mirror of https://github.com/zeldaret/botw.git
143 lines
4.6 KiB
Python
143 lines
4.6 KiB
Python
#!/usr/bin/env python3
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from typing import Any, Dict, Set
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import capstone as cs
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from elftools.elf.elffile import ELFFile
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import diff_settings
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from util import utils
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_config: Dict[str, Any] = {}
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diff_settings.apply(_config, {})
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_root = utils.get_repo_root()
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base_elf = ELFFile((_root / _config["baseimg"]).open("rb"))
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my_elf = ELFFile((_root / _config["myimg"]).open("rb"))
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my_symtab = my_elf.get_section_by_name(".symtab")
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if not my_symtab:
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utils.fail(f'{_config["myimg"]} has no symbol table')
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md = cs.Cs(cs.CS_ARCH_ARM64, cs.CS_MODE_ARM)
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md.detail = True
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def get_file_offset(elf, addr: int) -> int:
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for seg in elf.iter_segments():
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if seg.header["p_type"] != "PT_LOAD":
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continue
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if seg["p_vaddr"] <= addr < seg["p_vaddr"] + seg["p_filesz"]:
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return addr - seg["p_vaddr"] + seg["p_offset"]
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assert False
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def get_symbol_file_offset_and_size(elf, table, name: str) -> (int, int):
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syms = table.get_symbol_by_name(name)
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if not syms or len(syms) != 1:
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raise KeyError(name)
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return get_file_offset(elf, syms[0]["st_value"]), syms[0]["st_size"]
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def build_symbol_table(symtab) -> Dict[int, str]:
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table = dict()
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for sym in symtab.iter_symbols():
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addr = sym["st_value"]
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existing_value = table.get(addr, None)
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if existing_value is None or not existing_value.startswith("_Z"):
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table[addr] = sym.name
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return table
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def get_fn_from_base_elf(addr: int, size: int) -> bytes:
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offset = get_file_offset(base_elf, addr)
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base_elf.stream.seek(offset)
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return base_elf.stream.read(size)
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def get_fn_from_my_elf(name: str) -> bytes:
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offset, size = get_symbol_file_offset_and_size(my_elf, my_symtab, name)
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my_elf.stream.seek(offset)
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return my_elf.stream.read(size)
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def check_function_ex(addr: int, size: int, base_fn: bytes, my_fn: bytes) -> bool:
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adrp_pair_registers: Set[int] = set()
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for i1, i2 in zip(md.disasm(base_fn, addr), md.disasm(my_fn, addr)):
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if i1.bytes == i2.bytes:
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if i1.mnemonic == 'adrp':
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adrp_pair_registers.add(i1.operands[0].reg)
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elif i1.mnemonic == 'ldr':
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reg = i1.operands[1].value.mem.base
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if reg in adrp_pair_registers:
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adrp_pair_registers.remove(reg)
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elif i1.mnemonic == 'ldp':
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reg = i1.operands[2].value.mem.base
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if reg in adrp_pair_registers:
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adrp_pair_registers.remove(reg)
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elif i1.mnemonic == 'add':
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reg = i1.operands[1].reg
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if reg in adrp_pair_registers:
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adrp_pair_registers.remove(reg)
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continue
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if i1.mnemonic != i2.mnemonic:
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return False
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# Ignore some address differences until a fully matching executable can be generated.
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if i1.mnemonic == 'bl':
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continue
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if i1.mnemonic == 'b':
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# Needed for tail calls.
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branch_target = int(i1.op_str[1:], 16)
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if not (addr <= branch_target < addr + size):
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continue
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if i1.mnemonic == 'adrp':
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if i1.operands[0].reg != i2.operands[0].reg:
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return False
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adrp_pair_registers.add(i1.operands[0].reg)
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continue
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if i1.mnemonic == 'ldr' or i1.mnemonic == 'str':
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if i1.operands[0].reg != i2.operands[0].reg:
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return False
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if i1.operands[1].value.mem.base != i2.operands[1].value.mem.base:
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return False
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reg = i1.operands[1].value.mem.base
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if reg not in adrp_pair_registers:
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return False
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adrp_pair_registers.remove(reg)
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continue
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if i1.mnemonic == 'ldp' or i1.mnemonic == 'stp':
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if i1.operands[0].reg != i2.operands[0].reg:
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return False
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if i1.operands[1].reg != i2.operands[1].reg:
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return False
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if i1.operands[2].value.mem.base != i2.operands[2].value.mem.base:
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return False
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reg = i1.operands[2].value.mem.base
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if reg not in adrp_pair_registers:
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return False
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adrp_pair_registers.remove(reg)
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continue
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if i1.mnemonic == 'add':
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if i1.operands[0].reg != i2.operands[0].reg:
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return False
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if i1.operands[1].reg != i2.operands[1].reg:
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return False
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reg = i1.operands[1].reg
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if reg not in adrp_pair_registers:
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return False
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adrp_pair_registers.remove(reg)
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continue
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return False
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return True
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