draft-ietf-sidr-bgpsec-protocol-18.txt   draft-ietf-sidr-bgpsec-protocol-19.txt 
Network Working Group M. Lepinski, Ed. Network Working Group M. Lepinski, Ed.
Internet-Draft NCF Internet-Draft NCF
Intended status: Standards Track K. Sriram, Ed. Intended status: Standards Track K. Sriram, Ed.
Expires: February 19, 2017 NIST Expires: May 31, 2017 NIST
August 18, 2016 November 27, 2016
BGPsec Protocol Specification BGPsec Protocol Specification
draft-ietf-sidr-bgpsec-protocol-18 draft-ietf-sidr-bgpsec-protocol-19
Abstract Abstract
This document describes BGPsec, an extension to the Border Gateway This document describes BGPsec, an extension to the Border Gateway
Protocol (BGP) that provides security for the path of autonomous Protocol (BGP) that provides security for the path of autonomous
systems through which a BGP update message passes. BGPsec is systems through which a BGP update message passes. BGPsec is
implemented via an optional non-transitive BGP path attribute that implemented via an optional non-transitive BGP path attribute that
carries a digital signature produced by each autonomous system that carries a digital signature produced by each autonomous system that
propagates the update message. propagates the update message.
skipping to change at page 1, line 36 skipping to change at page 1, line 36
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on February 19, 2017. This Internet-Draft will expire on May 31, 2017.
Copyright Notice Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. BGPsec Negotiation . . . . . . . . . . . . . . . . . . . . . 3 2. BGPsec Negotiation . . . . . . . . . . . . . . . . . . . . . 3
2.1. The BGPsec Capability . . . . . . . . . . . . . . . . . . 3 2.1. The BGPsec Capability . . . . . . . . . . . . . . . . . . 3
2.2. Negotiating BGPsec Support . . . . . . . . . . . . . . . 4 2.2. Negotiating BGPsec Support . . . . . . . . . . . . . . . 4
3. The BGPsec_Path Attribute . . . . . . . . . . . . . . . . . . 6 3. The BGPsec_Path Attribute . . . . . . . . . . . . . . . . . . 6
3.1. Secure_Path . . . . . . . . . . . . . . . . . . . . . . . 8 3.1. Secure_Path . . . . . . . . . . . . . . . . . . . . . . . 8
3.2. Signature_Block . . . . . . . . . . . . . . . . . . . . . 9 3.2. Signature_Block . . . . . . . . . . . . . . . . . . . . . 9
4. BGPsec Update Messages . . . . . . . . . . . . . . . . . . . 10 4. BGPsec Update Messages . . . . . . . . . . . . . . . . . . . 11
4.1. General Guidance . . . . . . . . . . . . . . . . . . . . 11 4.1. General Guidance . . . . . . . . . . . . . . . . . . . . 11
4.2. Constructing the BGPsec_Path Attribute . . . . . . . . . 13 4.2. Constructing the BGPsec_Path Attribute . . . . . . . . . 13
4.3. Processing Instructions for Confederation Members . . . . 17 4.3. Processing Instructions for Confederation Members . . . . 17
4.4. Reconstructing the AS_PATH Attribute . . . . . . . . . . 19 4.4. Reconstructing the AS_PATH Attribute . . . . . . . . . . 19
5. Processing a Received BGPsec Update . . . . . . . . . . . . . 20 5. Processing a Received BGPsec Update . . . . . . . . . . . . . 21
5.1. Overview of BGPsec Validation . . . . . . . . . . . . . . 22 5.1. Overview of BGPsec Validation . . . . . . . . . . . . . . 23
5.2. Validation Algorithm . . . . . . . . . . . . . . . . . . 23 5.2. Validation Algorithm . . . . . . . . . . . . . . . . . . 24
6. Algorithms and Extensibility . . . . . . . . . . . . . . . . 26 6. Algorithms and Extensibility . . . . . . . . . . . . . . . . 27
6.1. Algorithm Suite Considerations . . . . . . . . . . . . . 26 6.1. Algorithm Suite Considerations . . . . . . . . . . . . . 27
6.2. Extensibility Considerations . . . . . . . . . . . . . . 27 6.2. Extensibility Considerations . . . . . . . . . . . . . . 28
7. Security Considerations . . . . . . . . . . . . . . . . . . . 28 7. Operations and Management Considerations . . . . . . . . . . 29
7.1. Security Guarantees . . . . . . . . . . . . . . . . . . . 28 8. Security Considerations . . . . . . . . . . . . . . . . . . . 30
7.2. On the Removal of BGPsec Signatures . . . . . . . . . . . 29 8.1. Security Guarantees . . . . . . . . . . . . . . . . . . . 31
7.3. Mitigation of Denial of Service Attacks . . . . . . . . . 30 8.2. On the Removal of BGPsec Signatures . . . . . . . . . . . 31
7.4. Additional Security Considerations . . . . . . . . . . . 31 8.3. Mitigation of Denial of Service Attacks . . . . . . . . . 33
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 31 8.4. Additional Security Considerations . . . . . . . . . . . 34
9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 32 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 35
9.1. Authors . . . . . . . . . . . . . . . . . . . . . . . . . 32 10. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 36
9.2. Acknowledgements . . . . . . . . . . . . . . . . . . . . 33 10.1. Authors . . . . . . . . . . . . . . . . . . . . . . . . 36
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 33 10.2. Acknowledgements . . . . . . . . . . . . . . . . . . . . 37
10.1. Normative References . . . . . . . . . . . . . . . . . . 33 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 37
10.2. Informative References . . . . . . . . . . . . . . . . . 34 11.1. Normative References . . . . . . . . . . . . . . . . . . 37
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 35 11.2. Informative References . . . . . . . . . . . . . . . . . 38
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 40
1. Introduction 1. Introduction
This document describes BGPsec, a mechanism for providing path This document describes BGPsec, a mechanism for providing path
security for Border Gateway Protocol (BGP) [RFC4271] route security for Border Gateway Protocol (BGP) [RFC4271] route
advertisements. That is, a BGP speaker who receives a valid BGPsec advertisements. That is, a BGP speaker who receives a valid BGPsec
update has cryptographic assurance that the advertised route has the update has cryptographic assurance that the advertised route has the
following property: Every AS on the path of ASes listed in the update following property: Every AS on the path of ASes listed in the update
message has explicitly authorized the advertisement of the route to message has explicitly authorized the advertisement of the route to
the subsequent AS in the path. the subsequent AS in the path.
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speaker to advertise to a neighbor the ability to send or to receive speaker to advertise to a neighbor the ability to send or to receive
BGPsec update messages (i.e., update messages containing the BGPsec update messages (i.e., update messages containing the
BGPsec_Path attribute). BGPsec_Path attribute).
2.1. The BGPsec Capability 2.1. The BGPsec Capability
This capability has capability code : TBD This capability has capability code : TBD
The capability length for this capability MUST be set to 3. The capability length for this capability MUST be set to 3.
The three octets of the capability value are specified as follows. The three octets of the capability format are specified in Figure 1.
BGPsec Send Capability Value
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+---------------------------------------+ +---------------------------------------+
| Version | Dir | Reserved | | Version | Dir | Reserved |
+---------------------------------------+ +---------------------------------------+
| | | |
+------ AFI -----+ +------ AFI -----+
| | | |
+---------------------------------------+ +---------------------------------------+
Figure 1: BGPsec Capability format.
The first four bits of the first octet indicate the version of BGPsec The first four bits of the first octet indicate the version of BGPsec
for which the BGP speaker is advertising support. This document for which the BGP speaker is advertising support. This document
defines only BGPsec version 0 (all four bits set to zero). Other defines only BGPsec version 0 (all four bits set to zero). Other
versions of BGPsec may be defined in future documents. A BGPsec versions of BGPsec may be defined in future documents. A BGPsec
speaker MAY advertise support for multiple versions of BGPsec by speaker MAY advertise support for multiple versions of BGPsec by
including multiple versions of the BGPsec capability in its BGP OPEN including multiple versions of the BGPsec capability in its BGP OPEN
message. message.
The fifth bit of the first octet is a direction bit which indicates The fifth bit of the first octet is a direction bit which indicates
whether the BGP speaker is advertising the capability to send BGPsec whether the BGP speaker is advertising the capability to send BGPsec
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the BGPsec_Path attribute (for a particular address family), a BGP the BGPsec_Path attribute (for a particular address family), a BGP
speaker sends the BGPsec capability with the Direction bit set to 0. speaker sends the BGPsec capability with the Direction bit set to 0.
In order to advertise the capability to both send and receive BGPsec In order to advertise the capability to both send and receive BGPsec
update messages, the BGP speaker sends two copies of the BGPsec update messages, the BGP speaker sends two copies of the BGPsec
capability (one with the direction bit set to 0 and one with the capability (one with the direction bit set to 0 and one with the
direction bit set to 1). direction bit set to 1).
Similarly, if a BGP speaker wishes to use BGPsec with two different Similarly, if a BGP speaker wishes to use BGPsec with two different
address families (i.e., IPv4 and IPv6) over the same BGP session, address families (i.e., IPv4 and IPv6) over the same BGP session,
then the speaker includes two instances of this capability (one for then the speaker includes two instances of this capability (one for
each address family) in the BGP OPEN message. A BGP speaker MUST each address family) in the BGP OPEN message. A BGP speaker MAY
support the BGP multiprotocol extension [RFC4760]. Additionally, a announce BGPsec capability only if it supports the BGP multiprotocol
BGP speaker MUST NOT advertise the capability of BGPsec support for a extension [RFC4760]. Additionally, a BGP speaker MUST NOT advertise
particular AFI unless it has also advertised the multiprotocol the capability of BGPsec support for a particular AFI unless it has
extension capability for the same AFI [RFC4760]. also advertised the multiprotocol extension capability for the same
AFI [RFC4760].
In a BGPsec peering session, a peer is permitted to send update In a BGPsec peering session, a peer is permitted to send update
messages containing the BGPsec_Path attribute if, and only if: messages containing the BGPsec_Path attribute if, and only if:
o The given peer sent the BGPsec capability for a particular version o The given peer sent the BGPsec capability for a particular version
of BGPsec and a particular address family with the Direction bit of BGPsec and a particular address family with the Direction bit
set to 1; and set to 1; and
o The other (receiving) peer sent the BGPsec capability for the same o The other (receiving) peer sent the BGPsec capability for the same
version of BGPsec and the same address family with the Direction version of BGPsec and the same address family with the Direction
bit set to 0. bit set to 0.
In such a session, we say that the use of the particular version of In such a session, it can be said that the use of the particular
BGPsec has been negotiated for a particular address family. BGP version of BGPsec has been negotiated for a particular address
update messages without the BGPsec_Path attribute MAY be sent within family. BGP update messages without the BGPsec_Path attribute MAY be
a session regardless of whether or not the use of BGPsec is sent within a session regardless of whether or not the use of BGPsec
successfully negotiated. However, if BGPsec is not successfully is successfully negotiated. However, if BGPsec is not successfully
negotiated, then BGP update messages containing the BGPsec_Path negotiated, then BGP update messages containing the BGPsec_Path
attribute MUST NOT be sent. attribute MUST NOT be sent.
This document defines the behavior of implementations in the case This document defines the behavior of implementations in the case
where BGPsec version zero is the only version that has been where BGPsec version zero is the only version that has been
successfully negotiated. Any future document which specifies successfully negotiated. Any future document which specifies
additional versions of BGPsec will need to specify behavior in the additional versions of BGPsec will need to specify behavior in the
case that support for multiple versions is negotiated. case that support for multiple versions is negotiated.
BGPsec cannot provide meaningful security guarantees without support BGPsec cannot provide meaningful security guarantees without support
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Note that BGPsec update messages can be quite large, therefore any Note that BGPsec update messages can be quite large, therefore any
BGPsec speaker announcing the capability to receive BGPsec messages BGPsec speaker announcing the capability to receive BGPsec messages
SHOULD also announce support for the capability to receive BGP SHOULD also announce support for the capability to receive BGP
extended messages [I-D.ietf-idr-bgp-extended-messages]. extended messages [I-D.ietf-idr-bgp-extended-messages].
3. The BGPsec_Path Attribute 3. The BGPsec_Path Attribute
The BGPsec_Path attribute is an optional non-transitive BGP path The BGPsec_Path attribute is an optional non-transitive BGP path
attribute. attribute.
This document registers an attribute type code for this attribute : This document registers an attribute type code for this attribute:
TBD BGPsec_Path (see Section 9).
The BGPsec_Path attribute carries the secured information regarding The BGPsec_Path attribute carries the secured information regarding
the path of ASes through which an update message passes. This the path of ASes through which an update message passes. This
includes the digital signatures used to protect the path information. includes the digital signatures used to protect the path information.
We refer to those update messages that contain the BGPsec_Path The update messages that contain the BGPsec_Path attribute are
attribute as "BGPsec Update messages". The BGPsec_Path attribute referred to as "BGPsec Update messages". The BGPsec_Path attribute
replaces the AS_PATH attribute in a BGPsec update message. That is, replaces the AS_PATH attribute in a BGPsec update message. That is,
update messages that contain the BGPsec_Path attribute MUST NOT update messages that contain the BGPsec_Path attribute MUST NOT
contain the AS_PATH attribute, and vice versa. contain the AS_PATH attribute, and vice versa.
The BGPsec_Path attribute is made up of several parts. The following The BGPsec_Path attribute is made up of several parts. The high-
high-level diagram provides an overview of the structure of the level diagram in Figure 2 provides an overview of the structure of
BGPsec_Path attribute: the BGPsec_Path attribute.
