One document matched: draft-ietf-sidr-bogons-01.xml
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<?rfc toc="yes"?>
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<rfc category="std" docName="draft-ietf-sidr-bogons-01.txt" ipr="full3978">
<front>
<title abbrev="Bogon Attestations">A Profile for Bogon Origin Attestations
(BOAs)</title>
<author fullname="Geoff Huston" initials="G." surname="Huston">
<organization abbrev="APNIC">Asia Pacific Network Information
Centre</organization>
<address>
<email>gih@apnic.net</email>
<uri>http://www.apnic.net</uri>
</address>
</author>
<author fullname="George Michaelson" initials="G." surname="Michaelson">
<organization abbrev="APNIC">Asia Pacific Network Information
Centre</organization>
<address>
<email>ggm@apnic.net</email>
<uri>http://www.apnic.net</uri>
</address>
</author>
<author fullname="Terry Manderson" initials="T." surname="Manderson">
<organization></organization>
<address>
<email>terry@terrym.net</email>
</address>
</author>
<date year="2008" />
<area>Individual Submission</area>
<workgroup>Individual Submission</workgroup>
<abstract>
<t>This document defines a standard profile for Bogon Origin
Attestations (BOAs). A BOA is a digitally signed object that
provides a means of verifying that an IP address block holder
has not authorized any Autonomous System (AS) to originate
routes that are equivalent to any of the addresses listed in the
BOA. A BOA also provides a means of verifying that BGP speaker
is not using an AS without appropriate authority to use that
AS. The proposed application of BOAs is intended to fit within
the requirements for adding security measures to inter-domain
routing, including the ability to support incremental and
piecemeal deployment of such measures, and does not require any
changes to the specification of the Border Gateway Protocol.
</t>
</abstract>
</front>
<middle>
<section anchor="intro" title="Introduction">
<t>This document defines an application of the Resource Public
Key Infrastructure (RPKI) to validate the attestations of
Internet Registries that certain addresses are currently neither
allocated nor assigned to any party, and any appearance of such
addresses or AS's in a routing advertisement in the Border
Gateway Protocol (BGP) <xref target="RFC4271"></xref> should be
considered an invalid use of such addresses or AS's.</t>
<t>The RPKI is based on Resource Certificates. Resource
Certificates are X.509 certificates that conform to the PKIX
profile <xref target="RFC5280"></xref>, and to the extensions
for IP addresses and AS identifiers <xref
target="RFC3779"></xref>. A Resource Certificate describes an
action by an Issuer that binds a list of IP address blocks and
Autonomous System (AS) numbers to the Subject of a certificate,
identified by the unique association of the Subject's private
key with the public key contained in the Resource
Certificate. The RPKI is structured such that each current
Resource Certificate matches a current resource allocation or
assignment. This is described in <xref
target="ID.ietf-sidr-arch"></xref>.</t>
<t>BOAs can be regarded as a logical opposite of a Route Origin
Authorization (ROA) <xref target="ID.ietf-sidr-roa-format" />,
and allows a resource holder to explicitly list those IP
addresses and AS's that are denoted by the holder as not validly
appearing in any routing advertisement, and to make this
attestation in a manner that a relying party can validate under
the framework of the RPKI.</t>
<t>A BOA is a digitally signed object that makes use of
Cryptographic Message Syntax (CMS) <xref
target="RFC3852"></xref> as a standard encapsulation format. CMS
was chosen to take advantage of existing open source software
available for processing messages in this format.</t>
</section>
<section title="Basic Format">
<t>Using CMS syntax, a BOA is a type of signed-data object. The
general format of a CMS object is:</t>
