--- 1/draft-ietf-hip-dns-08.txt 2007-04-13 22:12:07.000000000 +0200 +++ 2/draft-ietf-hip-dns-09.txt 2007-04-13 22:12:07.000000000 +0200 @@ -1,19 +1,19 @@ Network Working Group P. Nikander Internet-Draft Ericsson Research Nomadic Lab -Expires: April 20, 2007 J. Laganier - DoCoMo Euro-Labs - October 17, 2006 +Intended status: Experimental J. Laganier +Expires: October 15, 2007 DoCoMo Euro-Labs + April 13, 2007 Host Identity Protocol (HIP) Domain Name System (DNS) Extensions - draft-ietf-hip-dns-08 + draft-ietf-hip-dns-09 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 @@ -24,44 +24,44 @@ 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 April 20, 2007. + This Internet-Draft will expire on October 15, 2007. Copyright Notice - Copyright (C) The Internet Society (2006). + Copyright (C) The IETF Trust (2007). Abstract This document specifies a new resource record (RR) for the Domain Name System (DNS), and how to use it with the Host Identity Protocol - (HIP.) This RR allows a HIP node to store in the DNS its Host + (HIP). This RR allows a HIP node to store in the DNS its Host Identity (HI, the public component of the node public-private key pair), Host Identity Tag (HIT, a truncated hash of its public key), - and the Domain Names of its rendezvous servers (RVS.) + and the Domain Names of its rendezvous servers (RVS). Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Conventions used in this document . . . . . . . . . . . . . . 4 3. Usage Scenarios . . . . . . . . . . . . . . . . . . . . . . . 5 3.1. Simple static singly homed end-host . . . . . . . . . . . 6 3.2. Mobile end-host . . . . . . . . . . . . . . . . . . . . . 7 4. Overview of using the DNS with HIP . . . . . . . . . . . . . . 9 - 4.1. Storing HI, HIT and RVS in DNS . . . . . . . . . . . . . . 9 + 4.1. Storing HI, HIT and RVS in the DNS . . . . . . . . . . . . 9 4.2. Initiating connections based on DNS names . . . . . . . . 9 5. HIP RR Storage Format . . . . . . . . . . . . . . . . . . . . 10 5.1. HIT length format . . . . . . . . . . . . . . . . . . . . 10 5.2. PK algorithm format . . . . . . . . . . . . . . . . . . . 10 5.3. PK length format . . . . . . . . . . . . . . . . . . . . . 11 5.4. HIT format . . . . . . . . . . . . . . . . . . . . . . . . 11 5.5. Public key format . . . . . . . . . . . . . . . . . . . . 11 5.6. Rendezvous servers format . . . . . . . . . . . . . . . . 11 6. HIP RR Presentation Format . . . . . . . . . . . . . . . . . . 12 7. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 @@ -77,148 +77,155 @@ Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 20 Intellectual Property and Copyright Statements . . . . . . . . . . 21 1. Introduction This document specifies a new resource record (RR) for the Domain Name System (DNS) [RFC1034], and how to use it with the Host Identity Protocol (HIP) [I-D.ietf-hip-base]. This RR allows a HIP node to store in the DNS its Host Identity (HI, the public component of the node public-private key pair), Host Identity Tag (HIT, a truncated - hash of its HI), and the Domain Names of its rendezvous servers - (RVS.) [I-D.ietf-hip-rvs] + hash of its HI), and the Domain Names of its rendezvous servers (RVS) + [I-D.ietf-hip-rvs]. Currently, most of the Internet applications that need to communicate with a remote host first translate a domain name (often obtained via user input) into one or more IP address(es). This step occurs prior to communication with the remote host, and relies on a DNS lookup. With HIP, IP addresses are intended to be used mostly for on-the-wire - communication between end hosts, while most ULPs and applications use - HIs or HITs instead (ICMP might be an example of an ULP not using - them.) Consequently, we need a means to translate a domain name into - an HI. Using the DNS for this translation is pretty straightforward: - We define a new HIP resource record. Upon query by an application or - ULP for a FQDN -> IP lookup, the resolver would then additionally - perform an FQDN -> HI lookup, and use it to construct the resulting - HI -> IP mapping (which is internal to the HIP layer.) The HIP layer - uses the HI -> IP mapping to translate HIs and HITs