Python3 compatibility

[rsaccani]

Python 3 compatibility

Full port of ExeFilter from Python 2 to Python 3. All core scanner
functionality is working and tested against the included demo files
(26 files analyzed: 7 clean, 14 cleaned, 5 blocked, 0 errors).

Changes

Syntax

• print statements → print() calls
• raise X, msg → raise X(msg)
• except X, e → except X as e
• Octal literals: 0755 → 0o755
• Long integer literals: 0xFFFFFFFFL → 0xFFFFFFFL

Standard library renames

• ConfigParser → configparser
• StringIO → io / io.BytesIO
• Queue → queue
• urlparse → urllib.parse
• HTMLParser / htmlentitydefs → html.parser / html.entities
• string.join → str.join

bytes vs str

• Binary file parsing updated throughout to use bytes literals (b"...")
• debut.startswith(...) and debut.find(...) calls use bytes arguments
• Socket send/recv in pyclamd encoded/decoded at the boundary
• base64 module replaces .decode('base64') string method

Imports

• Implicit relative imports in the Filtres/ package replaced with
  explicit from . import Filtre syntax (required by Python 3)
• from HTML import * → from .HTML import *

Key modules

• OleFileIO_PL: StringIO → io.BytesIO, i16/i32 via
  struct.unpack_from, __cmp__ → __lt__, has_key → in
• pdfid_PL: binary read loop, b"" EOF check, bytes writes
• path.py: basestring → str, file → open, octal literals
• plx.py: unistr/str_lat1 updated for Python 3 str/bytes model
• RechercherRemplacer: str/bytes regex normalization in Motif.__init__
• cherrypy wsgiserver: queue, io, urllib.parse, exec statement
  syntax, 3-argument raise replaced

Testing

Tested with python3 ExeFilter.py -b demo_files/:

File	Result
Word 2003 normal.doc	Allowed and clean
Word 2003 VBA macro.doc	Contains active content that can be cleaned
Word 2003 OLE Package EXE.doc	Cannot be analyzed or cleaned
PDF Launch calc.pdf	Contains active content that can be cleaned
RTF OLE Package EXE.rtf	Contains active content that can be cleaned
GIF Picture.gif	Allowed and clean
Zipped JPEG and EXE.zip	Contains active content that can be cleaned
HTML normal.html	Allowed and clean
*.exe	File extension not allowed

Notes

• xfweb.py / CherryProxy depends on rfc822 and socket._fileobject
  which were removed in Python 3. The HTTP proxy mode is not functional
  in Python 3; the core file scanner (ExeFilter.py) is fully working.
• Files retain their original iso-8859-1 encoding declaration.