One document matched: draft-ietf-netconf-tls-07.xml


<?xml version="1.0" encoding="UTF-8"?>

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<rfc category="std" docName="draft-ietf-netconf-tls-07.txt" 
     ipr="trust200811">
<?rfc toc="yes"?>
<?rfc tocompact="yes"?>
<?rfc tocdepth="3"?>
<?rfc tocindent="yes"?>
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<?rfc sortrefs="yes"?>
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<front>
  <title abbrev="NETCONF over TLS">
     NETCONF Over Transport Layer Security (TLS)
  </title>
  <author fullname="Mohamad Badra" initials="M."
            surname="Badra">
    <organization>CNRS/LIMOS Laboratory</organization>
    <address>
      <postal>
	<street>Campus de cezeaux, Bat. ISIMA</street>
	<city>Aubiere</city>
	<region></region>
	<code>63170</code>
	<country>Fance</country>
      </postal>
      <email>badra@isima.fr</email>
    </address>
  </author>

  <date month="February" year="2009" />
  <area>Management</area>
  <workgroup>NETCONF Working Group</workgroup>

    <note title="">
  <t> This document may contain material from IETF Documents or IETF
      Contributions published or made publicly available before 	November 10, 2008. The person(s) controlling the copyright in 
	some of this material may not have granted the IETF Trust the 
	right to allow modifications of such material outside the IETF 
	Standards Process.  Without obtaining an adequate license from 
	the person(s) controlling the copyright in such materials, this 
	document may not be modified outside the IETF Standards 	Process, and derivative works of it may not be created outside 
	the IETF Standards Process, except to format it for publication 	as an RFC or to translate it into languages other than English. 	</t>
    </note>


 <abstract>
  <t>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.</t>
 </abstract>
</front>

<middle>
    <section title="Introduction">
     <t>The NETCONF protocol <xref target="RFC4741"/> 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 reliable, sequenced data 
	delivery, integrity and confidentiality and peers authentication.</t> 

	<t>This document defines "NETCONF over TLS", which includes support 
	for certificate-based mutual authentication and key derivation, 
	utilizing the protected ciphersuite negotiation, mutual 
	authentication and key management capabilities of the TLS 
	(Transport Layer Security) protocol, described in <xref 
	target="RFC5246"/>.</t> 

	<t>Throughout this document, the terms "client" and "server" are 
	used to refer to the two ends of the TLS connection.  The client 
	actively opens the TLS connection, and the server passively 
	listens for the incoming TLS connection.  The terms "manager" and 
	"agent" are used to refer to the two ends of the NETCONF protocol 
	session.  The manager issues NETCONF remote procedure call (RPC) 
	commands, and the agent replies to those commands.  When NETCONF 
	is run over TLS using the mapping defined in this document, the 
	client is always the manager, and the server is always the agent.</t>
    <section title="Conventions Used in this Document">
	<t>
	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 
	<xref target="RFC2119"></xref>.
	</t>
    </section>
    </section>

    <section title="NETCONF over TLS">
	<t>
	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.
	</t>

    <section title="Connection Initiation">
	<t>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 incoming TLS connection on the TCP port <IANA-to-be-assigned>.  
	(Note to RFC Editor: please replace <IANA-to-be-assigned> with the 	
	IANA-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 exchange NETCONF data.  In particular, 
	the client will send complete XML documents to the server 
	containing <rpc> elements, and the server will respond with 
	complete XML documents containing <rpc-reply> elements.  The 
	client MAY indicate interest in receiving event notifications 
	from a server by creating a subscription to receive event 
	notifications <xref target="RFC5277"/>, in which case the server 
	replies to indicate whether the subscription request was 
	successful and, if it was successful, begins sending the event 
	notifications to the client as the events occur within the 
	system.</t> 

	<t>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.</t> 

	<t>This document uses the same delimiter sequence ("]]>]]>") defined 
	in <xref target="RFC4742"/>, which MUST be sent by both the 
	client and the server after each XML document in the NETCONF 
	exchange.  Since this character sequence can legally appear in 
	plain XML in attribute values, comments, and processing 
	instructions, implementations of this document MUST ensure that 
	this character sequence is never part of a NETCONF message.</t> 

	<t>Implementation of the protocol specified in this document MAY 
	implement any TLS cipher suite that provides certificate-based 
	mutual authentication <xref target="RFC5246"/>.</t> 

	<t>
	Implementations MUST support TLS 1.2 <xref target="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.
	</t>
    </section>

    <section title="Connection Closure">
	<t>
	A TLS client (NETCONF manager) MUST close the associated TLS 
	connection if the connection is not expected to issue any NETCONF 
	RPC 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 server (NETCONF agent) close_notify alert and simply 
	close the connection, thus generating an incomplete close on the 
	TLS server side.  Once the TLS server gets a close_notify from 
	the TLS client, it MUST reply with a close_notify unless it 
	becomes aware that the connection has already been closed by the 
	TLS client (e.g., the closure was indicated by TCP).
	</t> 
	<t>
	When no data is received from a connection for a long time (where 
	the application decides what "long" means), a NETCONF peer MAY 
	close the connection.  The NETCONF peer MUST attempt to initiate 
	an exchange of close_notify alerts with the other NETCONF peer 
	before closing the connection.  The close_notify's sender that is 
	unprepared to receive any more data MAY close the connection 
	after sending the close_notify alert, thus generating an 
	incomplete close on the close_notify's receiver side. 
	</t>
    </section>
   </section>

