Messages in this thread | | | Date | Thu, 26 Jan 2023 15:43:59 +0000 | From | Daniel P. Berrangé <> | Subject | Re: Linux guest kernel threat model for Confidential Computing |
| |
On Thu, Jan 26, 2023 at 03:23:34PM +0100, Richard Weinberger wrote: > On Wed, Jan 25, 2023 at 3:22 PM Daniel P. Berrangé <berrange@redhat.com> wrote: > > Any virtual device exposed to the guest that can transfer potentially > > sensitive data needs to have some form of guest controlled encryption > > applied. For disks this is easy with FDE like LUKS, for NICs this is > > already best practice for services by using TLS. Other devices may not > > have good existing options for applying encryption. > > I disagree wrt. LUKS. The cryptography behind LUKS protects persistent data > but not transport. If an attacker can observe all IO you better > consult a cryptographer. > LUKS has no concept of session keys or such, so the same disk sector will > always get encrypted with the very same key/iv.
Yes, you're right, all the FDE cipher modes are susceptible to time based analysis of I/O, so very far from ideal. You'll get protection for your historically written confidential data at the time a VM host is first compromised, but if (as) they retain long term access to the host, confidentiality is increasingly undermined the longer they can observe the ongoing I/O.
With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
| |