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Versions: (draft-nalluri-dhc-dhcpv6-lwm2m-bootstrap-options) 00

DHC working group                                             S. Nalluri
Internet-Draft                                                  Ericsson
Intended status: Standards Track                         August 28, 2017
Expires: March 1, 2018


             DHCPv6 Options for LWM2M bootstrap information
            draft-ietf-dhc-dhcpv6-lwm2m-bootstrap-options-00

Abstract

   This document defines Dynamic Host Configuration Protocol and Dynamic
   Host Configuration Protocol version 6 (DHCPv6) Options for LWM2M
   client bootstrap information, which are used to carry Uniform
   Resource Locater of LWM2M bootstrap server and certificate that
   validates the public key presented by server.

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
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   This Internet-Draft will expire on March 1, 2018.

Copyright Notice

   Copyright (c) 2017 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   described in the Simplified BSD License.



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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  LWM2M bootstrap server information through DHC  . . . . . . .   3
     3.1.  DHCPv6 option for LWM2M bootstrap server URI  . . . . . .   3
     3.2.  DHCPv6 option for LWM2M server certificate  . . . . . . .   4
     3.3.  DHCPv4 option for LWM2M bootstrap server URI  . . . . . .   4
     3.4.  DHCPv4 option for LWM2M server certificate  . . . . . . .   5
   4.  LWM2M-server-certificate encoding . . . . . . . . . . . . . .   5
   5.  Appearance of Option  . . . . . . . . . . . . . . . . . . . .   6
     5.1.  Appearance of options in DHCPv6 control messages  . . . .   6
     5.2.  Appearance of options in DHCPv4 control messages  . . . .   6
   6.  Configuration Guidelines for the Server . . . . . . . . . . .   7
   7.  DHCPv4/DHCPv6 Client Behavior . . . . . . . . . . . . . . . .   7
   8.  Relay agent Behavior  . . . . . . . . . . . . . . . . . . . .   8
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .   8
   10. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . .   8
   11. IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
   12. References  . . . . . . . . . . . . . . . . . . . . . . . . .   9
     12.1.  Normative References . . . . . . . . . . . . . . . . . .   9
     12.2.  Informative References . . . . . . . . . . . . . . . . .  10
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  10

1.  Introduction

   Light weight machine to machine (LWM2M) protocol is used to manage
   end device life cycle in machine to machine communication scenarios.
   LWM2M device bootstrap is an optional life cycle phase for devices to
   get needed information when starting up for first time.  Information
   gathered during bootstrapping might include management server details
   and security certificates required to establish connectivity with
   management server.  Information required to connect with bootstrap
   server might be hard coded during device manufacturing phase.

   Hard coding configuration by device manufacturer forces device
   operator to use same configuration as hard coded.  It is possible
   that reachability information of bootstrap server that is hard coded
   may be outdated and boot strap server reachability might fail during
   first use of device.  In such cases connectivity with bootstrap
   server is possible only through device software upgrade.

2.  Terminology

   This document makes use of the following terms:






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   LWM2M:  Lightweight Machine to Machine is a protocol from Open Mobile
      alliance for device management in M2M or Internet of Things
      scenarios

   LWM2M bootstrap server:  The server that provides LWM2M bootstrap
      interface which is used to optionally configure a LWM2M Client so
      that it can successfully register with a LWM2M management Server

   LWM2M management server:  The server that provides registration,
      device management and service enablement interface to manage a
      LWM2M client.

3.  LWM2M bootstrap server information through DHC

   LWM2M bootstrap server details like URI and security certificate can
   be collected during dynamic host configuration phase.  DHCPv4 and
   DHCPv6 options can be extended to collect LWM2M bootstrap server
   information for IPv4 and IPv6 networks respectively.  DHCPv4 or
   DHCPv6 client requests LWM2M bootstrap server URI and LWM2M server
   certificate using new options proposed in sections below

3.1.  DHCPv6 option for LWM2M bootstrap server URI

   DHCPv6 option OPTION_LWM2M_BOOTSTRAP_URI conveys URI through which
   LWM2M client can reach LWM2M bootstrap server reachable through IPv6
   network.  The format of LWM2M bootstrap server URI option is as shown
   below:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  option-code                  |         option-len            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                     LWM2M-bootstrap-URI                       |
   |                              ...                              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   option-code:  OPTION_LWM2M_BOOTSTRAP_URI

   option-len:  Length of the 'LWM2M-bootstrap-URI' field in octets

   LWM2M-bootstrap-URI:  This string is URI of LWM2M bootstrap server.
      The string is not null-terminated.







