45 lines
1.9 KiB
Diff
45 lines
1.9 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Daniel Axtens <dja@axtens.net>
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Date: Mon, 6 Oct 2025 12:55:03 +0530
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Subject: [PATCH] docs/grub: Document signing GRUB under UEFI
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Before adding information about how GRUB is signed with an appended
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signature scheme, it's worth adding some information about how it
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can currently be signed for UEFI.
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Signed-off-by: Daniel Axtens <dja@axtens.net>
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Signed-off-by: Sudhakar Kuppusamy <sudhakar@linux.ibm.com>
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Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
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Reviewed-by: Avnish Chouhan <avnish@linux.ibm.com>
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Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
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---
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docs/grub.texi | 15 +++++++++++++++
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1 file changed, 15 insertions(+)
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diff --git a/docs/grub.texi b/docs/grub.texi
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index 2d6d73a..e08aaf5 100644
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--- a/docs/grub.texi
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+++ b/docs/grub.texi
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@@ -6912,6 +6912,21 @@ which increases the risk of password leakage during the process. Moreover, the
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superuser list must be well maintained, and the password used cannot be
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synchronized with LUKS key rotation.
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+@node Signing GRUB itself
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+@section Signing GRUB itself
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+To ensure a complete secure-boot chain, there must be a way for the code that
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+loads GRUB to verify the integrity of the core image.
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+This is ultimately platform-specific and individual platforms can define their
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+own mechanisms. However, there are general-purpose mechanisms that can be used
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+with GRUB.
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+@section Signing GRUB for UEFI secure boot
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+On UEFI platforms, @file{core.img} is a PE binary. Therefore, it can be signed
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+with a tool such as @command{pesign} or @command{sbsign}. Refer to the
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+suggestions in @pxref{UEFI secure boot and shim} to ensure that the final
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+image works under UEFI secure boot and can maintain the secure-boot chain. It
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+will also be necessary to enroll the public key used into a relevant firmware
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+key database.
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+
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@node Platform limitations
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@chapter Platform limitations
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