draft-ietf-netconf-tls-07.txt   rfc5539.txt 
NETCONF Working Group M. Badra Network Working Group M. Badra
Internet-Draft CNRS/LIMOS Laboratory Request for Comments: 5539 CNRS/LIMOS Laboratory
Intended status: Standards Track February 24, 2009 NETCONF over Transport Layer Security (TLS)
Expires: August 28, 2009
NETCONF Over Transport Layer Security (TLS)
draft-ietf-netconf-tls-07.txt
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and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice Copyright Notice
Copyright (c) 2009 IETF Trust and the persons identified as the Copyright (c) 2009 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents in effect on the date of Provisions Relating to IETF Documents in effect on the date of
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Please review these documents carefully, as they describe your rights Please review these documents carefully, as they describe your rights
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Abstract Abstract
The Network Configuration Protocol (NETCONF) provides mechanisms to The Network Configuration Protocol (NETCONF) provides mechanisms to
install, manipulate, and delete the configuration of network devices. install, manipulate, and delete the configuration of network devices.
This document describes how to use the Transport Layer Security (TLS) This document describes how to use the Transport Layer Security (TLS)
protocol to secure NETCONF exchanges. protocol to secure NETCONF exchanges.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Conventions Used in this Document . . . . . . . . . . . . . 3 1.1. Conventions Used in This Document . . . . . . . . . . . . . 2
2. NETCONF over TLS . . . . . . . . . . . . . . . . . . . . . . . 3 2. NETCONF over TLS . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Connection Initiation . . . . . . . . . . . . . . . . . . . 3 2.1. Connection Initiation . . . . . . . . . . . . . . . . . . . 3
2.2. Connection Closure . . . . . . . . . . . . . . . . . . . . 4 2.2. Connection Closure . . . . . . . . . . . . . . . . . . . . 4
3. Endpoint Authentication and Identification . . . . . . . . . . 5 3. Endpoint Authentication and Identification . . . . . . . . . . 4
3.1. Server Identity . . . . . . . . . . . . . . . . . . . . . . 5 3.1. Server Identity . . . . . . . . . . . . . . . . . . . . . . 4
3.2. Client Identity . . . . . . . . . . . . . . . . . . . . . . 6 3.2. Client Identity . . . . . . . . . . . . . . . . . . . . . . 5
4. Security Considerations . . . . . . . . . . . . . . . . . . . . 6 4. Security Considerations . . . . . . . . . . . . . . . . . . . . 5
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6
7. Contributor's Address . . . . . . . . . . . . . . . . . . . . . 7 7. Contributor's Address . . . . . . . . . . . . . . . . . . . . . 7
8. Normative References . . . . . . . . . . . . . . . . . . . . . 7 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Appendix A. Change Log (to be removed by RFC Editor before 8.1. Normative References . . . . . . . . . . . . . . . . . . . 7
publication) . . . . . . . . . . . . . . . . . . . . . 8 8.2. Informative References . . . . . . . . . . . . . . . . . . 7
A.1. 06-07 . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
A.2. 05-06 . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
A.3. 04-05 . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction 1. Introduction
The NETCONF protocol [RFC4741] defines a mechanism through which a The NETCONF protocol [RFC4741] defines a mechanism through which a
network device can be managed. NETCONF is connection-oriented, network device can be managed. NETCONF is connection-oriented,
requiring a persistent connection between peers. This connection requiring a persistent connection between peers. This connection
must provide reliable, sequenced data delivery, integrity and must provide integrity, confidentiality, peer authentication, and
confidentiality and peers authentication. reliable, sequenced data delivery.
This document defines "NETCONF over TLS", which includes support for This document defines "NETCONF over TLS", which includes support for
certificate-based mutual authentication and key derivation, utilizing certificate-based mutual authentication and key derivation, utilizing
the protected ciphersuite negotiation, mutual authentication and key the protected ciphersuite negotiation, mutual authentication, and key
management capabilities of the TLS (Transport Layer Security) management capabilities of the TLS (Transport Layer Security)
protocol, described in [RFC5246]. protocol, described in [RFC5246].