High-Level Diagram of the BGPsec_Path Attribute
+---------------------------------------------------------+ +---------------------------------------------------------+
| +-----------------+ | | +-----------------+ |
| | Secure Path | | | | Secure Path | |
| +-----------------+ | | +-----------------+ |
| | AS X | | | | AS X | |
| | pCount X | | | | pCount X | |
| | Flags X | | | | Flags X | |
| | AS Y | | | | AS Y | |
| | pCount Y | | | | pCount Y | |
skipping to change at page 7, line 33 skipping to change at page 7, line 31
| | Alg Suite 1 | | Alg Suite 2 | | | | Alg Suite 1 | | Alg Suite 2 | |
| | SKI X1 | | SKI X1 | | | | SKI X1 | | SKI X1 | |
| | Signature X1 | | Signature X1 | | | | Signature X1 | | Signature X1 | |
| | SKI Y1 | | SKI Y1 | | | | SKI Y1 | | SKI Y1 | |
| | Signature Y1 | | Signature Y1 | | | | Signature Y1 | | Signature Y1 | |
| | ... | | .... | | | | ... | | .... | |
| +-----------------+ +-----------------+ | | +-----------------+ +-----------------+ |
| | | |
+---------------------------------------------------------+ +---------------------------------------------------------+
The following is the specification of the format for the BGPsec_Path Figure 2: High-level diagram of the BGPsec_Path attribute.
attribute.
BGPsec_Path Attribute Figure 3 provides the specification of the format for the BGPsec_Path
attribute.
+-------------------------------------------------------+ +-------------------------------------------------------+
| Secure_Path (variable) | | Secure_Path (variable) |
+-------------------------------------------------------+ +-------------------------------------------------------+
| Sequence of one or two Signature_Blocks (variable) | | Sequence of one or two Signature_Blocks (variable) |
+-------------------------------------------------------+ +-------------------------------------------------------+
Figure 3: BGPsec_Path attribute format.
The Secure_Path contains AS path information for the BGPsec update The Secure_Path contains AS path information for the BGPsec update
message. This is logically equivalent to the information that is message. This is logically equivalent to the information that is
contained in a non-BGPsec AS_PATH attribute. The information in contained in a non-BGPsec AS_PATH attribute. The information in
Secure_Path is used by BGPsec speakers in the same way that Secure_Path is used by BGPsec speakers in the same way that
information from the AS_PATH is used by non-BGPsec speakers. The information from the AS_PATH is used by non-BGPsec speakers. The
format of the Secure_Path is described below in Section 3.1. format of the Secure_Path is described below in Section 3.1.
The BGPsec_Path attribute will contain one or two Signature_Blocks, The BGPsec_Path attribute will contain one or two Signature_Blocks,
each of which corresponds to a different algorithm suite. Each of each of which corresponds to a different algorithm suite. Each of
the Signature_Blocks will contain a signature segment for each AS the Signature_Blocks will contain a signature segment for each AS
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Signature_Block. However, in order to enable a transition from an Signature_Block. However, in order to enable a transition from an
old algorithm suite to a new algorithm suite (without a flag day), it old algorithm suite to a new algorithm suite (without a flag day), it
will be necessary to include two Signature_Blocks (one for the old will be necessary to include two Signature_Blocks (one for the old
algorithm suite and one for the new algorithm suite) during the algorithm suite and one for the new algorithm suite) during the
transition period. (See Section 6.1 for more discussion of algorithm transition period. (See Section 6.1 for more discussion of algorithm
transitions.) The format of the Signature_Blocks is described below transitions.) The format of the Signature_Blocks is described below
in Section 3.2. in Section 3.2.
3.1. Secure_Path 3.1. Secure_Path
Here we provide a detailed description of the Secure_Path information A detailed description of the Secure_Path information in the
in the BGPsec_Path attribute. BGPsec_Path attribute is provided here.
Secure_Path
+-----------------------------------------------+ +-----------------------------------------------+
| Secure_Path Length (2 octets) | | Secure_Path Length (2 octets) |
+-----------------------------------------------+ +-----------------------------------------------+
| One or More Secure_Path Segments (variable) | | One or More Secure_Path Segments (variable) |
+-----------------------------------------------+ +-----------------------------------------------+
The Secure_Path Length contains the length (in octets) of the entire Figure 4: Secure_Path format.
Secure_Path (including the two octets used to express this length
field). As explained below, each Secure_Path segment is six octets
long. Note that this means the Secure_Path Length is two greater
than six times the number Secure_Path Segments (i.e., the number of
AS numbers in the path).
The Secure_Path contains one Secure_Path Segment for each Autonomous The specification for the Secure_Path field is provided in Figure 4
System in the path to the originating AS of the NLRI specified in the and Figure 5. The Secure_Path Length contains the length (in octets)
update message. of the entire Secure_Path (including the two octets used to express
this length field). As explained below, each Secure_Path segment is
six octets long. Note that this means the Secure_Path Length is two
greater than six times the number Secure_Path Segments (i.e., the
number of AS numbers in the path).
Secure_Path Segment The Secure_Path contains one Secure_Path Segment (see Figure 5) for
each Autonomous System in the path to the originating AS of the
prefix specified in the update message. (Note: Repeated Autonomous
Systems are compressed out using the pCount field as discussed
below).
+----------------------------+ +----------------------------+
| pCount (1 octet) | | pCount (1 octet) |
+----------------------------+ +----------------------------+
| Flags (1 octet) | | Flags (1 octet) |
+----------------------------+ +----------------------------+
| AS Number (4 octets) | | AS Number (4 octets) |
+----------------------------+ +----------------------------+
The AS Number is the AS number of the BGP speaker that added this Figure 5: Secure_Path Segment format.
Secure_Path segment to the BGPsec_Path attribute. (See Section 4 for
more information on populating this field.) The AS Number (in Figure 5) is the AS number of the BGP speaker that
added this Secure_Path segment to the BGPsec_Path attribute. (See
Section 4 for more information on populating this field.)
The pCount field contains the number of repetitions of the associated The pCount field contains the number of repetitions of the associated
autonomous system number that the signature covers. This field autonomous system number that the signature covers. This field
enables a BGPsec speaker to mimic the semantics of prepending enables a BGPsec speaker to mimic the semantics of prepending
multiple copies of their AS to the AS_PATH without requiring the multiple copies of their AS to the AS_PATH without requiring the
speaker to generate multiple signatures. The pCount field is also speaker to generate multiple signatures. Note that Section 9.1.2.2
useful in managing route servers (see Section 4.2) and AS Number ("Breaking Ties") in [RFC4271] mentions "number of AS numbers" in the
migrations, see [I-D.ietf-sidr-as-migration] for details. AS_PATH attribute that is used in the route selection process. This
metric (number of AS numbers) is the same as the AS path length
obtained in BGPsec by summing the pCount values in the BGPsec_Path
attribute. The pCount field is also useful in managing route servers
(see Section 4.2) and AS Number migrations, see
[I-D.ietf-sidr-as-migration] for details.
The first bit of the Flags field is the Confed_Segment flag. The The left most (i.e. the most significant) bit of the Flags field in
Confed_Segment flag is set to one to indicate that the BGPsec speaker Figure 5 is the Confed_Segment flag. The Confed_Segment flag is set
that constructed this Secure_Path segment is sending the update to one to indicate that the BGPsec speaker that constructed this
message to a peer AS within the same Autonomous System confederation Secure_Path segment is sending the update message to a peer AS within
[RFC5065]. (That is, the Confed_Segment flag is set in a BGPsec the same Autonomous System confederation [RFC5065]. (That is, the
update message whenever, in a non-BGPsec update message, the BGP Confed_Segment flag is set in a BGPsec update message whenever, in a
speaker's AS would appear in a AS_PATH segment of type non-BGPsec update message, the BGP speaker's AS would appear in a
AS_CONFED_SEQUENCE.) In all other cases the Confed_Segment flag is AS_PATH segment of type AS_CONFED_SEQUENCE.) In all other cases the
set to zero. Confed_Segment flag is set to zero.
The remaining seven bits of the Flags MUST be set to zero by the The remaining seven bits of the Flags MUST be set to zero by the
sender, and ignored by the receiver. Note, however, that the sender, and ignored by the receiver. Note, however, that the
signature is computed over all eight bits of the flags field. signature is computed over all eight bits of the flags field.
3.2. Signature_Block 3.2. Signature_Block
Here we provide a detailed description of the Signature_Blocks in the A detailed description of the Signature_Blocks in the BGPsec_Path
BGPsec_Path attribute. attribute is provided here using Figure 6 and Figure 7.
Signature_Block
+---------------------------------------------+ +---------------------------------------------+
| Signature_Block Length (2 octets) | | Signature_Block Length (2 octets) |
+---------------------------------------------+ +---------------------------------------------+
| Algorithm Suite Identifier (1 octet) | | Algorithm Suite Identifier (1 octet) |
+---------------------------------------------+ +---------------------------------------------+
| Sequence of Signature Segments (variable) | | Sequence of Signature Segments (variable) |
+---------------------------------------------+ +---------------------------------------------+
The Signature_Block Length is the total number of octets in the Figure 6: Signature_Block format.
Signature_Block (including the two octets used to express this length
field). The Signature_Block Length in Figure 6 is the total number of octets
in the Signature_Block (including the two octets used to express this
length field).
The Algorithm Suite Identifier is a one-octet identifier specifying The Algorithm Suite Identifier is a one-octet identifier specifying
the digest algorithm and digital signature algorithm used to produce the digest algorithm and digital signature algorithm used to produce
the digital signature in each Signature Segment. An IANA registry of the digital signature in each Signature Segment. An IANA registry of
algorithm identifiers for use in BGPsec is specified in the BGPsec algorithm identifiers for use in BGPsec is specified in the BGPsec
algorithms document [I-D.ietf-sidr-bgpsec-algs]. algorithms document [I-D.ietf-sidr-bgpsec-algs].
A Signature_Block has exactly one Signature Segment for each A Signature_Block in Figure 6 has exactly one Signature Segment (see
Secure_Path Segment in the Secure_Path portion of the BGPsec_Path Figure 7) for each Secure_Path Segment in the Secure_Path portion of
Attribute. (That is, one Signature Segment for each distinct AS on the BGPsec_Path Attribute. (That is, one Signature Segment for each
the path for the NLRI in the Update message.) distinct AS on the path for the prefix in the Update message.)
Signature Segments
+---------------------------------------------+ +---------------------------------------------+
| Subject Key Identifier (20 octets) | | Subject Key Identifier (SKI) (20 octets) |
+---------------------------------------------+ +---------------------------------------------+
| Signature Length (2 octets) | | Signature Length (2 octets) |
+---------------------------------------------+ +---------------------------------------------+
| Signature (variable) | | Signature (variable) |
+---------------------------------------------+ +---------------------------------------------+
The Subject Key Identifier contains the value in the Subject Key Figure 7: Signature Segment format.
Identifier extension of the RPKI router certificate
[I-D.ietf-sidr-bgpsec-pki-profiles] that is used to verify the The Subject Key Identifier (SKI) field in Figure 7 contains the value
signature (see Section 5 for details on validity of BGPsec update in the Subject Key Identifier extension of the RPKI router
messages). certificate [I-D.ietf-sidr-bgpsec-pki-profiles] that is used to
verify the signature (see Section 5 for details on validity of BGPsec
update messages).
The Signature Length field contains the size (in octets) of the value The Signature Length field contains the size (in octets) of the value
in the Signature field of the Signature Segment. in the Signature field of the Signature Segment.
The Signature contains a digital signature that protects the NLRI and The Signature in Figure 7 contains a digital signature that protects
the BGPsec_Path attribute (see Section 4 and Section 5 for details on the prefix and the BGPsec_Path attribute (see Section 4 and Section 5
signature generation and validation, respectively). for details on signature generation and validation, respectively).
4. BGPsec Update Messages 4. BGPsec Update Messages
Section 4.1 provides general guidance on the creation of BGPsec Section 4.1 provides general guidance on the creation of BGPsec
Update Messages -- that is, update messages containing the Update Messages -- that is, update messages containing the
BGPsec_Path attribute. BGPsec_Path attribute.
Section 4.2 specifies how a BGPsec speaker generates the BGPsec_Path Section 4.2 specifies how a BGPsec speaker generates the BGPsec_Path
attribute to include in a BGPsec Update message. attribute to include in a BGPsec Update message.
Section 4.3 contains special processing instructions for members of Section 4.3 contains special processing instructions for members of
an autonomous system confederation [RFC5065]. A BGPsec speaker that an autonomous system confederation [RFC5065]. A BGPsec speaker that
is not a member of such a confederation MUST set the Flags field of is not a member of such a confederation MUST NOT set the
the Secure_Path Segment to zero in all BGPsec update messages it Confed_Segment flag in its Secure_Path Segment (i.e. leave the flag
sends. bit at default value zero) in all BGPsec update messages it sends.
Section 4.4 contains instructions for reconstructing the AS_PATH Section 4.4 contains instructions for reconstructing the AS_PATH
attribute in cases where a BGPsec speaker receives an update message attribute in cases where a BGPsec speaker receives an update message
with a BGPsec_Path attribute and wishes to propagate the update with a BGPsec_Path attribute and wishes to propagate the update
message to a peer who does not support BGPsec. message to a peer who does not support BGPsec.
4.1. General Guidance 4.1. General Guidance
The information protected by the signature on a BGPsec update message The information protected by the signature on a BGPsec update message
includes the AS number of the peer to whom the update message is includes the AS number of the peer to whom the update message is
being sent. Therefore, if a BGPsec speaker wishes to send a BGPsec being sent. Therefore, if a BGPsec speaker wishes to send a BGPsec
update to multiple BGP peers, it must generate a separate BGPsec update to multiple BGP peers, it must generate a separate BGPsec
update message for each unique peer AS to whom the update message is update message for each unique peer AS to whom the update message is
sent. sent.