into IP addresses + communication between end hosts, while most Upper Layer Protocols + (ULP) and applications use HIs or HITs instead (ICMP might be an + example of an ULP not using them). Consequently, we need a means to + translate a domain name into an HI. Using the DNS for this + translation is pretty straightforward: We define a new HIP resource + record. Upon query by an application or ULP for a name to IP address + lookup, the resolver would then additionally perform a name to HI + lookup, and use it to construct the resulting HI to IP address + mapping (which is internal to the HIP layer). The HIP layer uses the + HI to IP address mapping to translate HIs and HITs into IP addresses and vice versa. The HIP rendezvous extensions [I-D.ietf-hip-rvs] proposal allows a HIP node to be reached via the IP address(es) of a third party, the - node's rendezvous server (RVS.) An initiator willing to establish a + node's rendezvous server (RVS). An initiator willing to establish a HIP association with a responder served by a RVS would typically initiate a HIP exchange by sending an I1 towards the RVS IP address rather than towards the responder IP address. Consequently, we need - a means to translate a domain name into the rendezvous server's - domain name. + a means to to find the name of a rendezvous server for a given host + name. - This draft introduces the new HIP DNS Resource Record to store + This document introduces the new HIP DNS Resource Record to store Rendezvous Server (RVS), Host Identity (HI) and Host Identity Tag (HIT) information. 2. 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 RFC2119 [RFC2119]. 3. Usage Scenarios In this section, we briefly introduce a number of usage scenarios where the DNS is useful with the Host Identity Protocol. With HIP, most application and ULPs are unaware of the IP addresses used to carry packets on the wire. Consequently, a HIP node could take advantage of having multiple IP addresses for fail-over, redundancy, mobility, or renumbering, in a manner which is transparent to most ULPs and applications (because they are bound to - HIs, hence they are agnostic to these IP address changes.) + HIs, hence they are agnostic to these IP address changes). - In these situations, a node wishing to be reachable by reference to - its FQDN should store the following information in the DNS: + In these situations, for a node to be reachable by reference to its + Fully Qualified Domain Name (FQDN), the following information should + be stored in the DNS: - o A set of IP address(es) through A [RFC1035] and AAAA [RFC3596] - RRs. + o A set of IP address(es) through A [RFC1035] and AAAA [RFC3596] RR + sets (RRSets [RFC2181]). o A Host Identity (HI), Host Identity Tag (HIT) and possibly a set - of rendezvous server(s) (RVS) through HIP RRs. + of rendezvous servers (RVS) through HIP RRs. When a HIP node wants to initiate a communication with another HIP - node, it first needs to perform a HIP base exchange to set-up a HIP + node, it first needs to perform a HIP base exchange to set up a HIP association towards its peer. Although such an exchange can be initiated opportunistically, i.e., without prior knowledge of the responder's HI, by doing so both nodes knowingly risk man-in-the- middle attacks on the HIP exchange. To prevent these attacks, it is recommended that the initiator first obtain the HI of the responder, and then initiate the exchange. This can be done, for example, through manual configuration or DNS lookups. Hence, a new HIP RR is introduced. When a HIP node is frequently changing its IP address(es), the - dynamic DNS update latency may prevent it from publishing its new IP - address(es) in the DNS. For solving this problem, the HIP - architecture [RFC4423] introduces rendezvous servers (RVS.) A HIP - host uses a rendezvous server as a rendezvous point, to maintain - reachability with possible HIP initiators while moving + natural DNS latency for propagating changes may prevent it from + publishing its new IP address(es) in the DNS. For solving this + problem, the HIP architecture [RFC4423] introduces rendezvous servers + (RVS). A HIP host uses a