @@
char buf[20];
int len;
- if (key->conf.alg != ALG_CCMP)
+ switch (key->conf.alg) {
+ case ALG_CCMP:
+ len = scnprintf(buf, sizeof(buf), "%u\n", key->u.ccmp.replays);
+ break;
+ case ALG_AES_CMAC:
+ len = scnprintf(buf, sizeof(buf), "%u\n",
+ key->u.aes_cmac.replays);
+ break;
+ default:
return 0;
- len = scnprintf(buf, sizeof(buf), "%u\n", key->u.ccmp.replays);
+ }
return simple_read_from_buffer(userbuf, count, ppos, buf, len);
}
KEY_OPS(replays);
+static ssize_t key_icverrors_read(struct file *file, char __user *userbuf,
+ size_t count, loff_t *ppos)
+{
+ struct ieee80211_key *key = file->private_data;
+ char buf[20];
+ int len;
+
+ switch (key->conf.alg) {
+ case ALG_AES_CMAC:
+ len = scnprintf(buf, sizeof(buf), "%u\n",
+ key->u.aes_cmac.icverrors);
+ break;
+ default:
+ return 0;
+ }
+ return simple_read_from_buffer(userbuf, count, ppos, buf, len);
+}
+KEY_OPS(icverrors);
+
static ssize_t key_key_read(struct file *file, char __user *userbuf,
size_t count, loff_t *ppos)
{
@@ -222,6 +266,7 @@
DEBUGFS_ADD(tx_spec);
DEBUGFS_ADD(rx_spec);
DEBUGFS_ADD(replays);
+ DEBUGFS_ADD(icverrors);
DEBUGFS_ADD(key);
DEBUGFS_ADD(ifindex);
};
@@ -243,6 +288,7 @@
DEBUGFS_DEL(tx_spec);
DEBUGFS_DEL(rx_spec);
DEBUGFS_DEL(replays);
+ DEBUGFS_DEL(icverrors);
DEBUGFS_DEL(key);
DEBUGFS_DEL(ifindex);
@@ -280,6 +326,35 @@
sdata->common_debugfs.default_key = NULL;
}
+void ieee80211_debugfs_key_add_mgmt_default(struct ieee80211_sub_if_data *sdata)
+{
+ char buf[50];
+ struct ieee80211_key *key;
+
+ if (!sdata->debugfsdir)
+ return;
+
+ /* this is running under the key lock */
+
+ key = sdata->default_mgmt_key;
+ if (key) {
+ sprintf(buf, "../keys/%d", key->debugfs.cnt);
+ sdata->common_debugfs.default_mgmt_key =
+ debugfs_create_symlink("default_mgmt_key",
+ sdata->debugfsdir, buf);
+ } else
+ ieee80211_debugfs_key_remove_mgmt_default(sdata);
+}
+
+void ieee80211_debugfs_key_remove_mgmt_default(struct ieee80211_sub_if_data *sdata)
+{
+ if (!sdata)
+ return;
+
+ debugfs_remove(sdata->common_debugfs.default_mgmt_key);
+ sdata->common_debugfs.default_mgmt_key = NULL;
+}
+
void ieee80211_debugfs_key_sta_del(struct ieee80211_key *key,
struct sta_info *sta)
{
diff --git a/net/mac80211/debugfs_key.h b/net/mac80211/debugfs_key.h
index b1a3754..54717b4 100644
--- a/net/mac80211/debugfs_key.h
+++ b/net/mac80211/debugfs_key.h
@@ -6,6 +6,10 @@
void ieee80211_debugfs_key_remove(struct ieee80211_key *key);
void ieee80211_debugfs_key_add_default(struct ieee80211_sub_if_data *sdata);
void ieee80211_debugfs_key_remove_default(struct ieee80211_sub_if_data *sdata);
+void ieee80211_debugfs_key_add_mgmt_default(
+ struct ieee80211_sub_if_data *sdata);
+void ieee80211_debugfs_key_remove_mgmt_default(
+ struct ieee80211_sub_if_data *sdata);
void ieee80211_debugfs_key_sta_del(struct ieee80211_key *key,
struct sta_info *sta);
#else
@@ -19,6 +23,12 @@
static inline void ieee80211_debugfs_key_remove_default(
struct ieee80211_sub_if_data *sdata)
{}
+static inline void ieee80211_debugfs_key_add_mgmt_default(
+ struct ieee80211_sub_if_data *sdata)
+{}
+static inline void ieee80211_debugfs_key_remove_mgmt_default(
+ struct ieee80211_sub_if_data *sdata)
+{}
static inline void ieee80211_debugfs_key_sta_del(struct ieee80211_key *key,
struct sta_info *sta)
{}
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 20af92a..8c32457 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -409,8 +409,10 @@
unsigned int fragment_next;
#define NUM_DEFAULT_KEYS 4
- struct ieee80211_key *keys[NUM_DEFAULT_KEYS];
+#define NUM_DEFAULT_MGMT_KEYS 2
+ struct ieee80211_key *keys[NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS];
struct ieee80211_key *default_key;
+ struct ieee80211_key *default_mgmt_key;
u16 sequence_number;
@@ -482,6 +484,7 @@
} debugfs;
struct {
struct dentry *default_key;