A BGPsec update message MUST advertise a route to only a single NLRI. A BGPsec update message MUST advertise a route to only a single
This is because a BGPsec speaker receiving an update message with prefix. This is because a BGPsec speaker receiving an update message
multiple NLRI would be unable to construct a valid BGPsec update with multiple prefixes would be unable to construct a valid BGPsec
message (i.e., valid path signatures) containing a subset of the NLRI update message (i.e., valid path signatures) containing a subset of
in the received update. If a BGPsec speaker wishes to advertise the prefixes in the received update. If a BGPsec speaker wishes to
routes to multiple NLRI, then it MUST generate a separate BGPsec advertise routes to multiple prefixes, then it MUST generate a
update message for each NLRI. Additionally, a BGPsec update message separate BGPsec update message for each prefix. Additionally, a
MUST use the MP_REACH_NLRI [RFC4760] attribute to encode the NLRI. BGPsec update message MUST use the MP_REACH_NLRI [RFC4760] attribute
to encode the prefix.
The BGPsec_Path attribute and the AS_PATH attribute are mutually The BGPsec_Path attribute and the AS_PATH attribute are mutually
exclusive. That is, any update message containing the BGPsec_Path exclusive. That is, any update message containing the BGPsec_Path
attribute MUST NOT contain the AS_PATH attribute. The information attribute MUST NOT contain the AS_PATH attribute. The information
that would be contained in the AS_PATH attribute is instead conveyed that would be contained in the AS_PATH attribute is instead conveyed
in the Secure_Path portion of the BGPsec_Path attribute. in the Secure_Path portion of the BGPsec_Path attribute.
In order to create or add a new signature to a BGPsec update message In order to create or add a new signature to a BGPsec update message
with a given algorithm suite, the BGPsec speaker must possess a with a given algorithm suite, the BGPsec speaker must possess a
private key suitable for generating signatures for this algorithm private key suitable for generating signatures for this algorithm
skipping to change at page 12, line 24 skipping to change at page 12, line 45
that prefix) to its external BGPsec-speaking peers.) that prefix) to its external BGPsec-speaking peers.)
Conversely, if a BGPsec router has received a BGPsec update message Conversely, if a BGPsec router has received a BGPsec update message
(with the BGPsec_Path attribute) from a peer for a given prefix and (with the BGPsec_Path attribute) from a peer for a given prefix and
it chooses to propagate that peer's route for the prefix, then it it chooses to propagate that peer's route for the prefix, then it
SHOULD propagate the route as a BGPsec update message containing the SHOULD propagate the route as a BGPsec update message containing the
BGPsec_Path attribute. BGPsec_Path attribute.
Note that removing BGPsec signatures (i.e., propagating a route Note that removing BGPsec signatures (i.e., propagating a route
advertisement without the BGPsec_Path attribute) has significant advertisement without the BGPsec_Path attribute) has significant
security ramifications. (See Section 7 for discussion of the security ramifications. (See Section 8 for discussion of the
security ramifications of removing BGPsec signatures.) Therefore, security ramifications of removing BGPsec signatures.) Therefore,
when a route advertisement is received via a BGPsec update message, when a route advertisement is received via a BGPsec update message,
propagating the route advertisement without the BGPsec_Path attribute propagating the route advertisement without the BGPsec_Path attribute
is NOT RECOMMENDED, unless the message is sent to a peer that did not is NOT RECOMMENDED, unless the message is sent to a peer that did not
advertise the capability to receive BGPsec update messages (see advertise the capability to receive BGPsec update messages (see
Section 4.4). Section 4.4).
Furthermore, note that when a BGPsec speaker propagates a route Furthermore, note that when a BGPsec speaker propagates a route
advertisement with the BGPsec_Path attribute it is not attesting to advertisement with the BGPsec_Path attribute it is not attesting to
the validation state of the update message it received. (See the validation state of the update message it received. (See
Section 7 for more discussion of the security semantics of BGPsec Section 8 for more discussion of the security semantics of BGPsec
signatures.) signatures.)
If the BGPsec speaker is producing an update message which would, in If the BGPsec speaker is producing an update message which would, in
the absence of BGPsec, contain an AS_SET (e.g., the BGPsec speaker is the absence of BGPsec, contain an AS_SET (e.g., the BGPsec speaker is
performing proxy aggregation), then the BGPsec speaker MUST NOT performing proxy aggregation), then the BGPsec speaker MUST NOT
include the BGPsec_Path attribute. In such a case, the BGPsec include the BGPsec_Path attribute. In such a case, the BGPsec
speaker must remove any existing BGPsec_Path in the received speaker must remove any existing BGPsec_Path in the received
advertisement(s) for this prefix and produce a traditional (non- advertisement(s) for this prefix and produce a traditional (non-
BGPsec) update message. It should be noted that BCP 172 [RFC6472] BGPsec) update message. It should be noted that BCP 172 [RFC6472]
recommends against the use of AS_SET and AS_CONFED_SET in the AS_PATH recommends against the use of AS_SET and AS_CONFED_SET in the AS_PATH
of BGP updates. of BGP updates.
The case where the BGPsec speaker sends a BGPsec update message to an The case where the BGPsec speaker sends a BGPsec update message to an
internal (iBGP) peer is quite simple. When originating a new route internal (iBGP) peer is quite simple. When originating a new route
advertisement and sending it to an internal peer, the BGPsec speaker advertisement and sending it to an internal peer, the BGPsec speaker
omits the BGPsec_Path attribute. When propagating a received route omits the BGPsec_Path attribute. When a BGPsec speaker chooses to
advertisement to an internal peer, the BGPsec speaker typically forward a BGPsec update message to an iBGP peer, the BGPsec_Path
populates the BGPsec_Path attribute by copying the BGPsec_Path attribute SHOULD NOT be removed, unless the peer doesn't support
attribute from the received update message. That is, the BGPsec_Path BGPsec. In the case when an iBGP peer doesn't support BGPsec, then
attribute is copied verbatim. However, in the case that the BGPsec the BGPsec update is reconstructed to a BGP update with AS_PATH and
speaker is performing an AS Migration, the BGPsec speaker may add an then forwarded (see Section 4.4). In particular, when forwarding to
additional signature on ingress before copying the BGPsec_Path a BGPsec capable iBGP peer, the BGPsec_Path attribute SHOULD NOT be
attribute (see [I-D.ietf-sidr-as-migration] for more details). Note removed even in the case where the BGPsec update message has not been
that when a BGPsec speaker chooses to forward a BGPsec update message successfully validated. (See Section 5 for more information on
to an iBGP peer, the BGPsec attribute SHOULD NOT be removed, unless validation, and Section 8 for the security ramifications of removing
the peer doesn't support BGPsec. In particular, the BGPsec attribute BGPsec signatures.)
SHOULD NOT be removed even in the case where the BGPsec update
message has not been successfully validated. (See Section 5 for more
information on validation, and Section 7 for the security
ramifications of removing BGPsec signatures.)
4.2. Constructing the BGPsec_Path Attribute 4.2. Constructing the BGPsec_Path Attribute
When a BGPsec speaker receives a BGPsec update message containing a When a BGPsec speaker receives a BGPsec update message containing a
BGPsec_Path attribute (with one or more signatures) from an (internal BGPsec_Path attribute (with one or more signatures) from an (internal
or external) peer, it may choose to propagate the route advertisement or external) peer, it may choose to propagate the route advertisement
by sending it to its other (internal or external) peers. When by sending it to its other (internal or external) peers. When
sending said route advertisement to an internal BGPsec-speaking peer, sending said route advertisement to an internal BGPsec-speaking peer,
the BGPsec_Path attribute SHALL NOT be modified. When sending said the BGPsec_Path attribute SHALL NOT be modified. When sending said
route advertisement to an external BGPsec-speaking peer, the route advertisement to an external BGPsec-speaking peer, the
skipping to change at page 13, line 38 skipping to change at page 14, line 8
attribute. attribute.
To generate the BGPsec_Path attribute on the outgoing update message, To generate the BGPsec_Path attribute on the outgoing update message,
the BGPsec speaker first generates a new Secure_Path Segment. Note the BGPsec speaker first generates a new Secure_Path Segment. Note
that if the BGPsec speaker is not the origin AS and there is an that if the BGPsec speaker is not the origin AS and there is an
existing BGPsec_Path attribute, then the BGPsec speaker prepends its existing BGPsec_Path attribute, then the BGPsec speaker prepends its
new Secure_Path Segment (places in first position) onto the existing new Secure_Path Segment (places in first position) onto the existing
Secure_Path. Secure_Path.
The AS number in this Secure_Path segment MUST match the AS number in The AS number in this Secure_Path segment MUST match the AS number in
the AS number resource extension field of the Resource PKI router the Subject field of the Resource PKI router certificate that will be
certificate(s) that will be used to verify the digital signature(s) used to verify the digital signature constructed by this BGPsec
constructed by this BGPsec speaker speaker (see Section 3.1.1.1 in [I-D.ietf-sidr-bgpsec-pki-profiles]
[I-D.ietf-sidr-bgpsec-pki-profiles]. and RFC 6487 [RFC6487]).
The pCount field of the Secure_Path Segment is typically set to the The pCount field of the Secure_Path Segment is typically set to the
value 1. However, a BGPsec speaker may set the pCount field to a value 1. However, a BGPsec speaker may set the pCount field to a
value greater than 1. Setting the pCount field to a value greater value greater than 1. Setting the pCount field to a value greater
than one has the same semantics as repeating an AS number multiple than one has the same semantics as repeating an AS number multiple
times in the AS_PATH of a non-BGPsec update message (e.g., for times in the AS_PATH of a non-BGPsec update message (e.g., for
traffic engineering purposes). traffic engineering purposes).
To prevent unnecessary processing load in the validation of BGPsec To prevent unnecessary processing load in the validation of BGPsec
signatures, a BGPsec speaker SHOULD NOT produce multiple consecutive signatures, a BGPsec speaker SHOULD NOT produce multiple consecutive
Secure_Path Segments with the same AS number. This means that to Secure_Path Segments with the same AS number. This means that to
achieve the semantics of prepending the same AS number k times, a achieve the semantics of prepending the same AS number k times, a
BGPsec speaker SHOULD produce a single Secure_Path Segment -- with BGPsec speaker SHOULD produce a single Secure_Path Segment -- with
pCount of k -- and a single corresponding Signature Segment. pCount of k -- and a single corresponding Signature Segment.
A route server that participates in the BGP control plane, but does A route server that participates in the BGP control plane, but does
not act as a transit AS in the data plane, may choose to set pCount not act as a transit AS in the data plane, may choose to set pCount
to 0. This option enables the route server to participate in BGPsec to 0. This option enables the route server to participate in BGPsec
and obtain the associated security guarantees without increasing the and obtain the associated security guarantees without increasing the
effective length of the AS path. (Note that BGPsec speakers compute length of the AS path. (Note that BGPsec speakers compute the length
the effective length of the AS path by summing the pCount values in of the AS path by summing the pCount values in the BGPsec_Path
the BGPsec_Path attribute, see Section 5.) However, when a route attribute, see Section 5.) However, when a route server sets the
server sets the pCount value to 0, it still inserts its AS number pCount value to 0, it still inserts its AS number into the
into the Secure_Path segment, as this information is needed to Secure_Path segment, as this information is needed to validate the
validate the signature added by the route server. (See signature added by the route server. (See
[I-D.ietf-sidr-as-migration] for a discussion of setting pCount to 0 [I-D.ietf-sidr-as-migration] for a discussion of setting pCount to 0
to facilitate AS Number Migration.) BGPsec speakers SHOULD drop to facilitate AS Number Migration.) BGPsec speakers SHOULD drop
incoming update messages with pCount set to zero in cases where the incoming update messages with pCount set to zero in cases where the
BGPsec speaker does not expect its peer to set pCount to zero. (That BGPsec speaker does not expect its peer to set pCount to zero. (That
is, pCount is only to be set to zero in cases such as route servers is, pCount is only to be set to zero in cases such as route servers
or AS Number Migration where the BGPsec speaker's peer expects pCount or AS Number Migration where the BGPsec speaker's peer expects pCount
to be set to zero.) to be set to zero.)
Next, the BGPsec speaker generates one or two Signature_Blocks. Next, the BGPsec speaker generates one or two Signature_Blocks.
Typically, a BGPsec speaker will use only a single algorithm suite, Typically, a BGPsec speaker will use only a single algorithm suite,
and thus create only a single Signature_Block in the BGPsec_Path and thus create only a single Signature_Block in the BGPsec_Path
attribute. However, to ensure backwards compatibility during a attribute. However, to ensure backwards compatibility during a
period of transition from a 'current' algorithm suite to a 'new' period of transition from a 'current' algorithm suite to a 'new'
algorithm suite, it will be necessary to originate update messages algorithm suite, it will be necessary to originate update messages
that contain a Signature_Block for both the 'current' and the 'new' that contain a Signature_Block for both the 'current' and the 'new'
algorithm suites (see Section 6.1). algorithm suites (see Section 6.1).
If the received BGPsec update message contains two Signature_Blocks If the received BGPsec update message contains two Signature_Blocks
and the BGPsec speaker supports both of the corresponding algorithm and the BGPsec speaker supports both of the corresponding algorithm
suites, then the new update message generated by the BGPsec speaker suites, then the new update message generated by the BGPsec speaker
SHOULD include both of the Signature_Blocks. If the received BGPsec MUST include both of the Signature_Blocks. If the received BGPsec
update message contains two Signature_Blocks and the BGPsec speaker update message contains two Signature_Blocks and the BGPsec speaker
only supports one of the two corresponding algorithm suites, then the only supports one of the two corresponding algorithm suites, then the
BGPsec speaker MUST remove the Signature_Block corresponding to the BGPsec speaker MUST remove the Signature_Block corresponding to the
algorithm suite that it does not understand. If the BGPsec speaker algorithm suite that it does not understand. If the BGPsec speaker
does not support the algorithm suites in any of the Signature_Blocks does not support the algorithm suites in any of the Signature_Blocks
contained in the received update message, then the BGPsec speaker contained in the received update message, then the BGPsec speaker
MUST NOT propagate the route advertisement with the BGPsec_Path MUST NOT propagate the route advertisement with the BGPsec_Path
attribute. (That is, if it chooses to propagate this route attribute. (That is, if it chooses to propagate this route
advertisement at all, it must do so as an unsigned BGP update advertisement at all, it must do so as an unsigned BGP update
message. See Section 4.4 for more information on converting to an message. See Section 4.4 for more information on converting to an
skipping to change at page 15, line 4 skipping to change at page 15, line 22
only supports one of the two corresponding algorithm suites, then the only supports one of the two corresponding algorithm suites, then the
BGPsec speaker MUST remove the Signature_Block corresponding to the BGPsec speaker MUST remove the Signature_Block corresponding to the
algorithm suite that it does not understand. If the BGPsec speaker algorithm suite that it does not understand. If the BGPsec speaker
does not support the algorithm suites in any of the Signature_Blocks does not support the algorithm suites in any of the Signature_Blocks
contained in the received update message, then the BGPsec speaker contained in the received update message, then the BGPsec speaker
MUST NOT propagate the route advertisement with the BGPsec_Path MUST NOT propagate the route advertisement with the BGPsec_Path
attribute. (That is, if it chooses to propagate this route attribute. (That is, if it chooses to propagate this route
advertisement at all, it must do so as an unsigned BGP update advertisement at all, it must do so as an unsigned BGP update
message. See Section 4.4 for more information on converting to an message. See Section 4.4 for more information on converting to an
unsigned BGP message.) unsigned BGP message.)
Note that in the case where the BGPsec_Path has two Signature_Blocks Note that in the case where the BGPsec_Path has two Signature_Blocks
(corresponding to different algorithm suites), the validation (corresponding to different algorithm suites), the validation
algorithm (see Section 5.2) deems a BGPsec update message to be algorithm (see Section 5.2) deems a BGPsec update message to be
'Valid' if there is at least one supported algorithm suite (and 'Valid' if there is at least one supported algorithm suite (and
corresponding Signature_Block) that is deemed 'Valid'. This means corresponding Signature_Block) that is deemed 'Valid'. This means
that a 'Valid' BGPsec update message may contain a Signature_Block that a 'Valid' BGPsec update message may contain a Signature_Block
which is not deemed 'Valid' (e.g., contains signatures that BGPsec which is not deemed 'Valid' (e.g., contains signatures that BGPsec
does not successfully verify). Nonetheless, such Signature_Blocks does not successfully verify). Nonetheless, such Signature_Blocks
MUST NOT be removed. (See Section 7 for a discussion of the security MUST NOT be removed. (See Section 8 for a discussion of the security
ramifications of this design choice.) ramifications of this design choice.)
For each Signature_Block corresponding to an algorithm suite that the For each Signature_Block corresponding to an algorithm suite that the
BGPsec speaker does support, the BGPsec speaker adds a new Signature BGPsec speaker does support, the BGPsec speaker SHOULD add a new
Segment to the Signature_Block. This Signature Segment is prepended Signature Segment to the Signature_Block. This Signature Segment is
to the list of Signature Segments (placed in the first position) so prepended to the list of Signature Segments (placed in the first
that the list of Signature Segments appear in the same order as the position) so that the list of Signature Segments appears in the same
corresponding Secure_Path segments. The BGPsec speaker populates the order as the corresponding Secure_Path segments. The BGPsec speaker
fields of this new signature segment as follows. populates the fields of this new signature segment as follows.
The Subject Key Identifier field in the new segment is populated with The Subject Key Identifier field in the new segment is populated with
the identifier contained in the Subject Key Identifier extension of the identifier contained in the Subject Key Identifier extension of
the RPKI router certificate corresponding to the BGPsec speaker the RPKI router certificate corresponding to the BGPsec speaker
[I-D.ietf-sidr-bgpsec-pki-profiles]. This Subject Key Identifier [I-D.ietf-sidr-bgpsec-pki-profiles]. This Subject Key Identifier
will be used by recipients of the route advertisement to identify the will be used by recipients of the route advertisement to identify the
proper certificate to use in verifying the signature. proper certificate to use in verifying the signature.
The Signature field in the new segment contains a digital signature The Signature field in the new segment contains a digital signature
that binds the NLRI and BGPsec_Path attribute to the RPKI router that binds the prefix and BGPsec_Path attribute to the RPKI router
certificate corresponding to the BGPsec speaker. The digital certificate corresponding to the BGPsec speaker. The digital
signature is computed as follows: signature is computed as follows:
o For clarity, let us number the Secure_Path and corresponding o For clarity, let us number the Secure_Path and corresponding
Signature Segments from 1 to N as follows. Let Secure_Path Signature Segments from 1 to N as follows. Let Secure_Path
Segment 1 and Signature Segment 1 be the segments produced by the Segment 1 and Signature Segment 1 be the segments produced by the
origin AS. Let Secure_Path Segment 2 and Signature Segment 2 be origin AS. Let Secure_Path Segment 2 and Signature Segment 2 be
the segments added by the next AS after the origin. Continue this the segments added by the next AS after the origin. Continue this
method of numbering and ultimately let Secure_Path Segment N be method of numbering and ultimately let Secure_Path Segment N and
the Secure_Path segment that is being added by the current AS. Signature Segment N be those that are being added by the current
AS. The current AS (Nth AS) is signing and forwarding the update
to the next AS (i.e. (N+1)th AS) in the chain of ASes that form
the AS path.
o In order to construct the digital signature for Signature Segment o In order to construct the digital signature for Signature Segment
N (the signature segment being produced by the current AS), first N (the signature segment being produced by the current AS), first
construct the following sequence of octets to be hashed. construct the sequence of octets to be hashed as shown in
Figure 8. (Note: This sequence of octets includes all the data
that the Nth AS attests to by adding its digital signature in the
update which is being forwarded to a BGPsec speaker in the (N+1)th
AS.)
Sequence of Octets to be Hashed +------------------------------------+
| Target AS Number |
+------------------------------------+ ---\
| Signature Segment : N-1 | \
+------------------------------------+ |
| Secure_Path Segment : N | |
+------------------------------------+ \
... > Data from
+------------------------------------+ / N Segments
| Signature Segment : 1 | |
+------------------------------------+ |
| Secure_Path Segment : 2 | |
+------------------------------------+ /
| Secure_Path Segment : 1 | /
+------------------------------------+---/
| Algorithm Suite Identifier |
+------------------------------------+
| AFI |
+------------------------------------+
| SAFI |
+------------------------------------+
| Prefix |
+------------------------------------+
+------------------------------------+ Figure 8: Sequence of octets to be hashed.
| Target AS Number |
+------------------------------------+ -\
| Signature Segment : N-1 | \
+------------------------------------+ |
| Secure_Path Segment : N | |
+------------------------------------+ \
... > For N Hops
+------------------------------------+ /
| Signature Segment : 1 | |
+------------------------------------+ |
| Secure_Path Segment : 2 | /
+------------------------------------+ -/
| Secure_Path Segment : 1 |
+------------------------------------+
| Algorithm Suite Identifier |
+------------------------------------+
| AFI |
+------------------------------------+
| SAFI |
+------------------------------------+
| NLRI |
+------------------------------------+
In this sequence, the Target AS Number is the AS to whom the The elements in this sequence (Figure 8) MUST be ordered exactly
BGPsec speaker intends to send the update message. (Note that the as shown. The 'Target AS Number' is the AS to whom the BGPsec
Target AS number is the AS number announced by the peer in the speaker intends to send the update message. (Note that the
'Target AS Number' is the AS number announced by the peer in the
OPEN message of the BGP session within which the update is sent.) OPEN message of the BGP session within which the update is sent.)
The Secure_Path and Signature Segments (1 through N-1) are The Secure_Path and Signature Segments (1 through N-1) are
obtained from the BGPsec_Path attribute. Finally, the Address obtained from the BGPsec_Path attribute. Finally, the Address
Family Identifier (AFI), Subsequent Address Family Identifier Family Identifier (AFI), Subsequent Address Family Identifier
(SAFI), and Network Layer Reachability Information (NLRI) fields (SAFI), and Prefix fields are obtained from the MP_REACH_NLRI
are obtained from the MP_REACH_NLRI attribute. Additionally, in attribute. Additionally, in the Prefix field all of the trailing
the Prefix field of the NLRI (from MP_REACH_NLRI), all of the bits MUST be set to zero when constructing this sequence.
trailing bits MUST be set to zero when constructing this sequence.
o Apply to this octet sequence the digest algorithm (for the o Apply to this octet sequence (in Figure 8) the digest algorithm
algorithm suite of this Signature_Block) to obtain a digest value. (for the algorithm suite of this Signature_Block) to obtain a
digest value.
o Apply to this digest value the signature algorithm, (for the o Apply to this digest value the signature algorithm, (for the
algorithm suite of this Signature_Block) to obtain the digital algorithm suite of this Signature_Block) to obtain the digital
signature. Then populate the Signature Field with this digital signature. Then populate the Signature Field (in Figure 7) with
signature. this digital signature.
The Signature Length field is populated with the length (in octets) The Signature Length field (in Figure 7) is populated with the length
of the value in the Signature field. (in octets) of the value in the Signature field.
4.3. Processing Instructions for Confederation Members 4.3. Processing Instructions for Confederation Members
Members of autonomous system confederations [RFC5065] MUST Members of autonomous system confederations [RFC5065] MUST
additionally follow the instructions in this section for processing additionally follow the instructions in this section for processing
BGPsec update messages. BGPsec update messages.
When a confederation member sends a BGPsec update message to a peer When a confederation member sends a BGPsec update message to a peer
that is a member of the same Member-AS, the confederation member that is a member of the same Member-AS, the confederation member
SHALL NOT modify the BGPsec_Path attribute. When a confederation SHALL NOT modify the BGPsec_Path attribute. When a confederation
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confederation) as well as a corresponding Signature Segment. Note confederation) as well as a corresponding Signature Segment. Note
that all fields other that the AS field are populated as per that all fields other that the AS field are populated as per
Section 4.2. Section 4.2.
When validating a received BGPsec update message, confederation When validating a received BGPsec update message, confederation
members need to make the following adjustment to the algorithm members need to make the following adjustment to the algorithm
presented in Section 5.2. When a confederation member processes presented in Section 5.2. When a confederation member processes
(validates) a Signature Segment and its corresponding Secure_Path (validates) a Signature Segment and its corresponding Secure_Path
Segment, the confederation member must note the following. For a Segment, the confederation member must note the following. For a
signature produced by a peer BGPsec speaker outside of a signature produced by a peer BGPsec speaker outside of a
confederation, the Target AS will always be the AS Confederation confederation, the 'Target AS Number' will always be the AS
Identifier (the public AS number of the confederation) as opposed to Confederation Identifier (the public AS number of the confederation)
the Member-AS Number. as opposed to the Member-AS Number.
To handle this case, when a BGPsec speaker (that is a confederation To handle this case, when a BGPsec speaker (that is a confederation
member) processes a current Secure_Path Segment that has the member) processes a current Secure_Path Segment that has the
Confed_Segment flag set to zero, if the next most recently added Confed_Segment flag set to zero, if the next most recently added
Secure_Path segment has the Confed_Segment flag set to one then, when Secure_Path segment has the Confed_Segment flag set to one then, when
computing the digest for the current Secure_Path segment, the BGPsec computing the digest for the current Secure_Path segment, the BGPsec
speaker takes the Target AS Number to be the AS Confederation speaker takes the 'Target AS Number' to be the AS Confederation
Identifier of the validating BGPsec speaker's own confederation. Identifier of the validating BGPsec speaker's own confederation.
(Note that the algorithm in Section 5.2 processes Secure_Path (Note that the algorithm in Section 5.2 processes Secure_Path
Segments in order from most recently added to least recently added, Segments in order from most recently added to least recently added,
therefore this special case will apply to the first Secure_Path therefore, this special case will apply to the first Secure_Path
segment that the algorithm encounters that has the Confed_Segment segment that the algorithm encounters that has the Confed_Segment
flag set to zero.) flag set to zero.)
Finally, as discussed above, an AS confederation may optionally Finally, as discussed above, an AS confederation may optionally
decide that its members will not verify digital signatures added by decide that its members will not verify digital signatures added by
members. In such a federation, when a confederation member runs the members. In such a federation, when a confederation member runs the
algorithm in Section 5.2, the confederation member, during processing algorithm in Section 5.2, the confederation member, during the
of a Signature Segment, first checks whether the Confed_Sequence flag process of error checking, first checks whether the Confed_Segment
in the corresponding Secure_Path segment is set to one. If the flag in the corresponding Secure_Path segment is set to one. If the
Confed_Sequence flag is set to one in the corresponding Secure_Path Confed_Segment flag is set to one in the corresponding Secure_Path
segment, the confederation member does not perform any further checks segment, the confederation member does not perform any further checks
on the Signature Segment and immediately moves on to the next on the Signature Segment and immediately moves on to the next
Signature Segment (and checks its corresponding Secure_Path segment). Signature Segment (and checks its corresponding Secure_Path segment).
