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Versions: (draft-badra-netconf-rfc5539bis) 00
01 02 03 04 05 06 07 08 09 10 RFC 7589
NETCONF Working Group M. Badra
Internet-Draft LIMOS Laboratory
Obsoletes: 5539 (if approved) A. Luchuk
Intended status: Standards Track SNMP Research, Inc.
Expires: April 24, 2014 J. Schoenwaelder
Jacobs University Bremen
October 21, 2013
Using the NETCONF Protocol over Transport Layer Security (TLS)
draft-ietf-netconf-rfc5539bis-04
Abstract
The Network Configuration Protocol (NETCONF) provides mechanisms to
install, manipulate, and delete the configuration of network devices.
This document describes how to use the Transport Layer Security (TLS)
protocol to secure the exchange of NETCONF messages. This document
obsoletes RFC 5539.
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 April 24, 2014.
Copyright Notice
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
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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 . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Applicability Statement . . . . . . . . . . . . . . . . . 3
2. NETCONF over TLS . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Connection Initiation . . . . . . . . . . . . . . . . . . 4
2.1.1. Client to Server . . . . . . . . . . . . . . . . . . . 4
2.1.2. Server to Client (Call Home) . . . . . . . . . . . . . 4
2.2. Message Framing . . . . . . . . . . . . . . . . . . . . . 4
2.3. Connection Closure . . . . . . . . . . . . . . . . . . . . 5
2.4. X.509-based Authentication, Identification and
Authorization . . . . . . . . . . . . . . . . . . . . . . 5
2.4.1. Server Identity . . . . . . . . . . . . . . . . . . . 5
2.4.2. Client Identity . . . . . . . . . . . . . . . . . . . 6
2.5. Pre-Shared-Key-based Authentication, Identification
and Authorization . . . . . . . . . . . . . . . . . . . . 6
2.6. Cipher Suites . . . . . . . . . . . . . . . . . . . . . . 7
3. Data Model Overview . . . . . . . . . . . . . . . . . . . . . 7
4. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 9
4.1. Module 'ietf-netconf-config' . . . . . . . . . . . . . . . 9
4.2. Submodule 'ietf-netconf-common' . . . . . . . . . . . . . 10
4.3. Submodule 'ietf-netconf-tls' . . . . . . . . . . . . . . . 12
5. Usage Examples . . . . . . . . . . . . . . . . . . . . . . . . 18
5.1. Certificate Mapping Configuration Example . . . . . . . . 18
5.2. PSK Mapping Configuration Example . . . . . . . . . . . . 19
5.3. Call-Home Configuration Example . . . . . . . . . . . . . 19
6. Security Considerations . . . . . . . . . . . . . . . . . . . 20
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 22
9. Contributor's Address . . . . . . . . . . . . . . . . . . . . 23
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 23
10.1. Normative References . . . . . . . . . . . . . . . . . . . 23
10.2. Informative References . . . . . . . . . . . . . . . . . . 24
Appendix A. Change Log (to be removed by RFC Editor before
publication) . . . . . . . . . . . . . . . . . . . . 24
A.1. draft-ietf-netconf-rfc5539bis-03 . . . . . . . . . . . . . 24
A.2. draft-ietf-netconf-rfc5539bis-03 . . . . . . . . . . . . . 25
A.3. draft-ietf-netconf-rfc5539bis-02 . . . . . . . . . . . . . 25
A.4. draft-ietf-netconf-rfc5539bis-00 . . . . . . . . . . . . . 26
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 26
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1. Introduction
The NETCONF protocol [RFC6241] defines a mechanism through which a
network device can be managed. NETCONF is connection-oriented,
requiring a persistent connection between peers. This connection
must provide integrity, confidentiality, peer authentication, and
reliable, sequenced data delivery.
This document defines "NETCONF over TLS", which includes support for
certificate and pre-shared key (PSK)-based authentication and key
derivation, utilizing the protected ciphersuite negotiation, mutual
authentication, and key management capabilities of the TLS (Transport
Layer Security) protocol, described in [RFC5246]. It also provides
an optional mechanism to establish the underlying TCP connection from
the NETCONF server to the NETCONF client (call home). A YANG data
model is provided for configuring the policy used to map X.509
certificates into NETCONF usernames and to provision TLS pre-shared
keys and to associate these keys with NETCONF usernames. It also
provides configuration objects to configure the call home policy.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
1.1. Applicability Statement
The "call home" technique described in Section 2.1.2 of this document
MUST only be used for a NETCONF server to initiate a connection to a
NETCONF client, as described in this document.
