Using the NETCONF Protocol over Transport Layer Security (TLS)
draft-ietf-netconf-rfc5539bis-02
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft that was ultimately published as RFC 7589.
|
|
|---|---|---|---|
| Authors | Mohamad Badra , Alan Luchuk , Jürgen Schönwälder | ||
| Last updated | 2013-02-21 | ||
| Replaces | draft-badra-netconf-rfc5539bis | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
| Formats | |||
| Reviews | |||
| Additional resources | Mailing list discussion | ||
| Stream | WG state | WG Document | |
| Document shepherd | (None) | ||
| IESG | IESG state | Became RFC 7589 (Proposed Standard) | |
| Consensus boilerplate | Unknown | ||
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-ietf-netconf-rfc5539bis-02
NETCONF Working Group M. Badra
Internet-Draft LIMOS Laboratory
Obsoletes: 5539 (if approved) A. Luchuk
Intended status: Standards Track SNMP Research, Inc.
Expires: August 25, 2013 J. Schoenwaelder
Jacobs University Bremen
February 21, 2013
Using the NETCONF Protocol over Transport Layer Security (TLS)
draft-ietf-netconf-rfc5539bis-02
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 NETCONF exchanges. 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 August 25, 2013.
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
2. NETCONF over TLS . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Connection Initiation . . . . . . . . . . . . . . . . . . 3
2.2. Connection Closure . . . . . . . . . . . . . . . . . . . . 4
3. Endpoint Authentication, Identification and Authorization . . 4
3.1. Server Identity . . . . . . . . . . . . . . . . . . . . . 4
3.2. Client Identity . . . . . . . . . . . . . . . . . . . . . 5
3.2.1. Deriving NETCONF Usernames From NETCONF Client
Certificates . . . . . . . . . . . . . . . . . . . . . 5
3.2.2. Deriving NETCONF Usernames From PSK Identities . . . . 7
4. Data Model . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4.1. Data Model Overview . . . . . . . . . . . . . . . . . . . 7
4.2. YANG Module . . . . . . . . . . . . . . . . . . . . . . . 7
5. Usage Examples . . . . . . . . . . . . . . . . . . . . . . . . 15
5.1. Certificate Mapping Configuration Example . . . . . . . . 15
5.2. PSK Mapping Configuration Example . . . . . . . . . . . . 15
6. Security Considerations . . . . . . . . . . . . . . . . . . . 15
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 17
9. Contributor's Address . . . . . . . . . . . . . . . . . . . . 17
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 17
10.1. Normative References . . . . . . . . . . . . . . . . . . . 17
10.2. Informative References . . . . . . . . . . . . . . . . . . 18
Appendix A. Change Log (to be removed by RFC Editor before
publication) . . . . . . . . . . . . . . . . . . . . 18
A.1. Open Issues . . . . . . . . . . . . . . . . . . . . . . . 18
A.2. From draft-ietf-netconf-rfc5539bis-01 to
draft-ietf-netconf-rfc5539bis-02 . . . . . . . . . . . . . 19
A.3. From draft-badra-netconf-rfc5539bis-02 to
draft-ietf-netconf-rfc5539bis-00 . . . . . . . . . . . . . 19
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19
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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].
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].
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.
2.1. Connection Initiation
The peer acting as the NETCONF client MUST also 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 3) is done before the <hello> message is sent; for the
server, this means the identity verification is completed before the
NETCONF session has started.
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, and at the
same time be compatible with existing implementations, this document
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uses the framing protocol defined in [RFC6242] as following:
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.
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.
2.2. Connection Closure
Exiting NETCONF is accomplished using the <close-session> operation.
A NETCONF server will process NETCONF messages from the NETCONF
client in the order in which they are received. When the NETCONF
server processes a <close-session> operation, the NETCONF server
SHALL respond and close the TLS session. The NETCONF server MUST NOT
process any NETCONF messages received after the <close-session>
operation. The TLS session is closed as described in [RFC5246]
Section 7.2.1.
3. Endpoint 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.
3.1. Server Identity
If the server's presented certificate has passed certification path
validation [RFC5280] to a configured trust anchor, the client MUST
carefully examine the certificate presented by the server to
determine if it meets the client's expectations. Particularly, the
client MUST check its understanding of the 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
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in [RFC6125].
