| Network Working Group | A. Bierman |
| Internet-Draft | YumaWorks |
| Intended status: Standards Track | M. Bjorklund |
| Expires: October 24, 2013 | Tail-f Systems |
| April 22, 2013 |
YANG Data Model for System Management
draft-ietf-netmod-system-mgmt-06
This document defines a YANG data model for the configuration and identification of the management system of a device.
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 http://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 24, 2013.
Copyright (c) 2013 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 (http://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.
This document defines a YANG [RFC6020] data model for the configuration and identification of some common properties within the management system of a device.
Devices that are managed by NETCONF and perhaps other mechanisms have common properties that need to be configured and monitored in a standard way.
The "ietf‑system" YANG module defined in this document provides the following features:
The keywords "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].
The following terms are used within this document:
A simplified graphical representation of the data model is used in this document. The meaning of the symbols in these diagrams is as follows:
There are many common properties used to identify devices, operating systems, software versions, etc. that need to be supported in the system data module. These objects are defined as operational data and the information returned by the server is intended to be specific to the device vendor.
Some user-configurable administrative strings are also provided, such as the system location and description.
The management of the date and time used by the system need to be supported. Use of one or more NTP servers to automatically set the system date and time need to be possible. Utilization of the Timezone database [RFC6557] also need to be supported. It should be possible for the server, as well as clients, to configure the system to use NTP.
The authentication mechanism need to support password authentication over RADIUS, to support deployment scenarios with centralized authentication servers. Additionally, local users need to be supported, for scenarios when no centralized authentication server exists, or for situations where the centralized authentication server cannot be reached from the device.
Since the mandatory transport protocol for NETCONF is SSH [RFC6242] the authentication model need to support SSH's "publickey" and "password" authentication methods [RFC4252].
The model for authentication configuration should be flexible enough to support authentication methods defined by other standard documents or by vendors. It should be possible for the server, as well as clients, to configure the system authentication properties.
The data model for system identification has the following structure:
+--rw system
+--rw contact? string
+--rw hostname? inet:domain-name
+--rw location? string
+--ro platform
+--ro os-name? string
+--ro os-release? string
+--ro os-version? string
+--ro machine? string
The data model for system time management has the following structure:
+--rw system
+--rw clock
| +--ro current-datetime? yang:date-and-time
| +--ro boot-datetime? yang:date-and-time
| +--rw (timezone)?
| +--:(timezone-location)
| | +--rw timezone-location? string
| +--:(timezone-utc-offset)
| +--rw timezone-utc-offset? int16
+--rw ntp
+--rw enabled? boolean
+--rw server [address]
+--rw association-type? enumeration
+--rw address inet:host
+--rw enabled? boolean
+--rw iburst? boolean
+--rw prefer? boolean
The data model for configuration of the DNS resolver has the following structure:
+--rw system
+--rw dns
+--rw search* inet:domain-name
+--rw server* inet:ip-address
+--rw options
+--rw timeout? uint8
+--rw attempts? uint8
The data model for configuration of the RADIUS client has the following structure:
+--rw system
+--rw radius
+--rw server [address]
| +--rw address inet:host
| +--rw (transport)
| | +--:(udp)
| | +--rw udp
| | +--rw authentication-port? inet:port-number
| | +--rw shared-secret string
| +--rw authentication-type? identityref
+--rw options
+--rw timeout? uint8
+--rw attempts? uint8
This document defines three authentication methods for use with NETCONF:
Additional methods can be defined by other standard documents or by vendors.
This document defines two optional YANG features, "local‑users" and "radius‑authentication", which the server advertises to indicate support for configuring local users on the device, and support for using RADIUS for authentication, respectively.
The authentication parameters defined in this document are primarily used to configure authentication of NETCONF users, but MAY also be used by other interfaces, e.g., a Command Line Interface or a Web-based User Interface.
The data model for user authentication has the following structure:
+--rw system
+--rw authentication
+--rw user-authentication-order* identityref
+--rw user [name]
+--rw name string
+--rw password? crypt-hash
+--rw ssh-key [name]
+--rw name string
+--rw algorithm? string
+--rw key-data? binary
If the NETCONF server advertises the "local‑users" feature, configuration of local users and their SSH public keys is supported in the /system/authentication/user list.
Public key authentication is requested by the SSH client. If the "local‑users" feature is supported, then when a NETCONF client starts an SSH session towards the server using the "publickey" authentication "method name" [RFC4252], the SSH server looks up the user name given in the SSH authentication request in the /system/authentication/user list, and verifies the key as described in [RFC4253].
