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-rwxr-xr-xtools/elf2efi.py252
1 files changed, 132 insertions, 120 deletions
diff --git a/tools/elf2efi.py b/tools/elf2efi.py
index 54f64fa..cb1a284 100755
--- a/tools/elf2efi.py
+++ b/tools/elf2efi.py
@@ -26,6 +26,7 @@ import hashlib
import io
import os
import pathlib
+import sys
import time
import typing
from ctypes import (
@@ -55,26 +56,26 @@ from elftools.elf.relocation import (
class PeCoffHeader(LittleEndianStructure):
_fields_ = (
- ("Machine", c_uint16),
- ("NumberOfSections", c_uint16),
- ("TimeDateStamp", c_uint32),
+ ("Machine", c_uint16),
+ ("NumberOfSections", c_uint16),
+ ("TimeDateStamp", c_uint32),
("PointerToSymbolTable", c_uint32),
- ("NumberOfSymbols", c_uint32),
+ ("NumberOfSymbols", c_uint32),
("SizeOfOptionalHeader", c_uint16),
- ("Characteristics", c_uint16),
+ ("Characteristics", c_uint16),
)
class PeDataDirectory(LittleEndianStructure):
_fields_ = (
("VirtualAddress", c_uint32),
- ("Size", c_uint32),
+ ("Size", c_uint32),
)
class PeRelocationBlock(LittleEndianStructure):
_fields_ = (
- ("PageRVA", c_uint32),
+ ("PageRVA", c_uint32),
("BlockSize", c_uint32),
)
@@ -86,62 +87,62 @@ class PeRelocationBlock(LittleEndianStructure):
class PeRelocationEntry(LittleEndianStructure):
_fields_ = (
("Offset", c_uint16, 12),
- ("Type", c_uint16, 4),
+ ("Type", c_uint16, 4),
)
class PeOptionalHeaderStart(LittleEndianStructure):
_fields_ = (
- ("Magic", c_uint16),
- ("MajorLinkerVersion", c_uint8),
- ("MinorLinkerVersion", c_uint8),
- ("SizeOfCode", c_uint32),
- ("SizeOfInitializedData", c_uint32),
+ ("Magic", c_uint16),
+ ("MajorLinkerVersion", c_uint8),
+ ("MinorLinkerVersion", c_uint8),
+ ("SizeOfCode", c_uint32),
+ ("SizeOfInitializedData", c_uint32),
("SizeOfUninitializedData", c_uint32),
- ("AddressOfEntryPoint", c_uint32),
- ("BaseOfCode", c_uint32),
+ ("AddressOfEntryPoint", c_uint32),
+ ("BaseOfCode", c_uint32),
)
class PeOptionalHeaderMiddle(LittleEndianStructure):
_fields_ = (
- ("SectionAlignment", c_uint32),
- ("FileAlignment", c_uint32),
+ ("SectionAlignment", c_uint32),
+ ("FileAlignment", c_uint32),
("MajorOperatingSystemVersion", c_uint16),
("MinorOperatingSystemVersion", c_uint16),
- ("MajorImageVersion", c_uint16),
- ("MinorImageVersion", c_uint16),
- ("MajorSubsystemVersion", c_uint16),
- ("MinorSubsystemVersion", c_uint16),
- ("Win32VersionValue", c_uint32),
- ("SizeOfImage", c_uint32),
- ("SizeOfHeaders", c_uint32),
- ("CheckSum", c_uint32),
- ("Subsystem", c_uint16),
- ("DllCharacteristics", c_uint16),
+ ("MajorImageVersion", c_uint16),
+ ("MinorImageVersion", c_uint16),
+ ("MajorSubsystemVersion", c_uint16),
+ ("MinorSubsystemVersion", c_uint16),
+ ("Win32VersionValue", c_uint32),
+ ("SizeOfImage", c_uint32),
+ ("SizeOfHeaders", c_uint32),
+ ("CheckSum", c_uint32),
+ ("Subsystem", c_uint16),
+ ("DllCharacteristics", c_uint16),
)
class PeOptionalHeaderEnd(LittleEndianStructure):
_fields_ = (
- ("LoaderFlags", c_uint32),
- ("NumberOfRvaAndSizes", c_uint32),
