A YANG Data Model
for Factory Default Settings
Huawei
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bill.wu@huawei.com
Ericsson Hungary
Magyar Tudosok korutja 11
Budapest1117
Hungary
+36-70-330-7909
balazs.lengyel@ericsson.com
Huawei
niuye@huawei.com
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.
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&nbhy;data> operation.
The YANG data model in this document conforms to the Network
Management Datastore Architecture defined in .
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
when, and only
when, they appear in all capitals, as shown here.
The following terms are defined in and 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>".
"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 ). 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.
"Factory-Default" Datastore
Following the guidelines for defining datastores in
, 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 .
YANG Module
This module uses the "datastore" identity and the
"default&nbhy;deny-all" extension statement from .
WG List:
Editor: Qin Wu
Editor: Balazs Lengyel
Editor: Ye Niu
";
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.";
}
}]]>
IANA Considerations
IANA has registered the following URI in the "ns" subregistry within
the "IETF XML Registry" :
- 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 within the
"YANG Parameters" registry:
- Name:
- ietf-factory-default
- Namespace:
- urn:ietf:params:xml:ns:yang:ietf-factory-default
- Prefix:
- fd
- Reference:
- 8808
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 or RESTCONF .
The lowest NETCONF layer is the secure transport layer, and the
mandatory-to-implement secure transport is Secure Shell (SSH)
. The lowest RESTCONF layer is HTTPS, and the
mandatory-to-implement secure transport is TLS .
The Network Configuration Access Control Model (NACM)
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 .
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.
References
Normative References
Informative References
Acknowledgements
Thanks to ,
, , , , ,
, , , , ,
, , , , , , and for reviewing, and providing
important input to, this document.
Contributors
Huawei
rohitrranade@huawei.com