From c06bde80ae7a7b595732f7cabcb92cf08db9d56a Mon Sep 17 00:00:00 2001 From: Pengpeng Hou Date: Sun, 20 Sep 2026 11:47:45 +0800 Subject: [PATCH] net: usb: sr9700: include receive overhead in the length check The receive fixup subtracts the Ethernet CRC from the reported packet length, but compares that payload length against the whole remaining receive buffer. The following copy starts after the three-byte header, and the cursor advance consumes both that header and the four-byte CRC. Require the payload to fit after SR_RX_OVERHEAD before copying it or advancing to the next packet. The loop already ensures that the remaining buffer is larger than the overhead, so the subtraction is safe. The issue was found by our static-analysis tool. Fixes: c9b37458e956 ("USB2NET : SR9700 : One chip USB 1.1 USB2NET SR9700Device Driver Support") Reviewed-by: Ethan Nelson-Moore Tested-by: Ethan Nelson-Moore Signed-off-by: Pengpeng Hou Link: https://patch.msgid.link/20260920034745.18468-1-hppiscas@163.com Signed-off-by: Jakub Kicinski --- drivers/net/usb/sr9700.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/net/usb/sr9700.c b/drivers/net/usb/sr9700.c index 937e6fef3ac6..50981a28376a 100644 --- a/drivers/net/usb/sr9700.c +++ b/drivers/net/usb/sr9700.c @@ -355,7 +355,8 @@ static int sr9700_rx_fixup(struct usbnet *dev, struct sk_buff *skb) /* ignore the CRC length */ len = (skb->data[1] | (skb->data[2] << 8)) - 4; - if (len > ETH_FRAME_LEN || len > skb->len || len < 0) + if (len > ETH_FRAME_LEN || len < 0 || + len > skb->len - SR_RX_OVERHEAD) return 0; /* the last packet of current skb */