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>

dracut-functions.sh

@@ -1023,3 +1023,24 @@ get_dev_module() {
     fi
     echo "$dev_drivers"
 }
+
+# Check if file is in PE format
+pe_file_format() {
+    if [[ $# -eq 1 ]]; then
+        dos_header=$(hexdump -s 0 -n 64 -e'64/1 "%_c"' "$1")
+        signature=$(hexdump -s 128 -n 4 -e'4 "%_c"' "$1")
+        [[ ($dos_header =~ "MZ") && ($signature == 'PE\0\0') ]] && return 0
+    fi
+    return 1
+}
+
+# Get the sectionAlignment data fromn the PE header
+pe_get_section_align() {
+    local align_hex
+    [[ $# -ne "1" ]] && return 1
+    [[ $(pe_file_format "$1") -eq 1 ]] && return 1
+    for raw in $(hexdump -s 184 -n 4 -e'4/1 "%02x "' "$1"); do
+        align_hex+="$((16#${raw}))"
+    done
+    echo "$((16#$align_hex))"
+}

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 \