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Comment by amluto | Hacker News Reader

Interesting question: should Linux enable non-debug enclaves at all as long as this policy remains in place?

I expect this to play out like the W3C EME standard. Software attestation separates debug from non-debug enclaves, so your kernel will need to load production enclaves for you to watch Netflix. If Mozilla/Firefox caved, so will Linux.

That'd be a ridiculous sort of circular-DRM move that helps nobody, so, no.

One of the primary use cases for this technology is cloud computing. Amazon, Google, etc are all quite capable of patching such checks out of the kernel if they want to use SGX. All it'd do is annoy a few engineers at these companies. Likewise, for deployments on the client, it's really only the Microsoft and Apple kernel devs that matter given the Linux communities tiny desktop market share, and I don't see why they would do that.

So there's absolutely no reason not to implement DRM, ever, because it doesn't help anybody? Abstaining from implementing a feature you don't agree with, especially from an open source program licensed under the GPL, is certainly a worthwhile move. It at the very least communicates that you don't agree with the feature, and forces others to think about the issue deeper to e.g. apply a patch to use it. SGX is the anti-thesis of the GPL and what Stallman has been warning about for years: software that you are physically incapable of debugging, reading, or modifying. And that's scary.

Of course, it's silly if you think the kernel won't accept a patch for SGX on moral grounds. It already has several modules for DRM technologies, along with binary blobs for drivers. But it's nice to think about.

Why is it nice to think about? It'd be a move as pointless and self-destructive as GCC refusing to implement a usable IR because of Stallman's belief that it'd hurt free software. End result: LLVM is now replacing GCC as the de-facto compiler toolchain of choice.

SGX is an optional feature. It doesn't magically run software against your will and it is not "immoral". Ascribing moral positions to CPU features seems ridiculous to me, sort of like describing a pickaxe as "immoral". If you don't want to use it, then don't execute software that includes SGX instructions. If you do want to use it, then all Linux getting in your way will do is convince you that maybe you should be using a different kernel whilst you wait for Intel's own driver to compile and install.

This stance ignores what happens when people are complacent over the long term. If we make it easy to run SGX instructions, that will encourage its use by developers, which leads to more closed source dependence.

There's some support in Intel's Management Engine for DRM, called Intel Insider (the successor of PAVP). One of the SGX papers mentions plans for hooking up SGX enclaves with PAVP.

Based on public docs, you can't do DRM decoding in an enclave. But you can execute some complex logic to validate a user's license and decide whether you want to release the encryption key to the ME or GPU.

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