mirror of https://github.com/CIRCL/PyCIRCLean
454 lines
17 KiB
Python
454 lines
17 KiB
Python
#!/usr/bin/env python
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# -*- coding: utf-8 -*-
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import os
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import mimetypes
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import shlex
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import subprocess
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import time
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import zipfile
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import oletools.oleid
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import olefile
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import officedissector
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from pdfid import PDFiD, cPDFiD
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from kittengroomer import FileBase, KittenGroomerBase, main
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SEVENZ = '/usr/bin/7z'
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# Prepare application/<subtype>
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mimes_ooxml = ['vnd.openxmlformats-officedocument.']
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mimes_office = ['msword', 'vnd.ms-']
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mimes_libreoffice = ['vnd.oasis.opendocument']
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mimes_rtf = ['rtf', 'richtext']
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mimes_pdf = ['pdf', 'postscript']
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mimes_xml = ['xml']
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mimes_ms = ['dosexec']
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mimes_compressed = ['zip', 'rar', 'bzip2', 'lzip', 'lzma', 'lzop',
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'xz', 'compress', 'gzip', 'tar']
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mimes_data = ['octet-stream']
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# Aliases
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aliases = {
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# Win executables
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'application/x-msdos-program': 'application/x-dosexec',
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'application/x-dosexec': 'application/x-msdos-program'
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}
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# Sometimes, mimetypes.guess_type is giving unexpected results, such as for the .tar.gz files:
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# In [12]: mimetypes.guess_type('toot.tar.gz', strict=False)
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# Out[12]: ('application/x-tar', 'gzip')
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# It works as expected if you do mimetypes.guess_type('application/gzip', strict=False)
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propertype = {'.gz': 'application/gzip'}
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# Commonly used malicious extensions
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# Sources: http://www.howtogeek.com/137270/50-file-extensions-that-are-potentially-dangerous-on-windows/
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mal_ext = (
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# Applications
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".exe", ".pif", ".application", ".gadget", ".msi", ".msp", ".com", ".scr",
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".hta", ".cpl", ".msc", ".jar",
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# Scripts
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".bat", ".cmd", ".vb", ".vbs", ".vbe", ".js", ".jse", ".ws", ".wsf",
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".wsc", ".wsh", ".ps1", ".ps1xml", ".ps2", ".ps2xml", ".psc1", ".psc2",
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".msh", ".msh1", ".msh2", ".mshxml", ".msh1xml", ".msh2xml",
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# Shortcuts
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".scf", ".lnk", ".inf",
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# Other
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".reg", "dll",
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# Office macro (OOXML with macro enabled)
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".docm", ".dotm", ".xlsm", ".xltm", ".xlam", ".pptm", ".potm", ".ppam",
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".ppsm", ".sldm",)
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class File(FileBase):
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def __init__(self, src_path, dst_path):
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''' Init file object, set the mimetype '''
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super(File, self).__init__(src_path, dst_path)
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self.is_recursive = False
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if not self.has_mimetype():
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# No mimetype, should not happen.
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self.make_dangerous()
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if not self.has_extension():
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self.make_dangerous()
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if self.extension in mal_ext:
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self.log_details.update({'malicious_extension': self.extension})
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self.make_dangerous()
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if self.is_dangerous():
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return
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self.log_details.update({'maintype': self.main_type,
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'subtype': self.sub_type,
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'extension': self.extension})
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# Check correlation known extension => actual mime type
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if propertype.get(self.extension) is not None:
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expected_mimetype = propertype.get(self.extension)
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else:
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expected_mimetype, encoding = mimetypes.guess_type(self.src_path, strict=False)
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if aliases.get(expected_mimetype) is not None:
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expected_mimetype = aliases.get(expected_mimetype)
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is_known_extension = self.extension in mimetypes.types_map.keys()
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if is_known_extension and expected_mimetype != self.mimetype:
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self.log_details.update({'expected_mimetype': expected_mimetype})
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self.make_dangerous()
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# check correlation actual mime type => known extensions
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if aliases.get(self.mimetype) is not None:
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mimetype = aliases.get(self.mimetype)
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else:
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mimetype = self.mimetype
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expected_extensions = mimetypes.guess_all_extensions(mimetype, strict=False)
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if expected_extensions:
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if len(self.extension) > 0 and self.extension not in expected_extensions:
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self.log_details.update({'expected_extensions': expected_extensions})
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self.make_dangerous()
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else:
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# there are no known extensions associated to this mimetype.