rendezvous server as a rendezvous point, to + maintain reachability with possible HIP initiators while moving [I-D.ietf-hip-mm]. Such a HIP node would publish in the DNS its RVS domain name(s) in a HIP RR, while keeping its RVS up-to-date with its current set of IP addresses. When a HIP node wants to initiate a HIP exchange with a responder it will perform a number of DNS lookups. Depending on the type of the implementation, the order in which those lookups will be issued may - vary. For instance, implementations using HIT in APIS may typically + vary. For instance, implementations using HIT in APIs may typically first query for HIP resource records at the responder FQDN, while those using IP address in APIs may typically first query for A and/or AAAA resource records. In the following we assume that the initiator first queries for HIP resource records at the responder FQDN. If the query for the HIP type was responded to with a DNS answer with RCODE=3 (Name Error), then the responder's information is not present - in the DNS and further queries SHOULD NOT be made. + in the DNS and further queries for the same owner name SHOULD NOT be + made. In case the query for the HIP records returned a DNS answer with - RCODE=0 (No Error), then the initiator sends out one more query for - for A and AAAA types at the responder's FQDN. + RCODE=0 (No Error) and an empty answer section, it means that no HIP + information is avalaible at the responder name. In such a case, if + the initiator has been configured with a policy to fallback to + opportunistic HIP (initiating without knowing the responder's HI) or + plain IP, it would sends out more queries for A and AAAA types at the + responder's FQDN. - Depending on the combinations of answer the situations described in + Depending on the combinations of answers the situations described in Section 3.1 and Section 3.2 can occur. Note that storing HIP RR information in the DNS at a FQDN which is assigned to a non-HIP node might have ill effects on its reachability by HIP nodes. 3.1. Simple static singly homed end-host A HIP node (R) with a single static network attachment, wishing to be reachable by reference to its FQDN (www.example.com), would store in the DNS, in addition to its IP address(es) (IP-R), its Host Identity (HI-R) and Host Identity Tag (HIT-R) in a HIP resource record. An initiator willing to associate with a node would typically issue the following queries: - QNAME=www.example.com, QTYPE=HIP + o QNAME=www.example.com, QTYPE=HIP - (QCLASS=IN is assumed and omitted from the examples) + o (QCLASS=IN is assumed and omitted from the examples) Which returns a DNS packet with RCODE=0 and one or more HIP RRs with the HIT and HI (e.g. HIT-R and HI-R) of the responder in the answer section, but no RVS. - QNAME=www.example.com, QTYPE=A + o QNAME=www.example.com, QTYPE=A QNAME=www.example.com, QTYPE=AAAA - Which returns a DNS packet with RCODE=0 and one or more A or AAAA RRs + Which returns DNS packets with RCODE=0 and one or more A or AAAA RRs containing IP address(es) of the responder (e.g. IP-R) in the answer section. Caption: In the remainder of this document, for the sake of keeping diagrams simple and concise, several DNS queries and answers are represented as one single transaction, while in fact there are several queries and answers flowing back and forth, as described in the textual examples. [HIP? A? ] @@ -231,44 +238,46 @@ | | [HIP HIT-R HI-R ] | | [A IP-R ] | v +-----+ +-----+ | |--------------I1------------->| | | I |<-------------R1--------------| R | | |--------------I2------------->| | | |<-------------R2--------------| | +-----+ +-----+ + Static Singly Homed Host + The initiator would then send an I1 to the responder's IP addresses - (IP-R.) + (IP-R). 