draft-ietf-6man-oversized-header-chain-04.txt   draft-ietf-6man-oversized-header-chain-05.txt 
IPv6 maintenance Working Group (6man) F. Gont IPv6 maintenance Working Group (6man) F. Gont
Internet-Draft SI6 Networks / UTN-FRH Internet-Draft SI6 Networks / UTN-FRH
Updates: 2460 (if approved) V. Manral Updates: 2460 (if approved) V. Manral
Intended status: Standards Track Hewlett-Packard Corp. Intended status: Standards Track Hewlett-Packard Corp.
Expires: February 14, 2014 R. Bonica Expires: March 4, 2014 R. Bonica
Juniper Networks Juniper Networks
August 13, 2013 August 31, 2013
Implications of Oversized IPv6 Header Chains Implications of Oversized IPv6 Header Chains
draft-ietf-6man-oversized-header-chain-04 draft-ietf-6man-oversized-header-chain-05
Abstract Abstract
The IPv6 specification allows IPv6 header chains of an arbitrary The IPv6 specification allows IPv6 header chains of an arbitrary
size. The specification also allows options which can in turn extend size. The specification also allows options which can in turn extend
each of the headers. In those scenarios in which the IPv6 header each of the headers. In those scenarios in which the IPv6 header
chain or options are unusually long and packets are fragmented, or chain or options are unusually long and packets are fragmented, or
scenarios in which the fragment size is very small, the first scenarios in which the fragment size is very small, the first
fragment of a packet may fail to include the entire IPv6 header fragment of a packet may fail to include the entire IPv6 header
chain. This document discusses the interoperability and security chain. This document discusses the interoperability and security
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on February 14, 2014. This Internet-Draft will expire on March 4, 2014.
Copyright Notice Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the Copyright (c) 2013 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 Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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document are to be interpreted as described in RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
3. Terminology 3. Terminology
For the purposes of this document, the terms Extension Header, Header For the purposes of this document, the terms Extension Header, Header
Chain, First Fragment, and Upper-layer Header are used as follows: Chain, First Fragment, and Upper-layer Header are used as follows:
Extension Header: Extension Header:
Extension Headers are defined in Section 4 of [RFC2460]. Extension Headers are defined in Section 4 of [RFC2460].
Currently, six extension header types are defined. [RFC2460] [IANA-PROTO] provides a list of assigned Internet Protocol Numbers
defines the Hop-by-Hop, Routing, Fragment and Destination Options and designates which of those protocol numbers also represent
extension header types. [RFC4302] defines the Authentication extension headers.
Header (AH) type and [RFC4303] defines the Encapsulating Security
Payload (ESP) header type.
First Fragment: First Fragment:
An IPv6 fragment with fragment offset equal to 0. An IPv6 fragment with fragment offset equal to 0.
IPv6 Header Chain: IPv6 Header Chain:
The header chain contains an initial IPv6 header, zero or more The header chain contains an initial IPv6 header, zero or more
IPv6 extension headers, and optionally, a single upper-layer IPv6 extension headers, and optionally, a single upper-layer
header. If an upper-layer header is present, it terminates the header. If an upper-layer header is present, it terminates the
header chain. header chain.
The first member of the header chain is always an IPv6 header. The first member of the header chain is always an IPv6 header.
For a subsequent header to qualify as a member of the header For a subsequent header to qualify as a member of the header
chain, it must be referenced by the "Next Header" field of the chain, it must be referenced by the "Next Header" field of the
previous member of the header chain. However, if a second IPv6 previous member of the header chain. However, if a second IPv6
header appears in the header chain, as is the case when IPv6 is header appears in the header chain, as is the case when IPv6 is
tunneled over IPv6, the second IPv6 header is considered to be an tunneled over IPv6, the second IPv6 header is considered to be an
upper-layer header and terminates the header chain. Likewise, if upper-layer header and terminates the header chain. Likewise, if
an ESP header appears in the header chain it is considered to be an Encapsulating Security Payload (ESP) header appears in the
an upper-layer header and it terminates the header chain. header chain it is considered to be an upper-layer header and it
terminates the header chain.
Upper-layer Header: Upper-layer Header:
In the general case, the upper-layer header is the first member of In the general case, the upper-layer header is the first member of
the header chain that is neither an IPv6 header nor an IPv6 the header chain that is neither an IPv6 header nor an IPv6
extension header. However, if either an ESP header, or a second extension header. However, if either an ESP header, or a second
IPv6 header occur in the header chain, they are considered to be IPv6 header occur in the header chain, they are considered to be
upper layer headers and they terminate the header chain. upper layer headers and they terminate the header chain.
Neither the upper-layer payload, nor any protocol data following Neither the upper-layer payload, nor any protocol data following
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Likewise, an intermediate system (e.g. router, firewall) that Likewise, an intermediate system (e.g. router, firewall) that
receives an IPv6 first-fragment that does not satisfy the above- receives an IPv6 first-fragment that does not satisfy the above-
stated requirements MAY discard that packet, and MAY send an ICMPv6 stated requirements MAY discard that packet, and MAY send an ICMPv6
error message to the source address of the offending packet (subject error message to the source address of the offending packet (subject
to the rules for ICMPv6 error messages specified in [RFC4443]). to the rules for ICMPv6 error messages specified in [RFC4443]).
