def GenBareBonesA64():
sec_null = elfhelper.Section.MakeSectionNull()
sec_text = elfhelper.Section.MakeSectionText(1)
sec_text.data = bytes(ALL_A64)
sec_text.sh_size = len(sec_text.data)
sec_shstrtab = elfhelper.Section.MakeSectionStrTab(".shstrtab")
sec_shstrtab.data = elfhelper.MakeSecStrTabContents(
[sec_null, sec_text, sec_shstrtab])
sec_shstrtab.sh_size = len(sec_shstrtab.data)
seg_exe = elfhelper.Segment.MakeExeSegment(65536)
seg_exe.sections.append(sec_null)
seg_exe.sections.append(sec_text)
seg_pseudo = elfhelper.Segment.MakePseudoSegment()
seg_pseudo.sections.append(sec_shstrtab)
exe = elfhelper.Executable.MakeExecutableA64(
0x400000, [sec_null, sec_text, sec_shstrtab],
[seg_exe, seg_pseudo])
exe.update_vaddrs_and_offset()
print(f"PATCH ENTRY: {sec_text.sh_addr:x}")
exe.ehdr.e_entry = sec_text.sh_addr
print(f"PATCH INSTRUCTIONS: {sec_text.sh_addr:x}")
# simplifying assumption - we stay on the same page so adrp
# does not need patching only the add instruction following it
msg_adr = sec_text.sh_addr + 9 * 4
add_ins = 0x91035021 & 0xff0003ff | ((msg_adr & 0xfff) << 10)
sec_text.data = (ALL_A64[:8] +
add_ins.to_bytes(4, "little") +
ALL_A64[12:])
return exe
def GenBareBonesA32():
sec_null = elfhelper.Section.MakeSectionNull()
sec_text = elfhelper.Section.MakeSectionText(1)
sec_text.data = bytes(ALL_A32)
sec_text.sh_size = len(sec_text.data)
sec_shstrtab = elfhelper.Section.MakeSectionStrTab(".shstrtab")
sec_shstrtab.data = elfhelper.MakeSecStrTabContents([sec_null, sec_text, sec_shstrtab])
sec_shstrtab.sh_size = len(sec_shstrtab.data)
seg_exe = elfhelper.Segment.MakeExeSegment(65536)
seg_exe.sections.append(sec_null)
seg_exe.sections.append(sec_text)
seg_pseudo = elfhelper.Segment.MakePseudoSegment()
seg_pseudo.sections.append(sec_shstrtab)
exe = elfhelper.Executable.MakeExecutableA32(
0x20000, [sec_null, sec_text, sec_shstrtab],
[seg_exe, seg_pseudo])
exe.update_vaddrs_and_offset()
print(f"PATCH ENTRY: {sec_text.sh_addr:x}")
exe.ehdr.e_entry = sec_text.sh_addr
return exe
def GenBareBonesX64() -> elfhelper.Executable:
sec_null = elfhelper.Section.MakeSectionNull()
sec_rodata = elfhelper.Section.MakeSectionRodata(1)
sec_rodata.data = RODATA_X64
sec_rodata.sh_size = len(sec_rodata.data)
sec_text = elfhelper.Section.MakeSectionText(1)
sec_text.data = bytes(TEXT_X64)
sec_text.sh_size = len(sec_text.data)
sec_shstrtab = elfhelper.Section.MakeSectionStrTab(".shstrtab")
sec_shstrtab.data = elfhelper.MakeSecStrTabContents(
[sec_null, sec_rodata, sec_text, sec_shstrtab])
sec_shstrtab.sh_size = len(sec_shstrtab.data)
seg_ro = elfhelper.Segment.MakeROSegment(4096)
seg_exe = elfhelper.Segment.MakeExeSegment(4096)
seg_pseudo = elfhelper.Segment.MakePseudoSegment()
seg_ro.sections.append(sec_null)
seg_ro.sections.append(sec_rodata)
seg_exe.sections.append(sec_text)
seg_pseudo.sections.append(sec_shstrtab)
exe = elfhelper.Executable.MakeExecutableX64(
0x400000,
[sec_null, sec_rodata, sec_text, sec_shstrtab],
[seg_ro, seg_exe, seg_pseudo])
exe.update_vaddrs_and_offset()
print(f"PATCH ENTRY: {sec_text.sh_addr:x}")