3.2. Mobile end-host A mobile HIP node (R) wishing to be reachable by reference to its FQDN (www.example.com) would store in the DNS, possibly in addition to its IP address(es) (IP-R), its HI (HI-R), HIT (HIT-R) and the - domain name(s) of its rendezvous server(s) (rvs.example.com) in HIP - resource record(s). The mobile HIP node also needs to notify its + domain name(s) of its rendezvous server(s) (e.g. rvs.example.com) in + HIP resource record(s). The mobile HIP node also needs to notify its rendezvous servers of any change in its set of IP address(es). An initiator willing to associate with such mobile node would typically issue the following queries: - QNAME=www.example.com, QTYPE=HIP + o QNAME=www.example.com, QTYPE=HIP Which returns a DNS packet with RCODE=0 and one or more HIP RRs with the HIT, HI and RVS domain name(s) (e.g. HIT-R, HI-R, and rvs.example.com) of the responder in the answer section. - QNAME=rvs.example.com, QTYPE=A + o QNAME=rvs.example.com, QTYPE=A QNAME=www.example.com, QTYPE=AAAA - Which returns a DNS packet with RCODE=0 and one or more A or AAAA RRs + Which returns DNS packets with RCODE=0 and one or more A or AAAA RRs containing IP address(es) of the responder's RVS (e.g. IP-RVS) in the answer section. [HIP? ] [www.example.com] [A? ] [rvs.example.com] +-----+ +----------------------------------------->| | | | DNS | @@ -286,70 +295,72 @@ | | | +-----+ | | | | | | | | | | v | v +-----+ +-----+ | |<---------------R1------------| | | I |----------------I2----------->| R | | |<---------------R2------------| | +-----+ +-----+ - The initiator would then send an I1 to the RVS IP address (IP-RVS.) + Mobile End-Host + + The initiator would then send an I1 to the RVS IP address (IP-RVS). Following, the RVS will relay the I1 up to the mobile node's IP address (IP-R), which will complete the HIP exchange. 4. Overview of using the DNS with HIP -4.1. Storing HI, HIT and RVS in DNS +4.1. Storing HI, HIT and RVS in the DNS - Any conforming implementation may store a Host Identity (HI) and its - associated Host Identity Tag (HIT) in a DNS HIP RDATA format. If a - particular form of an HI does not already have a specified RDATA - format, a new RDATA-like format SHOULD be defined for the HI. HI and - HIT are defined in Section 3 of [I-D.ietf-hip-base]. + For any HIP node its Host Identity (HI), the associated Host Identity + Tag (HIT), and the FQDN of its possible RVSs can be stored in a DNS + HIP RR. Any conforming implementation may store a Host Identity (HI) + and its associated Host Identity Tag (HIT) in a DNS HIP RDATA format. + HI and HIT are defined in Section 3 of [I-D.ietf-hip-base]. Upon return of a HIP RR, a host MUST always calculate the HI- derivative HIT to be used in the HIP exchange, as specified in Section 3 of the HIP base specification [I-D.ietf-hip-base], while the HIT possibly embedded along SHOULD only be used as an - optimization (e.g. table lookup.) + optimization (e.g. table lookup). The HIP resource record may also contain one or more domain name(s) of rendezvous server(s) towards which HIP I1 packets might be sent to trigger the establishment of an association with the entity named by this resource record [I-D.ietf-hip-rvs]. The rendezvous server field of the HIP resource record stored at a - given domain name MAY include the domain name itself. A semantically - equivalent situation occurs if no rendezvous server is stored in the - HIP resource record of that domain. Such situations occurs in two - cases: + given owner name MAY include the owner name itself. A semantically + equivalent situation occurs if no rendezvous server is present in the + HIP resource record stored at that owner name. Such situations + occurs in two cases: o The host is mobile, and the A and/or AAAA resource record(s) - stored at its domain name contains the IP address(es) of its + stored at its host name contains the IP address(es) of its rendezvous server rather than its own one. o The host is stationary, and can be reached directly at IP address(es) contained in A and/or AAAA resource record(s) stored - at its domain name. This a degenerated case of rendezvous service + at its host name. This a degenerated case of rendezvous service where the host somewhat acts as a rendezvous server for itself. An RVS receiving such an I1 would then relay it to the appropriate - responder (the owner of the I1 receiver HIT.) The responder will + responder (the owner of the I1 receiver HIT). The responder will then complete the exchange with the initiator, typically without ongoing help from the RVS. 4.2. Initiating connections based on DNS names On a HIP node, a Host Identity Protocol exchange SHOULD be initiated - whenever an Upper Layer Protocol attempts to communicate with an - entity and the DNS lookup returns HIP resource records. + whenever an ULP attempts to communicate with an entity and the DNS + lookup returns HIP resource records. 5. HIP RR Storage Format The RDATA for a HIP RR consists of a public key algorithm type, the HIT length, a HIT, a public key, and optionally one or more rendezvous server(s). 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ @@ -380,230 +391,233 @@ 5.1. HIT length format The HIT length indicates the length in bytes of the HIT field. This is an 8 bits unsigned integer. 5.2. PK algorithm format The PK algorithm field indicates the public key cryptographic algorithm and the implied public key field format. This is an 8 bits unsigned integer. This document reuses the values defined for the - 'algorithm type' of the IPSECKEY RR [RFC4025] 'gateway type' field. - - The presently defined values are shown here for reference: - - 1 A DSA key is present, in the format defined in RFC2536 - [RFC2536]. + 'algorithm type' of the IPSECKEY RR [RFC4025]. - 2 A RSA key is present, in the format defined in RFC3110 - [RFC3110]. + Presently defined values are listed in Section 9 for reference. 5.3. PK length format The PK length indicates the length in bytes of the Public key field. This is a 16 bits unsigned integer in network byte order. 5.4. HIT format The HIT is stored, as a binary value, in network byte order. 5.5. Public key format Both of the public key types defined in this document (RSA and DSA) - reuse the public key formats defined for the IPSECKEY RR [RFC4025] - (which in turns contains the algorithm-specific portion of the KEY RR - RDATA, all of the KEY RR DATA after the first four octets, - corresponding to the same portion of the KEY RR that must be - specified by documents that define a DNSSEC algorithm.) - - In the future, if a new algorithm is to be used both by IPSECKEY RR - and HIP RR, it should use the same public key encoding for both RRs. - Unless specified otherwise, the HIP RR public key field SHOULD use - the same public key format as the IPSECKEY RR RDATA for the - corresponding algorithm. + reuse the public key formats defined for the IPSECKEY RR [RFC4025]. The DSA key format is defined in RFC2536 [RFC2536]. The RSA key format is defined in RFC3110 [RFC3110] and the RSA key size limit (4096 bits) is relaxed in the IPSECKEY RR [RFC4025] specification. 5.6. Rendezvous servers format The Rendezvous servers field indicates one or more variable length - wire-encoded domain names rendezvous server(s), as described in + wire-encoded domain names of rendezvous server(s), as described in Section 3.3 of RFC1035 [RFC1035]. The wire-encoded format is self- describing, so the length is implicit. The domain names MUST NOT be compressed. The rendezvous server(s) are listed in order of - preference (i.e. first rendezvous server(s) are preferred). + preference (i.e. first rendezvous server(s) are preferred), defining + an implicit order amongst rendezvous server of a single RR. When + multiple HIP RRs are present at the same owner name, this implicit + order of rendezvous servers within an RR MUST NOT be used to infer a + preference order between rendezvous servers stored in different RRs. 6. HIP RR Presentation Format This section specifies the representation of the HIP RR in a zone - data master file. + master file. The HIT length field is not represented as it is implicitly known thanks to the HIT field representation. The PK algorithm field is represented as unsigned integers. - The PK length field is not represented as it is implicitly known - thanks to the Public key field representation. - The HIT field is represented as the Base16 encoding [RFC4648] (a.k.a. hex or hexadecimal) of the HIT. The encoding MUST NOT contain - whitespace(s). + whitespaces to be able to distinguish it from the public key field. The Public Key field is represented as the Base64 encoding [RFC4648] - of the public key. The encoding MAY contain whitespace(s), and