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From:   Andy Lutomirski <luto@kernel.org>
Date:   Thu, 16 May 2019 14:00:13 -0700
Message-ID: <CALCETrXb7R-5Uq5Wg2bS1mGBp5bor78LBAbosOtp3ZCpFMAsrQ@mail.gmail.com>
Subject: Re: SGX vs LSM (Re: [PATCH v20 00/28] Intel SGX1 support)
To:     James Morris <jmorris@namei.org>
Cc:     Andy Lutomirski <luto@kernel.org>,
        Sean Christopherson <sean.j.christopherson@intel.com>,
        "Serge E. Hallyn" <serge@hallyn.com>,
        LSM List <linux-security-module@vger.kernel.org>,
        Paul Moore <paul@paul-moore.com>,
        Stephen Smalley <sds@tycho.nsa.gov>,
        Eric Paris <eparis@parisplace.org>, selinux@vger.kernel.org,
        Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
        Jethro Beekman <jethro@fortanix.com>,
        "Xing, Cedric" <cedric.xing@intel.com>,
        "Hansen, Dave" <dave.hansen@intel.com>,
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> On May 16, 2019, at 12:24 AM, James Morris <jmorris@namei.org> wrote:
>
>> On Wed, 15 May 2019, Andy Lutomirski wrote:
>>
>>> On Wed, May 15, 2019 at 3:46 PM James Morris <jmorris@namei.org> wrote:
>>>
>>> You could try user.sigstruct, which does not require any privs.
>>>
>>
>> I don't think I understand your proposal.  What file would this
>> attribute be on?  What would consume it?
>
> It would be on the enclave file, so you keep the sigstruct bound to it,
> rather than needing a separate file to manage.  It would simplify any LSM
> policy check.
>
> It would be consumed by (I guess) the SGX_INIT_THE_ENCLAVE ioctl in your
> example, instead of having a 2nd fd.
>
>

Okay, I think I see what you=E2=80=99re suggesting. I don=E2=80=99t think i=
t works
well, though, since loading the data from the enclave file will almost
always be done in multiple chunks, and it=E2=80=99s not clear when the kern=
el
should look for the xattr or what to do if the xattr changes part way
through.