Re: [Xen-devel] [PATCH 21/22] libxc: range checks in xc_dom_p2m_host and _guest

[Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>]

George Dunlap writes ("Re: [Xen-devel] [PATCH 21/22] libxc: range checks in 
xc_dom_p2m_host and _guest"):
> On Tue, Jun 11, 2013 at 7:21 PM, Ian Jackson <ian.jackson@xxxxxxxxxxxxx> 
> wrote:
> > These functions take guest pfns and look them up in the p2m.  They did
> > no range checking.
> >
> > However, some callers, notably xc_dom_boot.c:setup_hypercall_page want
> > to pass untrusted guest-supplied value(s).  It is most convenient to
> > detect this here and return INVALID_MFN.
> >
> > This is part of the fix to a security issue, XSA-55.
> >
> > Signed-off-by: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
> > Cc: Tim Deegan <tim@xxxxxxx>
> 
> I've taken a look at where things get returned here, and it seems like
> they should all be OK with INVALID_MFN.

Good.  Does that mean that we should promote the check to be done in
the shadow_enabled case too ?

Ian.

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