[PATCH 4.19 117/118] mac80211: ignore NullFunc frames in the duplicate detection

From: Greg Kroah-Hartman
Date: Tue Dec 11 2018 - 10:59:09 EST

4.19-stable review patch. If anyone has any objections, please let me know.


From: Emmanuel Grumbach <emmanuel.grumbach@xxxxxxxxx>

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@xxxxxxxxxxxxxxx>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@xxxxxxxxx>
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

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

--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -1372,6 +1372,7 @@ ieee80211_rx_h_check_dup(struct ieee8021

if (ieee80211_is_ctl(hdr->frame_control) ||
+ ieee80211_is_nullfunc(hdr->frame_control) ||
ieee80211_is_qos_nullfunc(hdr->frame_control) ||