Messages in this thread | | | Date | Tue, 9 Jan 2018 15:54:22 +0100 | From | Willy Tarreau <> | Subject | Re: [RFC PATCH v2 2/6] x86/arch_prctl: add ARCH_GET_NOPTI and ARCH_SET_NOPTI to enable/disable PTI |
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On Tue, Jan 09, 2018 at 03:51:57PM +0100, Borislav Petkov wrote: > On Tue, Jan 09, 2018 at 03:36:53PM +0100, Willy Tarreau wrote: > > I see and am not particularly against this, but what use case do you > > have in mind precisely ? I doubt it's just saving a few tens of bytes, > > so probably you're more concerned about the potential risks this opens ? > > But given we only allow this for CAP_SYS_RAWIO and these ones already > > have access to /dev/mem and many other things, don't you think there > > are much easier ways to dump kernel memory in this case than trying to > > inject some meltdown code into the victim process ? Or maybe you have > > other cases in mind that I'm not seeing. > > I'd like this to be config-controllable so that distros can make the > decision whether/if they want to support the whole per-mm thing.
OK.
> Also, if CAP_SYS_RAWIO is going to protect, please make the > ARCH_GET_NOPTI variant check it too.
Interestingly I removed the check consecutive to the discussions. But I think I'll simply remove the whole ARCH_GET_NOPTI as it has no real value beyond initial development.
Willy
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