Book Image

SELinux System Administration. - Second Edition

Book Image

SELinux System Administration. - Second Edition

Overview of this book

Do you have the crucial job of protecting your private and company systems from malicious attacks and undefined application behavior? Are you looking to secure your Linux systems with improved access controls? Look no further, intrepid administrator! This book will show you how to enhance your system’s secure state across Linux distributions, helping you keep application vulnerabilities at bay. This book covers the core SELinux concepts and shows you how to leverage SELinux to improve the protection measures of a Linux system. You will learn the SELinux fundamentals and all of SELinux’s configuration handles including conditional policies, constraints, policy types, and audit capabilities. These topics are paired with genuine examples of situations and issues you may come across as an administrator. In addition, you will learn how to further harden the virtualization offering of both libvirt (sVirt) and Docker through SELinux. By the end of the book you will know how SELinux works and how you can tune it to meet your needs.
Table of Contents (16 chapters)
SELinux System Administration - Second Edition
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface

Handling device files


Linux has had a long history of device managers. Initially, administrators needed to make sure that the device nodes were already present on the file system (/dev was part of the persisted file system). Gradually, more dynamic approaches were used for device management.

Nowadays, device files are managed through a combination of a pseudo file system (devtmpfs) and a user space device manager called udev. This device manager has been merged in systemd as well, becoming systemd-udevd.

Note

There are projects, such as eudev, which provide udev functionality without requiring systemd to be installed and enabled on the system.

The device manager listens on a kernel socket for kernel events. These events inform the device manager about detected or plugged-in devices (or the removal of such devices) and allow the device manager to take appropriate action. For udev, these actions are defined in udev rules.

Using udev rules

The main configuration of udev is handled through udev rules...