such - whitespace(s) MUST be ignored. + of the public key. The encoding MUST NOT contain whitespace(s) to be + able to distinguish from the Rendezvous Servers field. - The Rendezvous servers field is represented by one or more - uncompressed domain name(s) + The PK length field is not represented as it is implicitly known + thanks to the Public key field representation containing no + whitespaces. + + The Rendezvous Servers field is represented by one or more domain + name(s) separated by whitespace(s). The complete representation of the HPIHI record is: IN HIP ( pk-algorithm base16-encoded-hit base64-encoded-public-key rendezvous-server[1] ... rendezvous-server[n] ) + When no RVS are present, the representation of the HPIHI record is: + + IN HIP ( pk-algorithm + base16-encoded-hit + base64-encoded-public-key ) + 7. Examples + In the examples below, the public key field containing no whitespace + is wrapped since it does not fit in a single line of this document. + Example of a node with HI and HIT but no RVS: - www.example.com. IN HIP ( 2 4009D9BA7B1A74DF365639CC39F1D578 - AwEAAbdxyhNuSutc5EMzxTs9LBPCIkOFH8cIv - M4p9+LrV4e19WzK00+CI6zBCQTdtWsuxKbWIy - 87UOoJTwkUs7lBu+Upr1gsNrut79ryra+bSRG - Qb1slImA8YVJyuIDsj7kwzG7jnERNqnWxZ48A - WkskmdHaVDP4BcelrTI3rMXdXF5D ) +www.example.com. IN HIP ( 2 200100107B1A74DF365639CC39F1D578 + AwEAAbdxyhNuSutc5EMzxTs9LBPCIkOFH8cIvM4p +9+LrV4e19WzK00+CI6zBCQTdtWsuxKbWIy87UOoJTwkUs7lBu+Upr1gsNrut79ryra+bSRGQ +b1slImA8YVJyuIDsj7kwzG7jnERNqnWxZ48AWkskmdHaVDP4BcelrTI3rMXdXF5D ) Example of a node with a HI, HIT and one RVS: - www.example.com. IN HIP ( 2 4009D9BA7B1A74DF365639CC39F1D578 - AwEAAbdxyhNuSutc5EMzxTs9LBPCIkOFH8cIv - M4p9+LrV4e19WzK00+CI6zBCQTdtWsuxKbWIy - 87UOoJTwkUs7lBu+Upr1gsNrut79ryra+bSRG - Qb1slImA8YVJyuIDsj7kwzG7jnERNqnWxZ48A - WkskmdHaVDP4BcelrTI3rMXdXF5D - rvs.example.com ) +www.example.com. IN HIP ( 2 200100107B1A74DF365639CC39F1D578 + AwEAAbdxyhNuSutc5EMzxTs9LBPCIkOFH8cIvM4p +9+LrV4e19WzK00+CI6zBCQTdtWsuxKbWIy87UOoJTwkUs7lBu+Upr1gsNrut79ryra+bSRGQ +b1slImA8YVJyuIDsj7kwzG7jnERNqnWxZ48AWkskmdHaVDP4BcelrTI3rMXdXF5D + rvs.example.com. ) Example of a node with a HI, HIT and two RVS: - www.example.com. IN HIP ( 2 4009D9BA7B1A74DF365639CC39F1D578 - AwEAAbdxyhNuSutc5EMzxTs9LBPCIkOFH8cIv - M4p9+LrV4e19WzK00+CI6zBCQTdtWsuxKbWIy - 87UOoJTwkUs7lBu+Upr1gsNrut79ryra+bSRG - Qb1slImA8YVJyuIDsj7kwzG7jnERNqnWxZ48A - WkskmdHaVDP4BcelrTI3rMXdXF5D - rvs1.example.com - rvs2.example.com ) +www.example.com. IN HIP ( 2 200100107B1A74DF365639CC39F1D578 + AwEAAbdxyhNuSutc5EMzxTs9LBPCIkOFH8cIvM4p +9+LrV4e19WzK00+CI6zBCQTdtWsuxKbWIy87UOoJTwkUs7lBu+Upr1gsNrut79ryra+bSRGQ +b1slImA8YVJyuIDsj7kwzG7jnERNqnWxZ48AWkskmdHaVDP4BcelrTI3rMXdXF5D + rvs1.example.com. + rvs2.example.com. ) 8. Security Considerations - Though the security considerations of the HIP DNS extensions still - need to be more investigated and documented, this section contains a - description of the known threats involved with the usage of the HIP - DNS extensions. + This section contains a description of the known threats involved + with the usage of the HIP DNS extensions. In a manner similar to the IPSECKEY RR [RFC4025], the HIP DNS Extensions allows to provision two HIP nodes with the public keying material (HI) of their peer. These HIs will be subsequently used in a key exchange between the peers. Hence, the HIP DNS Extensions introduce the same kind of threats that IPSECKEY does, plus threats caused by the possibility given to a HIP node to initiate or accept a HIP exchange using "opportunistic" or "unpublished initiator HI" modes. A HIP node SHOULD obtain HIP RRs from a trusted party trough a secure - channel insuring proper data integrity of the RRs. DNSSEC [RFC4033] - [RFC4034] [RFC4035] provides such a secure channel. + channel insuring data integrity and authenticity of the RRs. DNSSEC + [RFC4033] [RFC4034] [RFC4035] provides such a secure channel. + However, it should be emphasized that DNSSEC does only offer data + integrity and authenticty guarantees to the channel between the DNS + server publishing a zone and the HIP node. DNSSEC does not ensure + that the entity publishing the zone is trusted. Therefore, the RRSIG + signature of the HIP RRSet MUST NOT be misinterpreted as a + certificate binding the HI and/or the HIT to the owner name. In the absence of a proper secure channel, both parties are vulnerable to MitM and DoS attacks, and unrelated parties might be subject to DoS attacks as well. These threats are described in the following sections. 