Re: [PATCH 0/6] Intel Secure Guard Extensions

[Jarkko Sakkinen]

On Wed, Apr 27, 2016 at 10:18:05AM +0200, Ingo Molnar wrote:
> 
> * Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote:
> 
> > > What new syscalls would be needed for ssh to get all this support?
> > 
> > This patchset or similar, plus some user code and an enclave to use.
> > 
> > Sadly, on current CPUs, you also need Intel to bless the enclave.  It looks like 
> > new CPUs might relax that requirement.
> 
> That looks like a fundamental technical limitation in my book - to an open source 
> user this is essentially a very similar capability as tboot: it only allows the 
> execution of externally blessed static binary blobs...
> 
> I don't think we can merge any of this upstream until it's clear that the hardware 
> owner running open-source user-space can also freely define/start his own secure 
> enclaves without having to sign the enclave with any external party. I.e. 
> self-signed enclaves should be fundamentally supported as well.

Post Skylake we will have a set of MSRs for defining your own root of
trust: IA32_SGXLEPUBKEYHASH.

Andy had a concern that you could set root of trust multiple times,
which could lead to potential attack scenarios. These MSRs are one-shot.
ENCLS will fail if the launch control is locked. There's no possiblity
to have a root of trust that is unlocked.

> Thanks,
> 
> 	Ingo

/Jarkko