exe.ehdr.e_entry = sec_text.sh_addr
print(f"PATCH MSG: {sec_rodata.sh_addr:x}")
# string address is at offset 14
sec_text.data = (bytes(TEXT_X64[:17]) +
sec_rodata.sh_addr.to_bytes(4, "little") +
bytes(TEXT_X64[21:]))
return exe
def Assemble(unit: elf_unit.Unit, create_sym_tab: bool) -> elf.Executable:
sections = []
segments = []
seg_exe = elf.Segment.MakeExeSegment(65536)
segments.append(seg_exe)
sec_null = elf.Section.MakeSectionNull()
sections.append(sec_null)
seg_exe.sections.append(sec_null)
#
sec_text = unit.sec_text
assert len(sec_text.data) > 0
sections.append(sec_text)
seg_exe.sections.append(sec_text)
sec_rodata = unit.sec_rodata
if len(sec_rodata.data) > 0:
seg_ro = elf.Segment.MakeROSegment(65536)
segments.append(seg_ro)
#
sections.append(sec_rodata)
seg_ro.sections.append(sec_rodata)
if len(unit.sec_data.data) + len(unit.sec_bss.data) > 0:
seg_rw = elf.Segment.MakeRWSegment(65536)
segments.append(seg_rw)
sec_data = unit.sec_data
if len(sec_data.data) > 0:
sections.append(sec_data)
seg_rw.sections.append(sec_data)
sec_bss = unit.sec_bss
if len(sec_bss.data) > 0:
sections.append(sec_bss)
seg_rw.sections.append(sec_bss)
seg_pseudo = elf.Segment.MakePseudoSegment()
segments.append(seg_pseudo)
#
if create_sym_tab:
# we do not create the content here since we cannot really do this until
# the section addresses are finalized
which = elf_enum.EI_CLASS.X_64
sec_symtab = elf.Section.MakeSectionSymTab(".symtab", which,
len(sections) + 1)
sections.append(sec_symtab)
sec_symtab.SetData(
bytearray(len(unit.symbols) * elf.Symbol.SIZE[which]))
seg_pseudo.sections.append(sec_symtab)
# TODO: this is not quite right
sec_symtab.sh_info = len(unit.symbols)
sym_names = bytearray()
sym_names += b"\0"
for sym in unit.symbols:
if sym.name:
sym.st_name = len(sym_names)
sym_names += (bytes(sym.name, "utf-8") + b"\0")
else:
sym.st_name = 0
sec_symstrtab = elf.Section.MakeSectionStrTab(".strtab")
sections.append(sec_symstrtab)
sec_symstrtab.SetData(sym_names)
seg_pseudo.sections.append(sec_symstrtab)
sec_shstrtab = elf.Section.MakeSectionStrTab(".shstrtab")
sections.append(sec_shstrtab)
sec_shstrtab.SetData(elf.MakeSecStrTabContents(sections))
seg_pseudo.sections.append(sec_shstrtab)
exe = elf.Executable.MakeExecutableA64(0x400000, sections, segments)
exe.update_vaddrs_and_offset()
if False:
for sym in unit.symbols:
print("@@@SYMS", sym)
for rel in unit.relocations:
print("@@@REL", rel)
for sym in unit.symbols:
if sym.section:
assert sym.section.sh_addr > 0
assert sym.st_value != elf.TO_BE_FILLED_IN_LATER
sym.st_value += sym.section.sh_addr
sym.st_shndx = sym.section.index
for rel in unit.relocations:
_ApplyRelocation(rel)
if create_sym_tab:
# we only put dummiess in the symtable above - do it for real now
sec_symtab.data = bytearray()
for sym in unit.symbols:
sec_symtab.AddData(sym.pack(which))
sym_entry = unit.global_symbol_map["_start"]
assert sym_entry and not sym_entry.is_undefined()
entry_addr = sym_entry.st_value
print(f"PATCH ENTRY: {entry_addr:x}")
exe.ehdr.e_entry = entry_addr
return exe