Re: [XEN PATCH v2] efi: Use Shim's LoadImage to verify the Dom0 kernel

["Marek Marczykowski-Górecki" <marmarek@invisiblethingslab.com>]

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On Tue, Sep 02, 2025 at 05:00:52PM +0200, Jan Beulich wrote:
> On 02.09.2025 16:44, Gerald Elder-Vass wrote:
> > +        else
> > +        {
> > +            status = efi_bs->LocateProtocol(&shim_lock_guid, NULL, (void **)&shim_lock);
> > +            if ( EFI_ERROR(status) )
> > +                PrintErrMesg(L"Failed to locate SHIM_LOCK protocol", status);
> 
> This is a behavioral change not justified in the description. Imo, if
> the original code was wrong, that would want to be a separate change
> anyway, so right here you want to retain original behavior. Simply
> consider the case of a shim-free boot, where neither of the two
> protocols would be available.

Yes, as commented by Yann on v1, this change as is seems to break
shim-free boot (well, technically UKI is shim-free and remain working,
but you know what I mean). That needs to remain working, even if only in
SecureBoot-free case.

-- 
Best Regards,
Marek Marczykowski-Górecki
Invisible Things Lab

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