Re: [PATCH] net: usb: sr9700: validate receive packet extent

sr9700_rx_fixup() copies len bytes from skb->data + SR_RX_OVERHEAD when
a URB contains multiple packets. The old check compared len against
skb->len, but the source pointer has already skipped SR_RX_OVERHEAD
bytes.

Validate len against the remaining bytes after SR_RX_OVERHEAD before the
copy and cursor advance.

Signed-off-by: Pengpeng Hou <redacted>
---

diff --git a/drivers/net/usb/sr9700.c b/drivers/net/usb/sr9700.c
--- a/drivers/net/usb/sr9700.c
+++ b/drivers/net/usb/sr9700.c

@@ -355,7 +355,8 @@
                /* 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 */