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Commit 11cad2a4 authored by Johannes Berg's avatar Johannes Berg Committed by Sasha Levin
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mac80211: drop data frames without key on encrypted links 



commit a0761a301746ec2d92d7fcb82af69c0a6a4339aa upstream.

If we know that we have an encrypted link (based on having had
a key configured for TX in the past) then drop all data frames
in the key selection handler if there's no key anymore.

This fixes an issue with mac80211 internal TXQs - there we can
buffer frames for an encrypted link, but then if the key is no
longer there when they're dequeued, the frames are sent without
encryption. This happens if a station is disconnected while the
frames are still on the TXQ.

Detecting that a link should be encrypted based on a first key
having been configured for TX is fine as there are no use cases
for a connection going from with encryption to no encryption.
With extended key IDs, however, there is a case of having a key
configured for only decryption, so we can't just trigger this
behaviour on a key being configured.

Cc: stable@vger.kernel.org
Reported-by: default avatarJouni Malinen <j@w1.fi>
Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
Signed-off-by: default avatarLuca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20200326150855.6865c7f28a14.I9fb1d911b064262d33e33dfba730cdeef83926ca@changeid


Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
[pali: Backported to 4.19 and older versions]
Signed-off-by: default avatarPali Rohár <pali@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 6a9449e9

net/mac80211/debugfs_sta.c

+1 −0
Original line number Diff line number Diff line
@@ -80,6 +80,7 @@ static const char * const sta_flag_names[] = { 
	FLAG(MPSP_OWNER),

	FLAG(MPSP_RECIPIENT),

	FLAG(PS_DELIVER),

	FLAG(USES_ENCRYPTION),

#undef FLAG

};

net/mac80211/key.c

+1 −0
Original line number Diff line number Diff line
@@ -341,6 +341,7 @@ static void ieee80211_key_replace(struct ieee80211_sub_if_data *sdata, 
	if (sta) {

		if (pairwise) {

			rcu_assign_pointer(sta->ptk[idx], new);

			set_sta_flag(sta, WLAN_STA_USES_ENCRYPTION);

			sta->ptk_idx = idx;

			ieee80211_check_fast_xmit(sta);

		} else {

net/mac80211/sta_info.h

+1 −0
Original line number Diff line number Diff line
@@ -102,6 +102,7 @@ enum ieee80211_sta_info_flags { 
	WLAN_STA_MPSP_OWNER,

	WLAN_STA_MPSP_RECIPIENT,

	WLAN_STA_PS_DELIVER,

	WLAN_STA_USES_ENCRYPTION,



	NUM_WLAN_STA_FLAGS,

};

net/mac80211/tx.c

+9 −3
Original line number Diff line number Diff line
@@ -593,9 +593,12 @@ ieee80211_tx_h_select_key(struct ieee80211_tx_data *tx) 
	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx->skb);

	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)tx->skb->data;



	if (unlikely(info->flags & IEEE80211_TX_INTFL_DONT_ENCRYPT))

	if (unlikely(info->flags & IEEE80211_TX_INTFL_DONT_ENCRYPT)) {

		tx->key = NULL;

	else if (tx->sta &&

		return TX_CONTINUE;

	}



	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) &&
@@ -657,6 +660,9 @@ ieee80211_tx_h_select_key(struct ieee80211_tx_data *tx) 
		if (!skip_hw && tx->key &&

		    tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE)

			info->control.hw_key = &tx->key->conf;

	} else if (!ieee80211_is_mgmt(hdr->frame_control) && tx->sta &&

		   test_sta_flag(tx->sta, WLAN_STA_USES_ENCRYPTION)) {

		return TX_DROP;

	}



	return TX_CONTINUE;