Network working group Dacheng Zhang Internet Draft Xiaohu Xu Category: Standards Track Created: May 27, 2009 Huawei Technologies Co.,Ltd Expires: November 2009 Extensions of Host Identity Protocol (HIP) with Hierarchical Information draft-zhang-hip-hierarchical-parameter-00.txt Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and 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 November 27, 2009. Copyright Notice Copyright (c) 2009 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents in effect on the date of publication of this document (http://trustee.ietf.org/license-info). Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Zhang and Xu. Expires November 27, 2009 [Page 1] Internet-Draft Extensions of HIP with Hierarchical Information May 2009 Abstract This document briefly introduces the benefits brought by extending the Host Identity Protocol (HIP) with hierarchical information. In addition, two hierarchical extensions of HIP are introduced. The first one aims to transport hierarchical information in a parameter of the HIP header, while the second one extends DNS resource records in order to contain hierarchical information. Conventions used in this document 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 RFC-2119 [RFC2119]. Table of Contents 1. Introduction.................................................2 2. Benefits introduced by Hierarchical Information..............3 3. Candidate Solutions..........................................4 4. Hierarchical_HIT Parameter...................................5 5. HHIT Registration............................................7 6. Domain Name System (DNS) Extension...........................8 7. IANA Considerations..........................................9 8. Acknowledgments..............................................9 9. References...................................................9 Authors' Addresses.............................................10 1. Introduction While having obtained a tremendous success, the current Internet architecture shows its limits in many aspects. For example, the current Internet cannot well support the incorporation of mobile and multi-homed terminals, lacks essential security mechanisms, and suffers from the issues caused by the explosively increased lengths of routing tables. In order to address these challenges, a comprehensive solution, the Host Identity Protocol (HIP), was proposed. A simple principle behind HIP is to separate hosts' identities from their topological locations in the Internet. Currently, the basic architectures and protocols of HIP have been developed, which are security-inherited and provides essential supports for mobility and multi-homing features. There is no hierarchy in existing HIP names, which is largely because a flat HIP namespace is simple and easy for implementation. Zhang and Xu. Expires November 27, 2009 [Page 2] Internet-Draft Extensions of HIP with Hierarchical Information May 2009 In addition, hosts in the current HIP architecture are organized in a "flat" way. This document first analyzes the benefits introduced by integrating hierarchical information with HIP in terms of security, management, integration with hierarchical overlays and etc. Then, this document discusses the issues with the transport of hierarchical information in HIP headers and the maintenance of hierarchical information in DNS resource records. 2. Benefits introduced by Hierarchical Information Hierarchy is a practical methodology in the design and organization of non-trivial distributed systems, and has been adopted in many large-scale networks and distributed systems (e.g., Internet). It shows many advantages in terms of simplifying system architectures, improving the capability of system management, facilitating audit and security, and etc. To be consistent with the hierarchical features of the Internet, two critical namespaces of the Internet, IP and FQDN, are designed in hierarchical ways. However, based on certain concerns (e.g., easy implementation), the HIT namespace is flat; HIP itself does not provide any support for hierarchy either. This section attempts to demonstrate that current HIP, by using hierarchical information, can be more efficient and flexible in many typical scenarios. Firstly, hierarchical information is essential for the combination of HIP with hierarchical overlays (e.g., hierarchical resolution mechanisms). Compared with flat overlays where resources are maintained at essentially random nodes, hierarchical overlays are able to support reasonable business and trust models where resources are managed by Administrative Domains (ADs) with distinct boundaries. For example, it is normally not desired for a country to have its resolution infrastructure and the related data resources managed by other countries. In order to correctly route across hierarchical overlays, hierarchical information (e.g., AD identifiers) is required to identify the destination AD where the desired resources are maintained, while the resource identifiers are used to locate the resources. Secondly, the hierarchical information can be used to address the uniqueness