On Mon, Feb 04, 2019 at 10:10:05AM +0000, Daniel P. Berrangé wrote: > On Mon, Feb 04, 2019 at 12:09:04PM +1100, David Gibson wrote: > > On Sat, Feb 02, 2019 at 12:23:58AM +0530, P J P wrote: > > > From: Prasad J Pandit <p...@fedoraproject.org> > > > > > > On ppc hosts, hypervisor shares following system attributes > > > > > > - /proc/device-tree/system-id > > > - /proc/device-tree/model > > > > > > with a guest. This could lead to information leakage and misuse.[*] > > > Add machine attributes to control such system information exposure > > > to a guest. > > > > > > [*] https://wiki.openstack.org/wiki/OSSN/OSSN-0028 > > > > > > Reported-by: Daniel P. Berrangé <berra...@redhat.com> > > > Fix-suggested-by: Daniel P. Berrangé <berra...@redhat.com> > > > Signed-off-by: Prasad J Pandit <p...@fedoraproject.org> > > > > Hm. This seems like it might be overkill. I mean, obviously we need > > to not leak that host information, but it's not clear we really need > > these properties at all. They're not specified in PAPR (contrary to > > my previous guess) and it's not clear what actually uses them. > > > > I'm wondering if we can just ditch them entirely, or at least make > > them default to not present without regard to machine version. > > > > Yes, that's technically a compatibility breaking change, but it's hard > > to see anything that actually relied on these as not being broken > > already, so I think that's actually a fair trade off for the security > > improvement here. > > We cannot assume that no one is using it. > > In fact this issue came to light precisely because a person on IRC > was asking why x86 couldn't provide the same info as PPC, because > they found it useful on PPC.
"Found it useful" is not the same as actually relying on. > So we will definitely break people if we remove this from existing > VMs. I don't think that follows from the information you've presented so far. -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson
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