The reason for this restriction is that different protocols have
different security assumptions. This specification requires NETCONF
clients and servers to verify the identity of the other party before
the NETCONF session is started. Further, strong cryptographic
authentication is used for both the NETCONF client and server. This
reduces the risk that a malicious party could impersonate a NETCONF
server and contact the NETCONF client using the "call home"
technique. Protocols other than NETCONF might not be so well
protected.
2. NETCONF over TLS
Since TLS is application-protocol-independent, NETCONF can operate on
top of the TLS protocol transparently. This document defines how
NETCONF can be used within a TLS session.
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2.1. Connection Initiation
In many deployments, the NETCONF client will initiate the connection
to a NETCONF server as described in Section 2.1.1. However, in order
to use NETCONF in environments where middleboxes prevent the client
from establishing the connection, the server may initiate the
connection as described in Section 2.1.2 (call home).
2.1.1. Client to Server
The peer acting as the NETCONF client MUST act as the TLS client.
The TLS client actively opens the TLS connection and the TLS server
passively listens for the incoming TLS connection on the TCP port
6513. The TLS client MUST therefore send the TLS ClientHello message
to begin the TLS handshake. Once the TLS handshake has finished, the
client and the server MAY begin to exchange NETCONF messages. Client
and server identity verification (as described in Section 2.4 and
Section 2.5) is done before the <hello> message is sent. This means
that the identity verification is completed before the NETCONF
session has started.
2.1.2. Server to Client (Call Home)
The peer acting as the NETCONF server first actively opens a TCP
connection to the NETCONF client using the default port number YYYY.
Once the connection has been established, the NETCONF client, which
has accepted the incoming TCP connection, takes initiative. It from
now on MUST act as the TLS client and it therefore sends the TLS
ClientHello message to begin the TLS handshake. Once the TLS
handshake has finished, the client and the server MAY begin to
exchange NETCONF messages. Client and server identity verification
(as described in Section 2.4 and Section 2.5) is done before the
<hello> message is sent. This means that the identity verification
is completed before the NETCONF session has started.
2.2. Message Framing
All NETCONF messages MUST be sent as TLS "application data". It is
possible that multiple NETCONF messages be contained in one TLS
record, or that a NETCONF message be transferred in multiple TLS
records.
The previous version [RFC5539] of this document used the framing
sequence defined in [RFC4742], under the assumption that it could not
be found in well-formed XML documents. However, this assumption is
not correct [RFC6242]. In order to solve this problem, this document
adopts the framing protocol defined in [RFC6242] as follows:
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The <hello> message MUST be followed by the character sequence
]]>]]>. Upon reception of the <hello> message, the receiving peer's
TLS Transport layer conceptually passes the <hello> message to the
Messages layer. If the :base:1.1 capability is advertised by both
peers, the chunked framing mechanism defined in Section 4.2 of
[RFC6242] is used for the remainder of the NETCONF session.
Otherwise, the old end-of-message-based mechanism (see Section 4.3 of
[RFC6242]) is used.
2.3. Connection Closure
A NETCONF server will process NETCONF messages from the NETCONF
client in the order in which they are received. A NETCONF session is
closed using the <close-session> operation. When the NETCONF server
processes a <close-session> operation, the NETCONF server SHALL
respond and close the TLS session as described in [RFC5246] Section
7.2.1. The NETCONF server MUST NOT process any NETCONF messages
received after the <close-session> operation.
2.4. X.509-based Authentication, Identification and Authorization
Implementations MAY optionally support TLS certificate-based
authentication [RFC5246]. If the implementation supports TLS
certificate-based authentication, then the following sections apply.
2.4.1. Server Identity
If the certificate presented by a NETCONF server has passed
certification path validation [RFC5280] to a configured trust anchor,
the NETCONF client MUST carefully examine the certificate presented
by the server to determine if it meets the client's expectations.
Particularly, the NETCONF client MUST check its understanding of the
NETCONF server hostname against the server's identity as presented in
the server Certificate message, in order to prevent man-in-the-middle
attacks.