Intermediate systems having this capability SHOULD support Intermediate systems having this capability SHOULD support
configuration (e.g. enable/disable) of whether such packets are configuration (e.g. enable/disable) of whether such packets are
dropped or not by the intermediate system. dropped or not by the intermediate system.
If a host or intermediate system discards an first-fragment because If a host or intermediate system discards a first-fragment because it
it does not satisfy the above-stated requirements, and sends an does not satisfy the above-stated requirements, and sends an ICMPv6
ICMPv6 error message due to the discard, then the ICMPv6 error error message due to the discard, then the ICMPv6 error message MUST
message MUST be Type 4 ("Parameter Problem") and MUST use Code TBD be Type 4 ("Parameter Problem") and MUST use Code TBD ("First-
("First-fragment has incomplete IPv6 Header Chain"). fragment has incomplete IPv6 Header Chain"). The Pointer field
contained by the ICMPv6 Parameter Problem message MUST be set to
zero.
6. IANA Considerations 6. IANA Considerations
IANA is requested to add a the following entry to the "Reason Code" IANA is requested to add a the following entry to the "Reason Code"
registry for ICMPv6 "Type 4 - Parameter Problem" messages: registry for ICMPv6 "Type 4 - Parameter Problem" messages:
CODE NAME/DESCRIPTION CODE NAME/DESCRIPTION
TBD IPv6 first-fragment has incomplete IPv6 header chain TBD IPv6 first-fragment has incomplete IPv6 header chain
7. Security Considerations 7. Security Considerations
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forged illegal packets with the victim/target's IPv6 address as the forged illegal packets with the victim/target's IPv6 address as the
IPv6 Source Address of the illegal packet [RFC2827] [RFC3704]. IPv6 Source Address of the illegal packet [RFC2827] [RFC3704].
8. Acknowledgements 8. Acknowledgements
The authors of this document would like to thank Ran Atkinson for The authors of this document would like to thank Ran Atkinson for
contributing text and ideas that were incorporated into this contributing text and ideas that were incorporated into this
document. document.
The authors would like to thank (in alphabetical order) Ran Atkinson, The authors would like to thank (in alphabetical order) Ran Atkinson,
Fred Baker, Brian Carpenter, Dominik Elsbroek, Bill Jouris, Suresh Fred Baker, Brian Carpenter, Dominik Elsbroek, Mike Heard, Bill
Krishnan, Dave Thaler, and Eric Vyncke, for providing valuable Jouris, Suresh Krishnan, Dave Thaler, Ole Troan, and Eric Vyncke, for
comments on earlier versions of this document. providing valuable comments on earlier versions of this document.
9. References 9. References
9.1. Normative References 9.1. 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.
[RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6 [RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", RFC 2460, December 1998. (IPv6) Specification", RFC 2460, December 1998.
[RFC4302] Kent, S., "IP Authentication Header", RFC 4302,
December 2005.
[RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)",
RFC 4303, December 2005.
[RFC4443] Conta, A., Deering, S., and M. Gupta, "Internet Control [RFC4443] Conta, A., Deering, S., and M. Gupta, "Internet Control
Message Protocol (ICMPv6) for the Internet Protocol Message Protocol (ICMPv6) for the Internet Protocol
Version 6 (IPv6) Specification", RFC 4443, March 2006. Version 6 (IPv6) Specification", RFC 4443, March 2006.
9.2. Informative References 9.2. Informative References
[RFC2827] Ferguson, P. and D. Senie, "Network Ingress Filtering: [RFC2827] Ferguson, P. and D. Senie, "Network Ingress Filtering:
Defeating Denial of Service Attacks which employ IP Source Defeating Denial of Service Attacks which employ IP Source
Address Spoofing", BCP 38, RFC 2827, May 2000. Address Spoofing", BCP 38, RFC 2827, May 2000.
[RFC3704] Baker, F. and P. Savola, "Ingress Filtering for Multihomed [RFC3704] Baker, F. and P. Savola, "Ingress Filtering for Multihomed
Networks", BCP 84, RFC 3704, March 2004. Networks", BCP 84, RFC 3704, March 2004.
[IANA-PROTO]
Internet Assigned Numbers Authority, "Protocol Numbers",
February 2013, <http://www.iana.org/assignments/
protocol-numbers/protocol-numbers.txt>.
Authors' Addresses Authors' Addresses
Fernando Gont Fernando Gont
SI6 Networks / UTN-FRH SI6 Networks / UTN-FRH
Evaristo Carriego 2644 Evaristo Carriego 2644
Haedo, Provincia de Buenos Aires 1706 Haedo, Provincia de Buenos Aires 1706
Argentina Argentina
Phone: +54 11 4650 8472 Phone: +54 11 4650 8472
Email: fgont@si6networks.com Email: fgont@si6networks.com
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