stub_send_ret_submit() handles urb with a potential null transfer_buffer,
when it replays a packet with potential malicious data that could contain
a null buffer. Add a check for the condition when actual_length > 0 and
transfer_buffer is null.
Reported-by: NSecunia Research <vuln@secunia.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NShuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>