Matching is performed according to the rules and guidelines defined
in [RFC6125]. If the match fails, the NETCONF client MUST either ask
for explicit user confirmation or terminate the connection and
indicate the NETCONF server's identity is suspect.
Additionally, NETCONF clients MUST verify the binding between the
identity of the NETCONF servers to which they connect and the public
keys presented by those servers. NETCONF clients SHOULD implement
the algorithm in Section 6 of [RFC5280] for general certificate
validation, but MAY supplement that algorithm with other validation
methods that achieve equivalent levels of verification (such as
comparing the NETCONF server certificate against a local store of
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already-verified certificates and identity bindings).
If the NETCONF client has external information as to the expected
identity of the NETCONF server, the hostname check MAY be omitted.
2.4.2. Client Identity
The NETCONF server MUST verify the identity of the NETCONF client to
ensure that the incoming request to establish a NETCONF session is
legitimate before the NETCONF session is started.
The NETCONF protocol [RFC6241] requires that the transport protocol's
authentication process MUST result in an authenticated NETCONF client
identity whose permissions are known to the server. The
authenticated identity of a client is commonly referred to as the
NETCONF username.
The username provided by the NETCONF over TLS implementation will be
made available to the NETCONF message layer as the NETCONF username
without modification. If the username does not comply to the NETCONF
requirements on usernames [RFC6241], i.e., the username is not
representable in XML, the TLS session MUST be dropped.
2.4.2.1. Deriving NETCONF Usernames from X.509 Certificates
After completing the TLS handshake, the NETCONF server attempts to
derive a NETCONF username from the X.509 certificate presented by the
NETCONF client. If the NETCONF server cannot derive a valid NETCONF
username from the presented certificate, then the NETCONF server MUST
close the TLS connection, and MUST NOT accept NETCONF messages over
it. The NETCONF server uses the algorithm defined in
[I-D.ietf-netmod-snmp-cfg] to extract a NETCONF username from the
X.509 certificate presented by the NETCONF client. The cert-to-name
list in the ietf-netconf-tls YANG submodule specifies how a NETCONF
server transforms a certificate into a NETCONF username.
2.5. Pre-Shared-Key-based Authentication, Identification and
Authorization
Implementations MAY optionally support TLS Pre-Shared Key (PSK)
authentication [RFC4279]. RFC4279 describes pre-shared key
ciphersuites for TLS. The description of the psk-maps container in
the ietf-netconf-tls YANG submodule, defined in Section 4.3,
specifies how a NETCONF server associates a TLS pre-shared key with a
NETCONF username.
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2.6. Cipher Suites
Implementations of the protocol specified in this document MAY
implement any TLS cipher suite that provides mutual authentication
[RFC5246]. However, implementations MUST support TLS 1.2 [RFC5246]
and are REQUIRED to support the mandatory-to-implement cipher suite,
which is TLS_RSA_WITH_AES_128_CBC_SHA. This document is assumed to
apply to future versions of TLS; in which case, the mandatory-to-
implement cipher suite for the implemented version MUST be supported.
3. Data Model Overview
In order to support future extensibility of the NETCONF configuration
data model, the YANG definitions have been organized in a set of YANG
submodules, all sharing the same module namespace.
o ietf-netconf-config: The module importing the submodules and
defining the module namespace.
o ietf-netconf-common: The submodule providing common definitions
shared by all submodules.
o ietf-netconf-tls: The submodule defining configuration objects for
the NETCONF over TLS transport.
This organization allows to add configuration support for additional
NETCONF features while keeping the number of namespaces that have to
be dealt with down to a minimum. If new definitions need to be added
to the NETCONF configuration data model, either an existing YANG
submodule can be updated or a new YANG submodule can be written. In
both cases, the new document will carry an updated version of the
"ietf-netconf-config" module importing the submodules.
The YANG submodule "ietf-netconf-tls" defines (i) how to configure
the policy used to map X.509 certificates into NETCONF usernames and
(ii) the mechanisms used to provision pre-shared keys and to
associate them with NETCONF usernames. The mapping of X.509
certificates to NETCONF usernames imports definitions from [RFC6536]
and [I-D.ietf-netmod-snmp-cfg].
