Re: [RFC][PATCH 06/45] msix: Prevent bogus mask updates on MMIO accesses

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Mon, Oct 17, 2011 at 02:07:10PM +0200, Jan Kiszka wrote:
> On 2011-10-17 13:57, Michael S. Tsirkin wrote:
> > On Mon, Oct 17, 2011 at 01:23:46PM +0200, Jan Kiszka wrote:
> >> On 2011-10-17 13:10, Michael S. Tsirkin wrote:
> >>> On Mon, Oct 17, 2011 at 11:27:40AM +0200, Jan Kiszka wrote:
> >>>> Only accesses to the MSI-X table must trigger a call to
> >>>> msix_handle_mask_update or a notifier invocation.
> >>>>
> >>>> Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
> >>>
> >>> Why would msix_mmio_write be called on an access
> >>> outside the table?
> >>
> >> Because it handles both the table and the PBA.
> > 
> > Hmm. Interesting. Is there a bug in how we handle PBA
> > updates then? If yes I'd like a separate patch for that
> > to apply to the stable tree.
> 
> I first thought it was a serious bug, but it just triggers if the guest
> write to PBA (which is very uncommon) and that actually triggers any
> spurious out-of-bounds vector injection. Highly unlikely.

Yes guests don't really use PBA ATM. But is there something
bad a malicious guest can do? For example, what if
msix_clr_pending gets invoked with this huge vector value?

It does seem serious ...


> > 
> > BTW, this code will go away if PBA can get stored separately?
> 
> Hmm - yeah, true. Likely it's moot to discuss this change then.
> 
> Jan
> 
> -- 
> Siemens AG, Corporate Technology, CT T DE IT 1
> Corporate Competence Center Embedded Linux
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html


[Index of Archives]     [KVM ARM]     [KVM ia64]     [KVM ppc]     [Virtualization Tools]     [Spice Development]     [Libvirt]     [Libvirt Users]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite Questions]     [Linux Kernel]     [Linux SCSI]     [XFree86]
  Powered by Linux