If the match fails, the client MUST either ask for explicit user
confirmation or terminate the connection and indicate the server's
identity is suspect.
Additionally, clients MUST verify the binding between the identity of
the servers to which they connect and the public keys presented by
those servers. 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 server certificate
against a local store of already-verified certificates and identity
bindings).
If the client has external information as to the expected identity of
the server, the hostname check MAY be omitted.
3.2. Client Identity
The server MUST verify the identity of the client to ensure that the
incoming client request 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 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 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.
Algorithms for mapping certificates or PSK identities (sent by the
client) to NETCONF usernames are described below.
3.2.1. Deriving NETCONF Usernames From NETCONF Client Certificates
The algorithm for deriving NETCONF usernames from TLS certificates is
patterned after the algorithm for deriving tmSecurityNames from TLS
certificates specified in the Transport Layer Security (TLS)
Transport Model for the Simple Network Management Protocol (SNMP)
[RFC6353]. The NETCONF server MUST implement the algorithms for
deriving NETCONF usernames from presented certificates that are
documented in the ietf-netconf-tls YANG module, defined in
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Section 4.2. This YANG module lets the NETCONF security
administrator configure how the NETCONF server derives NETCONF
usernames from presented certificates. It also lets different
certificate-to-username derivation algorithms be used for different
certificates.
When a NETCONF server accepts a TLS connection from a NETCONF client,
the NETCONF server attempts to derive a NETCONF username from the
certificate presented by the NETCONF client. If the NETCONF server
cannot derive a valid NETCONF username from the client's presented
certificate, then the NETCONF server MUST close the TLS connection,
and MUST NOT accept NETCONF messages over it. The NETCONF server
uses one of the following algorithms to produce a NETCONF username
from the certificate presented by the NETCONF client:
o Map a certificate directly to a specified, pre-configured, NETCONF
username;
o Extract the subjectAltName's rfc822Name from the certificate, then
use the extracted rfc822Name as the NETCONF username;
o Extract the subjectAltName's dnsName from the certificate, then
use the extracted dnsName as the NETCONF username;
o Extract the subjectAltName's iPAddress from the certificate, then
use the extracted iPAddress as the NETCONF username;
o Examine the subjectAltName's rfc822Name, dnsName, and iPAddress
fields in a pre-defined order. Return the value from the first
subjectAltName field that is examined, defined, and populated with
a non-empty value. If no subjectAltName field of a specific type
is defined, then the examination skips that field and proceeds to
examine the next field type. If a subjectAltName field is
defined, but the value is not populated, or is populated by an
empty value, then the examination skips that field and proceeds to
examine the next field type.
The NETCONF server MUST implement all of these algorithms, and allow
the deployer to choose the algorithm used. The cert-map list in the
ietf-netconf-tls YANG module specifies how a NETCONF server
transforms a certificate into a NETCONF username.
If the fingerprint of locally held copy of a trusted CA certificate
is configured in the cert-map list in the ietf-netconf-tls YANG
module, and that CA certificate is used to validate the certificate
presented by the client, then the NETCONF server uses that cert-map
list entry to produce the NETCONF username. This allows multiple
client certificates (all signed by the same trusted CA certificate)
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to be mapped to a NETCONF username by a single entry in the cert-map
list.
3.2.2. Deriving NETCONF Usernames From PSK Identities
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 module, defined in Section 4.2, specifies
how a NETCONF server transforms a TLS pre-shared key into a NETCONF
username.
4. Data Model
4.1. Data Model Overview
The YANG module "ietf-netconf-tls", which defines configuration
parameters for mapping TLS parameters to NETCONF usernames, has the
following structure. Square brackets are used to enclose a list's
keys, and "?" means that the node is optional. Choice and case nodes
are enclosed in parenthesis, and a case node is marked with a colon
(":").
module: ietf-netconf-tls
+--rw netconf-tls
+--rw cert-maps
| +--rw cert-to-security-name [id]
| +--rw id uint32
| +--rw fingerprint tls-fingerprint
| +--rw map-type identityref
| +--rw cert-specified-security-name nacm:user-name-type
+--rw psk-maps
+--rw psk-map [psk-identity]
+--rw psk-identity string
+--rw user-name nacm:user-name-type
+--rw valid-not-before? yang:date-and-time
+--rw valid-not-after? yang:date-and-time
+--rw key string
4.2. YANG Module
The ietf-netconf-tls YANG module defines objects for remotely
configuring the mapping of TLS certficates and of PSK Identities to
NETCONF usernames.
