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 3

  1. There is an intermediate step needed to associate a role with a Linux account, and that is the SELinux user. A Linux account (or login) is mapped to an SELinux user. The SELinux user is then mapped to one or more SELinux roles that that SELinux user can be in.

    If we want to assign an additional role to a Linux user, we need to add it to the SELinux role that that Linux account is mapped to. However, if more Linux accounts are mapped to the same SELinux user, then we first need to make sure that all these accounts are indeed allowed to use this role. If not, a dedicated SELinux user has to be created for the Linux account.

  2. Yes, the mappings are considered when a user logs in through a particular service. It is possible for administrators to tune the mappings to be dependent on the service, as seen in the Customizing logins toward services section.
  3. Most SELinux domains do not allow the SELinux user of a context to be changed. This allows the tracking of activities...