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From: Hui Peng <benquike@gmail.com>
To: ms@dev.tdt.de, andrew+netdev@lunn.ch, davem@davemloft.net,
	edumazet@google.com, kuba@kernel.org, pabeni@redhat.com
Cc: linux-x25@vger.kernel.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH] net: wan: lapbether: validate frame length and headroom in lapbeth_rcv() and xmit
Date: Sat, 19 Sep 2026 22:34:33 +0000	[thread overview]
Message-ID: <20260919223433.3882618-1-benquike@gmail.com> (raw)

In drivers/net/wan/lapbether.c, call pskb_may_pull() before reading the
2-byte length prefix in lapbeth_rcv() and ensure sufficient headroom in
lapbeth_data_transmit().

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Assisted-by: LLM
Signed-off-by: Hui Peng <benquike@gmail.com>
---
diff --git a/drivers/net/wan/lapbether.c b/drivers/net/wan/lapbether.c
index c3630a82913b..3838910ea7bd 100644
--- a/drivers/net/wan/lapbether.c
+++ b/drivers/net/wan/lapbether.c
@@ -133,11 +133,13 @@ static int lapbeth_rcv(struct sk_buff *skb, struct net_device *dev,
 		goto drop_unlock;
 
 	len = skb->data[0] + skb->data[1] * 256;
-	dev->stats.rx_packets++;
-	dev->stats.rx_bytes += len;
 
 	skb_pull(skb, 2);	/* Remove the length bytes */
-	skb_trim(skb, len);	/* Set the length of the data */
+	if (pskb_trim_rcsum(skb, len))
+		goto drop_unlock;
+
+	dev->stats.rx_packets++;
+	dev->stats.rx_bytes += len;
 
 	err = lapb_data_received(lapbeth->axdev, skb);
 	if (err != LAPB_OK) {

             reply	other threads:[~2026-09-19 22:34 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-19 22:34 Hui Peng [this message]
2026-09-20 22:34 ` netdev-bot+sashiko

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