NETMOD Working Group Q. Wu
Internet-Draft Huawei
Intended status: Standards Track B. Lengyel
Expires: October 27, 2020 Ericsson Hungary
Y. Niu
Huawei
April 25, 2020

A YANG Data Model for Factory Default Settings
draft-ietf-netmod-factory-default-15

Abstract

This document defines a YANG data model with the "factory-reset" RPC to allow clients to reset a server back to its factory default condition. It also defines an optional "factory-default" datastore to allow clients to read the factory default configuration for the device.

The YANG data model in this document conforms to the Network Management Datastore Architecture (NMDA) defined in RFC 8342.

Status of This Memo

This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.

Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at https://datatracker.ietf.org/drafts/current/.

Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress."

This Internet-Draft will expire on October 27, 2020.

Copyright Notice

Copyright (c) 2020 IETF Trust and the persons identified as the document authors. All rights reserved.

This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.


Table of Contents

1. Introduction

This document defines a YANG data model and associated mechanism to reset a server to its factory default content. This mechanism may be used, e.g., when the existing configuration has major errors so re-starting the configuration process from scratch is the best option.

A "factory-reset" RPC is defined within the YANG data model. When resetting a device, all previous configuration settings will be lost and replaced by the factory default content.

In addition, an optional "factory-default" read-only datastore is defined within the YANG data model, that contains the data to replace the contents of implemented read-write conventional configuration datastores at reset. This datastore can also be used in the <get-data> operation.

The YANG data model in this document conforms to the Network Management Datastore Architecture defined in [RFC8342].

1.1. Terminology

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.

The following terms are defined in [RFC8342] [RFC7950] and are not redefined here:

The following terms are defined in this document as follows:

2. Factory-Reset RPC

A new "factory-reset" remote procedure call (RPC) is introduced. Upon receiving the RPC:

In addition, the "factory-reset" RPC MUST restore non-volatile storage to factory condition. Depending on the system, this may entail deleting dynamically generated files, such as those containing keys (e.g., /etc/ssl/private), certificates (e.g., /etc/ssl), logs (e.g., /var/log), and temporary files (e.g., /tmp/*). Any other cryptographic keys that are part of the factory-installed image will be retained (such as an IDevID certificate) [I-D.ietf-anima-bootstrapping-keyinfra]. When this process includes security-sensitive data such as cryptographic keys or passwords, it is RECOMMENDED to perform the deletion in a manner as thorough as possible (e.g., overwriting the physical storage medium with zeros and/or random bits for repurpose or end of life (EoL) disposal) to reduce the risk of the sensitive material being recoverable. The "factory-reset" RPC MAY also be used to trigger some other resetting tasks such as restarting the node or some of the software processes.

Note that operators should be aware that since all read-write datastores are immediately reset to factory default, the device may become unreachable as a host on the network. It is important to understand how a given vendor's device will behave after the RPC is executed. Implementors SHOULD reboot the device and get it properly configured or otherwise restart processes needed to bootstrap it.

3. Factory-Default Datastore

Following the guidelines for defining Datastores in the appendix A of [RFC8342], this document introduces a new optional datastore resource named "factory-default" that represents a pre-set initial configuration that can be used to initialize the configuration of a server. A device MAY implement the "factory-reset" RPC without implementing the "factory-default" datastore, which would only eliminate the ability to programmatically determine the factory default configuration.

The contents of <factory-default> are defined by the device vendor and MUST persist across device restarts. If supported, the factory-default datastore MUST be included in the list of datastores in YANG library [RFC 8525].

4. YANG Module

This module uses the "datastore" identity [RFC8342], and the "default-deny-all" extension statement from [RFC8341].

<CODE BEGINS> file "ietf-factory-default@2019-11-27.yang"
   module ietf-factory-default {
     yang-version 1.1;
     namespace "urn:ietf:params:xml:ns:yang:ietf-factory-default";
     prefix fd;

     import ietf-datastores {
       prefix ds;
       reference
         "RFC 8342: Network Management Datastore Architecture (NMDA)";
     }
     import ietf-netconf-acm {
       prefix nacm;
       reference
        "RFC8341: Network Configuration Access Control Model";
     }

     organization
       "IETF NETMOD (Network Modeling) Working Group";
     contact
       "WG Web:   <https://tools.ietf.org/wg/netconf/>
        WG List:  <mailto:netconf@ietf.org>

        Editor:   Qin Wu
                  <mailto:bill.wu@huawei.com>
        Editor:   Balazs Lengyel
                  <mailto:balazs.lengyel@ericsson.com>
        Editor:   Ye Niu
                  <mailto:niuye@huawei.com>";
     description
       "This module provides functionality to reset a server to its 
        factory default configuration and, when supported, to discover 
        the factory default configuration contents independent of 
        resetting the server.

        Copyright (c) 2020 IETF Trust and the persons identified as
        authors of the code.  All rights reserved.

        Redistribution and use in source and binary forms, with or
        without modification, is permitted pursuant to, and subject
        to the license terms contained in, the Simplified BSD License
        set forth in Section 4.c of the IETF Trust's Legal Provisions
        Relating to IETF Documents
        (http://trustee.ietf.org/license-info).