Note that as specified in Section 5.2, it is an error when a BGPsec Note that as specified in Section 5.2, it is an error when a BGPsec
speaker receives from a peer, who is not in the same AS speaker receives from a peer, who is not in the same AS
confederation, a BGPsec update containing a Confed_Sequence flag set confederation, a BGPsec update containing a Confed_Segment flag set
to one. (As discussed in Section 5.2, any error in the BGPsec_Path to one. As discussed in Section 5.2, any syntactical or protocol
attribute MUST be handled using the "treat-as-withdraw", approach as violation errors in the BGPsec_Path attribute MUST be handled using
defined in RFC 7606 [RFC7606].) the "treat-as-withdraw" approach as defined in RFC 7606 [RFC7606].
4.4. Reconstructing the AS_PATH Attribute 4.4. Reconstructing the AS_PATH Attribute
BGPsec update messages do not contain the AS_PATH attribute. BGPsec update messages do not contain the AS_PATH attribute.
However, the AS_PATH attribute can be reconstructed from the However, the AS_PATH attribute can be reconstructed from the
BGPsec_Path attribute. This is necessary in the case where a route BGPsec_Path attribute. This is necessary in the case where a route
advertisement is received via a BGPsec update message and then advertisement is received via a BGPsec update message and then
propagated to a peer via a non-BGPsec update message (e.g., because propagated to a peer via a non-BGPsec update message (e.g., because
the latter peer does not support BGPsec). Note that there may be the latter peer does not support BGPsec). Note that there may be
additional cases where an implementation finds it useful to perform additional cases where an implementation finds it useful to perform
skipping to change at page 21, line 27 skipping to change at page 22, line 7
[I-D.ietf-sidr-rpki-rtr-rfc6810-bis]), the BGPsec speaker MUST re-run [I-D.ietf-sidr-rpki-rtr-rfc6810-bis]), the BGPsec speaker MUST re-run
validation on all affected update messages stored in its Adj-RIB-In. validation on all affected update messages stored in its Adj-RIB-In.
For example, when a given RPKI certificate ceases to be valid (e.g., For example, when a given RPKI certificate ceases to be valid (e.g.,
it expires or is revoked), all update messages containing a signature it expires or is revoked), all update messages containing a signature
whose SKI matches the SKI in the given certificate must be re- whose SKI matches the SKI in the given certificate must be re-
assessed to determine if they are still valid. If this reassessment assessed to determine if they are still valid. If this reassessment
determines that the validity state of an update has changed then, determines that the validity state of an update has changed then,
depending on local policy, it may be necessary to re-run best path depending on local policy, it may be necessary to re-run best path
selection. selection.
BGPsec update messages do not contain an AS_PATH attribute. BGPsec update messages do not contain an AS_PATH attribute. The
Therefore, a BGPsec speaker MUST utilize the AS path information in Secure_Path contains AS path information for the BGPsec update
the BGPsec_Path attribute in all cases where it would otherwise use message. Therefore, a BGPsec speaker MUST utilize the AS path
the AS path information in the AS_PATH attribute. The only exception information in the Secure_Path in all cases where it would otherwise
to this rule is when AS path information must be updated in order to use the AS path information in the AS_PATH attribute. The only
propagate a route to a peer (in which case the BGPsec speaker follows exception to this rule is when AS path information must be updated in
the instructions in Section 4). Section 4.4 provides an algorithm order to propagate a route to a peer (in which case the BGPsec
for constructing an AS_PATH attribute from a BGPsec_Path attribute. speaker follows the instructions in Section 4). Section 4.4 provides
Whenever the use of AS path information is called for (e.g., loop an algorithm for constructing an AS_PATH attribute from a BGPsec_Path
detection, or use of AS path length in best path selection) the attribute. Whenever the use of AS path information is called for
externally visible behavior of the implementation shall be the same (e.g., loop detection, or use of AS path length in best path
as if the implementation had run the algorithm in Section 4.4 and selection) the externally visible behavior of the implementation
used the resulting AS_PATH attribute as it would for a non-BGPsec shall be the same as if the implementation had run the algorithm in
update message. Section 4.4 and used the resulting AS_PATH attribute as it would for
a non-BGPsec update message.
Many signature algorithms are non-deterministic. That is, many Many signature algorithms are non-deterministic. That is, many
signature algorithms will produce different signatures each time they signature algorithms will produce different signatures each time they
are run (even when they are signing the same data with the same key). are run (even when they are signing the same data with the same key).
Therefore, if an implementation receives a BGPsec update from a peer Therefore, if an implementation receives a BGPsec update from a peer
and later receives a second BGPsec update message from the same peer, and later receives a second BGPsec update message from the same peer,
the implementation SHOULD treat the second message as a duplicate the implementation SHOULD treat the second message as a duplicate
update message if it differs from the first update message only in update message if it differs from the first update message only in
the Signature fields (within the BGPsec_Path attribute). That is, if the Signature fields (within the BGPsec_Path attribute). That is, if
all the fields in the second update are identical to the fields in all the fields in the second update are identical to the fields in
the first update message, except for the Signature fields, then the the first update message, except for the Signature fields, then the
second update message should be treated as a duplicate of the first second update message should be treated as a duplicate of the first
update message. Note that if other fields (e.g., the Subject Key update message. Note that if other fields (e.g., the Subject Key
Identifier field) within a Signature segment differ between two Identifier field) within a Signature segment differ between two
update messages then the two updates are not duplicates. update messages then the two updates are not duplicates.
With regards to the processing of duplicate update messages, if the With regards to the processing of duplicate update messages, if the
first update message is valid, then an implementation SHOULD NOT run first update message is valid, then an implementation SHOULD NOT run
the validation procedure on the second, duplicate update message the validation procedure on the duplicate update message (even if the
(even if the bits of the signature field are different). If the bits of the signature field are different). If the first update
first update message is not valid, then an implementation SHOULD run message is not valid, then an implementation SHOULD run the
the validation procedure on the second duplicate update message (as validation procedure on the second duplicate update message (as the
the signatures in the second update may be valid even though the signatures in the second update may be valid even though the first
first contained a signature that was invalid). contained a signature that was invalid). Please see additional notes
in Section 7.
5.1. Overview of BGPsec Validation 5.1. Overview of BGPsec Validation
Validation of a BGPsec update messages makes use of data from RPKI Validation of a BGPsec update messages makes use of data from RPKI
certificates. In particular, it is necessary that the recipient have certificates. In particular, it is necessary that the recipient have
access to the following data obtained from valid RPKI certificates: access to the following data obtained from valid RPKI certificates:
the AS Number, Public Key and Subject Key Identifier from each valid the AS Number, Public Key and Subject Key Identifier from each valid
RPKI router certificate. RPKI router certificate.
Note that the BGPsec speaker could perform the validation of RPKI Note that the BGPsec speaker could perform the validation of RPKI
certificates on its own and extract the required data, or it could certificates on its own and extract the required data, or it could
receive the same data from a trusted cache that performs RPKI receive the same data from a trusted cache that performs RPKI
validation on behalf of (some set of) BGPsec speakers. (For example, validation on behalf of (some set of) BGPsec speakers. (For example,
the trusted cache could deliver the necessary validity information to the trusted cache could deliver the necessary validity information to
the BGPsec speaker using the router key PDU the BGPsec speaker using the router key PDU for the RPKI-to-Router
[I-D.ietf-sidr-rtr-keying] for the RPKI-to-Router protocol protocol [I-D.ietf-sidr-rpki-rtr-rfc6810-bis].)
[I-D.ietf-sidr-rpki-rtr-rfc6810-bis].)
To validate a BGPsec update message containing the BGPsec_Path To validate a BGPsec update message containing the BGPsec_Path
attribute, the recipient performs the validation steps specified in attribute, the recipient performs the validation steps specified in
Section 5.2. The validation procedure results in one of two states: Section 5.2. The validation procedure results in one of two states:
'Valid' and 'Not Valid'. 'Valid' and 'Not Valid'.
It is expected that the output of the validation procedure will be It is expected that the output of the validation procedure will be
used as an input to BGP route selection. That said, BGP route used as an input to BGP route selection. That said, BGP route
selection, and thus the handling of the validation states is a matter selection, and thus the handling of the validation states is a matter
of local policy, and is handled using local policy mechanisms. of local policy, and is handled using local policy mechanisms.
Implementations SHOULD enable operators to set such local policy on a Implementations SHOULD enable operators to set such local policy on a
per-session basis. (That is, we expect some operators will choose to per-session basis. (That is, it is expected that some operators will
treat BGPsec validation status differently for update messages choose to treat BGPsec validation status differently for update
received over different BGP sessions.) messages received over different BGP sessions.)
It is expected that BGP peers will generally prefer routes received It is expected that BGP peers will generally prefer routes received
via 'Valid' BGPsec update messages over both routes received via 'Not via 'Valid' BGPsec update messages over both routes received via 'Not
Valid' BGPsec update messages and routes received via update messages Valid' BGPsec update messages and routes received via update messages
that do not contain the BGPsec_Path attribute. However, BGPsec that do not contain the BGPsec_Path attribute. (See
specifies no changes to the BGP decision process. (See
[I-D.ietf-sidr-bgpsec-ops] for related operational considerations.) [I-D.ietf-sidr-bgpsec-ops] for related operational considerations.)
BGPsec validation needs only be performed at the eBGP edge. The BGPsec validation needs only be performed at the eBGP edge. The
validation status of a BGP signed/unsigned update MAY be conveyed via validation status of a BGP signed/unsigned update MAY be conveyed via
iBGP from an ingress edge router to an egress edge router via some iBGP from an ingress edge router to an egress edge router via some
mechanism, according to local policy within an AS. As discussed in mechanism, according to local policy within an AS. As discussed in
Section 4, when a BGPsec speaker chooses to forward a (syntactically Section 4, when a BGPsec speaker chooses to forward a (syntactically
correct) BGPsec update message, it SHOULD be forwarded with its correct) BGPsec update message, it should be forwarded with its
BGPsec_Path attribute intact (regardless of the validation state of BGPsec_Path attribute intact (regardless of the validation state of
the update message). Based entirely on local policy, an egress the update message). Based entirely on local policy, an egress
router receiving a BGPsec update message from within its own AS MAY router receiving a BGPsec update message from within its own AS MAY
choose to perform its own validation. choose to perform its own validation.
5.2. Validation Algorithm 5.2. Validation Algorithm
This section specifies an algorithm for validation of BGPsec update This section specifies an algorithm for validation of BGPsec update
messages. A conformant implementation MUST include a BGPsec update messages. A conformant implementation MUST include a BGPsec update
validation algorithm that is functionally equivalent to the validation algorithm that is functionally equivalent to the
externally visible behavior of this algorithm. externally visible behavior of this algorithm.
First, the recipient of a BGPsec update message performs a check to First, the recipient of a BGPsec update message performs a check to
ensure that the message is properly formed. Specifically, the ensure that the message is properly formed. Both syntactical and
recipient performs the following checks: protocol violation errors are checked. The error checks specified in
Section 6.3 of [RFC4271] are performed, except that for BGPsec
updates the checks on the AS_PATH attribute do not apply and instead
the following checks on BGPsec_Path attribute are performed:
1. Check to ensure that the entire BGPsec_Path attribute is 1. Check to ensure that the entire BGPsec_Path attribute is
syntactically correct (conforms to the specification in this syntactically correct (conforms to the specification in this
document). document).
2. Check that each Signature_Block contains one Signature segment 2. Check that AS number in the most recently added Secure_Path
segment (i.e. the one corresponding to the peer from which the
update message was received) matches the AS number of that peer
(as specified in the BGP OPEN message).
3. Check that each Signature_Block contains one Signature segment
for each Secure_Path segment in the Secure_Path portion of the for each Secure_Path segment in the Secure_Path portion of the
BGPsec_Path attribute. (Note that the entirety of each BGPsec_Path attribute. (Note that the entirety of each
Signature_Block must be checked to ensure that it is well formed, Signature_Block must be checked to ensure that it is well formed,
even though the validation process may terminate before all even though the validation process may terminate before all
signatures are cryptographically verified.) signatures are cryptographically verified.)
3. Check that the update message does not contain an AS_PATH 4. Check that the update message does not contain an AS_PATH
attribute. attribute.
4. If the update message was received from a peer that is not a 5. If the update message was received from an BGPsec peer that is
not a member of the BGPsec speaker's AS confederation, check to
ensure that none of the Secure_Path segments contain a Flags
field with the Confed_Segment flag set to one.
6. If the update message was received from a BGPsec peer that is a
member of the BGPsec speaker's AS confederation, check to ensure member of the BGPsec speaker's AS confederation, check to ensure
that none of the Secure_Path segments contain a Flags field with that the Secure_Path segment corresponding to that peer contains
the Confed_Sequence flag set to one. a Flags field with the Confed_Segment flag set to one.
5. If the update message was received from a peer that is not 7. If the update message was received from a peer that is not
expected to set pCount equal to zero (see Section 4.2) then check expected to set pCount equal to zero (see Section 4.2) then check
to ensure that the pCount field in the most-recently added to ensure that the pCount field in the most-recently added
Secure_Path segment is not equal to zero. Secure_Path segment is not equal to zero.
If any of these checks fail, it is an error in the BGPsec_Path If any of these checks fail, it is an error in the BGPsec_Path
attribute. Any of these errors in the BGPsec_Path attribute are attribute. Any of these errors in the BGPsec_Path attribute are
handled as per RFC 7606 [RFC7606]. BGPsec speakers MUST handle these handled as per RFC 7606 [RFC7606]. BGPsec speakers MUST handle these
errors using the "treat-as-withdraw" approach as defined in RFC 7606 errors using the "treat-as-withdraw" approach as defined in RFC 7606
[RFC7606]. [RFC7606].