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pass
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class KittenGroomerFileCheck(KittenGroomerBase):
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def __init__(self, root_src=None, root_dst=None, max_recursive=5, debug=False):
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'''
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Initialize the basics of the conversion process
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'''
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if root_src is None:
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root_src = os.path.join(os.sep, 'media', 'src')
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if root_dst is None:
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root_dst = os.path.join(os.sep, 'media', 'dst')
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super(KittenGroomerFileCheck, self).__init__(root_src, root_dst, debug)
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self.recursive = 0
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self.max_recursive = max_recursive
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subtypes_apps = [
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(mimes_office, self._winoffice),
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(mimes_ooxml, self._ooxml),
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(mimes_rtf, self.text),
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(mimes_libreoffice, self._libreoffice),
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(mimes_pdf, self._pdf),
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(mimes_xml, self.text),
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(mimes_ms, self._executables),
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(mimes_compressed, self._archive),
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(mimes_data, self._binary_app),
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]
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self.subtypes_application = self._init_subtypes_application(subtypes_apps)
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self.mime_processing_options = {
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'text': self.text,
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'audio': self.audio,
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'image': self.image,
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'video': self.video,
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'application': self.application,
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'example': self.example,
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'message': self.message,
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'model': self.model,
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'multipart': self.multipart,
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'inode': self.inode,
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}
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# ##### Helpers #####
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def _init_subtypes_application(self, subtypes_application):
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'''
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Create the Dict to pick the right function based on the sub mime type
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'''
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to_return = {}
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for list_subtypes, fct in subtypes_application:
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for st in list_subtypes:
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to_return[st] = fct
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return to_return
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def _print_log(self):
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'''
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Print the logs related to the current file being processed
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'''
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tmp_log = self.log_name.fields(**self.cur_file.log_details)
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if self.cur_file.is_dangerous():
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tmp_log.warning(self.cur_file.log_string)
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elif self.cur_file.log_details.get('unknown') or self.cur_file.log_details.get('binary'):
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tmp_log.info(self.cur_file.log_string)
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else:
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tmp_log.debug(self.cur_file.log_string)
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def _run_process(self, command_line, timeout=0, background=False):
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'''Run subprocess, wait until it finishes'''
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if timeout != 0:
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deadline = time.time() + timeout
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else:
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deadline = None
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args = shlex.split(command_line)
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with open(self.log_debug_err, 'ab') as stderr, open(self.log_debug_out, 'ab') as stdout:
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p = subprocess.Popen(args, stdout=stdout, stderr=stderr)
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if background:
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# This timer is here to make sure the unoconv listener is properly started.
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time.sleep(10)
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return True
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while True:
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code = p.poll()
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if code is not None:
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break
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if deadline is not None and time.time() > deadline:
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p.kill()
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break
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time.sleep(1)
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return True
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#######################
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# ##### Discarded mime types, reason in the comments ######
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def inode(self):
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''' Usually empty file. No reason (?) to copy it on the dest key'''
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self.cur_file.log_string += 'Inode file'
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def unknown(self):
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''' This main type is unknown, that should not happen '''
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self.cur_file.log_string += 'Unknown file'
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# ##### Threated as malicious, no reason to have it on a USB key ######
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def example(self):
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'''Way to process example file'''
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self.cur_file.log_string += 'Example file'
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self.cur_file.make_dangerous()
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self._safe_copy()
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def message(self):
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'''Way to process message file'''
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self.cur_file.log_string += 'Message file'
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self.cur_file.make_dangerous()
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self._safe_copy()
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def model(self):
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'''Way to process model file'''
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self.cur_file.log_string += 'Model file'
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self.cur_file.make_dangerous()
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self._safe_copy()
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def multipart(self):
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'''Way to process multipart file'''
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self.cur_file.log_string += 'Multipart file'
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self.cur_file.make_dangerous()
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self._safe_copy()
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#######################
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# ##### Converted ######