- ("ExportTable", PeDataDirectory),
- ("ImportTable", PeDataDirectory),
- ("ResourceTable", PeDataDirectory),
- ("ExceptionTable", PeDataDirectory),
- ("CertificateTable", PeDataDirectory),
- ("BaseRelocationTable", PeDataDirectory),
- ("Debug", PeDataDirectory),
- ("Architecture", PeDataDirectory),
- ("GlobalPtr", PeDataDirectory),
- ("TLSTable", PeDataDirectory),
- ("LoadConfigTable", PeDataDirectory),
- ("BoundImport", PeDataDirectory),
- ("IAT", PeDataDirectory),
+ ("LoaderFlags", c_uint32),
+ ("NumberOfRvaAndSizes", c_uint32),
+ ("ExportTable", PeDataDirectory),
+ ("ImportTable", PeDataDirectory),
+ ("ResourceTable", PeDataDirectory),
+ ("ExceptionTable", PeDataDirectory),
+ ("CertificateTable", PeDataDirectory),
+ ("BaseRelocationTable", PeDataDirectory),
+ ("Debug", PeDataDirectory),
+ ("Architecture", PeDataDirectory),
+ ("GlobalPtr", PeDataDirectory),
+ ("TLSTable", PeDataDirectory),
+ ("LoadConfigTable", PeDataDirectory),
+ ("BoundImport", PeDataDirectory),
+ ("IAT", PeDataDirectory),
("DelayImportDescriptor", PeDataDirectory),
- ("CLRRuntimeHeader", PeDataDirectory),
- ("Reserved", PeDataDirectory),
+ ("CLRRuntimeHeader", PeDataDirectory),
+ ("Reserved", PeDataDirectory),
)
@@ -152,44 +153,44 @@ class PeOptionalHeader(LittleEndianStructure):
class PeOptionalHeader32(PeOptionalHeader):
_anonymous_ = ("Start", "Middle", "End")
_fields_ = (
- ("Start", PeOptionalHeaderStart),
- ("BaseOfData", c_uint32),
- ("ImageBase", c_uint32),
- ("Middle", PeOptionalHeaderMiddle),
+ ("Start", PeOptionalHeaderStart),
+ ("BaseOfData", c_uint32),
+ ("ImageBase", c_uint32),
+ ("Middle", PeOptionalHeaderMiddle),
("SizeOfStackReserve", c_uint32),
- ("SizeOfStackCommit", c_uint32),
- ("SizeOfHeapReserve", c_uint32),
- ("SizeOfHeapCommit", c_uint32),
- ("End", PeOptionalHeaderEnd),
+ ("SizeOfStackCommit", c_uint32),
+ ("SizeOfHeapReserve", c_uint32),
+ ("SizeOfHeapCommit", c_uint32),
+ ("End", PeOptionalHeaderEnd),
)
class PeOptionalHeader32Plus(PeOptionalHeader):
_anonymous_ = ("Start", "Middle", "End")
_fields_ = (
- ("Start", PeOptionalHeaderStart),
- ("ImageBase", c_uint64),
- ("Middle", PeOptionalHeaderMiddle),
+ ("Start", PeOptionalHeaderStart),
+ ("ImageBase", c_uint64),
+ ("Middle", PeOptionalHeaderMiddle),
("SizeOfStackReserve", c_uint64),
- ("SizeOfStackCommit", c_uint64),
- ("SizeOfHeapReserve", c_uint64),
- ("SizeOfHeapCommit", c_uint64),
- ("End", PeOptionalHeaderEnd),
+ ("SizeOfStackCommit", c_uint64),
+ ("SizeOfHeapReserve", c_uint64),
+ ("SizeOfHeapCommit", c_uint64),
+ ("End", PeOptionalHeaderEnd),
)
class PeSection(LittleEndianStructure):
_fields_ = (
- ("Name", c_char * 8),
- ("VirtualSize", c_uint32),
- ("VirtualAddress", c_uint32),
- ("SizeOfRawData", c_uint32),
- ("PointerToRawData", c_uint32),
+ ("Name", c_char * 8),
+ ("VirtualSize", c_uint32),
+ ("VirtualAddress", c_uint32),
+ ("SizeOfRawData", c_uint32),
+ ("PointerToRawData", c_uint32),
("PointerToRelocations", c_uint32),
("PointerToLinenumbers", c_uint32),
- ("NumberOfRelocations", c_uint16),
