mac80211: Fix robust management frame handling (MFP)

commit d211e90e upstream.

Commit e34e09401ee9888dd662b2fca5d607794a56daf2 incorrectly removed
use of ieee80211_has_protected() from the management frame case and in
practice, made this validation drop all Action frames when MFP is
enabled. This should have only been done for frames with Protected
field set to zero.
Signed-off-by: Jouni Malinen <j@w1.fi>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

net/mac80211/rx.c

@@ -1414,7 +1414,8 @@ ieee80211_drop_unencrypted_mgmt(struct ieee80211_rx_data *rx)
 		return res;
 
 	if (rx->sta && test_sta_flags(rx->sta, WLAN_STA_MFP)) {
-		if (unlikely(ieee80211_is_unicast_robust_mgmt_frame(rx->skb) &&
+		if (unlikely(!ieee80211_has_protected(fc) &&
+			     ieee80211_is_unicast_robust_mgmt_frame(rx->skb) &&
 			     rx->key))
 			return -EACCES;
 		/* BIP does not use Protected field, so need to check MMIE */