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NETCONF over TLS 1.3
draft-ietf-netconf-over-tls13-01

Document Type Active Internet-Draft (netconf WG)
Authors Sean Turner , Russ Housley
Last updated 2023-01-09 (Latest revision 2022-10-24)
Replaces draft-turner-netconf-over-tls13
RFC stream Internet Engineering Task Force (IETF)
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draft-ietf-netconf-over-tls13-01
Network Configuration                                          S. Turner
Internet-Draft                                                     sn3rd
Intended status: Standards Track                              R. Housley
Expires: 27 April 2023                                    Vigil Security
                                                         24 October 2022

                          NETCONF over TLS 1.3
                    draft-ietf-netconf-over-tls13-01

Abstract

   RFC 7589 defines how to protect NETCONF messages with TLS 1.2.  This
   document describes how to protect NETCONF messages with TLS 1.3.

About This Document

   This note is to be removed before publishing as an RFC.

   The latest revision of this draft can be found at https://netconf-
   wg.github.io/netconf-over-tls13/draft-ietf-netconf-over-tls13.html.
   Status information for this document may be found at
   https://datatracker.ietf.org/doc/draft-ietf-netconf-over-tls13/.

   Discussion of this document takes place on the Network Configuration
   Working Group mailing list (mailto:netconf@ietf.org), which is
   archived at https://mailarchive.ietf.org/arch/browse/netconf/.
   Subscribe at https://www.ietf.org/mailman/listinfo/netconf/.

   Source for this draft and an issue tracker can be found at
   https://github.com/netconf-wg/netconf-over-tls13.

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 https://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 27 April 2023.

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Copyright Notice

   Copyright (c) 2022 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 (https://trustee.ietf.org/
   license-info) in effect on the date of publication of this document.
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.  Code Components
   extracted from this document must include Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions and Definitions . . . . . . . . . . . . . . . . .   2
   3.  Early Data  . . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Cipher Suites . . . . . . . . . . . . . . . . . . . . . . . .   3
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   5
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   5
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   5
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   6
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .   6
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Introduction

   [RFC7589] defines how to protect NETCONF messages [RFC6241] with TLS
   1.2 [RFC5246].  This document describes defines how to protect
   NETCONF messages with TLS 1.3 [I-D.ietf-tls-rfc8446bis].

   This document addresses cipher suites and the use of early data,
   which is also known as 0-RTT data.  It also updates the "netconf-tls"
   IANA Registered Port Number entry to refer to this document.  All
   other provisions set forth in [RFC7589] are unchanged, including
   connection initiation, message framing, connection closure,
   certificate validation, server identity, and client identity.

2.  Conventions and Definitions

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in
   BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

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3.  Early Data

   Early data (aka 0-RTT data) is a mechanism defined in TLS 1.3
   [I-D.ietf-tls-rfc8446bis] that allows a client to send data ("early
   data") as part of the first flight of messages to a server.  Note
   that TLS 1.3 can be used without early data as per Appendix F.5 of
   [I-D.ietf-tls-rfc8446bis].  In fact, early data is permitted by TLS
   1.3 only when the client and server share a Pre-Shared Key (PSK),
   either obtained externally or via a previous handshake.  The client
   uses the PSK to authenticate the server and to encrypt the early
   data.

   As noted in Section 2.3 of [I-D.ietf-tls-rfc8446bis], the security
   properties for early data are weaker than those for subsequent TLS-
   protected data.  In particular, early data is not forward secret, and
   there is no protection against the replay of early data between
   connections.  Appendix E.5 of [I-D.ietf-tls-rfc8446bis] requires
   applications not use early data without a profile that defines its
   use.  This document specifies that NETCONF implementations that
   support TLS 1.3 MUST NOT use early data.

4.  Cipher Suites

   Implementations that support TLS 1.3 [I-D.ietf-tls-rfc8446bis] are
   REQUIRED to support the mandatory-to-implement cipher suites listed
   in Section 9.1 of [I-D.ietf-tls-rfc8446bis].

   Implementations that support TLS 1.3 MAY implement additional TLS
   cipher suites that provide mutual authentication and confidentiality,
   which are required for NETCONF [RFC6241].

   NETCONF implementations SHOULD follow the recommendations given in
   [I-D.ietf-uta-rfc7525bis].

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 So, this is what {{Section 9.1 of I-D.ietf-tls-rfc8446bis}} says:

   A TLS-compliant application MUST implement the TLS_AES_128_GCM_SHA256
   [GCM] cipher suite and SHOULD implement the TLS_AES_256_GCM_SHA384
   [GCM] and TLS_CHACHA20_POLY1305_SHA256 [RFC8439] cipher suites (see
   Appendix B.4).

