Host Identity Protocol T. Heer
Internet-Draft Albstadt-Sigmaringen University
Obsoletes: 6253 (if approved) S. Varjonen
Updates: 7401 (if approved) University of Helsinki
Intended status: Standards Track April 22, 2016
Expires: October 24, 2016
Host Identity Protocol Certificates
draft-ietf-hip-rfc6253-bis-08
Abstract
The Certificate (CERT) parameter is a container for digital
certificates. It is used for carrying these certificates in Host
Identity Protocol (HIP) control packets. This document specifies the
certificate parameter and the error signaling in case of a failed
verification. Additionally, this document specifies the
representations of Host Identity Tags in X.509 version 3 (v3).
The concrete use cases of certificates, including how certificates
are obtained, requested, and which actions are taken upon successful
or failed verification, are specific to the scenario in which the
certificates are used. Hence, the definition of these scenario-
specific aspects is left to the documents that use the CERT
parameter.
This document updates RFC7401 and obsoletes RFC6253.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
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."
This Internet-Draft will expire on October 24, 2016.
Copyright Notice
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Copyright (c) 2016 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
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
1. Introduction
Digital certificates bind pieces 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) [RFC7401] 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 and issue certificates 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 [RFC7401], and thus, updates [RFC7401].
1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "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 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. Hence, the use of
the CERT parameter will be defined in the documents that use the CERT
parameter.
The CERT parameter is covered and protected, when present, by the HIP
SIGNATURE field and is a non-critical parameter.
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The CERT parameter can be used in all HIP packets. However, using it
in the first Initiator (I1) packet is NOT RECOMMENDED because it can
increase the processing times of I1s, which can be problematic when
processing storms of I1s. Each HIP control packet MAY contain
multiple CERT parameters each carrying one certificate. These
parameters MAY be related or unrelated. Related certificates are
managed in CERT groups. A CERT group specifies a group of related
CERT parameters that SHOULD be interpreted in a certain order (e.g.,
for expressing certificate chains). Ungrouped certificates exhibit a
unique CERT group field and set the CERT count to 1. CERT parameters
with the same group number in the CERT group field indicate a logical
grouping. The CERT count field indicates the number of CERT
parameters in the group.
CERT parameters that belong to the same CERT group MAY be contained
in multiple sequential HIP control packets. This is indicated by a
higher CERT count than the amount of CERT parameters with matching
CERT group fields in a HIP control packet. The CERT parameters MUST
be placed in ascending order, within a HIP control packet, according
to their CERT group field. CERT groups MAY only span multiple
packets if the CERT group does not fit the packet. A HIP packet MUST
NOT contain more than one incomplete CERT group that continues in the
next HIP control packet.
The CERT ID acts as a sequence number to identify the certificates in
a CERT group. The numbers in the CERT ID field MUST start from 1 up
to CERT count.
The CERT Group and CERT ID namespaces are managed locally by each
host that sends CERT parameters in HIP control packets.
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| CERT group | CERT count | CERT ID | CERT type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Certificate /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ | Padding (variable length) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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.
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CERT ID The sequence number for this certificate
CERT Type Indicates the type of the certificate
Padding Any Padding, if necessary, to make the TLV a multiple
of 8 bytes. Any added padding bytes MUST be zeroed by
the sender, and their values SHOULD NOT be checked by
the receiver.
The certificates MUST use the algorithms defined in [RFC7401] as the
signature and hash algorithms.
The following certificate types are defined:
+--------------------------------+-------------+
| CERT format | Type number |
+--------------------------------+-------------+
| Reserved | 0 |
| X.509 v3 | 1 |
| Obsoleted | 2 |
| Hash and URL of X.509 v3 | 3 |
| Obsoleted | 4 |
| LDAP URL of X.509 v3 | 5 |
| Obsoleted | 6 |
| Distinguished Name of X.509 v3 | 7 |
| Obsoleted | 8 |
+--------------------------------+-------------+
The next sections outline the use of Host Identity Tags (HITs) in
X.509 v3. X.509 v3 certificates and the handling procedures are
defined in [RFC5280]. The wire format for X.509 v3 is the
Distinguished Encoding Rules format as defined in [X.690].
