Re: [Qemu-devel] QEMU - Security Research Questions

[Kevin Wolf <kwolf@redhat.com>]

Am 06.10.2016 um 10:27 hat Markus Armbruster geschrieben:
> Paolo Bonzini <pbonzini@redhat.com> writes:
> 
> > On 06/10/2016 02:10, Joey Connelly wrote:
> >> Hey QEMU dev group,
> >> I'm a graduate student at Boise State University working on my thesis
> >> involving Virtualization/Cloud Computing Security and I wanted to ask a few
> >> questions:
> >> 
> >> *[QUESTION#1.]* From within a guest KVM/QEMU process (qemu-system-x86_64
> >> -enable-kvm) can the VM invoke commands on its host - either through QEMU
> >> Monitor Console commands, or by some other means I'm unaware of?
> >> 
> >> *[QUESTION#**2.]* Can a host administrator running a guest KVM/QEMU process
> >> have QEMU Monitor Console commands invoked on that guest VM if *no*
> >> "-monitor" option was used?
> >>
> >> *[QUESTION#**3.]* If a host admin creates a KVM/QEMU process with the
> >> "qemu-system-x86_64 -enable-kvm -netdev tap,<...>" options is there a
> >> KVM/QEMU specific way to query the "tap,<...>" information later after the
> >> process has been created? (assuming your admin account maintains ring 0
> >> permissions)
> >
> > No to all three.
> 
> The pedantically correct answer to #2 would be "not easily": you'd have
> to play games with a debugger.

I think it's rather "it depends". If you don't actively disable it, the
default (i.e. running qemu-system-x86_64 without any parameters) gives
you an HMP monitor. You can use things like '-monitor none' or
'-nodefaults' to get rid of it.

By the way, Gerd, just 'qemu-system-x86_64 -nodefaults' gives me a GTK
window that contains only the menu bar and almost all options in the
"View" menu make it segfault.

Kevin