Arbitrary file write during tarfile extraction in luigi/contrib/lsf_runner.py

[Ali-Razmjoo]

Hi,

I am reporting a potential security issue with arbitrary file write during tarfile extraction in
https://github.com/spotify/luigi/blob/master/luigi/contrib/lsf_runner.py#L55-L58

Extracting files from a malicious tar archive without validating that the destination file path is within the destination directory can cause files outside the destination directory to be overwritten, due to the possible presence of directory traversal elements (..) in archive paths.

• ..\malicious_file
• c:\malicious_file
• /etc/passwd

Recommendation

with tarfile.open(sys.argv[1]) as tar:
    for entry in tar:
        #GOOD: Check that entry is safe
        if os.path.isabs(entry.name) or ".." in entry.name:
            raise ValueError("Illegal tar archive entry")
        tar.extract(entry, "/tmp/unpack/")

References

• Snyk: Zip Slip Vulnerability
• OWASP: Path Traversal
• Python Library Reference: TarFile.extract
• Python Library Reference: TarFile.extractall
• Common Weakness Enumeration: CWE-22