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Subject: Re: [PATCH v20 00/28] Intel SGX1 support
From:   Andy Lutomirski <luto@amacapital.net>
In-Reply-To: <20190515110005.GA14718@linux.intel.com>
Date:   Wed, 15 May 2019 07:27:02 -0700
Cc:     Sean Christopherson <sean.j.christopherson@intel.com>,
        Andy Lutomirski <luto@kernel.org>,
        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>,
        "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>
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References: <8fe520bb-30bd-f246-a3d8-c5443e47a014@intel.com> <358e9b36-230f-eb18-efdb-b472be8438b4@fortanix.com> <960B34DE67B9E140824F1DCDEC400C0F4E886094@ORSMSX116.amr.corp.intel.com> <6da269d8-7ebb-4177-b6a7-50cc5b435cf4@fortanix.com> <CALCETrWCZQwg-TUCm58DVG43=xCKRsMe1tVHrR8vdt06hf4fWA@mail.gmail.com> <20190513102926.GD8743@linux.intel.com> <20190514104323.GA7591@linux.intel.com> <CALCETrVbgTCnPo=PAq0-KoaRwt--urrPzn==quAJ8wodCpkBkw@mail.gmail.com> <20190514204527.GC1977@linux.intel.com> <20190515103531.GB10917@linux.intel.com> <20190515110005.GA14718@linux.intel.com>
To:     Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Sender: linux-kernel-owner@vger.kernel.org
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> On May 15, 2019, at 4:00 AM, Jarkko Sakkinen <jarkko.sakkinen@linux.intel.=
com> wrote:
>=20
>> On Wed, May 15, 2019 at 01:35:31PM +0300, Jarkko Sakkinen wrote:
>> This brings me to an open question in Andy's model: lets say that we
>> change the source for SIGSTRUCT from memory address to fd. How can the
>> policy prevent the use not creating a file containing a SIGSTRUCT and
>> passing fd of that to the EINIT ioctl?
>=20

The policy will presumably check the label on the file that the fd points to=
.

> Also wondering if a path would be better than plain fd for defining a
> reasonable policy i.e. have sigstruct_path as part of the ioctl
> parameters and not sigstruct_fd.
>=20

It would save two syscalls at the cost of a decent amount of complexity.=