import ctypes import windows import windows.hooks as hooks from windows.generated_def.winstructs import * # This must go to windefs IMAGE_DIRECTORY_ENTRY_EXPORT = 0 IMAGE_DIRECTORY_ENTRY_IMPORT = 1 IMAGE_ORDINAL_FLAG32 = 0x80000000 IMAGE_ORDINAL_FLAG64 = 0x8000000000000000 def RedefineCtypesStruct(struct, replacement): class NewStruct(ctypes.Structure): _fields_ = transform_ctypes_fields(struct, replacement_) NewStruct.__name__ = struct.__name__ return NewStruct # type replacement based on name def transform_ctypes_fields(struct, replacement): return [(name, replacement.get(name, type)) for name, type in struct._fields_] def PEFile(baseaddr): if windows.current_process.bitness == 32: IMAGE_ORDINAL_FLAG = IMAGE_ORDINAL_FLAG32 else: IMAGE_ORDINAL_FLAG = IMAGE_ORDINAL_FLAG64 class RVA(DWORD): @property def addr(self): return baseaddr + self.value def __repr__(self): return "".format(self.value, hex(self.addr)) class StringRVa(RVA): @property def str(self): return ctypes.c_char_p(self.addr).value.decode() def __repr__(self): return "".format(self.value, self.str) def __int__(self): return self.value class IMPORT_BY_NAME(ctypes.Structure): _fields_ = [ ("Hint", WORD), ("Name", BYTE) ] class THUNK_DATA(ctypes.Union): _fields_ = [ ("Ordinal", PVOID), ("AddressOfData", PVOID) ] class IATEntry(ctypes.Structure): _fields_ = [ ("value", PVOID)] @classmethod def create(cls, addr, ord, name): self = cls.from_address(addr) self.addr = addr self.ord = ord self.name = name self.hook = None self.nonhookvalue = self.value return self def __repr__(self): return '<{0} "{1}" ordinal {2}>'.format(self.__class__.__name__, self.name, self.ord) def set_hook(self, callback, types=None): hook = hooks.IATHook(self, callback, types) self.hook = hook hook.enable() return hook def remove_hook(self): if self.hook is None: return False self.hook.disable() self.hook = None return True class PEFile(object): def __init__(self): self.baseaddr = baseaddr def get_DOS_HEADER(self): return IMAGE_DOS_HEADER.from_address(baseaddr) def get_NT_HEADER(self): return self.get_DOS_HEADER().get_NT_HEADER() def get_OptionalHeader(self): return self.get_NT_HEADER().OptionalHeader def get_DataDirectory(self): return self.get_OptionalHeader().DataDirectory def get_IMPORT_DESCRIPTORS(self): import_datadir = self.get_DataDirectory()[IMAGE_DIRECTORY_ENTRY_IMPORT] if import_datadir.VirtualAddress == 0: return [] import_descriptor_addr = RVA(import_datadir.VirtualAddress).addr current_import_descriptor = self.IMAGE_IMPORT_DESCRIPTOR.from_address(import_descriptor_addr) res = [] while current_import_descriptor.FirstThunk: res.append(current_import_descriptor) import_descriptor_addr += ctypes.sizeof(self.IMAGE_IMPORT_DESCRIPTOR) current_import_descriptor = self.IMAGE_IMPORT_DESCRIPTOR.from_address(import_descriptor_addr) return res def get_EXPORT_DIRECTORY(self): export_directory_rva = self.get_DataDirectory()[IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress if export_directory_rva == 0: return None export_directory_addr = baseaddr + export_directory_rva return self._IMAGE_EXPORT_DIRECTORY.from_address(export_directory_addr) @property def exports(self): res = {} raw_exports = self.get_EXPORT_DIRECTORY().get_exports() for id, rva_addr, rva_name in raw_exports: res[id] = rva_addr.addr if rva_name is not None: res[rva_name.str] = rva_addr.addr return res # TODO: get imports by parsing other modules exports if no INT @property def imports(self): res = {} for import_descriptor in self.get_IMPORT_DESCRIPTORS(): INT = import_descriptor.get_INT() IAT = import_descriptor.get_IAT() if INT is not None: for iat_entry, (ord, name) in zip(IAT, INT): iat_entry.name = name.decode() iat_entry.ord = ord res.setdefault(import_descriptor.Name.str.lower(),[]).extend(IAT) return res # Will be usable as `self.IMAGE_IMPORT_DESCRIPTOR` class IMAGE_IMPORT_DESCRIPTOR(ctypes.Structure): _fields_ = transform_ctypes_fields(IMAGE_IMPORT_DESCRIPTOR, {"Name" : StringRVa, "OriginalFirstThunk" : RVA, "FirstThunk" : RVA}) def get_INT(self): if not self.OriginalFirstThunk.value: return None int_addr = self.OriginalFirstThunk.addr int_entry = THUNK_DATA.from_address(int_addr) res = [] while int_entry.Ordinal: if int_entry.Ordinal & IMAGE_ORDINAL_FLAG: res += [(int_entry.Ordinal & 0x7fffffff, None)] else: import_by_name = IMPORT_BY_NAME.from_address(baseaddr + int_entry.AddressOfData) name = ctypes.c_char_p(ctypes.addressof(import_by_name) + IMPORT_BY_NAME.Name.offset).value res.append((import_by_name.Hint, name)) int_addr += ctypes.sizeof(THUNK_DATA) int_entry = THUNK_DATA.from_address(int_addr) return res def get_IAT(self): iat_addr = self.FirstThunk.addr iat_entry = THUNK_DATA.from_address(iat_addr) res = [] while iat_entry.Ordinal: res.append(IATEntry.create(iat_addr, -1, "??")) iat_addr += ctypes.sizeof(THUNK_DATA) iat_entry = THUNK_DATA.from_address(iat_addr) return res # Will be usable as `self._IMAGE_EXPORT_DIRECTORY` class _IMAGE_EXPORT_DIRECTORY(ctypes.Structure): _fields_ = transform_ctypes_fields(IMAGE_EXPORT_DIRECTORY, {"Name" : StringRVa, "AddressOfFunctions" : RVA, "AddressOfNames" : RVA, "AddressOfNameOrdinals": RVA}) def get_exports(self): NameOrdinals = (WORD * self.NumberOfNames).from_address(self.AddressOfNameOrdinals.addr) NameOrdinals = list(NameOrdinals) Functions = (RVA * self.NumberOfFunctions).from_address(self.AddressOfFunctions.addr) Names = (StringRVa * self.NumberOfNames).from_address(self.AddressOfNames.addr) res = [] for nb,func in enumerate(Functions): if nb in NameOrdinals: name = Names[NameOrdinals.index(nb)] else: name = None res.append((nb, func, name)) return res current_pe = PEFile() class IMAGE_DOS_HEADER(ctypes.Structure): _fields_ = [ ("e_magic", CHAR * 2), ("e_cblp", WORD), ("e_cp", WORD), ("e_crlc", WORD), ("e_cparhdr", WORD), ("e_minalloc", WORD), ("e_maxalloc", WORD), ("e_ss", WORD), ("e_sp", WORD), ("e_csum", WORD), ("e_ip", WORD), ("e_cs", WORD), ("e_lfarlc", WORD), ("e_ovno", WORD), ("e_res", WORD * 4), ("e_oemid", WORD), ("e_oeminfo", WORD), ("e_res2", WORD * 10), ("e_lfanew", DWORD), ] def get_NT_HEADER(self): if windows.current_process.bitness == 32: return IMAGE_NT_HEADERS32.from_address(baseaddr + self.e_lfanew) return IMAGE_NT_HEADERS64.from_address(baseaddr + self.e_lfanew) return current_pe tst = PEFile.__code__.co_consts[13]