Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
IronPort-SDR: a2u74Y+AetCqB2LUqrv99fQwSvr3qsOo1g6PEdKPg8FhcSSS/xTjprhKqM5oWAOMhw4CQOJZ0L
 V+OtZ7GU6C3Q==
IronPort-SDR: bbCSE4/R5ayvoWbafEt20soFZkpybG7fXU9p/ubQc1UiSKUuDr3enPuYHx8dSLInapesEHv0rP
 nGlckWlwbUrg==
Date:   Fri, 25 Sep 2020 00:58:15 +0300
From:   Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To:     Sean Christopherson <sean.j.christopherson@intel.com>
Cc:     Haitao Huang <haitao.huang@linux.intel.com>,
        Andy Lutomirski <luto@kernel.org>, X86 ML <x86@kernel.org>,
        linux-sgx@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
        Linux-MM <linux-mm@kvack.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Matthew Wilcox <willy@infradead.org>,
        Jethro Beekman <jethro@fortanix.com>,
        Darren Kenny <darren.kenny@oracle.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        asapek@google.com, Borislav Petkov <bp@alien8.de>,
        "Xing, Cedric" <cedric.xing@intel.com>, chenalexchen@google.com,
        Conrad Parker <conradparker@google.com>, cyhanish@google.com,
        Dave Hansen <dave.hansen@intel.com>,
        "Huang, Haitao" <haitao.huang@intel.com>,
        Josh Triplett <josh@joshtriplett.org>,
        "Huang, Kai" <kai.huang@intel.com>,
        "Svahn, Kai" <kai.svahn@intel.com>, Keith Moyer <kmoy@google.com>,
        Christian Ludloff <ludloff@google.com>,
        Neil Horman <nhorman@redhat.com>,
        Nathaniel McCallum <npmccallum@redhat.com>,
        Patrick Uiterwijk <puiterwijk@redhat.com>,
        David Rientjes <rientjes@google.com>,
        Thomas Gleixner <tglx@linutronix.de>, yaozhangx@google.com
Subject: Re: [PATCH v38 10/24] mm: Add vm_ops->mprotect()
Message-ID: <20200924215815.GB119995@linux.intel.com>
References: <20200921124946.GF6038@linux.intel.com>
 <20200921165758.GA24156@linux.intel.com>
 <20200921210736.GB58176@linux.intel.com>
 <20200921211849.GA25403@linux.intel.com>
 <20200922052957.GA97272@linux.intel.com>
 <20200922053515.GA97687@linux.intel.com>
 <20200922164301.GB30874@linux.intel.com>
 <20200923135056.GD5160@linux.intel.com>
 <op.0rgp5h0hwjvjmi@mqcpg7oapc828.gar.corp.intel.com>
 <20200924192853.GA18826@linux.intel.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20200924192853.GA18826@linux.intel.com>
Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo
Precedence: bulk

On Thu, Sep 24, 2020 at 12:28:54PM -0700, Sean Christopherson wrote:
> On Thu, Sep 24, 2020 at 02:11:37PM -0500, Haitao Huang wrote:
> > On Wed, 23 Sep 2020 08:50:56 -0500, Jarkko Sakkinen
> > <jarkko.sakkinen@linux.intel.com> wrote:
> > >I'll categorically deny noexec in the next patch set version.
> > >
> > >/Jarkko
> > 
> > There are use cases supported currently in which enclave binary is received
> > via IPC/RPC and held in buffers before EADD. Denying noexec altogether would
> > break those, right?
> 
> No.  noexec only applies to file-backed VMAs, what you're describing is loading
> an enclave from an anon VMA, which will still have VM_MAYEXEC.
> 
> I believe you're thinking of SELinux's EXECMEM, which is required to execute
> from anonymous memory, and which we talked about (more than once) applying to
> SGX enclaves.
> 
> That being said, I still dislike the idea of requiring VM_MAYEXEC, it's a hack
> that doesn't really buy us much, if anything.

I think it makes sense as long as it is not half-way there solution.

Either require it for the full binary or not at all. I'm fine with
either.

/Jarkko