Hash and Uniform Resource Locator (URL) encoding (3) is used as
defined in Section 3.6 of [RFC7296]. Using hash and URL encodings
results in smaller HIP control packets than by including the
certificate(s), but requires the receiver to resolve the URL or check
a local cache against the hash.
Lightweight Directory Access Protocol (LDAP) URL encoding (5) is used
as defined in [RFC4516]. 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) encoding (7) is represented by the string
representation of the certificate's subject DN as defined in
[RFC4514]. 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.
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3. X.509 v3 Certificate Object and Host Identities
If needed, HITs can represent an issuer, a subject, or both in X.509
v3. HITs are represented as IPv6 addresses as defined in [RFC7343].
When the Host Identifier (HI) is used to sign the certificate, the
respective HIT SHOULD be placed into the Issuer Alternative Name
(IAN) extension using the GeneralName form iPAddress as defined in
[RFC5280]. When the certificate is issued for a HIP host, identified
by a HIT and HI, the respective HIT SHOULD be placed into the Subject
Alternative Name (SAN) extension using the GeneralName form
iPAddress, and the full HI is presented as the subject's public key
info as defined in [RFC5280].
The following examples illustrate how HITs are presented as issuer
and subject in the X.509 v3 extension alternative names.
Format of X509v3 extensions:
X509v3 Issuer Alternative Name:
IP Address:hit-of-issuer
X509v3 Subject Alternative Name:
IP Address:hit-of-subject
Example X509v3 extensions:
X509v3 Issuer Alternative Name:
IP Address:2001:24:6cf:fae7:bb79:bf78:7d64:c056
X509v3 Subject Alternative Name:
IP Address:2001:2c:5a14:26de:a07c:385b:de35:60e3
Appendix A shows a full example X.509 v3 certificate with HIP
content.
As another example, consider a managed Public Key Infrastructure
(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 Certification 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.
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
peer. This chain of certificates SHOULD be sent in a CERT group as
specified in Section 2. The HIP peers validate each other's
certificates and compute peer HITs based on the certificate public
keys.
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4. Revocation of Certificates
Revocation of X.509 v3 certificates is handled as defined in
Section 5 of [RFC5280] with two exceptions. First, any HIP
certificate serial number that appears on the CRL is treated as
invalid regardless of the reason code. Second, the certificateHold
is not supported.
5. Error Signaling
If the Initiator does not send all the certificates that the
Responder 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_REQUIRED.
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 MAY contain CERT group and CERT ID octet
(in this order) of the CERT parameter that caused the
failure.
6. IANA Considerations
The following changes to the "HIP Certificate Types" registry should
be made.
The references should be updated from [RFC6253] to this document.
This document obsoleted the type numbers "2", "4", "6", "8" for
the SPKI certificates.
7. Security Considerations
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Certificate grouping allows the certificates to be sent in multiple
consecutive packets. This might allow similar attacks, as IP-layer
fragmentation allows, for example, the sending of fragments in the
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). Hence, hosts SHOULD implement mechanisms to discard
certificate groups with outstanding certificates if state space is
scarce.
Although, CERT parameter is allowed in the first Initiator (I1)
packet it is NOT RECOMMENDED because it can increase the processing
times of I1s, which can be problematic when processing storms of I1s.
Furthermore, Initiator has to take into consideration that the
Responder can drop the CERT parameter in I1 without processing the
parameter.
Checking of the URL and LDAP entries might allow denial-of-service
(DoS) attacks, where the target host may be subjected to bogus work.
Security considerations for X.509 v3 are discussed in [RFC5280].
8. Differences from RFC 6253
This section summarizes the technical changes made from [RFC6253].