Throughout this document, the terms "client" and "server" are used to Throughout this document, the terms "client" and "server" are used to
refer to the two ends of the TLS connection. The client actively refer to the two ends of the TLS connection. The client actively
opens the TLS connection, and the server passively listens for the opens the TLS connection, and the server passively listens for the
incoming TLS connection. The terms "manager" and "agent" are used to incoming TLS connection. The terms "manager" and "agent" are used to
refer to the two ends of the NETCONF protocol session. The manager refer to the two ends of the NETCONF protocol session. The manager
issues NETCONF remote procedure call (RPC) commands, and the agent issues NETCONF remote procedure call (RPC) commands, and the agent
replies to those commands. When NETCONF is run over TLS using the replies to those commands. When NETCONF is run over TLS using the
mapping defined in this document, the client is always the manager, mapping defined in this document, the client is always the manager,
and the server is always the agent. and the server is always the agent.
1.1. Conventions Used in this Document 1.1. Conventions Used in This Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
2. NETCONF over TLS 2. NETCONF over TLS
Since TLS is application protocol-independent, NETCONF can operate on Since TLS is application-protocol-independent, NETCONF can operate on
top of the TLS protocol transparently. This document defines how top of the TLS protocol transparently. This document defines how
NETCONF can be used within a TLS session. NETCONF can be used within a TLS session.
2.1. Connection Initiation 2.1. Connection Initiation
The peer acting as the NETCONF manager MUST also act as the TLS The peer acting as the NETCONF manager MUST also act as the TLS
client. It MUST connect to the server that passively listens for the client. It MUST connect to the server that passively listens for the
incoming TLS connection on the TCP port <IANA-to-be-assigned>. (Note incoming TLS connection on the TCP port 6513. It MUST therefore send
to RFC Editor: please replace <IANA-to-be-assigned> with the IANA- the TLS ClientHello message to begin the TLS handshake. Once the TLS
assigned value, and remove this note). It 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 handshake has finished, the client and the server MAY begin to
exchange NETCONF data. In particular, the client will send complete exchange NETCONF data. In particular, the client will send complete
XML documents to the server containing <rpc> elements, and the server XML documents to the server containing <rpc> elements, and the server
will respond with complete XML documents containing <rpc-reply> will respond with complete XML documents containing <rpc-reply>
elements. The client MAY indicate interest in receiving event elements. The client MAY indicate interest in receiving event
notifications from a server by creating a subscription to receive notifications from a server by creating a subscription to receive
event notifications [RFC5277], in which case the server replies to event notifications [RFC5277]. In this case, the server replies to
indicate whether the subscription request was successful and, if it indicate whether the subscription request was successful and, if it
was successful, begins sending the event notifications to the client was successful, the server begins sending the event notifications to
as the events occur within the system. the client as the events occur within the system.
All NETCONF messages MUST be sent as TLS "application data". It is All NETCONF messages MUST be sent as TLS "application data". It is
possible that multiple NETCONF messages be contained in one TLS possible that multiple NETCONF messages be contained in one TLS
record, or that a NETCONF message be transferred in multiple TLS record, or that a NETCONF message be transferred in multiple TLS
records. records.
This document uses the same delimiter sequence ("]]>]]>") defined in This document uses the same delimiter sequence ("]]>]]>") defined in
[RFC4742], which MUST be sent by both the client and the server after [RFC4742], which MUST be sent by both the client and the server after
each XML document in the NETCONF exchange. Since this character each XML document in the NETCONF exchange. Since this character
sequence can legally appear in plain XML in attribute values, sequence can legally appear in plain XML in attribute values,
comments, and processing instructions, implementations of this comments, and processing instructions, implementations of this
document MUST ensure that this character sequence is never part of a document MUST ensure that this character sequence is never part of a
NETCONF message. NETCONF message.
Implementation of the protocol specified in this document MAY Implementation of the protocol specified in this document MAY
implement any TLS cipher suite that provides certificate-based mutual implement any TLS cipher suite that provides certificate-based mutual
authentication [RFC5246]. authentication [RFC5246]. The server MUST support certificate-based
client authentication.