<figure>
<artwork><![CDATA[
ContentInfo ::= SEQUENCE {
contentType ContentType,
content [0] EXPLICIT ANY DEFINED BY contentType }
ContentType ::= OBJECT IDENTIFIER
]]></artwork>
</figure>
<section title="Signed-Data Content Type">
<t>According to the CMS specification, The signed-data content type
shall have ASN.1 type SignedData:</t>
<figure>
<artwork><![CDATA[
SignedData ::= SEQUENCE {
version CMSVersion,
digestAlgorithms DigestAlgorithmIdentifiers,
encapContentInfo EncapsulatedContentInfo,
certificates [0] IMPLICIT CertificateSet OPTIONAL,
crls [1] IMPLICIT RevocationInfoChoices OPTIONAL,
signerInfos SignerInfos }
DigestAlgorithmIdentifiers ::= SET OF DigestAlgorithmIdentifier
SignerInfos ::= SET OF SignerInfo
]]></artwork>
</figure>
<section title="version">
<t>The version is the syntax version number. It MUST be 3,
corresponding to the signerInfo structure having version number
3.</t>
</section>
<section title="digestAlgorithms">
<t>The digestAlgorithms set MUST include only SHA-256, the
OID for which is 2.16.840.1.101.3.4.2.1. <xref
target="RFC4055" />. It MUST NOT contain any other
algorithms.</t>
</section>
<section title="encapContentInfo">
<t>encapContentInfo is the signed content, consisting of a
content type identifier and the content itself.</t>
<figure>
<artwork><![CDATA[
EncapsulatedContentInfo ::= SEQUENCE {
eContentType ContentType,
eContent [0] EXPLICIT OCTET STRING OPTIONAL }
ContentType ::= OBJECT IDENTIFIER
]]></artwork>
</figure>
<section title="eContentType">
<t>The ContentType for a BOA is defined as id-ct-rpkiBOA,
and has the numerical value of
1.2.840.113549.1.9.16.1.[TBD]. [This value needs to be
assigned via an OID registration.]</t>
<figure>
<artwork><![CDATA[
id-smime OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840)
rsadsi(113549) pkcs(1) pkcs9(9) 16 }
id-ct OBJECT IDENTIFIER ::= { id-smime 1 }
id-ct-rpkiBOA OBJECT IDENTIFIER ::= { id-ct [TBD] }
]]></artwork>
</figure>
</section>
<section title="eContent">
<t>The content of a BOA identifies a list of one or more
AS's and one or more IP address prefixes that are asserted
to be "bogons" and, accordingly, BOAs are intended to act
as a constraint on the routing system to signal that no
route object that that relates to these AS's or IP
addresses should be interpreted as representing a valid
routing attestation. A BOA is formally defined as:</t>
<figure>
<artwork><![CDATA[
id-ct-rpkiBOA ::= {
version [0] INTEGER DEFAULT 0,
asIDs SEQUENCE OF asIdsOrRange,
ipAddrBlocks SEQUENCE OF BOAIPAddressFamily }
ASIdOrRange ::= CHOICE {
id ASId,
range ASRange }
ASRange ::= SEQUENCE {
min ASId,
max ASId }
ASId ::= INTEGER
BOAIPAddressFamily ::= SEQUENCE {
addressFamily OCTET STRING (SIZE (2..3)),
addresses SEQUENCE OF IPAddress }
IPAddress ::= BIT STRING
]]></artwork>
</figure>
<section title="version">
<t>The version number of the BogonOriginAttestation MUST
be 0.</t>
</section>
<section title="asIDs">
<t>The asIDs field contains the AS numbers that are to
be regarded as Bogon AS's. The set of AS numbers may be
explicitly listed, or specified as a continuous range of
values. The field is to be formatted as per the
canonical format specified in <xref
target="RFC3779"></xref>.</t>
</section>
<section title="BOAIPAddressFamily">
<t>The BOAIPAddressFamily field encodes the set of IP
address prefixes that are to be regarded as Bogon IP
addresses that are to be constrained from appearing in
any routing advertisement. The intended semantics of an
address prefix in a BOA is that any route object that
has the same address prefix as that listed as a Bogon IP
address, or is a more specific prefix of a Bogon IP
address can be regarded as a Bogon route object.</t>
<t>The syntax of the addres prefixes listed in a BOA
uses a subset of the IP Address Delegation extension
defined in <xref target="RFC3779"></xref>. The
BOAIPAddressFamily cannot contain arbitrary address