Next, the BGPsec speaker examines the Signature_Blocks in the Next, the BGPsec speaker examines the Signature_Blocks in the
BGPsec_Path attribute. A Signature_Block corresponding to an BGPsec_Path attribute. A Signature_Block corresponding to an
algorithm suite that the BGPsec speaker does not support is not algorithm suite that the BGPsec speaker does not support is not
considered in validation. If there is no Signature_Block considered in validation. If there is no Signature_Block
corresponding to an algorithm suite that the BGPsec speaker supports, corresponding to an algorithm suite that the BGPsec speaker supports,
then the BGPsec speaker MUST treat the update message in the same then in order to consider the update in the route selection process,
manner that the BGPsec speaker would treat an (unsigned) update the BGPsec speaker MUST strip the Signature_Block(s), reconstruct the
message that arrived without a BGPsec_Path attribute. AS_PATH from the Secure_Path (see Section 4.4), and treat the update
as if it was received as an unsigned BGP update.
For each remaining Signature_Block (corresponding to an algorithm For each remaining Signature_Block (corresponding to an algorithm
suite supported by the BGPsec speaker), the BGPsec speaker iterates suite supported by the BGPsec speaker), the BGPsec speaker iterates
through the Signature segments in the Signature_Block, starting with through the Signature segments in the Signature_Block, starting with
the most recently added segment (and concluding with the least the most recently added segment (and concluding with the least
recently added segment). Note that there is a one-to-one recently added segment). Note that there is a one-to-one
correspondence between Signature segments and Secure_Path segments correspondence between Signature segments and Secure_Path segments
within the BGPsec_Path attribute. The following steps make use of within the BGPsec_Path attribute. The following steps make use of
this correspondence. this correspondence.
o (Step 0): For clarity, let us number the Secure_Path and o (Step 1): Let there be K AS hops in a received BGPsec_Path
corresponding Signature Segments from 1 to N as follows. Let attribute that is to be validated. Let AS(1), AS(2), ..., AS(K+1)
Secure_Path Segment 1 and Signature Segment 1 be the segments denote the sequence of AS numbers from the origin AS to the
produced by the origin AS. Let Secure_Path Segment 2 and validating AS. Let Secure_Path Segment N and Signature Segment N
Signature Segment 2 be the segments added by the next AS after the in the BGPsec_Path attribute refer to those corresponding to AS(N)
origin. Continue this method of numbering and ultimately let (where N = 1, 2, ..., K). The BGPsec speaker that is processing
and validating the BGPsec_Path attribute resides in AS(K+1). Let
Signature Segment N be the Signature Segment that is currently Signature Segment N be the Signature Segment that is currently
being verified and let Secure_Path Segment N be the corresponding being verified.
Secure_Path Segment.
o (Step I): Locate the public key needed to verify the signature (in o (Step 2): Locate the public key needed to verify the signature (in
the current Signature segment). To do this, consult the valid the current Signature segment). To do this, consult the valid
RPKI router certificate data and look up all valid (AS, SKI, RPKI router certificate data and look up all valid (AS, SKI,
Public Key) triples in which the AS matches the AS number in the Public Key) triples in which the AS matches the AS number in the
corresponding Secure_Path segment. Of these triples that match corresponding Secure_Path segment. Of these triples that match
the AS number, check whether there is an SKI that matches the the AS number, check whether there is an SKI that matches the
value in the Subject Key Identifier field of the Signature value in the Subject Key Identifier field of the Signature
segment. If this check finds no such matching SKI value, then segment. If this check finds no such matching SKI value, then
mark the entire Signature_Block as 'Not Valid' and proceed to the mark the entire Signature_Block as 'Not Valid' and proceed to the
next Signature_Block. next Signature_Block.
o (Step II): Compute the digest function (for the given algorithm o (Step 3): Compute the digest function (for the given algorithm
suite) on the appropriate data. suite) on the appropriate data.
In order to verify the digital signature in Signature Segment N, In order to verify the digital signature in Signature Segment N,
construct the following sequence of octets to be hashed. construct the sequence of octets to be hashed as shown in Figure 9
(using the notations defined in Step 1). (Note that this sequence
is the same sequence that was used by AS(N) that created the
Signature Segment N (see Section 4.2 and Figure 8).)
Sequence of Octets to be Hashed for Signature Verification +------------------------------------+
| Target AS Number |
+------------------------------------+ ---\
| Signature Segment : N-1 | \
+------------------------------------+ |
| Secure_Path Segment : N | |
+------------------------------------+ \
... > Data from
+------------------------------------+ / N Segments
| Signature Segment : 1 | |
+------------------------------------+ |
| Secure_Path Segment : 2 | |
+------------------------------------+ /
| Secure_Path Segment : 1 | /
+------------------------------------+---/
| Algorithm Suite Identifier |
+------------------------------------+
| AFI |
+------------------------------------+
| SAFI |
+------------------------------------+
| Prefix |
+------------------------------------+
+------------------------------------+ Figure 9: The Sequence of octets to be hashed for signature
| Target AS Number | verification of Signature Segment N; N = 1,2, ..., K, where K is the
+------------------------------------+ -\ number of AS hops in the BGPsec_Path attribute.
| Signature Segment : N-1 | \
+------------------------------------+ |
| Secure_Path Segment : N | |
+------------------------------------+ \
... > For N Hops
+------------------------------------+ /
| Signature Segment : 1 | |
+------------------------------------+ |
| Secure_Path Segment : 2 | /
+------------------------------------+ -/
| Secure_Path Segment : 1 |
+------------------------------------+
| Algorithm Suite Identifier |
+------------------------------------+
| AFI |
+------------------------------------+
| SAFI |
+------------------------------------+
| NLRI |
+------------------------------------+
For the first segment to be processed (the most recently added The elements in this sequence (Figure 9) MUST be ordered exactly
segment), the 'Target AS Number' is the AS number of the BGPsec as shown. For the first segment to be processed (the most
speaker validating the update message. Note that if a BGPsec recently added segment (i.e. N = K) given that there are K hops
speaker uses multiple AS Numbers (e.g., the BGPsec speaker is a in the Secure_Path), the 'Target AS Number' is AS(K+1), the AS
member of a confederation), the AS number used here MUST be the AS number of the BGPsec speaker validating the update message. Note
number announced in the OPEN message for the BGP session over that if a BGPsec speaker uses multiple AS Numbers (e.g., the
which the BGPsec update was received. BGPsec speaker is a member of a confederation), the AS number used
here MUST be the AS number announced in the OPEN message for the
BGP session over which the BGPsec update was received.
For each other Signature Segment, the 'Target AS Number' is the AS For each other Signature Segment (N smaller than K), the 'Target
number in the Secure_Path segment that corresponds to the AS Number' is AS(N+1), the AS number in the Secure_Path segment
Signature Segment added immediately after the one being processed. that corresponds to the Signature Segment added immediately after
(That is, in the Secure_Path segment that corresponds to the the one being processed. (That is, in the Secure_Path segment
Signature segment that the validator just finished processing.) that corresponds to the Signature segment that the validator just
finished processing.)
The Secure_Path and Signature Segment are obtained from the The Secure_Path and Signature Segment are obtained from the
BGPsec_Path attribute. The Address Family Identifier (AFI), BGPsec_Path attribute. The Address Family Identifier (AFI),
Subsequent Address Family Identifier (SAFI), and Network Layer Subsequent Address Family Identifier (SAFI), and Prefix fields are
Reachability Information (NLRI) fields are obtained from the obtained from the MP_REACH_NLRI attribute. Additionally, in the
MP_REACH_NLRI attribute. Additionally, in the Prefix field of the Prefix field all of the trailing bits MUST be set to zero when
NLRI (from MP_REACH_NLRI), all of the trailing bits MUST be set to constructing this sequence.
zero when constructing this sequence.
o (Step III): Use the signature validation algorithm (for the given o (Step 4): Use the signature validation algorithm (for the given
algorithm suite) to verify the signature in the current segment. algorithm suite) to verify the signature in the current segment.
That is, invoke the signature validation algorithm on the That is, invoke the signature validation algorithm on the
following three inputs: the value of the Signature field in the following three inputs: the value of the Signature field in the
current segment; the digest value computed in Step II above; and current segment; the digest value computed in Step 3 above; and
the public key obtained from the valid RPKI data in Step I above. the public key obtained from the valid RPKI data in Step 2 above.
If the signature validation algorithm determines that the If the signature validation algorithm determines that the
signature is invalid, then mark the entire Signature_Block as 'Not signature is invalid, then mark the entire Signature_Block as 'Not
Valid' and proceed to the next Signature_Block. If the signature Valid' and proceed to the next Signature_Block. If the signature
validation algorithm determines that the signature is valid, then validation algorithm determines that the signature is valid, then
continue processing Signature Segments (within the current continue processing Signature Segments (within the current
Signature_Block). Signature_Block).
If all Signature Segments within a Signature_Block pass validation If all Signature Segments within a Signature_Block pass validation
(i.e., all segments are processed and the Signature_Block has not yet (i.e., all segments are processed and the Signature_Block has not yet
been marked 'Not Valid'), then the Signature_Block is marked as been marked 'Not Valid'), then the Signature_Block is marked as
skipping to change at page 27, line 5 skipping to change at page 28, line 11
understood not only by the peer to whom it is directly sending the understood not only by the peer to whom it is directly sending the
message, but also by all BGPsec speakers to whom the route message, but also by all BGPsec speakers to whom the route
advertisement is eventually propagated. Therefore, selection of an advertisement is eventually propagated. Therefore, selection of an
algorithm suite cannot be a local matter negotiated by BGP peers, but algorithm suite cannot be a local matter negotiated by BGP peers, but
instead must be coordinated throughout the Internet. instead must be coordinated throughout the Internet.
To this end, a mandatory algorithm suites document exists which To this end, a mandatory algorithm suites document exists which
specifies a mandatory-to-use 'current' algorithm suite for use by all specifies a mandatory-to-use 'current' algorithm suite for use by all
BGPsec speakers [I-D.ietf-sidr-bgpsec-algs]. BGPsec speakers [I-D.ietf-sidr-bgpsec-algs].
We anticipate that, in the future, the mandatory algorithm suites It is anticipated that, in the future, the mandatory algorithm suites
document will be updated to specify a transition from the 'current' document will be updated to specify a transition from the 'current'
algorithm suite to a 'new' algorithm suite. During the period of algorithm suite to a 'new' algorithm suite. During the period of
transition (likely a small number of years), all BGPsec update transition (likely a small number of years), all BGPsec update
messages SHOULD simultaneously use both the 'current' algorithm suite messages SHOULD simultaneously use both the 'current' algorithm suite
and the 'new' algorithm suite. (Note that Section 3 and Section 4 and the 'new' algorithm suite. (Note that Section 3 and Section 4
specify how the BGPsec_Path attribute can contain signatures, in specify how the BGPsec_Path attribute can contain signatures, in
parallel, for two algorithm suites.) Once the transition is parallel, for two algorithm suites.) Once the transition is
complete, use of the old 'current' algorithm will be deprecated, use complete, use of the old 'current' algorithm will be deprecated, use
of the 'new' algorithm will be mandatory, and a subsequent 'even of the 'new' algorithm will be mandatory, and a subsequent 'even
newer' algorithm suite may be specified as recommended to implement. newer' algorithm suite may be specified as recommended to implement.
skipping to change at page 28, line 7 skipping to change at page 29, line 15
At this point a transition would begin which is analogous to the At this point a transition would begin which is analogous to the
algorithm transition discussed in Section 6.1. During the transition algorithm transition discussed in Section 6.1. During the transition
period all BGPsec speakers should simultaneously include both the period all BGPsec speakers should simultaneously include both the
BGPsec_Path attribute and the new BGPsec_Path_Two attribute. Once BGPsec_Path attribute and the new BGPsec_Path_Two attribute. Once
the transition is complete, the use of BGPsec_Path could then be the transition is complete, the use of BGPsec_Path could then be
deprecated, at which point BGPsec speakers should include only the deprecated, at which point BGPsec speakers should include only the
new BGPsec_Path_Two attribute. Such a process could facilitate a new BGPsec_Path_Two attribute. Such a process could facilitate a
transition to a new BGPsec semantics in a backwards compatible transition to a new BGPsec semantics in a backwards compatible
fashion. fashion.
7. Security Considerations 7. Operations and Management Considerations
Some operations and management issues that are closely relevant to
BGPsec protocol specification and its deployment are highlighted
here. Detailed recommendations concerning operations and management
issues with BGPsec are provided in [I-D.ietf-sidr-bgpsec-ops].
This document specifies BGPsec Version 0 only. What should the
action be if the Version is not 0 in the BGPsec capability
advertisement from a peer? If the intersection of BGPsec capability
advertisements from both sides does not include Version 0, then
BGPsec Version 0 has not been successfully negotiated. However, a
BGP session is still negotiated and hence the ability to exchange
routes is still there. BGP (unsigned) messages are exchanged. So
the chain of ASNs is not broken, i.e. they may not be contiguous
BGPsec peers but are still contiguous BGP peers.
Let us say that BGPsec capability was negotiated successfully between
two peers, and subsequently it was reset. In the meantime, assume
that the 4-byte ASN capability or the multi-protocol capability was
lost between the two peers. So now the BGPsec session reset results
in failure of BGPsec capability negotiation and only a BGP session is
established. Would the network operator be notified that this
downgrade from BGPsec to BGP has happened? What if the operator
always wants a secure session only? Can they require that no BGP
session be established if BGPsec capability negotiation fails?
