forked from pool/grub2
8ee92f5194
- Implement NV index mode for TPM 2.0 key protector 0001-protectors-Implement-NV-index.patch - Fall back to passphrase mode when the key protector fails to unlock the disk 0002-cryptodisk-Fallback-to-passphrase.patch - Wipe out the cached key cleanly 0003-cryptodisk-wipe-out-the-cached-keys-from-protectors.patch - Make diskfiler to look up cryptodisk devices first 0004-diskfilter-look-up-cryptodisk-devices-first.patch - Version bump to 2.12~rc1 * Added: - grub-2.12~rc1.tar.xz * Removed: - grub-2.06.tar.xz * Patch dropped merged by new version: - grub2-GRUB_CMDLINE_LINUX_RECOVERY-for-recovery-mode.patch - grub2-s390x-02-kexec-module-added-to-emu.patch - grub2-efi-chainloader-root.patch - grub2-Fix-incorrect-netmask-on-ppc64.patch - 0001-osdep-Introduce-include-grub-osdep-major.h-and-use-i.patch - 0002-osdep-linux-hostdisk-Use-stat-instead-of-udevadm-for.patch - 0002-net-read-bracketed-ipv6-addrs-and-port-numbers.patch - grub2-s390x-10-keep-network-at-kexec.patch - 0001-Fix-build-error-in-binutils-2.36.patch - 0001-emu-fix-executable-stack-marking.patch - 0046-squash-verifiers-Move-verifiers-API-to-kernel-image.patch - 0001-30_uefi-firmware-fix-printf-format-with-null-byte.patch - 0001-tpm-Pass-unknown-error-as-non-fatal-but-debug-print-.patch - 0001-Filter-out-POSIX-locale-for-translation.patch OBS-URL: https://build.opensuse.org/request/show/1105405 OBS-URL: https://build.opensuse.org/package/show/Base:System/grub2?expand=0&rev=458
67 lines
2.3 KiB
Diff
67 lines
2.3 KiB
Diff
From ac539a315495792cd75fe8ab1c474f26e0a78852 Mon Sep 17 00:00:00 2001
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From: Daniel Axtens <dja@axtens.net>
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Date: Sat, 15 Aug 2020 02:19:36 +1000
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Subject: [PATCH 06/23] docs/grub: Document signing grub with an appended
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signature
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Signing grub for firmware that verifies an appended signature is a
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bit fiddly. I don't want people to have to figure it out from scratch
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so document it here.
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Signed-off-by: Daniel Axtens <dja@axtens.net>
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---
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docs/grub.texi | 42 ++++++++++++++++++++++++++++++++++++++++++
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1 file changed, 42 insertions(+)
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--- a/docs/grub.texi
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+++ b/docs/grub.texi
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@@ -6606,6 +6606,48 @@
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will also be necessary to enrol the public key used into a relevant firmware
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key database.
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+@section Signing GRUB with an appended signature
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+
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+The @file{core.img} itself can be signed with a Linux kernel module-style
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+appended signature.
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+
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+To support IEEE1275 platforms where the boot image is often loaded directly
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+from a disk partition rather than from a file system, the @file{core.img}
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+can specify the size and location of the appended signature with an ELF
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+note added by @command{grub-install}.
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+
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+An image can be signed this way using the @command{sign-file} command from
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+the Linux kernel:
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+
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+@example
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+@group
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+# grub.key is your private key and certificate.der is your public key
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+
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+# Determine the size of the appended signature. It depends on the signing
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+# certificate and the hash algorithm
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+touch empty
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+sign-file SHA256 grub.key certificate.der empty empty.sig
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+SIG_SIZE=`stat -c '%s' empty.sig`
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+rm empty empty.sig
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+
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+# Build a grub image with $SIG_SIZE reserved for the signature
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+grub-install --appended-signature-size $SIG_SIZE --modules="..." ...
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+
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+# Replace the reserved size with a signature:
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+# cut off the last $SIG_SIZE bytes with truncate's minus modifier
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+truncate -s -$SIG_SIZE /boot/grub/powerpc-ieee1275/core.elf core.elf.unsigned
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+# sign the trimmed file with an appended signature, restoring the correct size
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+sign-file SHA256 grub.key certificate.der core.elf.unsigned core.elf.signed
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+
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+# Don't forget to install the signed image as required
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+# (e.g. on powerpc-ieee1275, to the PReP partition)
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+@end group
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+@end example
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+
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+As with UEFI secure boot, it is necessary to build in the required modules,
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+or sign them separately.
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+
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+
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@node Platform limitations
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@chapter Platform limitations
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