On 9/1/19 8:38 AM, John S Gruber wrote:
From: "John S. Gruber" <[email protected]>

commit a90118c445cc ("x86/boot: Save fields explicitly, zero out everything
else") now zeros the secure boot information passed by the boot loader or
by the kernel's efi handover mechanism.

Include boot-params.secure_boot in the preserve field list.

Signed-off-by: John S. Gruber <[email protected]>
---

I noted a change in my computers between running signed 5.3-rc4 and 5.3-rc6
with signed kernels using the efi handoff protocol with grub. The kernel
log message "Secure boot enabled" becomes "Secure boot could not be
determined". The efi_main function in arch/x86/boot/compressed/eboot.c sets
this field early but it is subsequently zeroed by the above referenced commit
in the file arch/x86/include/asm/bootparam_utils.h

Applies to 5.3-rc6.


Hi,

The fix itself looks good, so you can add:

    Reviewed-by: John Hubbard <[email protected]>

...but note that the commit description should get a few tweaks:

1. Your description above is actually well-suited for the commit log,
so please add that in. Especially the symptoms are desirable to have
on record.

2. This should Cc: [email protected], because the whole thing
made it into -stable and those kernels need this fix.

3. Also need a Fixes tag:

Fixes: commit a90118c445cc ("x86/boot: Save fields explicitly, zero out everything 
else")

thanks,
--
John Hubbard
NVIDIA

  arch/x86/include/asm/bootparam_utils.h | 1 +
  1 file changed, 1 insertion(+)

diff --git a/arch/x86/include/asm/bootparam_utils.h
b/arch/x86/include/asm/bootparam_utils.h
index 9e5f3c7..981fe92 100644
--- a/arch/x86/include/asm/bootparam_utils.h
+++ b/arch/x86/include/asm/bootparam_utils.h
@@ -70,6 +70,7 @@ static void sanitize_boot_params(struct boot_params
*boot_params)
                        BOOT_PARAM_PRESERVE(eddbuf_entries),
                        BOOT_PARAM_PRESERVE(edd_mbr_sig_buf_entries),
                        BOOT_PARAM_PRESERVE(edd_mbr_sig_buffer),
+                       BOOT_PARAM_PRESERVE(secure_boot),
                        BOOT_PARAM_PRESERVE(hdr),
                        BOOT_PARAM_PRESERVE(e820_table),
                        BOOT_PARAM_PRESERVE(eddbuf),

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