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+--rw netconf
+--rw tls
+--rw enabled? boolean
+--rw cert-maps {tls-map-certificates}?
| +--rw cert-to-name* [id]
| +--rw id uint32
| +--rw fingerprint x509c2n:tls-fingerprint
| +--rw map-type identityref
| +--rw name string
+--rw psk-maps {tls-map-pre-shared-keys}?
| +--rw psk-map* [psk-identity]
| +--rw psk-identity string
| +--rw user-name nacm:user-name-type
| +--rw not-valid-before? yang:date-and-time
| +--rw not-valid-after? yang:date-and-time
| +--rw key yang:hex-string
+--rw call-home {tls-call-home}?
+--rw client* [address port]
+--rw address inet:host
+--rw port inet:port-number
+--rw (connection-type)?
| +--:(persistent)
| | +--rw persistent-connection? empty
| +--:(periodic)
| +--rw periodic
| +--rw interval? uint16
| +--rw linger? uint16
+--rw reconnect-strategy
+--rw retry-interval? uint16
+--rw max-attempts? uint16
The meaning of the symbols in this diagrams is as follows:
o Brackets "[" and "]" enclose list keys.
o Abbreviations before data node names: "rw" means configuration
(read-write) and "ro" state data (read-only).
o Symbols after data node names: "?" means an optional node, "!"
means a presence container, and "*" denotes a "list" and "leaf-
list".
o Parentheses enclose choice and case nodes, and case nodes are also
marked with a colon (":").
o Ellipsis ("...") stands for contents of subtrees that are not
shown.
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4. Definitions
The YANG modules and submodules import type definitions and groupings
from [RFC6991], [RFC6536], and [I-D.ietf-netmod-snmp-cfg].
4.1. Module 'ietf-netconf-config'
<CODE BEGINS> file "ietf-netconf-config@2013-10-21.yang"
module ietf-netconf-config {
namespace "urn:ietf:params:xml:ns:yang:ietf-netconf-config";
prefix "ncconf";
include ietf-netconf-common {
revision-date 2013-10-21;
}
include ietf-netconf-tls {
revision-date 2013-10-21;
}
organization
"IETF NETCONF (Network Configuration) Working Group";
contact
"WG Web: <http://tools.ietf.org/wg/netconf/>
WG List: <mailto:netconf@ietf.org>
WG Chair: Mehmet Ersue
<mailto:mehmet.ersue@nsn.com>
WG Chair: Bert Wijnen
<mailto:bertietf@bwijnen.net>
Editor: Mohamad Badra
<mailto:mbadra@gmail.com>
Alan Luchuk
<mailto:luchuk@snmp.com>
Juergen Schoenwaelder
<mailto:j.schoenwaelder@jacobs-university.de>";
description
"This module contains a collection of YANG definitions for
configuring NETCONF servers.
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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.: please update the date to the date of publication
revision "2013-10-21" {
description
"Initial version";
reference
"RFC XXXX: NETCONF over Transport Layer Security (TLS)";
}
}
<CODE ENDS>
4.2. Submodule 'ietf-netconf-common'
<CODE BEGINS> file "ietf-netconf-common@2013-10-21.yang"
submodule ietf-netconf-common {
belongs-to ietf-netconf-config {
prefix ncconf;
}
organization
"IETF NETCONF (Network Configuration) Working Group";
contact
"WG Web: <http://tools.ietf.org/wg/netconf/>
WG List: <mailto:netconf@ietf.org>
WG Chair: Mehmet Ersue
<mailto:mehmet.ersue@nsn.com>
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WG Chair: Bert Wijnen
<mailto:bertietf@bwijnen.net>
Editor: Mohamad Badra
<mailto:mbadra@gmail.com>
Alan Luchuk
<mailto:luchuk@snmp.com>
Juergen Schoenwaelder
<mailto:j.schoenwaelder@jacobs-university.de>";
description
"This submodule contains a collection of common YANG definitions
for configuring NETCONF servers.
