draft-ietf-sidr-rtr-keying-12.txt   draft-ietf-sidr-rtr-keying-13.txt 
Network Working Group R. Bush Network Working Group R. Bush
Internet-Draft IIJ Lab / Dragon Research Lab Internet-Draft IIJ Lab / Dragon Research Lab
Intended status: Standards Track S. Turner Intended status: Standards Track S. Turner
Expires: December 17, 2016 IECA, Inc. Expires: October 7, 2017 sn3rd
K. Patel K. Patel
Cisco Systems Arrcus, Inc.
June 15, 2016 April 5, 2017
Router Keying for BGPsec Router Keying for BGPsec
draft-ietf-sidr-rtr-keying-12 draft-ietf-sidr-rtr-keying-13
Abstract Abstract
BGPsec-speaking routers are provisioned with private keys in order to BGPsec-speaking routers are provisioned with private keys in order to
sign BGPsec announcements. The corresponding public keys are sign BGPsec announcements. The corresponding public keys are
published in the global Resource Public Key Infrastructure, enabling published in the global Resource Public Key Infrastructure, enabling
verification of BGPsec messages. This document describes two methods verification of BGPsec messages. This document describes two methods
of generating the public-private key-pairs: router-driven and of generating the public-private key-pairs: router-driven and
operator-driven. operator-driven.
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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This Internet-Draft will expire on May 5, 2016. This Internet-Draft will expire on January 16, 2017.
Copyright Notice Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the Copyright (c) 2017 IETF Trust and the persons identified as the
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Table of Contents Table of Contents
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Management / Router Communication . . . . . . . . . . . . . . 4 2. Management / Router Communication . . . . . . . . . . . . . . 3
3. Exchanging Certificates . . . . . . . . . . . . . . . . . . . 4 3. Exchanging Certificates . . . . . . . . . . . . . . . . . . . 4
4. Set-Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 4. Set-Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
5. PKCS#10 Generation . . . . . . . . . . . . . . . . . . . . . . 4 5. PKCS#10 Generation . . . . . . . . . . . . . . . . . . . . . . 4
5.1. Router-Generated Keys . . . . . . . . . . . . . . . . . . 5 5.1. Router-Generated Keys . . . . . . . . . . . . . . . . . . 4
5.2. Operator-Generated Keys . . . . . . . . . . . . . . . . . 5 5.2. Operator-Generated Keys . . . . . . . . . . . . . . . . . 5
6. Installing Signed Keys . . . . . . . . . . . . . . . . . . . . 5 6. Installing Certified Keys . . . . . . . . . . . . . . . . . . 5
7. Key Management . . . . . . . . . . . . . . . . . . . . . . . . 7 7. Advanced Deployment Scenarios . . . . . . . . . . . . . . . . 6
7.1. Key Validity . . . . . . . . . . . . . . . . . . . . . . . 7 8. Key Management . . . . . . . . . . . . . . . . . . . . . . . . 7
7.2. Key Roll-Over . . . . . . . . . . . . . . . . . . . . . . 7 8.1. Key Validity . . . . . . . . . . . . . . . . . . . . . . . 8
7.3. Key Revocation . . . . . . . . . . . . . . . . . . . . . . 8 8.2. Key Roll-Over . . . . . . . . . . . . . . . . . . . . . . 8
7.4. Router Replacement . . . . . . . . . . . . . . . . . . . . 9 7.3. Key Revocation . . . . . . . . . . . . . . . . . . . . . . 9
8. Security Considerations . . . . . . . . . . . . . . . . . . . 9 8.4. Router Replacement . . . . . . . . . . . . . . . . . . . . 9
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 9. Security Considerations . . . . . . . . . . . . . . . . . . . 10
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 10 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
10.1. Normative References . . . . . . . . . . . . . . . . . . 10 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 11
10.2. Informative References . . . . . . . . . . . . . . . . . 11 11.1. Normative References . . . . . . . . . . . . . . . . . . 11
Appendix A. Management/Router Channel Security . . . . . . . . . 12 11.1. Informative References . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 13 Appendix A. Management/Router Channel Security . . . . . . . . . 14
Appendix B. The n00b Guide to BGPsec Key Management . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 17
1. Introduction 1. Introduction
BGPsec-speaking routers are provisioned with private keys, which BGPsec-speaking routers are provisioned with private keys, which
allow them to digitally sign BGPsec announcements. To verify the allow them to digitally sign BGPsec announcements. To verify the
signature, the public key, in the form of a certificate [I-D.ietf- signature, the public key, in the form of a certificate [I-D.ietf-
sidr-bgpsec-pki-profiles], is published in the Resource Public Key sidr-bgpsec-pki-profiles], is published in the Resource Public Key
Infrastructure (RPKI). This document describes provisioning of Infrastructure (RPKI). This document describes provisioning of
BGPsec-speaking routers with the appropriate public- private key- BGPsec-speaking routers with the appropriate public-private key-
pairs. There are two sub-methods, router-driven and operator-driven. pairs. There are two sub-methods, router-driven and operator-driven.
