Preface
The secure state of an operating system or service is the result of a layered security approach. Systems can be shielded from the outside world through firewalls, operating systems have to be kept up to date with the latest security patches, services have to be configured properly, separation of duties has to be implemented for end users, and so forth.
Access controls are another layer that administrators have to look into. With Security Enhanced Linux (SELinux), the Linux ecosystem has a robust and established mandatory access control (MAC) system in place. Some distributions enable SELinux by default, others allow administrators to enable SELinux easily. Android, one of the most popular mobile device operating systems, has also embraced SELinux technology under the SEAndroid name.
But unlike Android, where users and applications are tightly controlled and where deviation from the setup and organization of files and resources is not allowed, desktops, workstations, and servers that implement Linux have greater diversity. As a result, configuring and tuning SELinux on these systems requires more knowledge of what SELinux is, how it works, and how it can be configured.
In this book, we discuss what SELinux is and how it is embedded in the Linux operating system. We go through various configuration aspects of SELinux and deal with several use cases that leverage SELinux’s strengths to further harden the system and services hosted on it.