ranges, but in all other respects uses the same
canonical format as the IP Address Delegation
Extension.</t>
<t>Within the BOAIPAddressFamily structure,
addressFamily contains the Address Family Identifier
(AFI) of an IP address family. This specification only
supports IPv4 and IPv6. Therefore, addressFamily MUST
be either 0001 or 0002. The addresses field represents
prefixes as a sequence of type IPAddress, as defined
in<xref target="RFC3779"></xref>.</t>
</section>
</section>
</section>
<section title="certificates">
<t>The certificates field MUST be included, and MUST contain
only the end entity (EE) certificate needed to validate this
BOA.</t>
</section>
<section title="crls">
<t>The crls field MUST be omitted.</t>
</section>
<section title="signerInfo">
<t>SignerInfo is defined under CMS as:</t>
<figure>
<artwork><![CDATA[
SignerInfo ::= SEQUENCE {
version CMSVersion,
sid SignerIdentifier,
digestAlgorithm DigestAlgorithmIdentifier,
signedAttrs [0] IMPLICIT SignedAttributes OPTIONAL,
signatureAlgorithm SignatureAlgorithmIdentifier,
signature SignatureValue,
unsignedAttrs [1] IMPLICIT UnsignedAttributes OPTIONAL }
]]></artwork>
</figure>
<section title="version">
<t>The version number MUST be 3, corresponding with the
choice of SubjectKeyIdentifier for the sid.</t>
</section>
<section title="sid">
<t>The sid is defined as:</t>
<figure>
<artwork><![CDATA[
SignerIdentifier ::= CHOICE {
issuerAndSerialNumber IssuerAndSerialNumber,
subjectKeyIdentifier [0] SubjectKeyIdentifier }
]]></artwork>
</figure>
<t>For a BOA, the sid MUST be a SubjectKeyIdentifier.</t>
</section>
<section title="digestAlgorithm">
<t>The digestAlgorithm MUST be SHA-256, the OID for which is
2.16.840.1.101.3.4.2.1. <xref target="RFC4055"></xref></t>
</section>
<section title="signedAttrs">
<t>Signed Attributes are defined as:</t>
<figure>
<artwork><![CDATA[
SignedAttributes ::= SET SIZE (1..MAX) OF Attribute
Attribute ::= SEQUENCE {
attrType OBJECT IDENTIFIER,
attrValues SET OF AttributeValue }
AttributeValue ::= ANY
]]></artwork>
</figure>
<t>The signedAttr element MUST be present and MUST include
the content- type and message-digest attributes. The
signer MAY also include the signing-time signed attribute,
the binary-signing-time signed attribute, or both signed
attributes. Other signed attributes that are deemed
appropriate MAY also be included. The intent is to allow
additional signed attributes to be included if a future
need is identified. This does not cause an
interoperability concern because unrecognized signed
attributes are ignored by the relying party.</t>
<t>The signedAttr MUST include only a single instance of
any particular attribute. Additionally, even though the
syntax allows for a SET OF AttributeValue, in a BOA the
attrValues must consist of only a single
AttributeValue.</t>
<section title="Content-Type Attribute">
<t>The ContentType attribute MUST be present. The
attrType OID for the ContentType attribute is
1.2.840.113549.1.9.3.</t>
<t>The attrValues for the ContentType attribute in a ROA
MUST be 1.2.840.113549.1.9.16.1.[TBD] (matching the
eContentType in the EncapsulatedContentInfo).</t>
</section>
<section title="Message-Digest Attribute">
<t>The MessageDigest Attribute MUST be present. The
attrType OID for the MessageDigest Attribute is
1.2.840.113549.1.9.4.</t>
<t>The attrValues for the MessageDigest attribute
contains the output of the digest algorithm applied to
the content being signed, as specified in Section 11.1
of<xref target="RFC3852"></xref>.</t>
</section>
<section title="Signing-Time Attribute">
<t>The SigningTime Attribute MAY be present in a BOA. If
it is present it MUST be ignored by the relying
party. The presence of absence of the SigningTime
attribute in no way affects the validation of the BOA
(as specified in Section 3). The attrType OID for the
SigningTime attribute is 1.2.840.113549.1.9.5.</t>
