Network Working Group V. Manral Internet-Draft M. Dutta Updates: 2460, 4294 IP Infusion Inc. (if approved) Intended status: Standards Track Expires: February 28, 2008 August 28, 2007 New IPv6 Type 4 Routing Header draft-manral-ipv6-rh4-00 Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on December 28, 2007. Copyright Notice Copyright (C) The IETF Trust (2007). Abstract The functionality provided by IPv6's Type 0 Routing Header can be exploited in order to achieve traffic amplification over a remote path for the purposes of generating denial-of-service traffic. This document updates the IPv6 specification to the use of a new IPv6 Type 4 Routing Header, in light of this security concern. This new header provides the same functionality of the Routing Header Type-0, while taking care of the major security concerns defined in the draft [draft-ietf-ipv6-deprecate-rh0-01]. Manral Expires February 28, 2008 [Page 1] Internet-Draft New IPv6 Type 4 Routing Header June 2007 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Format of RH4 . . . . . . . . . . . . . . . . . . . . . . . . 4 4. Security Considerations . . . . . . . . . . . . . . . . . . . . 5 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7 6. Acknowlegements . . . . . . . . . . . . . . . . . . . . . . . . 7 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7 6.1. Normative References . . . . . . . . . . . . . . . . . . . 7 6.2. Informative References . . . . . . . . . . . . . . . . . . 8 Appendix A. Change History . . . . . . . . . . . . . . . . . . . . 8 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 9 Intellectual Property and Copyright Statements . . . . . . . . . . 10 Manral Expires February 28, 2008 [Page 2] Internet-Draft New IPv6 Type 4 Routing Header June 2007 1. Introduction [RFC2460] defines an IPv6 extension header called "Routing Header", identified by a Next Header value of 43 in the immediately preceding header. A particular Routing Header subtype denoted as "Type 0" is also defined. Type 0 Routing Headers are referred to as "RH0" in this document. 128-fold amplification of data traffic can result using the IPv6 amplification attack as defined in [I-D.ietf-ipv6-deprecate-rh0-01]. This attack is particularly serious in that it affects the entire path between the two exploited nodes, not only the nodes themselves or their local networks. The draft [I-D.ietf-ipv6-deprecate-rh0-01] deprecates the use of the RH0 header. However operators use and require the functionality provided by the RH0 header. This draft defines the Routing Header of Type-4, and referred to as "RH4" header. The RH4 header has format and functionality similar to the RH0 header without having the major vulnerabilities of the "Routing Header". This document updates [RFC2460] and [RFC4294]. Manral Expires February 28, 2008 [Page 3] Internet-Draft New IPv6 Type 4 Routing Header June 2007 2. Definitions RH4 in this document denotes the IPv6 Extension Header type 43 ("Routing Header") variant 4 ("Type 4 Routing Header"), is a type of Routing header as defined in [RFC2460]. 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 [RFC2119]. 3. Format of RH4 The Type 4 Routing header has the following format (it is the same as the RH0 header except for the limit on the "Hdr Ext Len" field. Some additional restrictions and checks have been added): +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Next Header | Hdr Ext Len | Routing Type=0| Segments Left | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | | + Address[1] + | | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | | + Address[2] + | | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . . . . . . . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | | + Address[n] + | | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Next Header 8-bit selector. Identifies the type of header immediately following the Routing header. Uses the same values as the IPv4 Protocol field [RFC-1700 et seq.]. Hdr Ext Len 8-bit unsigned integer. Length of the Routing header in 8-octet units, not including the first 8 octets. For the Type 4 Routing header, Hdr Ext Len is equal to two times the number of addresses in the header. The maximum value of this field can be 8. That means a maximum of 4 addresses can be added to the Routing Header. Manral Expires February 28, 2008 [Page 4] Internet-Draft New IPv6 Type 4 Routing Header June 2007 Routing Type 4. Segments Left 8-bit unsigned integer. Number of route segments remaining, i.e., number of explicitly listed intermediate nodes still to be visited before reaching the final destination. Reserved 32-bit reserved field. Initialized to zero for transmission; ignored on reception. Address[1..n] Vector of 128-bit addresses, numbered 1 to n. The maximum value of n is 4. Multicast addresses or Link Local Unicast address must not appear in a Routing header of Type 4, or in the IPv6 Destination Address field of a packet carrying a Routing header of Type 4. A Routing header is not examined or processed until it reaches the node identified in the Destination Address field of the IPv6 header. There can be at most one RH4 header in any packet. A packet with more than one RH4 