   <section title="Endpoint Authentication and Identification">
     <section title="Server Identity">
	<t>
	During the TLS negotiation, the client MUST carefully examine the 
	certificate presented by the server to determine if it meets 
	their 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.
	</t> 
	<t>
	Matching is performed according to the rules below (following the 
	example of <xref target="RFC4642"/>):
	<list style="symbols">
		<t>The client MUST use the server hostname it used to open the 
		connection (or the hostname specified in TLS "server_name" 
		extension <xref target="RFC5246"/>) as the value to compare 
		against the server name as expressed in the server 	
		certificate.  The client MUST NOT use any form of the 
		server hostname derived from an insecure remote source 
		(e.g., insecure DNS lookup).  CNAME canonicalization is not 
		done.</t> 
		<t>If a subjectAltName extension of type dNSName is present in 
		the certificate, it MUST be used as the source of the 
		server's identity.</t> 
		<t>Matching is case-insensitive.</t> 
		<t>A "*" wildcard character MAY be used as the leftmost name 
		component in the certificate.  For example, *.example.com 
		would match a.example.com, foo.example.com, etc., but would 
		not match example.com.</t> 
		<t>If the certificate contains multiple names (e.g., more than 
		one dNSName field), then a match with any one of the fields 
		is considered acceptable.</t>
		</list>
	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.
	</t> 
	<t>
	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 <xref target="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).
	</t> 
	<t>
	If the client has external information as to the expected 	
	identity of the server, the hostname check MAY be omitted.
	</t>
    </section>

    <section title="Client Identity">
	<t>
	The server may have no external knowledge on client's identity 
	and identity checks might not be possible (unless the client has 
	a certificate chain rooted in an appropriate CA).  If a server has 
	knowledge on client's identity (typically from some source external to 
	NETCONF or TLS) it MUST check the identity as described above.
	</t>
    </section>
   </section>

    <section title="Security Considerations">
	<t>
	The security considerations described throughout <xref target="RFC5246"/> 
	and <xref target="RFC4741"/> apply here as well.
	</t> 
	<t>
	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 and that NETCONF depends on the transport 	
	protocol for the authentication service.  If third party 	
	authentication is needed, BEEP or SSH transport can be used.
	</t> 
	<t>
	An attacker might be able to inject arbitrary NETCONF messages 
	via some application that does not carefully check exchanged 
	messages or deliberately insert the delimiter sequence in a 
	NETCONF message to create a DoS attack.  Hence, applications and 
	NETCONF APIs MUST ensure that the delimiter sequence defined in 
	Section 2.1 never appears in NETCONF messages;  otherwise, those 
	messages can be dropped, garbled or mis-interpreted.  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.
	</t> 
	<t>
	Finally, this document does not introduce any new security 
	considerations compared to <xref target="RFC4742"/>.
	</t>
    </section>	

    <section title="IANA Considerations">
	<t>
	IANA is requested to assign a TCP port number 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.
<figure>
 <artwork>
	<![CDATA[
   Registration Contact:  Mohamad Badra, badra@isima.fr.
   Transport Protocol:  TCP.
   Port Number:  TBA-by-IANA (if possible, please assign 6513).
   Broadcast, Multicast or Anycast: No.
   Port Name:  netconf-tls.
   Service Name: netconf.
   Reference: draft-ietf-netconf-tls-07.
]]>
 </artwork>
</figure>
	</t>
    </section>

    <section title="Acknowledgements">
	<t>
	A significant amount of the text in Section 3 was lifted from 	
	<xref target="RFC4642"/>.
	</t> 
	<t>
	The author would like to acknowledge David Harrington, Miao 
	Fuyou, Eric Rescorla, Juergen Schoenwaelder, Simon Josefsson, 
	Olivier Coupelon, Alfred Hoenes and the NETCONF mailing list 
	members for their comments on the document.  The author 
	appreciates also 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 this 
	document.
	</t>
    </section>

<section title="Contributor's Address">
<figure>
<artwork>
Ibrahim Hajjeh
Ineovation
France

E-mail: ibrahim.hajjeh@ineovation.fr
</artwork>
</figure>
</section>

</middle>

<back>
<references title="Normative References">
&rfc2119;
&rfc4642;
&rfc4741;
&rfc4742;
&rfc5246;
&rfc5277;
&rfc5280;
</references>
		<section title="Change Log (to be removed by RFC Editor before publication)">
		<section title="06-07">
		<t>
		New trust boilerplate introduced.
		</t>
		<t>
		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.
		</t>
		<t>
		Section 2.2: Obselete RFC4366 is replaced with RFC5246.
		</t>
		<t>
		Section 2.2: s/to issues any NETCONF commands/to issue any NETCONF commands/
		</t>
		<t>
		Section 3.2: "Typically, the server has no external knowledge" is replaced with 
		"The server may have no external knowledge"
		</t>
		<t>
		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.
		</t>
		</section>
		<section title="05-06">
		<t>
		Section 5 (IANA Considerations Section): "Anycast" is replaced with "No".
		</t>
		</section>
		<section title="04-05">
		<t>
		Removed any text related to PSK based authentication.
		</t>
		<t>
		Revised to TLS with certificate-based mutual authentication.
		</t>
		<t>
		Removed Cipher Suite Requirements section which was redundant with TLS.
		</t>
		<t>
		Added small clarifications to the "Introduction" and 
		"Endpoint Authentication and Identification" sections.
		</t>
		<t>
		Section 2.1: Included mandatory to implement cipher suites that track 
		future versions of the TLS.
		</t>
		<t>
		Section 2.2: Revised the connection closure session with regards to TLS 1.2.
		</t>
		<t>
		Section 5: Revised to help IANA with the port assignment.
		</t>
		<t>
		Section 8: Removed RFC4086 and RFC4279 from the reference section
		</t>
		</section>
		</section>
</back>
</rfc>

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