elf2efi: Fix header size calculation

The PE header size calculation failed to take the PE magic and coff
header size into account, which will lead to header truncation if we are
writing only 5 sections.

diff --git a/tools/elf2efi.py b/tools/elf2efi.py
index e233c8e3abaf6fbd812a8454fbf903f2bf5da7af..2e478940f5c17fff15eb0c2dea79ab243ac733cf 100755 (executable)
--- a/tools/elf2efi.py
+++ b/tools/elf2efi.py
@@ -210,6 +210,7 @@ FILE_ALIGNMENT = 512
 
 # Nobody cares about DOS headers, so put the PE header right after.
 PE_OFFSET = 64
+PE_MAGIC = b"PE\0\0"
 
 
 def align_to(x: int, align: int) -> int:
@@ -304,7 +305,10 @@ def copy_sections(elf: ELFFile, opt: PeOptionalHeader) -> typing.List[PeSection]
 
 
 def apply_elf_relative_relocation(
-    reloc: ElfRelocation, image_base: int, sections: typing.List[PeSection], addend_size: int
+    reloc: ElfRelocation,
+    image_base: int,
+    sections: typing.List[PeSection],
+    addend_size: int,
 ):
     # fmt: off
     [target] = [
@@ -439,7 +443,7 @@ def write_pe(
     file.seek(0x3C, io.SEEK_SET)
     file.write(PE_OFFSET.to_bytes(2, byteorder="little"))
     file.seek(PE_OFFSET, io.SEEK_SET)
-    file.write(b"PE\0\0")
+    file.write(PE_MAGIC)
     file.write(coff)
     file.write(opt)
 
@@ -453,6 +457,8 @@ def write_pe(
         file.write(pe_s)
         offset = align_to(offset + len(pe_s.data), FILE_ALIGNMENT)
 
+    assert file.tell() <= opt.SizeOfHeaders
+
     for pe_s in sections:
         file.seek(pe_s.PointerToRawData, io.SEEK_SET)
         file.write(pe_s.data)
@@ -515,6 +521,8 @@ def elf2efi(args: argparse.Namespace):
 
     opt.SizeOfHeaders = align_to(
         PE_OFFSET
+        + len(PE_MAGIC)
+        + sizeof(PeCoffHeader)
         + coff.SizeOfOptionalHeader
         + sizeof(PeSection) * max(coff.NumberOfSections, args.minimum_sections),
         FILE_ALIGNMENT,