* Laszlo Ersek (lersek@redhat.com) wrote:
On 01/07/21 18:33, Dr. David Alan Gilbert wrote:
in some ways you're trading off host-guest security against guest security there.
This is a great way to put it IMO; the question is whether SB -- normally, a barrier between guest components -- buys the guest owner any actual security in this use case. If the guest owner controls both the guest firmware and the guest OS completely, there likely is no threat that the guest OS might somehow undermine the guest firmware (e.g., get hacked and install a permanent UEFI rootkit on the UEFI system partition, or whatever).
It doesn't help if the guest gets compromised by something it's doing; you can imagine a guest-owner who runs a VM that processes externally provided data; they want protection against the cloud-vendor (hence SEV), but they know there's a chance that while processing externally provided data they could get compromised; SB would give them some protection.
TBH the *intersections* of these security technologies / threat models are a bit mind-boggling, to me anyway.
Heck yes, well and truly boggled. Dave
Laszlo -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK