draft-ietf-sidr-bgpsec-protocol-17.txt   draft-ietf-sidr-bgpsec-protocol-18.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: December 23, 2016 NIST Expires: February 19, 2017 NIST
June 23, 2016 August 18, 2016
BGPsec Protocol Specification BGPsec Protocol Specification
draft-ietf-sidr-bgpsec-protocol-17 draft-ietf-sidr-bgpsec-protocol-18
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.
Requirements Language Status of This Memo
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" are to be interpreted as described in RFC 2119 [1] only
when they appear in all upper case. They may also appear in lower or
mixed case as English words, without normative meaning.
Status of this Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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 December 23, 2016. This Internet-Draft will expire on February 19, 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
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. BGPsec Negotiation . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2.1. The BGPsec Capability . . . . . . . . . . . . . . . . . . 3 2. BGPsec Negotiation . . . . . . . . . . . . . . . . . . . . . 3
2.2. Negotiating BGPsec Support . . . . . . . . . . . . . . . . 4 2.1. The BGPsec Capability . . . . . . . . . . . . . . . . . . 3
3. The BGPsec_Path Attribute . . . . . . . . . . . . . . . . . . 6 2.2. Negotiating BGPsec Support . . . . . . . . . . . . . . . 4
3.1. Secure_Path . . . . . . . . . . . . . . . . . . . . . . . 7 3. The BGPsec_Path Attribute . . . . . . . . . . . . . . . . . . 6
3.2. Signature_Block . . . . . . . . . . . . . . . . . . . . . 8 3.1. Secure_Path . . . . . . . . . . . . . . . . . . . . . . . 8
4. BGPsec Update Messages . . . . . . . . . . . . . . . . . . . . 10 3.2. Signature_Block . . . . . . . . . . . . . . . . . . . . . 9
4.1. General Guidance . . . . . . . . . . . . . . . . . . . . . 10 4. BGPsec Update Messages . . . . . . . . . . . . . . . . . . . 10
4.2. Constructing the BGPsec_Path Attribute . . . . . . . . . . 12 4.1. General Guidance . . . . . . . . . . . . . . . . . . . . 11
4.3. Processing Instructions for Confederation Members . . . . 16 4.2. Constructing the BGPsec_Path Attribute . . . . . . . . . 13
4.4. Reconstructing the AS_PATH Attribute . . . . . . . . . . . 18 4.3. Processing Instructions for Confederation Members . . . . 17
5. Processing a Received BGPsec Update . . . . . . . . . . . . . 20 4.4. Reconstructing the AS_PATH Attribute . . . . . . . . . . 19
5.1. Overview of BGPsec Validation . . . . . . . . . . . . . . 21 5. Processing a Received BGPsec Update . . . . . . . . . . . . . 20
5.2. Validation Algorithm . . . . . . . . . . . . . . . . . . . 22 5.1. Overview of BGPsec Validation . . . . . . . . . . . . . . 22
6. Algorithms and Extensibility . . . . . . . . . . . . . . . . . 25 5.2. Validation Algorithm . . . . . . . . . . . . . . . . . . 23
6.1. Algorithm Suite Considerations . . . . . . . . . . . . . . 25 6. Algorithms and Extensibility . . . . . . . . . . . . . . . . 26
6.2. Extensibility Considerations . . . . . . . . . . . . . . . 26 6.1. Algorithm Suite Considerations . . . . . . . . . . . . . 26
7. Security Considerations . . . . . . . . . . . . . . . . . . . 27 6.2. Extensibility Considerations . . . . . . . . . . . . . . 27
7.1 Security Guarantees . . . . . . . . . . . . . . . . . . . . 27 7. Security Considerations . . . . . . . . . . . . . . . . . . . 28
7.2 On the Removal of BGPsec Signatures . . . . . . . . . . . . 28 7.1. Security Guarantees . . . . . . . . . . . . . . . . . . . 28
7.3 Mitigation of Denial of Service Attacks . . . . . . . . . . 29 7.2. On the Removal of BGPsec Signatures . . . . . . . . . . . 29
7.4 Additional Security Considerations . . . . . . . . . . . . . 30 7.3. Mitigation of Denial of Service Attacks . . . . . . . . . 30
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 30 7.4. Additional Security Considerations . . . . . . . . . . . 31
9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 31 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 31
9.1. Authors . . . . . . . . . . . . . . . . . . . . . . . . . 31 9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 32
9.2. Acknowledgements . . . . . . . . . . . . . . . . . . . . . 32 9.1. Authors . . . . . . . . . . . . . . . . . . . . . . . . . 32
10. Normative References . . . . . . . . . . . . . . . . . . . . 32 9.2. Acknowledgements . . . . . . . . . . . . . . . . . . . . 33
11. Informative References . . . . . . . . . . . . . . . . . . . 33 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 33
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 34 10.1. Normative References . . . . . . . . . . . . . . . . . . 33
10.2. Informative References . . . . . . . . . . . . . . . . . 34
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 35
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) [2] route advertisements. security for Border Gateway Protocol (BGP) [RFC4271] route
That is, a BGP speaker who receives a valid BGPsec update has advertisements. That is, a BGP speaker who receives a valid BGPsec
cryptographic assurance that the advertised route has the following update has cryptographic assurance that the advertised route has the
property: Every AS on the path of ASes listed in the update message following property: Every AS on the path of ASes listed in the update
has explicitly authorized the advertisement of the route to the message has explicitly authorized the advertisement of the route to
subsequent AS in the path. the subsequent AS in the path.
This document specifies an optional (non-transitive) BGP path This document specifies an optional (non-transitive) BGP path
attribute, BGPsec_Path. It also describes how a BGPsec-compliant BGP attribute, BGPsec_Path. It also describes how a BGPsec-compliant BGP
speaker (referred to hereafter as a BGPsec speaker) can generate, speaker (referred to hereafter as a BGPsec speaker) can generate,
propagate, and validate BGP update messages containing this attribute propagate, and validate BGP update messages containing this attribute
to obtain the above assurances. to obtain the above assurances.
BGPsec is intended to be used to supplement BGP Origin Validation BGPsec is intended to be used to supplement BGP Origin Validation
[19][20] and when used in conjunction with origin validation, it is [RFC6483][RFC6811] and when used in conjunction with origin
possible to prevent a wide variety of route hijacking attacks against validation, it is possible to prevent a wide variety of route
BGP. hijacking attacks against BGP.
BGPsec relies on the Resource Public Key Infrastructure (RPKI) BGPsec relies on the Resource Public Key Infrastructure (RPKI)
certificates that attest to the allocation of AS number and IP certificates that attest to the allocation of AS number and IP
address resources. (For more information on the RPKI, see [12] and address resources. (For more information on the RPKI, see RFC 6480
the documents referenced therein.) Any BGPsec speaker who wishes to [RFC6480] and the documents referenced therein.) Any BGPsec speaker
send, to external (eBGP) peers, BGP update messages containing the who wishes to send, to external (eBGP) peers, BGP update messages
BGPsec_Path needs to possess a private key associated with an RPKI containing the BGPsec_Path needs to possess a private key associated
router certificate [9] that corresponds to the BGPsec speaker's AS with an RPKI router certificate [I-D.ietf-sidr-bgpsec-pki-profiles]
number. Note, however, that a BGPsec speaker does not need such a that corresponds to the BGPsec speaker's AS number. Note, however,
certificate in order to validate received update messages containing that a BGPsec speaker does not need such a certificate in order to
the BGPsec_Path attribute (see Section 5.2). validate received update messages containing the BGPsec_Path
attribute (see Section 5.2).
1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
2. BGPsec Negotiation 2. BGPsec Negotiation
This document defines a BGP capability [6] that allows a BGP speaker This document defines a BGP capability [RFC5492] that allows a BGP
to advertise to a neighbor the ability to send or to receive BGPsec speaker to advertise to a neighbor the ability to send or to receive
update messages (i.e., update messages containing the BGPsec_Path BGPsec update messages (i.e., update messages containing the
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 value are specified as follows.
BGPsec Send Capability Value: 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 -----+
| | | |
+---------------------------------------+ +---------------------------------------+
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
update messages or receive BGPsec update messages. The BGP speaker update messages or receive BGPsec update messages. The BGP speaker
sets this bit to 0 to indicate the capability to receive BGPsec sets this bit to 0 to indicate the capability to receive BGPsec
update messages. The BGP speaker sets this bit to 1 to indicate the update messages. The BGP speaker sets this bit to 1 to indicate the
capability to send BGPsec update messages. capability to send BGPsec update messages.
The remaining three bits of the first octet are reserved for future The remaining three bits of the first octet are reserved for future
use. These bits are set to zero by the sender of the capability and use. These bits are set to zero by the sender of the capability and
ignored by the receiver of the capability. ignored by the receiver of the capability.
The second and third octets contain the 16-bit Address Family The second and third octets contain the 16-bit Address Family
Identifier (AFI) which indicates the address family for which the Identifier (AFI) which indicates the address family for which the
BGPsec speaker is advertising support for BGPsec. This document only BGPsec speaker is advertising support for BGPsec. This document only
specifies BGPsec for use with two address families, IPv4 and IPv6, specifies BGPsec for use with two address families, IPv4 and IPv6,
AFI values 1 and 2 respectively. BGPsec for use with other address AFI values 1 and 2 respectively. BGPsec for use with other address
families may be specified in future documents. families may be specified in future documents.
2.2. Negotiating BGPsec Support 2.2. Negotiating BGPsec Support
In order to indicate that a BGP speaker is willing to send BGPsec In order to indicate that a BGP speaker is willing to send BGPsec
update messages (for a particular address family), a BGP speaker update messages (for a particular address family), a BGP speaker
sends the BGPsec Capability (see Section 2.1) with the Direction bit sends the BGPsec Capability (see Section 2.1) with the Direction bit
(the fifth bit of the first octet) set to 1. In order to indicate (the fifth bit of the first octet) set to 1. In order to indicate
that the speaker is willing to receive BGP update messages containing that the speaker is willing to receive BGP update messages containing
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 MUST
support the BGP multiprotocol extension [3]. Additionally, a BGP support the BGP multiprotocol extension [RFC4760]. Additionally, a
speaker MUST NOT advertise the capability of BGPsec support for a BGP speaker MUST NOT advertise the capability of BGPsec support for a
particular AFI unless it has also advertised the multiprotocol particular AFI unless it has also advertised the multiprotocol
extension capability for the same AFI [3]. 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
skipping to change at page 5, line 42 skipping to change at page 5, line 44
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
for four-byte AS numbers. Therefore, any BGP speaker that announces for four-byte AS numbers. Therefore, any BGP speaker that announces
the BGPsec capability, MUST also announce the capability for four- the BGPsec capability, MUST also announce the capability for four-
byte AS support [4]. If a BGP speaker sends the BGPsec capability but byte AS support [RFC6793]. If a BGP speaker sends the BGPsec
not the four-byte AS support capability then BGPsec has not been capability but not the four-byte AS support capability then BGPsec
successfully negotiated, and update messages containing the has not been successfully negotiated, and update messages containing
BGPsec_Path attribute MUST NOT be sent within such a session. the BGPsec_Path attribute MUST NOT be sent within such a session.
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 [8]. 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 TBD
The BGPsec_Path attribute carries the secured information regarding The BGPsec_Path attribute carries the secured information regarding
skipping to change at page 7, line 18 skipping to change at page 7, line 46
BGPsec_Path Attribute 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) |
+-------------------------------------------------------+ +-------------------------------------------------------+
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
number (i.e., Secure_Path segment) in the Secure_Path. In the most number (i.e., Secure_Path segment) in the Secure_Path. In the most
common case, the BGPsec_Path attribute will contain only a single common case, the BGPsec_Path attribute will contain only a single
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
skipping to change at page 8, line 15 skipping to change at page 8, line 41
long. Note that this means the Secure_Path Length is two greater 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 than six times the number Secure_Path Segments (i.e., the number of
AS numbers in the path). AS numbers in the path).
The Secure_Path contains one Secure_Path Segment for each Autonomous The Secure_Path contains one Secure_Path Segment for each Autonomous
System in the path to the originating AS of the NLRI specified in the System in the path to the originating AS of the NLRI specified in the
update message. update message.
Secure_Path Segment Secure_Path Segment
+----------------------------+ +----------------------------+
| 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 The AS Number is the AS number of the BGP speaker that added this
Secure_Path segment to the BGPsec_Path attribute. (See Section 4 for Secure_Path segment to the BGPsec_Path attribute. (See Section 4 for
more information on populating this field.) 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. The pCount field is also
useful in managing route servers (see Section 4.2) and AS Number useful in managing route servers (see Section 4.2) and AS Number
migrations, see [18] for details. migrations, see [I-D.ietf-sidr-as-migration] for details.
The first bit of the Flags field is the Confed_Segment flag. The The first bit of the Flags field is the Confed_Segment flag. The
Confed_Segment flag is set to one to indicate that the BGPsec speaker Confed_Segment flag is set to one to indicate that the BGPsec speaker
that constructed this Secure_Path segment is sending the update that constructed this Secure_Path segment is sending the update
message to a peer AS within the same Autonomous System confederation message to a peer AS within the same Autonomous System confederation
[5]. (That is, the Confed_Segment flag is set in a BGPsec update [RFC5065]. (That is, the Confed_Segment flag is set in a BGPsec
message whenever, in a non-BGPsec update message, the BGP speaker's update message whenever, in a non-BGPsec update message, the BGP
AS would appear in a AS_PATH segment of type AS_CONFED_SEQUENCE.) In speaker's AS would appear in a AS_PATH segment of type
all other cases the Confed_Segment flag is set to zero. AS_CONFED_SEQUENCE.) In all other cases the 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 Here we provide a detailed description of the Signature_Blocks in the
BGPsec_Path attribute. BGPsec_Path attribute.
skipping to change at page 9, line 24 skipping to change at page 9, line 49
+---------------------------------------------+ +---------------------------------------------+
The Signature_Block Length is the total number of octets in the The Signature_Block Length is the total number of octets in the
Signature_Block (including the two octets used to express this length Signature_Block (including the two octets used to express this length
field). 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 [10]. algorithms document [I-D.ietf-sidr-bgpsec-algs].
A Signature_Block has exactly one Signature Segment for each A Signature_Block has exactly one Signature Segment for each
Secure_Path Segment in the Secure_Path portion of the BGPsec_Path Secure_Path Segment in the Secure_Path portion of the BGPsec_Path
Attribute. (That is, one Signature Segment for each distinct AS on Attribute. (That is, one Signature Segment for each distinct AS on
the path for the NLRI in the Update message.) the path for the NLRI in the Update message.)
Signature Segments Signature Segments
+---------------------------------------------+ +---------------------------------------------+
| Subject Key Identifier (20 octets) | | Subject Key Identifier (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 The Subject Key Identifier contains the value in the Subject Key
Identifier extension of the RPKI router certificate [9] that is used Identifier extension of the RPKI router certificate
to verify the signature (see Section 5 for details on validity of [I-D.ietf-sidr-bgpsec-pki-profiles] that is used to verify the
BGPsec update messages). 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 contains a digital signature that protects the NLRI and
the BGPsec_Path attribute (see Sections 4 and 5 for details on the BGPsec_Path attribute (see Section 4 and Section 5 for details on
signature generation and validation, respectively). 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 [5]. A BGPsec speaker that is not an autonomous system confederation [RFC5065]. A BGPsec speaker that
a member of such a confederation MUST set the Flags field of the is not a member of such a confederation MUST set the Flags field of
Secure_Path Segment to zero in all BGPsec update messages it sends. the Secure_Path Segment to 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
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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 NLRI.
This is because a BGPsec speaker receiving an update message with This is because a BGPsec speaker receiving an update message with
multiple NLRI would be unable to construct a valid BGPsec update multiple NLRI would be unable to construct a valid BGPsec update
message (i.e., valid path signatures) containing a subset of the NLRI message (i.e., valid path signatures) containing a subset of the NLRI
in the received update. If a BGPsec speaker wishes to advertise in the received update. If a BGPsec speaker wishes to advertise
routes to multiple NLRI, then it MUST generate a separate BGPsec routes to multiple NLRI, then it MUST generate a separate BGPsec
update message for each NLRI. Additionally, a BGPsec update message update message for each NLRI. Additionally, a BGPsec update message
MUST use the MP_REACH_NLRI [3] attribute to encode the NLRI. MUST use the MP_REACH_NLRI [RFC4760] attribute to encode the NLRI.
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
suite. Additionally, this private key must correspond to the public suite. Additionally, this private key must correspond to the public
key in a valid Resource PKI end-entity certificate whose AS number key in a valid Resource PKI end-entity certificate whose AS number
resource extension includes the BGPsec speaker's AS number [9]. Note resource extension includes the BGPsec speaker's AS number
also that new signatures are only added to a BGPsec update message [I-D.ietf-sidr-bgpsec-pki-profiles]. Note also that new signatures
when a BGPsec speaker is generating an update message to send to an are only added to a BGPsec update message when a BGPsec speaker is
external peer (i.e., when the AS number of the peer is not equal to generating an update message to send to an external peer (i.e., when
the BGPsec speaker's own AS number). Therefore, a BGPsec speaker who the AS number of the peer is not equal to the BGPsec speaker's own AS
only sends BGPsec update messages to peers within its own AS does not number). Therefore, a BGPsec speaker who only sends BGPsec update
need to possess any private signature keys. messages to peers within its own AS does not need to possess any
private signature keys.
The Resource PKI enables the legitimate holder of IP address The Resource PKI enables the legitimate holder of IP address
prefix(es) to issue a signed object, called a Route Origination prefix(es) to issue a signed object, called a Route Origination
Authorization (ROA), that authorizes a given AS to originate routes Authorization (ROA), that authorizes a given AS to originate routes
to a given set of prefixes (see [7]). It is expected that most to a given set of prefixes (see RFC 6482 [RFC6482]). It is expected
relying parties will utilize BGPsec in tandem with origin validation that most relying parties will utilize BGPsec in tandem with origin
(see [19] and [20]). Therefore, it is RECOMMENDED that a BGPsec validation (see RFC 6483 [RFC6483] and RFC 6811 [RFC6811]).
speaker only originate a BGPsec update advertising a route for a Therefore, it is RECOMMENDED that a BGPsec speaker only originate a
given prefix if there exists a valid ROA authorizing the BGPsec BGPsec update advertising a route for a given prefix if there exists
speaker's AS to originate routes to this prefix. a valid ROA authorizing the BGPsec speaker's AS to originate routes
to this prefix.
If a BGPsec router has received only a non-BGPsec update message If a BGPsec router has received only a non-BGPsec update message
(without the BGPsec_Path attribute), containing the AS_PATH (without the BGPsec_Path attribute), containing the AS_PATH
attribute, from a peer for a given prefix then it MUST NOT attach a attribute, from a peer for a given prefix then it MUST NOT attach a
BGPsec_Path attribute when it propagates the update message. (Note BGPsec_Path attribute when it propagates the update message. (Note
that a BGPsec router may also receive a non-BGPsec update message that a BGPsec router may also receive a non-BGPsec update message
from an internal peer without the AS_PATH attribute, i.e., with just from an internal peer without the AS_PATH attribute, i.e., with just
the NLRI in it. In that case, the prefix is originating from that the NLRI in it. In that case, the prefix is originating from that
AS, and if it is selected for advertisement, the BGPsec speaker AS, and if it is selected for advertisement, the BGPsec speaker
SHOULD attach a BGPsec_Path attribute and send a signed route (for SHOULD attach a BGPsec_Path attribute and send a signed route (for
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security ramifications. (See Section 7 for discussion of the security ramifications. (See Section 7 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 Section the validation state of the update message it received. (See
7 for more discussion of the security semantics of BGPsec Section 7 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 [13] 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 propagating a received route
advertisement to an internal peer, the BGPsec speaker typically advertisement to an internal peer, the BGPsec speaker typically
populates the BGPsec_Path attribute by copying the BGPsec_Path populates the BGPsec_Path attribute by copying the BGPsec_Path
attribute from the received update message. That is, the BGPsec_Path attribute from the received update message. That is, the BGPsec_Path
attribute is copied verbatim. However, in the case that the BGPsec attribute is copied verbatim. However, in the case that the BGPsec
speaker is performing an AS Migration, the BGPsec speaker may add an speaker is performing an AS Migration, the BGPsec speaker may add an
additional signature on ingress before copying the BGPsec_Path additional signature on ingress before copying the BGPsec_Path
attribute (see [18] for more details). Note that when a BGPsec attribute (see [I-D.ietf-sidr-as-migration] for more details). Note
speaker chooses to forward a BGPsec update message to an iBGP peer, that when a BGPsec speaker chooses to forward a BGPsec update message
the BGPsec attribute SHOULD NOT be removed, unless the peer doesn't to an iBGP peer, the BGPsec attribute SHOULD NOT be removed, unless
support BGPsec. In particular, the BGPsec attribute SHOULD NOT be the peer doesn't support BGPsec. In particular, the BGPsec attribute
removed even in the case where the BGPsec update message has not been SHOULD NOT be removed even in the case where the BGPsec update
successfully validated. (See Section 5 for more information on message has not been successfully validated. (See Section 5 for more
validation, and Section 7 for the security ramifications of removing information on validation, and Section 7 for the security
BGPsec signatures.) 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 to its other (internal or external) peers. When sending by sending it to its other (internal or external) peers. When
said route advertisement to an internal BGPsec-speaking peer, the sending said route advertisement to an internal BGPsec-speaking peer,
BGPsec_Path attribute SHALL NOT be modified. When sending said route the BGPsec_Path attribute SHALL NOT be modified. When sending said
advertisement to an external BGPsec-speaking peer, the following route advertisement to an external BGPsec-speaking peer, the
procedures are used to form or update the BGPsec_Path attribute. following procedures are used to form or update the BGPsec_Path
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 AS number resource extension field of the Resource PKI router
certificate(s) that will be used to verify the digital signature(s) certificate(s) that will be used to verify the digital signature(s)
constructed by this BGPsec speaker [9]. constructed by this BGPsec speaker
[I-D.ietf-sidr-bgpsec-pki-profiles].
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 effective length of the AS path. (Note that BGPsec speakers compute
the effective length of the AS path by summing the pCount values in the effective length of the AS path by summing the pCount values in
the BGPsec_Path attribute, see Section 5.) However, when a route the BGPsec_Path attribute, see Section 5.) However, when a route
server sets the pCount value to 0, it still inserts its AS number server sets the pCount value to 0, it still inserts its AS number
into the Secure_Path segment, as this information is needed to into the Secure_Path segment, as this information is needed to
validate the signature added by the route server. (See [18] for a validate the signature added by the route server. (See
discussion of setting pCount to 0 to facilitate AS Number Migration.) [I-D.ietf-sidr-as-migration] for a discussion of setting pCount to 0
BGPsec speakers SHOULD drop incoming update messages with pCount set to facilitate AS Number Migration.) BGPsec speakers SHOULD drop
to zero in cases where the BGPsec speaker does not expect its peer to incoming update messages with pCount set to zero in cases where the
set pCount to zero. (That is, pCount is only to be set to zero in BGPsec speaker does not expect its peer to set pCount to zero. (That
cases such as route servers or AS Number Migration where the BGPsec is, pCount is only to be set to zero in cases such as route servers
speaker's peer expects pCount to be set to zero.) or AS Number Migration where the BGPsec speaker's peer expects pCount
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).
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SHOULD include both of the Signature_Blocks. If the received BGPsec SHOULD 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
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 7 for a discussion of the security
ramifications of this design choice.) ramifications of this design choice.)
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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 adds a new Signature
Segment to the Signature_Block. This Signature Segment is prepended Segment to the Signature_Block. This Signature Segment is prepended
to the list of Signature Segments (placed in the first position) so to the list of Signature Segments (placed in the first position) so
that the list of Signature Segments appear in the same order as the that the list of Signature Segments appear in the same order as the
corresponding Secure_Path segments. The BGPsec speaker populates the corresponding Secure_Path segments. The BGPsec speaker populates the
fields of this new signature segment as follows. 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 [9]. the RPKI router certificate corresponding to the BGPsec speaker
This Subject Key Identifier will be used by recipients of the route [I-D.ietf-sidr-bgpsec-pki-profiles]. This Subject Key Identifier
advertisement to identify the proper certificate to use in verifying will be used by recipients of the route advertisement to identify the
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 NLRI 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 Segment Signature Segments from 1 to N as follows. Let Secure_Path
1 and Signature Segment 1 be the segments produced by the origin Segment 1 and Signature Segment 1 be the segments produced by the
AS. Let Secure_Path Segment 2 and Signature Segment 2 be the origin AS. Let Secure_Path Segment 2 and Signature Segment 2 be
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 be
the Secure_Path segment that is being added by the current AS. the Secure_Path segment that is being added by the current AS.
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 following sequence of octets to be hashed.
Sequence of Octets to be Hashed Sequence of Octets to be Hashed
+------------------------------------+
| Target AS Number | +------------------------------------+
+------------------------------------+ -\ | Target AS Number |
| Signature Segment : N-1 | \ +------------------------------------+ -\
+------------------------------------+ | | Signature Segment : N-1 | \
| Secure_Path Segment : N | | +------------------------------------+ |
+------------------------------------+ \ | Secure_Path Segment : N | |
... > For N Hops +------------------------------------+ \
+------------------------------------+ / ... > For N Hops
| Signature Segment : 1 | | +------------------------------------+ /
+------------------------------------+ | | Signature Segment : 1 | |
| Secure_Path Segment : 2 | / +------------------------------------+ |
+------------------------------------+ -/ | Secure_Path Segment : 2 | /
| Secure_Path Segment : 1 | +------------------------------------+ -/
+------------------------------------+ | Secure_Path Segment : 1 |
| Algorithm Suite Identifier | +------------------------------------+
+------------------------------------+ | Algorithm Suite Identifier |
| AFI | +------------------------------------+
+------------------------------------+ | AFI |
| SAFI | +------------------------------------+
+------------------------------------+ | SAFI |
| NLRI | +------------------------------------+
+------------------------------------+ | NLRI |
+------------------------------------+
In this sequence, the Target AS Number is the AS to whom the In this sequence, the Target AS Number is the AS to whom the
BGPsec speaker intends to send the update message. (Note that the BGPsec speaker intends to send the update message. (Note that the
Target AS number is the AS number announced by the peer in 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 Network Layer Reachability Information (NLRI) fields
are obtained from the MP_REACH_NLRI attribute. Additionally, in are obtained from the MP_REACH_NLRI attribute. Additionally, in
the Prefix field of the NLRI (from MP_REACH_NLRI), all of the the Prefix field of the NLRI (from MP_REACH_NLRI), all of the
trailing bits MUST be set to zero when constructing this trailing bits MUST be set to zero when constructing this sequence.
sequence.
o Apply to this octet sequence the digest algorithm (for the o Apply to this octet sequence the digest algorithm (for the
algorithm suite of this Signature_Block) to obtain a digest value. 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 with this digital
signature. signature.
The Signature Length field is populated with the length (in octets) The Signature Length field is populated with the length (in octets)
of the value in the Signature field. 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 [5] MUST additionally Members of autonomous system confederations [RFC5065] MUST
follow the instructions in this section for processing BGPsec update additionally follow the instructions in this section for processing
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
member sends a BGPsec update message to a peer that is a member of member sends a BGPsec update message to a peer that is a member of
the same confederation but is a different Member-AS, the the same confederation but is a different Member-AS, the
confederation member puts its (private) Member-AS Number (as opposed confederation member puts its (private) Member-AS Number (as opposed
to the public AS Confederation Identifier) in the AS Number field of to the public AS Confederation Identifier) in the AS Number field of
the Secure_Path Segment that it adds to the BGPsec update message. the Secure_Path Segment that it adds to the BGPsec update message.
Additionally, in this case, the confederation member that generates Additionally, in this case, the confederation member that generates
the Secure_Path Segment sets the Confed_Segment flag to one. This the Secure_Path Segment sets the Confed_Segment flag to one. This
means that in a BGPsec update message, an AS number appears in a means that in a BGPsec update message, an AS number appears in a
Secure_Path Segment with the Confed_Segment flag set whenever, in a Secure_Path Segment with the Confed_Segment flag set whenever, in a
non-BGPsec update message, the AS number would appear in a segment of non-BGPsec update message, the AS number would appear in a segment of
type AS_CONFED_SEQUENCE. type AS_CONFED_SEQUENCE.
Within a confederation, the verification of BGPsec signatures added Within a confederation, the verification of BGPsec signatures added
by other members of the confederation is optional. If a by other members of the confederation is optional. If a
confederation chooses not to have its members verify signatures added confederation chooses not to have its members verify signatures added
by other confederation members, then when sending a BGPsec update by other confederation members, then when sending a BGPsec update
message to a peer that is a member of the same confederation, the message to a peer that is a member of the same confederation, the
confederation members MAY set the Signature field within the confederation members MAY set the Signature field within the
Signature Segment that it generates to be zero (in lieu of Signature Segment that it generates to be zero (in lieu of
calculating the correct digital signature as described in Section calculating the correct digital signature as described in
4.2). Note that if a confederation chooses not to verify digital Section 4.2). Note that if a confederation chooses not to verify
signatures within the confederation, then BGPsec is able to provide digital signatures within the confederation, then BGPsec is able to
no assurances about the integrity of the (private) Member-AS Numbers provide no assurances about the integrity of the (private) Member-AS
placed in Secure_Path segments where the Confed_Segment flag is set Numbers placed in Secure_Path segments where the Confed_Segment flag
to one. is set to one.
When a confederation member receives a BGPsec update message from a When a confederation member receives a BGPsec update message from a
peer within the confederation and propagates it to a peer outside the peer within the confederation and propagates it to a peer outside the
confederation, it needs to remove all of the Secure_Path Segments confederation, it needs to remove all of the Secure_Path Segments
added by confederation members as well as the corresponding Signature added by confederation members as well as the corresponding Signature
Segments. To do this, the confederation member propagating the route Segments. To do this, the confederation member propagating the route
outside the confederation does the following: outside the confederation does the following:
o First, starting with the most recently added Secure_Path segment, o First, starting with the most recently added Secure_Path segment,
remove all of the consecutive Secure_Path segments that have the remove all of the consecutive Secure_Path segments that have the
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o Finally, add a Secure_Path Segment containing, in the AS field, o Finally, add a Secure_Path Segment containing, in the AS field,
the AS Confederation Identifier (the public AS number of the the AS Confederation Identifier (the public AS number of the
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 will always be the AS Confederation
Identifier (the public AS number of the confederation) as opposed to Identifier (the public AS number of the confederation) as opposed to
the Member-AS Number. 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
skipping to change at page 18, line 21 skipping to change at page 19, line 6
in the corresponding Secure_Path segment is set to one. If the 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_Sequence 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_Sequence 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 error in the BGPsec_Path
attribute MUST be handled using the "treat-as-withdraw", approach as attribute MUST be handled using the "treat-as-withdraw", approach as
defined in RFC7606 [11].) 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. However, BGPsec update messages do not contain the AS_PATH attribute.
the AS_PATH attribute can be reconstructed from the BGPsec_Path However, the AS_PATH attribute can be reconstructed from the
attribute. This is necessary in the case where a route advertisement BGPsec_Path attribute. This is necessary in the case where a route
is received via a BGPsec update message and then propagated to a peer advertisement is received via a BGPsec update message and then
via a non-BGPsec update message (e.g., because the latter peer does propagated to a peer via a non-BGPsec update message (e.g., because
not support BGPsec). Note that there may be additional cases where an the latter peer does not support BGPsec). Note that there may be
implementation finds it useful to perform this reconstruction. Before additional cases where an implementation finds it useful to perform
attempting to reconstruct an AS_PATH for the purpose of forwarding an this reconstruction. Before attempting to reconstruct an AS_PATH for
unsigned (non-BGPsec) update to a peer, a BGPsec speaker MUST perform the purpose of forwarding an unsigned (non-BGPsec) update to a peer,
the basic integrity checks listed in Section 5.2 to ensure that the a BGPsec speaker MUST perform the basic integrity checks listed in
received BGPsec update is properly formed. Section 5.2 to ensure that the received BGPsec update is properly
formed.