This section is informational, intended to help implementors of the
previous protocol version. If any text in this section contradicts
text in other portions of this specification, the text found outside
of this section should be considered normative.
The following changes have been made.
o Support for Simple Public Key Infrastructure (SPKI) certificates
has been removed.
9. Acknowledgements
The authors would like to thank A. Keranen, D. Mattes, M. Komu and T.
Henderson for the fruitful conversations on the subject. D. Mattes
most notably contributed the non-HIP aware use case in Section 3.
10. References
10.1. 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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[RFC4514] Zeilenga, K., "Lightweight Directory Access Protocol
(LDAP): String Representation of Distinguished Names", RFC
4514, June 2006.
[RFC4516] Smith, M. and T. Howes, "Lightweight Directory Access
Protocol (LDAP): Uniform Resource Locator", RFC 4516, June
2006.
[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
Housley, R., and W. Polk, "Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 5280, May 2008.
[RFC7296] Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T.
Kivinen, "Internet Key Exchange Protocol Version 2
(IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October
2014, <http://www.rfc-editor.org/info/rfc7296>.
[RFC7343] Laganier, J. and F. Dupont, "An IPv6 Prefix for Overlay
Routable Cryptographic Hash Identifiers Version 2
(ORCHIDv2)", RFC 7343, DOI 10.17487/RFC7343, September
2014, <http://www.rfc-editor.org/info/rfc7343>.
[RFC7401] Moskowitz, R., Heer, T., Jokela, P., and T. Henderson,
"Host Identity Protocol Version 2 (HIPv2)", RFC 7401,
April 2015.
[X.690] ITU-T, , "Recommendation X.690 (2002) | ISO/IEC
8825-1:2002, Information Technology - ASN.1 encoding
rules: Specification of Basic Encoding Rules (BER),
Canonical Encoding Rules (CER) and Distinguished Encoding
Rules (DER)", July 2002.
10.2. Informative References
[RFC6253] Heer, T. and S. Varjonen, "Host Identity Protocol
Certificates", RFC 6253, DOI 10.17487/RFC6253, May 2011,
<http://www.rfc-editor.org/info/rfc6253>.
Appendix A. X.509 v3 certificate example
This section shows a X.509 v3 certificate with encoded HITs.
Certificate:
Data:
Version: 3 (0x2)
Serial Number: 12705268244493839545 (0xb0522e27291b2cb9)
Signature Algorithm: sha256WithRSAEncryption
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Issuer: DC=Example, DC=com, CN=Example issuing host
Validity
Not Before: Feb 25 11:28:29 2016 GMT
Not After : Feb 24 11:28:29 2017 GMT
Subject: DC=Example, DC=com, CN=Example issuing host
Subject Public Key Info:
Public Key Algorithm: rsaEncryption
Public-Key: (2048 bit)
Modulus:
00:c9:b0:85:94:af:1f:3a:77:39:c9:d5:81:a5:ee:
d2:b5:6b:72:91:5d:22:2c:1e:59:e5:06:29:bd:a2:
19:f6:ac:ca:eb:f7:88:d8:54:55:41:01:58:d8:87:
