Re: [Xen-ia64-devel] [rfc 13/15] Kexec: offsets for EFI runtime regions

[Horms <horms@xxxxxxxxxxxx>]

On Sat, Sep 08, 2007 at 06:06:30AM +0200, Tristan Gingold wrote:
> On Fri, Aug 17, 2007 at 03:50:55PM +0900, Simon Horman wrote:
> > This is used by paches that move the EFI runtime regions into what is
> > normally guest space.  A description of why this mapping is made is
> > included in the patch that makes the mapping.
> [...]
> > +/* In order for Kexec between Xen and Linux to work EFI needs
> > + * to be mapped into the same place by both. It seems most convenient
> > + * to make Xen do the dirty work here */
> > +#define __IA64_EFI_UNCACHED_OFFSET 0xc000000000000000UL
> > +#define __IA64_EFI_CACHED_OFFSET   0xf000000000000000UL
> 
> Hi,
> 
> sorry or this late comment but doesn't this code creates a security hole ?
> EFI_UNCACHED_OFFSET area will be visible inside vti domains as its virtual
> address is valid in these domains.

Hi Tristan,

I think that you have a good point there.

Currently the code is checking psr.cpl to make sure that it is 0,
and thus deny access to (non-vti?) domains. Is a similar check possible
for vti domains, or is the problem a little deeper?

-- 
Horms
  H: http://www.vergenet.net/~horms/
  W: http://www.valinux.co.jp/en/


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