Re: some questions

[Thor Lancelot Simon <tls%rek.tjls.com@localhost>]

On Sat, Jan 07, 2006 at 11:54:55AM +0100, Manuel Bouyer wrote:
> On Sat, Jan 07, 2006 at 08:59:38AM +0100, Pavel Cahyna wrote:
> > On Sat, Jan 07, 2006 at 05:44:50AM +0100, Manuel Bouyer wrote:
> > > On Sat, Jan 07, 2006 at 01:14:49AM +0100, Pavel Cahyna wrote:
> > > > Why?
> > > > 
> > > > if you have root in a domU, you don't need a kernel bug to use DMA, 
> > > > which
> > > > opens the door to dom0.
> > > 
> > > How do you get access to the DMA register if you don't take control over
> > > the kernel ?
> > 
> > i386_iopl ?
> 
> int
> i386_iopl(l, args, retval)
> {
> [...]
>       if (securelevel > 1)

Securelevel > 1?  That test should be securelevel >= 1.  It's a serious
bug if it's not.

-- 
  Thor Lancelot Simon                                        
tls%rek.tjls.com@localhost

  "We cannot usually in social life pursue a single value or a single moral
   aim, untroubled by the need to compromise with others."      - H.L.A. Hart