Too many tweaks to be worth it. To this date we still find bugs in sudo, interactive shells, weird env var interactions from su and inheriting variables. The U

Too many tweaks to be worth it. To this date we still find bugs in sudo, interactive shells, weird env var interactions from su and inheriting variables. The Unix permissions system is complicated yet insufficient for protecting systems. There are multiple, orthogonal machineries for isolation (jails, chroot, namespaces,SELinux thingies, setuid and sticky bits) and they all interact in horrendous ways that leave huge security gaps. Just reconsidering their use cases and redoing al lot of that having learned the lessons of the past twenty years is a huge advance.