- ("NumberOfLinenumbers", c_uint16),
- ("Characteristics", c_uint32),
+ ("NumberOfRelocations", c_uint16),
+ ("NumberOfLinenumbers", c_uint16),
+ ("Characteristics", c_uint32),
)
def __init__(self):
@@ -206,12 +207,13 @@ assert sizeof(PeOptionalHeader32Plus) == 240
PE_CHARACTERISTICS_RX = 0x60000020 # CNT_CODE|MEM_READ|MEM_EXECUTE
PE_CHARACTERISTICS_RW = 0xC0000040 # CNT_INITIALIZED_DATA|MEM_READ|MEM_WRITE
-PE_CHARACTERISTICS_R = 0x40000040 # CNT_INITIALIZED_DATA|MEM_READ
+PE_CHARACTERISTICS_R = 0x40000040 # CNT_INITIALIZED_DATA|MEM_READ
IGNORE_SECTIONS = [
".eh_frame",
".eh_frame_hdr",
".ARM.exidx",
+ ".relro_padding",
]
IGNORE_SECTION_TYPES = [
@@ -246,9 +248,12 @@ def align_down(x: int, align: int) -> int:
def next_section_address(sections: typing.List[PeSection]) -> int:
- return align_to(
- sections[-1].VirtualAddress + sections[-1].VirtualSize, SECTION_ALIGNMENT
- )
+ return align_to(sections[-1].VirtualAddress + sections[-1].VirtualSize,
+ SECTION_ALIGNMENT)
+
+
+class BadSectionError(ValueError):
+ "One of the sections is in a bad state"
def iter_copy_sections(elf: ELFFile) -> typing.Iterator[PeSection]:
@@ -261,8 +266,9 @@ def iter_copy_sections(elf: ELFFile) -> typing.Iterator[PeSection]:
relro = None
for elf_seg in elf.iter_segments():
if elf_seg["p_type"] == "PT_LOAD" and elf_seg["p_align"] != SECTION_ALIGNMENT:
- raise RuntimeError("ELF segments are not properly aligned.")
- elif elf_seg["p_type"] == "PT_GNU_RELRO":
+ raise BadSectionError(f"ELF segment {elf_seg['p_type']} is not properly aligned"
+ f" ({elf_seg['p_align']} != {SECTION_ALIGNMENT})")
+ if elf_seg["p_type"] == "PT_GNU_RELRO":
relro = elf_seg
for elf_s in elf.iter_sections():
@@ -270,10 +276,14 @@ def iter_copy_sections(elf: ELFFile) -> typing.Iterator[PeSection]:
elf_s["sh_flags"] & SH_FLAGS.SHF_ALLOC == 0
or elf_s["sh_type"] in IGNORE_SECTION_TYPES
or elf_s.name in IGNORE_SECTIONS
+ or elf_s["sh_size"] == 0
):
continue
if elf_s["sh_type"] not in ["SHT_PROGBITS", "SHT_NOBITS"]:
- raise RuntimeError(f"Unknown section {elf_s.name}.")
+ raise BadSectionError(f"Unknown section {elf_s.name} with type {elf_s['sh_type']}")
+ if elf_s.name == '.got':
+ # FIXME: figure out why those sections are inserted
+ print("WARNING: Non-empty .got section", file=sys.stderr)
if elf_s["sh_flags"] & SH_FLAGS.SHF_EXECINSTR:
rwx = PE_CHARACTERISTICS_RX
@@ -305,7 +315,7 @@ def iter_copy_sections(elf: ELFFile) -> typing.Iterator[PeSection]:
def convert_sections(elf: ELFFile, opt: PeOptionalHeader) -> typing.List[PeSection]:
- last_vma = 0
+ last_vma = (0, 0)
sections = []
for pe_s in iter_copy_sections(elf):
@@ -325,10 +335,11 @@ def convert_sections(elf: ELFFile, opt: PeOptionalHeader) -> typing.List[PeSecti
PE_CHARACTERISTICS_R: b".rodata",
}[pe_s.Characteristics]
- # This can happen if not building with `-z separate-code`.
- if pe_s.VirtualAddress < last_vma:
- raise RuntimeError("Overlapping PE sections.")
- last_vma = pe_s.VirtualAddress + pe_s.VirtualSize
+ # This can happen if not building with '-z separate-code'.
