Internet DRAFT - draft-chen-sidrops-sispi
draft-chen-sidrops-sispi
SIDR Operations L. Chen
Internet-Draft L. Liu
Intended status: Standards Track Zhongguancun Laboratory
Expires: 25 August 2024 D. Li
L. Qin
Tsinghua University
22 February 2024
A Profile of Signed SAVNET-Peering Information (SiSPI) Object for
Deploying Inter-domain SAVNET
draft-chen-sidrops-sispi-00
Abstract
This document defines a "Signed SAVNET-Peering Information" (SiSPI)
object, a Cryptographic Message Syntax (CMS) protected content type
included in the Resource Public Key Infrastructure (RPKI). A SiSPI
object is a digitally signed object which carries the list of
Autonomous Systems (ASes) deploying inter-domain SAVNET. When
validated, the eContent of a SiSPI object confirms that the holder of
the listed ASN produces the object and the AS has deployed inter-
domain SAV and is ready to establish neighbor relationship for
preventing source address spoofing.
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
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This Internet-Draft will expire on 25 August 2024.
Copyright Notice
Copyright (c) 2024 IETF Trust and the persons identified as the
document authors. All rights reserved.
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This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
1.2. Requirements Language . . . . . . . . . . . . . . . . . . 4
2. The SiSPI Content Type . . . . . . . . . . . . . . . . . . . 4
3. The SiSPI eContent . . . . . . . . . . . . . . . . . . . . . 4
3.1. version . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.2. asID . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.3. IPAddress . . . . . . . . . . . . . . . . . . . . . . . . 5
4. SiSPI Validation . . . . . . . . . . . . . . . . . . . . . . 5
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
5.1. RPKI Signed Object Registry . . . . . . . . . . . . . . . 6
5.2. RPKI Repository Name Scheme Registry . . . . . . . . . . 7
5.3. Media Type Registry . . . . . . . . . . . . . . . . . . . 7
6. Using SiSPI . . . . . . . . . . . . . . . . . . . . . . . . . 7
7. Security Considerations . . . . . . . . . . . . . . . . . . . 9
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
8.1. Normative References . . . . . . . . . . . . . . . . . . 9
8.2. Informative References . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11
1. Introduction
Attacks based on source IP address spoofing, such as reflective DDoS
and flooding attacks, continue to present significant challenges to
Internet security. Mitigating these attacks in inter-domain networks
requires effective source address validation (SAV). While BCP84
[RFC3704] [RFC8704] offers some SAV solutions, such as ACL-based
ingress filtering and uRPF-based mechanisms, existing inter-domain
SAV mechanisms have limitations in terms of validation accuracy and
operational overhead in different scenarios [inter-domain-ps].
Inter-domain SAVNET [savnet] proposes to exchange SAV-specific
information among ASes to solve the problems of existing inter-domain
SAV mechanisms. Two SAV-specific information exchanging protocols
(or SAVNET protocols for short) are shown to achieve higher
validation accuracy and lower operational overhead in large-scale
emulations [emu-9-savs]. However, operators face significant
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difficulties in deploying SAVNET protocols. To benefit Internet
routing, supporting incremental deployment is an essential
requirement of SAVNET protocols [inter-domain-ps]. As illustrated in
the Section 8 of [savnet], during the partial or incremental
deployment of SAVNET protocols, protocol-speaking agents (or SAVNET
agents) within the SAVNET-adopting ASes need to find and establish
connections with other SAVNET agents. Currently, there is no
mechanism to achieve this automatically, and operators of SAVNET-
adopting ASes must configure peering SAVNET relationship by hand,
which is slow and error-prone.
The neighbor discovery and connection setup process of SAV protocols
can be done in an automatic and correct manner, with the introduction
of a public registry that contains all ASes which both deploy SAVNET
and are willing to setup SAVNET peering relationships. A newly
adopting AS can use this registry as a reference, and pick
appropriate ASes to setup SAVNET peering relationship.
The Resource Public Key Infrastructure (RPKI) is the most suitable to
host this public registry, because the primary purpose of RPKI is to
improve routing security [RFC6480], and defending against address
spoofing is a main aspect of routing security. To this end, a
mechanism is needed to facilitate holders of Automous System (AS)
identifiers to declare their deployment of SAVNET [savnet]. The
digitally Signed SAVNET-Peering Information (SiSPI) object described
in this document serves the function.
