--- 1/draft-ietf-hip-cert-04.txt 2010-11-08 13:16:13.000000000 +0100 +++ 2/draft-ietf-hip-cert-05.txt 2010-11-08 13:16:13.000000000 +0100 @@ -1,40 +1,34 @@ Host Identity Protocol Heer Internet-Draft Distributed Systems Group, RWTH Intended status: Experimental Aachen University -Expires: March 27, 2011 Varjonen +Expires: May 12, 2011 Varjonen Helsinki Institute for Information Technology - September 23, 2010 + November 8, 2010 - HIP Certificates - draft-ietf-hip-cert-04 + Host Identity Protocol Certificates + draft-ietf-hip-cert-05 Abstract The CERT parameter is a container for X.509.v3 certificates and Simple Public Key Infrastructure (SPKI) certificates. It is used for - carrying these certificates in HIP control packets. This document - only specifies the certificate parameter and the error signaling in - case of a failed verification. The use of certificates including how - certificates are obtained, requested, and which actions are taken - upon successful or failed verification are to be defined in the - documents that use the certificate parameter. Additionally, this - document specifies the representations of Host Identity Tags in - X.509.v3 and SPKI certificates. - -Requirements Language - - 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]. + carrying these certificates in Host Identity Protocol (HIP) control + packets. This document only specifies the certificate parameter and + the error signaling in case of a failed verification. The use of + certificates including how certificates are obtained, requested, and + which actions are taken upon successful or failed verification are to + be defined in the documents that use the certificate parameter. + Additionally, this document specifies the representations of Host + Identity Tags in X.509.v3 and SPKI certificates. Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. This document may not be modified, and derivative works of it may not be created, except to format it for publication as an RFC or to translate it into languages other than English. Internet-Drafts are working documents of the Internet Engineering @@ -39,27 +33,28 @@ 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 March 27, 2011. + This Internet-Draft will expire on May 12, 2011. Copyright Notice Copyright (c) 2010 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 (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents @@ -74,20 +69,26 @@ Digital certificates bind a piece of information to a public key by means of a digital signature, and thus, enable the holder of a private key to generate cryptographically verifiable statements. The Host Identity Protocol (HIP) [RFC5201] defines a new cryptographic namespace based on asymmetric cryptography. The identity of each host is derived from a public key, allowing hosts to digitally sign data with their private key. This document specifies the CERT parameter, which is used to transmit digital certificates in HIP. It fills the placeholder specified in Section 5.2 of [RFC5201]. +1.1. Requirements Language + + 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]. + 2. CERT Parameter The CERT parameter is a container for certain types of digital certificates. It MAY either carry SPKI certificates or X.509.v3 certificates. It does not specify any certificate semantics. However, it defines supplementary parameters that help HIP hosts to transmit semantically grouped CERT parameters in a more systematic way. The specific use of the CERT parameter for different use cases is intentionally not discussed in this document. @@ -135,21 +136,21 @@ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / | Padding | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type 768 Length Length in octets, excluding Type, Length, and Padding Cert group Group ID grouping multiple related CERT parameters Cert count Total count of certificates that are sent, possibly in several consecutive HIP control packets. Cert ID The sequence number for this certificate - Cert Type Describes the type of the certificate + Cert Type Indicates the type of the certificate Padding Any Padding, if necessary, to make the TLV a multiple of 8 bytes. The following certificate types are defined: +--------------------------------+-------------+ | Cert format | Type number | +--------------------------------+-------------+ | X.509.v3 | 1 | | SPKI | 2 | @@ -160,84 +161,86 @@ | Distinguished Name of X.509.v3 | 7 | | Distinguished Name of SPKI | 8 | +--------------------------------+-------------+ The next sections outline the use of HITs in X.509.v3 and in SPKI certificates. X.509.v3 