Subject: Re: Avoid speculative indirect calls in kernel
To: Willy Tarreau <w@1wt.eu>, Thomas Gleixner <tglx@linutronix.de>
References: <20180103230934.15788-1-andi@firstfloor.org>
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Cc: Jon Masters <jcm@redhat.com>,
        "Woodhouse, David" <dwmw@amazon.co.uk>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Alan Cox <gnomes@lxorguk.ukuu.org.uk>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Andi Kleen <andi@firstfloor.org>,
        Greg Kroah-Hartman <gregkh@linux-foundation.org>,
        Tim Chen <tim.c.chen@linux.intel.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Jeff Law <law@redhat.com>, Nick Clifton <nickc@redhat.com>
From: Dave Hansen <dave.hansen@intel.com>
Message-ID: <44f1b753-47d3-82e3-9401-256b4beadd4f@intel.com>
Date: Thu, 4 Jan 2018 22:57:19 -0800
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On 01/04/2018 10:49 PM, Willy Tarreau wrote:
> On Fri, Jan 05, 2018 at 01:54:13AM +0100, Thomas Gleixner wrote:
>> On Thu, 4 Jan 2018, Jon Masters wrote:
>>> P.S. I've an internal document where I've been tracking "nice to haves"
>>> for later, and one of them is whether it makes sense to tag binaries as
>>> "trusted" (e.g. extended attribute, label, whatever). It was something I
>>> wanted to bring up at some point as potentially worth considering.
>> Scratch that. There is no such thing as a trusted binary.
> I disagree with you on this Thomas. "trusted" means "we agree to share the
> risk this binary takes because it's critical to our service". When you
> build a load balancing appliance on which 100% of the service is assured
> by a single executable and the rest is just config management, you'd better
> trust that process.

So you want to run this "one binary" as fast as possible and without
mitigations in place?  But, you want mitigations *available* on that
system at the same time?  For what?  If there's only one binary, why not
just disable the mitigations entirely?