But with one key difference: it’s *not* in fact SUID. Instead it just asks the service manager to invoke a command or shell under the target user’s UID. It allocates a new PTY for that, and then shovels data back and forth from the originating TTY and this PTY. Or in other words: the target command is invoked in an isolated exec context, freshly forked off PID 1, without inheriting any context from the client (well, admittedly, we *do* propagate $TERM, but that’s an explicit exception, i.e. allowlist rather than denylist).
Sudo also blocks almost all environment variables, with the option to set or copy them on demand. I assume that run0 will have similar facilities to propagate variables on demand.
PS: This is my technical understanding. Personally, I don’t like systemd eating up all the other utilities.
Unfortunately, this is about as easy as it gets. Practically though, it isn’t going to matter. It sounds like run0 will be a drop-in replacement for sudo. We will know for sure in about 3 days (at the rate at which they assimilate features).
