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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Emmanuel Grumbach <emmanuel.grumbach@intel.com>,
        Johannes Berg <johannes.berg@intel.com>
Subject: [PATCH 4.4 91/91] mac80211: ignore NullFunc frames in the duplicate detection
Date:   Tue, 11 Dec 2018 16:41:50 +0100
Message-Id: <20181211151614.389716789@linuxfoundation.org>
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4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

commit 990d71846a0b7281bd933c34d734e6afc7408e7e upstream.

NullFunc packets should never be duplicate just like
QoS-NullFunc packets.

We saw a client that enters / exits power save with
NullFunc frames (and not with QoS-NullFunc) despite the
fact that the association supports HT.
This specific client also re-uses a non-zero sequence number
for different NullFunc frames.
At some point, the client had to send a retransmission of
the NullFunc frame and we dropped it, leading to a
misalignment in the power save state.
Fix this by never consider a NullFunc frame as duplicate,
just like we do for QoS NullFunc frames.

This fixes https://bugzilla.kernel.org/show_bug.cgi?id=201449

CC: <stable@vger.kernel.org>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 net/mac80211/rx.c |    1 +
 1 file changed, 1 insertion(+)

--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -1109,6 +1109,7 @@ ieee80211_rx_h_check_dup(struct ieee8021
 		return RX_CONTINUE;
 
 	if (ieee80211_is_ctl(hdr->frame_control) ||
+	    ieee80211_is_nullfunc(hdr->frame_control) ||
 	    ieee80211_is_qos_nullfunc(hdr->frame_control) ||
 	    is_multicast_ether_addr(hdr->addr1))
 		return RX_CONTINUE;