These two sub-methods differ in where the keys are generated: on the These two sub-methods differ in where the keys are generated: on the
router in the router-driven method, and elsewhere in the operator- router in the router-driven method, and elsewhere in the operator-
driven method. Routers are required to support at least one of the driven method. Routers are required to support at least one of the
methods in order to work in various deployment environments. Some methods in order to work in various deployment environments. Some
routers may not allow the private key to be off-loaded while others routers may not allow the private key to be off-loaded while others
may. While off-loading private keys would ease swapping of routing may. While off-loading private keys would ease swapping of routing
engines, exposure of private keys is a well known security risk. engines, exposure of private keys is a well known security risk.
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Hardware Security Module). This is by design and supports classic Hardware Security Module). This is by design and supports classic
PKI Certification Policies for (often human) subscribers which PKI Certification Policies for (often human) subscribers which
require the private key only ever be controlled by the subscriber to require the private key only ever be controlled by the subscriber to
ensure that no one can impersonate the subscriber. For non-humans, ensure that no one can impersonate the subscriber. For non-humans,
this model does not always work. For example, when an operator wants this model does not always work. For example, when an operator wants
to support hot-swappable routers the same private key needs to be to support hot-swappable routers the same private key needs to be
installed in the soon-to-be online router that was used by the the installed in the soon-to-be online router that was used by the the
soon-to-be offline router. This motivated the operator-driven model. soon-to-be offline router. This motivated the operator-driven model.
The remainder of this document describes how operators can use the The remainder of this document describes how operators can use the
two methods to provision new and existing routers. two methods to provision new and existing routers. The methods
described involve the operator configuring the two end points and
Useful References: [I-D.ietf-sidr-bgpsec-overview] gives an overview acting as the intermediary. Section 7 describes a method that
of the BGPsec protocol, [I-D.ietf-sidr-bgpsec-protocol] gives the requires more capable routers.
gritty details, [I-D.ietf-sidr-bgpsec-pki-profiles] specifies the
format for the PKCS #10 request, and [I-D.ietf-sidr-bgpsec-algs]
specifies the algorithms used to generate the signature.
Useful Formats: Formats for the objects used by routers are:
Private keys see [I-D.ietf-sidr-bgpsec-algs] concerning local storage
and Section 6 concerning PKCS#8 for operator-generated keys.
Public key certificates see [I-D.ietf-sidr-bgpsec-pki-profiles]
Certificate Status Request (CSR) see [I-D.ietf-sidr-bgpsec-pki- Useful References: [I-D.ietf-sidr-bgpsec-protocol] describes gritty
profiles] concerning the PKCS#10 requests and PKCS#7 responses. details, [I-D.ietf-sidr-bgpsec-pki-profiles] specifies the format for
the PKCS #10 request, and [I-D.ietf-sidr-bgpsec-algs] specifies the
algorithms used to generate the signature.
2. Management / Router Communication 2. Management / Router Communication
Operators are free to use either the router-driven or operator-driven Operators are free to use either the router-driven or operator-driven
method as supported by the platform. Regardless of the method method as supported by the platform. Regardless of the method
chosen, operators first establish a secure communication channel chosen, operators first establish a secure communication channel
between the management system and the router. How this channel is between the management system and the router. How this channel is
established is router-specific and is beyond scope of this document. established is router-specific and is beyond scope of this document.
Though other configuration mechanisms might be used, e.g. NetConf Though other configuration mechanisms might be used, e.g. NetConf
(see [RFC6470]); for simplicity, in this document, the communication (see [RFC6470]); for simplicity, in this document, the communication
channel between the management platform and the router is assumed to channel between the management platform and the router is assumed to
be an SSH-protected CLI. See Appendix A for security considerations be an SSH-protected CLI. See Appendix A for security considerations
for this channel. for this channel.
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channel between the management platform and the router is assumed to channel between the management platform and the router is assumed to
be an SSH-protected CLI. See Appendix A for security considerations be an SSH-protected CLI. See Appendix A for security considerations
for this channel. for this channel.
3. Exchanging Certificates 3. Exchanging Certificates
The operator management station can exchange certificate requests and The operator management station can exchange certificate requests and
certificates with routers and with the RPKI CA infrastructure using certificates with routers and with the RPKI CA infrastructure using
the application/pkcs10 media type [RFC5967] and application/ the application/pkcs10 media type [RFC5967] and application/
pkcs7-mime [RFC5751], respectively, and may use FTP or HTTP per pkcs7-mime [RFC5751], respectively, and may use FTP or HTTP per
[RFC2585], or the Enrollment over Secure Transport [RFC7030]. [RFC2585], or the Enrollment over Secure Transport (EST) [RFC7030].
4. Set-Up 4. Set-Up
To start, the operator uses the communication channel to install the To start, the operator uses the communication channel to install the
appropriate RPKI Trust Anchor' Certificate (TA Cert) in the router. appropriate RPKI Trust Anchor' Certificate (TA Cert) in the router.
This will later enable the router to validate the router certificate This will later enable the router to validate the router certificate
returned in the PKCS#7. returned in the PKCS#7.
The operator also configures the Autonomous System (AS) number to be The operator also configures the Autonomous System (AS) number to be
used in the generated router certificate. This may be the sole AS used in the generated router certificate. This may be the sole AS
configured on the router, or an operator choice if the router is configured on the router, or an operator choice if the router is
configured with multiple ASs. configured with multiple ASs.