+ struct dentry *default_mgmt_key;
} common_debugfs;
#ifdef CONFIG_MAC80211_MESH
diff --git a/net/mac80211/key.c b/net/mac80211/key.c
index b0a025c..19b480d 100644
--- a/net/mac80211/key.c
+++ b/net/mac80211/key.c
@@ -18,6 +18,7 @@
#include "ieee80211_i.h"
#include "debugfs_key.h"
#include "aes_ccm.h"
+#include "aes_cmac.h"
/**
@@ -215,13 +216,38 @@
spin_unlock_irqrestore(&sdata->local->key_lock, flags);
}
+static void
+__ieee80211_set_default_mgmt_key(struct ieee80211_sub_if_data *sdata, int idx)
+{
+ struct ieee80211_key *key = NULL;
+
+ if (idx >= NUM_DEFAULT_KEYS &&
+ idx < NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS)
+ key = sdata->keys[idx];
+
+ rcu_assign_pointer(sdata->default_mgmt_key, key);
+
+ if (key)
+ add_todo(key, KEY_FLAG_TODO_DEFMGMTKEY);
+}
+
+void ieee80211_set_default_mgmt_key(struct ieee80211_sub_if_data *sdata,
+ int idx)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&sdata->local->key_lock, flags);
+ __ieee80211_set_default_mgmt_key(sdata, idx);
+ spin_unlock_irqrestore(&sdata->local->key_lock, flags);
+}
+
static void __ieee80211_key_replace(struct ieee80211_sub_if_data *sdata,
struct sta_info *sta,
struct ieee80211_key *old,
struct ieee80211_key *new)
{
- int idx, defkey;
+ int idx, defkey, defmgmtkey;
if (new)
list_add(&new->list, &sdata->key_list);
@@ -237,13 +263,19 @@
idx = new->conf.keyidx;
defkey = old && sdata->default_key == old;
+ defmgmtkey = old && sdata->default_mgmt_key == old;
if (defkey && !new)
__ieee80211_set_default_key(sdata, -1);
+ if (defmgmtkey && !new)
+ __ieee80211_set_default_mgmt_key(sdata, -1);
rcu_assign_pointer(sdata->keys[idx], new);
if (defkey && new)
__ieee80211_set_default_key(sdata, new->conf.keyidx);
+ if (defmgmtkey && new)
+ __ieee80211_set_default_mgmt_key(sdata,
+ new->conf.keyidx);
}
if (old) {
@@ -262,7 +294,7 @@
{
struct ieee80211_key *key;
- BUG_ON(idx < 0 || idx >= NUM_DEFAULT_KEYS);
+ BUG_ON(idx < 0 || idx >= NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS);
key = kzalloc(sizeof(struct ieee80211_key) + key_len, GFP_KERNEL);
if (!key)
@@ -291,6 +323,10 @@
key->conf.iv_len = CCMP_HDR_LEN;
key->conf.icv_len = CCMP_MIC_LEN;
break;
+ case ALG_AES_CMAC:
+ key->conf.iv_len = 0;
+ key->conf.icv_len = sizeof(struct ieee80211_mmie);
+ break;
}
memcpy(key->conf.key, key_data, key_len);
INIT_LIST_HEAD(&key->list);
@@ -308,6 +344,19 @@
}
}
+ if (alg == ALG_AES_CMAC) {
+ /*
+ * 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 (!key->u.aes_cmac.tfm) {
+ kfree(key);
+ return NULL;
+ }
+ }
+
return key;
}
@@ -461,6 +510,8 @@
if (key->conf.alg == ALG_CCMP)
ieee80211_aes_key_free(key->u.ccmp.tfm);
+ if (key->conf.alg == ALG_AES_CMAC)
+ ieee80211_aes_cmac_key_free(key->u.aes_cmac.tfm);
ieee80211_debugfs_key_remove(key);
kfree(key);
@@ -483,6 +534,7 @@
list_del_init(&key->todo);
todoflags = key->flags & (KEY_FLAG_TODO_ADD_DEBUGFS |
KEY_FLAG_TODO_DEFKEY |
+ KEY_FLAG_TODO_DEFMGMTKEY |
KEY_FLAG_TODO_HWACCEL_ADD |
KEY_FLAG_TODO_HWACCEL_REMOVE |
KEY_FLAG_TODO_DELETE);
@@ -500,6 +552,11 @@
ieee80211_debugfs_key_add_default(key->sdata);
work_done = true;
}
+ if (todoflags & KEY_FLAG_TODO_DEFMGMTKEY) {
+ ieee80211_debugfs_key_remove_mgmt_default(key->sdata);
+ ieee80211_debugfs_key_add_mgmt_default(key->sdata);
+ work_done = true;
+ }
if (todoflags & KEY_FLAG_TODO_HWACCEL_ADD) {
ieee80211_key_enable_hw_accel(key);
work_done = true;
@@ -535,6 +592,7 @@
ieee80211_key_lock();
ieee80211_debugfs_key_remove_default(sdata);
+ ieee80211_debugfs_key_remove_mgmt_default(sdata);
spin_lock_irqsave(&sdata->local->key_lock, flags);
list_for_each_entry_safe(key, tmp, &sdata->key_list, list)
diff --git a/net/mac80211/key.h b/net/mac80211/key.h
index 73ac28c..215d3ef 100644
--- a/net/mac80211/key.h
+++ b/net/mac80211/key.h
@@ -46,6 +46,8 @@
* acceleration.
