Messages in this thread | | | Subject | Re: [PATCH v6 11/10] x86/retpoline: Avoid return buffer underflows on context switch | From | David Woodhouse <> | Date | Tue, 09 Jan 2018 13:04:20 +0000 |
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On Mon, 2018-01-08 at 19:27 -0800, Andy Lutomirski wrote: > > > > If SMEP is not active, speculation can go anywhere, including to a user > > controlled gadget which can reload any registers it needs, including > > with immediate constants. > > I thought that, even on pre-SMEP hardware, the CPU wouldn't > speculatively execute from NX pages. And PTI marks user memory NX > in kernel mode.
Hm, now that could be useful.
Do *all* the KPTI backports (some of which are reimplementations rather than strictly backports) mark user memory NX?[unhandled content-type:application/x-pkcs7-signature] | |