Some university lecture notes claim that
In Unix systems, it is written into the operating system that some functionalities can only be accessed by the
rootuser: modifying passwords, accessing to network ports used for communication protocols, interaction with hardware, etc.
Is this description correct? Where exactly is this implemented "in the OS"? How can non-root users change their own passwords if they cannot write
As far as I know, there are UNIX-based systems like SELinux, where the root user doesn't have unlimited powers?