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Fix alignment of EFI binaries + inplace kernel decompression overwrite #20

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merged 3 commits into from
Aug 7, 2023
Merged

Fix alignment of EFI binaries + inplace kernel decompression overwrite #20

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8f41ea2
Fix alignment of EFI binaries
ShellCode33 Aug 6, 2023
afc1ae0
generate-efi : kernel is now the highest address to prevent inplace d…
ShellCode33 Aug 6, 2023
e69d393
Make it easier to follow calculations
maximbaz Aug 7, 2023
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28 changes: 17 additions & 11 deletions arch-secure-boot
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Original file line number Diff line number Diff line change
Expand Up @@ -72,31 +72,37 @@ case "$1" in
cat /boot/*-ucode.img "/boot/initramfs-$KERNEL.img" > ucode-initramfs.img
cp /usr/share/edk2-shell/x64/Shell_Full.efi "$NAME_EFI_SHELL-unsigned.efi"

osrel_offset="$(objdump -h /usr/lib/systemd/boot/efi/linuxx64.efi.stub | awk 'NF==7 {size=strtonum("0x"$3); offset=strtonum("0x"$4)} END {print size + offset}')"
kernel_offset="$((osrel_offset + $(stat -Lc%s /etc/os-release)))"
section_alignment="$(LC_ALL=C objdump -p /usr/lib/systemd/boot/efi/linuxx64.efi.stub | awk '/SectionAlignment/ {print strtonum("0x"$2)}')"

initrd_offset_from_default_kernel="$((kernel_offset + $(stat -Lc%s "/boot/vmlinuz-$KERNEL")))"
initrd_offset_from_lts_kernel="$((kernel_offset + $(stat -Lc%s "/boot/vmlinuz-$KERNEL_LTS")))"
offset() {
echo $(("$1" + "$2" + section_alignment - ("$1" + "$2") % section_alignment))
}

cmdline_offset="$((initrd_offset_from_default_kernel + $(stat -Lc%s ucode-initramfs.img)))"
osrel_offset="$(offset 0 "$(LC_ALL=C objdump -h /usr/lib/systemd/boot/efi/linuxx64.efi.stub | awk 'NF==7 {size=strtonum("0x"$3); offset=strtonum("0x"$4)} END {print size + offset}')")"
cmdline_offset="$(offset "$osrel_offset" "$(stat -Lc%s /etc/os-release)")"
initrd_offset_from_cmdline="$(offset "$cmdline_offset" "$(stat -Lc%s cmdline)")"
initrd_offset_from_osrel="$(offset "$osrel_offset" "$(stat -Lc%s /etc/os-release)")"
default_kernel_offset="$(offset "$initrd_offset_from_cmdline" "$(stat -Lc%s ucode-initramfs.img)")"
fallback_kernel_offset="$(offset "$initrd_offset_from_osrel" "$(stat -Lc%s "/boot/initramfs-$KERNEL-fallback.img")")"
fallback_lts_kernel_offset="$(offset "$initrd_offset_from_osrel" "$(stat -Lc%s "/boot/initramfs-$KERNEL_LTS-fallback.img")")"

objcopy \
--add-section .osrel=/etc/os-release --change-section-vma .osrel="$(printf 0x%x "$osrel_offset")" \
--add-section .linux="/boot/vmlinuz-$KERNEL" --change-section-vma .linux="$(printf 0x%x "$kernel_offset")" \
--add-section .initrd=ucode-initramfs.img --change-section-vma .initrd="$(printf 0x%x "$initrd_offset_from_default_kernel")" \
--add-section .cmdline=cmdline --change-section-vma .cmdline="$(printf 0x%x "$cmdline_offset")" \
--add-section .initrd=ucode-initramfs.img --change-section-vma .initrd="$(printf 0x%x "$initrd_offset_from_cmdline")" \
--add-section .linux="/boot/vmlinuz-$KERNEL" --change-section-vma .linux="$(printf 0x%x "$default_kernel_offset")" \
/usr/lib/systemd/boot/efi/linuxx64.efi.stub "$NAME-unsigned.efi"

objcopy \
--add-section .osrel=/etc/os-release --change-section-vma .osrel="$(printf 0x%x "$osrel_offset")" \
--add-section .linux="/boot/vmlinuz-$KERNEL" --change-section-vma .linux="$(printf 0x%x "$kernel_offset")" \
--add-section .initrd="/boot/initramfs-$KERNEL-fallback.img" --change-section-vma .initrd="$(printf 0x%x "$initrd_offset_from_default_kernel")" \
--add-section .initrd="/boot/initramfs-$KERNEL-fallback.img" --change-section-vma .initrd="$(printf 0x%x "$initrd_offset_from_osrel")" \
--add-section .linux="/boot/vmlinuz-$KERNEL" --change-section-vma .linux="$(printf 0x%x "$fallback_kernel_offset")" \
/usr/lib/systemd/boot/efi/linuxx64.efi.stub "$NAME-recovery-unsigned.efi"

objcopy \
--add-section .osrel=/etc/os-release --change-section-vma .osrel="$(printf 0x%x "$osrel_offset")" \
--add-section .linux="/boot/vmlinuz-$KERNEL_LTS" --change-section-vma .linux="$(printf 0x%x "$kernel_offset")" \
--add-section .initrd="/boot/initramfs-$KERNEL_LTS-fallback.img" --change-section-vma .initrd="$(printf 0x%x "$initrd_offset_from_lts_kernel")" \
--add-section .initrd="/boot/initramfs-$KERNEL_LTS-fallback.img" --change-section-vma .initrd="$(printf 0x%x "$initrd_offset_from_osrel")" \
--add-section .linux="/boot/vmlinuz-$KERNEL_LTS" --change-section-vma .linux="$(printf 0x%x "$fallback_lts_kernel_offset")" \
/usr/lib/systemd/boot/efi/linuxx64.efi.stub "$NAME_LTS-recovery-unsigned.efi"

for image in "$NAME" "$NAME-recovery" "$NAME_LTS-recovery" "$NAME_EFI_SHELL"; do
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