Chapter 16. Security for virtualization

16.1. Storage security issues
16.2. SELinux and virtualization
16.3. SELinux
16.4. Virtualization firewall information

When deploying virtualization technologies on your corporate infrastructure, you must ensure that the host cannot be compromised. The host is a Red Hat Enterprise Linux system that manages the system, devices, memory and networks as well as all virtualized guests. If the host is insecure, all guests in the system are vulnerable. There are several ways to enhance security on systems using virtualization. You or your organization should create a Deployment Plan containing the operating specifications and specifies which services are needed on your virtualized guests and host servers as well as what support is required for these services. Here are a few security issues to consider while developing a deployment plan:

Run only necessary services on hosts. The fewer processes and services running on the host, the higher the level of security and performance.
Enable SELinux on the hypervisor. Read Section 16.2, “SELinux and virtualization” for more information on using SELinux and virtualization.
Use a firewall to restrict traffic to the host. You can setup a firewall with default-reject rules that will help secure the host from attacks. It is also important to limit network-facing services.
Do not allow normal users to access the host. The host is privileged, and granting access to unprivileged accounts may compromise the level of security.

16.1. Storage security issues

Administrators of virtualized guests can change the partitions the host boots in certain circumstances. To prevent this administrators should follow these recommendations:

The host should not use disk labels to identify file systems in the fstab file, the initrd file or used by the kernel command line. If less privileged users, especially virtualized guests, have write access to whole partitions or LVM volumes.

Guests should not be given write access to whole disks or block devices (for example, /dev/sdb). Use partitions (for example, /dev/sdb1) or LVM volumes.