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

Applying custom XSM policies

Xen also allows administrators to build and use their own, custom policy.

The default policy for Xen is available inside the tools/flask/policy directory within the Xen build directory. For instance, the policy rules for the dom0 guest are available inside modules/dom0.te.

Important note

Adjusting the Xen XSM policy is beyond the scope of this chapter. You will find instructions on how to create SELinux policies using the reference policy-style method in Chapter 15, Using the Reference Policy. The Xen XSM policy is based upon this style.

Building a custom policy is a matter of updating these files (make a backup before you do) and then rebuilding the policy itself:

$ make

The result of the policy build is a new xenpolicy-4.13.1 file. This file can be loaded directly using the xl loadpolicy command:

# xl loadpolicy /path/to/xenpolicy-4.13.1

This command is similar to the flask-loadpolicy command:

# flask-loadpolicy /path/to/xenpolicy...