Implementations MUST support TLS 1.2 [RFC5246] and are REQUIRED to Implementations MUST support TLS 1.2 [RFC5246] and are REQUIRED to
support the mandatory to implement cipher suite, which is support the mandatory-to-implement cipher suite, which is
TLS_RSA_WITH_AES_128_CBC_SHA. This document is assumed to apply to 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 future versions of TLS; in which case, the mandatory-to-implement
cipher suite for the implemented version MUST be supported. cipher suite for the implemented version MUST be supported.
2.2. Connection Closure 2.2. Connection Closure
A TLS client (NETCONF manager) MUST close the associated TLS A TLS client (NETCONF manager) MUST close the associated TLS
connection if the connection is not expected to issue any NETCONF RPC connection if the connection is not expected to issue any NETCONF RPC
commands later. It MUST send a TLS close_notify alert before closing commands later. It MUST send a TLS close_notify alert before closing
the connection. The TLS client MAY choose to not wait for the TLS the connection. The TLS client MAY choose to not wait for the TLS
server (NETCONF agent) close_notify alert and simply close the server (NETCONF agent) close_notify alert and simply close the
connection, thus generating an incomplete close on the TLS server connection, thus generating an incomplete close on the TLS server
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connection. The close_notify's sender that is unprepared to receive connection. The close_notify's sender that is unprepared to receive
any more data MAY close the connection after sending the close_notify any more data MAY close the connection after sending the close_notify
alert, thus generating an incomplete close on the close_notify's alert, thus generating an incomplete close on the close_notify's
receiver side. receiver side.
3. Endpoint Authentication and Identification 3. Endpoint Authentication and Identification
3.1. Server Identity 3.1. Server Identity
During the TLS negotiation, the client MUST carefully examine the During the TLS negotiation, the client MUST carefully examine the
certificate presented by the server to determine if it meets their certificate presented by the server to determine if it meets the
expectations. Particularly, the client MUST check its understanding client's expectations. Particularly, the client MUST check its
of the server hostname against the server's identity as presented in understanding of the server hostname against the server's identity as
the server Certificate message, in order to prevent man-in-the-middle presented in the server Certificate message, in order to prevent man-
attacks. in-the-middle attacks.
Matching is performed according to the rules below (following the Matching is performed according to the rules below (following the
example of [RFC4642]): example of [RFC4642]):
o The client MUST use the server hostname it used to open the o The client MUST use the server hostname it used to open the
connection (or the hostname specified in TLS "server_name" connection (or the hostname specified in the TLS "server_name"
extension [RFC5246]) as the value to compare against the server extension [RFC5246]) as the value to compare against the server
name as expressed in the server certificate. The client MUST NOT name as expressed in the server certificate. The client MUST NOT
use any form of the server hostname derived from an insecure use any form of the server hostname derived from an insecure
remote source (e.g., insecure DNS lookup). CNAME canonicalization remote source (e.g., insecure DNS lookup). CNAME canonicalization
is not done. is not done.
o If a subjectAltName extension of type dNSName is present in the o If a subjectAltName extension of type dNSName is present in the
certificate, it MUST be used as the source of the server's certificate, it MUST be used as the source of the server's
identity. identity.
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that algorithm with other validation methods that achieve equivalent that algorithm with other validation methods that achieve equivalent
levels of verification (such as comparing the server certificate levels of verification (such as comparing the server certificate
against a local store of already-verified certificates and identity against a local store of already-verified certificates and identity
bindings). bindings).
If the client has external information as to the expected identity of If the client has external information as to the expected identity of
the server, the hostname check MAY be omitted. the server, the hostname check MAY be omitted.
3.2. Client Identity 3.2. Client Identity
The server may have no external knowledge on client's identity and The server MUST verify the identity of the client with certificate-
identity checks might not be possible (unless the client has a based authentication according to local policy to ensure that the
certificate chain rooted in an appropriate CA). If a server has incoming client request is legitimate before any configuration or
knowledge on client's identity (typically from some source external state data is sent to or received from the client.
to NETCONF or TLS) it MUST check the identity as described above.
