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 9

  1. The unique idea that sVirt has that differentiates it from a more standard SELinux configuration is to use SELinux's MCS support to the next level. By randomly assigning two categories to a guest, sVirt can deal with isolating thousands of guests even when far fewer categories are available to use.
  2. The two main security measures that SELinux implements on top of the virtualization layer are as follows:

    - Intra-guest isolation, ensuring that guests cannot attack one another, or leak information between guests

    - Guest/host isolation, ensuring that guests can only access and interact with the resources on the host that are needed

    While both are, of course, also implemented within the hypervisor code, any design flaw could lead to high-impact problems. By implementing these isolations within SELinux, we use the strength of the SELinux subsystem as an independent (and much more flexible) access control system.

  3. The virt_image_t label is used for guest images when...