The operator configures or extracts from the router the BGP RouterID The operator configures or extracts from the router the BGP RouterID
to be used in the generated certificate. In the case where the to be used in the generated certificate. In the case where the
operator has chosen not to use unique per-router certificates, a operator has chosen not to use unique per-router certificates, a
RouterID of 0 may be used. RouterID of 0 may be used.
5. PKCS#10 Generation 5. PKCS#10 Generation
The private key, and hence the PKCS#10 request may be generated by The private key, and hence the PKCS#10 request, which is sometimes
the router or by the operator. referred to as a Certificate Signing Request (CSR), may be generated
by the router or by the operator.
5.1. Router-Generated Keys 5.1. Router-Generated Keys
In the router-generated method, once the protected session is In the router-generated method, once the protected session is
established and the initial Set-Up (Section 4) performed, the established and the initial Set-Up (Section 4) performed, the
operator issues a command or commands for the router to generate the operator issues a command or commands for the router to generate the
public/private key pair, to generate the PKCS#10 request, and to sign public/private key pair, to generate the PKCS#10 request, and to sign
the PKCS#10 with the private key. Once generated, the PKCS#10 is the PKCS#10 with the private key. Once generated, the PKCS#10 is
returned to the operator over the protected channel. returned to the operator over the protected channel.
If a router was to communicate directly with a CA to have the CA If a router was to communicate directly with a CA to have the CA
certify the PKCS#10, there would be no way for the CA to authenticate certify the PKCS#10, there would be no way for the CA to authenticate
the router. As the operator knows the authenticity of the router, the router. As the operator knows the authenticity of the router,
the operator must mediate the communication with the CA. the operator mediates the communication with the CA.
The operator adds the chosen AS number and the RouterID to send to The operator adds the chosen AS number and the RouterID to send to
the RPKI CA for the CA to certify. the RPKI CA for the CA to certify.
5.2. Operator-Generated Keys 5.2. Operator-Generated Keys
In the operator-generated method, the operator generates the public/ In the operator-generated method, the operator generates the
private key pair on a management station and installs the private key public/private key pair on a management station and installs the
into the router over the protected channel. Beware that experience private key into the router over the protected channel. Beware that
has shown that copy and paste from a management station to a router experience has shown that copy and paste from a management station to
can be unreliable for long texts. a router can be unreliable for long texts.
Alternatively, the private key may be encapsulated in a PKCS #8 Alternatively, the private key may be encapsulated in a PKCS #8
[RFC5958], the PKCS#8 is further encapsulated in Cryptographic [RFC5958], the PKCS#8 is further encapsulated in Cryptographic
Message Syntax (CMS) SignedData [RFC5652], and signed by the AS's End Message Syntax (CMS) SignedData [RFC5652], and signed by the AS's End
Entity (EE) certificate. Entity (EE) certificate.
The router SHOULD verify the signature of the encapsulated PKCS#8 to The router SHOULD verify the signature of the encapsulated PKCS#8 to
ensure the returned private key did in fact come from the operator, ensure the returned private key did in fact come from the operator,
but this requires that the operator also provision via the CLI or but this requires that the operator also provision via the CLI or
include in the SignedData the RPKI CA certificate and relevant AS's include in the SignedData the RPKI CA certificate and relevant AS's
EE certificate(s). The router should inform the operator whether or EE certificate(s). The router should inform the operator whether or
not the signature validates to a trust anchor; this notification not the signature validates to a trust anchor; this notification
mechanism is out of scope. mechanism is out of scope.
The operator then creates and signs the PKCS#10 with the private key, The operator then creates and signs the PKCS#10 with the private key,
and adds the chosen AS number and RouterID to be sent to the RPKI CA and adds the chosen AS number and RouterID to be sent to the RPKI CA
for the CA to certify. for the CA to certify.
6. Installing Signed Keys 6. Installing Certified Keys
The operator uses RPKI management tools to communicate with the The operator uses RPKI management tools to communicate with the
global RPKI system to have the appropriate CA validate the PKCS#10 global RPKI system to have the appropriate CA validate the PKCS#10
request, sign the key in the PKCS#10 and generated PKCS#7 response, request, sign the key in the PKCS#10 (i.e., certify it) and generated
as well as publishing the certificate in the Global RPKI. External PKCS#7 response, as well as publishing the certificate in the Global
network connectivity may be needed if the certificate is to be RPKI. External network connectivity may be needed if the certificate
published in the Global RPKI. is to be published in the Global RPKI.
After the CA certifies the key, it does two things: After the CA certifies the key, it does two things:
1. Publishes the certificate in the Global RPKI. The CA must have 1. Publishes the certificate in the Global RPKI. The CA must have
connectivity to the relevant publication point, which in turn connectivity to the relevant publication point, which in turn
must have external network connectivity as it is part of the must have external network connectivity as it is part of the
Global RPKI. Global RPKI.
2. Returns the certificate to the operator's management station, 2. Returns the certificate to the operator's management station,
packaged in a PKCS#7, using the corresponding method by which it packaged in a PKCS#7, using the corresponding method by which it
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Note: The signature on the PKCS#8 and Certificate need not be made by Note: The signature on the PKCS#8 and Certificate need not be made by
the same entity. Signing the PKCS#8, permits more advanced the same entity. Signing the PKCS#8, permits more advanced
configurations where the entity that generates the keys is not the configurations where the entity that generates the keys is not the
direct CA. direct CA.