If the NETCONF server advertises the "local‑users" feature, configuration of local users and their passwords is supported in the /system/authentication/user list.
For NETCONF transport protocols that support password authentication, the leaf-list "user‑authentication‑order" is used to control if local user password authentication should be used.
In SSH, password authentication is requested by the client. Other NETCONF transport protocols MAY also support password authentication.
When local user password authentication is requested, the NETCONF transport looks up the user name provided by the client in the /system/ authentication/user list, and verifies the password.
If the NETCONF server advertises the "radius‑authentication" feature, the device supports user authentication using RADIUS.
For NETCONF transport protocols that support password authentication, the leaf-list "user‑authentication‑order" is used to control if RADIUS password authentication should be used.
In SSH, password authentication is requested by the client. Other NETCONF transport protocols MAY also support password authentication.
Two protocol operations are included to restart or shutdown the system. The 'system‑restart' operation can be used to restart the entire system (not just the NETCONF server). The 'system‑shutdown' operation can be used to power off the entire system.
This YANG module imports YANG extensions from [RFC6536], and imports YANG types from [I-D.ietf-netmod-rfc6021-bis] and [I-D.ietf-netmod-iana-timezones]. It also references [RFC1321], [RFC2865], [RFC3418], [RFC5607], [IEEE-1003.1-2008], and [FIPS.180-3.2008].
RFC Ed.: update the date below with the date of RFC publication and remove this note.
<CODE BEGINS> file "ietf-system@2013-04-21.yang"
module ietf-system {
namespace "urn:ietf:params:xml:ns:yang:ietf-system";
prefix "sys";
import ietf-yang-types {
prefix yang;
}
import ietf-inet-types {
prefix inet;
}
import ietf-netconf-acm {
prefix nacm;
}
import iana-timezones {
prefix ianatz;
}
organization
"IETF NETMOD (NETCONF Data Modeling Language) Working Group";
contact
"WG Web: <http://tools.ietf.org/wg/netmod/>
WG List: <mailto:netmod@ietf.org>
WG Chair: David Kessens
<mailto:david.kessens@nsn.com>
WG Chair: Juergen Schoenwaelder
<mailto:j.schoenwaelder@jacobs-university.de>
Editor: Andy Bierman
<mailto:andy@yumaworks.com>
Editor: Martin Bjorklund
<mailto:mbj@tail-f.com>";
description
"This module contains a collection of YANG definitions for the
configuration and identification of the management system of a
device.
Copyright (c) 2013 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.: replace XXXX with actual RFC number and remove this
// note.
// RFC Ed.: remove this note
// Note: extracted from draft-ietf-netmod-system-mgmt-06.txt
// RFC Ed.: update the date below with the date of RFC publication
// and remove this note.
revision "2013-04-21" {
description
"Initial revision.";
reference
"RFC XXXX: A YANG Data Model for System Management";
}
/*
* Typedefs
*/
typedef crypt-hash {
type string {
pattern
'$0$.*'
+ '|$1$[a-zA-Z0-9./]{1,8}$[a-zA-Z0-9./]{22}'
+ '|$5$(rounds=\d+$)?[a-zA-Z0-9./]{1,16}$[a-zA-Z0-9./]{43}'
+ '|$6$(rounds=\d+$)?[a-zA-Z0-9./]{1,16}$[a-zA-Z0-9./]{86}';
}
description
"The crypt-hash type is used to store passwords using
a hash function. The algorithms for applying the hash
function and encoding the result are implemented in
various UNIX systems as the function crypt(3).
A value of this type matches one of the forms:
$0$<clear text password>
$<id>$<salt>$<password hash>
$<id>$<parameter>$<salt>$<password hash>
The '$0$' prefix signals that the value is clear text. When
such a value is received by the server, a hash value is
calculated, and the string '$<id>$<salt>$' or
$<id>$<parameter>$<salt>$ is prepended to the result. This
value is stored in the configuration data store.
If a value starting with '$<id>$', where <id> is not '0', is
received, the server knows that the value already represents a
hashed value, and stores it as is in the data store.
When a server needs to verify a password given by a user, it
finds the stored password hash string for that user, extracts
the salt, and calculates the hash with the salt and given
password as input. If the calculated hash value is the same
as the stored value, the password given by the client is
correct.
