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Versions: 00                                                            
Network Working Group                                        E. Nordmark
Internet-Draft                                                    Zededa
Intended status: Informational                              26 July 2021
Expires: 27 January 2022

          Different aspects of onboarding for IoT/Edge Devices


   Previous onboarding discussions have focused on network onboarding.
   In this note we put that in the context of the larger onboarding
   picture to also discuss the onboarding to some management or
   orchestration system.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
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   This Internet-Draft will expire on 27 January 2022.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  What is onboarding? . . . . . . . . . . . . . . . . . . . . .   2
   3.  IoT vs. Edge Computing? . . . . . . . . . . . . . . . . . . .   3
   4.  Network onboarding  . . . . . . . . . . . . . . . . . . . . .   4
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   6.  Example: Project EVE  . . . . . . . . . . . . . . . . . . . .   5
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   5
   8.  Informative References  . . . . . . . . . . . . . . . . . . .   5
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   The iotops group has discussed LwM2M [oma], FIDO [fidospec] and
   [I-D.lear-iotops-deep-thoughts-on-onboarding] where the last one
   intentionally focuses on network onboarding.  This note broadens the
   discussion to all aspects of onboarding of IoT and edge devices to
   try to expose what is common and different at different layers.

   Some of these topics has previously come up in T2TRG for example in
   [I-D.irtf-t2trg-secure-bootstrapping] but also with a strong
   networking focus.

2.  What is onboarding?

   One aspect of onboarding a device is providing network access to the
   device.  That might involve both L2 and L3 aspects, such as Cellular
   and WiFi credentials at L2 and LAN as Internet access at L3.
   Furthermore, the L3 access might differentiate between LAN and
   Internet access and be subject to access control for instance
   controlled by MUD [RFC8520].

   However, there are also higher levels of onboarding.  For instance,
   Anima supports a notion of Secure Bootstrap over an Unconfigured
   Network [RFC8994] which not only includes the secure keys (BRSKI
   [RFC8995]) but also the configuration of the routers and switches
   (using GRASP [RFC8990]).  Such configuration can have rather wide
   span and one can think of it as consisting of configuring the device
   plus configuring various applications (which might be routing
   protocols and management agents in the case of Anima use cases).

   If we look at more compute-centric workloads are likely to have a
   larger set of applications which might be configured and managed
   separately from the device.  We can already see examples of this in
   cloud datacenters where there is a IaaS layer provisioning and
   managing the servers, which is largely invisible to the users, and a
   set of applications (in the form for virtual machines or containers)

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   which are provisioned and managed using application-specific
   mechanisms and management systems.  For instance, a firewall virtual
   appliance/VNF might be managed the same way as a physical firewall

3.  IoT vs. Edge Computing?

   The IOTOPS charter scopes its use of "IoT devices" to devices that

   *  are networked, either to the Internet or within limited
      administrative domains

   *  have a very limited end user interface or no end-user interface at

   *  are deployed in sufficiently large numbers that they cannot easily
      be managed or maintained manually

   The definitions of the various parts of Edge Computing by the Linux
   Foundation in [lfedge-wp] defines the constrained device edge and the
   smart device edge, which captures devices with different levels of
   flexibility, but they both fit into the above IOTOPS scope.  Thus for
   the purposes of this discussion we can use Edge Computing devices and
   IoT devices interchangeably.

   However, the devices at the constrained device edge are more likely
   to be single or fixed function in that they do not have the capacity
   or flexibility to perform other functions than envisioned prior to
   their deployment.  Such fixed function devices still require a
   software/firmware update capability as discussed in [RFC8240], but
   they do not require handling new application deployment and
   associated new communication patterns.

   The more flexible devices at the smart device edge are likely to be
   larger than the class 2 devices defined in [RFC7228], however if
   applications are sufficiently small, constrained devices might very
   well be edge computing devices.  But in general it makes sense to
   think about devices of the Raspberry Pi class and larger at the smart
   device edge.

   For such devices it is clear that the onboarding of the device (to
   the network and to some management system or controller) should be
   separable from the onboarding of some particular application (to its
   controller or management system).  Hence the separation between
   device onboarding and application (instance) onboarding seems
   required from an architectural perspective.

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4.  Network onboarding

   Network onboarding starts at L2 access and can take several different
   forms such as:

   *  Physical access to an Ethernet port

   *  Protocols like EAP-NOOB [I-D.ietf-emu-eap-noob], DPP [dpp], etc.

   In the world of laptop computers and smartphones such access might
   include traditional EAP but also additional steps such as Endpoint
   Assessment [RFC5209][RFC7632] before granting full access to the
   network.  Thus the onboarding to the network is not a new thing; what
   is new is applying it to IoT and Edge Computing devices with to user
   in front of the device as it is onboarded.

   As indicated above, if MUD [RFC8520] is used the network onboarding
   would logically include the retrieval and application of the usage

5.  Security Considerations

   This informational note discusses onboarding with the assumption that
   onboarding needs to address various security threats, but does not go
   into details.

   It seems like the roots of trust used for onboarding at the different
   levels relates closely to the design center for the different
   onboarding approaches.  Loosely we seem to have a few differently
   approaches (and this list is not exhaustive):

   *  Use Hardware manufacturer certificates.  This makes it possible to
      verify with the manufacturer that device is valid, but it does not
      indicate which management system or controller which a device
      should trust.

