[PATCH] efi/libstub: zboot: Round up image size to section alignment

[PATCH] efi/libstub: zboot: Round up image size to section alignment

[Ard Biesheuvel]

From: Ard Biesheuvel <ardb@kernel.org>

Oliver reports that some arm64 EFI boot images have a SizeOfImage field
in the PE header that is set to a value that is not a round multiple of
the image's section alignment, which violates the PE/COFF spec.

This turns out to be a problem in the zboot linker script, and so it
affects compressed EFI zboot images for all architectures, not only
arm64. Uncompressed arm64 images built with an EFI stub are fine, as
those are rounded up to 64k already.

So fix this by bumping the zboot _end marker to the next 4k boundary .

Reported-by: Oliver Smith-Denny <osde@linux.microsoft.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 drivers/firmware/efi/libstub/zboot.lds | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/firmware/efi/libstub/zboot.lds b/drivers/firmware/efi/libstub/zboot.lds
index 367907eb7d86..a785c0123749 100644
--- a/drivers/firmware/efi/libstub/zboot.lds
+++ b/drivers/firmware/efi/libstub/zboot.lds
@@ -45,7 +45,7 @@ SECTIONS
 
 	.bss : {
 		*(.bss* .init.bss*)
-		_end = ALIGN(512);
+		_end = ALIGN(4096);
 		. = _end;
 	}
 
-- 
2.56.0.307.g5fe7bd680c-goog