The AS_PATH attribute can be constructed from the BGPsec_Path The AS_PATH attribute can be constructed from the BGPsec_Path
attribute as follows. Starting with an empty AS_PATH attribute, attribute as follows. Starting with an empty AS_PATH attribute,
process the Secure_Path segments in order from least-recently added process the Secure_Path segments in order from least-recently added
(corresponding to the origin) to most-recently added. For each (corresponding to the origin) to most-recently added. For each
Secure_Path segment perform the following steps: Secure_Path segment perform the following steps:
1. If the Confed_Segment flag in the Secure_Path segment is set to 1. If the Confed_Segment flag in the Secure_Path segment is set to
one, then look at the most-recently added segment in the AS_PATH. one, then look at the most-recently added segment in the AS_PATH.
skipping to change at page 19, line 44 skipping to change at page 20, line 31
AS_PATH is of type AS_SEQUENCE then add (prepend to the AS_PATH is of type AS_SEQUENCE then add (prepend to the
segment) a number of elements equal to the pCount field in the segment) a number of elements equal to the pCount field in the
current Secure_Path segment. The value of each of these current Secure_Path segment. The value of each of these
elements shall be the AS number contained in the current elements shall be the AS number contained in the current
Secure_Path segment. (That is, if the pCount field is X, then Secure_Path segment. (That is, if the pCount field is X, then
add X copies of the Secure_Path segment's AS Number field to add X copies of the Secure_Path segment's AS Number field to
the existing AS_SEQUENCE.) the existing AS_SEQUENCE.)
As part of the above described procedure, the following additional As part of the above described procedure, the following additional
actions are performed in order not to exceed the size limitations of actions are performed in order not to exceed the size limitations of
AS_SEQUENCE and AS_CONFED_SEQUENCE. While adding the next Secure_Path AS_SEQUENCE and AS_CONFED_SEQUENCE. While adding the next
segment (with its prepends, if any) to the AS_PATH being assembled, Secure_Path segment (with its prepends, if any) to the AS_PATH being
if it would cause the AS_SEQUENCE (or AS_CONFED_SEQUENCE) at hand to assembled, if it would cause the AS_SEQUENCE (or AS_CONFED_SEQUENCE)
exceed the 255 ASN per segment limit [2][5], then the BGPsec speaker at hand to exceed the 255 ASN per segment limit [RFC4271][RFC5065],
would follow the recommendations in RFC4271 [2] and RFC5065 [5] of then the BGPsec speaker would follow the recommendations in RFC 4271
creating another segment of the same type (AS_SEQUENCE or [RFC4271] and RFC 5065 [RFC5065] of creating another segment of the
AS_CONFED_SEQUENCE) and continue filling that. same type (AS_SEQUENCE or AS_CONFED_SEQUENCE) and continue filling
that.
5. Processing a Received BGPsec Update 5. Processing a Received BGPsec Update
Upon receiving a BGPsec update message from an external (eBGP) peer, Upon receiving a BGPsec update message from an external (eBGP) peer,
a BGPsec speaker SHOULD validate the message to determine the a BGPsec speaker SHOULD validate the message to determine the
authenticity of the path information contained in the BGPsec_Path authenticity of the path information contained in the BGPsec_Path
attribute. Typically, a BGPsec speaker will also wish to perform attribute. Typically, a BGPsec speaker will also wish to perform
origin validation (see [19] and [20]) on an incoming BGPsec update origin validation (see RFC 6483 [RFC6483] and RFC 6811 [RFC6811]) on
message, but such validation is independent of the validation an incoming BGPsec update message, but such validation is independent
described in this section. of the validation described in this section.
Section 5.1 provides an overview of BGPsec validation and Section 5.2 Section 5.1 provides an overview of BGPsec validation and Section 5.2
provides a specific algorithm for performing such validation. (Note provides a specific algorithm for performing such validation. (Note
that an implementation need not follow the specific algorithm in that an implementation need not follow the specific algorithm in
Section 5.2 as long as the input/output behavior of the validation is Section 5.2 as long as the input/output behavior of the validation is
identical to that of the algorithm in Section 5.2.) During identical to that of the algorithm in Section 5.2.) During
exceptional conditions (e.g., the BGPsec speaker receives an exceptional conditions (e.g., the BGPsec speaker receives an
incredibly large number of update messages at once) a BGPsec speaker incredibly large number of update messages at once) a BGPsec speaker
MAY temporarily defer validation of incoming BGPsec update messages. MAY temporarily defer validation of incoming BGPsec update messages.
The treatment of such BGPsec update messages, whose validation has The treatment of such BGPsec update messages, whose validation has
been deferred, is a matter of local policy. However, an been deferred, is a matter of local policy. However, an
implementation SHOULD ensure that deferment of validation and status implementation SHOULD ensure that deferment of validation and status
of deferred messages is visible to the operator. of deferred messages is visible to the operator.
The validity of BGPsec update messages is a function of the current The validity of BGPsec update messages is a function of the current
RPKI state. When a BGPsec speaker learns that RPKI state has changed RPKI state. When a BGPsec speaker learns that RPKI state has changed
(e.g., from an RPKI validating cache via the RPKI-to-Router protocol (e.g., from an RPKI validating cache via the RPKI-to-Router protocol
[15]), the BGPsec speaker MUST re-run validation on all affected [I-D.ietf-sidr-rpki-rtr-rfc6810-bis]), the BGPsec speaker MUST re-run
update messages stored in its Adj-RIB-In. For example, when a given validation on all affected update messages stored in its Adj-RIB-In.
RPKI certificate ceases to be valid (e.g., it expires or is revoked), For example, when a given RPKI certificate ceases to be valid (e.g.,
all update messages containing a signature whose SKI matches the SKI it expires or is revoked), all update messages containing a signature
in the given certificate must be re-assessed to determine if they are whose SKI matches the SKI in the given certificate must be re-
still valid. If this reassessment determines that the validity state assessed to determine if they are still valid. If this reassessment
of an update has changed then, depending on local policy, it may be determines that the validity state of an update has changed then,
necessary to re-run best path selection. depending on local policy, it may be necessary to re-run best path
selection.
BGPsec update messages do not contain an AS_PATH attribute. BGPsec update messages do not contain an AS_PATH attribute.
Therefore, a BGPsec speaker MUST utilize the AS path information in Therefore, a BGPsec speaker MUST utilize the AS path information in
the BGPsec_Path attribute in all cases where it would otherwise use the BGPsec_Path attribute in all cases where it would otherwise use
the AS path information in the AS_PATH attribute. The only exception the AS path information in the AS_PATH attribute. The only exception
to this rule is when AS path information must be updated in order to to this rule is when AS path information must be updated in order to
propagate a route to a peer (in which case the BGPsec speaker follows propagate a route to a peer (in which case the BGPsec speaker follows
the instructions in Section 4). Section 4.4 provides an algorithm the instructions in Section 4). Section 4.4 provides an algorithm
for constructing an AS_PATH attribute from a BGPsec_Path attribute. for constructing an AS_PATH attribute from a BGPsec_Path attribute.
Whenever the use of AS path information is called for (e.g., loop Whenever the use of AS path information is called for (e.g., loop
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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 [16] for the RPKI-to- the BGPsec speaker using the router key PDU
Router protocol [15].) [I-D.ietf-sidr-rtr-keying] for the RPKI-to-Router protocol
[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, we expect some operators will choose to
treat BGPsec validation status differently for update messages treat BGPsec validation status differently for update messages
received over different BGP sessions.) 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. However, BGPsec
specifies no changes to the BGP decision process. (See [17] for specifies no changes to the BGP decision process. (See
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
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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 none of the Secure_Path segments contain a Flags field with
the Confed_Sequence flag set to one. the Confed_Sequence flag set to one.
5. If the update message was received from a peer that is not 5. 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 RFC7606 [11]. BGPsec speakers MUST handle these errors handled as per RFC 7606 [RFC7606]. BGPsec speakers MUST handle these
using the "treat-as-withdraw" approach as defined in RFC7606 [11]. errors using the "treat-as-withdraw" approach as defined in RFC 7606
[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 the BGPsec speaker MUST treat the update message in the same
manner that the BGPsec speaker would treat an (unsigned) update manner that the BGPsec speaker would treat an (unsigned) update
message that arrived without a BGPsec_Path attribute. message that arrived without a BGPsec_Path attribute.