<t>The SigningTime attribute is defined as:</t>
<figure>
<artwork><![CDATA[
id-signingTime OBJECT IDENTIFIER ::= { iso(1) member-body(2)
us(840) rsadsi(113549) pkcs(1) pkcs9(9) 5 }
SigningTime ::= Time
Time ::= CHOICE {
utcTime UTCTime,
generalizedTime GeneralizedTime }
]]></artwork>
</figure>
<t>The Time element specifies the time, based on the
local system clock, at which the digital signature was
applied to the content.</t>
</section>
<section title="BinarySigningTime Attribute">
<t>The BinarySigningTime Attribute MAY be present. If it
is present it MUST be ignored by the relying party. The
presence of absence of the BinarySigningTime attribute
in no way affects the validation of the ROA (as
specified in Section 3). The attrType OID for the
BinarySigningTime attribute is
1.2.840.113549.1.9.16.2.46.</t>
<t>The BinarySigningTime attribute is defined as:</t>
<figure>
<artwork><![CDATA[
id-aa-binarySigningTime OBJECT IDENTIFIER ::= { iso(1)
member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
smime(16) aa(2) 46 }
BinarySigningTime ::= BinaryTime
BinaryTime ::= INTEGER (0..MAX)
]]></artwork>
</figure>
<t>The BinaryTime element specifies the time, based on
the local system clock, at which the digital signature
was applied to the content.</t>
</section>
</section>
<section title="signatureAlgorithm">
<t>The signatureAlgorithm MUST be RSA (rsaEncryption), the OID for
which is 1.2.840.113549.1.1.1.</t>
</section>
<section title="signature">
<t>The signature value is defined as:</t>
<figure>
<artwork><![CDATA[
SignatureValue ::= OCTET STRING
]]></artwork>
</figure>
<t>The signature characteristics are defined by the digest
and signature algorithms.</t>
</section>
<section title="unsignedAttrs">
<t>unsignedAttrs MUST be omitted.</t>
</section>
</section>
</section>
</section>
<section title="BOA Validation">
<t>Before a relying party can use a BOA as a constrictor of a routing
announcement, the relying party must use the RPKI to validate the BOA.
To do this the relying party performs the following steps:<vspace
blankLines="1" /> <list style="numbers">
<t>Verify that the BOA syntax complies with this specification. In
particular, verify the following:<vspace blankLines="1" /> <list
style="format %c.">
<t>The contentType of the CMS object is SignedData (OID
1.2.840.113549.1.7.2)<vspace blankLines="1" /></t>
<t>The eContentType of the CMS object is id-ct-rpkiBOA (OID
1.2.840.113549.1.9.16.1.[TBD]) <vspace blankLines="1" /></t>
<t>The version of the SignedData object is 3.<vspace
blankLines="1" /></t>
<t>The digestAlgorithm in the SignedData object is SHA-256 (OID
2.16.840.1.101.3.4.2.1).<vspace blankLines="1" /></t>
<t>The certificates field in the SignedData object is present
and contains an EE certificate whose Subject Key Identifier
(SKI) matches the sid field of the SignerInfo object. <vspace
blankLines="1" /></t>
<t>The crls field in the SignedData object is omitted.<vspace
blankLines="1" /></t>
<t>The eContentType in the EncapsulatedContentInfo is
rid-ct-rpkiBOA (OID 1.2.840.113549.1.9.16.1.[TBD]) <vspace
blankLines="1" /></t>
<t>The version of the BOA is 0.<vspace blankLines="1" /></t>
<t>The addressFamily in the BOAIPAddressFamily is either IPv4 or
IPv6 (0001 and 0002, respectively).<vspace blankLines="1" /></t>
<t>The version of the SignerInfo is 3.<vspace
blankLines="1" /></t>
<t>The digestAlgorithm in the SignerInfo object is SHA-256 (OID
2.16.840.1.101.3.4.2.1).<vspace blankLines="1" /></t>
<t>The signatureAlgorithm in the SignerInfo object is RSA (OID
1.2.840.113549.1.1.1).<vspace blankLines="1" /></t>
<t>The signedAttrs field in the SignerInfo object is present and
contains both the ContentType attribute (OID
1.2.840.113549.1.9.3) and the MessageDigest attribute (OID
1.2.840.113549.1.9.4). .<vspace blankLines="1" /></t>
<t>The unsignedAttrs field in the SignerInfo object is
omitted.<vspace blankLines="1" /></t>
