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Date:   Sun, 24 May 2020 16:44:40 -0700
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Subject: Re: Re: [PATCH v12 00/18] Enable FSGSBASE instructions
To:     Sasha Levin <sashal@kernel.org>
CC:     Thomas Gleixner <tglx@linutronix.de>,
        Don Porter <porter@cs.unc.edu>,
        Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
        Andi Kleen <ak@linux.intel.com>, linux-kernel@vger.kernel.org,
        bp@alien8.de, luto@kernel.org, dave.hansen@intel.com,
        tony.luck@intel.com, ravi.v.shankar@intel.com,
        chang.seok.bae@intel.com
From:   hpa@zytor.com
Message-ID: <F8D68F56-8928-489A-92AD-175048B22A6F@zytor.com>
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On May 24, 2020 2:19:45 PM PDT, Sasha Levin <sashal@kernel=2Eorg> wrote:
>On Sun, May 24, 2020 at 12:45:18PM -0700, hpa@zytor=2Ecom wrote:
>>There are legitimate reasons to write a root-hole module, the main one
>being able to test security features like SMAP=2E I have requested before
>a TAINT flag specifically for this purpose, because TAINT_CRAP is
>nowhere near explicit enough, and is also used for staging drivers=2E
>Call it TAINT_TOXIC or TAINT_ROOTHOLE; it should always be accompanied
>with a CRIT level alert=2E
>
>What I don't like about our current system of TAINT_* flags is that
>while we can improve it as much as we want, no one outside of the
>kernel
>tree seems to be using it=2E While Thomas may have been commenting on
>Graphene's behaviour, look at any other code that did the same thing:
>
>- Graphene:
>https://github=2Ecom/oscarlab/graphene-sgx-driver/blob/master/gsgx=2Ec
>- Occlum:
>https://github=2Ecom/occlum/enable_rdfsbase/blob/master/enable_rdfsbase=
=2Ec
>- SGX-LKL:
>https://github=2Ecom/lsds/sgx-lkl/blob/master/tools/kmod-set-fsgsbase/mod=
_set_cr4_fsgsbase=2Ec
>
>None of which set even the CRAP flag=2E

That's a separate problem, but I would personally want to have it for my o=
wn test modules in case one ever escapes=2E
--=20
Sent from my Android device with K-9 Mail=2E Please excuse my brevity=2E