Re: [Qemu-devel] Virtio-net drivers immune to Nethammer?

[Dr. David Alan Gilbert]

* Michael S. Tsirkin (address@hidden) wrote:
> On Fri, Jun 01, 2018 at 01:15:44PM +0000, procmem wrote:
> > 
> > 
> > Stefan Hajnoczi:
> > > On Mon, May 21, 2018 at 11:24:43PM +0000, procmem wrote:
> > >> Hi I'm a privacy distro maintainer investigating the implications of the
> > >> newly published nethammer attack [0] on KVM guests particularly the
> > >> virtio-net drivers. The summary of the paper is that rowhammer can be
> > >> remotely triggered by feeding susceptible* network driver crafted
> > >> traffic. This attack can do all kinds of nasty things such as modifying
> > >> SSL certs on the victim system.
> > >>
> > >> * Susceptible drivers are those relying on Intel CAT, uncached memory or
> > >> the clflush instruction.
> > >>
> > >> My question is, do virtio-net drivers do any of these things?
> > > I have CCed Michael Tsirkin and Jason Wang, the virtio maintainers.
> > > 
> > >> ***
> > >>
> > >> [0] https://arxiv.org/abs/1805.04956
> > >>
> > >>
> > >>
> > 
> > Thanks :) I thought my message was forgotten
> 
> 
> I don't think virtio is using either of these.
> 
> Linux does support CAT AFAIK but it has nothing to do with virtio.

Isn't the idea to misuse CAT to detect something about access patterns;
so it's not about it actually being related?

Dave

> -- 
> MST
> 
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK