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From:   Felix Fietkau <nbd@nbd.name>
To:     linux-wireless@vger.kernel.org
Subject: [PATCH 4/4] mt76: clear skb pointers from rx aggregation reorder buffer during cleanup
Date:   Sun, 22 Dec 2019 16:07:17 +0100
Message-Id: <20191222150717.51379-4-nbd@nbd.name>
In-Reply-To: <20191222150717.51379-1-nbd@nbd.name>
References: <20191222150717.51379-1-nbd@nbd.name>
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During the cleanup of the aggregation session, a rx handler (or release timer)
on another CPU might still hold a pointer to the reorder buffer and could
attempt to release some packets.
Clearing pointers during cleanup avoids a theoretical use-after-free bug here.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
 drivers/net/wireless/mediatek/mt76/agg-rx.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/wireless/mediatek/mt76/agg-rx.c b/drivers/net/wireless/mediatek/mt76/agg-rx.c
index 6d64c2c4a159..3815d28a32ea 100644
--- a/drivers/net/wireless/mediatek/mt76/agg-rx.c
+++ b/drivers/net/wireless/mediatek/mt76/agg-rx.c
@@ -276,6 +276,7 @@ static void mt76_rx_aggr_shutdown(struct mt76_dev *dev, struct mt76_rx_tid *tid)
 		if (!skb)
 			continue;
 
+		tid->reorder_buf[i] = NULL;
 		tid->nframes--;
 		dev_kfree_skb(skb);
 	}
-- 
2.24.0