   A TLS-compliant application MUST support digital signatures with
   rsa_pkcs1_sha256 (for certificates), rsa_pss_rsae_sha256 (for
   CertificateVerify and certificates), and ecdsa_secp256r1_sha256.  A
   TLS-compliant application MUST support key exchange with secp256r1
   (NIST P-256) and SHOULD support key exchange with X25519 [RFC7748].

 Is there any reason to narrow the algorithm choices?

 My guess is not.  These ought to be available in all TLS libraries.

5.  Security Considerations

   Please review the Security Considerations in TLS 1.3
   [I-D.ietf-tls-rfc8446bis].

   Please review the recommendations regarding Diffie-Hellman exponent
   reuse in Section 7.4 of [I-D.ietf-uta-rfc7525bis].

   Please review the Security Considerations in NETCONF [RFC6241].

   NETCONF is used to access configuration and state information and to
   modify configuration information.  TLS 1.3 mutual authentication is
   used to ensure that only authorized users and systems are able to
   view the NETCONF server's configuration and state or to modify the
   NETCONF server's configuration.  To this end, neither the client nor
   the server should establish a NETCONF over TLS 1.3 connection with an
   unknown, unexpected, or incorrectly identified peer; see Section 7 of
   [RFC7589].  If deployments make use of a trusted list of
   Certification Authority (CA) certificates [RFC5280], then the listed
   CAs should only issue certificates to parties that are authorized to
   access the NETCONF servers.  Doing otherwise will allow certificates
   that were issued for other purposes to be inappropriately accepted by
   a NETCONF server.

   Please review [RFC6125] for further details on generic host name
   validation in the TLS context.

   Please review the recommendations regarding certificate revocation
   checking in Section 7.5 of [I-D.ietf-uta-rfc7525bis].

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6.  IANA Considerations

   IANA is requested to add a reference to this document in the
   "netconf-tls" entry in the "Registered Port Numbers".  The updated
   registry entry would appear as follows:

    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 7589, [THIS RFC]
    Port Number:            6513

7.  References

7.1.  Normative References

   [I-D.ietf-tls-rfc8446bis]
              Rescorla, E., "The Transport Layer Security (TLS) Protocol
              Version 1.3", Work in Progress, Internet-Draft, draft-
              ietf-tls-rfc8446bis-04, 7 March 2022,
              <https://datatracker.ietf.org/doc/html/draft-ietf-tls-
              rfc8446bis-04>.

   [I-D.ietf-uta-rfc7525bis]
              Sheffer, Y., Saint-Andre, P., and T. Fossati,
              "Recommendations for Secure Use of Transport Layer
              Security (TLS) and Datagram Transport Layer Security
              (DTLS)", Work in Progress, Internet-Draft, draft-ietf-uta-
              rfc7525bis-11, 16 August 2022,
              <https://datatracker.ietf.org/doc/html/draft-ietf-uta-
              rfc7525bis-11>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/rfc/rfc2119>.

   [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, DOI 10.17487/RFC5280, May 2008,
              <https://www.rfc-editor.org/rfc/rfc5280>.

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   [RFC6241]  Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
              and A. Bierman, Ed., "Network Configuration Protocol
              (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
              <https://www.rfc-editor.org/rfc/rfc6241>.

   [RFC7589]  Badra, M., Luchuk, A., and J. Schoenwaelder, "Using the
              NETCONF Protocol over Transport Layer Security (TLS) with
              Mutual X.509 Authentication", RFC 7589,
              DOI 10.17487/RFC7589, June 2015,
              <https://www.rfc-editor.org/rfc/rfc7589>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/rfc/rfc8174>.

7.2.  Informative References

   [RFC5246]  Dierks, T. and E. Rescorla, "The Transport Layer Security
              (TLS) Protocol Version 1.2", RFC 5246,
              DOI 10.17487/RFC5246, August 2008,
              <https://www.rfc-editor.org/rfc/rfc5246>.

   [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
              Security (TLS)", RFC 6125, DOI 10.17487/RFC6125, March
              2011, <https://www.rfc-editor.org/rfc/rfc6125>.

Acknowledgments

   We would like to thank the following people TBD.

Authors' Addresses

   Sean Turner
   sn3rd
   Email: sean@sn3rd.com

   Russ Housley
   Vigil Security, LLC
   516 Dranesville Road
   Herndon, VA,  20170
   United States of America
   Email: housley@vigilsec.com

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