Messages in this thread | | | Date | Mon, 6 Apr 2020 10:47:38 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH 1/2] x86/boot/compressed/64: Remove .bss/.pgtable from bzImage |
| |
On Mon, Apr 06, 2020 at 09:32:47AM +0200, Ard Biesheuvel wrote: > The EFI handover protocol strikes again :-( > > It seems we did not include any guidance in the documentation in > Documentation/x86/boot.rst regarding zero-initializing BSS, and come > to think of it, we don't include any other requirements either, i.e., > regarding placement wrt section alignment etc. This is a serious bug. > Even though EFI usually lays out PE/COFF images in files the exact way > they appear in memory, this is not actually required by the spec. Most > notably, the virtual size can be smaller than the file size, and the > loader is expected to zero-initialize the difference as well.
Is that expectation stated explicitly somewhere?
> Since the EFI handover protocol should be considered deprecated at > this point (and is never going to be supported in upstream GRUB > either, for instance), I would recommend the systemd-boot developers > to start looking into deprecating this as well, and switch to the > ordinary PE/COFF entry point, and use the new initrd callback protocol > for initrd loading.
Any pointers to that new initrd callback protocol?
In any case, I'd really appreciate a patch to boot.rst formulating those requirements so that they're written down and people can find them.
> On the Linux/x86 side, we should at least add some code to the EFI > handover protocol entry point to zero initialize BSS, and ensure that > it is either not needed in other places, or add the code to deal with > those as well.
Sounds like a simple fix, if that would fix it.
Thx.
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
| |