* @KEY_FLAG_TODO_DEFKEY: Key is default key and debugfs needs to be updated.
* @KEY_FLAG_TODO_ADD_DEBUGFS: Key needs to be added to debugfs.
+ * @KEY_FLAG_TODO_DEFMGMTKEY: Key is default management key and debugfs needs
+ * to be updated.
*/
enum ieee80211_internal_key_flags {
KEY_FLAG_UPLOADED_TO_HARDWARE = BIT(0),
@@ -54,6 +56,7 @@
KEY_FLAG_TODO_HWACCEL_REMOVE = BIT(3),
KEY_FLAG_TODO_DEFKEY = BIT(4),
KEY_FLAG_TODO_ADD_DEBUGFS = BIT(5),
+ KEY_FLAG_TODO_DEFMGMTKEY = BIT(6),
};
struct tkip_ctx {
@@ -124,6 +127,7 @@
struct dentry *tx_spec;
struct dentry *rx_spec;
struct dentry *replays;
+ struct dentry *icverrors;
struct dentry *key;
struct dentry *ifindex;
int cnt;
@@ -150,6 +154,8 @@
struct sta_info *sta);
void ieee80211_key_free(struct ieee80211_key *key);
void ieee80211_set_default_key(struct ieee80211_sub_if_data *sdata, int idx);
+void ieee80211_set_default_mgmt_key(struct ieee80211_sub_if_data *sdata,
+ int idx);
void ieee80211_free_keys(struct ieee80211_sub_if_data *sdata);
void ieee80211_enable_keys(struct ieee80211_sub_if_data *sdata);
void ieee80211_disable_keys(struct ieee80211_sub_if_data *sdata);
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index b68e082..abc3aa5 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -446,6 +446,52 @@
return RX_CONTINUE;
}
+
+static int ieee80211_is_unicast_robust_mgmt_frame(struct sk_buff *skb)
+{
+ struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
+
+ if (skb->len < 24 || is_multicast_ether_addr(hdr->addr1))
+ return 0;
+
+ return ieee80211_is_robust_mgmt_frame(hdr);
+}
+
+
+static int ieee80211_is_multicast_robust_mgmt_frame(struct sk_buff *skb)
+{
+ struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
+
+ if (skb->len < 24 || !is_multicast_ether_addr(hdr->addr1))
+ return 0;
+
+ return ieee80211_is_robust_mgmt_frame(hdr);
+}
+
+
+/* Get the BIP key index from MMIE; return -1 if this is not a BIP frame */
+static int ieee80211_get_mmie_keyidx(struct sk_buff *skb)
+{
+ struct ieee80211_mgmt *hdr = (struct ieee80211_mgmt *) skb->data;
+ struct ieee80211_mmie *mmie;
+
+ if (skb->len < 24 + sizeof(*mmie) ||
+ !is_multicast_ether_addr(hdr->da))
+ return -1;
+
+ if (!ieee80211_is_robust_mgmt_frame((struct ieee80211_hdr *) hdr))
+ return -1; /* not a robust management frame */
+
+ mmie = (struct ieee80211_mmie *)
+ (skb->data + skb->len - sizeof(*mmie));
+ if (mmie->element_id != WLAN_EID_MMIE ||
+ mmie->length != sizeof(*mmie) - 2)
+ return -1;
+
+ return le16_to_cpu(mmie->key_id);
+}
+
+
static ieee80211_rx_result
ieee80211_rx_mesh_check(struct ieee80211_rx_data *rx)
{
@@ -561,21 +607,23 @@
int hdrlen;
ieee80211_rx_result result = RX_DROP_UNUSABLE;
struct ieee80211_key *stakey = NULL;
+ int mmie_keyidx = -1;
/*
* Key selection 101
*
- * There are three types of keys:
+ * There are four types of keys:
* - GTK (group keys)
+ * - IGTK (group keys for management frames)
* - PTK (pairwise keys)
* - STK (station-to-station pairwise keys)
*
* When selecting a key, we have to distinguish between multicast
* (including broadcast) and unicast frames, the latter can only
- * use PTKs and STKs while the former always use GTKs. Unless, of
- * course, actual WEP keys ("pre-RSNA") are used, then unicast
- * frames can also use key indizes like GTKs. Hence, if we don't
- * have a PTK/STK we check the key index for a WEP key.