Operators are advised to speak with their vendors to set up knobs and
alerts to have such operations and management features in their
BGPsec capable routers.
A peer that is an Internet Exchange Point (IXP) (i.e. Route Server)
with a transparent AS is expected to set pCount = 0 in its
Secure_Path segment while forwarding an update to a peer (see
Section 4.2). Clearly, such an IXP SHOULD configure itself to set
its own pCount = 0. As stated in Section 4.2, "BGPsec speakers
SHOULD drop incoming update messages with pCount set to zero in cases
where the BGPsec speaker does not expect its peer to set pCount to
zero." This means that a BGPsec speaker SHOULD be configured so that
it permits pCount =0 from an IXP peer and never permits pCount = 0
from a peer that is not an IXP.
During the validation of a BGPsec update, route processor performance
speedup can be achieved by incorporating the following observations.
An update is deemed 'Valid' if at least one of the Signature_Blocks
is marked as 'Valid' (see Section 5.2). Therefore, if an update
contains two Signature_Blocks and the first one verified is found
'Valid', then the second Signature_Block does not have to be
verified. And if the update were chosen for best path, then the
BGPsec speaker adds its signature (generated with the respective
algorithm) to each of the two Signature_Blocks and forwards the
update. Also, a BGPsec update is deemed 'Not Valid' if at least one
signature in each of the Signature_Blocks is invalid. This principle
can also be used for route processor workload savings, i.e. the
verification for a Signature_Block terminates early when the first
invalid signature is encountered.
With regards to the processing of duplicate BGPsec update messages,
Section 5 stated, "if the first update message is valid, then an
implementation SHOULD NOT run the validation procedure on the
duplicate update". If validity of the duplicate were computed and
found 'Valid', then it gives the router no new information.
Alternatively, if it were found 'Not Valid', then it only implies
that some bit errors occurred in the signatures. Therefore, the
BGPsec speaker should keep the 'Valid' original update and ignore the
duplicate. However, if the original update were 'Not Valid', then
performing validation of the duplicate is relevant and SHOULD be
done.
How will migration from BGP to BGPsec look like? What are the
benefits for the first adopters? Initially small groups of
contiguous ASes would be doing BGPsec. There would be possibly one
or more such groups in different geographic regions of the global
Internet. Only the routes originated within each group and
propagated within its borders would get the benefits of cryptographic
AS path protection. As BGPsec adoption grows, each group grows in
size and eventually they join together to form even larger BGPsec
capable groups of contiguous ASes. The benefit for early adopters
starts with AS path security within the contiguous-AS regions spanned
by their respective groups. Over time they would see those
contiguous-AS regions grow much larger.
8. Security Considerations
For a discussion of the BGPsec threat model and related security For a discussion of the BGPsec threat model and related security
considerations, please see RFC 7132 [RFC7132]. considerations, please see RFC 7132 [RFC7132].
7.1. Security Guarantees 8.1. Security Guarantees
When used in conjunction with Origin Validation (see RFC 6483 When used in conjunction with Origin Validation (see RFC 6483
[RFC6483] and RFC 6811 [RFC6811]), a BGPsec speaker who receives a [RFC6483] and RFC 6811 [RFC6811]), a BGPsec speaker who receives a
valid BGPsec update message, containing a route advertisement for a valid BGPsec update message, containing a route advertisement for a
given prefix, is provided with the following security guarantees: given prefix, is provided with the following security guarantees:
o The origin AS number corresponds to an autonomous system that has o The origin AS number corresponds to an autonomous system that has
been authorized, in the RPKI, by the IP address space holder to been authorized, in the RPKI, by the IP address space holder to
originate route advertisements for the given prefix. originate route advertisements for the given prefix.
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use of such a mechanism to influence route selection is completely a use of such a mechanism to influence route selection is completely a
matter of local policy. Therefore, a BGPsec speaker can make no matter of local policy. Therefore, a BGPsec speaker can make no
assumptions about the validity of a route received from an external assumptions about the validity of a route received from an external
BGPsec peer. That is, a compliant BGPsec peer may (depending on the BGPsec peer. That is, a compliant BGPsec peer may (depending on the
local policy of the peer) send update messages that fail the validity local policy of the peer) send update messages that fail the validity
test in Section 5. Thus, a BGPsec speaker MUST completely validate test in Section 5. Thus, a BGPsec speaker MUST completely validate
all BGPsec update messages received from external peers. (Validation all BGPsec update messages received from external peers. (Validation
of update messages received from internal peers is a matter of local of update messages received from internal peers is a matter of local
policy, see Section 5). policy, see Section 5).
7.2. On the Removal of BGPsec Signatures 8.2. On the Removal of BGPsec Signatures
There may be cases where a BGPsec speaker deems 'Valid' (as per the There may be cases where a BGPsec speaker deems 'Valid' (as per the
validation algorithm in Section 5.2) a BGPsec update message that validation algorithm in Section 5.2) a BGPsec update message that
contains both a 'Valid' and a 'Not Valid' Signature_Block. That is, contains both a 'Valid' and a 'Not Valid' Signature_Block. That is,
the update message contains two sets of signatures corresponding to the update message contains two sets of signatures corresponding to
two algorithm suites, and one set of signatures verifies correctly two algorithm suites, and one set of signatures verifies correctly
and the other set of signatures fails to verify. In this case, the and the other set of signatures fails to verify. In this case, the
protocol specifies that a BGPsec speaker choosing to propagate the protocol specifies that a BGPsec speaker choosing to propagate the
route advertisement in such an update message SHOULD add its route advertisement in such an update message should add its
signature to each of the Signature_Blocks. Thus the BGPsec speaker signature to each of the Signature_Blocks (see Section 4.2). Thus
creates a signature using both algorithm suites and creates a new the BGPsec speaker creates a signature using both algorithm suites
update message that contains both the 'Valid' and the 'Not Valid' set and creates a new update message that contains both the 'Valid' and
of signatures (from its own vantage point). the 'Not Valid' set of signatures (from its own vantage point).
To understand the reason for such a design decision consider the case To understand the reason for such a design decision, consider the
where the BGPsec speaker receives an update message with both a set case where the BGPsec speaker receives an update message with both a
of algorithm A signatures which are 'Valid' and a set of algorithm B set of algorithm A signatures which are 'Valid' and a set of
signatures which are 'Not Valid'. In such a case it is possible algorithm B signatures which are 'Not Valid'. In such a case it is
(perhaps even likely, depending on the state of the algorithm possible (perhaps even likely, depending on the state of the
transition) that some of the BGPsec speaker's peers (or other algorithm transition) that some of the BGPsec speaker's peers (or
entities further 'downstream' in the BGP topology) do not support other entities further 'downstream' in the BGP topology) do not
algorithm A. Therefore, if the BGPsec speaker were to remove the support algorithm A. Therefore, if the BGPsec speaker were to remove
'Not Valid' set of signatures corresponding to algorithm B, such the 'Not Valid' set of signatures corresponding to algorithm B, such
entities would treat the message as though it were unsigned. By entities would treat the message as though it were unsigned. By
including the 'Not Valid' set of signatures when propagating a route including the 'Not Valid' set of signatures when propagating a route
advertisement, the BGPsec speaker ensures that 'downstream' entities advertisement, the BGPsec speaker ensures that 'downstream' entities
have as much information as possible to make an informed opinion have as much information as possible to make an informed opinion
about the validation status of a BGPsec update. about the validation status of a BGPsec update.
Note also that during a period of partial BGPsec deployment, a Note also that during a period of partial BGPsec deployment, a
'downstream' entity might reasonably treat unsigned messages 'downstream' entity might reasonably treat unsigned messages
differently from BGPsec updates that contain a single set of 'Not differently from BGPsec updates that contain a single set of 'Not
Valid' signatures. That is, by removing the set of 'Not Valid' Valid' signatures. That is, by removing the set of 'Not Valid'
skipping to change at page 30, line 20 skipping to change at page 33, line 12
that due to possible differences in RPKI data observed at different that due to possible differences in RPKI data observed at different
vantage points in the network, a BGPsec update deemed 'Not Valid' at vantage points in the network, a BGPsec update deemed 'Not Valid' at
an upstream BGPsec speaker may be deemed 'Valid' by another BGP an upstream BGPsec speaker may be deemed 'Valid' by another BGP
speaker downstream. speaker downstream.
Indeed, when a BGPsec speaker signs an outgoing update message, it is Indeed, when a BGPsec speaker signs an outgoing update message, it is
not attesting to a belief that all signatures prior to its are valid. not attesting to a belief that all signatures prior to its are valid.
Instead it is merely asserting that: Instead it is merely asserting that:
o The BGPsec speaker received the given route advertisement with the o The BGPsec speaker received the given route advertisement with the
indicated NLRI and Secure_Path; and indicated prefix, AFI, SAFI, and Secure_Path; and
o The BGPsec speaker chose to propagate an advertisement for this o The BGPsec speaker chose to propagate an advertisement for this
route to the peer (implicitly) indicated by the 'Target AS'. route to the peer (implicitly) indicated by the 'Target AS
Number'.
7.3. Mitigation of Denial of Service Attacks 8.3. Mitigation of Denial of Service Attacks
The BGPsec update validation procedure is a potential target for The BGPsec update validation procedure is a potential target for
denial of service attacks against a BGPsec speaker. Here we consider denial of service attacks against a BGPsec speaker. The mitigation
the mitigation only of denial of service attacks that are specific to of denial of service attacks that are specific to the BGPsec protocol
BGPsec. is considered here.
To mitigate the effectiveness of such denial of service attacks, To mitigate the effectiveness of such denial of service attacks,
BGPsec speakers should implement an update validation algorithm that BGPsec speakers should implement an update validation algorithm that
performs expensive checks (e.g., signature verification) after performs expensive checks (e.g., signature verification) after
performing less expensive checks (e.g., syntax checks). The performing less expensive checks (e.g., syntax checks). The
validation algorithm specified in Section 5.2 was chosen so as to validation algorithm specified in Section 5.2 was chosen so as to
perform checks which are likely to be expensive after checks that are perform checks which are likely to be expensive after checks that are
likely to be inexpensive. However, the relative cost of performing likely to be inexpensive. However, the relative cost of performing
required validation steps may vary between implementations, and thus required validation steps may vary between implementations, and thus
the algorithm specified in Section 5.2 may not provide the best the algorithm specified in Section 5.2 may not provide the best
skipping to change at page 31, line 9 skipping to change at page 34, line 5
to verify signatures as soon as an invalid signature is found. (This to verify signatures as soon as an invalid signature is found. (This
ensures that long sequences of invalid signatures cannot be used for ensures that long sequences of invalid signatures cannot be used for
denial of service attacks.) Furthermore, implementations can denial of service attacks.) Furthermore, implementations can
mitigate such attacks by only performing validation on update mitigate such attacks by only performing validation on update
messages that, if valid, would be selected as the best path. That messages that, if valid, would be selected as the best path. That
is, if an update message contains a route that would lose out in best is, if an update message contains a route that would lose out in best
path selection for other reasons (e.g., a very long AS path) then it path selection for other reasons (e.g., a very long AS path) then it
is not necessary to determine the BGPsec-validity status of the is not necessary to determine the BGPsec-validity status of the
route. route.
7.4. Additional Security Considerations 8.4. Additional Security Considerations
The mechanism of setting the pCount field to zero is included in this The mechanism of setting the pCount field to zero is included in this
specification to enable route servers in the control path to specification to enable route servers in the control path to
participate in BGPsec without increasing the effective length of the participate in BGPsec without increasing the length of the AS path.
AS-PATH. However, entities other than route servers could However, entities other than route servers could conceivably use this
conceivably use this mechanism (set the pCount to zero) to attract mechanism (set the pCount to zero) to attract traffic (by reducing
traffic (by reducing the effective length of the AS-PATH) the length of the AS path) illegitimately. This risk is largely
illegitimately. This risk is largely mitigated if every BGPsec mitigated if every BGPsec speaker drops incoming update messages that
speaker drops incoming update messages that set pCount to zero but set pCount to zero but come from a peer that is not a route server.
come from a peer that is not a route server. However, note that a However, note that a recipient of a BGPsec update message within
recipient of a BGPsec update message within which an upstream entity which an upstream entity two or more hops away has set pCount to zero
two or more hops away has set pCount to zero is unable to verify for is unable to verify for themselves whether pCount was set to zero
themselves whether pCount was set to zero legitimately. legitimately.
When a BGPsec router (outside of a confederation) is forwarding an
update to a member of the confederation, it signs the update to the
public ASN of the confederation and not to the member's ASN (see
Section 4.3). This can possibly raise a minor security concern. For
example, said member can tunnel the signed update to another member
as is (i.e. without adding a signature). The update can then be
propagated using BGPsec to other confederation members or to BGPsec
neighbors outside of the confederation. This kind of operation is
possible, but no grave security or reachability compromise is feared
due to the following reasons: (1) The confederation members belong to
one organization and strong internal trust is expected; and (2)
Recall that the signatures that are internal to the confederation
must be removed prior to forwarding the update to an outside BGPsec
router (see Section 4.3).
