Hi,
Based on feedback from the group, we have written a draft for a new
routing header. The functionality is the same as the RH0. The draft
will soon be posted to the IETF site.
The main differences are:
1. Maximum up to 4 addresses in the header. (the number is based on
the reply I got for the question about the usage scenarios in operator
environments).
2. Only one header in each packet.
3. Firewall policy reccomendation.
4. RPF reccomendation.
Please have a look and let us know your comments.
Thanks,
Vishwas
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
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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].
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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
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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].
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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.
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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]:
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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
}
}
}
}
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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.
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[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.
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Authors' Addresses
Vishwas Manral
IP Infusion Inc,
Bamankhola
Bansgali
Almora - Uttaranchal
Phone: +91 98456 61911
Email: [EMAIL PROTECTED]
Manoj Dutta
IP Infusion Inc,
125, S. Market Street,
San Jose, CA
Phone: 408 794 1500
Email: [EMAIL PROTECTED]
Manral Expires February 28, 2008 [Page 9]
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