header is discarded. This functionality can be implemented in a firewall or any other IPv6 node. In that node, dispatching on the Next Header field of the immediately preceding header causes the Routing header module to be invoked, which, in the case of Routing Type 4, performs the algorithm which is similar to the as specified in section 4.4 of [RFC2460]: Manral Expires February 28, 2008 [Page 5] Internet-Draft New IPv6 Type 4 Routing Header June 2007 if Segments Left = 0 { proceed to process the next header in the packet, whose type is identified by the Next Header field in the Routing header } else if Hdr Ext Len is odd { send an ICMP Parameter Problem, Code 0, message to the Source Address, pointing to the Hdr Ext Len field, and discard the packet } else { compute n, the number of addresses in the Routing header, by dividing Hdr Ext Len by 2 if Segments Left is greater than n or n is greater than 4 { send an ICMP Parameter Problem, Code 0, message to the Source Address, pointing to the Segments Left field, and discard the packet } else { decrement Segments Left by 1; compute i, the index of the next address to be visited in the address vector, by subtracting Segments Left from n if Address [i] or the IPv6 Destination Address is multicast or link local unicast address { discard the packet } else { Compare the addresses in the Routing Header to check that none of the address belong to the routers self address if overlapping address exist { discard the packet } swap the IPv6 Destination Address and Address[i] if the IPv6 Hop Limit is less than or equal to 1 { send an ICMP Time Exceeded -- Hop Limit Exceeded in Transit message to the Source Address and discard the packet } else { decrement the Hop Limit by 1 resubmit the packet to the IPv6 module for transmission to the new destination } } } } Manral Expires February 28, 2008 [Page 6] Internet-Draft New IPv6 Type 4 Routing Header June 2007 4. Security Considerations The purpose of this document is to add a new type of Routing extension header of IPv6. RH0 has been shown to have undesirable security implications. Many of the attacks including the amplification attack cannot occur with the RH4 header. All the addresses in the RH4 header need to be checked with the firewall policy to make sure the firewall is able to trap packets meant for addresses in the firewall policy and take relevent action. Whereever possible, including the administrative network edge, RPF check needs to be done. 5. IANA Considerations The IANA registry "Internet Protocol Version 6 (IPv6) Parameters" should be updated to reflect that variant 4 of IPv6 header-type 43 ("Routing Header") is added. 7. Acknowlegements This document benefits from the contributions of many IPV6 and V6OPS working group participants, including Chris Morrow, Tony Hain, Jinmei Tatuya and Brian Carpenter. 8. References 8.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. Manral Expires February 28, 2008 [Page 7] Internet-Draft New IPv6 Type 4 Routing Header June 2007 [RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6 (IPv6) Specification", RFC 2460, December 1998. [RFC4294] Loughney, J., "IPv6 Node Requirements", RFC 4294, April 2006. 8.2. Informative References [CanSecWest07] BIONDI, P. and A. EBALARD, "IPv6 Routing Header Security", CanSecWest Security Conference 2007, April 2007. http://www.secdev.org/conf/IPv6_RH_security-csw07.pdf [I-D.ietf-v6ops-security-overview] Davies, E., "IPv6 Transition/Co-existence Security Considerations", draft-ietf-v6ops-security-overview-06 (work in progress), October 2006. [I-D.savola-ipv6-rh-ha-security] Savola, P., "Security of IPv6 Routing Header and Home Address Options", draft-savola-ipv6-rh-ha-security-02 (work in progress), March 2002. [I-D.savola-ipv6-rh-hosts] Savola, P., "Note about Routing Header Processing on IPv6 Hosts", draft-savola-ipv6-rh-hosts-00 (work in progress), February 2002. [RFC2827] Ferguson, P. and D. Senie, "Network Ingress Filtering: Defeating Denial of Service Attacks which employ IP Source Address Spoofing", BCP 38, RFC 2827, May 2000. [RFC3704] Baker, F. and P. Savola, "Ingress Filtering for Multihomed Networks", BCP 84, RFC 3704, March 2004. [RFC3775] Johnson, D., Perkins, C., and J. Arkko, "Mobility Support in IPv6", RFC 3775, June 2004. Appendix A. Change History This section to be removed prior to publication. Manral Expires February 28, 2008 [Page 8] Internet-Draft New IPv6 Type 4 Routing Header June 2007 Authors' Addresses Vishwas Manral IP Infusion Inc, Bamankhola Bansgali Almora - Uttaranchal Phone: +91 98456 61911 Email: vishwas@ipinfusion.com Manoj Dutta IP Infusion Inc, 125, S. Market Street, San Jose, CA Phone: 408 794 1500 Email: manoj@ipinfusion.com Manral Expires February 28, 2008 [Page 9] Internet-Draft New IPv6 Type 4 Routing Header June 2007 Full Copyright Statement Copyright (C) The IETF Trust (2007). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 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The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Acknowledgment Funding for the RFC Editor function is provided by the IETF Administrative Support Activity (IASA). Manral Expires February 28, 2008 [Page 10]