This type defines the following hash functions:
id | hash function | feature
---+---------------+-------------------
1 | MD5 | crypt-hash-md5
5 | SHA-256 | crypt-hash-sha-256
6 | SHA-512 | crypt-hash-sha-512
The server indicates support for the different hash functions
by advertising the corresponding feature.";
reference
"IEEE Std 1003.1-2008 - crypt() function
Wikipedia: http://en.wikipedia.org/wiki/Crypt_(C)
RFC 1321: The MD5 Message-Digest Algorithm
FIPS.180-3.2008: Secure Hash Standard";
}
/*
* Features
*/
feature radius {
description
"Indicates that the device can be configured as a RADIUS
client.";
reference
"RFC 2865: Remote Authentication Dial In User Service "
+ "(RADIUS)";
}
feature authentication {
description
"Indicates that the device can be configured
to do authentication of users.";
}
feature local-users {
if-feature authentication;
description
"Indicates that the device supports
local user authentication.";
}
feature radius-authentication {
if-feature radius;
if-feature authentication;
description
"Indicates that the device supports user authentication over
RADIUS.";
reference
"RFC 2865: Remote Authentication Dial In User Service (RADIUS)
RFC 5607: Remote Authentication Dial-In User Service (RADIUS)
Authorization for Network Access Server (NAS)
Management";
}
feature crypt-hash-md5 {
description
"Indicates that the device supports the MD5
hash function in 'crypt-hash' values";
reference "RFC 1321: The MD5 Message-Digest Algorithm";
}
feature crypt-hash-sha-256 {
description
"Indicates that the device supports the SHA-256
hash function in 'crypt-hash' values";
reference "FIPS.180-3.2008: Secure Hash Standard";
}
feature crypt-hash-sha-512 {
description
"Indicates that the device supports the SHA-512
hash function in 'crypt-hash' values";
reference "FIPS.180-3.2008: Secure Hash Standard";
}
feature ntp {
description
"Indicates that the device can be configured
to use one or more NTP servers to set the
system date and time.";
}
feature timezone-location {
description
"Indicates that the local timezone on the device
can be configured to use the TZ database
to set the timezone and manage daylight savings time.";
reference
"TZ Database http://www.twinsun.com/tz/tz-link.htm
Maintaining the Timezone Database
RFC 6557 (BCP 175)";
}
/*
* Identities
*/
identity authentication-method {
description
"Base identity for user authentication methods.";
}
identity radius {
base authentication-method;
description
"Indicates user authentication using RADIUS.";
reference
"RFC 2865: Remote Authentication Dial In User Service (RADIUS)
RFC 5607: Remote Authentication Dial-In User Service (RADIUS)
Authorization for Network Access Server (NAS)
Management";
}
identity local-users {
base authentication-method;
description
"Indicates password-based authentication of locally
configured users.";
}
identity radius-authentication-type {
description
"Base identity for RADIUS authentication types.";
}
identity radius-pap {
base radius-authentication-type;
description
"The device requests PAP authentication from the RADIUS
server.";
reference
"RFC 2865: Remote Authentication Dial In User Service";
}
identity radius-chap {
base radius-authentication-type;
description
"The device requests CHAP authentication from the RADIUS
server.";
reference
"RFC 2865: Remote Authentication Dial In User Service";
}
/*
* Top-level container
*/
container system {
description
"System group configuration.";
leaf contact {
type string {
length "0..255";
}
description
"The administrator contact information for the system.";
reference
"RFC 3418 - Management Information Base (MIB) for the
Simple Network Management Protocol (SNMP)
SNMPv2-MIB.sysContact";
}
leaf hostname {
type inet:domain-name;
description
"The name of the host. This name can be a single domain
label, or the fully qualified domain name of the host.";
}
leaf location {
type string {
length "0..255";
}
description
"The system location.";
reference
"RFC 3418 - Management Information Base (MIB) for the
Simple Network Management Protocol (SNMP)
SNMPv2-MIB.sysLocation";
}
container platform {
config false;
description
"Contains vendor-specific information for
identifying the system platform and operating system.";
reference
"IEEE Std 1003.1-2008 - sys/utsname.h";
leaf os-name {
type string;
description
"The name of the operating system in use,
for example 'Linux'";
reference
"IEEE Std 1003.1-2008 - utsname.sysname";
}
leaf os-release {
type string;
description
"The current release level of the operating
system in use. This string MAY indicate
the OS source code revision.";
reference
"IEEE Std 1003.1-2008 - utsname.release";
}
leaf os-version {
type string;
description
"The current version level of the operating
system in use. This string MAY indicate
the specific OS build date and target variant
information.";
reference
"IEEE Std 1003.1-2008 - utsname.version";
}
leaf machine {
type string;
description
"A vendor-specific identifier string representing
the hardware in use.";
reference
"IEEE Std 1003.1-2008 - utsname.machine";
}
}
container clock {
description
"Configuration and monitoring of the system
date and time properties.";
leaf current-datetime {
type yang:date-and-time;
config false;
description
"The current system date and time.";
}
leaf boot-datetime {
type yang:date-and-time;
config false;
description
"The system date and time when the NETCONF
server last restarted.";
}
choice timezone {
description
"The system timezone information.";
leaf timezone-location {
if-feature timezone-location;
type ianatz:iana-timezone;
description
"The TZ database location identifier string
to use for the system, such as 'Europe/Stockholm'.";
}
leaf timezone-utc-offset {
type int16 {
range "-1500 .. 1500";
}
units "minutes";
description
"The number of minutes to add to UTC time to
identify the timezone for this system.