+ * use PTKs and STKs while the former always use GTKs and IGTKs.
+ * Unless, of course, actual WEP keys ("pre-RSNA") are used, then
+ * unicast frames can also use key indices like GTKs. Hence, if we
+ * don't have a PTK/STK we check the key index for a WEP key.
*
* Note that in a regular BSS, multicast frames are sent by the
* AP only, associated stations unicast the frame to the AP first
@@ -588,8 +636,14 @@
* possible.
*/
- if (!ieee80211_has_protected(hdr->frame_control))
- return RX_CONTINUE;
+ if (!ieee80211_has_protected(hdr->frame_control)) {
+ if (!ieee80211_is_mgmt(hdr->frame_control) ||
+ rx->sta == NULL || !test_sta_flags(rx->sta, WLAN_STA_MFP))
+ return RX_CONTINUE;
+ mmie_keyidx = ieee80211_get_mmie_keyidx(rx->skb);
+ if (mmie_keyidx < 0)
+ return RX_CONTINUE;
+ }
/*
* No point in finding a key and decrypting if the frame is neither
@@ -603,6 +657,16 @@
if (!is_multicast_ether_addr(hdr->addr1) && stakey) {
rx->key = stakey;
+ } else if (mmie_keyidx >= 0) {
+ /* Broadcast/multicast robust management frame / BIP */
+ if ((rx->status->flag & RX_FLAG_DECRYPTED) &&
+ (rx->status->flag & RX_FLAG_IV_STRIPPED))
+ return RX_CONTINUE;
+
+ if (mmie_keyidx < NUM_DEFAULT_KEYS ||
+ mmie_keyidx >= NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS)
+ return RX_DROP_MONITOR; /* unexpected BIP keyidx */
+ rx->key = rcu_dereference(rx->sdata->keys[mmie_keyidx]);
} else {
/*
* The device doesn't give us the IV so we won't be
@@ -665,6 +729,9 @@
case ALG_CCMP:
result = ieee80211_crypto_ccmp_decrypt(rx);
break;
+ case ALG_AES_CMAC:
+ result = ieee80211_crypto_aes_cmac_decrypt(rx);
+ break;
}
/* either the frame has been decrypted or will be dropped */
@@ -1112,6 +1179,15 @@
/* Drop unencrypted frames if key is set. */
if (unlikely(!ieee80211_has_protected(fc) &&
!ieee80211_is_nullfunc(fc) &&
+ (!ieee80211_is_mgmt(fc) ||
+ (ieee80211_is_unicast_robust_mgmt_frame(rx->skb) &&
+ rx->sta && test_sta_flags(rx->sta, WLAN_STA_MFP))) &&
+ (rx->key || rx->sdata->drop_unencrypted)))
+ return -EACCES;
+ /* BIP does not use Protected field, so need to check MMIE */
+ if (unlikely(rx->sta && test_sta_flags(rx->sta, WLAN_STA_MFP) &&
+ ieee80211_is_multicast_robust_mgmt_frame(rx->skb) &&
+ ieee80211_get_mmie_keyidx(rx->skb) < 0 &&
(rx->key || rx->sdata->drop_unencrypted)))
return -EACCES;
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 50c6c4f..ad53ea9 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -425,6 +425,9 @@
tx->key = NULL;
else if (tx->sta && (key = rcu_dereference(tx->sta->key)))
tx->key = key;
+ else if (ieee80211_is_mgmt(hdr->frame_control) &&
+ (key = rcu_dereference(tx->sdata->default_mgmt_key)))
+ tx->key = key;
else if ((key = rcu_dereference(tx->sdata->default_key)))
tx->key = key;
else if (tx->sdata->drop_unencrypted &&
@@ -453,6 +456,10 @@
tx->skb))
tx->key = NULL;
break;
+ case ALG_AES_CMAC:
+ if (!ieee80211_is_mgmt(hdr->frame_control))
+ tx->key = NULL;
+ break;
}
}
@@ -808,6 +815,8 @@
return ieee80211_crypto_tkip_encrypt(tx);
case ALG_CCMP:
return ieee80211_crypto_ccmp_encrypt(tx);
+ case ALG_AES_CMAC:
+ return ieee80211_crypto_aes_cmac_encrypt(tx);
}
/* not reached */