8.1. Attacker tampering with an insecure HIP RR The HIP RR contains public keying material in the form of the named - peer's public key (the HI) and its secure hash (the HIT.) Both of + peer's public key (the HI) and its secure hash (the HIT). Both of these are not sensitive to attacks where an adversary gains knowledge of them. However, an attacker that is able to mount an active attack on the DNS, i.e., tampers with this HIP RR (e.g. using DNS spoofing) is able to mount Man-in-the-Middle attacks on the cryptographic core of the eventual HIP exchange (responder's HIP RR rewritten by the - attacker.) + attacker). The HIP RR may contain a rendezvous server domain name resolved into a destination IP address where the named peer is reachable by an I1 - (HIP Rendezvous Extensions IPSECKEY RR [I-D.ietf-hip-rvs].) Thus, an + (HIP Rendezvous Extensions IPSECKEY RR [I-D.ietf-hip-rvs]). Thus, an attacker able to tamper with this RR is able to redirect I1 packets sent to the named peer to a chosen IP address, for DoS or MitM attacks. Note that this kind of attack is not specific to HIP and - exists independently to whether or not HIP and the HIP RR are used. + exists independently of whether or not HIP and the HIP RR are used. Such an attacker might tamper with A and AAAA RRs as well. An attacker might obviously use these two attacks in conjunction: It - will replace the responder's HI and RVS IP address by its owns in a + will replace the responder's HI and RVS IP address by its own in a spoofed DNS packet sent to the initiator HI, then redirect all exchanged packets to him and mount a MitM on HIP. In this case HIP won't provide confidentiality nor initiator HI protection from eavesdroppers. 8.2. Hash and HITs Collisions - As many cryptographic algorithm, some secure hashes (e.g. SHA1, used - by HIP to generate a HIT from an HI) eventually become insecure, + As many cryptographic algorithms, some secure hashes (e.g. SHA1, + used by HIP to generate a HIT from an HI) eventually become insecure, because an exploit has been found in which an attacker with a reasonable computation power breaks one of the security features of - the hash (e.g. its supposed collision resistance.) This is why a HIP + the hash (e.g. its supposed collision resistance). This is why a HIP end-node implementation SHOULD NOT authenticate its HIP peers based - solely on a HIT retrieved from DNS, but SHOULD rather use HI-based - authentication. + solely on a HIT retrieved from the DNS, but SHOULD rather use HI- + based authentication. 8.3. DNSSEC In the absence of DNSSEC, the HIP RR is subject to the threats described in RFC 3833 [RFC3833]. 9. IANA Considerations IANA should allocate one new RR type code (TBD, 55?) for the HIP RR from the standard RR type space. IANA does not need to open a new registry for public key algorithms of the HIP RR because the HIP RR reuses "algorithms types" defined - for the IPSECKEY RR [RFC4025]. The presently defined values are - shown here for reference: + for the IPSECKEY RR [RFC4025]. Presently defined values are shown + here for reference only: 0 is reserved 1 is RSA 2 is DSA + In the future, if a new algorithm is to be used for the HIP RR, a new + algorithm type and corresponding public key encoding should be + defined for the IPSECKEY RR. The HIP RR should reuse both the same + algorithm type and the same corresponding public key format as the + IPSECKEY RR. + 10. Acknowledgments As usual in the IETF, this document is the result of a collaboration between many people. The authors would like to thanks the author (Michael Richardson), contributors and reviewers of the IPSECKEY RR [RFC4025] specification, which this document was framed after. The authors would also like to thanks the following people, who have provided thoughtful and