For example, 'UTC - 8:00 hours' would be
represented as '-480'. Note that automatic
daylight savings time adjustment is not provided,
if this object is used.";
}
}
}
container ntp {
if-feature ntp;
description
"Configuration of the NTP client.";
leaf enabled {
type boolean;
default true;
description
"Indicates that the system should attempt
to synchronize the system clock with an
NTP server from the 'ntp/server' list.";
}
list server {
key address;
description
"List of NTP servers to use for
system clock synchronization. If '/system/ntp/enabled'
is 'true', then the system will attempt to
contact and utilize the specified NTP servers.";
leaf association-type {
type enumeration {
enum server {
description
"Use client association mode. This device
will not provide synchronization to the
configured NTP server.";
}
enum peer {
description
"Use symmetric active association mode.
This device may provide synchronization
to the configured NTP server.";
}
enum pool {
description
"Use client association mode with one or
more of the NTP servers found by DNS
resolution of the domain name given by
the 'address' leaf. This device will not
provide synchronization to the servers.";
}
}
default server;
description
"The desired association type for this NTP server.";
}
leaf address {
type inet:host;
description
"The IP address or domain name of the NTP server.";
}
leaf enabled {
type boolean;
default true;
description
"Indicates whether this server is enabled for use or
not.";
}
leaf iburst {
type boolean;
default false;
description
"Indicates whether this server should enable burst
synchronization or not.";
}
leaf prefer {
type boolean;
default false;
description
"Indicates whether this server should be preferred
or not.";
}
}
}
container dns {
description
"Configuration of the DNS resolver.";
leaf-list search {
type inet:domain-name;
ordered-by user;
description
"An ordered list of domains to search when resolving
a host name.";
}
leaf-list server {
type inet:ip-address;
ordered-by user;
description
"Addresses of the name servers that the resolver should
query.
Implementations MAY limit the number of entries in this
leaf list.";
}
container options {
description
"Resolver options. The set of available options has been
limited to those that are generally available across
different resolver implementations, and generally
useful.";
leaf timeout {
type uint8 {
range "1..max";
}
units "seconds";
default "5";
description
"The amount of time the resolver will wait for a
response from a remote name server before
retrying the query via a different name server.";
}
leaf attempts {
type uint8 {
range "1..max";
}
default "2";
description
"The number of times the resolver will send a query to
its name servers before giving up and returning an
error to the calling application.";
}
}
}
container radius {
if-feature radius;
description
"Configuration of the RADIUS client.";
list server {
key address;
ordered-by user;
description
"List of RADIUS servers used by the device.";
leaf address {
type inet:host;
description
"The address of the RADIUS server.";
}
choice transport {
mandatory true;
description
"The transport protocol specific parameters
for this server. It is expected that new
case statements will be added over time to
support other transport protocols.";
case udp {
container udp {
description
"Contains UDP specific configuration parameters
for RADIUS.";
leaf authentication-port {
type inet:port-number;
default "1812";
description
"The port number of the RADIUS server.";
}
leaf shared-secret {
type string;
mandatory true;
nacm:default-deny-all;
description
"The shared secret which is known to both the
RADIUS client and server.";
reference
"RFC 2865: Remote Authentication Dial In User
Service";
}
}
}
}
leaf authentication-type {
type identityref {
base radius-authentication-type;
}
default radius-pap;
description
"The authentication type requested from the RADIUS
server.";
}
}
container options {
description
"RADIUS client options.";
leaf timeout {
type uint8 {
range "1..max";
}
units "seconds";
default "5";
description
"The number of seconds the device will wait for a
response from a RADIUS server before trying with a
different server.";
}
leaf attempts {
type uint8 {
range "1..max";
}
default "2";
description
"The number of times the device will send a query to
the RADIUS servers before giving up.";
}
}
}
container authentication {
nacm:default-deny-write;
if-feature authentication;
description
"The authentication configuration subtree.";
leaf-list user-authentication-order {
type identityref {
base authentication-method;
}
must '(. != "sys:radius" or ../../radius/server)' {
error-message
"When 'radius' is used, a RADIUS server"
+ " must be configured.";
description
"When 'radius' is used as an authentication method,
a RADIUS server must be configured.";
}
ordered-by user;
description
"When the device authenticates a user with
a password, it tries the authentication methods in this
leaf-list in order. If authentication with one method
fails, the next method is used. If no method succeeds,
the user is denied access.
