Comment by url00

5 days ago

When you do a helm pull and download a chart from a repo, I believe it's a tar-ball. So if you have a workflow where you install charts from the filesystem you could be impacted. I've done that in the past.

I can only repeat the assertion: if you have a victim pulling and installing untrusted tarballs, there is no security boundary being crossed.

It doesn't matter whether it's "from a repo". If you can't trust the repo it can feed you whatever it wants.

  • You're not installing the untrusted tarball; helm is merely supposed to be extracting it, and then rendering the templates contained within.

    (Those templates, once rendered, might then refer to pods, etc. that might be put into a k8s cluster (or perhaps we merely render then YAML, and never `apply` it), and in that sense, one might imagine that that is an install, but that's not the security boundary being crossed here; this would presumably result in execution on the host running helm, which would definitely be surprising.)

    • You're quibbling over the meaning of "install" but apparently conceding the part about untrusted? OK, fair enough. I still argue that any process involving the extraction and (ahem) "rendering of contained templates" from untrusted sources is broken in ways a fix for this particular symlink issue isn't going to address.

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