+ if pe_s.VirtualAddress < sum(last_vma):
+ raise BadSectionError(f"Section {pe_s.Name.decode()!r} @0x{pe_s.VirtualAddress:x} overlaps"
+ f" previous section @0x{last_vma[0]:x}+0x{last_vma[1]:x}=@0x{sum(last_vma):x}")
+ last_vma = (pe_s.VirtualAddress, pe_s.VirtualSize)
if pe_s.Name == b".text":
opt.BaseOfCode = pe_s.VirtualAddress
@@ -355,9 +366,9 @@ def copy_sections(
if not elf_s:
continue
if elf_s.data_alignment > 1 and SECTION_ALIGNMENT % elf_s.data_alignment != 0:
- raise RuntimeError(f"ELF section {name} is not aligned.")
+ raise BadSectionError(f"ELF section {name} is not aligned")
if elf_s["sh_flags"] & (SH_FLAGS.SHF_EXECINSTR | SH_FLAGS.SHF_WRITE) != 0:
- raise RuntimeError(f"ELF section {name} is not read-only data.")
+ raise BadSectionError(f"ELF section {name} is not read-only data")
pe_s = PeSection()
pe_s.Name = name.encode()
@@ -376,12 +387,8 @@ def apply_elf_relative_relocation(
sections: typing.List[PeSection],
addend_size: int,
):
- # fmt: off
- [target] = [
- pe_s for pe_s in sections
- if pe_s.VirtualAddress <= reloc["r_offset"] < pe_s.VirtualAddress + len(pe_s.data)
- ]
- # fmt: on
+ [target] = [pe_s for pe_s in sections
+ if pe_s.VirtualAddress <= reloc["r_offset"] < pe_s.VirtualAddress + len(pe_s.data)]
addend_offset = reloc["r_offset"] - target.VirtualAddress
@@ -425,9 +432,10 @@ def convert_elf_reloc_table(
continue
if reloc["r_info_type"] == RELATIVE_RELOC:
- apply_elf_relative_relocation(
- reloc, elf_image_base, sections, elf.elfclass // 8
- )
+ apply_elf_relative_relocation(reloc,
+ elf_image_base,
+ sections,
+ elf.elfclass // 8)
# Now that the ELF relocation has been applied, we can create a PE relocation.
block_rva = reloc["r_offset"] & ~0xFFF
@@ -442,7 +450,7 @@ def convert_elf_reloc_table(
continue
- raise RuntimeError(f"Unsupported relocation {reloc}")
+ raise BadSectionError(f"Unsupported relocation {reloc}")
def convert_elf_relocations(
@@ -453,27 +461,25 @@ def convert_elf_relocations(
) -> typing.Optional[PeSection]:
dynamic = elf.get_section_by_name(".dynamic")
if dynamic is None:
- raise RuntimeError("ELF .dynamic section is missing.")
+ raise BadSectionError("ELF .dynamic section is missing")
[flags_tag] = dynamic.iter_tags("DT_FLAGS_1")
if not flags_tag["d_val"] & ENUM_DT_FLAGS_1["DF_1_PIE"]:
- raise RuntimeError("ELF file is not a PIE.")
+ raise ValueError("ELF file is not a PIE")
# This checks that the ELF image base is 0.
symtab = elf.get_section_by_name(".symtab")
if symtab:
exe_start = symtab.get_symbol_by_name("__executable_start")
if exe_start and exe_start[0]["st_value"] != 0:
- raise RuntimeError("Unexpected ELF image base.")
-
- opt.SizeOfHeaders = align_to(
- PE_OFFSET
- + len(PE_MAGIC)
- + sizeof(PeCoffHeader)
- + sizeof(opt)
- + sizeof(PeSection) * max(len(sections) + 1, minimum_sections),
- FILE_ALIGNMENT,
- )
+ raise ValueError("Unexpected ELF image base")
+
+ opt.SizeOfHeaders = align_to(PE_OFFSET
+ + len(PE_MAGIC)
+ + sizeof(PeCoffHeader)
+ + sizeof(opt)
+ + sizeof(PeSection) * max(len(sections) + 1, minimum_sections),
+ FILE_ALIGNMENT)