4. Security Considerations 4. Security Considerations
The security considerations described throughout [RFC5246] and The security considerations described throughout [RFC5246] and
[RFC4741] apply here as well. [RFC4741] apply here as well.
This document in its current version does not support third party This document in its current version does not support third-party
authentication due to the fact that TLS does not specify this way of authentication (e.g., backend Authentication, Authorization, and
authentication and that NETCONF depends on the transport protocol for Accounting (AAA) servers) due to the fact that TLS does not specify
the authentication service. If third party authentication is needed, this way of authentication and that NETCONF depends on the transport
BEEP or SSH transport can be used. protocol for the authentication service. If third-party
authentication is needed, BEEP or SSH transport can be used.
An attacker might be able to inject arbitrary NETCONF messages via An attacker might be able to inject arbitrary NETCONF messages via
some application that does not carefully check exchanged messages or some application that does not carefully check exchanged messages or
deliberately insert the delimiter sequence in a NETCONF message to deliberately insert the delimiter sequence in a NETCONF message to
create a DoS attack. Hence, applications and NETCONF APIs MUST create a DoS attack. Hence, applications and NETCONF APIs MUST
ensure that the delimiter sequence defined in Section 2.1 never ensure that the delimiter sequence defined in Section 2.1 never
appears in NETCONF messages; otherwise, those messages can be appears in NETCONF messages; otherwise, those messages can be
dropped, garbled or mis-interpreted. If the delimiter sequence is dropped, garbled, or misinterpreted. If the delimiter sequence is
found in a NETCONF message by the sender side, a robust found in a NETCONF message by the sender side, a robust
implementation of this document should warn the user that illegal implementation of this document should warn the user that illegal
characters have been discovered. If the delimiter sequence is found characters have been discovered. If the delimiter sequence is found
in a NETCONF message by the receiver side (including any XML in a NETCONF message by the receiver side (including any XML
attribute values, XML comments or processing instructions) a robust attribute values, XML comments, or processing instructions), a robust
implementation of this document must silently discard the message implementation of this document must silently discard the message
without further processing and then stop the NETCONF session. without further processing and then stop the NETCONF session.
Finally, this document does not introduce any new security Finally, this document does not introduce any new security
considerations compared to [RFC4742]. considerations compared to [RFC4742].
5. IANA Considerations 5. IANA Considerations
IANA is requested to assign a TCP port number in the "Registered Port IANA has assigned a TCP port number (6513) in the "Registered Port
Numbers" range with the name "netconf-tls". This port will be the Numbers" range with the name "netconf-tls". This port will be the
default port for NETCONF over TLS, as defined in this document. default port for NETCONF over TLS, as defined in this document.
Registration Contact: Mohamad Badra, badra@isima.fr. Registration Contact: Mohamad Badra, badra@isima.fr.
Transport Protocol: TCP. Transport Protocol: TCP.
Port Number: TBA-by-IANA (if possible, please assign 6513). Port Number: 6513
Broadcast, Multicast or Anycast: No. Broadcast, Multicast or Anycast: No.
Port Name: netconf-tls. Port Name: netconf-tls.
Service Name: netconf. Service Name: netconf.
Reference: draft-ietf-netconf-tls-07. Reference: RFC 5539
6. Acknowledgements 6. Acknowledgements
A significant amount of the text in Section 3 was lifted from A significant amount of the text in Section 3 was lifted from
[RFC4642]. [RFC4642].