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 0): For clarity, let us number the Secure_Path and
corresponding Signature Segments from 1 to N as follows. Let corresponding Signature Segments from 1 to N as follows. Let
Secure_Path Segment 1 and Signature Segment 1 be the segments Secure_Path Segment 1 and Signature Segment 1 be the segments
produced by the origin AS. Let Secure_Path Segment 2 and Signature produced by the origin AS. Let Secure_Path Segment 2 and
Segment 2 be the segments added by the next AS after the origin. Signature Segment 2 be the segments added by the next AS after the
Continue this method of numbering and ultimately let Signature origin. Continue this method of numbering and ultimately let
Segment N be the Signature Segment that is currently being Signature Segment N be the Signature Segment that is currently
verified and let Secure_Path Segment N be the corresponding being verified and let Secure_Path Segment N be the corresponding
Secure_Path Segment. Secure_Path Segment.
o (Step I): Locate the public key needed to verify the signature (in o (Step I): 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 II): 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 following sequence of octets to be hashed.
Sequence of Octets to be Hashed Sequence of Octets to be Hashed for Signature Verification
+------------------------------------+
| Target AS Number | +------------------------------------+
+------------------------------------+ -\ | Target AS Number |
| Signature Segment : N-1 | \ +------------------------------------+ -\
+------------------------------------+ | | Signature Segment : N-1 | \
| Secure_Path Segment : N | | +------------------------------------+ |
+------------------------------------+ \ | Secure_Path Segment : N | |
... > For N Hops +------------------------------------+ \
+------------------------------------+ / ... > For N Hops
| Signature Segment : 1 | | +------------------------------------+ /
+------------------------------------+ | | Signature Segment : 1 | |
| Secure_Path Segment : 2 | / +------------------------------------+ |
+------------------------------------+ -/ | Secure_Path Segment : 2 | /
| Secure_Path Segment : 1 | +------------------------------------+ -/
+------------------------------------+ | Secure_Path Segment : 1 |
| Algorithm Suite Identifier | +------------------------------------+
+------------------------------------+ | Algorithm Suite Identifier |
| AFI | +------------------------------------+
+------------------------------------+ | AFI |
| SAFI | +------------------------------------+
+------------------------------------+ | SAFI |
| NLRI | +------------------------------------+
+------------------------------------+ | NLRI |
+------------------------------------+
For the first segment to be processed (the most recently added For the first segment to be processed (the most recently added
segment), the 'Target AS Number' is the AS number of the BGPsec segment), the 'Target AS Number' is the AS number of the BGPsec
speaker validating the update message. Note that if a BGPsec speaker validating the update message. Note that if a BGPsec
speaker uses multiple AS Numbers (e.g., the BGPsec speaker is a speaker uses multiple AS Numbers (e.g., the BGPsec speaker is a
member of a confederation), the AS number used here MUST be the AS member of a confederation), the AS number used here MUST be the AS
number announced in the OPEN message for the BGP session over number announced in the OPEN message for the BGP session over
which the BGPsec update was received. which the BGPsec update was received.
For each other Signature Segment, the 'Target AS Number' is the AS For each other Signature Segment, the 'Target AS Number' is the AS
number in the Secure_Path segment that corresponds to the number in the Secure_Path segment that corresponds to the
Signature Segment added immediately after the one being processed. Signature Segment added immediately after the one being processed.
(That is, in the Secure_Path segment that corresponds to the (That is, in the Secure_Path segment that corresponds to the
Signature segment that the validator just finished processing.) 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 Network Layer
Reachability Information (NLRI) fields are obtained from the Reachability Information (NLRI) fields are obtained from the
MP_REACH_NLRI attribute. Additionally, in the Prefix field of the MP_REACH_NLRI attribute. Additionally, in the Prefix field of the
NLRI (from MP_REACH_NLRI), all of the trailing bits MUST be set to NLRI (from MP_REACH_NLRI), all of the trailing bits MUST be set to
zero when constructing this sequence. zero when constructing this sequence.
o (Step III): Use the signature validation algorithm (for the given o (Step III): 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 II 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 I above.
If the signature validation algorithm determines that the If the signature validation algorithm determines that the
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two Signature_Blocks then the update message is deemed 'Valid' if the two Signature_Blocks then the update message is deemed 'Valid' if the
first Signature_Block is marked 'Valid' OR the second Signature_Block first Signature_Block is marked 'Valid' OR the second Signature_Block
is marked 'Valid'.) is marked 'Valid'.)
6. Algorithms and Extensibility 6. Algorithms and Extensibility
6.1. Algorithm Suite Considerations 6.1. Algorithm Suite Considerations
Note that there is currently no support for bilateral negotiation Note that there is currently no support for bilateral negotiation
(using BGP capabilities) between BGPsec peers to use a particular (using BGP capabilities) between BGPsec peers to use a particular
(digest and signature) algorithm suite. This is because the algorithm (digest and signature) algorithm suite. This is because the
suite used by the sender of a BGPsec update message must be algorithm suite used by the sender of a BGPsec update message must be
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 [10]. BGPsec speakers [I-D.ietf-sidr-bgpsec-algs].
We anticipate that, in the future, the mandatory algorithm suites We anticipate 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 Sections 3 and 4 specify and the 'new' algorithm suite. (Note that Section 3 and Section 4
how the BGPsec_Path attribute can contain signatures, in parallel, specify how the BGPsec_Path attribute can contain signatures, in
for two algorithm suites.) Once the transition is complete, use of parallel, for two algorithm suites.) Once the transition is
the old 'current' algorithm will be deprecated, use of the 'new' complete, use of the old 'current' algorithm will be deprecated, use
algorithm will be mandatory, and a subsequent 'even newer' algorithm of the 'new' algorithm will be mandatory, and a subsequent 'even
suite may be specified as recommended to implement. Once the newer' algorithm suite may be specified as recommended to implement.
transition has successfully been completed in this manner, BGPsec Once the transition has successfully been completed in this manner,
speakers SHOULD include only a single Signature_Block (corresponding BGPsec speakers SHOULD include only a single Signature_Block
to the 'new' algorithm). (corresponding to the 'new' algorithm).
6.2. Extensibility Considerations 6.2. Extensibility Considerations
This section discusses potential changes to BGPsec that would require This section discusses potential changes to BGPsec that would require
substantial changes to the processing of the BGPsec_Path and thus substantial changes to the processing of the BGPsec_Path and thus
necessitate a new version of BGPsec. Examples of such changes necessitate a new version of BGPsec. Examples of such changes
include: include:
o A new type of signature algorithm that produces signatures of o A new type of signature algorithm that produces signatures of
variable length variable length
skipping to change at page 27, line 20 skipping to change at page 28, line 10
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. 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 [14]. considerations, please see RFC 7132 [RFC7132].
7.1 Security Guarantees 7.1. Security Guarantees
When used in conjunction with Origin Validation (see [19] and [20]), When used in conjunction with Origin Validation (see RFC 6483
a BGPsec speaker who receives a valid BGPsec update message, [RFC6483] and RFC 6811 [RFC6811]), a BGPsec speaker who receives a
containing a route advertisement for a given prefix, is provided with valid BGPsec update message, containing a route advertisement for a
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.
o For each AS in the path, a BGPsec speaker authorized by the holder o For each AS in the path, a BGPsec speaker authorized by the holder
of the AS number intentionally chose (in accordance with local of the AS number intentionally chose (in accordance with local
policy) to propagate the route advertisement to the subsequent AS policy) to propagate the route advertisement to the subsequent AS
in the path. in the path.
That is, the recipient of a valid BGPsec update message is assured That is, the recipient of a valid BGPsec update message is assured
that the update propagated via the sequence of ASes listed in the that the update propagated via the sequence of ASes listed in the
Secure_Path portion of the BGPsec_Path attribute. (It should be noted Secure_Path portion of the BGPsec_Path attribute. (It should be
that BGPsec does not offer any guarantee that the data packets would noted that BGPsec does not offer any guarantee that the data packets
flow along the indicated path; it only guarantees that the BGP update would flow along the indicated path; it only guarantees that the BGP
conveying the path indeed propagated along the indicated path.) update conveying the path indeed propagated along the indicated
Furthermore, the recipient is assured that this path terminates in an path.) Furthermore, the recipient is assured that this path
autonomous system that has been authorized by the IP address space terminates in an autonomous system that has been authorized by the IP
holder as a legitimate destination for traffic to the given prefix. address space holder as a legitimate destination for traffic to the
given prefix.