Even if the operator cannot extract the private key from the router, Even if the operator cannot extract the private key from the router,
this signature still provides a linkage between a private key and a this signature still provides a linkage between a private key and a
router. That is the server can verify the proof of possession (POP), router. That is the server can verify the proof of possession (POP),
as required by [RFC6484]. as required by [RFC6484].
7. Key Management 7. Advanced Deployment Scenarios
More PKI-capable routers can take advantage of this increased
functionality and lighten the operator's burden. Typically, these
routers include either pre-installed manufacturer-generated
certificates (e.g., IEEE 802.1 AR [802.1AR]) or pre-installed
manufacturer-generated Pre-Shared Keys (PSK) as well as PKI-
enrollment functionality and transport protocol, e.g., CMC's "Secure
Transport" [RFC7030] or the original CMC transport protocol's
[RFC5273]. When the operator first establishes a secure
communication channel between the management system and the router,
this pre-installed key material is used to authenticate the router.
The operator burden shifts here to include:
1. Securely communicating the router's authentication material to
the CA prior to operator initiating the server's CSR. CAs use
authentication material to determine whether the router is
eligible to receive a certificate. Authentication material at a
minimum includes the router's AS number and RouterID as well as
the router's key material, but can also include additional
information. Authentication material can can be communicated to
the CA (i.e., CSRs signed by this key material are issued
certificates with this AS and RouterID) or to the router (i.e.,
the operator uses the vendor-supplied management interface to
include the AS number and routerID in the router-generated CSR).
2. Enabling the router to communicate with the CA. While the
router-to-CA communications are operator-initiated, the
operator's management interface need not be involved in the
communications path. Enabling the router-to-CA connectivity MAY
require connections to external networks (i.e., through
firewalls, NATs, etc.).
Once configured, the operator can begin the process of enrolling the
router. Because the router is communicating directly with the CA,
there is no need for the operator to retrieve the PKCS#10 from the
router or return the PKCS#7 to the router as in Section 6. Note that
the checks performed by the router, namely extracting the certificate
from the PKCS#7, verifying the private key corresponds to the
returned public key, and that the returned certificate validated back
to an installed trust anchor, SHOULD be performed. Likewise, the
router SHOULD notify the operator if any of these fail, but this
notification mechanism is out of scope.
When a router is so configured the communication with the CA SHOULD
be automatically re-established by the router at future times to
renew or rekey the certificate automatically when necessary (See
Section 8). This further reduces the tasks required of the operator.
8. Key Management
An operator's responsibilities do not end after key generation, key An operator's responsibilities do not end after key generation, key
provisioning, certificate issuance, and certificate distribution. provisioning, certificate issuance, and certificate distribution.
They persist for as long as the operator wishes to operate the They persist for as long as the operator wishes to operate the
BGPsec-speaking router. BGPsec-speaking router.
7.1. Key Validity 8.1. Key Validity
It is critical that a BGPsec speaking router ensures that it is It is critical that a BGPsec speaking router ensures that it is
signing with a valid certificate at all times. To this end, the signing with a valid private key at all times. To this end, the
operator needs to ensure the router always has a non-expired operator needs to ensure the router always has a non-expired
certificate. I.e. the key used to sign BGPsec announcements always certificate. I.e. the key used to sign BGPsec announcements always
has an associated certificate whose expiry time is after the current has an associated certificate whose expiry time is after the current
time. time.
Ensuring this is not terribly difficult but requires that either: Ensuring this is not terribly difficult but requires that either:
1. The router has a mechanism to notify the operator that the 1. The router has a mechanism to notify the operator that the
certificate has an impending expiration, and/or certificate has an impending expiration, and/or
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Regardless of the technique used to track router certificate expiry Regardless of the technique used to track router certificate expiry
times, it is advisable to notify additional operators in the same times, it is advisable to notify additional operators in the same
organization as the expiry time approaches thereby ensuring that the organization as the expiry time approaches thereby ensuring that the
forgetfulness of one operator does not affect the entire forgetfulness of one operator does not affect the entire
organization. organization.
Depending on inter-operator relationship, it may be helpful to notify Depending on inter-operator relationship, it may be helpful to notify
a peer operator that one or more of their certificates are about to a peer operator that one or more of their certificates are about to
expire. expire.
7.2. Key Roll-Over 8.2. Key Roll-Over
Routers that support multiple private keys also greatly increase the Routers that support multiple private keys also greatly increase the
chance that routers can continuously speak BGPsec because the new chance that routers can continuously speak BGPsec because the new
private key and certificate can be obtained and distributed prior to private key and certificate can be obtained and distributed prior to
expiration of the operational key. Obviously, the router needs to expiration of the operational key. Obviously, the router needs to
know when to start using the new key. Once the new key is being know when to start using the new key. Once the new key is being
used, having the already distributed certificate ensures continuous used, having the already distributed certificate ensures continuous
operation. operation.
