| Network Working Group | A. Bierman |
| Internet-Draft | Brocade |
| Intended status: Standards Track | M. Bjorklund |
| Expires: May 03, 2012 | Tail-f Systems |
| October 31, 2011 |
YANG Data Model for System Management
draft-bierman-netmod-system-mgmt-01
Abstract
This document defines a YANG data model for the configuration and identification of the management system of a device.
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 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 May 03, 2012.
Copyright Notice
Copyright (c) 2011 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.
Table of Contents
- 1. Introduction
- 1.1. Terminology
- 1.1.1. Terms
- 2. Objectives
- 2.1. System Identification
- 2.2. System Time Management
- 2.3. User Authentication
- 3. System Data Model
- 3.1. System Identification
- 3.2. System Time Management
- 3.3. DNS Resolver Model
- 3.4. User Authentication Model
- 3.4.1. SSH Public Key Authentication
- 3.4.2. Local User Password Authentication
- 3.4.3. RADIUS Password Authentication
- 3.5. System Control
- 4. System YANG module
- 5. IANA Considerations
- 6. Security Considerations
- 7. References
- Authors' Addresses
1. Introduction
This document defines a YANG [RFC6020] data model for the configuration and identification of 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 YANG module defined in this document provides the following features:
- system administrative data configuration
- system identification monitoring
- system time-of-day configuration and monitoring
- user authentication configuration
- local users configuration
1.1. Terminology
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].
1.1.1. Terms
The following terms are used within this document:
- system: This term refers to the embodiment of the entire set of management interfaces that a single NETCONF server is supporting at a given moment. The set of physical entities managed by a single NETCONF server can be static or it can change dynamically.
2. Objectives
2.1. System Identification
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 intended to be specific to the device vendor.
Some user-configurable administrative strings are also provided such as the system location and description.
2.2. System Time Management
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 [I-D.lear-iana-timezone-database] also need to be supported.
2.3. User Authentication
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.
3. System Data Model
3.1. System Identification
The data model for system identification has the following structure:
+--rw system
+--rw contact? string
+--rw name? string
+--rw location? string
+--ro platform
+--ro os-name? string
+--ro os-release? string
+--ro os-version? string
+--ro machine? string
+--ro nodename? string
3.2. System Time Management
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-name)
| | +--rw timezone-name? string
| +--:(timezone-utc-offset)
| +--rw timezone-utc-offset? int16
+--rw ntp
+--rw use-ntp? boolean
+--rw ntp-server [address]
+--rw address inet:host
3.3. DNS Resolver Model
The data model for configuration of the DNS resolver has the following structure:
+--rw system
+--rw dns
+--rw search* inet:host
+--rw server* inet:ip-address
+--rw options
+--rw ndots? uint8
+--rw timeout? uint8
+--rw attempts? uint8
3.4. User Authentication Model
This document defines three authentication methods for use with NETCONF:
- publickey for local users over SSH
- password for local users over any transport
- password for RADIUS users over any transport
Additional methods can be defined by other standard documents or by vendors.
This document defines two optional YANG features, "local‑users" and "radius", which the server advertises to indicate support for configuring local users on the device, and for configuring RADIUS access, 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 radius
| +--rw server [address]
| | +--rw address inet:host
| | +--rw port? inet:port-number
| | +--rw shared-secret? string
| +--rw options
| +--rw timeout? uint8
| +--rw attempts? uint8
+--rw user [name]
+--rw name string
+--rw password? crypt-hash
+--rw ssh-dsa? binary
+--rw ssh-rsa? binary
3.4.1. SSH Public Key Authentication
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].
3.4.2. Local User Password Authentication
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.
3.4.3. RADIUS Password Authentication
If the NETCONF server advertises the "radius" feature, the device supports user authentication 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.
3.5. System Control
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.
4. System YANG module
RFC Ed.: update the date below with the date of RFC publication and remove this note.
This YANG module imports YANG extensions from [I-D.ietf-netconf-access-control], imports YANG types from [RFC6021], and references [RFC1321], [RFC2865], [RFC3418], [RFC5607], [IEEE-1003.1-2008], and [FIPS.180-3.2008].
<CODE BEGINS> file "ietf-system@2011-10-30.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;
}
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.bierman@brocade.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) 2011 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-bierman-netmod-system-mgmt-01.txt
// RFC Ed.: update the date below with the date of RFC publication
// and remove this note.
revision 2011-10-30 {
description
"Initial revision.";
reference
"RFC XXXX: A YANG Data Model for System Management";
}
/*
* Typedefs
*/
typedef crypt-hash {
type string {
pattern "$0$.* | $1|5|6$[a-zA-Z0-9./]{2,16}$.*";
}
description
"The crypt-hash type is used to store passwords using
a hash function. This type is implemented in various UNIX
systems as the function crypt(3).
When a clear text value is set to a leaf of this type, the
server calculates a password hash, and stores the result
in the datastore. Thus, the password is never stored in
clear text.
When a leaf of this type is read, the stored password hash is
returned.
A value of this type matches one of the forms:
$0$<clear text password>
$<id>$<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>$' is prepended to the
result, where <salt> is a random 2-16 characters long salt
used to generate the digest. This value is stored in the
configuration data store.