</list></t>
<t>Use the public key in the EE certificate to verify the signature
on the BOA.<vspace blankLines="1" /></t>
<t>Verify that the EE certificate has an IP Address Delegation
extension <xref target="RFC3779"></xref> and that the IP address
prefixes in that extension exactly match the IP address prefixes in
the BOA, and the AS numbers in that extension exactly match the AS
numbers in the BOA.<vspace blankLines="1" /></t>
<t>Verify that the EE certificate is a valid end-entity certificate
in the resource PKI by constructing a valid certificate path to a
trust anchor. (See <xref target="ID.ietf-sidr-res-certs"></xref> for
more details.)</t>
</list></t>
<t>Note that requiring an exact match between the IP address
prefixes and AS's in a BOA and the IP address prefixes and AS's
in the corresponding EE certificate does not place any
limitations on BOA use. Since each EE certificate in the RPKI
architecture is used to verify only a single BOA, it is natural
to have the IP address prefixes in the certificate match those
in the corresponding BOA.</t>
</section>
<section title="BOA Use Practices">
<t>BOAs are intended to allow relying parties a means of
validating whether route origination information as described in
a route advertisement refers to an IP address or AS number that
has not been validly allocated for use in the routing
system.</t>
<t>Any party with a validly assigned Internet resource set and a
CA certificate that describes this delegation can publish a BOA,
independently of the actions of the actions of the party that
assigned the resource set.</t>
<t>BOAs are not hierarchically related.</t>
<t>An Internet Registry SHOULD maintain a single BOA in relation
to each parent registry that has assigned resources to this
registry.</t>
<t>An Internet Registry SHOULD maintain a regular issuance cycle
for BOAs.</t>
<t>For registries that operate on a day-to-day basis in terms of
resource transactions, it is suggested that a local BOA
management practice would be that a new BOA should be issued on
a regular 24 hour basis. The corresponding EE certificate should
have a validity period of no more than 72 hours from the time of
issuance. Each time a new EE certificate for a BOA is issued the
previous BOA's EE certificate should be revoked and the previous
BOA removed from the publication repository.</t>
<t>Parties that operate a local cache of RPKI objects should
ensure that they refresh BOA objects at intervals 24 hours to
ensure that they have the current BOA in the local cache.</t>
</section>
<section title="BOA Interpretation">
<t>A BOA can be used to check a route object to determine if the
origination information in the route object refers to invalid IP
addresses or an invalid AS number.</t>
<t>If a route object has an AS origination that refers to an AS
number that is included in a valid BOA then the route object can
be regarded as a Bogon object, and local policies that apply to
Bogon AS's can be applied to the object. This holds whether or
not the address prefix of the route object is described by a
valid ROA or not.</t>
<t>If a route object has an address prefix that is equal to, or
is a more specific prefix of an IP address that is included in a
valid BOA then the route object can be regarded as a Bogon
object, and local policies that apply to Bogon AS's can be
applied to the object, unless the address prefix and AS
origination of the route object is also described by a valid
ROA, in which case the BOA is to be disregarded. In other words
a valid ROA SHOULD infer a higher trust preference than a ROA if
a valid ROA and BOA exist for the same address prefix and AS
number.</t>
</section>
<section title="Security Considerations">
<t>There is no assumption of confidentiality for the data in a
BOA; it is anticipated that BOAs will be stored in repositories
that are accessible to all ISPs, and perhaps to all Internet