Whether the certificate is re-keyed (i.e., different key in the Whether the certificate is re-keyed (i.e., different key in the
certificate with a new expiry time) or renewed (i.e., the same key in certificate with a new expiry time) or renewed (i.e., the same key in
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Routers which support more than one private key, where one is Routers which support more than one private key, where one is
operational and other(s) are soon-to-be-operational, facilitate operational and other(s) are soon-to-be-operational, facilitate
revocation events because the operator can configure the router to revocation events because the operator can configure the router to
make a soon-to-be-operational key operational, request revocation of make a soon-to-be-operational key operational, request revocation of
the compromised key, and then make a next generation soon-to-be- the compromised key, and then make a next generation soon-to-be-
operational key, all hopefully without needing to take offline or operational key, all hopefully without needing to take offline or
reboot the router. For routers which support only one operational reboot the router. For routers which support only one operational
key, the operators should create or install the new private key, and key, the operators should create or install the new private key, and
then request revocation of the compromised private key. then request revocation of the compromised private key.
7.4. Router Replacement 8.4. Router Replacement
Currently routers often generate private keys for uses such as SSH, Currently routers often generate private keys for uses such as SSH,
and the private keys may not be seen or off-loaded from the router. and the private keys may not be seen or off-loaded from the router.
While this is good security, it creates difficulties when a routing While this is good security, it creates difficulties when a routing
engine or whole router must be replaced in the field and all software engine or whole router must be replaced in the field and all software
which accesses the router must be updated with the new keys. Also, which accesses the router must be updated with the new keys. Also,
any network based initial contact with a new routing engine requires any network based initial contact with a new routing engine requires
trust in the public key presented on first contact. trust in the public key presented on first contact.
To allow operators to quickly replace routers without requiring To allow operators to quickly replace routers without requiring
update and distribution of the corresponding public keys in the RPKI, update and distribution of the corresponding public keys in the RPKI,
routers SHOULD allow the private BGPsec key to be off-loaded via a routers SHOULD allow the private BGPsec key to inserted via a
protected session, e.g. SSH, NetConf (see [RFC6470]), SNMP, etc. protected session, e.g., SSH, NetConf (see [RFC6470]), SNMP. This
This lets the operator upload the old private key via the mechanism lets the operator escrow the old private key via the mechanism used
used for operator-generated keys, see Section 5.2. for operator-generated keys, see Section 5.2, such that it can be re-
inserted into a replacement router. The router MAY allow the private
key to be to be off-loaded via the protected session, but this SHOULD
be paired with functionality that sets the key into a permanent non-
exportable state to ensure that it is not off-loaded at a future time
by unauthorized operations.
8. Security Considerations 9. Security Considerations
The router's manual will describe whether the router supports one, The router's manual will describe whether the router supports one,
the other, or both of the key generation options discussed in the the other, or both of the key generation options discussed in the
earlier sections of this draft as well as other important security- earlier sections of this draft as well as other important security-
related information (e.g., how to SSH to the router). After related information (e.g., how to SSH to the router). After
familiarizing one's self with the capabilities of the router, familiarizing one's self with the capabilities of the router,
operators are encouraged to ensure that the router is patched with operators are encouraged to ensure that the router is patched with
the latest software updates available from the manufacturer. the latest software updates available from the manufacturer.
This document defines no protocols so in some sense introduces no new This document defines no protocols so in some sense introduces no new
skipping to change at page 10, line 38 skipping to change at page 11, line 35
[I-D.ylonen-sshkeybcp]; employees that no longer need access to [I-D.ylonen-sshkeybcp]; employees that no longer need access to
routers SHOULD be removed the router to ensure only those authorized routers SHOULD be removed the router to ensure only those authorized
have access to a router. have access to a router.
Though the CA's certificate is installed on the router and used to Though the CA's certificate is installed on the router and used to
verify that the returned certificate is in fact signed by the CA, the verify that the returned certificate is in fact signed by the CA, the
revocation status of the CA's certificate is rarely checked as the revocation status of the CA's certificate is rarely checked as the
router may not have global connectivity or CRL-aware software. The router may not have global connectivity or CRL-aware software. The
operator MUST ensure that installed CA certificate is valid. operator MUST ensure that installed CA certificate is valid.
9. IANA Considerations 10. IANA Considerations
This document has no IANA Considerations. This document has no IANA Considerations.
10. References 11. References
10.1. Normative References 11.1. Normative References
[I-D.ietf-sidr-bgpsec-algs] [I-D.ietf-sidr-bgpsec-algs]
Turner, S., "BGP Algorithms, Key Formats, & Signature Turner, S., "BGP Algorithms, Key Formats, & Signature
Formats", draft-ietf-sidr-bgpsec-algs (work in Formats", draft-ietf-sidr-bgpsec-algs (work in
progress), March 2013. progress), March 2013.
[I-D.ietf-sidr-bgpsec-pki-profiles] [I-D.ietf-sidr-bgpsec-pki-profiles]
Reynolds, M., Turner, S., and S. Kent, "A Profile for Reynolds, M., Turner, S., and S. Kent, "A Profile for
BGPSEC Router Certificates, Certificate Revocation Lists, BGPSEC Router Certificates, Certificate Revocation Lists,
and Certification Requests", draft-ietf-sidr-bgpsec-pki- and Certification Requests", draft-ietf-sidr-bgpsec-pki-
profiles (work in progress), October 2012. profiles (work in progress), October 2012.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, DOI
10.17487/RFC2119, March 1997, <http://www.rfc-
editor.org/info/rfc2119>.