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def text(self):
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''' LibreOffice should be able to open all the files '''
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for r in mimes_rtf:
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if r in self.cur_file.sub_type:
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self.cur_file.log_string += 'Rich Text file'
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# TODO: need a way to convert it to plain text
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self.cur_file.force_ext('.txt')
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self._safe_copy()
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else:
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self.cur_file.log_string += 'Text file'
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self.cur_file.force_ext('.txt')
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self._safe_copy()
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def application(self):
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''' Everything can be there, using the subtype to decide '''
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for subtype, fct in self.subtypes_application.items():
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if subtype in self.cur_file.sub_type:
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fct()
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self.cur_file.log_string += 'Application file'
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return
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self.cur_file.log_string += 'Unknown Application file'
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self._unknown_app()
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def _executables(self):
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'''Way to process executable file'''
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self.cur_file.add_log_details('processing_type', 'executable')
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self.cur_file.make_dangerous()
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self._safe_copy()
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def _winoffice(self):
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self.cur_file.add_log_details('processing_type', 'WinOffice')
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# Try as if it is a valid document
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oid = oletools.oleid.OleID(self.cur_file.src_path)
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if not olefile.isOleFile(self.cur_file.src_path):
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# Manual processing, may already count as suspicious
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try:
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ole = olefile.OleFileIO(self.cur_file.src_path, raise_defects=olefile.DEFECT_INCORRECT)
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except:
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self.cur_file.add_log_details('not_parsable', True)
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self.cur_file.make_dangerous()
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if ole.parsing_issues:
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self.cur_file.add_log_details('parsing_issues', True)
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self.cur_file.make_dangerous()
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else:
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if ole.exists('macros/vba') or ole.exists('Macros') \
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or ole.exists('_VBA_PROJECT_CUR') or ole.exists('VBA'):
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self.cur_file.add_log_details('macro', True)
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self.cur_file.make_dangerous()
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else:
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indicators = oid.check()
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# Encrypted ban be set by multiple checks on the script
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if oid.encrypted.value:
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self.cur_file.add_log_details('encrypted', True)
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self.cur_file.make_dangerous()
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if oid.macros.value or oid.ole.exists('macros/vba') or oid.ole.exists('Macros') \
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or oid.ole.exists('_VBA_PROJECT_CUR') or oid.ole.exists('VBA'):
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self.cur_file.add_log_details('macro', True)
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self.cur_file.make_dangerous()
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for i in indicators:
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if i._id == 'ObjectPool' and i.value:
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# FIXME: Is it suspicious?
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self.cur_file.add_log_details('objpool', True)
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elif i._id == 'flash' and i.value:
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self.cur_file.add_log_details('flash', True)
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self.cur_file.make_dangerous()
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self._safe_copy()
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def _ooxml(self):
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self.cur_file.add_log_details('processing_type', 'ooxml')
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doc = officedissector.doc.Document(self.cur_file.src_path)
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# There are probably other potentially malicious features:
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# fonts, custom props, custom XML
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if doc.is_macro_enabled or len(doc.features.macros) > 0:
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self.cur_file.add_log_details('macro', True)
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self.cur_file.make_dangerous()
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if len(doc.features.embedded_controls) > 0:
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self.cur_file.add_log_details('activex', True)
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self.cur_file.make_dangerous()
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if len(doc.features.embedded_objects) > 0:
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# Exploited by CVE-2014-4114 (OLE)
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self.cur_file.add_log_details('embedded_obj', True)
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self.cur_file.make_dangerous()
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if len(doc.features.embedded_packages) > 0:
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self.cur_file.add_log_details('embedded_pack', True)
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self.cur_file.make_dangerous()
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self._safe_copy()
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def _libreoffice(self):
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self.cur_file.add_log_details('processing_type', 'libreoffice')
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# As long as there ar no way to do a sanity check on the files => dangerous
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try:
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lodoc = zipfile.ZipFile(self.cur_file.src_path, 'r')
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except:
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self.cur_file.add_log_details('invalid', True)
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self.cur_file.make_dangerous()
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for f in lodoc.infolist():
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fname = f.filename.lower()
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if fname.startswith('script') or fname.startswith('basic') or \
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fname.startswith('object') or fname.endswith('.bin'):
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self.cur_file.add_log_details('macro', True)
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self.cur_file.make_dangerous()
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self._safe_copy()
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def _pdf(self):
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'''Way to process PDF file'''
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self.cur_file.add_log_details('processing_type', 'pdf')
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xmlDoc = PDFiD(self.cur_file.src_path)
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oPDFiD = cPDFiD(xmlDoc, True)
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# TODO: other keywords?
