One document matched: draft-ietf-sidr-bogons-00.xml
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<rfc category="std" docName="draft-ietf-sidr-bogons-00.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="Terry Manderson" initials="T." surname="Manderson">
<organization abbrev="APNIC">Asia Pacific Network Information
Centre</organization>
<address>
<email>terry@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>
<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, and also provides a means of
verifying that BGP speaker is not using an AS as a BGP speaker 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 BGP.</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 ASes in a
routing advertisement in the Border Gateway Protocol (BGP) <xref
target="RFC4271"></xref> should be considered an invalid use of such
addresses or ASes.</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"></xref>, and
allows a resource holder to explicitly list those IP addresses and ASes
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"></xref> 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
has 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 INDENTIFIER ::= { 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 ASes and
a list of 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 ASes 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 ASes. 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 VinarySigningTime 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 1.%c">
<t>The contentType of the CMS object is SignedData (OID
1.2.840.113549.1.7.2)</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="0" /></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="0" /></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 ASes in a BOA and the IP address prefixes and ASes 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 ASes 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 ASes 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 ASes. 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 ASes
as Bogons is established through use of the address space and AS number
PKI described in <xref target="ID.ietf-sidr-arch"></xref>. 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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