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.: please update the date to the date of publication
revision "2013-10-21" {
description
"Initial version";
reference
"RFC XXXX: NETCONF over Transport Layer Security (TLS)";
}
container netconf {
description
"Top-level container for NETCONF related configuration
objects.";
}
}
<CODE ENDS>
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4.3. Submodule 'ietf-netconf-tls'
<CODE BEGINS> file "ietf-netconf-tls@2013-10-21.yang"
submodule ietf-netconf-tls {
belongs-to ietf-netconf-config {
prefix ncconf;
}
import ietf-yang-types {
prefix yang;
}
import ietf-inet-types {
prefix inet;
}
import ietf-netconf-acm {
prefix nacm;
}
import ietf-x509-cert-to-name {
prefix x509c2n;
}
include ietf-netconf-common;
organization
"IETF NETCONF (Network Configuration) Working Group";
contact
"WG Web: <http://tools.ietf.org/wg/netconf/>
WG List: <mailto:netconf@ietf.org>
WG Chair: Mehmet Ersue
<mailto:mehmet.ersue@nsn.com>
WG Chair: Bert Wijnen
<mailto:bertietf@bwijnen.net>
Editor: Mohamad Badra
<mailto:mbadra@gmail.com>
Alan Luchuk
<mailto:luchuk@snmp.com>
Juergen Schoenwaelder
<mailto:j.schoenwaelder@jacobs-university.de>";
description
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"This submodule applies to NETCONF over TLS. It specifies how
NETCONF servers transform X.509 certificates presented by
NETCONF clients into NETCONF usernames. It also specifies
how NETCONF servers transform pre-shared TLS keys into NETCONF
usernames.
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.: please update the date to the date of publication
revision "2013-10-21" {
description
"Initial version";
reference
"RFC XXXX: NETCONF over Transport Layer Security (TLS)";
}
feature tls {
description
"A server implements this feature if it supports NETCONF
over Transport Layer Security (TLS).";
reference
"RFC XXXX: NETCONF over Transport Layer Security (TLS)";
}
feature tls-map-certificates {
description
"The tls-map-certificates feature indicates that the
server implements mapping X.509 certificates to NETCONF
usernames.";
}
feature tls-map-pre-shared-keys {
description
"The tls-map-pre-shared-keys feature indicates that the
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server implements mapping TLS pre-shared keys to NETCONF
usernames.";
}
feature tls-call-home {
description
"The tls-call-home feature indicates that the server can
connect to a client.";
}
augment /ncconf:netconf {
if-feature tls;
container tls {
leaf enabled {
type boolean;
default "false";
description
"Enables NETCONF over Transport Layer Security (TLS).";
}
// Objects for deriving NETCONF usernames from X.509
// certificates.
container cert-maps {
if-feature tls-map-certificates;
uses x509c2n:cert-to-name;
description
"The cert-maps container is used by a NETCONF server to
map the NETCONF client's presented X.509 certificate to
a NETCONF username.
If no matching and valid cert-to-name list entry can be
found, then the NETCONF server MUST close the connection,
and MUST NOT accept NETCONF messages over it.";
}
// Objects for deriving NETCONF usernames from TLS
// pre-shared keys.
container psk-maps {
if-feature tls-map-pre-shared-keys;
description
"During the TLS Handshake, the client indicates which
key to use by including a PSK identity in the TLS
ClientKeyExchange message. On the server side, this
PSK identity is used to look up an entry in the psk-map
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list. If such an entry is found, and the pre-shared keys
match, then the client is authenticated. The server uses
the value from the user-name leaf in the psk-map list as
the NETCONF username. If the server cannot find an entry
in the psk-map list, or if the pre-shared keys do not
match, then the server terminates the connection.";
reference
"RFC 4279: Pre-Shared Key Ciphersuites for Transport Layer
Security (TLS)";
list psk-map {
key psk-identity;
leaf psk-identity {
type string;
description
"The PSK identity encoded as a UTF-8 string. For
details how certain common PSK identity formats can
be encoded in UTF-8, see section 5.1. of RFC 4279.";
reference
"RFC 4279: Pre-Shared Key Ciphersuites for Transport
Layer Security (TLS)";
}
leaf user-name {
type nacm:user-name-type;
mandatory true;
description
"The NETCONF username associated with this PSK
identity.";
}
leaf not-valid-before {
type yang:date-and-time;
description
"This PSK identity is not valid before the given date
and time.";
}
leaf not-valid-after {
type yang:date-and-time;
description
"This PSK identity is not valid after the given date
and time.";
}
leaf key {
type yang:hex-string;
mandatory true;
nacm:default-deny-all;
description
"The key associated with the PSK identity";
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reference
"RFC 4279: Pre-Shared Key Ciphersuites for Transport
Layer Security (TLS)";
}
} // list psk-map
} // container psk-maps
// XXX
// Objects for determining where to connect to, how frequently,
// and how to reconnect should a connection break. This ideally
// would be a common grouping for both NETCONF over TLS and
// NETCONF over SSH.
