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

Types, permissions, and constraints


Now that we know more about types (both for processes as well as files and other resources), let's look into how these are used in the SELinux policy in more detail.

Understanding type attributes

We have discussed the sesearch application already and how it can be used to query the current SELinux policy. Let's look again at the process transitions:

$ sesearch -s initrc_t -t httpd_t -c process -p transition -A 
Found 1 semantic av rules: 
   allow initrc_domain daemon : process transition ; 

Even though we asked for the rules related to the initrc_t source domain and the httpd_t target, we get a rule back for the initrc_domain source domain and the daemon target. What sesearch did here was show us how the requested permission is allowed by SELinux, but through attributes assigned to the initrc_t and httpd_t types.

Type attributes in SELinux are used to group multiple types and assign privileges to those groups rather than having to assign the...