Book Image

SELinux System Administration, Third Edition - Third Edition

By : Sven Vermeulen
Book Image

SELinux System Administration, Third Edition - Third Edition

By: Sven Vermeulen

Overview of this book

Linux is a dominant player in many organizations and in the cloud. Securing the Linux environment is extremely important for any organization, and Security-Enhanced Linux (SELinux) acts as an additional layer to Linux system security. SELinux System Administration covers basic SELinux concepts and shows you how to enhance Linux system protection measures. You will get to grips with SELinux and understand how it is integrated. As you progress, you’ll get hands-on experience of tuning and configuring SELinux and integrating it into day-to-day administration tasks such as user management, network management, and application maintenance. Platforms such as Kubernetes, system services like systemd, and virtualization solutions like libvirt and Xen, all of which offer SELinux-specific controls, will be explained effectively so that you understand how to apply and configure SELinux within these applications. If applications do not exert the expected behavior, you’ll learn how to fine-tune policies to securely host these applications. In case no policies exist, the book will guide you through developing custom policies on your own. By the end of this Linux book, you’ll be able to harden any Linux system using SELinux to suit your needs and fine-tune existing policies and develop custom ones to protect any app and service running on your Linux systems.
Table of Contents (22 chapters)
1
Section 1: Using SELinux
8
Section 2: SELinux-Aware Platforms
14
Section 3: Policy Management

Chapter 12: Tuning SELinux Policies

Until now, we have been working with an existing SELinux policy by tuning our system to deal with the proper SELinux contexts and assigning the right labels to files, directories, and even network ports. We've learned that the behavior that SELinux enforces is defined within the policies. To fine-tune the policy enforcement rules, we have already briefly covered SELinux booleans.

It's time we look into SELinux booleans in more detail, learning how to look up the impact booleans have. Within this chapter, we then consider SELinux policy modules themselves and what options administrators have when dealing with these modules. Finally, we will look at how to update or even replace existing policies.

In this chapter, we're going to cover the following main topics:

  • Working with SELinux booleans
  • Handling policy modules
  • Replacing and updating existing policies