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3.2.  DHCPv6 option for LWM2M server certificate

   DHCPv6 option OPTION_LWM2M_SERVER_CERTIFICATE conveys security
   certificate which can be used by LWM2M client to establish secure
   connection with LWM2M server reachable through IPv6 network.  The
   format of LWM2M server certificate option is as shown below:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |          option-code          |         option-len            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |cert-encoding|                                                 |
   +-+-+-+-+-+-+-+                                                 +
   |                   LWM2M-server-certificate                    |
   |                    (variable length data)                     |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   option-code:  OPTION_LWM2M_SERVER_CERTIFICATE

   option-len:  Length of the 'LWM2M-server-certificate' field in octets
      + 1

   cert-encoding:  This field indicates the type of certificate or
      certificate-related information contained in LWM2M-server-
      certificate field.  See Section 4 for details.

   LWM2M-server-certificate:  Digital certificate of LWM2M server
      encoded according to cert-encoding.  See Section 4 for details

3.3.  DHCPv4 option for LWM2M bootstrap server URI

   DHCPv4 option OPTION_LWM2M_BOOTSTRAP_URI conveys URI through which
   LWM2M client can reach LWM2M bootstrap server reachable through IPv4
   network.  The format of LWM2M bootstrap server URI option is as shown
   below:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  option-code  |  option-len   |   LWM2M-bootstrap-URI         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   |                    LWM2M-bootstrap-URI                        |
   |                           ...                                 |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+




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   option-code:  OPTION_LWM2M_BOOTSTRAP_URI

   option-len:  Length of the 'LWM2M-bootstrap-URI' field in octets

   LWM2M-bootstrap-URI:  This string is URI of LWM2M bootstrap server.
      The string is not null-terminated.

3.4.  DHCPv4 option for LWM2M server certificate

   DHCPv4 option OPTION_LWM2M_SERVER_CERTIFICATE conveys security
   certificate which can be used by LWM2M client to establish secure
   connection with LWM2M server reachable through IPv4 network.  The
   format of LWM2M server certificate option is as shown below:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  option-code  |   option-len  | cert-encoding |               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+               +
   |                                                               |
   |                    LWM2M-server-certificate                   |
   |                     (variable length data)                    |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   option-code:  OPTION_LWM2M_SERVER_CERTIFICATE

   option-len:  Length of the 'LWM2M-server-certificate' field in octets
      + 1

   cert-encoding:  This field indicates the type of certificate or
      certificate-related information contained in LWM2M-server-
      certificate field.  See Section 4 for details.

   LWM2M-server-certificate:  Digital certificate of LWM2M server
      encoded according to cert-encoding.  See Section 4 for details

4.  LWM2M-server-certificate encoding

   As defined in Section 3.6 of [RFC7296] and [IKEv2IANA] the values in
   the following table are allocated for Certificate Encoding types.
   Other values may have been added since then or will be added after
   the publication of this document.  Readers should refer to
   [IKEv2IANA] for latest values.







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     Value            Certificate Encoding
     ------------------------------------------
      0                Reserved
      1                PKCS #7 wrapped X.509 certificate
      2                PGP Certificate
      3                DNS Signed Key
      4                X.509 Certificate - Signature
      5                Reserved
      6                Kerberos Token
      7                Certificate Revocation List (CRL)
      8                Authority Revocation List (ARL)
      9                SPKI Certificate
     10                X.509 Certificate - Attribute
     11                Raw RSA Key (DEPRECATED)
     12                Hash and URL of X.509 certificate
     13                Hash and URL of X.509 bundle
     14                OCSP Content
     15                Raw Public Key
     16-200            Unassigned
     201-255           Private use

5.  Appearance of Option

5.1.  Appearance of options in DHCPv6 control messages

   The OPTION_LWM2M_BOOTSTRAP_URI and OPTION_LWM2M_SERVER_CERTIFICATE
   options MUST NOT appear in messages other than the following: SOLICIT
   (1), ADVERTISE (2), REQUEST (3),REPLY (4) RENEW (5), REBIND (6),
   INFORMATION-REQUEST (11).  If this option appears in messages other
   than those specified above, the receiver MUST ignore it.