If a value starting with '$<id>$<salt>$' 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_(Unix)
RFC 1321: The MD5 Message-Digest Algorithm
FIPS.180-3.2008: Secure Hash Standard";
}
/*
* Features
*/
feature authentication {
description
"Indicates that the device can be configured
to do authentication of users.";
}
feature radius {
if-feature authentication;
description
"Indicates that the device can be
configured to act as a NAS and authenticate users
with 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 local-users {
if-feature authentication;
description
"Indicates that the device supports
local user authentication.";
}
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
http://www.ietf.org/id/draft-lear-iana-timezone-database-04.txt
";
}
feature timezone-name {
description
"Indicates that the local timezone on the device
can be configured using the timezone enumeration
strings as an alias for an UTC offset.";
reference
"Wikipedia: http://en.wikipedia.org/wiki/"
+ "List_of_time_zone_abbreviations";
}
/*
* 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.";
}
/*
* Top-level container
*/
container system {
description
"System group configuration.";
leaf contact {
type string {
length "0..255";
}
default "";
reference
"RFC 3418 - Management Information Base (MIB) for the
Simple Network Management Protocol (SNMP)
SNMPv2-MIB.sysContact";
}
leaf name {
type string {
length "0..255";
}
default "";
reference
"RFC 3418 - Management Information Base (MIB) for the
Simple Network Management Protocol (SNMP)
SNMPv2-MIB.sysName";
}
leaf location {
type string {
length "0..255";
}
default "";
reference
"RFC 3418 - Management Information Base (MIB) for the
Simple Network Management Protocol (SNMP)
SNMPv2-MIB.sysLocation";
}
container platform {
description
"Contains vendor-specific information for
identifying the system platform and operating system.";
reference
"IEEE Std 1003.1-2008 - sys/utsname.h";
config false;
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";
}
leaf nodename {
type string;
description
"The host name of this system.";
reference
"IEEE Std 1003.1-2008 - utsname.nodename";
}
}
container clock {
description
"Configuration and monitoring of the system
date and time properties.";
leaf current-datetime {
description
"The current system date and time.";
type yang:date-and-time;
config false;
}
leaf boot-datetime {
description
"The system date and time when the NETCONF
server last restarted.";
type yang:date-and-time;
config false;
}
choice timezone {
description
"Configure the system timezone information.";
leaf timezone-location {
if-feature timezone-location;
description
"The TZ database location identifier string
to use for the system, such as 'Europe/Stockholm'.";
type string;
}
leaf timezone-name {
if-feature timezone-name;
description
"The timezone enumeration string to use
for the system, such as 'CET'.";
type string;
// FIXME: use TimezoneEnum typedef instead
// see http://en.wikipedia.org/wiki/
// List_of_time_zone_abbreviations
}
leaf timezone-utc-offset {
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'.";
type int16 {
range "-1439 .. 1439";
}
}
}
}
container ntp {
if-feature ntp;
description
"Configuration of the NTP client.
FIXME: should NTP server mode be supported here,
or in a submodule? Should NTP client and server
mode be kept together in the same container?";
leaf use-ntp {
description
"Indicates that the system should attempt
to synchronize the system clock with an
NTP server from the 'ntp-server' list.";
type boolean;
default true;
}
list ntp-server {
description
"List of NTP servers to use for
system clock synchronization. If 'use-ntp'
is 'true', then the system will attempt to
contact and utilize the specified NTP servers.";
key address;
leaf address {
description
"The IP address or domain name of the NTP server.";
type inet:host;
}
}
}
container dns {
description
"Configuration of the DNS resolver.";
leaf-list search {
type inet:host;
ordered-by user;
}
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 ndots {
type uint8;
default "1";
}
leaf timeout {
type uint8;
units "seconds";
default "5";
}
leaf attempts {
type uint8;
default "2";
}
}
}
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" and ../radius/server) or'
+ '(. != "sys:radius")' {
error-message
"When 'radius' is used, 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' 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.";
}
container radius {
if-feature radius;
description
"The RADIUS configuration for authentication.";
list server {
key address;
ordered-by user;
description
"The RADIUS server configuration used by
the device.";
leaf address {
type inet:host;
description
"The address of the RADIUS server.";
}
leaf port {
type inet:port-number;
default "1812";
description
"The port number of the RADIUS server.";
}
leaf shared-secret {
type string;
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";
}
}
container options {
description
"RADIUS client options.";
leaf timeout {
type uint8;
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;
default "2";
description
"The number of times the device will send a query to
the RADIUS servers before giving up.";
}
}
}
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.";
}
leaf ssh-dsa {
type binary;
description
"The public DSA key for this entry.";
}
leaf ssh-rsa {
type binary;
description
"The public RSA key for this entry.";
}
}
}
}
rpc set-current-datetime {
nacm:default-deny-all;
description
"Manually set the /system/clock/current-datetime leaf
to the specified value.
If the /system/ntp/ntp-in-use leaf exists and
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 {
description
"The current system date and time.";
type yang:date-and-time;
mandatory true;
}
}
}
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>
5. IANA Considerations
This document registers a 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 a 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
6. Security Considerations
TBD.