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<CODE BEGINS> file "ietf-netconf-tls@2013-02-19.yang"
module ietf-netconf-tls {
namespace "urn:ietf:params:xml:ns:yang:ietf-netconf-tls";
prefix "nctls";
import ietf-yang-types {
prefix yang;
}
import ietf-netconf-acm {
prefix nacm;
}
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 applies to NETCONF over TLS. It specifies how
NETCONF servers transform X.509 certificates presented by clients
into NETCONF usernames. It also specifies how NETCONF servers
transform pre-shared TLS keys into NETCONF usernames.
The cert-maps container in this YANG module is patterned after
parts of the SNMP-TLS-TM-MIB defined in RFC 6353. Much of the
description text has been copied directly from the
SNMP-TLS-TM-MIB, and modified as necessary.
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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 "2013-02-19" {
description
"Initial version";
reference
"RFC XXXX: NETCONF over Transport Layer Security (TLS)";
}
feature map-certificates {
description
"The map-certificates feature indicates that the server
implements mapping X.509 certificates to NETCONF user names.";
}
feature map-pre-shared-keys {
description
"The map-pre-shared-keys feature indicates that the server
implements mapping TLS pre-shared keys to NETCONF user names.";
}
// [DISCUSS] This definition of tls-fingerprint is the same as
// the one in draft-ietf-netmod-snmp-cfg-01.txt; can
// we avoid this duplication?
typedef tls-fingerprint {
type yang:hex-string {
pattern '([0-9a-fA-F]){2}(:([0-9a-fA-F]){2}){0,254}';
}
description
"A fingerprint value that can be used to uniquely reference
other data of potentially arbitrary length.
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An tls-fingerprint value is composed of a 1-octet hashing
algorithm identifier followed by the fingerprint value. The
octet value encoded is taken from the IANA TLS HashAlgorithm
Registry (RFC 5246). The remaining octets are filled using
the results of the hashing algorithm.
The corresponding TEXTUAL-CONVENTION allows a zero-length
value to be used for objects that are optional. In the YANG
data models, such objects are represented as optional leafs.";
reference "SNMP-TLS-TM-MIB.SnmpTLSFingerprint";
}
/* Identities */
// [DISCUSS] The definitions of identities is the same as
// the those in draft-ietf-netmod-snmp-cfg-01.txt; can
// we avoid this duplication?
identity cert-to-tm-security-name {
}
identity specified {
base cert-to-tm-security-name;
reference "SNMP-TLS-TM-MIB.snmpTlstmCertSpecified";
}
identity san-rfc822-name {
base cert-to-tm-security-name;
reference "SNMP-TLS-TM-MIB.snmpTlstmCertSANRFC822Name";
}
identity san-dns-name {
base cert-to-tm-security-name;
reference "SNMP-TLS-TM-MIB.snmpTlstmCertSANDNSName";
}
identity san-ip-address {
base cert-to-tm-security-name;
reference "SNMP-TLS-TM-MIB.snmpTlstmCertSANIpAddress";
}
identity san-any {
base cert-to-tm-security-name;
reference "SNMP-TLS-TM-MIB.snmpTlstmCertSANAny";
}
identity common-name {
base cert-to-tm-security-name;
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reference "SNMP-TLS-TM-MIB.snmpTlstmCertCommonName";
}
container netconf-tls {
// Objects related to deriving NETCONF usernames from X.509
// certificates.
container cert-maps {
if-feature map-certificates;
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.
On an incoming TLS connection, the client's presented
certificate MUST either be validated based on an established
trust anchor, or it MUST directly match a fingerprint in the
'cert-map' list. This module does not provide any mechanisms
for configuring the trust anchors; the transfer of any needed
trusted certificates for certificate chain validation is
expected to occur through an out-of-band transfer.
