I agree that it wouldn’t stop this library from injecting backdoors into decompressed executables. But I still think it would be a big help anyway. It would stop this attack from working.

At the big picture, we need to acknowledge that we can’t implicitly trust opensource libraries on the internet. They are written by strangers, and if you wouldn’t invite them into your home you shouldn’t give them permission to execute arbitrary code with user level permissions on your computer.

I don’t think there are any one size fits all answers here. And I can’t see a way to make your “tainted output” idea work. But even so, cutting down the trusted surface area from “leftpad can cryptolocker your computer” to “Leftpad could return bad output” sounds like it would move us in the right direction.

And by scratch I mean "without modern hardware" given supply chain attacks also apply to the hardware you build from.

We (obviously) put too much trust in little libraries like xz. I don't see a world in which people start using fewer dependencies in their projects. So given that, I think anything which makes 3rd party dependencies safer than they are now is a good thing. Hence the proposal.

The downside is it adds more complexity. Is that complexity worth it? Hard to say. Thats still worth talking about.

there are some researches on the right track already https://www.se.cs.uni-saarland.de/projects/congruence/