can: kvaser_usb_leaf: kvaser_usb_leaf_wait_cmd(): validate received command extents

In the Linux kernel, the following vulnerability has been resolved: can: kvaser_usb_leaf: kvaser_usb_leaf_wait_cmd(): validate received command extents The wait and bulk receive paths walk variable-length commands from a USB buffer. A nonzero command shorter than CMD_HEADER_LEN can still be dispatched, and the wait path copies a matching command into a fixed caller-owned struct kvaser_cmd using the device-provided length. Reject nonzero commands that do not contain the fixed header or that extend beyond the current USB buffer item. In the wait path, also reject a matching command that exceeds the destination before copying it.