Microsoft Compound File Binary (CFB), AKA OLE (Object Linking and Embedding) file format: Python parsing library

This page hosts a formal specification of Microsoft Compound File Binary (CFB), AKA OLE (Object Linking and Embedding) file format using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.

Usage

Runtime library

All parsing code for Python generated by Kaitai Struct depends on the Python runtime library. You have to install it before you can parse data.

The Python runtime library can be installed from PyPI:

python3 -m pip install kaitaistruct

Code

Parse a local file and get structure in memory:

data = MicrosoftCfb.from_file("path/to/local/file.bin")

Or parse structure from a bytes:

from kaitaistruct import KaitaiStream, BytesIO

raw = b"\x00\x01\x02..."
data = MicrosoftCfb(KaitaiStream(BytesIO(raw)))

After that, one can get various attributes from the structure by invoking getter methods like:

data.header # => get header

Python source code to parse Microsoft Compound File Binary (CFB), AKA OLE (Object Linking and Embedding) file format

microsoft_cfb.py

# This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild
# type: ignore

import kaitaistruct
from kaitaistruct import KaitaiStruct, KaitaiStream, BytesIO
from enum import IntEnum


if getattr(kaitaistruct, 'API_VERSION', (0, 9)) < (0, 11):
    raise Exception("Incompatible Kaitai Struct Python API: 0.11 or later is required, but you have %s" % (kaitaistruct.__version__))

class MicrosoftCfb(KaitaiStruct):
    def __init__(self, _io, _parent=None, _root=None):
        super(MicrosoftCfb, self).__init__(_io)
        self._parent = _parent
        self._root = _root or self
        self._read()

    def _read(self):
        self.header = MicrosoftCfb.CfbHeader(self._io, self, self._root)


    def _fetch_instances(self):
        pass
        self.header._fetch_instances()
        _ = self.dir
        if hasattr(self, '_m_dir'):
            pass
            self._m_dir._fetch_instances()

        _ = self.fat
        if hasattr(self, '_m_fat'):
            pass
            self._m_fat._fetch_instances()


    class CfbHeader(KaitaiStruct):
        def __init__(self, _io, _parent=None, _root=None):
            super(MicrosoftCfb.CfbHeader, self).__init__(_io)
            self._parent = _parent
            self._root = _root
            self._read()

        def _read(self):
            self.signature = self._io.read_bytes(8)
            if not self.signature == b"\xD0\xCF\x11\xE0\xA1\xB1\x1A\xE1":
                raise kaitaistruct.ValidationNotEqualError(b"\xD0\xCF\x11\xE0\xA1\xB1\x1A\xE1", self.signature, self._io, u"/types/cfb_header/seq/0")
            self.clsid = self._io.read_bytes(16)
            if not self.clsid == b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00":
                raise kaitaistruct.ValidationNotEqualError(b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", self.clsid, self._io, u"/types/cfb_header/seq/1")
            self.version_minor = self._io.read_u2le()
            self.version_major = self._io.read_u2le()
            self.byte_order = self._io.read_bytes(2)
            if not self.byte_order == b"\xFE\xFF":
                raise kaitaistruct.ValidationNotEqualError(b"\xFE\xFF", self.byte_order, self._io, u"/types/cfb_header/seq/4")
            self.sector_shift = self._io.read_u2le()
            self.mini_sector_shift = self._io.read_u2le()
            self.reserved1 = self._io.read_bytes(6)
            self.size_dir = self._io.read_s4le()
            self.size_fat = self._io.read_s4le()
            self.ofs_dir = self._io.read_s4le()
            self.transaction_seq = self._io.read_s4le()
            self.mini_stream_cutoff_size = self._io.read_s4le()
            self.ofs_mini_fat = self._io.read_s4le()
            self.size_mini_fat = self._io.read_s4le()
            self.ofs_difat = self._io.read_s4le()
            self.size_difat = self._io.read_s4le()
            self.difat = []
            for i in range(109):
                self.difat.append(self._io.read_s4le())



        def _fetch_instances(self):
            pass
            for i in range(len(self.difat)):
                pass



    class DirEntry(KaitaiStruct):

        class ObjType(IntEnum):
            unknown = 0
            storage = 1
            stream = 2
            root_storage = 5

        class RbColor(IntEnum):
            red = 0
            black = 1
        def __init__(self, _io, _parent=None, _root=None):
            super(MicrosoftCfb.DirEntry, self).__init__(_io)
            self._parent = _parent
            self._root = _root
            self._read()

