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Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Outdated reference: A later version (-11) exists of draft-ietf-uta-tls-bcp-08 ** Obsolete normative reference: RFC 5246 (Obsoleted by RFC 8446) ** Obsolete normative reference: RFC 6125 (Obsoleted by RFC 9525) -- Obsolete informational reference (is this intentional?): RFC 4742 (Obsoleted by RFC 6242) -- Obsolete informational reference (is this intentional?): RFC 5539 (Obsoleted by RFC 7589) Summary: 2 errors (**), 0 flaws (~~), 2 warnings (==), 3 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 NETCONF Working Group M. Badra 3 Internet-Draft Zayed University 4 Obsoletes: 5539 (if approved) A. Luchuk 5 Intended status: Standards Track SNMP Research, Inc. 6 Expires: July 31, 2015 J. Schoenwaelder 7 Jacobs University Bremen 8 January 27, 2015 10 Using the NETCONF Protocol over Transport Layer Security (TLS) with 11 Mutual X.509 Authentication 12 draft-ietf-netconf-rfc5539bis-08 14 Abstract 16 The Network Configuration Protocol (NETCONF) provides mechanisms to 17 install, manipulate, and delete the configuration of network devices. 18 This document describes how to use the Transport Layer Security (TLS) 19 protocol with mutual X.509 authentication to secure the exchange of 20 NETCONF messages. This revision of RFC 5539 documents the new 21 message framing used by NETCONF 1.1 and it obsoletes RFC 5539. 23 Status of This Memo 25 This Internet-Draft is submitted in full conformance with the 26 provisions of BCP 78 and BCP 79. 28 Internet-Drafts are working documents of the Internet Engineering 29 Task Force (IETF). Note that other groups may also distribute 30 working documents as Internet-Drafts. The list of current Internet- 31 Drafts is at http://datatracker.ietf.org/drafts/current/. 33 Internet-Drafts are draft documents valid for a maximum of six months 34 and may be updated, replaced, or obsoleted by other documents at any 35 time. It is inappropriate to use Internet-Drafts as reference 36 material or to cite them other than as "work in progress." 38 This Internet-Draft will expire on July 31, 2015. 40 Copyright Notice 42 Copyright (c) 2015 IETF Trust and the persons identified as the 43 document authors. All rights reserved. 45 This document is subject to BCP 78 and the IETF Trust's Legal 46 Provisions Relating to IETF Documents 47 (http://trustee.ietf.org/license-info) in effect on the date of 48 publication of this document. Please review these documents 49 carefully, as they describe your rights and restrictions with respect 50 to this document. Code Components extracted from this document must 51 include Simplified BSD License text as described in Section 4.e of 52 the Trust Legal Provisions and are provided without warranty as 53 described in the Simplified BSD License. 55 Table of Contents 57 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 58 2. Connection Initiation . . . . . . . . . . . . . . . . . . . . 3 59 3. Message Framing . . . . . . . . . . . . . . . . . . . . . . . 3 60 4. Connection Closure . . . . . . . . . . . . . . . . . . . . . 3 61 5. Certificate Validation . . . . . . . . . . . . . . . . . . . 4 62 6. Server Identity . . . . . . . . . . . . . . . . . . . . . . . 4 63 7. Client Identity . . . . . . . . . . . . . . . . . . . . . . . 4 64 8. Cipher Suites . . . . . . . . . . . . . . . . . . . . . . . . 5 65 9. Security Considerations . . . . . . . . . . . . . . . . . . . 5 66 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 67 11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7 68 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 7 69 12.1. Normative References . . . . . . . . . . . . . . . . . . 7 70 12.2. Informative References . . . . . . . . . . . . . . . . . 8 71 Appendix A. Changes from RFC 5539 . . . . . . . . . . . . . . . 8 72 Appendix B. Change Log . . . . . . . . . . . . . . . . . . . . . 8 73 B.1. draft-ietf-netconf-rfc5539bis-07 . . . . . . . . . . . . 8 74 B.2. draft-ietf-netconf-rfc5539bis-06 . . . . . . . . . . . . 