[AshamedCaptain]

Yes, they are. The kernel for obvious reasons. Second, the IPC server now has to handle (and possibly pass through data) from the untrusted environment, unless you are happy with a sudo that does not even ferry stdio. Frankly, having properly working suid (the kernel does most of the job) sounds MUCH easier than having this type of APIs exposed to arbitrary users from pid1. In fact, as per Lennart's last sudo tty bug, the issue was with how sudo was exec()ing the target binary in the _target_ context (not the original context). Having sudo as a global daemon instead of a suid exec is not going to protect you against those; actually may make them worse for all I know.