helpful discussions and/or suggestions, that have helped improving this document: Jeff Ahrenholz, Rob Austein, - Hannu Flinck, Tom Henderson, Olaf Kolkman, Miika Komu, Andrew - McGregor, Erik Nordmark, and Gabriel Montenegro. Some parts of this - draft stem from [I-D.ietf-hip-base]. + Hannu Flinck, Olafur Gu[eth]mundsson, Tom Henderson, Peter Koch, Olaf + Kolkman, Miika Komu, Andrew McGregor, Erik Nordmark, and Gabriel + Montenegro. Some parts of this document stem from + [I-D.ietf-hip-base]. Julien Laganier is partly funded by Ambient Networks, a research project supported by the European Commission under its Sixth Framework Program. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of the Ambient Networks project or the European Commission. 11. References @@ -612,25 +626,22 @@ [RFC1034] Mockapetris, P., "Domain names - concepts and facilities", STD 13, RFC 1034, November 1987. [RFC1035] Mockapetris, P., "Domain names - implementation and specification", STD 13, RFC 1035, November 1987. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. - [RFC2536] Eastlake, D., "DSA KEYs and SIGs in the Domain Name System - (DNS)", RFC 2536, March 1999. - - [RFC3110] Eastlake, D., "RSA/SHA-1 SIGs and RSA KEYs in the Domain - Name System (DNS)", RFC 3110, May 2001. + [RFC2181] Elz, R. and R. Bush, "Clarifications to the DNS + Specification", RFC 2181, July 1997. [RFC3596] Thomson, S., Huitema, C., Ksinant, V., and M. Souissi, "DNS Extensions to Support IP Version 6", RFC 3596, October 2003. [RFC4025] Richardson, M., "A Method for Storing IPsec Keying Material in DNS", RFC 4025, March 2005. [RFC4033] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose, "DNS Security Introduction and Requirements", @@ -642,36 +653,42 @@ [RFC4035] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose, "Protocol Modifications for the DNS Security Extensions", RFC 4035, March 2005. [RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data Encodings", RFC 4648, October 2006. [I-D.ietf-hip-base] Moskowitz, R., "Host Identity Protocol", - draft-ietf-hip-base-06 (work in progress), June 2006. + draft-ietf-hip-base-07 (work in progress), February 2007. [I-D.ietf-hip-rvs] Laganier, J. and L. Eggert, "Host Identity Protocol (HIP) Rendezvous Extension", draft-ietf-hip-rvs-05 (work in progress), June 2006. 11.2. Informative references + [RFC2536] Eastlake, D., "DSA KEYs and SIGs in the Domain Name System + (DNS)", RFC 2536, March 1999. + + [RFC3110] Eastlake, D., "RSA/SHA-1 SIGs and RSA KEYs in the Domain + Name System (DNS)", RFC 3110, May 2001. + [RFC4423] Moskowitz, R. and P. Nikander, "Host Identity Protocol (HIP) Architecture", RFC 4423, May 2006. [I-D.ietf-hip-mm] - Nikander, P., "End-Host Mobility and Multihoming with the - Host Identity Protocol", draft-ietf-hip-mm-04 (work in - progress), June 2006. + Henderson, T., "End-Host Mobility and Multihoming with the + Host Identity Protocol", draft-ietf-hip-mm-05 (work in + progress), March 2007. [RFC3833] Atkins, D. and R. Austein, "Threat Analysis of the Domain Name System (DNS)", RFC 3833, August 2004. Authors' Addresses Pekka Nikander Ericsson Research Nomadic Lab JORVAS FIN-02420 FINLAND @@ -682,21 +699,37 @@ Julien Laganier DoCoMo Communications Laboratories Europe GmbH Landsberger Strasse 312 Munich 80687 Germany Phone: +49 89 56824 231 Email: julien.ietf@laposte.net URI: http://www.docomolab-euro.com/ -Intellectual Property Statement +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. + +Intellectual Property The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. @@ -706,30 +739,14 @@ such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. 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. -Disclaimer of Validity - - 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 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. - -Copyright Statement - - Copyright (C) The Internet Society (2006). 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. - Acknowledgment - Funding for the RFC Editor function is currently provided by the - Internet Society. + Funding for the RFC Editor function is provided by the IETF + Administrative Support Activity (IASA).