Note that although BGPsec provides a mechanism for an AS to validate Note that although BGPsec provides a mechanism for an AS to validate
that a received update message has certain security properties, the that a received update message has certain security properties, the
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 7.2. 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. Thus the BGPsec speaker
creates a signature using both algorithm suites and creates a new creates a signature using both algorithm suites and creates a new
update message that contains both the 'Valid' and the 'Not Valid' set update message that contains both the 'Valid' and the 'Not Valid' set
of signatures (from its own vantage point). 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 case
where the BGPsec speaker receives an update message with both a set where the BGPsec speaker receives an update message with both a set
of algorithm A signatures which are 'Valid' and a set of algorithm B of algorithm A signatures which are 'Valid' and a set of algorithm B
signatures which are 'Not Valid'. In such a case it is possible signatures which are 'Not Valid'. In such a case it is possible
(perhaps even likely, depending on the state of the algorithm (perhaps even likely, depending on the state of the algorithm
transition) that some of the BGPsec speaker's peers (or other transition) that some of the BGPsec speaker's peers (or other
entities further 'downstream' in the BGP topology) do not support entities further 'downstream' in the BGP topology) do not support
algorithm A. Therefore, if the BGPsec speaker were to remove the 'Not algorithm A. Therefore, if the BGPsec speaker were to remove the
Valid' set of signatures corresponding to algorithm B, such entities 'Not Valid' set of signatures corresponding to algorithm B, such
would treat the message as though it were unsigned. By including the entities would treat the message as though it were unsigned. By
'Not Valid' set of signatures when propagating a route advertisement, including the 'Not Valid' set of signatures when propagating a route
the BGPsec speaker ensures that 'downstream' entities have as much advertisement, the BGPsec speaker ensures that 'downstream' entities
information as possible to make an informed opinion about the have as much information as possible to make an informed opinion
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'
signatures the BGPsec speaker might actually cause a downstream signatures the BGPsec speaker might actually cause a downstream
entity to 'upgrade' the status of a route advertisement from 'Not entity to 'upgrade' the status of a route advertisement from 'Not
Valid' to unsigned. Finally, note that in the above scenario, the Valid' to unsigned. Finally, note that in the above scenario, the
BGPsec speaker might have deemed algorithm A signatures 'Valid' only BGPsec speaker might have deemed algorithm A signatures 'Valid' only
because of some issue with RPKI state local to its AS (for example, because of some issue with RPKI state local to its AS (for example,
its AS might not yet have obtained a CRL indicating that a key used its AS might not yet have obtained a CRL indicating that a key used
to verify an algorithm A signature belongs to a newly revoked to verify an algorithm A signature belongs to a newly revoked
certificate). In such a case, it is highly desirable for a certificate). In such a case, it is highly desirable for a
downstream entity to treat the update as 'Not Valid' (due to the downstream entity to treat the update as 'Not Valid' (due to the
revocation) and not as 'unsigned' (which would happen if the 'Not revocation) and not as 'unsigned' (which would happen if the 'Not
Valid' Signature_Blocks were removed). Valid' Signature_Blocks were removed).
A similar argument applies to the case where a BGPsec speaker (for A similar argument applies to the case where a BGPsec speaker (for
some reason such as lack of viable alternatives) selects as its best some reason such as lack of viable alternatives) selects as its best
path (to a given prefix) a route obtained via a 'Not Valid' BGPsec path (to a given prefix) a route obtained via a 'Not Valid' BGPsec
update message. In such a case, the BGPsec speaker should propagate a update message. In such a case, the BGPsec speaker should propagate
signed BGPsec update message, adding its signature to the 'Not Valid' a signed BGPsec update message, adding its signature to the 'Not
signatures that already exist. Again, this is to ensure that Valid' signatures that already exist. Again, this is to ensure that
'downstream' entities are able to make an informed decision and not 'downstream' entities are able to make an informed decision and not
erroneously treat the route as unsigned. It should also be noted erroneously treat the route as unsigned. It should also be noted
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 NLRI 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'.
7.3 Mitigation of Denial of Service Attacks 7.3. 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. Here we consider
the mitigation only of denial of service attacks that are specific to the mitigation only of denial of service attacks that are specific to
BGPsec. BGPsec.
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
denial of service protection for all implementations. denial of service protection for all implementations.
Additionally, sending update messages with very long AS paths (and Additionally, sending update messages with very long AS paths (and
hence a large number of signatures) is a potential mechanism to hence a large number of signatures) is a potential mechanism to
conduct denial of service attacks. For this reason, it is important conduct denial of service attacks. For this reason, it is important
that an implementation of the validation algorithm stops attempting that an implementation of the validation algorithm stops attempting
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 mitigate denial of service attacks.) Furthermore, implementations can
such attacks by only performing validation on update messages that, mitigate such attacks by only performing validation on update
if valid, would be selected as the best path. That is, if an update messages that, if valid, would be selected as the best path. That
message contains a route that would lose out in best path selection is, if an update message contains a route that would lose out in best
for other reasons (e.g., a very long AS path) then it is not path selection for other reasons (e.g., a very long AS path) then it
necessary to determine the BGPsec-validity status of the route. is not necessary to determine the BGPsec-validity status of the
route.
7.4 Additional Security Considerations 7.4. 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 effective length of the
AS-PATH. However, entities other than route servers could AS-PATH. However, entities other than route servers could
conceivably use this mechanism (set the pCount to zero) to attract conceivably use this mechanism (set the pCount to zero) to attract
traffic (by reducing the effective length of the AS-PATH) traffic (by reducing the effective length of the AS-PATH)
illegitimately. This risk is largely mitigated if every BGPsec illegitimately. This risk is largely mitigated if every BGPsec
speaker drops incoming update messages that set pCount to zero but speaker drops incoming update messages that set pCount to zero but
come from a peer that is not a route server. However, note that a come from a peer that is not a route server. However, note that a
skipping to change at page 30, line 40 skipping to change at page 31, line 31
two or more hops away has set pCount to zero is unable to verify for two or more hops away has set pCount to zero is unable to verify for
themselves whether pCount was set to zero legitimately. themselves whether pCount was set to zero legitimately.
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.
8. IANA Considerations 8. IANA Considerations
This document registers a new capability in the registry of BGP This document registers a new capability in the registry of BGP
Capabilities. The description for the new capability is "BGPsec Capabilities. The description for the new capability is "BGPsec
Capability". The reference for the new capability is this document Capability". The reference for the new capability is this document
(i.e., the RFC that replaces draft-ietf-sidr-bgpsec-protocol), see (i.e., the RFC that replaces draft-ietf-sidr-bgpsec-protocol), see
Section 2.1. Section 2.1.
This document registers a new path attribute in the registry of BGP This document registers a new path attribute in the registry of BGP
Path Attributes. The code for this new attribute is "BGPsec_Path". Path Attributes. The code for this new attribute is "BGPsec_Path".
The reference for the new capability is this document (i.e., the RFC The reference for the new capability is this document (i.e., the RFC
that replaces draft-ietf-sidr-bgpsec-protocol), see Section 3. that replaces draft-ietf-sidr-bgpsec-protocol), see Section 3.
This document does not create any new IANA registries. This document does not create any new IANA registries.
9. Contributors 9. Contributors
9.1. Authors 9.1. Authors
Rob Austein Rob Austein
skipping to change at page 32, line 16 skipping to change at page 33, line 14
9.2. Acknowledgements 9.2. Acknowledgements
The authors would like to thank Michael Baer, Luke Berndt, Oliver The authors would like to thank Michael Baer, Luke Berndt, Oliver
Borchert, Wes George, Jeff Haas, Sharon Goldberg, Ed Kern, David Borchert, Wes George, Jeff Haas, Sharon Goldberg, Ed Kern, David
Mandelberg, Doug Maughan, Pradosh Mohapatra, Chris Morrow, Russ Mandelberg, Doug Maughan, Pradosh Mohapatra, Chris Morrow, Russ
Mundy, Sandy Murphy, Keyur Patel, Mark Reynolds, Heather Schiller, Mundy, Sandy Murphy, Keyur Patel, Mark Reynolds, Heather Schiller,
Jason Schiller, John Scudder, Ruediger Volk and David Ward for their Jason Schiller, John Scudder, Ruediger Volk and David Ward for their
valuable input and review. valuable input and review.
10. Normative References 10. References
[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement 10.1. Normative References
Levels", BCP 14, RFC 2119, March 1997.