container call-home {
if-feature tls-call-home;
description
"Provides the configuration of the NETCONF call-home
clients to connect to, the overall call-home policy,
and the reconnect strategy.";
list client {
key "address port";
leaf address {
type inet:host;
description
"The address of the call-home client to connect to.";
}
leaf port {
type inet:port-number;
// default 8888;
description
"The port number of the call-home client to connect to.";
}
choice connection-type {
case persistent {
leaf persistent-connection {
type empty;
description
"Maintain a persistent connection to the call-home
client.";
}
}
case periodic {
container periodic {
leaf interval {
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type uint16; // ssh had uint8 ?
units minutes;
default 5;
description
"The maximum amount of unconnected time the device
will wait until establishing a connection to the
call-home client again. The device may establish
a connection before this time.";
}
leaf linger {
type uint16; // ssh had uint8 ?
units seconds;
default 30;
description
"The amount of time the device should wait after
last receiving data from or sending data to the
call-home client before closing the connection.";
}
}
}
}
// XXX
// Should we have something smarter as the reconnect
// strategy, e.g. an exponential backoff? What about
// a persistent connection that fails for say a week?
// One would hope that the box still attempts to
// connect so that it can recover once it comes back
// online.
container reconnect-strategy {
leaf retry-interval {
type uint16; // ssh had uint8 ?
units seconds;
default 5;
description
"Time delay between two subsequent connection
attempts to the call-home client.";
}
leaf max-attempts {
type uint16; // ssh had uint8 ?
default 3;
description
"Number of times to try to connect to a call-home
client.";
}
}
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// XXX
// Do we need objects to configure which cert / psk
// to expect to use when attempting a call-home?
}
} // container call-home
}
}
}
<CODE ENDS>
5. Usage Examples
5.1. Certificate Mapping Configuration Example
The following XML shows an example configuration mapping a specific
X.509 certificate to a NETCONF username:
<netconf xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-config"
xmlns:x509c2n="urn:ietf:params:xml:ns:yang:ietf-x509-cert-to-name">
<tls>
<enabled>true</enabled>
<cert-maps>
<!-- Use a subject alt name field of a specific
certificate as the NC username. -->
<cert-to-name>
<id>1</id>
<fingerprint>11:0A:05:11:00</fingerprint>
<map-type>x509c2n:san-any</map-type>
</cert-to-name>
<!-- Map a specific certificate to the NC username
'Joe Cool'. -->
<cert-to-name>
<id>2</id>
<fingerprint>11:0A:05:11:00</fingerprint>
<map-type>x509c2n:specified</map-type>
<name>Joe Cool</name>
</cert-to-name>
</cert-maps>
</tls>
</netconf>
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5.2. PSK Mapping Configuration Example
The following XML shows an example configuration mapping a pre-shared
key to a NETCONF username:
<netconf xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-config">
<tls>
<enabled>true</enabled>
<psk-maps>
<psk-map>
<psk-identity>a8gc8]klh59</psk-identity>
<user-name>admin</user-name>
<not-valid-before>2013-01-01T00:00:00-00:00</not-valid-before>
<not-valid-after>2014-01-01T00:00:00-00:00</not-valid-after>
</psk-map>
</psk-maps>
</tls>
</netconf>
5.3. Call-Home Configuration Example
The following XML shows an example configuration for call-home.
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<netconf xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-config">
<tls>
<enabled>true</enabled>
<call-home>
<client>
<address>netconf.example.com</address>
<port>8888</port>
<persistent-connection/>
<reconnect-strategy>
<retry-interval>30</retry-interval>
<max-attempts>10</max-attempts>
</reconnect-strategy>
</client>
<client>
<address>netconf.example.com</address>
<port>9999</port>
<periodic>
<interval>5</interval>
<linger>10</linger>
</periodic>
<reconnect-strategy>
<retry-interval>30</retry-interval>
<max-attempts>10</max-attempts>
</reconnect-strategy>
</client>
</call-home>
</tls>
</netconf>
6. Security Considerations
The security considerations described throughout [RFC5246] and
[RFC6241] apply here as well.
