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 11

  1. The machinectl command does not allow administrators to change the SELinux type of the running containers. This results in all containers running by default under an unconfined domain, whereas we want confined domains to be used—preferably even with sVirt support so that containers cannot influence one another either.
  2. When a container is launched with a location mapping, we should use the :Z option (in case of a private mapping) or the :z option (in case of a shared mapping) to ensure that the resources are relabeled with a container-accessible SELinux type:
    # podman run -dit --name postgresql-test -v /srv/db/postgresql-test:/bitnami/postgresql:Z -p 5432:5432 postgresql

    Without this option, the label of the resource remains untouched, which generally means that the container runtime cannot access the resource at all.

  3. We can use the udica application to generate a custom policy. The application uses the information that is provided from a podman inspect...