   The option number for OPTION_LWM2M_BOOTSTRAP_URI and
   OPTION_LWM2M_SERVER_CERTIFICATE options MAY appear in the "Option
   Request" option [RFC3315] in the following messages: SOLICIT (1),
   REQUEST (3), RENEW (5), REBIND (6), INFORMATION-REQUEST (11) and
   RECONFIGURE (10).  If this option number appears in the "Option
   Request" option in messages other than those specified above, the
   receiver SHOULD ignore it.

5.2.  Appearance of options in DHCPv4 control messages

   The OPTION_LWM2M_BOOTSTRAP_URI and OPTION_LWM2M_SERVER_CERTIFICATE
   options MUST NOT appear in messages other than the following:
   DHCPDISCOVER (1), DHCPOFFER (2), DHCPREQUEST (3), DHCPACK (5) and
   DHCPINFORM (8).  If this option appears in messages other than those
   specified above, the receiver MUST ignore it.





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   The option number for OPTION_LWM2M_BOOTSTRAP_URI and
   OPTION_LWM2M_SERVER_CERTIFICATE options MAY appear in the "Parameter
   Request List" option [RFC2132] in the following messages:
   DHCPDISCOVER (1), DHCPOFFER (2), DHCPREQUEST (3), DHCPACK (5) and
   DHCPINFORM (8).  If this option number appears in the "Parameter
   Request List" option in messages other than those specified above,
   the receiver SHOULD ignore it.

   Maximum possible value of DHCPv4 "option-len" is 255.  LWM2M-server-
   certificate MAY be of length more than 255.  To accommodate larger
   certificate, DHCP server SHOULD follow encoding as mentioned in
   [RFC3396].

6.  Configuration Guidelines for the Server

   DHCPv4 or DHCPv6 server that supports OPTION_LWM2M_BOOTSTRAP_URI and
   OPTION_LWM2M_SERVER_CERTIFICATE SHOULD be configured with one and
   only one LWM2M bootstrap server URI, and one and only one certificate
   that validates bootstrap server's public key.

   In the absence of URI configuration, DHCP server SHOULD ignore option
   OPTION_LWM2M_BOOTSTRAP_URI, and SHOULD continue processing of DHCP
   control message

   In the absence of certificate configuration, DHCP server SHOULD
   ignore option OPTION_LWM2M_SERVER_CERTIFICATE, and SHOULD continue
   processing of DHCP control message

7.  DHCPv4/DHCPv6 Client Behavior

   DHCP or DHCPv6 client MAY decide need for inclusion of
   OPTION_LWM2M_BOOTSTRAP_URI and OPTION_LWM2M_SERVER_CERTIFICATE
   options in DHCPv4 or DHCPv6 control messages if device is capable of
   supporting LWM2M client functionality irrespective of state of LWM2M
   client.  It is possible that LWM2M client MAY not be active before
   DHCPv4 or DHCPv6 message exchanges happens.  In such scenario, DHCPv4
   or DHCPv6 client MAY collect LWM2M bootstrap server URI and LWM2M
   server certificate and keep ready for LWM2M client initialization

   DHCPv4 or DHCPv6 client MAY prefer collecting LWM2M bootstrap server
   URI and LWM2M server certificate by including
   OPTION_LWM2M_BOOTSTRAP_URI and OPTION_LWM2M_SERVER_CERTIFICATE
   options in DHCPINFORM or INFORMATION-REQUEST message which MAY be
   send during LWM2M client initialization

   LWM2M client devices running with IPv6 stack MAY use stateless auto
   address configuration to get IPv6 address.  Such clients MAY use
   DHCPv6 INFORMATION-REQUEST to get LWM2M bootstrap URI and LWM2M



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   server server certificate through options OPTION_LWM2M_BOOTSTRAP_URI
   and OPTION_LWM2M_SERVER_CERTIFICATE

8.  Relay agent Behavior

   This draft does not impose any new requirements on DHCPv4 or DHCPv6
   relay agent functionality

9.  Security Considerations

   OPTION_LWM2M_BOOTSTRAP_URI and OPTION_LWM2M_SERVER_CERTIFICAT options
   could be used by an intruder to advertise the URI of a malicious
   LWM2M bootstrap server and certificate and can alter the LWM2M
   management server details provided to LWM2M client.  The consequences
   of such an attack can be critical, because any data that is reported
   by LWM2M client MAY reach unwanted LWM2M management server.  As an
   example, an attacker could collect data from secure locations by
   deploying malicious servers.

