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Commit 46f6b060 authored by Masashi Honma's avatar Masashi Honma Committed by Johannes Berg
Browse files

mac80211: Encrypt "Group addressed privacy" action frames 



Previously, the action frames to group address was not encrypted. But
[1] "Table 8-38 Category values" indicates "Mesh" and "Multihop" category
action frames should be encrypted (Group addressed privacy == yes). And the
encyption key should be MGTK ([1] 10.13 Group addressed robust management frame
procedures). So this patch modifies the code to make it suitable for spec.

[1] IEEE Std 802.11-2012

Signed-off-by: default avatarMasashi Honma <masashi.honma@gmail.com>
Signed-off-by: default avatarJohannes Berg <johannes@sipsolutions.net>
parent 49708e37

include/linux/ieee80211.h

+30 −0
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 


#include <linux/types.h>

#include <linux/if_ether.h>

#include <linux/etherdevice.h>

#include <asm/byteorder.h>

#include <asm/unaligned.h>
@@ -2486,6 +2487,35 @@ static inline bool ieee80211_is_public_action(struct ieee80211_hdr *hdr, 
	return mgmt->u.action.category == WLAN_CATEGORY_PUBLIC;

}



/**

 * _ieee80211_is_group_privacy_action - check if frame is a group addressed

 * privacy action frame

 * @hdr: the frame

 */

static inline bool _ieee80211_is_group_privacy_action(struct ieee80211_hdr *hdr)

{

	struct ieee80211_mgmt *mgmt = (void *)hdr;



	if (!ieee80211_is_action(hdr->frame_control) ||

	    !is_multicast_ether_addr(hdr->addr1))

		return false;



	return mgmt->u.action.category == WLAN_CATEGORY_MESH_ACTION ||

	       mgmt->u.action.category == WLAN_CATEGORY_MULTIHOP_ACTION;

}



/**

 * ieee80211_is_group_privacy_action - check if frame is a group addressed

 * privacy action frame

 * @skb: the skb containing the frame, length will be checked

 */

static inline bool ieee80211_is_group_privacy_action(struct sk_buff *skb)

{

	if (skb->len < IEEE80211_MIN_ACTION_SIZE)

		return false;

	return _ieee80211_is_group_privacy_action((void *)skb->data);

}



/**

 * ieee80211_tu_to_usec - convert time units (TU) to microseconds

 * @tu: the TUs

net/mac80211/rx.c

+6 −1
Original line number Diff line number Diff line
@@ -1624,8 +1624,13 @@ ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx) 
		if (mmie_keyidx < NUM_DEFAULT_KEYS ||

		    mmie_keyidx >= NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS)

			return RX_DROP_MONITOR; /* unexpected BIP keyidx */

		if (rx->sta)

		if (rx->sta) {

			if (ieee80211_is_group_privacy_action(skb) &&

			    test_sta_flag(rx->sta, WLAN_STA_MFP))

				return RX_DROP_MONITOR;



			rx->key = rcu_dereference(rx->sta->gtk[mmie_keyidx]);

		}

		if (!rx->key)

			rx->key = rcu_dereference(rx->sdata->keys[mmie_keyidx]);

	} else if (!ieee80211_has_protected(fc)) {

net/mac80211/tx.c

+5 −1
Original line number Diff line number Diff line
@@ -593,6 +593,9 @@ ieee80211_tx_h_select_key(struct ieee80211_tx_data *tx) 
	else if (tx->sta &&

		 (key = rcu_dereference(tx->sta->ptk[tx->sta->ptk_idx])))

		tx->key = key;

	else if (ieee80211_is_group_privacy_action(tx->skb) &&

		(key = rcu_dereference(tx->sdata->default_multicast_key)))

		tx->key = key;

	else if (ieee80211_is_mgmt(hdr->frame_control) &&

		 is_multicast_ether_addr(hdr->addr1) &&

		 ieee80211_is_robust_mgmt_frame(tx->skb) &&
@@ -625,7 +628,8 @@ ieee80211_tx_h_select_key(struct ieee80211_tx_data *tx) 
		case WLAN_CIPHER_SUITE_GCMP_256:

			if (!ieee80211_is_data_present(hdr->frame_control) &&

			    !ieee80211_use_mfp(hdr->frame_control, tx->sta,

					       tx->skb))

					       tx->skb) &&

			    !ieee80211_is_group_privacy_action(tx->skb))

				tx->key = NULL;

			else

				skip_hw = (tx->key->conf.flags &