Messages in this thread |  | | Date | Mon, 8 Jan 2018 16:44:15 -0800 | From | Andi Kleen <> | Subject | Re: [PATCH v6 11/10] x86/retpoline: Avoid return buffer underflows on context switch |
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> So I was really hoping that in places like context switching etc, we'd > be able to instead effectively kill off any exploits by clearing > registers. > > That should make it pretty damn hard to then find a matching "gadget" > that actually does anything interesting/powerful. > > Together with Spectre already being pretty hard to take advantage of, > and the eBPF people making those user-proivided gadgets inaccessible, > it really should be a pretty powerful fix. > > Hmm?
Essentially the RSB are hidden registers, and the only way to clear them is the FILL_RETURN_BUFFER sequence. I don't see how clearing anything else would help?
-Andi
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