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    SubjectRe: [RFC PATCH v2 6/6] x86/entry/pti: don't switch PGD on when pti_disable is set

    * Andy Lutomirski <luto@amacapital.net> wrote:

    > > Oh, and yes, I think the npti flag should also break ptrace(). I do agree with
    > > Andy that it's a "capability", although I do not think it should actually be
    > > implemented as one.
    >
    > For all that Linux capabilities are crap, nopti walks like one and quacks like
    > one. It needs to affect ptrace() permissions, it needs a way to disable it
    > systemwide, it needs LSM integration, etc. Using CAP_DISABLE_PTI gives us all
    > of this without tons of churn, auditing, and a whole new configuration thingy
    > for each LSM. And I avoids permanently polluting ptrace checks, the LSM
    > interface, etc for what is, essentially, a performance hack to work around a
    > blatant error in the design of some CPUs.
    >
    > Plus, with ambient caps, we already did the nasty part of the with and finished
    > all the relevant bikeshedding.
    >
    > So I'd rather just hold my nose and add the new capability bit.

    Those all seem pretty valid arguments to me.

    Thanks,

    Ingo

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