Helm local code execution via a malicious chart

Is the vulnerability that you ship a chart with `Chart.lock -> ../.bashrc`, and then helm writes to `Chart.lock`?

Why is the fix specific to Chart.lock (https://github.com/helm/helm/commit/76fdba4c8c2a4829a6b7abb4...), wouldn't the fix be instead that "A chart cannot contain any symlinks outside of its root"?

I agree that it's not clearly explained why this isn't a concern though. A cursory search for other instances of os.WriteFile doesn't seem to surface any thorough controls...

edit: ok actually it looks like the lockfile is special because it's the only instance of helm itself directly writing a file on behalf of a package consumer

If you have a chart that has `deploy.yaml` symlinked to `/home/john/testcharts/redis/deploy.yaml`, that chart is clearly not going to work on anyone's machine except john's, so that chart is useless on anyone else's machine.

If you're saying the use-case is for charts that aren't distributed, well, I'm saying we should ban all symlinks on distribution (downloading and unpacking a chart should fail if it has symlinks outside of the root), and I just can't imagine any use-case where a distributed chart with external symlinks makes sense.

If this whole thing is about charts that aren't distributed, but local to some developer's machine, well, in that case who cares if the developer can pwn themselves by typing "ln -s ~/.bashrc Chart.lock", they could have just pwned themselves by typing "bash" even more quickly.