Once the certificate has been found acceptable (either by
certificate chain validation or directly matching a
fingerprint in the cert-map list), the cert-map list is
consulted to determine the appropriate NETCONF username to
associate with the remote connection. This is done by
considering each cert-to-security-name list entry in order.
The cert-to-security-name entry's fingerprint determines
whether the list entry is a match for the incoming
connection:
1) If the cert-to-security-name list entry's fingerprint
value matches that of the presented certificate, then
consider the list entry as a successful match.
2) If the cert-to-security-name list entry's fingerprint
value matches that of a locally held copy of a trusted CA
certificate, and that CA certificate was part of the CA
certificate chain to the presented certificate, then
consider the list entry as a successful match.
Once a matching cert-to-security-name list entry has been
found, the NETCONF server uses the map-type to determine how
the NETCONF username associated with the session should be
determined. See the map-type leaf's description for details
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on determining the NETCONF username value. If it is
impossible to determine a NETCONF username from the
cert-to-security-name list entry's data combined with the
data presented in the certificate, then additional
cert-to-tm-security-name list entries MUST be searched
looking for another potential match. If a resulting
NETCONF username mapped from a given cert-to-security-name
list entry is not compatible with the needed requirements
of a NETCONF username, then it MUST be considered an invalid
match and additional cert-to-security-name list entries MUST
be searched looking for another potential match.
If no matching and valid cert-to-security-name list entry can
be found, then the NETCONF server MUST close the connection,
and MUST NOT accept NETCONF messages over it.
Security administrators are encouraged to make use of
certificates with subjectAltName fields that can be used as
NETCONF usernames so that a single root CA certificate can
allow all child certificate's subjectAltName to map directly
to a NETCONF usernames via a 1:1 transformation.";
list cert-to-security-name {
key id;
description
"This list defines how certificates are mapped to
security names.";
reference "SNMP-TLS-TM-MIB.snmpTlstmCertToTSNEntry";
leaf id {
type uint32;
description
"The id specifies the order in which the entries in the
cert-to-security-name container are searched. Entries
with lower numbers are searched first.";
reference "SNMP-TLS-TM-MIB.snmpTlstmCertToTSNID";
}
leaf fingerprint {
type tls-fingerprint;
mandatory true;
description
"Specifies a value with which the fingerprint of the
certificate presented by the peer is compared. If the
fingerprint of the certificate presented by the peer does
not match the fingerprint configured, then the entry is
skipped and the search for a match continues.";
reference "SNMP-TLS-TM-MIB.snmpTlstmCertToTSNFingerprint";
}
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leaf map-type {
type identityref {
base cert-to-tm-security-name;
}
mandatory true;
description
"Specifies the algorithm used to map the certificate
presented by the peer to the NETCONF username.
Mappings that use the snmpTlstmCertToTSNData column
need to augment the 'cert-to-tm-security-name' list
with additional configuration objects corresponding
to the snmpTlstmCertToTSNData value. Such objects
should use the 'when' statement to make them
conditional based on the 'map-type'.";
reference "SNMP-TLS-TM-MIB.snmpTlstmCertToTSNMapType";
}
leaf cert-specified-security-name {
when "../map-type = 'snmp:specified'";
type nacm:user-name-type;
mandatory true;
description
"Directly specifies the NETCONF username when the
'map-type' is 'specified'.";
reference "SNMP-TLS-TM-MIB.snmpTlstmCertToTSNData";
}
} // list cert-to-security-name
} // container cert-maps
// Objects related to deriving NETCONF usernames from TLS
// pre-shared keys.