users. There is no explicit authentication associated with a
BOA, since the RPKI used for BOA validation provides
authorization but not authentication. Although the BOA is a
signed, application layer object, there is no intent to convey
non-repudiation via a BOA.</t>
<t>The purpose of a BOA is to convey an attestation by an
address holder that there is no authority for the generation of
a route object that refers to specified addresses or origination
from specified AS's. The integrity of a BOA must be established
in order to validate the authority of the Bogon Attestation. The
BOA makes use of the CMS signed message format for integrity,
and thus inherits the security considerations associated with
that data structure. The right of the BOA signer to authorize
the attestation of specified IP addresses and AS's as Bogons is
established through use of the address space and AS number PKI
described in <xref target="ID.ietf-sidr-arch" />. Specifically,
a relying party must verify the signature on the BOA using an
X.509 certificate issued under this PKI, and check that the
prefix(es) in the BOA match those in the address space extension
in the certificate.</t>
</section>
<section title="IANA Considerations">
<t>[None]</t>
</section>
<section title="Acknowledgments">
<t>The authors are indebted to the authors of Route Origin
Authorization (ROA) <xref
target="ID.ietf-sidr-roa-format"></xref>, M. Lepinski, S. Kent
and D. Kong, as much of the text used to define a BOA has been
borrowed from the ROA format specification, and Russ Housley for
clarification on the CMS profile.</t>
</section>
</middle>
<back>
<references title="Normative References">
<reference anchor="ID.ietf-sidr-arch">
<front>
<title>An Infrastructure to Support Secure Internet Routing</title>
<author fullname="M. Lepinski" initials="M" surname="Lepinski">
<organization>BBN Technologies</organization>
</author>
<author fullname="S. Kent" initials="S" surname="Kent">
<organization>BBN Technologies</organization>
</author>
<date day="25" month="February" year="2008" />
</front>
<seriesInfo name="Internet-Draft" value="draft-ietf-sidr-arch" />
<format target="http://draft-ietf-sidr-arch.potaroo.net" type="TXT" />
</reference>
<reference anchor="ID.ietf-sidr-res-certs">
<front>
<title>A Profile for X.509 PKIX Resource Certificates</title>
<author fullname="G. Huston" initials="G" surname="Huston">
<organization>APNIC</organization>
</author>
<author fullname="G. Michaelson" initials="G" surname="Michaleson">
<organization>APNIC</organization>
</author>
<author fullname="R. Loomans" initials="R" surname="Loomans">
<organization>APNIC</organization>
</author>
<date day="1" month="August" year="2008" />
</front>
<seriesInfo name="Internet Draft"
value="draft-ietf-sidr-res-certs" />
<format target="http://draft-ietf-sidr-recerts.potaroo.net" type="TXT" />
</reference>
<reference anchor="ID.ietf-sidr-roa-format">
<front>
<title>An Infrastructure to Support Secure Internet Routing</title>
<author fullname="M. Lepinski" initials="M" surname="Lepinski">
<organization>BBN Technologies</organization>
</author>
<author fullname="S. Kent" initials="S" surname="Kent">
<organization>BBN Technologies</organization>
</author>
<author fullname="D. Kong" initials="D" surname="Kong">
<organization>BBN Technologies</organization>
</author>
<date day="7" month="July" year="2008" />
</front>
<seriesInfo name="Internet-Draft" value="draft-ietf-sidr-roa-format" />
<format target="http://draft-ietf-sidr-roa-format.potaroo.net"
type="TXT" />
</reference>
<?rfc include='./rfcs/bibxml/reference.RFC.3779.xml'?>
<?rfc include='./rfcs/bibxml/reference.RFC.3852.xml'?>
<?rfc include='./rfcs/bibxml/reference.RFC.4055.xml'?>
<?rfc include='./rfcs/bibxml/reference.RFC.4271.xml'?>
<?rfc include='./rfcs/bibxml/reference.RFC.5280.xml'?>
</references>
</back>
</rfc>
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