From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        syzbot+614e82b88a1a4973e534@syzkaller.appspotmail.com,
        Johannes Berg <johannes.berg@intel.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.4 14/71] mac80211: track only QoS data frames for admission control
Date:   Mon, 20 Dec 2021 15:34:03 +0100
Message-Id: <20211220143026.170509004@linuxfoundation.org>
In-Reply-To: <20211220143025.683747691@linuxfoundation.org>
References: <20211220143025.683747691@linuxfoundation.org>
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From: Johannes Berg <johannes.berg@intel.com>

[ Upstream commit d5e568c3a4ec2ddd23e7dc5ad5b0c64e4f22981a ]

For admission control, obviously all of that only works for
QoS data frames, otherwise we cannot even access the QoS
field in the header.

Syzbot reported (see below) an uninitialized value here due
to a status of a non-QoS nullfunc packet, which isn't even
long enough to contain the QoS header.

Fix this to only do anything for QoS data packets.

Reported-by: syzbot+614e82b88a1a4973e534@syzkaller.appspotmail.com
Fixes: 02219b3abca5 ("mac80211: add WMM admission control support")
Link: https://lore.kernel.org/r/20211122124737.dad29e65902a.Ieb04587afacb27c14e0de93ec1bfbefb238cc2a0@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/mac80211/mlme.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index ccaf2389ccc1d..5c727af01143f 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -2418,11 +2418,18 @@ static void ieee80211_sta_tx_wmm_ac_notify(struct ieee80211_sub_if_data *sdata,
 					   u16 tx_time)
 {
 	struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
-	u16 tid = ieee80211_get_tid(hdr);
-	int ac = ieee80211_ac_from_tid(tid);
-	struct ieee80211_sta_tx_tspec *tx_tspec = &ifmgd->tx_tspec[ac];
+	u16 tid;
+	int ac;
+	struct ieee80211_sta_tx_tspec *tx_tspec;
 	unsigned long now = jiffies;
 
+	if (!ieee80211_is_data_qos(hdr->frame_control))
+		return;
+
+	tid = ieee80211_get_tid(hdr);
+	ac = ieee80211_ac_from_tid(tid);
+	tx_tspec = &ifmgd->tx_tspec[ac];
+
 	if (likely(!tx_tspec->admitted_time))
 		return;
 
-- 
2.33.0