9 75 B.3. draft-ietf-netconf-rfc5539bis-05 . . . . . . . . . . . . 9 76 B.4. draft-ietf-netconf-rfc5539bis-04 . . . . . . . . . . . . 9 77 B.5. draft-ietf-netconf-rfc5539bis-03 . . . . . . . . . . . . 9 78 B.6. draft-ietf-netconf-rfc5539bis-02 . . . . . . . . . . . . 9 79 B.7. draft-ietf-netconf-rfc5539bis-00 . . . . . . . . . . . . 10 80 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10 82 1. Introduction 84 The NETCONF protocol [RFC6241] defines a mechanism through which a 85 network device can be managed. NETCONF is connection-oriented, 86 requiring a persistent connection between peers. This connection 87 must provide integrity, confidentiality, peer authentication, and 88 reliable, sequenced data delivery. 90 This document defines how NETCONF messages can be exchanged over 91 Transport Layer Security (TLS) [RFC5246]. Implementations MUST 92 support mutual TLS certificate-based authentication [RFC5246]. This 93 assures the NETCONF server of the identity of the principal who 94 wishes to manipulate the management information. It also assures the 95 NETCONF client of the identity of the server for which it wishes to 96 manipulate the management information. 98 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 99 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 100 document are to be interpreted as described in [RFC2119]. 102 2. Connection Initiation 104 The peer acting as the NETCONF client MUST act as the TLS client. 105 The TLS client actively opens the TLS connection and the TLS server 106 passively listens for the incoming TLS connections. The well-known 107 TCP port number 6513 is used by NETCONF servers to listen for TCP 108 connections established by NETCONF over TLS clients. The TLS client 109 MUST send the TLS ClientHello message to begin the TLS handshake. 110 Once the TLS handshake has finished, the client and the server MAY 111 begin to exchange NETCONF messages. Client and server identity 112 verification is done before the NETCONF message is sent. 113 This means that the identity verification is completed before the 114 NETCONF session is started. 116 3. Message Framing 118 All NETCONF messages MUST be sent as TLS "application data". It is 119 possible that multiple NETCONF messages be contained in one TLS 120 record, or that a NETCONF message be transferred in multiple TLS 121 records. 123 The previous version [RFC5539] of this document used the framing 124 sequence defined in [RFC4742], under the assumption that it could not 125 be found in well-formed XML documents. However, this assumption is 126 not correct [RFC6242]. In order to solve this problem, this document 127 adopts the framing protocol defined in [RFC6242] as follows: 129 The NETCONF message MUST be followed by the character 130 sequence ]]>]]>. Upon reception of the message, the peers 131 inspect the announced capabilities. If the :base:1.1 capability is 132 advertised by both peers, the chunked framing mechanism defined in 133 Section 4.2 of [RFC6242] is used for the remainder of the NETCONF 134 session. Otherwise, the old end-of-message-based mechanism (see 135 Section 4.3 of [RFC6242]) is used. 137 4. Connection Closure 139 A NETCONF server will process NETCONF messages from the NETCONF 140 client in the order in which they are received. A NETCONF session is 141 closed using the operation. When the NETCONF server 142 processes a operation, the NETCONF server SHALL 143 respond and close the TLS session as described in Section 7.2.1 of 144 [RFC5246]. 146 5. Certificate Validation 148 Both peers MUST use X.509 certificate path validation [RFC5280] to 149 verify the integrity of the certificate presented by the peer. The 150 presented X.509 certificate may also be considered valid if it 151 matches a locally configured certificate fingerprint. If X.509 152 certificate path validation fails and the presented X.509 certificate 153 does not match a locally configured certificate fingerprint, the 154 connection MUST be terminated as defined in [RFC5246]. 156 6. Server Identity 158 The NETCONF client MUST check the identity of the server according to 159 Section 6 of [RFC6125]. 