   *  Track the transfers of ownership through supply chain as done in
      FIDO [fidospec].  This enables secure late binding to a management
      system/controller since the signature chain from manufacturer to
      end user establishes trust in controller.

   *  Imprinting/configuring for/by the owner of the device.  This makes
      assumptions that either the future owner is known at the time of
      manufacturing or that there is some leap of faith involving a
      certificate (in e.g., text or bar code form) being registered in
      the controller by someone claiming to be the device owner.

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   The trust might also include initial measurement/attestation of
   firmware/software along the lines of RATS
   [I-D.ietf-rats-tpm-based-network-device-attest] to create a baseline
   before the device leaves the factory.

6.  Example: Project EVE

   Project EVE [eve] is an example of a secure but minimal approach to
   enable secure onboarding, without having a hard dependency on
   manufacturers and manufacturer certificates.

   *  When software is installed (factory or elsewhere):

      -  Imprint device which controller to trust (a root certificate)
         and initial URL to contact

      -  Generate a device certificate using the TPM

      -  Extract the device certificate and pass to final user (paper,
         bar code, etc)

      -  Perform initial measured boot to get baseline measurements
         along the lines of RATS TPM

   *  Then in any order

      -  User registers device certificate in controller

      -  Device is installed and powered on and connects to its

   At that point in time the EVE controller can specify which
   applications to deploy/boot/halt on device.

   Potentially EVE can also leverage [sdo], which is an open source
   implementation of the FIDO specification [fidospec], for the future
   cases where there is sufficient support in the supply chain for the
   FIDO signature chains.

7.  IANA Considerations

   There are no IANA actions needed for this document.

8.  Informative References

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   [RFC5209]  Sangster, P., Khosravi, H., Mani, M., Narayan, K., and J.
              Tardo, "Network Endpoint Assessment (NEA): Overview and
              Requirements", RFC 5209, DOI 10.17487/RFC5209, June 2008,

   [RFC7228]  Bormann, C., Ersue, M., and A. Keranen, "Terminology for
              Constrained-Node Networks", RFC 7228,
              DOI 10.17487/RFC7228, May 2014,

   [RFC7632]  Waltermire, D. and D. Harrington, "Endpoint Security
              Posture Assessment: Enterprise Use Cases", RFC 7632,
              DOI 10.17487/RFC7632, September 2015,

   [RFC8240]  Tschofenig, H. and S. Farrell, "Report from the Internet
              of Things Software Update (IoTSU) Workshop 2016",
              RFC 8240, DOI 10.17487/RFC8240, September 2017,

   [RFC8520]  Lear, E., Droms, R., and D. Romascanu, "Manufacturer Usage
              Description Specification", RFC 8520,
              DOI 10.17487/RFC8520, March 2019,

   [RFC8990]  Bormann, C., Carpenter, B., Ed., and B. Liu, Ed., "GeneRic
              Autonomic Signaling Protocol (GRASP)", RFC 8990,
              DOI 10.17487/RFC8990, May 2021,

   [RFC8994]  Eckert, T., Ed., Behringer, M., Ed., and S. Bjarnason, "An
              Autonomic Control Plane (ACP)", RFC 8994,
              DOI 10.17487/RFC8994, May 2021,

   [RFC8995]  Pritikin, M., Richardson, M., Eckert, T., Behringer, M.,
              and K. Watsen, "Bootstrapping Remote Secure Key
              Infrastructure (BRSKI)", RFC 8995, DOI 10.17487/RFC8995,
              May 2021, <https://www.rfc-editor.org/info/rfc8995>.

              Lear, E., "Deep Thoughts on Network Onboarding
              Challenges", Work in Progress, Internet-Draft, draft-lear-
              iotops-deep-thoughts-on-onboarding-00, 9 March 2021,

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              Sethi, M., Sarikaya, B., and D. Garcia-Carrillo, "Secure
              IoT Bootstrapping: A Survey", Work in Progress, Internet-
              Draft, draft-irtf-t2trg-secure-bootstrapping-00, 7 April
              2021, <https://datatracker.ietf.org/doc/html/draft-irtf-

              Aura, T., Sethi, M., and A. Peltonen, "Nimble out-of-band
              authentication for EAP (EAP-NOOB)", Work in Progress,
              Internet-Draft, draft-ietf-emu-eap-noob-05, 12 July 2021,

              Fedorkow, G., Voit, E., and J. Fitzgerald-McKay, "TPM-
              based Network Device Remote Integrity Verification", Work
              in Progress, Internet-Draft, draft-ietf-rats-tpm-based-
              network-device-attest-07, 10 June 2021,

   [dpp]      Wi-Fi Alliance, "Wi-Fi Device Provisioning Protocol
              (DPP)", Wi-Fi Alliance , 2018, <https://www.wi-

   [fidospec] FIDO Alliance, "FIDO Device Onboard Specification",
              December 2020, <https://fidoalliance.org/specs/FDO/FIDO-

   [oma]      Open Mobile Alliance, "Lightweight Machine to Machine
              Technical Specification: Core", Open Mobile Alliance ,
              June 2019,

              Linux Foundation, "Sharpening the Edge: Overview of the LF
              Edge Taxonomy and Framework", 2020,

   [eve]      Linux Foundation, "EVE is Edge Virtualization Engine",
              July 2021, <https://github.com/lf-edge/eve>.

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   [sdo]      Linux Foundation, "Secure Device OnBoard", July 2021,

Author's Address

   Erik Nordmark
   Santa Clara, CA,
   United States of America

   Email: nordmark@sonic.net

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