Book Image

SELinux System Administration

By : Sven Vermeulen
Book Image

SELinux System Administration

By: Sven Vermeulen

Overview of this book

NSA Security-Enhanced Linux (SELinux) is a set of patches and added utilities to the Linux kernel to incorporate a strong, flexible, mandatory access control architecture into the major subsystems of the kernel. With its fine-grained yet flexible approach, it is no wonder Linux distributions are firing up SELinux as a default security measure. SELinux System Administration covers the majority of SELinux features through a mix of real-life scenarios, descriptions, and examples. Everything an administrator needs to further tune SELinux to suit their needs are present in this book. This book touches on various SELinux topics, guiding you through the configuration of SELinux contexts, definitions, and the assignment of SELinux roles, and finishes up with policy enhancements. All of SELinux's configuration handles, be they conditional policies, constraints, policy types, or audit capabilities, are covered in this book with genuine examples that administrators might come across. By the end, SELinux System Administration will have taught you how to configure your Linux system to be more secure, powered by a formidable mandatory access control.
Table of Contents (13 chapters)

Summary


SELinux maps Linux users onto SELinux users and defines the roles that a user is allowed to be in through the SELinux user definitions. We learned how to manage those mappings and the SELinux users with the semanage application and were able to grant the right roles to the right people.

We also saw how the same commands are used to grant proper sensitivity to the user and how we can describe these levels in the setrans.conf file. We used the chcat tool to do most of the category-related management activities.

After assigning roles to the users, we saw how to jump from one role to another using newrole, sudo, runcon, and run_init. We ended this chapter with the important insight on how SELinux integrates in the Linux authentication process and how it implements application-specific contexts.

In the next chapter, we will learn to manage the labels on files and processes and see how we can query the SELinux policy rules.