A SiSPI object is a cryptographically verifiable attestation signed
by the holder of an AS identifier. It contains the identification
information of one AS, which means the listed AS has deployed SAVNET
and can perform SAV on its data plane.
The SiSPI object makes use of the template for RPKI digitally signed
objects [RFC6488], which defines a Crytopgraphic Message Syntax (CMS)
[RFC5652] wrapper for the SiSPI content as well as a generic
validation procedure for RPKI signed objects. In accordance with
Section 4 of [RFC6488], this document defines:
1. The object identifier (OID) that identifies the SiSPI object.
This OID appears in the eContentType field of the
enCapContentInfo object as well as the content-type signed
attribute within the signerInfo structure.
2. The ASN.1 syntax for the SiSPI eContent, which is the payload
that specifies the AS deploying SAVNET. The SiSPI eContent is
encoded using the ASN.1 Distinguished Encoding Rules (DER)
[X.690].
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3. The steps required to validate a SiSPI beyond the validation
steps specified in [RFC6488].
1.1. Terminology
This document makes use of the terms and concepts described in
"Internet X.509 Public Key Infrastructure Certificate and Certificate
Revocation List (CRL) Profile" [RFC5280], "X.509 Extensions for IP
Address and AS Identifiers" [RFC3779], "Signed Object Template for
the Resource Public Key Infrastructure (RPKI)" [RFC6488], and "A
Profile for X.509 PKIX Resource Certificates" [RFC6487]. The readers
should be familiar with the terms and concepts.
1.2. 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
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
2. The SiSPI Content Type
The content-type for a SiSPI object is defined as SAVNETAuthz, which
has the numerical value of 1.2.840.113549.1.9.16.1.52. This OID MUST
appear both within the eContentType in the encapContentInfo structure
as well as the content-type signed attribute within the signerInfo
structure (see [RFC6488]).
3. The SiSPI eContent
The content of a SiSPI object identifies a single AS that has
deployed SAVNET [savnet] for inter-domain SAV. The eContent of a
SiSPI object is an instance of SAVNETAttestation, formally defined by
the following ASN.1 [X.680] module:
SAVNETAttestation ::= SEQUENCE {
version [0] INTEGER DEFAULT 0,
asID ASID,
address IPAddress }
ASID ::= INTEGER (0..4294967295)
IPAddress ::= BIT STRING
Note that this content appears as the eContent within the
encapContentInfo as specified in [RFC6488].
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3.1. version
The version number of the SAVNETAttestation that compiles with this
specification MUST be 2 and MUST be explicitly encoded.
3.2. asID
The asID field contains the AS number that has deployed SAVNET and
can perform SAV on the data plane.
3.3. IPAddress
The IPAddress field stores the router's IP address within the AS
whose ID is asID, which is utilized for establishing SAVNET
connections.
4. SiSPI Validation
Before, a relying party can use a SiSPI object to validate a routing
announcement, the relying party MUST first validate the SiSPI object.
To validate a SiSPI object, the relying party MUST perform all the
validation checks specified in [RFC6488] as well as the following
additional specific validation steps of the Signed AS List.
* The AS Identifier Delegation Extension [RFC3779] MUST be present
in the end-entity (EE) certificate (contained within the SiSPI
object), and the asID in the SiSPI object eContent MUST be
contained within the set of AS numbers specified by the EE
certificate's AS Identifier Delegation Extension.
* The EE certificate's AS Identifier Delegation Extension MUST NOT
contain any ''inherit'' elements.
* The IP Address Delegation Extension [RFC3779] MUST be absent.
The pseudocode for SiSPI validation is as follows:
function ValidateSiSPI(sispiObject, eeCertificate):
// Step 1: Validate the SiSPI object using the generic RPKI
// validation procedure.
