rfc:rfc8808
Internet Engineering Task Force (IETF) Q. Wu Request for Comments: 8808 Huawei Category: Standards Track B. Lengyel ISSN: 2070-1721 Ericsson Hungary
Y. Niu
Huawei
August 2020
A YANG Data Model for Factory Default Settings
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 is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 7841.
Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at https://www.rfc-editor.org/info/rfc8808.
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 1.1. Terminology 2. "Factory-Reset" RPC 3. "Factory-Default" Datastore 4. YANG Module 5. IANA Considerations 6. Security Considerations 7. References 7.1. Normative References 7.2. Informative References Acknowledgements Contributors Authors' Addresses
1. Introduction
This document defines a YANG data model and associated mechanism to reset a server to its factory default contents. This mechanism may be used, for example, when the existing configuration has major errors and so restarting the configuration process from scratch is the best option.
A "factory-reset" remote procedure call (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 contents.
In addition, an optional "factory-default" read-only datastore is defined within the YANG data model. This datastore contains the data to replace the contents of implemented read-write conventional configuration datastores at reset and 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] and [RFC7950] and are not redefined here:
- server
- startup configuration datastore
- candidate configuration datastore
- running configuration datastore
- intended configuration datastore
- operational state datastore
- conventional configuration datastore
- datastore schema
- RPC operation
This document defines the following term:
"factory-default" datastore: A read-only configuration datastore
holding a preset initial configuration that is used to initialize
the configuration of a server. This datastore is referred to as
"<factory-default>".
2. "Factory-Reset" RPC
This document introduces a new "factory-reset" RPC. Upon receiving the RPC:
- All supported conventional read-write configuration datastores
(i.e., <running>, <startup>, and <candidate>) are reset to the
contents of <factory-default>.
- Read-only datastores receive their contents from other datastores
(e.g., <intended> gets its contents from <running>).
- All data in any dynamic configuration datastores MUST be
discarded.
- The contents of the <operational> datastore MUST reflect the
operational state of the device after applying the factory default
configuration.
In addition, the "factory-reset" RPC MUST restore nonvolatile 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 Initial Device Identifier (IDevID)
certificate [BRSKI]). When this process includes security-sensitive
data such as cryptographic keys or passwords, it is RECOMMENDED to
perform the deletion in as thorough a manner as possible (e.g.,
overwriting the physical storage medium with zeros and/or random bits
for repurposing 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 Appendix A of [RFC8342], this document introduces a new optional datastore resource named "factory-default" that represents a preset 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.
Name: "factory-default".
YANG modules: The "factory-default" datastore schema MUST be either
(1) the same as the conventional configuration datastores or
(2) a subset of the datastore schema for the conventional
configuration datastores.
YANG nodes: All "config true" data nodes.
Management operations: The contents of the datastore is set by the
server in an implementation-dependent manner. The contents cannot
be changed by management operations via the Network Configuration
Protocol (NETCONF), RESTCONF, the CLI, etc., unless specialized,
dedicated operations are provided. The datastore can be read
using the standard NETCONF/RESTCONF protocol operations. The
"factory-reset" operation copies the factory default contents to
<running> and, if present, <startup> and/or <candidate>. The
contents of these datastores is then propagated automatically to
any other read-only datastores, e.g., <intended> and
<operational>.
Origin: This document does not define a new origin identity, as it
does not interact with the <operational> datastore.
Protocols: RESTCONF, NETCONF, and other management protocols.
Defining YANG module: "ietf-factory-default".
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 the YANG library [RFC8525].