verification issues with HITs in current HIP solutions. In current HIP solutions, the HIT of each host is required to be unique all over the world, which is very difficult to guarantee. However, if the Internet is divided into multiple administration domains, this problem is relatively easier to address. As hierarchical information (i.e., AD identifier) can be used to Zhang and Xu. Expires November 27, 2009 [Page 3] Internet-Draft Extensions of HIP with Hierarchical Information May 2009 identify the AD of a HIT, it only needs to be guaranteed that the HIT is unique within the AD. The process of verifying the uniqueness of HITs can be performed when the host registers its HIT with the AD. Moreover, hierarchical information has been widely employed in advanced authorization systems (e.g., attributes based or role-based authorization systems) to make the access control aggregates. By using AD identifiers, it is possible for security managers to design the access control policies based on the AD of hosts so as to reduce the length of access control lists. Apart from the advantages mentioned above, hierarchical information may associate HIP with better HIT administrating and auditing capabilities, which makes HIP easier to be accepted by the countries which have relatively strict management policies on their networks. 3. Candidate Solutions Basically, there are three types of solutions of embedding hierarchical information in HIT Headers. The first type of solution is to embed hierarchical information into HITs directly. For instance, divide a HIT into two parts; the first indicates the hierarchical information of the host, and the second is the identifier of the host. The principle behind this type of solution is similar with IP addresses. A criticism on this type of solution is that the capability of an identifier in tolerating attacks is affected as a part of the space of the identifier that is occupied by the topological information. This issue can be largely addressed by puzzles which have been employed in Cryptographically Generated Addresses (CGA) [RFC3972]. However, this type of solution still has an inherent disadvantage in protecting privacy. As hierarchical information is integrated with HITs, this solution is not suitable for the scenario where hosts do not intend to disclose their hierarchical information. The second type of solution is to encapsulate the hierarchical information in a certificate and transport the certificate within the CERT parameter of the HIT header. This type of solution is more flexible than the first type of solution. One can attaches the certificates to HIT headers only when hierarchical information is needed. One concern of this type of solution is its efficiency. Some parameters of a certificate (e.g., the name and the public key of the subject) are already contained in HIT headers. When using a certificate to transport hierarchical information, these parameters may have to be transported again, causing redundancy. In addition, certificates have to be signed by issuers. The signature of a Zhang and Xu. Expires November 27, 2009 [Page 4] Internet-Draft Extensions of HIP with Hierarchical Information May 2009 certificate can be used to verify the authenticity of the transported hierarchical information, which is very useful when the certificate is used to transport hierarchical information for the source HIT of a HIP packet. However, when the certificate is used to transport hierarchical information for the destination HIT of a HIP packet, the signature is redundant because the receiver of the packet needs not to verify the authenticity of its hierarchical information. Another concern is performance. A HIT can be attached with multiple certificates which are issued by diverse third parties for the various purposes. The system thus may have to go through all the certificates in order to find the proper certificate issued by the AD and use it to assess the validity of the HIT. The third type of solution is to transport hierarchical information in a parameter. Compared with the first type of solution, this solution shows its advantages in the privacy protection. The third type of solution is as flexible as the second type of solution, but more efficient. The solution proposed in this document is a third type solution, which specifies a new parameter to transport hierarchical information. 4. Hierarchical_HIT Parameter This parameter contains the information about the AD and should be transported in R1 and I2 packets of basic. Type 61698 Length length in octets, excluding Type, Length, and Padding ADI Type type of the Administration Domain Identifier field ADI Length length of the FQDN or NAI in octets NB Length length of the Not Before Time field in octets NA Length length of the Not After Time field in octets AD Identifier the identifier of the AD of the sender Not Before Time the beginning of the valid period of the HIT of the sender Not After Time the end of the valid period of the HIT of the sender Zhang and Xu. Expires November 27, 2009 [Page 5] Internet-Draft Extensions of HIP with Hierarchical Information May 2009 SIG alg signature algorithm Signature the signature is generated by the AD previously, calculated over the concatenation of Host Identity field of HOST_ID, and AD Identifier, Not Before Time, Not After Time fields of the Hierarchical_HIT parameter. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |ADIType| ADI Length | NB Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | NA Length | Sig Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SIG alg | AD Identifier / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / | Not Before Time / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / | Not After Time / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / | Signature / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / | Padding | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The following AID Types have been defined: Type Value none included 0 Zhang and Xu. Expires November 27, 2009 [Page 6] Internet-Draft Extensions of HIP with Hierarchical Information May 2009 FQDN 1 NAI 2 FQDN Fully Qualified Domain Name, in binary format. NAI Network Access Identifier The format for the FQDN is defined in RFC 1035 [RFC1035] Section 3.1. The format for NAI is defined in [RFC4282]. Not Before Time and Not After Time fields must either UTCTime or GeneralizedTime defined in [RFC2459]. SIG alg is set to 0 when there is no signature included. In this case, Sig Length is set 0 as well. 5. HHIT Registration If the authenticity of the hierarchical information of a HIT needs to be proved in practice, the HIT need to register with an AD and obtain the signature. The registration process can be whether in- band or out-of-band. In the following diagram, a protocol for HHIT registration is illustrated. +-----+ +------+ | | I1 | | | |--------------------------->| | | |<---------------------------| | | I | R1(REG_INFO) | AD | | | I2(REG_REQ) |Server| | |--------------------------->| | | |<---------------------------| | | | R2(REG_RES) | | +-----+ +------+ This protocol is an extension of basic by using the HIP Registration Extension [RFC5203]. In R1, AD Server sends the service it provides to Initiator in the REG_INFO element. Initiator then attaches the REG-REQ element and the HHIT parameter with the I2 message. The Signature field in the parameter is left unfilled. The AD server signs the HHIT and its parameters, and sends the signature back in R2. Zhang and Xu. Expires November 27, 2009 [Page 7] Internet-Draft Extensions of HIP with Hierarchical Information May 2009 6. Domain Name System (DNS) Extension This section introduces a DNS extension which further extends the HIP RR Storage Format proposed in [RFC5205]. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | HIT Length | PK algorithm | PK Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |ADIType| ADI Length | NB Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | NA Length | HIT / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / | Public Key / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / | Rendezvous Server / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / | AD Identifier / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / | Not Before Time / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / | Not After Time / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / | +-+-+-+-+ Apart from the fields illustrated in [RFC5205], the extension includes following fields: ADI type, ADI Length, NB Length, NA Length, AD Identifier, Not Before Time, Not After Time. Because the means of these fields is identical to their counterparts in the Hierarchical_HIT Parameter, they are not introduced here in detail. Zhang and Xu. Expires November 27, 2009 [Page 8] Internet-Draft Extensions of HIP with Hierarchical Information May 2009 7. IANA Considerations IANA is expected to allocate a type code for the Hierarchical_HIT Parameter 8. Acknowledgments Thanks Thomas.R.Henderson for his kindly prove-reading and precious comments. 9. References [RFC3972] Aura, T., "Cryptographically Generated Addresses (CGA)", RFC 3972, March 2005. [RFC1035] Mockapetris, P., "Domain Names - Implementation and Specification" STD 13, RFC 1035, USC/Information Sciences Institute, November 1987. [RFC5205] Nikander, P. and J. Laganier, "Host Identity Protocol (HIP) Domain Name System (DNS) Extensions", RFC 5205, April 2008. [RFC4282] Aboba, B., Beadles, M., Arkko, J., and P. Eronen, "The Network Access Identifier", RFC 4282, November 2005. [RFC2459] Internet X.509 Public Key Infrastructure: Certificate and CRL Profile January 1999. [RFC5203] Laganier, J., Koponen, T., and L. Eggert, "Host Identity Protocol (HIP) Registration Extension", RFC 5203, April 2008. Zhang and Xu. Expires November 27, 2009 [Page 9] Internet-Draft Extensions of HIP with Hierarchical Information May 2009 Authors' Addresses Dacheng Zhang Huawei Technologies Co.,Ltd KuiKe Building, No.9 Xinxi Rd., Hai-Dian District Beijing, 100085 P.R. China Email: zhangdacheng@huawei.com Xiaohu Xu Huawei Technologies Co.,Ltd KuiKe Building, No.9 Xinxi Rd., Hai-Dian District Beijing, 100085 P.R. China Email: xuxh@huawei.com Zhang and Xu. Expires November 27, 2009 [Page 10]