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 16

  1. The SELinux Common Intermediate Language (CIL) is not an extension to SELinux that can be easily removed. It is at the heart of SELinux policy development and support, although mainly under the hood: all SELinux policy modules that are loaded on the system are first converted into CIL before actually being loaded in memory.

    The CIL format is the only format used to interact with the Linux kernel and the SELinux subsystem. Because it is used as part of the SELinux user space utilities, it is not always as obvious to administrators or developers, but it is definitely a core component within SELinux.

  2. No, it is not mandatory, but is recommended. The attribute is used to refer to types and roles in a modular fashion, and to ensure that these references are valid. CIL internally requires types and roles to be defined before they are used, and without using an attribute to force such declarations, the order of loading modules might result in failures.

    While other attributes...