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@2020-08-31.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
"RFC 8341: Network Configuration Access Control Model";
}
organization
"IETF Network Modeling (netmod) Working Group";
contact
"WG Web: <https://datatracker.ietf.org/wg/netmod/>
WG List: <mailto:netmod@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
independently 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
(https://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC 8808; see the
RFC itself for full legal notices.";
revision 2020-08-31 {
description
"Initial revision.";
reference
"RFC 8808: A YANG Data Model for Factory Default Settings";
}
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 contents and any nonvolatile 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
IANA has registered the following URI in the "ns" subregistry within the "IETF XML Registry" [RFC3688]:
URI: urn:ietf:params:xml:ns:yang:ietf-factory-default Registrant Contact: The IESG. XML: N/A; the requested URI is an XML namespace.
IANA has registered the following YANG module in the "YANG Module Names" subregistry [RFC6020] within the "YANG Parameters" registry:
Name: ietf-factory-default Namespace: urn:ietf:params:xml:ns:yang:ietf-factory-default Prefix: fd Reference: 8808
6. Security Considerations
The YANG module specified in this document defines a schema for data that is designed to be accessed via network management protocols such as NETCONF [RFC6241] or 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].
The Network Configuration Access Control Model (NACM) [RFC8341] provides the means to restrict access for particular NETCONF or RESTCONF users to a preconfigured subset of all available NETCONF or RESTCONF protocol operations and content.
Access to the "factory-reset" RPC operation and factory default values of all configuration data nodes within the "factory-default" datastore is considered sensitive and therefore has been restricted by using the "default-deny-all" access control statement 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 configurations are included in the factory default contents or treated as dynamic files in nonvolatile storage and overwritten by the "factory-reset" RPC.
The operational disruption caused by setting the configuration to factory default contents or the lack of appropriate security control on the factory default configuration varies greatly, depending on the implementation and current configuration.
The nonvolatile 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 clean 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 nonvolatile storage after a "factory-reset" RPC has been
invoked.
7. References
7.1. 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,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004,
<https://www.rfc-editor.org/info/rfc3688>.
[RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for
the Network Configuration Protocol (NETCONF)", RFC 6020,
DOI 10.17487/RFC6020, October 2010,
<https://www.rfc-editor.org/info/rfc6020>.
[RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
and A. Bierman, Ed., "Network Configuration Protocol
(NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
<https://www.rfc-editor.org/info/rfc6241>.
[RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure
Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011,
<https://www.rfc-editor.org/info/rfc6242>.
[RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
RFC 7950, DOI 10.17487/RFC7950, August 2016,
<https://www.rfc-editor.org/info/rfc7950>.
[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
<https://www.rfc-editor.org/info/rfc8040>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration
Access Control Model", STD 91, RFC 8341,
DOI 10.17487/RFC8341, March 2018,
<https://www.rfc-editor.org/info/rfc8341>.
[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,
<https://www.rfc-editor.org/info/rfc8342>.
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>.
[RFC8525] Bierman, A., Bjorklund, M., Schoenwaelder, J., Watsen, K.,
and R. Wilton, "YANG Library", RFC 8525,
DOI 10.17487/RFC8525, March 2019,
<https://www.rfc-editor.org/info/rfc8525>.
7.2. Informative References
[BRSKI] Pritikin, M., Richardson, M. C., Eckert, T., Behringer, M.
H., and K. Watsen, "Bootstrapping Remote Secure Key
Infrastructures (BRSKI)", Work in Progress, Internet-
Draft, draft-ietf-anima-bootstrapping-keyinfra-43, 7
August 2020, <https://tools.ietf.org/html/draft-ietf-
anima-bootstrapping-keyinfra-43>.
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, and John Heasley for reviewing, and providing important input to, this document.
Contributors
Rohit R Ranade Huawei
Email: rohitrranade@huawei.com
Authors' Addresses
Qin Wu Huawei Yuhua District 101 Software Avenue Nanjing Jiangsu, 210012 China
Email: bill.wu@huawei.com
Balazs Lengyel Ericsson Hungary Budapest Magyar Tudosok korutja 11 1117 Hungary
Phone: +36-70-330-7909 Email: balazs.lengyel@ericsson.com
Ye Niu Huawei
Email: niuye@huawei.com
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