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Date:   Tue, 14 May 2019 13:43:23 +0300
From:   Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To:     Andy Lutomirski <luto@kernel.org>
Cc:     Jethro Beekman <jethro@fortanix.com>,
        "Xing, Cedric" <cedric.xing@intel.com>,
        "Hansen, Dave" <dave.hansen@intel.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        "Dr. Greg" <greg@enjellic.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        LKML <linux-kernel@vger.kernel.org>, X86 ML <x86@kernel.org>,
        "linux-sgx@vger.kernel.org" <linux-sgx@vger.kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        "Christopherson, Sean J" <sean.j.christopherson@intel.com>,
        "nhorman@redhat.com" <nhorman@redhat.com>,
        "npmccallum@redhat.com" <npmccallum@redhat.com>,
        "Ayoun, Serge" <serge.ayoun@intel.com>,
        "Katz-zamir, Shay" <shay.katz-zamir@intel.com>,
        "Huang, Haitao" <haitao.huang@intel.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        "Svahn, Kai" <kai.svahn@intel.com>, Borislav Petkov <bp@alien8.de>,
        Josh Triplett <josh@joshtriplett.org>,
        "Huang, Kai" <kai.huang@intel.com>,
        David Rientjes <rientjes@google.com>
Subject: Re: [PATCH v20 00/28] Intel SGX1 support
Message-ID: <20190514104323.GA7591@linux.intel.com>
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On Mon, May 13, 2019 at 01:29:26PM +0300, Jarkko Sakkinen wrote:
> I did study through SDK's file format and realized that it does not
> does make sense after all to embed one.
> 
> To implement it properly you would probably need a new syscall (lets say
> sgx_load_enclave) and also that enclaves are not just executables
> binaries. It is hard to find a generic format for them as applications
> range from simply protecting part of an application to running a
> containter inside enclave.


When I looked at SDK's data structures embedded to the ELF they contain
data that is also used by the run-time. Thus, run-time would anyway need
to also parse the file containing the enclave.

There is not same way a single rigid structure of what executable means
as for normal application and in many cases enclave could be just used
to seal a portion of the code. In extreme case you might construct
enclave even on run-time.

I think SIGSTRUCT in a file is the right choice. It is the lowest common
denominator for enclaves that locks in its contents and is same for any
enclave. Practicing access control to that file should be enough to
define whatever security policy required.

I'm still puzzling what kind of changes you were discussing considering
SGX_IOC_ENCLAVE_ADD_PAGE.

/Jarkko