"The Simplified Mandatory Access Control Kernel is a security
module designed to harden Linux systems through the addition of
mandatory access control policies; it was covered here last August.
Like SELinux, SMACK works by attaching labels to processes, files,
and other system objects and implementing rules describing what
kinds of access are allowed by specific combinations of labels.
Unlike SELinux, though, SMACK was designed specifically for
simplicity of administration..."