        def _read(self):
            self.name = (self._io.read_bytes(64)).decode(u"UTF-16LE")
            self.name_len = self._io.read_u2le()
            self.object_type = KaitaiStream.resolve_enum(MicrosoftCfb.DirEntry.ObjType, self._io.read_u1())
            self.color_flag = KaitaiStream.resolve_enum(MicrosoftCfb.DirEntry.RbColor, self._io.read_u1())
            self.left_sibling_id = self._io.read_s4le()
            self.right_sibling_id = self._io.read_s4le()
            self.child_id = self._io.read_s4le()
            self.clsid = self._io.read_bytes(16)
            self.state = self._io.read_u4le()
            self.time_create = self._io.read_u8le()
            self.time_mod = self._io.read_u8le()
            self.ofs = self._io.read_s4le()
            self.size = self._io.read_u8le()


        def _fetch_instances(self):
            pass
            _ = self.child
            if hasattr(self, '_m_child'):
                pass
                self._m_child._fetch_instances()

            _ = self.left_sibling
            if hasattr(self, '_m_left_sibling'):
                pass
                self._m_left_sibling._fetch_instances()

            _ = self.mini_stream
            if hasattr(self, '_m_mini_stream'):
                pass

            _ = self.right_sibling
            if hasattr(self, '_m_right_sibling'):
                pass
                self._m_right_sibling._fetch_instances()


        @property
        def child(self):
            if hasattr(self, '_m_child'):
                return self._m_child

            if self.child_id != -1:
                pass
                io = self._root._io
                _pos = io.pos()
                io.seek((self._root.header.ofs_dir + 1) * self._root.sector_size + self.child_id * 128)
                self._m_child = MicrosoftCfb.DirEntry(io, self, self._root)
                io.seek(_pos)

            return getattr(self, '_m_child', None)

        @property
        def left_sibling(self):
            if hasattr(self, '_m_left_sibling'):
                return self._m_left_sibling

            if self.left_sibling_id != -1:
                pass
                io = self._root._io
                _pos = io.pos()
                io.seek((self._root.header.ofs_dir + 1) * self._root.sector_size + self.left_sibling_id * 128)
                self._m_left_sibling = MicrosoftCfb.DirEntry(io, self, self._root)
                io.seek(_pos)

            return getattr(self, '_m_left_sibling', None)

        @property
        def mini_stream(self):
            if hasattr(self, '_m_mini_stream'):
                return self._m_mini_stream

            if self.object_type == MicrosoftCfb.DirEntry.ObjType.root_storage:
                pass
                io = self._root._io
                _pos = io.pos()
                io.seek((self.ofs + 1) * self._root.sector_size)
                self._m_mini_stream = io.read_bytes(self.size)
                io.seek(_pos)

            return getattr(self, '_m_mini_stream', None)

        @property
        def right_sibling(self):
            if hasattr(self, '_m_right_sibling'):
                return self._m_right_sibling

            if self.right_sibling_id != -1:
                pass
                io = self._root._io
                _pos = io.pos()
                io.seek((self._root.header.ofs_dir + 1) * self._root.sector_size + self.right_sibling_id * 128)
                self._m_right_sibling = MicrosoftCfb.DirEntry(io, self, self._root)
                io.seek(_pos)

            return getattr(self, '_m_right_sibling', None)


    class FatEntries(KaitaiStruct):
        def __init__(self, _io, _parent=None, _root=None):
            super(MicrosoftCfb.FatEntries, self).__init__(_io)
            self._parent = _parent
            self._root = _root
            self._read()

        def _read(self):
            self.entries = []
            i = 0
            while not self._io.is_eof():
                self.entries.append(self._io.read_s4le())
                i += 1



        def _fetch_instances(self):
            pass
            for i in range(len(self.entries)):
                pass



    @property
    def dir(self):
        if hasattr(self, '_m_dir'):
            return self._m_dir

        _pos = self._io.pos()
        self._io.seek((self.header.ofs_dir + 1) * self.sector_size)
        self._m_dir = MicrosoftCfb.DirEntry(self._io, self, self._root)
        self._io.seek(_pos)
        return getattr(self, '_m_dir', None)

    @property
    def fat(self):
        if hasattr(self, '_m_fat'):
            return self._m_fat

        _pos = self._io.pos()
        self._io.seek(self.sector_size)
        self._raw__m_fat = self._io.read_bytes(self.header.size_fat * self.sector_size)
        _io__raw__m_fat = KaitaiStream(BytesIO(self._raw__m_fat))
        self._m_fat = MicrosoftCfb.FatEntries(_io__raw__m_fat, self, self._root)
        self._io.seek(_pos)
        return getattr(self, '_m_fat', None)

    @property
    def sector_size(self):
        if hasattr(self, '_m_sector_size'):
            return self._m_sector_size

        self._m_sector_size = 1 << self.header.sector_shift
        return getattr(self, '_m_sector_size', None)