This document in its current version does not support third-party
authentication (e.g., backend Authentication, Authorization, and
Accounting (AAA) servers) due to the fact that TLS does not specify
this way of authentication and that NETCONF depends on the transport
protocol for the authentication service. If third-party
authentication is needed, SSH transport can be used.
An attacker might be able to inject arbitrary NETCONF messages via
some application that does not carefully check exchanged messages.
When the :base:1.1 capability is not advertised by both peers, an
attacker might be able to deliberately insert the delimiter sequence
]]>]]> in a NETCONF message to create a DoS attack. If the :base:1.1
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capability is not advertised by both peers, applications and NETCONF
APIs MUST ensure that the delimiter sequence ]]>]]> never appears in
NETCONF messages; otherwise, those messages can be dropped, garbled,
or misinterpreted. More specifically, if the delimiter sequence is
found in a NETCONF message by the sender side, a robust
implementation of this document SHOULD warn the user that illegal
characters have been discovered. If the delimiter sequence is found
in a NETCONF message by the receiver side (including any XML
attribute values, XML comments, or processing instructions), a robust
implementation of this document MUST silently discard the message
without further processing and then stop the NETCONF session.
Finally, this document does not introduce any new security
considerations compared to [RFC6242].
7. IANA Considerations
Based on the previous version of this document, RFC 5539, IANA has
assigned a TCP port number (6513) in the "Registered Port Numbers"
range with the service name "netconf-tls". This port will be the
default port for NETCONF over TLS, as defined in Section 2.1.1.
Below is the registration template following the rules in [RFC6335].
Service Name: netconf-tls
Transport Protocol(s): TCP
Assignee: IESG <iesg@ietf.org>
Contact: IETF Chair <chair@ietf.org>
Description: NETCONF over TLS
Reference: RFC XXXX
Port Number: 6513
This document requests that IANA assigns a TCP port number in the
"Registered Port Numbers" range with the service name
"netconf-tls-ch". This port will be the default port for NETCONF
over TLS when the NETCONF server calls home, as defined in
Section 2.1.2. Below is the registration template following the
rules in [RFC6335].
Service Name: netconf-tls-ch
Transport Protocol(s): TCP
Assignee: IESG <iesg@ietf.org>
Contact: IETF Chair <chair@ietf.org>
Description: NETCONF over TLS (call home)
Reference: RFC XXXX
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Port Number: YYYY
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-netconf-config
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-netconf-config
namespace: urn:ietf:params:xml:ns:yang:ietf-netconf-config
prefix: ncconf
reference: RFC XXXX
The document registers the following YANG submodules in the YANG
Module Names registry [RFC6020].
name: ietf-netconf-common
parent: ietf-netconf-config
reference: RFC XXXX
name: ietf-netconf-tls
parent: ietf-netconf-config
reference: RFC XXXX
8. Acknowledgements
A significant amount of the text in Section 2.4 was lifted from
[RFC4642].
The authors like to acknowledge Martin Bjorklund, Olivier Coupelon,
Mehmet Ersue, Miao Fuyou, David Harrington, Alfred Hoenes, Simon
Josefsson, Eric Rescorla, Dan Romascanu, Kent Watsen, Bert Wijnen and
the NETCONF mailing list members for their comments on this document.
Charlie Kaufman, Pasi Eronen, and Tim Polk provided a the thorough
review of previous versions of this document. Stephen Hanna wrote
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the initial text for the applicability statement.
Juergen Schoenwaelder and was partly funded by Flamingo, a Network of
Excellence project (ICT-318488) supported by the European Commission
under its Seventh Framework Programme.
9. Contributor's Address
Ibrahim Hajjeh
Ineovation
France
EMail: ibrahim.hajjeh@ineovation.fr
10. References
10.1. Normative References
[I-D.ietf-netmod-snmp-cfg]
Bjorklund, M. and J. Schoenwaelder, "A YANG Data Model for
SNMP Configuration", draft-ietf-netmod-snmp-cfg-02 (work
in progress), April 2013.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4279] Eronen, P. and H. Tschofenig, "Pre-Shared Key Ciphersuites
for Transport Layer Security (TLS)", RFC 4279,
December 2005.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246, August 2008.
[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
Housley, R., and W. Polk, "Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 5280, May 2008.
[RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the
Network Configuration Protocol (NETCONF)", RFC 6020,
October 2010.
