Have you used advanced access control mechanisms in Linux to configure user and group permissions?

In Linux, advanced access control mechanisms include the use of ACLs (Access Control Lists) and SELinux/AppArmor for more fine-grained configuration of user and group permissions.

ACLs allow setting permissions not only for the owner, group, and others but also for specific users and groups. The commands setfacl and getfacl are used to work with ACLs.

Example of setting file permissions for a specific user:

setfacl -m u:username:rwx filename
getfacl filename

SELinux and AppArmor provide mandatory access control, allowing to restrict the actions of processes and users at the security policy level, which is useful for enhancing system security.

Thus, advanced mechanisms enable flexible configuration of access rights, going beyond the standard rwx for owner, group, and others.