> > The following extra security measures are taken for unprivileged > > mounts: > > > > - usermounts are limited by a sysctl tunable > > - force "nosuid,nodev" mount options on the created mount > > The original userspace "user=" solution also implies the "noexec" > option by default (you can override the default by "exec" option). Unlike "nosuid" and "nodev", I don't think "noexec" has real security benefits. > It means the kernel based solution is not fully compatible ;-( Oh, I don't think that matters. For traditional /etc/fstab based user mounts, mount(8) will have to remain suid-root, the kernel can't replace the fstab check. In fact the latest patches don't even support these "legacy" user mounts too well: setting the owner of a mount gives not only umount privilege, but the ability to submount. This is not necessarily a good thing for these kinds of user mounts. We could add a new "nosubmount" or similar flag, to prevent submounting, but that again would go against the simplicity of the current approach, so I'm not sure it's worth it. Miklos - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
