Messages in this thread | | | Date | Mon, 6 Apr 2020 13:20:42 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH 1/2] x86/boot/compressed/64: Remove .bss/.pgtable from bzImage |
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On Mon, Apr 06, 2020 at 11:11:21AM +0200, Ard Biesheuvel wrote: > Yes, it is in the PE/COFF specification. [0] > > The whole problem is that we are conflating 'loading a PE/COFF image' > with 'copying a PE/COFF image into memory', which are not the same > thing. It is not just the layout issue, we are running into other > problems with things like UEFI secure boot and TPM-based measured > boot, where the fact that omitting the standard LoadImage() boot > service (which takes care of these things under the hood) means that > you now have to do your own checks and measurements. These things are > literally all over the place at the moment, shim, GRUB, systemd-boot > etc, with no authoritative spec that describes which component should > be doing what.
Sounds to me like what LoadImage() does is what the authoritative spec should be. Perhaps we should write it down as "Do what LoadImage() does... " and then enumerate the requirements.
> Commit ec93fc371f014a6fb483e3556061ecad4b40735c has the background, but ...
Nice, I like the aspect of letting firmware do only a minimum amount of work. :)
> ... I'll look into updating the documentation as well.
Thanks!
> Note that this stuff is hot off the press, so there may be some issues > lurking (like this one) that we hadn't thought of yet.
Right.
> Actually, it may be sufficient to #define __efistub_global to > __section(.data) like we already do for ARM, to ensure that these > global flags are always initialized correctly. (I'll wait for Sergey > to confirm that the spurious enabling of the PCI DMA protection > resulting from this BSS issue is causing the boot regression)
Cool, but let's not jinx it. :-)
Thx.
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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