        This version of this YANG module is part of RFC XXXX;
        see the RFC itself for full legal notices.";
     // RFC Ed.: update the date below with the date of RFC publication
     // and remove this note.
     // RFC Ed.: replace XXXX with actual RFC number and remove this
     // note.
     revision 2019-11-27 {
       description
         "Initial revision.";
       reference
         "RFC XXXX: Factory default Setting";
     }

     feature factory-default-datastore {
       description
         "Indicates that the factory default configuration is
          available as a datastore.";
     }

     rpc factory-reset {
       nacm:default-deny-all;
       description
         "The server resets all datastores to their factory 
         default content and any non-volatile storage back to 
         factory condition, deleting all dynamically generated 
         files, including those containing keys, certificates, 
         logs, and other temporary files.

         Depending on the factory default configuration, after 
         being reset, the device may become unreachable on the 
         network.";
     }

     identity factory-default {
       if-feature "factory-default-datastore";
       base ds:datastore;
       description
         "This read-only datastore contains the factory default 
         configuration for the device that will be used to replace 
         the contents of the read-write conventional configuration 
         datastores during a 'factory-reset' RPC operation.";
     }
   }
<CODE ENDS>

5. IANA Considerations

This document registers one URI in the IETF XML Registry [RFC3688]. The following registration has been made:

  URI: urn:ietf:params:xml:ns:yang:ietf-factory-default
  Registrant Contact: The IESG.
  XML: N/A, the requested URI is an XML namespace.

This document registers one YANG module in the YANG Module Names Registry [RFC6020]. The following registration has been made:

  name: ietf-factory-default
  namespace: urn:ietf:params:xml:ns:yang:ietf-factory-default
  prefix: fd
  RFC: xxxx

6. Security Considerations

The YANG module defined in this document extends the base operations for NETCONF [RFC6241] and RESTCONF [RFC8040]. The lowest NETCONF layer is the secure transport layer, and the mandatory-to-implement secure transport is Secure Shell (SSH) [RFC6242]. The lowest RESTCONF layer is HTTPS, and the mandatory-to-implement secure transport is TLS [RFC8446].

Access to the "factory-reset" RPC operation and factory default values of all configuration data nodes within "factory-default" datastore is considered sensitive and therefore has been restricted using the "default-deny-all" access control defined in [RFC8341].

The "factory-reset" RPC can prevent any further management of the device when the server is reset back to its factory default condition,e.g., the session and client config are included in the factory default contents or treated as dynamic files on the nonvoliatile storage and overwritten by the the "factory-reset" RPC.

The operational disruption caused by setting the config to factory default contents or lacking appropriate security control on factory default configuration varies greatly depending on the implementation and current config.

The non-volatile storage is expected to be wiped clean and reset back to the factory default state, but there is no guarantee that the data is wiped according to any particular data cleansing standard, and the owner of the device MUST NOT rely on any sensitive data (e.g., private keys) being forensically unrecoverable from the device's non-volatile storage after a factory-reset RPC has been invoked.

7. Acknowledgements

Thanks to Juergen Schoenwaelder, Ladislav Lhotka, Alex Campbell, Joe Clarke, Robert Wilton, Kent Watsen, Joel Jaeggli, Lou Berger, Andy Bierman, Susan Hares, Benjamin Kaduk, Stephen Kent, Stewart Bryant, Éric Vyncke, Murray Kucherawy, Roman Danyliw, Tony Przygienda, John Heasley for reviewing this draft and providing important input to this document.

8. Contributors

   Rohit R Ranade
   Huawei 
   Email: rohitrranade@huawei.com

9. References

9.1. Normative References

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, January 2004.
[RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, DOI 10.17487/RFC6020, October 2010.
[RFC7950] Bjorklund, M., "The YANG 1.1 Data Modeling Language", RFC 7950, DOI 10.17487/RFC7950, August 2016.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017.
[RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration Access Control Model", STD 91, RFC 8341, DOI 10.17487/RFC8341, March 2018.
[RFC8342] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K. and R. Wilton, "Network Management Datastore Architecture (NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018.
[RFC8525] Bierman, A., Bjorklund, M., Schoenwaelder, J., Watsen, K. and R. Wilton, "YANG Library", RFC 8525, DOI 10.17487/RFC8525, March 2019.

9.2. Informative References

[I-D.ietf-anima-bootstrapping-keyinfra] Pritikin, M., Richardson, M., Eckert, T., Behringer, M. and K. Watsen, "Bootstrapping Remote Secure Key Infrastructures (BRSKI)", Internet-Draft draft-ietf-anima-bootstrapping-keyinfra-41, April 2020.
[RFC6241] Enns, R., Bjorklund, M., Schoenwaelder, J. and A. Bierman, "Network Configuration Protocol (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011.
[RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011.
[RFC8040] Bierman, A., Bjorklund, M. and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017.
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018.

Appendix A. Changes between revisions

Editorial Note (To be removed by RFC Editor)

v14 -15

v13 - 14

v12 - 13

v11 - 12

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Authors' Addresses

Qin Wu Huawei 101 Software Avenue, Yuhua District Nanjing, Jiangsu 210012 China EMail: bill.wu@huawei.com
Balazs Lengyel Ericsson Hungary Magyar Tudosok korutja 11 1117 Budapest, Hungary Phone: +36-70-330-7909 EMail: balazs.lengyel@ericsson.com
Ye Niu Huawei EMail: niuye@huawei.com