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

Integrating SEPostgreSQL into the network

When we use the sepgsql module in PostgreSQL, all database sessions need to have a security context associated with them. While for local communications (which use Unix domain sockets) this context is readily available, networked sessions (which are the most common) do not automatically have a context set.

If the system does not participate in a labeled networking setup, as we saw in Chapter 5, Controlling Network Communications, interaction with the database will fail:

$ psql -U testuser -h ppubssa3ed db_test
psql: FATAL:  SELinux: unable to get peer label: Protocol not available

To resolve this, the recommended approach is to start using labeled IPSec. However, we can also use NetLabel to introduce fallback labeling where needed.

Creating a fallback label for remote sessions

With Linux's NetLabel and CIPSO support (as seen in Chapter 5, Controlling Network Communications) we can introduce both fallback labeling...