161 7. Client Identity 163 The NETCONF server MUST verify the identity of the NETCONF client to 164 ensure that the incoming request to establish a NETCONF session is 165 legitimate before the NETCONF session is started. 167 The NETCONF protocol [RFC6241] requires that the transport protocol's 168 authentication process results in an authenticated NETCONF client 169 identity whose permissions are known to the server. The 170 authenticated identity of a client is commonly referred to as the 171 NETCONF username. The following algorithm is used by the NETCONF 172 server to derive a NETCONF username from a certificate: 174 o The server maintains an ordered list of mappings of certificates 175 to NETCONF usernames. The username is derived by considering each 176 list entry in order. The fingerprint member of a list entry 177 determines whether the list entry is a match: 179 1. If the list entry's fingerprint value matches that of the 180 presented certificate, then consider the list entry as a 181 successful match. 183 2. If the list entry's fingerprint value matches that of a 184 locally held copy of a trusted CA certificate, and that CA 185 certificate was part of the CA certificate chain to the 186 presented certificate, then consider the list entry as a 187 successful match. 189 o Once a matching list entry has been found, the mapping type 190 property of the list entry is used to determine how the username 191 associated with the certificate should be determined. Possible 192 mapping options are: 194 A. The username is explicitly configured. 196 B. The subjectAltName's rfc822Name is mapped to a username. 198 C. The subjectAltName's dNSName is mapped to a username. 200 D. The subjectAltName's iPAddress is mapped to a username. 202 E. Any of the subjectAltName's rfc822Name, dNSName, iPAddress is 203 mapped to a username. 205 F. The certificate's CommonName is mapped to a username. 207 o If it is impossible to determine a username from the list entry's 208 data combined with the data presented in the certificate, then 209 additional list entries MUST be searched looking for another 210 potential match. Similarily, if the username does not comply to 211 the NETCONF requirements on usernames [RFC6241] (i.e., the 212 username is not representable in XML), then additional list 213 entries MUST be searched looking for another potential match. If 214 there are no further list entries, the TLS session MUST be 215 terminated. 217 The username provided by the NETCONF over TLS implementation will be 218 made available to the NETCONF message layer as the NETCONF username 219 without modification. 221 8. Cipher Suites 223 Implementations MUST support TLS 1.2 [RFC5246] and are REQUIRED to 224 support the mandatory-to-implement cipher suite. Implementations MAY 225 implement additional TLS cipher suites that provide mutual 226 authentication [RFC5246] and confidentiality as required by NETCONF 227 [RFC6241]. Implementations SHOULD follow the recommendations given 228 in [I-D.ietf-uta-tls-bcp]. 230 9. Security Considerations 232 NETCONF is used to access configuration and state information and to 233 modify configuration information, so the ability to access this 234 protocol should be limited to users and systems that are authorized 235 to view the NETCONF server's configuration and state or to modify the 236 NETCONF server's configuration. 238 Configuration or state data may include sensitive information, such 239 as usernames or security keys. So, NETCONF requires communications 240 channels that provide strong encryption for data privacy. This 241 document defines a NETCONF over TLS mapping that provides for support 242 of strong encryption and authentication. The security considerations 243 for TLS [RFC5246] and NETCONF [RFC6241] apply here as well. 245 NETCONF over TLS requires mutual authentication. Neither side should 246 establish a NETCONF over TLS connection with an unknown, unexpected, 247 or incorrect identity on the opposite side. This document does not 248 