# We use the basic VMA layout from the ELF image in the PE image. This could cause the first
# section to overlap the PE image headers during runtime at VMA 0. We can simply apply a fixed
@@ -482,9 +488,8 @@ def convert_elf_relocations(
# the ELF portions of the image.
segment_offset = 0
if sections[0].VirtualAddress < opt.SizeOfHeaders:
- segment_offset = align_to(
- opt.SizeOfHeaders - sections[0].VirtualAddress, SECTION_ALIGNMENT
- )
+ segment_offset = align_to(opt.SizeOfHeaders - sections[0].VirtualAddress,
+ SECTION_ALIGNMENT)
opt.AddressOfEntryPoint = elf["e_entry"] + segment_offset
opt.BaseOfCode += segment_offset
@@ -494,10 +499,12 @@ def convert_elf_relocations(
pe_reloc_blocks: typing.Dict[int, PeRelocationBlock] = {}
for reloc_type, reloc_table in dynamic.get_relocation_tables().items():
if reloc_type not in ["REL", "RELA"]:
- raise RuntimeError("Unsupported relocation type {elf_reloc_type}.")
- convert_elf_reloc_table(
- elf, reloc_table, opt.ImageBase + segment_offset, sections, pe_reloc_blocks
- )
+ raise BadSectionError(f"Unsupported relocation type {reloc_type}")
+ convert_elf_reloc_table(elf,
+ reloc_table,
+ opt.ImageBase + segment_offset,
+ sections,
+ pe_reloc_blocks)
for pe_s in sections:
pe_s.VirtualAddress += segment_offset
@@ -517,9 +524,7 @@ def convert_elf_relocations(
block.entries.append(PeRelocationEntry())
block.PageRVA += segment_offset
- block.BlockSize = (
- sizeof(PeRelocationBlock) + sizeof(PeRelocationEntry) * n_relocs
- )
+ block.BlockSize = sizeof(PeRelocationBlock) + sizeof(PeRelocationEntry) * n_relocs
data += block
for entry in sorted(block.entries, key=lambda e: e.Offset):
data += entry
@@ -539,7 +544,10 @@ def convert_elf_relocations(
def write_pe(
- file, coff: PeCoffHeader, opt: PeOptionalHeader, sections: typing.List[PeSection]
+ file,
+ coff: PeCoffHeader,
+ opt: PeOptionalHeader,
+ sections: typing.List[PeSection],
):
file.write(b"MZ")
file.seek(0x3C, io.SEEK_SET)
@@ -552,8 +560,8 @@ def write_pe(
offset = opt.SizeOfHeaders
for pe_s in sorted(sections, key=lambda s: s.VirtualAddress):
if pe_s.VirtualAddress < opt.SizeOfHeaders:
- # Linker script should make sure this does not happen.
- raise RuntimeError(f"Section {pe_s.Name} overlapping PE headers.")
+ raise BadSectionError(f"Section {pe_s.Name} @0x{pe_s.VirtualAddress:x} overlaps"
+ " PE headers ending at 0x{opt.SizeOfHeaders:x}")
pe_s.PointerToRawData = offset
file.write(pe_s)
@@ -571,9 +579,9 @@ def write_pe(
def elf2efi(args: argparse.Namespace):
elf = ELFFile(args.ELF)
if not elf.little_endian:
- raise RuntimeError("ELF file is not little-endian.")
+ raise ValueError("ELF file is not little-endian")
if elf["e_type"] not in ["ET_DYN", "ET_EXEC"]:
- raise RuntimeError("Unsupported ELF type.")
+ raise ValueError(f"Unsupported ELF type {elf['e_type']}")
pe_arch = {
"EM_386": 0x014C,
@@ -584,7 +592,7 @@ def elf2efi(args: argparse.Namespace):
"EM_X86_64": 0x8664,
}.get(elf["e_machine"])
if pe_arch is None:
- raise RuntimeError(f"Unsupported ELF arch {elf['e_machine']}")
+ raise ValueError(f"Unsupported ELF architecture {elf['e_machine']}")
coff = PeCoffHeader()
opt = PeOptionalHeader32() if elf.elfclass == 32 else PeOptionalHeader32Plus()
@@ -637,7 +645,7 @@ def elf2efi(args: argparse.Namespace):
write_pe(args.PE, coff, opt, sections)
-def main():
+def create_parser() -> argparse.ArgumentParser:
parser = argparse.ArgumentParser(description="Convert ELF binaries to PE/EFI")
parser.add_argument(
"--version-major",
@@ -691,7 +699,11 @@ def main():
default="",
help="Copy these sections if found",
)
+ return parser
+
+def main():
+ parser = create_parser()
elf2efi(parser.parse_args())
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-28 08:56:01 +0000