Re: [PATCH v5 08/11] intel_sgx: in-kernel launch enclave

Jarkko Sakkinen
2017-11-20T23:43:45Z

On Mon, Nov 20, 2017 at 11:43:22PM +0100, Thomas Gleixner wrote:
> On Tue, 21 Nov 2017, Jarkko Sakkinen wrote:
> > On Wed, Nov 15, 2017 at 12:50:06PM +0100, Peter Zijlstra wrote:
> > > On Mon, Nov 13, 2017 at 09:45:25PM +0200, Jarkko Sakkinen wrote:
> > > > TinyCrypt (https://github.com/01org/tinycrypt) is used as AES
> > > > implementation, which is not timing resistant. Eventually this needs to
> > > > be replaced with AES-NI based implementation that could be either
> > >
> > > > - re-use existing AES-NI code in the kernel
> > >
> > > This. That is an absolute must. We're not going to merge custom AES
> > > implementations.
> >
> > I'll post v6 update without update to this in order to get otherwise
> > improved version out and work on it for v7.
> >
> > My initial idea to sort this out would be to try to compile
> >
> > arch/x86/crypto/aesni-intel_asm.S
> >
> > as part of the enclave binary and use it to run AES-256.
>
> No. The kernel has a crypto API.

But you cannot call it from inside an enclave. A syscall will exit the
enclave. The launch enclave requires AES-256 to be executed inside the
enclave.

/Jarkko