certificates are defined in [RFC3280]. The wire format for X.509.v3 is Distinguished Encoding Rules format as defined in [X.690]. The SPKI and its formats are defined in [RFC2693]. - Hash and URL encodings (3 to 4) are used as defined in [RFC4306] + Hash and URL encodings (3 and 4) are used as defined in [RFC4306] Section 3.6. Using hash and URL encodings results in smaller HIP control packets, but requires the receiver to resolve the URL or check a local cache against the hash. LDAP URL encodings (5 and 6) are used as defined in [RFC2255]. Using LDAP URL encoding results in smaller HIP control packets but requires the receiver to retrieve the certificate or check a local cache against the URL. Distinguished name (DN) encodings (7 and 8) are used as defined in [RFC1779]. Using the DN encoding results in smaller HIP control packets, but requires the receiver to retrieve the certificate or check a local cache against the DN. 3. X.509.v3 Certificate Object and Host Identities When using X.509.v3 certificates to transmit information related to HIP hosts, HITs MAY be enclosed within the certificates. HITs can represent an issuer, a subject, or both. In X.509.v3 HITs are - represented as issuer and subject alternative name extensions as - defined in [RFC2459]. If only HIP information is presented as either - the issuer or the subject the HIT is also placed into the respective - entity's DNs Common Name (CN) section in a colon delimited - presentation format. Inclusion of CN is not necessary if DN contains - any other information. It is RECOMMENDED to use the FQDN/NAI from - the hosts HOST_ID parameter in the DN if one exists. The full HIs - are presented in the public key entries of X.509.v3 certificates. + represented as issuer or subject alternative name extensions as + defined in [RFC2459]. If only HIT of the host is presented as either + the issuer or the subject the respective HIT MUST be placed into the + respective entity's DN's Common Name (CN) section in a colon + delimited presentation format defined in [RFC5952]. Inclusion of CN + is not necessary if DN contains any other naming information. It is + RECOMMENDED to use the FQDN/NAI from the hosts HOST_ID parameter in + the DN if one exists. The full HIs are presented in the public key + entries of X.509.v3 certificates. - The following example illustrates a case in which the issuer and the - subject are both HIP enabled. + The following examples illustrate how HITs are presented as issuer + and subject in the DN and in the X.509.v3 extension alternative + names. - Format: - Issuer: CN=hit-of-host - Subject: CN=hit-of-host + Format of DN: + Issuer: CN=hit-of-issuer + Subject: CN=hit-of-issuer - X509v3 extensions: + Example DN: + Issuer: CN=2001:14:6cf:fae7:bb79:bf78:7d64:c056 + Subject: CN=2001:1c:5a14:26de:a07c:385b:de35:60e3 + + Format of X509v3 extensions: X509v3 Issuer Alternative Name: - IP Address:HIT-OF-HOST + IP Address:HIT-OF-ISSUER X509v3 Subject Alternative Name: - IP Address:HIT-OF-HOST - - Example: - Issuer: CN=2001:14:6cf:fae7:bb79:bf78:7d64:c056 - Subject: CN=2001:14:6cf:fae7:bb79:bf78:7d64:c056 + IP Address:HIT-OF-SUBJECT - X509v3 extensions: + Example X509v3 extensions: X509v3 Issuer Alternative Name: IP Address:2001:14:6CF:FAE7:BB79:BF78:7D64:C056 X509v3 Subject Alternative Name: - IP Address:2001:14:6CF:FAE7:BB79:BF78:7D64:C056 + IP Address:2001:1C:5A14:26DE:A07C:385B:DE35:60E3 Appendix B shows a full example X.509.v3 certificate with HIP content. As another example, consider a managed PKI environment in which the peers have certificates that are anchored in (potentially different) managed trust chains. In this scenario, the certificates issued to HIP hosts are signed by intermediate Certificate Authorities (CAs) up to a root CA. In this example, the managed PKI environment is neither HIP aware, nor can it be configured to compute HITs and include them in the certificates. - In this scenario, it is recommended that the HIP peers have and use + In this scenario, it is RECOMMENDED that the HIP peers have and use some mechanism of defining trusted root CAs for the purpose of establishing HIP communications. Furthermore it is recommended that the HIP peers have and use some mechanism of checking peer certificate validity for revocation, signature, minimum cryptographic strength, etc., up to the trusted root CA. When HIP communications are established, the HIP hosts not only need to send their identity certificates (or pointers to their certificates), but also the chain of intermediate CAs (or pointers to the CAs) up to the root CA, or to a CA that is trusted by the remote @@ -266,43 +269,43 @@ 5. Revocation of Certificates Revocation of X.509.v3 certificates is handled as defined in Section 5 in [RFC2459]. Revocation of SPKI certificates is handled as defined in Section 5 in [RFC2693]. 