Chapter 9

1. The unique idea that sVirt has that differentiates it from a more standard SELinux configuration is to use SELinux's MCS support to the next level. By randomly assigning two categories to a guest, sVirt can deal with isolating thousands of guests even when far fewer categories are available to use.
2. The two main security measures that SELinux implements on top of the virtualization layer are as follows:

   - Intra-guest isolation, ensuring that guests cannot attack one another, or leak information between guests

   - Guest/host isolation, ensuring that guests can only access and interact with the resources on the host that are needed

   While both are, of course, also implemented within the hypervisor code, any design flaw could lead to high-impact problems. By implementing these isolations within SELinux, we use the strength of the SELinux subsystem as an independent (and much more flexible) access control system.

3. The virt_image_t label is used for guest images when...