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redhat-support-tool: Python tarfile extraction needs change to avoid a warning

    • redhat-support-tool-0.14.1-0.el8_9
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      Hello,
      In RHEL 9.3 and 8.9, we're planning to fix the long-standing CVE-2007-4559: Python's `tarfile` module makes it too easy to extract tarballs in an unsafe way.
      Unfortunately, for the CVE to be considered fixed, this needs a behavior change. (If you don't think this is the case, let's bring it up with the security team.)
      Upstream, Python will emit deprecation warnings for 2 releases, but in RHEL we change the behavior now, emit warnings, and provide ways for customers to restore earlier behavior.
      To avoid the warning, software shipped by Red Hat will need a change.

      For more details see upstream PEP 706: https://peps.python.org/pep-0706
      and the Red Hat knowledge base draft: https://access.redhat.com/articles/7004769

      In /usr/lib/python3.6/site-packages/redhat_support_tool/helpers/soscleaner.py, redhat-support-tool calls `p.extractall()`. The call will emit a warning by default. Something like this should be added before the call:

      p.extraction_filter = getattr(tarfile, 'data_filter',
      (lambda member, path: member))

      This is compatible with unpatched versions of Python. If you only build for RHEL8.9+, instead add an argument to the call:
      p.extractall(self.origin_path, filter='data')

      The 'data_filter' above attempts a "safe" extraction, intended for pure data archives. For example:

      • prevents extracting outside the target directory, and to absolute paths (by raising an exception)
      • prevents symlinks pointing outside the target directory, and to absolute paths
      • adjusts permissions (for the owner, only the executable bit is honored)
        See PEP 706 for details: https://peps.python.org/pep-0706/#filters

      You can additionally set `p.errorlevel = 0` to skip extracting "bad" files with a warning on stderr.

      If you trust the tarball, use `'fully_trusted_filter'` (or `filter='fully_trusted'`) instead. That will preserve the existing behavior.

      Let me know if you have any questions!

            rhn-support-pghole Pranita Ghole
            pviktori@redhat.com Petr Viktorin (Inactive)
            Pranita Ghole Pranita Ghole
            Miroslav Hradilek Miroslav Hradilek
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