README.md

zip_null_patch

A module to enable null characters in zipfile path names.

Motivation

In Python, the built-in zipfile module purposefully rejects paths containing null-byte characters. The reasoning is to prevent unintended behaviour from viruses which abuse null-byte paths in archives.

## CPython 3.6 -- zipfile.py

# Terminate the file name at the first null byte.  Null bytes in file
# names are used as tricks by viruses in archives.
null_byte = filename.find(chr(0))
if null_byte >= 0:
    filename = filename[0:null_byte]

However, if trying to purposefully read a zip created by a malicious program, Python provides no exit-hatch to forcefully enable the parsing of paths containing null-bytes. This means that proper analysis of any null-byte-containing archive is impossible.

Enter: zip_null_patch. Simply call zip_null_patch.patch_zipfile() and the built-in zipfile module will now accept null-bytes!

Usage

>>> import zipfile

>>> info = zipfile.ZipInfo(filename="abc\x00def")
>>> info.filename
'abc'

>>> import zip_null_patch
>>> zip_null_patch.patch_zipfile()

>>> info = zipfile.ZipInfo(filename="abc\x00def")
>>> info.filename
'abc\x00def'