If the 'radius-authentication' feature is advertised by
the NETCONF server, the 'radius' identity can be added to
this list.
If the 'local-users' feature is advertised by the
NETCONF server, the 'local-users' identity can be
added to this list.";
}
list user {
if-feature local-users;
key name;
description
"The list of local users configured on this device.";
leaf name {
type string;
description
"The user name string identifying this entry.";
}
leaf password {
type crypt-hash;
description
"The password for this entry.";
}
list ssh-key {
key name;
description
"A list of public SSH keys for this user.";
reference
"RFC 4253: The Secure Shell (SSH) Transport Layer
Protocol";
leaf name {
type string;
description
"An arbitrary name for the ssh key.";
}
leaf algorithm {
type string;
description
"The public key algorithm name for this ssh key.
Valid values are the values in the IANA Secure Shell
(SSH) Protocol Parameters registry, Public Key
Algorithm Names";
reference
"IANA Secure Shell (SSH) Protocol Parameters registry,
Public Key Algorithm Names";
}
leaf key-data {
type binary;
description
"The binary key data for this ssh key.";
}
}
}
}
}
rpc set-current-datetime {
nacm:default-deny-all;
description
"Set the /system/clock/current-datetime leaf
to the specified value.
If the system is using NTP (i.e., /system/ntp/enabled
is set to 'true'), then this operation will
fail with error-tag 'operation-failed',
and error-app-tag value of 'ntp-active'";
input {
leaf current-datetime {
type yang:date-and-time;
mandatory true;
description
"The current system date and time.";
}
}
}
rpc system-restart {
nacm:default-deny-all;
description
"Request that the entire system be restarted immediately.
A server SHOULD send an rpc reply to the client before
restarting the system.";
}
rpc system-shutdown {
nacm:default-deny-all;
description
"Request that the entire system be shut down immediately.
A server SHOULD send an rpc reply to the client before
shutting down the system.";
}
}
<CODE ENDS>
This document registers one URI in the IETF XML registry [RFC3688]. Following the format in RFC 3688, the following registration is requested to be made.
URI: urn:ietf:params:xml:ns:yang:ietf-system
Registrant Contact: The NETMOD WG of the IETF.
XML: N/A, the requested URI is an XML namespace.
This document registers one YANG module in the YANG Module Names registry [RFC6020].
name: ietf-system namespace: urn:ietf:params:xml:ns:yang:ietf-system prefix: sys reference: RFC XXXX
The YANG module defined in this memo is designed to be accessed via the NETCONF protocol [RFC6241]. The lowest NETCONF layer is the secure transport layer and the mandatory-to-implement secure transport is SSH [RFC6242].
There are a number of data nodes defined in this YANG module which are writable/creatable/deletable (i.e., config true, which is the default). These data nodes may be considered sensitive or vulnerable in some network environments. Write operations (e.g., edit-config) to these data nodes without proper protection can have a negative effect on network operations. These are the subtrees and data nodes and their sensitivity/vulnerability:
Some of the readable data nodes in this YANG module may be considered sensitive or vulnerable in some network environments. It is thus important to control read access (e.g., via get, get-config, or notification) to these data nodes. These are the subtrees and data nodes and their sensitivity/vulnerability:
Some of the RPC operations in this YANG module may be considered sensitive or vulnerable in some network environments. It is thus important to control access to these operations. These are the operations and their sensitivity/vulnerability:
-- RFC Ed.: remove this section before publication.