Kernel-memory disclosure via uninitialized netlink padding

Information disclosure in Linux kernel drop_monitor allows local users to read uninitialized kernel memory through netlink messages. net_dm_packet_report_fill() and net_dm_hw_packet_report_fill() reserve aligned NET_DM_ATTR_PAYLOAD space but copy only the payload, leaving one to three padding bytes uninitialized when its length is not divisible by four. A low-privileged local user can receive those bytes; the observed consequence is a small kernel-memory disclosure through the software path.