CVE-2007-4559 Patch

[TrellixVulnTeam]

Patching CVE-2007-4559

Hi, we are security researchers from the Advanced Research Center at Trellix. We have began a campaign to patch a widespread bug named CVE-2007-4559. CVE-2007-4559 is a 15 year old bug in the Python tarfile package. By using extract() or extractall() on a tarfile object without sanitizing input, a maliciously crafted .tar file could perform a directory path traversal attack. We found at least one unsantized extractall() in your codebase and are providing a patch for you via pull request. The patch essentially checks to see if all tarfile members will be extracted safely and throws an exception otherwise. We encourage you to use this patch or your own solution to secure against CVE-2007-4559. Further technical information about the vulnerability can be found in this blog.

If you have further questions you may contact us through this projects lead researcher Kasimir Schulz.

[langston-barrett]

• It would be good to extract these helpers to the top level to avoid redefining them every time this function is executed.
• Each helper should have a docstring that specifies what it does, possibly linking to the CVE
• The exception should also mention this CVE, and should probably be a more specific class than Exception in order to make it possible to catch it without catching all exceptions
• Each helper should have Mypy type annotations for parameters and return values

I assume that this was an automated pull request and will not be updated to reflect these changes; it's possible that I will make these changes at some point.