   To prevent these attacks, it is strongly advisable to secure the use
   of this option by either:

   o  Using authenticated DHCP as described in [RFC3315], Section 21.

   o  Using options OPTION_LWM2M_BOOTSTRAP_URI and
      OPTION_LWM2M_SERVER_CERTIFICATE only with trusted DHCP server

   The security considerations documented in [RFC3315] are to be
   considered.

10.  Acknowledgement

   Particular thanks to A.  Keraenen, J.  Jimenez, J.  Melen and S.
   Krishnan for the concept, inputs and review.

11.  IANA Considerations

   IANA is requested to assign new DHCPv6 option codes in the registry
   maintained in http://www.iana.org/assignments/dhcpv6-parameters:

             |       Option Name               |    Value |
             |---------------------------------+----------|
             | OPTION_LWM2M_BOOTSTRAP_URI      |     TBA  |
             | OPTION_LWM2M_SERVER_CERTIFICATE |     TBA  |

   IANA is requested to assign new DHCPv4 option codes in the registry
   maintained in http://www.iana.org/assignments/bootp-dhcp-parameters:




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             |       Option Name              |   Value |
             |--------------------------------+---------|
             | OPTION_LWM2M_BOOTSTRAP_URI     |    TBA  |
             | OPTION_LWM2M_SERVER_CERTIFICATE|    TBA  |

12.  References

12.1.  Normative References

   [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/info/rfc2119>.

   [RFC2131]  Droms, R., "Dynamic Host Configuration Protocol",
              RFC 2131, DOI 10.17487/RFC2131, March 1997,
              <https://www.rfc-editor.org/info/rfc2131>.

   [RFC2132]  Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor
              Extensions", RFC 2132, DOI 10.17487/RFC2132, March 1997,
              <https://www.rfc-editor.org/info/rfc2132>.

   [RFC3315]  Droms, R., Ed., Bound, J., Volz, B., Lemon, T., Perkins,
              C., and M. Carney, "Dynamic Host Configuration Protocol
              for IPv6 (DHCPv6)", RFC 3315, DOI 10.17487/RFC3315, July
              2003, <https://www.rfc-editor.org/info/rfc3315>.

   [RFC3396]  Lemon, T. and S. Cheshire, "Encoding Long Options in the
              Dynamic Host Configuration Protocol (DHCPv4)", RFC 3396,
              DOI 10.17487/RFC3396, November 2002, <https://www.rfc-
              editor.org/info/rfc3396>.

   [RFC4306]  Kaufman, C., Ed., "Internet Key Exchange (IKEv2)
              Protocol", RFC 4306, DOI 10.17487/RFC4306, December 2005,
              <https://www.rfc-editor.org/info/rfc4306>.

   [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/info/rfc5280>.

   [RFC7227]  Hankins, D., Mrugalski, T., Siodelski, M., Jiang, S., and
              S. Krishnan, "Guidelines for Creating New DHCPv6 Options",
              BCP 187, RFC 7227, DOI 10.17487/RFC7227, May 2014,
              <https://www.rfc-editor.org/info/rfc7227>.





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   [RFC7296]  Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T.
              Kivinen, "Internet Key Exchange Protocol Version 2
              (IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October
              2014, <https://www.rfc-editor.org/info/rfc7296>.

12.2.  Informative References

   [IKEv2IANA]
              "Internet Key Exchange Version 2 (IKEv2) Parameters",
              n.d., <https://www.iana.org/assignments/ikev2-parameters/
              ikev2-parameters.xhtml>.

Author's Address

   Srinivas Rao Nalluri
   Ericsson
   Bangalore
   India

   Email: srinivasa.rao.nalluri@ericsson.com































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