// This includes checking the CMS wrapper, signature, and
// certification path.
if not IsValidRPKISignedObject(sispiObject):
return False, "Invalid RPKI Signed Object"
// Step 2: Check the content-type of the SiSPI object.
if not sispiObject.eContentType == SAVNETAuthzOID:
return False, "Invalid content-type"
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// Step 3: Parse the eContent of the SiSPI object as
// SAVNETAttestation.
sispiContent = ParseSAVNETAttestation(sispiObject.eContent)
if sispiContent is None:
return False, "Unable to parse SAVNETAttestation"
// Step 4: Ensure the version number is explicitly set to 2.
if not (sispiContent.version exists and sispiContent.version==2):
return False, "Invalid version"
// Step 5: Validate the AS Identifier Delegation Extension in
// the EE certificate.
if not ValidateASIdExt(eeCertificate, sispiContent.asID):
return False, "AS Identifier Extension validation failed"
// Step 6: Ensure the EE certificate's AS Identifier Delegation
// Extension does not contain 'inherit'.
if "inherit" in eeCertificate.asIdentifiers:
return False,
"AS Identifier Delegation Extension contains 'inherit'"
// Step 7: Ensure the IP Address Delegation Extension is absent.
if HasIPAddressDelegationExtension(eeCertificate):
return False, "IP Address Delegation Extension is present"
// Step 8: Determine if all validation checks are successful.
return True, "SiSPI object is valid"
function ValidateASIdentifierExtension(eeCertificate, asID):
// Check if the asID is within the set of AS numbers
// specified by the AS Identifier Delegation Extension.
return asID in eeCertificate.asIdentifiers
function HasIPAddressDelegationExtension(eeCertificate):
// Check for the presence of the IP Address Delegation
// Extension.
return "ipAddresses" in eeCertificate.extensions
5. IANA Considerations
5.1. RPKI Signed Object Registry
Please add an item for the SiSPI object file extension to the RPKI
Signed Object registry (https://www.iana.org/assignments/rpki/
rpki.xhtml#signed-objects) as follows:
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Name | OID
---------------------------------------------
Signed SAVNET-Peering Information | 1.2.840.113549.1.9.16.1.52
5.2. RPKI Repository Name Scheme Registry
Please add an item for the SiSPI object file extension to the "RPKI
Repository Name Scheme" registry created by [RFC6481] as follows:
Filename
Extension | RPKI Object | Reference
------------------------------------------------------------------------
.sav | Signed SAVNET-Peering Information | draft-chen-sidrops-sispi
5.3. Media Type Registry
The IANA is requested to register the media type application/rpki-
sispi in the "Media Type" registry as follows:
Type name: application
Subtype name: rpki-sispi
Required parameters: N/A
Optional parameters: N/A
Encoding considerations: binary
Security considerations: Carries Signed SAVNET-Peering Information.
This media type contains no active content. See
Section 4 of draft-chen-sidrops-sispi for further information.
Interoperability considerations: None
Published specification: draft-chen-sidrops-sispi
Applications that use this media type: RPKI operators
Additional information:
Content: This media type is a signed object, as defined
in {{RFC6488}}, which contains a payload of an AS identifer
as defined in draft-chen-sidrops-sispi.
Magic number(s): None
File extension(s): .sav
Macintosh file type code(s):
Person & email address to contact for further information:
Li Chen <lichen@zgclab.edu.cn>
Intended usage: COMMON
Restrictions on usage: None
Change controller: IETF
6. Using SiSPI
A router can use the AS_Path from BGP announcements, ASPA objects,
and SiSPI to find the closest ASes to set up SAVNET peering, as
described below:
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1. BGP AS_Paths Analysis:
* Collect AS paths from BGP announcements.
* Determine the frequency or preference of certain AS paths
based on routing policies, which may involve path attributes
like AS path length, origin type, local preference, and MED
(Multi-Exit Discriminator).
2. ASPA Verification:
* Use ASPA objects to verify the legitimacy of provider-customer
AS relationships.
* Ensure that the AS paths conform to the provider-customer
relationships indicated by the ASPAs, thereby validating the
correctness of the routing information.
3. Closest AS Determination:
* Identify the ASes that frequently appear on the preferred
paths to various destinations, implying they are topologically
'close' or significant transit providers.
* Among these ASes, prioritize those that have a direct
provider-customer relationship with the local AS (as indicated
by ASPA objects), since they are potentially the closest
peers.
4. SiSPI Objects Utilization:
* Retrieve SiSPI objects from the RPKI repository to determine
which ASes have deployed SAVNET.
* Filter the previously identified closest ASes by checking
whether they have a valid SiSPI object, which would indicate
their readiness to establish SAVNET peering.
5. Peering Candidates Selection:
* From the set of closest ASes with valid SiSPI objects, select
candidates for SAVNET peering.
* The selection criteria may include additional factors such as
existing peering policies, traffic volumes, and peering
agreements.
6. Peering Establishment:
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* Initiate peering negotiations with the selected candidate
ASes.