The author would like to acknowledge David Harrington, Miao Fuyou, The author would like to acknowledge David Harrington, Miao Fuyou,
Eric Rescorla, Juergen Schoenwaelder, Simon Josefsson, Olivier Eric Rescorla, Juergen Schoenwaelder, Simon Josefsson, Olivier
Coupelon, Alfred Hoenes and the NETCONF mailing list members for Coupelon, Alfred Hoenes, and the NETCONF mailing list members for
their comments on the document. The author appreciates also Bert their comments on the document. The author also appreciates Bert
Wijnen, Mehmet Ersue and Dan Romascanu for their efforts on issues Wijnen, Mehmet Ersue, and Dan Romascanu for their efforts on issues
resolving discussion, and Charlie Kaufman, Pasi Eronen and Tim Polk resolving discussion; and Charlie Kaufman, Pasi Eronen, and Tim Polk
for the thorough review of this document. for the thorough review of this document.
7. Contributor's Address 7. Contributor's Address
Ibrahim Hajjeh Ibrahim Hajjeh
Ineovation Ineovation
France France
E-mail: ibrahim.hajjeh@ineovation.fr EMail: ibrahim.hajjeh@ineovation.fr
8. Normative References 8. References
8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4642] Murchison, K., Vinocur, J., and C. Newman, "Using
Transport Layer Security (TLS) with Network News Transfer
Protocol (NNTP)", RFC 4642, October 2006.
[RFC4741] Enns, R., "NETCONF Configuration Protocol", RFC 4741, [RFC4741] Enns, R., "NETCONF Configuration Protocol", RFC 4741,
December 2006. December 2006.
[RFC4742] Wasserman, M. and T. Goddard, "Using the NETCONF [RFC4742] Wasserman, M. and T. Goddard, "Using the NETCONF
Configuration Protocol over Secure SHell (SSH)", RFC 4742, Configuration Protocol over Secure SHell (SSH)", RFC 4742,
December 2006. December 2006.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246, August 2008. (TLS) Protocol Version 1.2", RFC 5246, August 2008.
[RFC5277] Chisholm, S. and H. Trevino, "NETCONF Event
Notifications", RFC 5277, July 2008.
[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S., [RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
Housley, R., and W. Polk, "Internet X.509 Public Key Housley, R., and W. Polk, "Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 5280, May 2008. (CRL) Profile", RFC 5280, May 2008.
Appendix A. Change Log (to be removed by RFC Editor before publication) 8.2. Informative References
A.1. 06-07
New trust boilerplate introduced.
Section 2.1: reworded the text related to the delimiter sequence and
highlighted that implementations MUST ensure that delimiter sequence
is never part of a NETCONF message.
Section 2.2: Obselete RFC4366 is replaced with RFC5246.
Section 2.2: s/to issues any NETCONF commands/to issue any NETCONF
commands/
Section 3.2: "Typically, the server has no external knowledge" is
replaced with "The server may have no external knowledge"
Section 4 : text added to the Security Considerations section to
describe security threads and to give recommendations on the sender
and receiver behaviour in case they detect the delimiter sequence in
between a NETCONF message.
A.2. 05-06
Section 5 (IANA Considerations Section): "Anycast" is replaced with
"No".
A.3. 04-05
Removed any text related to PSK based authentication.
Revised to TLS with certificate-based mutual authentication.
Removed Cipher Suite Requirements section which was redundant with
TLS.
Added small clarifications to the "Introduction" and "Endpoint
Authentication and Identification" sections.
Section 2.1: Included mandatory to implement cipher suites that
track future versions of the TLS.
Section 2.2: Revised the connection closure session with regards to
TLS 1.2.
Section 5: Revised to help IANA with the port assignment. [RFC4642] Murchison, K., Vinocur, J., and C. Newman, "Using
Transport Layer Security (TLS) with Network News Transfer
Protocol (NNTP)", RFC 4642, October 2006.
Section 8: Removed RFC4086 and RFC4279 from the reference section [RFC5277] Chisholm, S. and H. Trevino, "NETCONF Event
Notifications", RFC 5277, July 2008.
Author's Address Author's Address
Mohamad Badra Mohamad Badra
CNRS/LIMOS Laboratory CNRS/LIMOS Laboratory
Campus de cezeaux, Bat. ISIMA Campus de cezeaux, Bat. ISIMA
Aubiere, 63170 Aubiere 63170
Fance France
Email: badra@isima.fr EMail: badra@isima.fr
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