[RFC4086] Eastlake, D., Schiller, J., and S. Crocker, "Randomness [RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker,
Requirements for Security", BCP 106, RFC 4086, June 2005. "Randomness Requirements for Security", BCP 106, RFC 4086,
DOI 10.17487/RFC4086, June 2005, <http://www.rfc-
editor.org/info/rfc4086>.
[RFC4253] Ylonen, T. and C. Lonvick, "The Secure Shell (SSH) [RFC4253] Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH)
Transport Layer Protocol", RFC 4253, January 2006. Transport Layer Protocol", RFC 4253, DOI 10.17487/RFC4253,
January 2006, <http://www.rfc-editor.org/info/rfc4253>.
[RFC5652] Housley, R., "Cryptographic Message Syntax (CMS)", [RFC5652] Housley, R., "Cryptographic Message Syntax (CMS)", STD 70,
RFC 5652, September 2009. RFC 5652, DOI 10.17487/RFC5652, September 2009,
<http://www.rfc-editor.org/info/rfc5652>.
[RFC5958] Turner, S., "Asymmetric Key Packages", RFC 5958, August [RFC5958] Turner, S., "Asymmetric Key Packages", RFC 5958, DOI
2010. 10.17487/RFC5958, August 2010, <http://www.rfc-
editor.org/info/rfc5958>.
10.2. Informative References [802.1AR] IEEE SA-Standards Board, "IEEE Standard for Local and
metropolitan area networks - Secure Device Identity",
December 2009,
<http://standards.ieee.org/findstds/standard/802.1AR-
2009.html>.
[I-D.ietf-sidr-bgpsec-overview] 11.1. Informative References
Lepinski, M. and S. Turner, "An Overview of BGPSEC",
draft-ietf-sidr-bgpsec-overview (work in progress), May
2012.
[I-D.ietf-sidr-bgpsec-protocol] [I-D.ietf-sidr-bgpsec-protocol]
Lepinski, M., "BGPSEC Protocol Specification", draft-ietf- Lepinski, M., "BGPSEC Protocol Specification", draft-ietf-
sidr-bgpsec-protocol (work in progress), February 2013. sidr-bgpsec-protocol (work in progress), February 2013.
[I-D.ylonen-sshkeybcp] [I-D.ylonen-sshkeybcp]
Ylonen, T. and G. Kent, "Managing SSH Keys for Automated Ylonen, T. and G. Kent, "Managing SSH Keys for Automated
Access - Current Recommended Practice", draft-ylonen- Access - Current Recommended Practice", draft-ylonen-
sshkeybcp (work in progress), April 2013. sshkeybcp (work in progress), April 2013.
[RFC2585] Housley, R. and P. Hoffman, "Internet X.509 Public Key [RFC2585] Housley, R. and P. Hoffman, "Internet X.509 Public Key
Infrastructure Operational Protocols: FTP and HTTP", Infrastructure Operational Protocols: FTP and HTTP",
RFC 2585, May 1999. RFC 2585, DOI 10.17487/RFC2585, May 1999, <http://www.rfc-
editor.org/info/rfc2585>.
[RFC3766] Orman, H. and P. Hoffman, "Determining Strengths For [RFC3766] Orman, H. and P. Hoffman, "Determining Strengths For
Public Keys Used For Exchanging Symmetric Keys", BCP 86, Public Keys Used For Exchanging Symmetric Keys", BCP 86,
RFC 3766, April 2004. RFC 3766, DOI 10.17487/RFC3766, April 2004,
<http://www.rfc-editor.org/info/rfc3766>.
[RFC5273] Schaad, J. and M. Myers, "Certificate Management over CMS
(CMC): Transport Protocols", RFC 5273, DOI
10.17487/RFC5273, June 2008, <http://www.rfc-
editor.org/info/rfc5273>.
[RFC5480] Turner, S., Brown, D., Yiu, K., Housley, R., and T. Polk, [RFC5480] Turner, S., Brown, D., Yiu, K., Housley, R., and T. Polk,
"Elliptic Curve Cryptography Subject Public Key "Elliptic Curve Cryptography Subject Public Key
Information", RFC 5480, March 2009. Information", RFC 5480, DOI 10.17487/RFC5480, March 2009,
<http://www.rfc-editor.org/info/rfc5480>.
[RFC5647] Igoe, K. and J. Solinas, "AES Galois Counter Mode for the [RFC5647] Igoe, K. and J. Solinas, "AES Galois Counter Mode for the
Secure Shell Transport Layer Protocol", RFC 5647, August Secure Shell Transport Layer Protocol", RFC 5647, DOI
2009. 10.17487/RFC5647, August 2009, <http://www.rfc-
editor.org/info/rfc5647>.
[RFC5656] Stebila, D. and J. Green, "Elliptic Curve Algorithm [RFC5656] Stebila, D. and J. Green, "Elliptic Curve Algorithm
Integration in the Secure Shell Transport Layer", Integration in the Secure Shell Transport Layer",
RFC 5656, December 2009. RFC 5656, DOI 10.17487/RFC5656, December 2009,
<http://www.rfc-editor.org/info/rfc5656>.
[RFC5751] Ramsdell, B. and S. Turner, "Secure/Multipurpose Internet [RFC5751] Ramsdell, B. and S. Turner, "Secure/Multipurpose Internet
Mail Extensions (S/MIME) Version 3.2 Message Mail Extensions (S/MIME) Version 3.2 Message
Specification", RFC 5751, January 2010. Specification", RFC 5751, DOI 10.17487/RFC5751, January
2010, <http://www.rfc-editor.org/info/rfc5751>.
