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

Modifying file contexts


We now know how to set SELinux contexts, both directly through tools such as chcon as well as through the restorecon application, which queries the SELinux context list to know what context a file should have. But restorecon is not the only application that considers this context list.

Using setfiles, rlpkg, and fixfiles

Using semanage fcontext and restorecon is the preferred method for changing file contexts, but other tools exist that impact file contexts on a system.

The setfiles application is an older one, which requires the path to the context list file itself in order to reset contexts. Although it is often used under the hood of other applications, most administrators do not need to call setfiles directly anymore:

# setfiles /etc/selinux/targeted/contexts/files/file_contexts /srv/www

Another set of tools are the rlpkg (Gentoo) and fixfiles (RHEL) applications. Both these applications have a nice feature: they can be used to reset the contexts of the files of...