[2] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A Border
Gateway Protocol 4", RFC 4271, January 2006.
[3] Bates, T., Chandra, R., Katz, D., and Y. Rekhter, [I-D.ietf-idr-bgp-extended-messages]
"Multiprotocol Extensions for BGP-4", RFC 4760, January 2007. Bush, R., Patel, K., and D. Ward, "Extended Message
support for BGP", draft-ietf-idr-bgp-extended-messages-13
(work in progress), June 2016.
[4] Vohra, Q. and E. Chen, "BGP Support for Four-Octet AS Number [I-D.ietf-sidr-bgpsec-algs]
Space", RFC 6793, December 2012. Turner, S., "BGPsec Algorithms, Key Formats, & Signature
Formats", draft-ietf-sidr-bgpsec-algs-15 (work in
progress), April 2016.
[5] Traina, P., McPherson, D., and J. Scudder, "Autonomous System [I-D.ietf-sidr-bgpsec-pki-profiles]
Confederations for BGP", RFC 5065, August 2007. Reynolds, M., Turner, S., and D. Kent, "A Profile for
BGPsec Router Certificates, Certificate Revocation Lists,
and Certification Requests", draft-ietf-sidr-bgpsec-pki-
profiles-18 (work in progress), July 2016.
[6] Scudder, J. and R. Chandra, "Capabilities Advertisement with [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
BGP-4", RFC 5492, February 2009. Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[7] Lepinski, M., Kent, S., and D. Kong, "A Profile for Route [RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
Origin Authorizations (ROAs)", RFC 6482, February 2012. Border Gateway Protocol 4 (BGP-4)", RFC 4271,
DOI 10.17487/RFC4271, January 2006,
<http://www.rfc-editor.org/info/rfc4271>.
[8] Patel, K., Ward, D., and R. Bush, "Extended Message support for [RFC4760] Bates, T., Chandra, R., Katz, D., and Y. Rekhter,
BGP", draft-ietf-idr-bgp-extended-messages (work in progress), "Multiprotocol Extensions for BGP-4", RFC 4760,
May 2016. DOI 10.17487/RFC4760, January 2007,
<http://www.rfc-editor.org/info/rfc4760>.
[9] Reynolds, M., Turner, S., and S. Kent, "A Profile for BGPsec [RFC5065] Traina, P., McPherson, D., and J. Scudder, "Autonomous
Router Certificates, Certificate Revocation Lists, and System Confederations for BGP", RFC 5065,
Certification Requests", draft-ietf-sidr-bgpsec-pki-profiles DOI 10.17487/RFC5065, August 2007,
(work in progress), June 2016. <http://www.rfc-editor.org/info/rfc5065>.
[10] Turner, S., "BGP Algorithms, Key Formats, & Signature Formats", [RFC5492] Scudder, J. and R. Chandra, "Capabilities Advertisement
draft-ietf-sidr-bgpsec-algs (work in progress), April 2016. with BGP-4", RFC 5492, DOI 10.17487/RFC5492, February
2009, <http://www.rfc-editor.org/info/rfc5492>.
[11] Chen, E., Scudder, J., Mohapatra, P., and K. Patel, "Revised [RFC6482] Lepinski, M., Kent, S., and D. Kong, "A Profile for Route
Error Handling for BGP UPDATE Messages", RFC 7606, August 2015. Origin Authorizations (ROAs)", RFC 6482,
DOI 10.17487/RFC6482, February 2012,
<http://www.rfc-editor.org/info/rfc6482>.
11. Informative References [RFC6793] Vohra, Q. and E. Chen, "BGP Support for Four-Octet
Autonomous System (AS) Number Space", RFC 6793,
DOI 10.17487/RFC6793, December 2012,
<http://www.rfc-editor.org/info/rfc6793>.
[12] Lepinski, M. and S. Kent, "An Infrastructure to Support Secure [RFC7606] Chen, E., Ed., Scudder, J., Ed., Mohapatra, P., and K.
Internet Routing", RFC 6480, February 2012. Patel, "Revised Error Handling for BGP UPDATE Messages",
RFC 7606, DOI 10.17487/RFC7606, August 2015,
<http://www.rfc-editor.org/info/rfc7606>.
[13] Kumari, W. and K. Sriram, "Recommendation for Not Using AS_SET 10.2. Informative References
and AS_CONFED_SET in BGP", RFC 6472, December 2011.
[14] Kent, S. and A. Chi, "Threat Model for BGP Path Security", RFC [I-D.ietf-sidr-as-migration]
7132, February 2014. George, W. and S. Murphy, "BGPSec Considerations for AS
Migration", draft-ietf-sidr-as-migration-05 (work in
progress), April 2016.
[15] Bush, R. and R. Austein, "The Resource Public Key [I-D.ietf-sidr-bgpsec-ops]
Infrastructure (RPKI) to Router Protocol", draft-ietf-sidr- Bush, R., "BGPsec Operational Considerations", draft-ietf-
rpki-rtr-rfc6810-bis (work in progress), March 2016. sidr-bgpsec-ops-10 (work in progress), June 2016.
[16] Bush, R., Turner, S., and K. Patel, "Router Keying for BGPsec", [I-D.ietf-sidr-rpki-rtr-rfc6810-bis]
draft-ietf-sidr-rtr-keying (work in progress), June 2016. Bush, R. and R. Austein, "The Resource Public Key
Infrastructure (RPKI) to Router Protocol", draft-ietf-
sidr-rpki-rtr-rfc6810-bis-07 (work in progress), March
2016.
[17] Bush, R., "BGPsec Operational Considerations", draft-ietf-sidr- [I-D.ietf-sidr-rtr-keying]
bgpsec-ops (work in progress), June 2016. Bush, R., Turner, S., and K. Patel, "Router Keying for
BGPsec", draft-ietf-sidr-rtr-keying-12 (work in progress),
June 2016.
[18] George, W. and S. Murphy, "BGPsec Considerations for AS [RFC6472] Kumari, W. and K. Sriram, "Recommendation for Not Using
Migration", draft-ietf-sidr-as-migration (work in progress), AS_SET and AS_CONFED_SET in BGP", BCP 172, RFC 6472,
April 2016. DOI 10.17487/RFC6472, December 2011,
<http://www.rfc-editor.org/info/rfc6472>.
[19] Huston, G. and G. Michaelson, "Validation of Route Origination [RFC6480] Lepinski, M. and S. Kent, "An Infrastructure to Support
Using the Resource Certificate Public Key Infrastructure (PKI) Secure Internet Routing", RFC 6480, DOI 10.17487/RFC6480,
and Route Origin Authorizations (ROAs)", RFC 6483, February February 2012, <http://www.rfc-editor.org/info/rfc6480>.
2013.
[20] Mohapatra, P., Scudder, J., Ward, D., Bush, R., and R. Austein, [RFC6483] Huston, G. and G. Michaelson, "Validation of Route
"BGP Prefix Origin Validation", RFC 6811, January 2013. Origination Using the Resource Certificate Public Key
Infrastructure (PKI) and Route Origin Authorizations
(ROAs)", RFC 6483, DOI 10.17487/RFC6483, February 2012,
<http://www.rfc-editor.org/info/rfc6483>.
Author's Address [RFC6811] Mohapatra, P., Scudder, J., Ward, D., Bush, R., and R.
Austein, "BGP Prefix Origin Validation", RFC 6811,
DOI 10.17487/RFC6811, January 2013,
<http://www.rfc-editor.org/info/rfc6811>.
[RFC7132] Kent, S. and A. Chi, "Threat Model for BGP Path Security",
RFC 7132, DOI 10.17487/RFC7132, February 2014,
<http://www.rfc-editor.org/info/rfc7132>.
Authors' Addresses
Matthew Lepinski (editor) Matthew Lepinski (editor)
New College of Florida NCF
5800 Bay Shore Road 5800 Bay Shore Road
Sarasota, FL 34243 Sarasota FL 34243
USA USA
Email: mlepinski@ncf.edu Email: mlepinski@ncf.edu
Kotikalapudi Sriram (editor) Kotikalapudi Sriram (editor)
National Institute of Standards and Technology NIST
100 Bureau Drive 100 Bureau Drive
Gaithersburg, MD 20899 Gaithersburg MD 20899
USA USA
Email: kotikalapudi.sriram@nist.gov Email: kotikalapudi.sriram@nist.gov
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