64:d8:c8:cf:6e:c2:38:81:22:1a:ae:e9:a6:80:22:
03:ee:f3:1b:7e:68:11:e3:f4:7b:98:33:28:bf:40:
ec:4f:19:e8:10:8a:8b:07:60:f7:9f:e4:82:f8:a7:
58:04:3d:42:07:c8:34:ca:99:6d:11:eb:73:c1:d9:
96:93:55:e5:c7:ed:80:4f:8a:f2:1a:6f:83:c8:15:
a4:8f:b8:6a:fe:f3:4f:49:1a:5c:1f:89:bb:30:e6:
98:bc:ce:a3:a2:37:85:b1:79:1c:26:e6:44:0c:b9:
3e:d8:37:81:46:f4:02:25:46:a2:ea:da:25:5c:46:
a2:a3:c5:58:80:53:1f:c5:e5:11:a0:da:d8:f2:ad:
d6:98:d4:ce:55:35:cc:0b:d3:5b:09:48:ef:57:65:
80:cb:65:79:fd:cb:4d:5b:b3:8d:1a:ff:2a:58:3e:
96:65:10:3e:04:81:78:2b:d5:ca:89:78:ea:28:5c:
bc:02:4a:54:cd:aa:a9:99:8d:d6:39:e9:5e:a9:73:
1a:5d:93:55:39:9b:72:1a:c2:a0:1f:e3:4c:b0:41:
98:97
Exponent: 65537 (0x10001)
X509v3 extensions:
X509v3 Subject Alternative Name:
IP Address:2001:27:DCFC:CB8:F885:D53F:4E63:48B7
X509v3 Issuer Alternative Name:
IP Address:2001:2D:F878:64C1:67E3:9716:88BD:68E4
Signature Algorithm: sha256WithRSAEncryption
6d:e6:a9:a6:30:c4:ab:3e:86:39:1e:de:76:4d:4e:a4:2d:63:
4d:bb:41:bf:d3:0c:66:13:8b:4d:b2:50:59:36:fc:ae:42:9e:
c8:a0:41:1a:1c:94:56:05:28:82:34:4e:63:75:87:31:25:67:
36:a6:1a:0f:b8:f7:db:03:e7:dd:a6:9a:26:c4:68:e2:cf:59:
54:e6:ee:cc:a7:ce:fb:56:bf:31:60:f4:cb:e7:f0:0e:50:f8:
b7:c5:3c:1a:de:74:d0:aa:83:e5:15:25:b1:bf:be:a4:7f:af:
0a:de:08:09:0e:13:1d:2a:3b:1a:99:d9:af:10:fc:08:92:5f:
d8:d0:10:d6:b9:0c:86:da:85:3b:44:b5:97:90:10:02:4f:5a:
1f:ae:07:30:6b:f5:e6:12:93:72:e2:10:c9:8e:2c:00:8b:d6:
f0:05:c3:ff:91:24:69:6d:5b:5a:0c:40:28:01:f2:5b:45:b8:
9b:ae:9e:73:e9:dd:83:e0:85:d7:ad:6c:b1:81:ac:a0:30:37:
9d:60:bd:92:3b:d2:a1:21:87:8b:c4:d9:5a:5c:21:56:3e:02:
7e:f3:6f:a5:de:40:75:80:f5:41:68:5c:b2:61:fb:1d:9a:a5:
97:a8:d4:a9:82:45:86:79:3c:63:76:3d:fd:86:a0:f8:14:84:
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55:c1:8c:fa
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
Appendix B. Change log
Contents of draft-ietf-hip-rfc6253-bis-00:
o RFC6253 was submitted as draft-RFC.
Changes from version 01 to 02:
o Updated the references.
Changes from version 02 to 03:
o Fixed the nits raised by the working group.
Changes from version 03 to 04:
o Added "obsoletes RFC 6253".
Changes from version 04 to 05:
o Updates to contact details.
o Correct updates and obsoletes headers.
o Removed the pre5378 disclaimer.
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o Updated references.
o Removed the SPKI references from the document.
Changes from version 05 to 06:
o Addressed the Int-Dir review comments from Korhonen.
Changes from version 06 to 07:
o Addressed the GenArt, OPSdir, SecDir, and IANA comments.
Changes from version 07 to 08:
o Addresses one editorial nit for CERT group numbers.
Authors' Addresses
Tobias Heer
Albstadt-Sigmaringen University
Poststr. 6
72458 Albstadt
Germany
Email: heer@hs-albsig.de
Samu Varjonen
University of Helsinki
Gustaf Haellstroemin katu 2b
00560 Helsinki
Finland
Email: samu.varjonen@helsinki.fi
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