CVE-2007-4559 Patch (tarfile path traversal attack) #161
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mara004
changed the title
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Hmm, thank you for notifying me about this... Luckily, this is only in setup code, so wheel users are not impacted (and the tars we work with only come from pdfium-binaries, so we're more or less safe as long as this project is not compromised). But the patch you are suggesting is not particularly nice - two nested function definitions (and that inside a loop). |
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See also https://bugzilla.redhat.com/show_bug.cgi?id=263261#c7, python/cpython#73974, and https://gist.github.com/Kasimir123/9bdc38f2eac9a19f83ef6cc52c7ce82e. |
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I have now implemented a fix based on the patch you suggested. Thanks! |
| abs_directory = os.path.abspath(directory) | ||
| abs_target = os.path.abspath(target) | ||
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| prefix = os.path.commonprefix([abs_directory, abs_target]) |
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should be os.path.commonpath(), see 2bf200a
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.