Book Image

SELinux System Administration - Second Edition

By : Sven Vermeulen
Book Image

SELinux System Administration - Second Edition

By: Sven Vermeulen

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

Other policy analysis


Two additional tools (sediff and sepolicy) exist that provide some insight into the current SELinux policy. The next two subsections cover these in more detail.

Comparing policies with sediff

The sediff tool, part of the setools package, looks at the differences between two policy files and reports the differences to the user. It does not provide patch-like capabilities (which the regular diff does) but is powerful to find and analyze small differences.

A common use case for the sediff tool is to validate that a source-built policy file is the same as the distribution-provided binary policy file. Administrators can then be certain that the source code they used to build a policy file is the same as that used by the distribution to generate the provided policy.

Its basic usage is simply to provide the two binary files:

$ sediff distro-policy.30 selfbuilt-policy.30 
Policy Properties (0 Modified) 
 
Booleans (0 Added, 0 Removed, 1 Modified) 
  Modified...