On 10/12/23 12:26, Alistair Francis wrote: > On Tue, 2023-10-03 at 15:39 +0100, Jonathan Cameron wrote: >> On Thu, 28 Sep 2023 19:32:37 +0200 >> Lukas Wunner <lukas@xxxxxxxxx> wrote: >> >>> From: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> >>> >>> The Security Protocol and Data Model (SPDM) allows for >>> authentication, >>> measurement, key exchange and encrypted sessions with devices. >>> >>> A commonly used term for authentication and measurement is >>> attestation. >>> >>> SPDM was conceived by the Distributed Management Task Force (DMTF). >>> Its specification defines a request/response protocol spoken >>> between >>> host and attached devices over a variety of transports: >>> >>> https://www.dmtf.org/dsp/DSP0274 >>> >>> This implementation supports SPDM 1.0 through 1.3 (the latest >>> version). >> >> I've no strong objection in allowing 1.0, but I think we do need >> to control min version accepted somehow as I'm not that keen to get >> security folk analyzing old version... > > Agreed. I'm not sure we even need to support 1.0 > >> >>> It is designed to be transport-agnostic as the kernel already >>> supports >>> two different SPDM-capable transports: >>> >>> * PCIe Data Object Exchange (PCIe r6.1 sec 6.30, drivers/pci/doe.c) >>> * Management Component Transport Protocol (MCTP, >>> Documentation/networking/mctp.rst) >> >> The MCTP side of things is going to be interesting because mostly you >> need to jump through a bunch of hoops (address assignment, routing >> setup >> etc) before you can actually talk to a device. That all involves >> a userspace agent. So I'm not 100% sure how this will all turn out. >> However still makes sense to have a transport agnostic implementation >> as if nothing else it makes it easier to review as keeps us within >> one specification. > > This list will probably expand in the future though > >>> >>> Use cases for SPDM include, but are not limited to: >>> >>> * PCIe Component Measurement and Authentication (PCIe r6.1 sec >>> 6.31) >>> * Compute Express Link (CXL r3.0 sec 14.11.6) >>> * Open Compute Project (Attestation of System Components r1.0) >>> >>> https://www.opencompute.org/documents/attestation-v1-0-20201104-pdf >> >> Alastair, would it make sense to also call out some of the storage >> use cases you are interested in? > > I don't really have anything to add at the moment. I think PCIe CMA > covers the current DOE work Specifications for SPDM encapsulation in SCSI and ATA commands (SECURITY PROTOCOL IN/OUT and TRUSTED SNED/RECEIVE) is being worked on now but that is still in early phases of definition. So that support can come later. I suspect the API may need some modification to accommodate that use case, but we need more complete specification first to clearly see what is needed (if anything at all). -- Damien Le Moal Western Digital Research