support third-party authentication (e.g., backend Authentication, 249 Authorization, and Accounting (AAA) servers) due to the fact that TLS 250 does not specify this way of authentication and that NETCONF depends 251 on the transport protocol for the authentication service. If third- 252 party authentication is needed, the SSH transport can be used. 254 RFC 5539 assumes that the end-of-message (EOM) sequence, ]]>]]>, 255 cannot appear in any well-formed XML document, which turned out to be 256 mistaken. The EOM sequence can cause operational problems and open 257 space for attacks if sent deliberately in NETCONF messages. It is 258 however believed that the associated threat is not very high. This 259 document still uses the EOM sequence for the initial message 260 to avoid incompatibility with existing implementations. When both 261 peers implement :base:1.1 capability, a proper framing protocol 262 (chunked framing mechanism; see Section 3) is used for the rest of 263 the NETCONF session, to avoid injection attacks. 265 10. IANA Considerations 267 Based on the previous version of this document, RFC 5539, IANA has 268 assigned a TCP port number (6513) in the "Registered Port Numbers" 269 range with the service name "netconf-tls". This port will be the 270 default port for NETCONF over TLS, as defined in Section 2. Below is 271 the registration template following the rules in [RFC6335]. 273 Service Name: netconf-tls 274 Transport Protocol(s): TCP 275 Assignee: IESG 276 Contact: IETF Chair 277 Description: NETCONF over TLS 278 Reference: RFC XXXX 279 Port Number: 6513 281 [[CREF1: RFC Editor: Please replace XXXX above with the allocated RFC 282 number and remove this comment. --JS]] 284 11. Acknowledgements 286 The authors like to acknowledge Martin Bjorklund, Olivier Coupelon, 287 Mehmet Ersue, Miao Fuyou, Ibrahim Hajjeh, David Harrington, Alfred 288 Hoenes, Simon Josefsson, Tom Petch, Eric Rescorla, Dan Romascanu, 289 Kent Watsen, Bert Wijnen and the NETCONF mailing list members for 290 their comments on this document. Charlie Kaufman, Pasi Eronen, and 291 Tim Polk provided a thorough review of previous versions of this 292 document. 294 Juergen Schoenwaelder was partly funded by Flamingo, a Network of 295 Excellence project (ICT-318488) supported by the European Commission 296 under its Seventh Framework Programme. 298 12. References 300 12.1. Normative References 302 [I-D.ietf-uta-tls-bcp] 303 Sheffer, Y., Holz, R., and P. Saint-Andre, 304 "Recommendations for Secure Use of TLS and DTLS", draft- 305 ietf-uta-tls-bcp-08 (work in progress), December 2014. 307 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 308 Requirement Levels", BCP 14, RFC 2119, March 1997. 310 [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security 311 (TLS) Protocol Version 1.2", RFC 5246, August 2008. 313 [RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S., 314 Housley, R., and W. Polk, "Internet X.509 Public Key 315 Infrastructure Certificate and Certificate Revocation List 316 (CRL) Profile", RFC 5280, May 2008. 318 [RFC6125] Saint-Andre, P. and J. Hodges, "Representation and 319 Verification of Domain-Based Application Service Identity 320 within Internet Public Key Infrastructure Using X.509 321 (PKIX) Certificates in the Context of Transport Layer 322 Security (TLS)", RFC 6125, March 2011. 324 [RFC6241] Enns, R., Bjorklund, M., Schoenwaelder, J., and A. 325 Bierman, "Network Configuration Protocol (NETCONF)", RFC 326 6241, June 2011. 328 [RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure 329 Shell (SSH)", RFC 6242, June 2011. 331 [RFC6335] Cotton, M., Eggert, L., Touch, J., Westerlund, M., and S. 332 Cheshire, "Internet Assigned Numbers Authority (IANA) 333 Procedures for the Management of the Service Name and 334 Transport Protocol Port Number Registry", BCP 165, RFC 335 6335, August 2011. 337 12.2. Informative References 339 [RFC4742] Wasserman, M. and T. Goddard, "Using the NETCONF 340 Configuration Protocol over Secure SHell (SSH)", RFC 4742, 341 December 2006. 