container psk-maps {
if-feature 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 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)";
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list psk-map {
key psk-identity;
leaf psk-identity {
type string;
description
"The PSK identity encoded as a UTF-8 string. For details on
how the PSK identity MAY 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 valid-not-before {
type yang:date-and-time;
description
"This PSK identity is not valid before the given data
and time.";
}
leaf valid-not-after {
type yang:date-and-time;
description
"This PSK identity is not valid before the given date
and time.";
}
leaf key {
type string {
pattern '([0-9a-fA-F]){2}(:([0-9a-fA-F]){2})*';
}
mandatory true;
nacm:default-deny-all;
description
"The key associated with the PSK identity";
}
} // list psk-map
} // container psk-maps
} // container netconf-tls
}
<CODE ENDS>
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5. Usage Examples
5.1. Certificate Mapping Configuration Example
The following XML shows an example of parameters for mapping an X.509
certificate to a NETCONF username:
<netconf-tls
xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-tls">
<cert-maps>
<cert-to-security-name>
<id>10</id>
<fingerprint>de:ad:be:ef</fingerprint> <!-- Not valid -->
<map-type>specified</map-type>
<cert-specified-security-name>
admin
</cert-specified-security-name>
</cert-to-security-name>
</cert-maps>
</netconf-tls>
5.2. PSK Mapping Configuration Example
The following XML shows an example of parameters for mapping a pre-
shared key to a NETCONF username:
<netconf-tls
xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-tls">
<psk-maps>
<psk-map>
<psk-identity>a8gc8]klh59</psk-identity>
<user-name>admin</user-name>
<valid-not-before>2013-01-01T00:00:00-00:00</valid-not-before>
<valid-not-after>2014-01-01T00:00:00-00:00</valid-not-after>
</psk-map>
</psk-maps>
</netconf-tls>
6. Security Considerations
The security considerations described throughout [RFC5246] and
[RFC6241] apply here as well.
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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
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 name "netconf-tls". This port will be the default
port for NETCONF over TLS, as defined in this document.
Registration Contact: Mohamad Badra, mbadra@gmail.com.
Transport Protocol: TCP.
Port Number: 6513
Broadcast, Multicast or Anycast: No.
Port Name: netconf-tls.
Service Name: netconf.
Reference: RFC 5539
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8. Acknowledgements
A significant amount of the text in Section 3 was lifted from
[RFC4642].
The author would like to acknowledge David Harrington, Miao Fuyou,
Eric Rescorla, Simon Josefsson, Olivier Coupelon, Alfred Hoenes, and
the NETCONF mailing list members for their comments on the document.
The author also appreciates Bert Wijnen, Mehmet Ersue, and Dan
Romascanu for their efforts on issues resolving discussion; and
Charlie Kaufman, Pasi Eronen, and Tim Polk for the thorough review of
previous versions of this document.
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
[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.
[RFC6125] Saint-Andre, P. and J. Hodges, "Representation and
Verification of Domain-Based Application Service Identity
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within Internet Public Key Infrastructure Using X.509
(PKIX) Certificates in the Context of Transport Layer
Security (TLS)", RFC 6125, March 2011.
[RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure
Shell (SSH)", RFC 6242, June 2011.
[RFC6353] Hardaker, W., "Transport Layer Security (TLS) Transport
Model for the Simple Network Management Protocol (SNMP)",
RFC 6353, July 2011.
10.2. Informative References
[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.
[RFC6241] Enns, R., Bjorklund, M., Schoenwaelder, J., and A.
Bierman, "Network Configuration Protocol (NETCONF)",
RFC 6241, June 2011.
Appendix A. Change Log (to be removed by RFC Editor before publication)
A.1. Open Issues
o The identities etc. have been essentially copied from the SNMP
configuration model. Are we really happy with this reuse by
copying? If so, do we keep the SNMP configuration model names or
adapt them to the NETCONF context?
o Right now, the YANG module focuses on the username mapping only.
There are certainly more configuration objects for the TLS
transport, e.g., which ports to listen on, which CERT to use etc.
o Shall we add support for call home, i.e., a device, after
initiating and establishing a TCP connection and executing the TLS
handshake, would switch role and subsequently act as a NETCONF
server. (This would likely also include new port numbers.)
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A.2. From draft-ietf-netconf-rfc5539bis-01 to
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.
o Clarified the document structure by promoting the sections of the
document related to the data model.
o Updated author's addresses.
A.3. From draft-badra-netconf-rfc5539bis-02 to
draft-ietf-netconf-rfc5539bis-00
o Remove the reference to BEEP
o rename host-part to domain-part in the description of RFC822.
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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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