[RFC5967] Turner, S., "The application/pkcs10 Media Type", RFC 5967, [RFC5967] Turner, S., "The application/pkcs10 Media Type", RFC 5967,
August 2010. DOI 10.17487/RFC5967, August 2010, <http://www.rfc-
editor.org/info/rfc5967>.
[RFC6187] Igoe, K. and D. Stebila, "X.509v3 Certificates for Secure [RFC6187] Igoe, K. and D. Stebila, "X.509v3 Certificates for Secure
Shell Authentication", RFC 6187, March 2011. Shell Authentication", RFC 6187, DOI 10.17487/RFC6187,
March 2011, <http://www.rfc-editor.org/info/rfc6187>.
[RFC6470] Bierman, A., "Network Configuration Protocol (NETCONF) [RFC6470] Bierman, A., "Network Configuration Protocol (NETCONF)
Base Notifications", RFC 6470, February 2012. Base Notifications", RFC 6470, DOI 10.17487/RFC6470,
February 2012, <http://www.rfc-editor.org/info/rfc6470>.
[RFC6484] Kent, S., Kong, D., Seo, K., and R. Watro, "Certificate [RFC6484] Kent, S., Kong, D., Seo, K., and R. Watro, "Certificate
Policy (CP) for the Resource Public Key Infrastructure Policy (CP) for the Resource Public Key Infrastructure
(RPKI)", BCP 173, RFC 6484, February 2012. (RPKI)", BCP 173, RFC 6484, DOI 10.17487/RFC6484, February
2012, <http://www.rfc-editor.org/info/rfc6484>.
[RFC6668] Bider, D. and M. Baushke, "SHA-2 Data Integrity [RFC6668] Bider, D. and M. Baushke, "SHA-2 Data Integrity
Verification for the Secure Shell (SSH) Transport Layer Verification for the Secure Shell (SSH) Transport Layer
Protocol", RFC 6668, July 2012. Protocol", RFC 6668, DOI 10.17487/RFC6668, July 2012,
<http://www.rfc-editor.org/info/rfc6668>.
[RFC7030] Pritikin, M., Ed., Yee, P., Ed., and D. Harkins, Ed., [RFC7030] Pritikin, M., Ed., Yee, P., Ed., and D. Harkins, Ed.,
"Enrollment over Secure Transport", RFC 7030, "Enrollment over Secure Transport", RFC 7030, DOI
DOI 10.17487/RFC7030, October 2013, 10.17487/RFC7030, October 2013, <http://www.rfc-
<http://www.rfc-editor.org/info/rfc7030>. editor.org/info/rfc7030>.
[SP800-57] National Institute of Standards and Technology (NIST),
Special Publication 800-57: Recommendation for Key
Management - Part 1 (Revised), March 2007.
Appendix A. Management/Router Channel Security Appendix A. Management/Router Channel Security
Encryption, integrity, authentication, and key exchange algorithms Encryption, integrity, authentication, and key exchange algorithms
used by the secure communication channel SHOULD be of equal or used by the secure communication channel SHOULD be of equal or
greater strength than the BGPsec keys they protect, which for the greater strength than the BGPsec keys they protect, which for the
algorithm specified in [I-D.ietf-sidr-bgpsec-algs] is 128-bit; see algorithm specified in [I-D.ietf-sidr-bgpsec-algs] is 128-bit; see
[RFC5480] and by reference [SP800-57] for information about this [RFC5480] and by reference [SP800-57] for information about this
strength claim as well as [RFC3766] for "how to determine the length strength claim as well as [RFC3766] for "how to determine the length
of an asymmetric key as a function of a symmetric key strength of an asymmetric key as a function of a symmetric key strength
skipping to change at page 13, line 13 skipping to change at page 14, line 40
for integrity, ecdsa-sha2-nistp256 [RFC5656] for authentication, and for integrity, ecdsa-sha2-nistp256 [RFC5656] for authentication, and
ecdh-sha2-nistp256 [RFC5656] for key exchange. ecdh-sha2-nistp256 [RFC5656] for key exchange.
Some routers support the use of public key certificates and SSH. The Some routers support the use of public key certificates and SSH. The
certificates used for the SSH session are different than the certificates used for the SSH session are different than the
certificates used for BGPsec. The certificates used with SSH should certificates used for BGPsec. The certificates used with SSH should
also enable a level of security commensurate with BGPsec keys; also enable a level of security commensurate with BGPsec keys;
x509v3-ecdsa-sha2-nistp256 [RFC6187] could be used for x509v3-ecdsa-sha2-nistp256 [RFC6187] could be used for
authentication. authentication.
Appendix B. The n00b Guide to BGPsec Key Management
This appendix is informative. It attempts to explain all of the PKI
technobabble in plainer language.
BGPsec speakers send signed BGPsec updates that are verified by other
BGPsec speakers. In PKI parlance, the senders are referred to as
signers and the receivers are referred to as relying parties. The
signers with which we are concerned here are routers signing BGPsec
updates. Signers use private keys to sign and relying parties use
the corresponding public keys, in the form of X.509 public key
certificates, to verify signatures. The third party involved is the
entity that issues the X.509 public key certificate, the
Certification Authority (CA). Key management is all about making
these key pairs and the certificates, as well as ensuring that the
relying parties trust that the certified public keys in fact
correspond to the signers' private keys.