343 [RFC5539] Badra, M., "NETCONF over Transport Layer Security (TLS)", 344 RFC 5539, May 2009. 346 Appendix A. Changes from RFC 5539 348 This section summarizes major changes between this document and RFC 349 5539. 351 o Documented that NETCONF over TLS uses the new message framing if 352 both peers support the :base:1.1 capability. 354 o Removed redundant text that can be found in the TLS and NETCONF 355 specifications and restructured the text. Alignment with 356 [RFC6125]. 358 o Added a high-level description how NETCONF usernames are derived 359 from certificates. 361 o Removed the reference to BEEP. 363 Appendix B. Change Log 365 [[CREF2: RFC Editor: Please remove this appendix before publication. 366 --JS]] 368 B.1. draft-ietf-netconf-rfc5539bis-07 370 o Limited the scope of the document to TLS with mutual X.509 371 authentication. 373 o Added a high-level description how NETCONF usernames are extracted 374 from certificates. 376 o Editorial changes 378 B.2. draft-ietf-netconf-rfc5539bis-06 380 o Removed all call-home related text. 382 o Removed redundant text as discussed at the Toronto IETF meeting. 384 B.3. draft-ietf-netconf-rfc5539bis-05 386 o Removed the YANG configuration data model since it became a 387 separate document. 389 o Added reference to RFC 3234 plus editorial updates. 391 B.4. draft-ietf-netconf-rfc5539bis-04 393 o Added the applicability statement proposed by Stephen Hanna. 395 o Added call-home configuration objects and a tls-call-home feature. 397 o Rewrote the text such that the role swap happens right after the 398 TCP connection has been established. 400 B.5. draft-ietf-netconf-rfc5539bis-03 402 o Added support for call home (allocation of a new port number, 403 rewrote text to allow a NETCONF client to be a TLS server and a 404 NETCONF server to be a TLS client). 406 o Merged sections 2 and 3 into a new section 2 and restructured the 407 text. 409 o Extended the IANA considerations section. 411 o Using the cert-to-name mapping grouping from the SNMP 412 configuration data model and updated the examples. 414 o Creating an extensible set of YANG (sub)modules for NETCONF 415 following the (sub)module structure of the SNMP configuration 416 model. 418 B.6. draft-ietf-netconf-rfc5539bis-02 420 o Addressed remaining issues identified at IETF 85 422 * Harmonized the cert-maps container of the YANG module in this 423 draft with the tlstm container in the ietf-snmp-tls sub-module 424 specified in draft-ietf-netmod-snmp-cfg. Replaced the children 425 of the cert-maps container with the children copied from the 426 tlstm container of the ietf-snmp-tls sub-module. 428 * Added an overview of data model in the ietf-netconf-tls YANG 429 module. 431 * Added example configurations. 433 o Addessed issues posted on NETCONF WG E-mail list. 435 o Deleted the superfluous tls container that was directly below the 436 netconf-config container. 438 o Added a statement to the text indicating that support for mapping 439 X.509 certificates to NETCONF usernames is optional. This is 440 analogous to existing text indicating that support for mapping 441 pre-shared keys to NETCONF usernames is optional. Resource- 442 constrained systems now can omit support for mapping X.509 443 certificates to NETCONF usernames and still comply with this 444 specification. 446 o Clarified the document structure by promoting the sections of the 447 document related to the data model. 449 o Updated author's addresses. 451 B.7. draft-ietf-netconf-rfc5539bis-00 453 o Remove the reference to BEEP. 455 o Rename host-part to domain-part in the description of RFC822. 457 Authors' Addresses 459 Mohamad Badra 460 Zayed University 462 Email: mbadra@gmail.com 463 Alan Luchuk 464 SNMP Research, Inc. 465 3001 Kimberlin Heights Road 466 Knoxville, TN 37920 467 USA 469 Phone: +1 865 573 1434 470 Email: luchuk@snmp.com 471 URI: http://www.snmp.com/ 473 Juergen Schoenwaelder 474 Jacobs University Bremen 475 Campus Ring 1 476 28759 Bremen 477 Germany 479 Phone: +49 421 200 3587 480 Email: j.schoenwaelder@jacobs-university.de 481 URI: http://www.jacobs-university.de/