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if oPDFiD.encrypt > 0:
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self.cur_file.add_log_details('encrypted', True)
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self.cur_file.make_dangerous()
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if oPDFiD.js > 0 or oPDFiD.javascript > 0:
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self.cur_file.add_log_details('javascript', True)
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self.cur_file.make_dangerous()
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if oPDFiD.aa > 0 or oPDFiD.openaction > 0:
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self.cur_file.add_log_details('openaction', True)
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self.cur_file.make_dangerous()
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if oPDFiD.richmedia > 0:
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self.cur_file.add_log_details('flash', True)
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self.cur_file.make_dangerous()
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if oPDFiD.launch > 0:
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self.cur_file.add_log_details('launch', True)
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self.cur_file.make_dangerous()
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def _archive(self):
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'''Way to process Archive'''
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self.cur_file.add_log_details('processing_type', 'archive')
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self.cur_file.is_recursive = True
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self.cur_file.log_string += 'Archive extracted, processing content.'
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tmpdir = self.cur_file.dst_path + '_temp'
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self._safe_mkdir(tmpdir)
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extract_command = '{} -p1 x "{}" -o"{}" -bd -aoa'.format(SEVENZ, self.cur_file.src_path, tmpdir)
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self._run_process(extract_command)
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self.recursive += 1
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self.processdir(tmpdir, self.cur_file.dst_path)
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self.recursive -= 1
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self._safe_rmtree(tmpdir)
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def _unknown_app(self):
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'''Way to process an unknown file'''
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self.cur_file.make_unknown()
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self._safe_copy()
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def _binary_app(self):
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'''Way to process an unknown binary file'''
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self.cur_file.make_binary()
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self._safe_copy()
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#######################
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# ##### Not converted, checking the mime type ######
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def audio(self):
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'''Way to process an audio file'''
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self.cur_file.log_string += 'Audio file'
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self._media_processing()
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def image(self):
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'''Way to process an image'''
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self.cur_file.log_string += 'Image file'
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self._media_processing()
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def video(self):
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'''Way to process a video'''
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self.cur_file.log_string += 'Video file'
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self._media_processing()
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def _media_processing(self):
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'''Generic way to process all the media files'''
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self.cur_file.add_log_details('processing_type', 'media')
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self._safe_copy()
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#######################
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def processdir(self, src_dir=None, dst_dir=None):
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'''
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Main function doing the processing
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'''
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if src_dir is None:
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src_dir = self.src_root_dir
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if dst_dir is None:
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dst_dir = self.dst_root_dir
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if self.recursive > 0:
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self._print_log()
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if self.recursive >= self.max_recursive:
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self.cur_log.warning('ARCHIVE BOMB.')
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self.cur_log.warning('The content of the archive contains recursively other archives.')
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self.cur_log.warning('This is a bad sign so the archive is not extracted to the destination key.')
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self._safe_rmtree(src_dir)
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if src_dir.endswith('_temp'):
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archbomb_path = src_dir[:-len('_temp')]
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self._safe_remove(archbomb_path)
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for srcpath in self._list_all_files(src_dir):
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self.cur_file = File(srcpath, srcpath.replace(src_dir, dst_dir))
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self.log_name.info('Processing {} ({}/{})', srcpath.replace(src_dir + '/', ''),
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self.cur_file.main_type, self.cur_file.sub_type)
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if not self.cur_file.is_dangerous():
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self.mime_processing_options.get(self.cur_file.main_type, self.unknown)()
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else:
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self._safe_copy()
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if not self.cur_file.is_recursive:
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self._print_log()
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if __name__ == '__main__':
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main(KittenGroomerFileCheck, 'Generic version of the KittenGroomer. Convert and rename files.')
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