The specifics of key management greatly depend on the routers as well
as management interfaces provided by the routers' vendor. Because of
these differences, it is hard to write a definitive "how to," but
this guide is intended to arm operators with enough information to
ask the right questions. The other aspect that makes this guide
informative is that the steps for the do-it-yourself (DIY) approach
involve arcane commands while the GUI-based vendor-assisted
management console approach will likely hide all of those commands
behind some button clicks. Regardless, the operator will end up with
a BGPsec-enabled router. Initially, we focus on the DIY approach and
then follow up with some information about the GUI-based approach.
The first step in the DIY approach is to generate a private key; but
in fact what you do is create a key pair; one part, the private key,
is kept very private and the other part, the public key, is given out
to verify whatever is signed. The two models for how to create the
key pair are the subject of this document, but it boils down to
either doing it on-router (router-driven) or off-router (operator-
driven).
If you are generating keys on the router (router-driven), then you
will need to access the router. Again, how you access the router is
router-specific, but generally the DIY approach uses the CLI and
accessing the router either directly via the router's craft port or
over the network on an administrative interface. If accessing the
router over the network be sure to do it securely (i.e., use SSHv2).
Once logged into the router, issue a command or a series of commands
that will generate the key pair for the algorithms noted in the main
body of this document; consult your router's documentation for the
specific commands. The key generation process will yield multiple
files: the private key and the public key; the file format varies
depending on the arcane command you issued, but generally the files
are DER or PEM-encoded.
The second step is to generate the certification request, which is
often referred to as a certificate signing request (CSR) or PKCS#10,
and to send it to the CA to be signed. To generate the CSR, you
issue some more arcane commands while logged into the router; using
the private key just generated to sign the certification request with
the algorithms specified in the main body of this document; the CSR
is signed to prove to the CA that the router has possession of the
private key (i.e., the signature is the proof-of-possession). The
output of the command is the CSR file; the file format varies
depending on the arcane command you issued, but generally the files
are DER or PEM-encoded.
The third step is to retrieve the signed CSR from the router and send
it to the CA. But before sending it, you need to also send the CA
the subject name and serial number for the router. The CA needs this
information to issue the certificate. How you get the CSR to the CA,
is beyond the scope of this document. While you are still connected
to the router, install the Trust Anchor (TA) for the root of the PKI.
At this point, you no longer need access to the router for BGPsec-
related initiation purposes.
The fourth step is for the CA to issue the certificate based on the
CSR you sent; the certificate will include the subject name, serial
number, public key, and other fields as well as being signed by the
CA. After the CA issues the certificate, the CA returns the
certificate, and posts the certificate to the RPKI repository. Check
that the certificate corresponds to the private key by verifying the
signature on the CSR sent to the CA; this is just a check to make
sure that the CA issued a certificate corresponding to the private
key on the router.
If generating the keys off-router (operator-driven), then the same
steps are used as the on-router key generation, (possibly with the
same arcane commands as those used in the on-router approach), but no
access to the router is needed the first three steps are done on an
administrative workstation: o Step 1: Generate key pair; o Step 2:
Create CSR and sign CSR with private key, and; o Step 3: Send CSR
file with the subject name and serial number to CA.
After the CA has returned the certificate and you have checked the
certificate, you need to put the private key and TA in the router.
Assuming the DIY approach, you will be using the CLI and accessing
the router either directly via the router's craft port or over the
network on an admin interface; if accessing the router over the
network make doubly sure it is done securely (i.e., use SSHv2)
because the private key is being moved over the network. At this
point, access to the router is no longer needed for BGPsec-related
initiation purposes.
NOTE: Regardless of the approach taken, the first three steps could
trivially be collapsed by a vendor-provided script to yield the
private key and the signed CSR.
Given a GUI-based vendor-assisted management console, then all of
these steps will likely be hidden behind pointing and clicking the
way through GPsec-enabling the router.
The scenarios described above require the operator to access each
router, which does not scale well to large networks. An alternative
would be to create an image, perform the necessary steps to get the
private key and trust anchor on the image, and then install the image
via a management protocol.
One final word of advice; certificates include a notAfter field that
unsurprisingly indicates when relying parties should no longer trust
the certificate. To avoid having routers with expired certificates
follow the recommendations in the Certification Policy (CP) [RFC6484]
and make sure to renew the certificate at least one week prior to the
notAfter date. Set a calendar reminder in order not to forget!
Authors' Addresses Authors' Addresses
Randy Bush Randy Bush
IIJ / Dragon Research Labs IIJ / Dragon Research Labs
5147 Crystal Springs 5147 Crystal Springs
Bainbridge Island, Washington 98110 Bainbridge Island, Washington 98110
US US
Email: randy@psg.com Email: randy@psg.com
Sean Turner Sean Turner
sn3rd sn3rd
Email: sean@sn3rd.com Email: sean@sn3rd.com
Keyur Patel Keyur Patel
Cisco Systems Arrcus, Inc.
170 W. Tasman Drive
San Jose, CA 95134
USA
Email: keyupate@cisco.com Email: keyur@arrcus.com
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