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[34.83.123.78]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2ddc17ba65csm13032565ad.52.2026.09.19.15.34.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 19 Sep 2026 15:34:33 -0700 (PDT) From: Hui Peng 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 Message-ID: <20260919223433.3882618-1-benquike@gmail.com> X-Mailer: git-send-email 2.55.0.1082.g2b9226bbc0-goog Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 --- 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) {