can: gs_usb: gs_usb_receive_bulk_callback(): check actual_length before accessing header

In the Linux kernel, the following vulnerability has been resolved: can: gs_usb: gs_usb_receive_bulk_callback(): check actual_length before accessing header The driver expects to receive a struct gs_host_frame in gs_usb_receive_bulk_callback(). Use struct_group to describe the header of the struct gs_host_frame and check that we have at least received the header before accessing any members of it. To resubmit the URB, do not dereference the pointer chain "dev->parent->hf_size_rx" but use "parent->hf_size_rx" instead. Since "urb->context" contains "parent", it is always defined, while "dev" is not defined if the URB it too short.