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

Working with SELinux booleans

One of the methods of manipulating SELinux policies is by toggling SELinux booleans. Ever since Chapter 2, Understanding SELinux Decisions and Logging, where we used the secure_mode_policyload boolean, these tunable settings have been popping up over the course of this book. With their simple ON/OFF state, they enable or disable parts of the SELinux policy. Policy developers and administrators use SELinux booleans to toggle parts of the policy that not all deployments always need to be active, but some still do.

These booleans are added to the policy based on feedback from, and with the help of, the community at large. By establishing which policy rules are necessary against those that are optional, SELinux developers can provide an SELinux policy that works for a majority of systems, even when the uses of these systems differ.

Listing SELinux booleans

An overview of SELinux booleans can be obtained by using the semanage command with the boolean...