BGPsec does not provide protection against attacks at the transport BGPsec does not provide protection against attacks at the transport
layer. As with any BGP session, an adversary on the path between a layer. As with any BGP session, an adversary on the path between a
BGPsec speaker and its peer is able to perform attacks such as BGPsec speaker and its peer is able to perform attacks such as
modifying valid BGPsec updates to cause them to fail validation, modifying valid BGPsec updates to cause them to fail validation,
injecting (unsigned) BGP update messages without BGPsec_Path injecting (unsigned) BGP update messages without BGPsec_Path
attributes, injecting BGPsec update messages with BGPsec_Path attributes, injecting BGPsec update messages with BGPsec_Path
attributes that fail validation, or causing the peer to tear-down the attributes that fail validation, or causing the peer to tear-down the
BGP session. The use of BGPsec does nothing to increase the power of BGP session. The use of BGPsec does nothing to increase the power of
an on-path adversary -- in particular, even an on-path adversary an on-path adversary -- in particular, even an on-path adversary
cannot cause a BGPsec speaker to believe a BGPsec-invalid route is cannot cause a BGPsec speaker to believe a BGPsec-invalid route is
valid. However, as with any BGP session, BGPsec sessions SHOULD be valid. However, as with any BGP session, BGPsec sessions SHOULD be
protected by appropriate transport security mechanisms. protected by appropriate transport security mechanisms (see the
Security Considerations section in [RFC4271]).
8. IANA Considerations There is a possibility of replay attacks which are defined as
follows. In the context of BGPsec, a replay attack occurs when a
malicious BGPsec speaker in the AS path suppresses a prefix
withdrawal (implicit or explicit). Further, a replay attack is said
to occur also when a malicious BGPsec speaker replays a previously
received BGPsec announcement for a prefix that has since been
withdrawn. The mitigation strategy for replay attacks involves
router certificate rollover; please see
[I-D.ietf-sidr-bgpsec-rollover] for details.
This document registers a new capability in the registry of BGP 9. IANA Considerations
Capabilities. The description for the new capability is "BGPsec
Capability". The reference for the new capability is this document
(i.e., the RFC that replaces draft-ietf-sidr-bgpsec-protocol), see
Section 2.1.
This document registers a new path attribute in the registry of BGP IANA is requested to register a new BGP capability from Section 2.1
Path Attributes. The code for this new attribute is "BGPsec_Path". in the BGP Capabilities Code registry's "IETF Review" range. The
The reference for the new capability is this document (i.e., the RFC description for the new capability is "BGPsec Capability". The
that replaces draft-ietf-sidr-bgpsec-protocol), see Section 3. reference for the new capability is this document (i.e. the RFC that
replaces draft-ietf-sidr-bgpsec-protocol).
This document does not create any new IANA registries. IANA is also requested to register a new path attribute from
Section 3 in the BGP Path Attributes registry. The code for this new
attribute is "BGPsec_Path". The reference for the new capability is
this document (i.e. the RFC that replaces draft-ietf-sidr-bgpsec-
protocol).
9. Contributors IANA is requested to define the "BGPsec Capability" registry in the
Resource Public Key Infrastructure (RPKI) group. The registry is as
shown in Figure 10 with values assigned from Section 2.1:
9.1. Authors +------+---------------+------------+
| Bits | Field | Reference |
+------+---------------+------------+
| 0-3 | Version | [This RFC] |
| +---------------+------------+
| | Value = 0x0 | [This RFC] |
+------+---------------+------------+
| 4 | Direction | [This RFC] |
+------+---------------+------------+
| 5-7 | Reserved | [This RFC] |
+------+---------------+------------+
Figure 10: IANA registry for BGPsec Capability.
Future Version values and future values of the Reserved bits are
assigned using the "IETF Review" registration procedures defined in
RFC 5226 [RFC5226].
IANA is requested to define the "BGPsec_Path Flags" registry in the
RPKI group. The registry is as shown in Figure 11 with one value
assigned from Section 3.1:
+------+---------------------------+------------+
| Flag | Description | Reference |
+------+---------------------------+------------+
| 0 | Confed_Segment | [This RFC] |
+------+---------------------------+------------+
| 1-7 | Unassigned (set to zeros) | |
+------+---------------------------+------------+
Figure 11: IANA registry for BGPsec_Path Flags field.
Future values of the Unassigned bits are assigned using the "IETF
Review" registration procedures defined in RFC 5226 [RFC5226].
10. Contributors
10.1. Authors
Rob Austein Rob Austein
Dragon Research Labs Dragon Research Labs
sra@hactrn.net sra@hactrn.net
Steven Bellovin Steven Bellovin
Columbia University Columbia University
smb@cs.columbia.edu smb@cs.columbia.edu
Randy Bush Randy Bush
skipping to change at page 32, line 40 skipping to change at page 37, line 4
BBN Technologies BBN Technologies
kent@bbn.com kent@bbn.com
Warren Kumari Warren Kumari
Google Google
warren@kumari.net warren@kumari.net
Doug Montgomery Doug Montgomery
USA National Institute of Standards and Technology USA National Institute of Standards and Technology
dougm@nist.gov dougm@nist.gov
Kotikalapudi Sriram Kotikalapudi Sriram
USA National Institute of Standards and Technology USA National Institute of Standards and Technology
kotikalapudi.sriram@nist.gov kotikalapudi.sriram@nist.gov
Samuel Weiler Samuel Weiler
Parsons Parsons
weiler+ietf@watson.org weiler+ietf@watson.org
9.2. Acknowledgements 10.2. Acknowledgements
The authors would like to thank Michael Baer, Luke Berndt, Oliver The authors would like to thank Michael Baer, Oliver Borchert, David
Borchert, Wes George, Jeff Haas, Sharon Goldberg, Ed Kern, David Mandelberg, Sean Turner, John Scudder, Wes George, Jeff Haas, Keyur
Mandelberg, Doug Maughan, Pradosh Mohapatra, Chris Morrow, Russ Patel, Sandy Murphy, Chris Morrow, Russ Mundy, Wes Hardaker, Sharon
Mundy, Sandy Murphy, Keyur Patel, Mark Reynolds, Heather Schiller, Goldberg, Ed Kern, Doug Maughan, Pradosh Mohapatra, Mark Reynolds,
Jason Schiller, John Scudder, Ruediger Volk and David Ward for their Heather Schiller, Jason Schiller, Ruediger Volk and David Ward for
valuable input and review. their review, comments, and suggestions during the course of this
work.
10. References 11. References
10.1. Normative References 11.1. Normative References
[I-D.ietf-idr-bgp-extended-messages] [I-D.ietf-idr-bgp-extended-messages]
Bush, R., Patel, K., and D. Ward, "Extended Message Bush, R., Patel, K., and D. Ward, "Extended Message
support for BGP", draft-ietf-idr-bgp-extended-messages-13 support for BGP", draft-ietf-idr-bgp-extended-messages-13
(work in progress), June 2016. (work in progress), June 2016.
[I-D.ietf-sidr-bgpsec-algs] [I-D.ietf-sidr-bgpsec-algs]
Turner, S., "BGPsec Algorithms, Key Formats, & Signature Turner, S., "BGPsec Algorithms, Key Formats, & Signature
Formats", draft-ietf-sidr-bgpsec-algs-15 (work in Formats", draft-ietf-sidr-bgpsec-algs-16 (work in
progress), April 2016. progress), November 2016.
[I-D.ietf-sidr-bgpsec-pki-profiles] [I-D.ietf-sidr-bgpsec-pki-profiles]
Reynolds, M., Turner, S., and D. Kent, "A Profile for Reynolds, M., Turner, S., and S. Kent, "A Profile for
BGPsec Router Certificates, Certificate Revocation Lists, BGPsec Router Certificates, Certificate Revocation Lists,
and Certification Requests", draft-ietf-sidr-bgpsec-pki- and Certification Requests", draft-ietf-sidr-bgpsec-pki-
profiles-18 (work in progress), July 2016. profiles-18 (work in progress), July 2016.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>. <http://www.rfc-editor.org/info/rfc2119>.
[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A [RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
skipping to change at page 34, line 24 skipping to change at page 38, line 34
[RFC6793] Vohra, Q. and E. Chen, "BGP Support for Four-Octet [RFC6793] Vohra, Q. and E. Chen, "BGP Support for Four-Octet
Autonomous System (AS) Number Space", RFC 6793, Autonomous System (AS) Number Space", RFC 6793,
DOI 10.17487/RFC6793, December 2012, DOI 10.17487/RFC6793, December 2012,
<http://www.rfc-editor.org/info/rfc6793>. <http://www.rfc-editor.org/info/rfc6793>.
[RFC7606] Chen, E., Ed., Scudder, J., Ed., Mohapatra, P., and K. [RFC7606] Chen, E., Ed., Scudder, J., Ed., Mohapatra, P., and K.
Patel, "Revised Error Handling for BGP UPDATE Messages", Patel, "Revised Error Handling for BGP UPDATE Messages",
RFC 7606, DOI 10.17487/RFC7606, August 2015, RFC 7606, DOI 10.17487/RFC7606, August 2015,
<http://www.rfc-editor.org/info/rfc7606>. <http://www.rfc-editor.org/info/rfc7606>.
10.2. Informative References 11.2. Informative References
[I-D.ietf-sidr-as-migration] [I-D.ietf-sidr-as-migration]
George, W. and S. Murphy, "BGPSec Considerations for AS George, W. and S. Murphy, "BGPSec Considerations for AS
Migration", draft-ietf-sidr-as-migration-05 (work in Migration", draft-ietf-sidr-as-migration-05 (work in
progress), April 2016. progress), April 2016.
[I-D.ietf-sidr-bgpsec-ops] [I-D.ietf-sidr-bgpsec-ops]
Bush, R., "BGPsec Operational Considerations", draft-ietf- Bush, R., "BGPsec Operational Considerations", draft-ietf-
sidr-bgpsec-ops-10 (work in progress), June 2016. sidr-bgpsec-ops-10 (work in progress), June 2016.
[I-D.ietf-sidr-bgpsec-rollover]
Gagliano, R., Weis, B., and K. Patel, "BGPsec Router
Certificate Rollover", draft-ietf-sidr-bgpsec-rollover-06
(work in progress), October 2016.
[I-D.ietf-sidr-rpki-rtr-rfc6810-bis] [I-D.ietf-sidr-rpki-rtr-rfc6810-bis]
Bush, R. and R. Austein, "The Resource Public Key Bush, R. and R. Austein, "The Resource Public Key
Infrastructure (RPKI) to Router Protocol", draft-ietf- Infrastructure (RPKI) to Router Protocol", draft-ietf-
sidr-rpki-rtr-rfc6810-bis-07 (work in progress), March sidr-rpki-rtr-rfc6810-bis-07 (work in progress), March
2016. 2016.
[I-D.ietf-sidr-rtr-keying] [I-D.ietf-sidr-rtr-keying]
Bush, R., Turner, S., and K. Patel, "Router Keying for Bush, R., Turner, S., and K. Patel, "Router Keying for
BGPsec", draft-ietf-sidr-rtr-keying-12 (work in progress), BGPsec", draft-ietf-sidr-rtr-keying-12 (work in progress),
June 2016. June 2016.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
DOI 10.17487/RFC5226, May 2008,
<http://www.rfc-editor.org/info/rfc5226>.
[RFC6472] Kumari, W. and K. Sriram, "Recommendation for Not Using [RFC6472] Kumari, W. and K. Sriram, "Recommendation for Not Using
AS_SET and AS_CONFED_SET in BGP", BCP 172, RFC 6472, AS_SET and AS_CONFED_SET in BGP", BCP 172, RFC 6472,
DOI 10.17487/RFC6472, December 2011, DOI 10.17487/RFC6472, December 2011,
<http://www.rfc-editor.org/info/rfc6472>. <http://www.rfc-editor.org/info/rfc6472>.
[RFC6480] Lepinski, M. and S. Kent, "An Infrastructure to Support [RFC6480] Lepinski, M. and S. Kent, "An Infrastructure to Support
Secure Internet Routing", RFC 6480, DOI 10.17487/RFC6480, Secure Internet Routing", RFC 6480, DOI 10.17487/RFC6480,
February 2012, <http://www.rfc-editor.org/info/rfc6480>. February 2012, <http://www.rfc-editor.org/info/rfc6480>.
[RFC6483] Huston, G. and G. Michaelson, "Validation of Route [RFC6483] Huston, G. and G. Michaelson, "Validation of Route
Origination Using the Resource Certificate Public Key Origination Using the Resource Certificate Public Key
Infrastructure (PKI) and Route Origin Authorizations Infrastructure (PKI) and Route Origin Authorizations
(ROAs)", RFC 6483, DOI 10.17487/RFC6483, February 2012, (ROAs)", RFC 6483, DOI 10.17487/RFC6483, February 2012,
<http://www.rfc-editor.org/info/rfc6483>. <http://www.rfc-editor.org/info/rfc6483>.
[RFC6487] Huston, G., Michaelson, G., and R. Loomans, "A Profile for
X.509 PKIX Resource Certificates", RFC 6487,
DOI 10.17487/RFC6487, February 2012,
<http://www.rfc-editor.org/info/rfc6487>.
[RFC6811] Mohapatra, P., Scudder, J., Ward, D., Bush, R., and R. [RFC6811] Mohapatra, P., Scudder, J., Ward, D., Bush, R., and R.
Austein, "BGP Prefix Origin Validation", RFC 6811, Austein, "BGP Prefix Origin Validation", RFC 6811,
DOI 10.17487/RFC6811, January 2013, DOI 10.17487/RFC6811, January 2013,
<http://www.rfc-editor.org/info/rfc6811>. <http://www.rfc-editor.org/info/rfc6811>.
[RFC7132] Kent, S. and A. Chi, "Threat Model for BGP Path Security", [RFC7132] Kent, S. and A. Chi, "Threat Model for BGP Path Security",
RFC 7132, DOI 10.17487/RFC7132, February 2014, RFC 7132, DOI 10.17487/RFC7132, February 2014,
<http://www.rfc-editor.org/info/rfc7132>. <http://www.rfc-editor.org/info/rfc7132>.
Authors' Addresses Authors' Addresses
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