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 13: Analyzing Policy Behavior

Although SELinux policies enforce the mandatory access controls and application behavior on a system, knowing how a policy will act upfront is useful for administrators to perform assessments and root cause analysis activities.

Throughout this chapter, we will learn how to query the SELinux policy in depth, using a multitude of tools to query process transitions, analyze information flows, and compare policies. We will consider the apol tool, a graphical interface with which we can perform several analyses on a policy, as well as command-line tools such as sesearch, sedta, seinfoflow, and sepolicy. Finally, we will use sediff to compare policies.

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

  • Performing single-step analysis
  • Investigating domain transitions
  • Analyzing information flow
  • Comparing policies