Registering a process as a machine means a caller can get machined
to send sigterm to it, and more. If an unpriv user is registering,
ensure the registered process is actually owned by the user.
Follow-up for adaff8eb35
Registering a process as a machine means a caller can get machined
to send sigterm to it, and more. If an unpriv user is registering,
ensure the registered process is actually owned by the user.
Follow-up for adaff8eb35