fix(dracut.sh): use dynamically uefi's sections offset

* Uefi section are creating by `objcopy` with hardcoded sections offset. This commit allow to have the correct offset between each part of the efi file, needed to create an UKI. Offsets are simply calculated so no sections overlap, as recommended in https://wiki.archlinux.org/title/Unified_kernel_image#Manually Moreover, efi stub file's header is parsed to apply the correct offsets according the section alignment factor. * Remove EFI_SECTION_VMA_INITRD, no need anymore as initrd section offset dynamically calculated Fixes dracutdevs#2275 Signed-off-by: Valentin Lefebvre <valentin.lefebvre@suse.com>
keentux · Mar 16, 2023 · 17786bd · 17786bd
1 parent e9b4774
commit 17786bd
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Showing 2 changed files with 57 additions and 10 deletions.
diff --git a/dracut-functions.sh b/dracut-functions.sh
@@ -1023,3 +1023,25 @@ get_dev_module() {
     fi
     echo "$dev_drivers"
 }
+
+# Check if file is in PE format
+pe_file_format() {
+    if [[ $# -eq 1 ]]; then
+        local magic
+        magic=$(objdump -p "$1" \
+            | awk '{if ($1 == "Magic"){print strtonum("0x"$2)}}')
+        # 0x10b (PE32), 0x20b (PE32+)
+        [[ -n $magic && ($magic == 0x20b || $magic == 0x10b) ]] && return 0
+    fi
+    return 1
+}
+
+# Get the sectionAlignment data from the PE header
+pe_get_section_align() {
+    local align_hex
+    [[ $# -ne "1" ]] && return 1
+    [[ $(pe_file_format "$1") -eq 1 ]] && return 1
+    align_hex=$(objdump -p "$1" \
+        | awk '{if ($1 == "SectionAlignment"){print $2}}')
+    echo "$((16#$align_hex))"
+}
diff --git a/dracut.sh b/dracut.sh
@@ -1506,7 +1506,6 @@ if [[ ! $print_cmdline ]]; then
             exit 1
         fi
         unset EFI_MACHINE_TYPE_NAME
-        EFI_SECTION_VMA_INITRD=0x3000000
         case "${DRACUT_ARCH:-$(uname -m)}" in
             x86_64)
                 EFI_MACHINE_TYPE_NAME=x64
@@ -1516,8 +1515,6 @@ if [[ ! $print_cmdline ]]; then
                 ;;
             aarch64)
                 EFI_MACHINE_TYPE_NAME=aa64
-                # aarch64 kernels are uncompressed and thus larger, so we need a bigger gap between vma sections
-                EFI_SECTION_VMA_INITRD=0x4000000
                 ;;
             *)
                 dfatal "Architecture '${DRACUT_ARCH:-$(uname -m)}' not supported to create a UEFI executable"
@@ -2467,29 +2464,57 @@ if [[ $uefi == yes ]]; then
         fi
     fi
 
+    offs=$(objdump -h "$uefi_stub" 2> /dev/null | awk 'NF==7 {size=strtonum("0x"$3);\
+                offset=strtonum("0x"$4)} END {print size + offset}')
+    if [[ $offs -eq 0 ]]; then
+        dfatal "Failed to get the size of $uefi_stub to create UEFI image file"
+        exit 1
+    fi
+    align=$(pe_get_section_align "$uefi_stub")
+    if [[ $? -eq 1 ]]; then
+        dfatal "Failed to get the sectionAlignment of the stub PE header to create the UEFI image file"
+        exit 1
+    fi
+    offs=$((offs + "$align" - offs % "$align"))
+    [[ -s $dracutsysrootdir/usr/lib/os-release ]] && uefi_osrelease="$dracutsysrootdir/usr/lib/os-release"
+    [[ -s $dracutsysrootdir/etc/os-release ]] && uefi_osrelease="$dracutsysrootdir/etc/os-release"
+    [[ -s $uefi_osrelease ]] \
+        && uefi_osrelease_offs=${offs} \
+        && offs=$((offs + $(stat -Lc%s "$uefi_osrelease"))) \
+        && offs=$((offs + "$align" - offs % "$align"))
+
     if [[ $kernel_cmdline ]] || [[ $hostonly_cmdline == yes && -e "${uefi_outdir}/cmdline.txt" ]]; then
         echo -ne "\x00" >> "$uefi_outdir/cmdline.txt"
         dinfo "Using UEFI kernel cmdline:"
         dinfo "$(tr -d '\000' < "$uefi_outdir/cmdline.txt")"
         uefi_cmdline="${uefi_outdir}/cmdline.txt"
+        uefi_cmdline_offs=${offs}
+        offs=$((offs + $(stat -Lc%s "$uefi_cmdline")))
+        offs=$((offs + "$align" - offs % "$align"))
     else
         unset uefi_cmdline
     fi
 
-    [[ -s $dracutsysrootdir/usr/lib/os-release ]] && uefi_osrelease="$dracutsysrootdir/usr/lib/os-release"
-    [[ -s $dracutsysrootdir/etc/os-release ]] && uefi_osrelease="$dracutsysrootdir/etc/os-release"
     if [[ -s ${dracutsysrootdir}${uefi_splash_image} ]]; then
         uefi_splash_image="${dracutsysrootdir}${uefi_splash_image}"
+        uefi_splash_offs=${offs}
+        offs=$((offs + $(stat -Lc%s "$uefi_splash_image")))
+        offs=$((offs + "$align" - offs % "$align"))
     else
         unset uefi_splash_image
     fi
 
+    uefi_linux_offs="${offs}"
+    offs=$((offs + $(stat -Lc%s "$kernel_image")))
+    offs=$((offs + "$align" - offs % "$align"))
+    uefi_initrd_offs="${offs}"
+
     if objcopy \
-        ${uefi_osrelease:+--add-section .osrel="$uefi_osrelease" --change-section-vma .osrel=0x20000} \
-        ${uefi_cmdline:+--add-section .cmdline="$uefi_cmdline" --change-section-vma .cmdline=0x30000} \
-        ${uefi_splash_image:+--add-section .splash="$uefi_splash_image" --change-section-vma .splash=0x40000} \
-        --add-section .linux="$kernel_image" --change-section-vma .linux=0x2000000 \
-        --add-section .initrd="${DRACUT_TMPDIR}/initramfs.img" --change-section-vma .initrd="${EFI_SECTION_VMA_INITRD}" \
+        ${uefi_osrelease:+--add-section .osrel="$uefi_osrelease" --change-section-vma .osrel=$(printf 0x%x "$uefi_osrelease_offs")} \
+        ${uefi_cmdline:+--add-section .cmdline="$uefi_cmdline" --change-section-vma .cmdline=$(printf 0x%x "$uefi_cmdline_offs")} \
+        ${uefi_splash_image:+--add-section .splash="$uefi_splash_image" --change-section-vma .splash=$(printf 0x%x "$uefi_splash_offs")} \
+        --add-section .linux="$kernel_image" --change-section-vma .linux="$(printf 0x%x "$uefi_linux_offs")" \
+        --add-section .initrd="${DRACUT_TMPDIR}/initramfs.img" --change-section-vma .initrd="$(printf 0x%x "$uefi_initrd_offs")" \
         "$uefi_stub" "${uefi_outdir}/linux.efi"; then
         if [[ -n ${uefi_secureboot_key} && -n ${uefi_secureboot_cert} ]]; then
             if sbsign \