Traditional UNIX access control

• Filesystem access control (RWX)
• Process ownership
• UID 0

SETUID and SETGID

• setuid(2)/getuid(2) (and the others)
• setgid(2)/getgid(2) (and the others)

Finer grained

• SELINUX
• capabilities(7)
• PAM
• Extended attributes

Real world access control

• Using a root password
• Using a ssh key
• su / sudo