On Fri, Feb 15, 2019 at 04:08:46PM +0000, David Howells wrote: > Currently sys_move_mount() and sys_mount(MS_MOVE) prevent the caller from > moving a mount into a namespace not their own. Relax this such that any > mount can be mounted onto any given mountpoint provided that the source > mount is either detached or the same namespace as the destination. > > This permits container namespaces to be built from the outside rather than > from the inside. I'm looking forward to your analysis of security implications, as well as the proof that attach_recursive_mnt() won't get confused by that...