[RFC6125] Saint-Andre, P. and J. Hodges, "Representation and
Verification of Domain-Based Application Service Identity
within Internet Public Key Infrastructure Using X.509
(PKIX) Certificates in the Context of Transport Layer
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Security (TLS)", RFC 6125, March 2011.
[RFC6241] Enns, R., Bjorklund, M., Schoenwaelder, J., and A.
Bierman, "Network Configuration Protocol (NETCONF)",
RFC 6241, June 2011.
[RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure
Shell (SSH)", RFC 6242, June 2011.
[RFC6335] Cotton, M., Eggert, L., Touch, J., Westerlund, M., and S.
Cheshire, "Internet Assigned Numbers Authority (IANA)
Procedures for the Management of the Service Name and
Transport Protocol Port Number Registry", BCP 165,
RFC 6335, August 2011.
[RFC6536] Bierman, A. and M. Bjorklund, "Network Configuration
Protocol (NETCONF) Access Control Model", RFC 6536,
March 2012.
[RFC6991] Schoenwaelder, J., "Common YANG Data Types", RFC 6991,
July 2013.
10.2. Informative References
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
January 2004.
[RFC4642] Murchison, K., Vinocur, J., and C. Newman, "Using
Transport Layer Security (TLS) with Network News Transfer
Protocol (NNTP)", RFC 4642, October 2006.
[RFC4742] Wasserman, M. and T. Goddard, "Using the NETCONF
Configuration Protocol over Secure SHell (SSH)", RFC 4742,
December 2006.
[RFC5539] Badra, M., "NETCONF over Transport Layer Security (TLS)",
RFC 5539, May 2009.
Appendix A. Change Log (to be removed by RFC Editor before publication)
A.1. draft-ietf-netconf-rfc5539bis-03
o Added the applicability statement proposed by Stephen Hanna.
o Added call-home configuration objects and a tls-call-home feature.
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o Rewrote the text such that the role swap happens right after the
TCP connection has been established.
A.2. draft-ietf-netconf-rfc5539bis-03
o Added support for call home (allocation of a new port number,
rewrote text to allow a NETCONF client to be a TLS server and a
NETCONF server to be a TLS client).
o Merged sections 2 and 3 into a new section 2 and restructured the
text.
o Extended the IANA considerations section.
o Using the cert-to-name mapping grouping from the SNMP
configuration data model and updated the examples.
o Creating an extensible set of YANG (sub)modules for NETCONF
following the (sub)module structure of the SNMP configuration
model.
A.3. draft-ietf-netconf-rfc5539bis-02
o Addressed remaining issues identified at IETF 85
* Harmonized the cert-maps container of the YANG module in this
draft with the tlstm container in the ietf-snmp-tls sub-module
specified in draft-ietf-netmod-snmp-cfg. Replaced the children
of the cert-maps container with the children copied from the
tlstm container of the ietf-snmp-tls sub-module.
* Added an overview of data model in the ietf-netconf-tls YANG
module.
* Added example configurations.
o Addessed issues posted on NETCONF WG E-mail list.
o Deleted the superfluous tls container that was directly below the
netconf-config container.
o Added a statement to the text indicating that support for mapping
X.509 certificates to NETCONF usernames is optional. This is
analogous to existing text indicating that support for mapping
pre-shared keys to NETCONF usernames is optional. Resource-
constrained systems now can omit support for mapping X.509
certificates to NETCONF usernames and still comply with this
specification.
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o Clarified the document structure by promoting the sections of the
document related to the data model.
o Updated author's addresses.
A.4. draft-ietf-netconf-rfc5539bis-00
o Remove the reference to BEEP.
o Rename host-part to domain-part in the description of RFC822.
Authors' Addresses
Mohamad Badra
LIMOS Laboratory
Email: mbadra@gmail.com
Alan Luchuk
SNMP Research, Inc.
3001 Kimberlin Heights Road
Knoxville, TN 37920
US
Phone: +1 865 573 1434
Email: luchuk@snmp.com
URI: http://www.snmp.com/
Juergen Schoenwaelder
Jacobs University Bremen
Campus Ring 1
28759 Bremen
Germany
Phone: +49 421 200 3587
Email: j.schoenwaelder@jacobs-university.de
URI: http://www.jacobs-university.de/
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