On Mon, 30 Mar 2020 at 20:24, Ard Biesheuvel <ardb@xxxxxxxxxx> wrote:
>
> On Mon, 30 Mar 2020 at 20:12, Michael Kelley <mikelley@xxxxxxxxxxxxx> wrote:
> >
> > From: Ard Biesheuvel <ardb@xxxxxxxxxx> Sent: Monday, March 30, 2020 12:51 AM
> > >
> > > On Mon, 30 Mar 2020 at 09:50, Ard Biesheuvel <ardb@xxxxxxxxxx> wrote:
> > > >
> > > > On Mon, 30 Mar 2020 at 09:47, Leif Lindholm <leif@xxxxxxxxxxxx> wrote:
> > > > >
> > > > > On Sat, Mar 28, 2020 at 21:58:09 +0100, Ard Biesheuvel wrote:
> > > > > > Commit 9f9223778ef3 ("efi/libstub/arm: Make efi_entry() an ordinary
> > > > > > PE/COFF entrypoint") did some code refactoring to get rid of the
> > > > > > EFI entry point assembler code, and in the process, it got rid of the
> > > > > > assignment of image_addr to the value of _text. Instead, it switched
> > > > > > to using the image_base field of the efi_loaded_image struct provided
> > > > > > by UEFI, which should contain the same value.
> > > > > >
> > > > > > However, Michael reports that this is not the case: older GRUB builds
> > > > > > corrupt this value in some way, and since we can easily switch back to
> > > > > > referring to _text to discover this value, let's simply do that.
> > > > >
> > > > > It is not clear to me how "older GRUB builds" would differ here.
> > > > > I think more investigation is needed before making that claim.
> > > > > My suspicion is that some (old) version of non-upstream, shim-enabled
> > > > > distro-specific build is playing a part.
> > > > >
> > > > > So, do we have the option for more detailed investigations, or can we
> > > > > vague the claim up to say "some GRUB builds seen in the wild, based
> > > > > on an upstream 2.02" or suchlike?
> > > > >
> > > >
> > > > I've queued a fix that prints a nastygram if the value deviates from
> > > > the expected one. Let's see if this triggers any reports.
> > >
> > > (/me looks at context)
> > >
> > > *This* is the fix that prints a nastygram.
> >
> > FWIW, I pulled the BOOTAA64.EFI and grubaa64.efi files from CentOS 7.6
> > and CentOS 8.0 binary packages and tested both in my Hyper-V VM.
> > Using strings | grep '2\.' to get version info, the CentOS 7.6 grubaa64.efi
> > shows:
> >
> > User-Agent: GRUB 2.02~beta2
> >
> > The CentOS 8.0 grubaa64.efi shows:
> >
> > User-Agent: GRUB 2.03
> >
> > Both versions produce the FIRMWARE BUG warning when using Ard's
> > latest patch. I'll assume the equivalent RHEL versions are the same.
> > So we've got official distro releases that show the problem.
> >
> > As reported earlier, the BOOTAA64.EFI and grubaa64.efi from a
> > Debian release (not exactly sure which one) do not produce the
> > FIRMWARE BUG warning. The grubaa64.efi reports as 2.04-4.
> >
>
> Thanks a lot Michael, that is really helpful.
I could not reproduce the issue with Debian Stretch's
2.02~beta3-5+deb9u2, so it does appear to be RedHat's value add that
is to blame here.
@Laszlo: TL;DR RedHat's GRUB for arm64 appears to clobber the
image_base field of the efi_loaded_image struct passed to the kernel.
Could you please recommend a way to report this?
