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

Using and understanding the policy macros

Across the various SELinux policy definitions, we have come across macros that are not tied to a specific SELinux policy module. These are support macros, available inside the policy/support/*.spt files.

The most common macros are those declared inside the obj_perm_sets.spt file (which group common permissions for the same class in a single definition) and the *_patterns.spt files (which group permissions across different classes in a single definition).

Making use of single-class permission groups

Single-class permission groups allow developers to ignore possible extensions of the SELinux supported permissions as time goes by. For instance, if you want to allow a domain to execute a certain resource, it is most often not enough to allow the execute permission. You also need the open and read permissions (as otherwise, the domain cannot read the executable) and the map permission (to allow mapping the file in memory).

If you were...