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

Adding user-level policies

If we want to create custom user and role policies, then the most confusing choice is the choice of user template to pick. This template creates a role and user domain with a specific purpose in mind, and grants a number of permissions by default:

Figure 15.1 – Relationship between user domain templates

The most common templates to pick for user/role policies are the following:

  • userdom_restricted_user_template() for (by default) unprivileged end user roles.
  • userdom_admin_user_template() for (by default) highly privileged end user roles.

The other templates can be used as well, especially if more fine-grained controls over the roles and user domains are needed. Note, however, that the privileges assigned by the templates are mentioned as by default. If we want to create a role and user domain for administrating a specific service, then we do not want to use userdom_admin_user_template(), as this will grant...