Book Image

SELinux System Administration. - Second Edition

Book Image

SELinux System Administration. - Second Edition

Overview of this book

Do you have the crucial job of protecting your private and company systems from malicious attacks and undefined application behavior? Are you looking to secure your Linux systems with improved access controls? Look no further, intrepid administrator! This book will show you how to enhance your system’s secure state across Linux distributions, helping you keep application vulnerabilities at bay. This book covers the core SELinux concepts and shows you how to leverage SELinux to improve the protection measures of a Linux system. You will learn the SELinux fundamentals and all of SELinux’s configuration handles including conditional policies, constraints, policy types, and audit capabilities. These topics are paired with genuine examples of situations and issues you may come across as an administrator. In addition, you will learn how to further harden the virtualization offering of both libvirt (sVirt) and Docker through SELinux. By the end of the book you will know how SELinux works and how you can tune it to meet your needs.
Table of Contents (16 chapters)
SELinux System Administration - Second Edition
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface

SELinux booleans


One of the methods of manipulating SELinux policies is by toggling SELinux booleans. Ever since Chapter 2, Understanding SELinux Decisions and Logging, in which 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 administrators use SELinux booleans to manage parts of the policy that are not always needed (or wanted) but still have a common use case.

Listing SELinux booleans

An overview of SELinux booleans can be obtained using the semanage command with the boolean option. On a regular system, we can easily find over a hundred SELinux booleans, so it is necessary to filter out the description of the boolean we need:

# semanage boolean -l | grep policyload 
secure_mode_policyload   (off, off)

Boolean to determine whether the system permits loading policy, setting enforcing mode, and changing boolean values. Set this...