* Upon successful negotiation, establish SAVNET peering
relationships and configure the necessary SAVNET protocols.
7. Security Considerations
The security considerations of [RFC6481], [RFC6485], and [RFC6488]
also apply to the SiSPI object.
8. References
8.1. Normative References
[RFC3704] Baker, F. and P. Savola, "Ingress Filtering for Multihomed
Networks", BCP 84, RFC 3704, DOI 10.17487/RFC3704, March
2004, <https://www.rfc-editor.org/rfc/rfc3704>.
[RFC8704] Sriram, K., Montgomery, D., and J. Haas, "Enhanced
Feasible-Path Unicast Reverse Path Forwarding", BCP 84,
RFC 8704, DOI 10.17487/RFC8704, February 2020,
<https://www.rfc-editor.org/rfc/rfc8704>.
[RFC6480] Lepinski, M. and S. Kent, "An Infrastructure to Support
Secure Internet Routing", RFC 6480, DOI 10.17487/RFC6480,
February 2012, <https://www.rfc-editor.org/rfc/rfc6480>.
[RFC6488] Lepinski, M., Chi, A., and S. Kent, "Signed Object
Template for the Resource Public Key Infrastructure
(RPKI)", RFC 6488, DOI 10.17487/RFC6488, February 2012,
<https://www.rfc-editor.org/rfc/rfc6488>.
[RFC5652] Housley, R., "Cryptographic Message Syntax (CMS)", STD 70,
RFC 5652, DOI 10.17487/RFC5652, September 2009,
<https://www.rfc-editor.org/rfc/rfc5652>.
[RFC3779] Lynn, C., Kent, S., and K. Seo, "X.509 Extensions for IP
Addresses and AS Identifiers", RFC 3779,
DOI 10.17487/RFC3779, June 2004,
<https://www.rfc-editor.org/rfc/rfc3779>.
[RFC6481] Huston, G., Loomans, R., and G. Michaelson, "A Profile for
Resource Certificate Repository Structure", RFC 6481,
DOI 10.17487/RFC6481, February 2012,
<https://www.rfc-editor.org/rfc/rfc6481>.
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[RFC6485] Huston, G., "The Profile for Algorithms and Key Sizes for
Use in the Resource Public Key Infrastructure (RPKI)",
RFC 6485, DOI 10.17487/RFC6485, February 2012,
<https://www.rfc-editor.org/rfc/rfc6485>.
[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, DOI 10.17487/RFC5280, May 2008,
<https://www.rfc-editor.org/rfc/rfc5280>.
[RFC6487] Huston, G., Michaelson, G., and R. Loomans, "A Profile for
X.509 PKIX Resource Certificates", RFC 6487,
DOI 10.17487/RFC6487, February 2012,
<https://www.rfc-editor.org/rfc/rfc6487>.
[X.690] "Information Technology - ASN.1 encoding rules;
Specification of Basic Encoding Rules (BER), Canonical
Encoding Rules (CER) and Distinguished Encoding Rules
(DER)", 2021.
[X.680] "Information technology - Abstract Syntax Notation One
(ASN.1); Specification of basic notation", 2021.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/rfc/rfc2119>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/rfc/rfc8174>.
8.2. Informative References
[inter-domain-ps]
"Source Address Validation in Inter-domain Networks Gap
Analysis, Problem Statement, and Requirements", 2023,
<https://datatracker.ietf.org/doc/draft-ietf-savnet-inter-
domain-problem-statement/>.
[savnet] "Inter-domain Source Address Validation (SAVNET)
Architecture", 2023, <https://datatracker.ietf.org/doc/
draft-wu-savnet-inter-domain-architecture/>.
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[emu-9-savs]
"Emulations of 9 SAV Mechanisms with SAV Open Playground",
2023, <https://datatracker.ietf.org/meeting/118/materials/
slides-118-savnet-emulations-of-nine-sav-mechanisms-with-
sav-open-playground-00>.
Authors' Addresses
Li Chen
Zhongguancun Laboratory
Beijing
China
Email: lichen@zgclab.edu.cn
Libin Liu
Zhongguancun Laboratory
Beijing
China
Email: liulb@zgclab.edu.cn
Dan Li
Tsinghua University
Beijing
China
Email: tolidan@tsinghua.edu.cn
Lancheng Qin
Tsinghua University
Beijing
China
Email: qlc19@mails.tsinghua.edu.cn
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