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    SubjectRe: Linux guest kernel threat model for Confidential Computing
    * Richard Weinberger (richard.weinberger@gmail.com) wrote:
    > On Thu, Jan 26, 2023 at 3:58 PM Dr. David Alan Gilbert
    > <dgilbert@redhat.com> wrote:
    > >
    > > * Richard Weinberger (richard.weinberger@gmail.com) 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.
    > >
    > > Are you aware of anything that you'd use instead?
    >
    > Well, I'd think towards iSCSI over TLS to protect the IO transport.

    Yeh, that's not entirely crazy for VMs which tend to come off some
    remote storage system.

    > > Are you happy with dm-verity for protection against modification?
    >
    > Like LUKS (actually dm-crypt) the crypto behind is designed to protect
    > persistent data not transport.
    > My fear is that an attacker who is able to observe IOs can do bad things.

    Hmm, OK, I'd assumed dm-crypt was OK since it's more hashlike and
    unchanging.

    Dave

    --
    Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK

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