6. Error signaling If the Initiator does not send the certificate that the Responder - requires the Responder may take actions (e.g. blocking the - connection). The Responder MAY signal this to the Initiator by - sending a HIP NOTIFY message with NOTIFICATION parameter error type + requires the Responder may take actions (e.g. reject the connection). + The Responder MAY signal this to the Initiator by sending a HIP + NOTIFY message with NOTIFICATION parameter error type CREDENTIALS_NEEDED. If the verification of a certificate fails, a verifier MAY signal this to the provider of the certificate by sending a HIP NOTIFY message with NOTIFICATION parameter error type INVALID_CERTIFICATE. NOTIFICATION PARAMETER - ERROR TYPES Value ------------------------------------ ----- CREDENTIALS_REQUIRED 48 The Responder is unwilling to set up an association as the Initiator did not send the needed credentials. INVALID_CERTIFICATE 50 Sent in response to a failed verification of a certificate. - Notification Data contains 4 octets, in order Cert group, - Cert count, Cert ID, and Cert type of the certificate - parameter that caused the failure. + Notification Data MAY contain n groups of 2 octets (n calculated + from the NOTIFICATION parameter length), in order Cert group and + Cert ID of the certificate parameter that caused the failure. 7. IANA Considerations This document defines the CERT parameter for the Host Identity Protocol [RFC5201]. This parameter is defined in Section 2 with type 768. The parameter type number is also defined in [RFC5201]. The CERT parameter has 8-bit unsigned integer field for different certificate types, for which IANA is to create and maintain a new sub-registry entitled "HIP certificate types" under the "Host @@ -313,21 +316,21 @@ types" sub-registry under "Host Identity Protocol (HIP) Parameters". 8. Security Considerations Certificate grouping allows the certificates to be sent in multiple consecutive packets. This might allow similar attacks as IP-layer fragmentation allows, for example sending of fragments in wrong order and skipping some fragments to delay or stall packet processing by the victim in order to use resources (e.g. CPU or memory). - It is not recommended to use grouping or hash and URL encodings when + It is NOT RECOMMENDED to use grouping or hash and URL encodings when HIP aware middleboxes are anticipated to be present on the communication path between peers because fetching remote certificates require the middlebox to buffer the packets and to request remote data. This makes these devices prone to denial of service (DoS) attacks. Moreover, middleboxes and responders that request remote certificates can be used as deflectors for distributed denial of service attacks. 9. Acknowledgements @@ -360,20 +363,23 @@ X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile", RFC 3280, April 2002. [RFC4306] Kaufman, C., "Internet Key Exchange (IKEv2) Protocol", RFC 4306, December 2005. [RFC5201] Moskowitz, R., Nikander, P., Jokela, P., and T. Henderson, "Host Identity Protocol", RFC 5201, April 2008. + [RFC5952] Kawamura, S. and M. Kawashima, "A Recommendation for IPv6 + Address Text Representation", RFC 5952, August 2010. + 10.2. Informative References [X.690] ITU-T, "Recommendation X.690 Information Technology - ASN.1 encoding rules: Specification of Basic Encoding Rules (BER), Canonical Encoding Rules (CER) and Distinguished Encoding Rules (DER)", July 2002, . Appendix A. SPKI certificate example @@ -492,30 +498,43 @@ o Changed IANA considerations o Revised the type numbers o RFC 2119 keywords o Updated the IANA considerations section o Rewrote the abstract + Changes from version 04 to 05: + + o Clarified the examples in Section 3. + + o Clarifications to Section Section 3. + + o Modified the explanation of INVALID_CERTIFICATE to allow multiple + certs. + + o Added reference to the IPv6 colon delimited presentation format. + + o Small editorial changes. + Authors' Addresses Tobias Heer Distributed Systems Group, RWTH Aachen University Ahornstrasse 55 Aachen Germany Phone: +49 241 80 214 36 Email: heer@cs.rwth-aachen.de URI: http://ds.cs.rwth-aachen.de/members/heer Samu Varjonen Helsinki Institute for Information Technology - Metsaenneidonkuja 4 + Gustaf Haellstroemin katu 2b Helsinki Finland Email: samu.varjonen@hiit.fi URI: http://www.hiit.fi