Secure Inter-Domain Routing D. Mandelberg
Internet-Draft BBN Technologies
Intended status: Best Current Practice October 7, 2015
Expires: April 9, 2016
Simplified Local internet nUmber Resource Management with the RPKI
draft-ietf-sidr-slurm-00
Abstract
The Resource Public Key Infrastructure (RPKI) is a global
authorization infrastructure that allows the holder of Internet
Number Resources (INRs) to make verifiable statements about those
resources. Network operators, e.g., Internet Service Providers
(ISPs), can use the RPKI to validate BGP route origination
assertions. In the future, ISPs also will be able to use the RPKI to
validate the path of a BGP route. Some ISPs locally use BGP with
private address space or private AS numbers (see RFC6890). These
local BGP routes cannot be verified by the global RPKI, and SHOULD be
considered invalid based on the global RPKI (see RFC6491). The
mechanisms described below provide ISPs with a way to make local
assertions about private (reserved) INRs while using the RPKI's
assertions about all other INRs.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on April 9, 2016.
Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
2. Validation Output Filtering . . . . . . . . . . . . . . . . . 4
3. Locally Adding Assertions . . . . . . . . . . . . . . . . . . 4
4. Configuring SLURM . . . . . . . . . . . . . . . . . . . . . . 4
5. Combining Mechanisms . . . . . . . . . . . . . . . . . . . . 7
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
7. Security Considerations . . . . . . . . . . . . . . . . . . . 8
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
9.1. Informative References . . . . . . . . . . . . . . . . . 8
9.2. Normative References . . . . . . . . . . . . . . . . . . 10
Appendix A. Example SLURM File . . . . . . . . . . . . . . . . . 10
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 11
1. Introduction
The Resource Public Key Infrastructure (RPKI) is a global
authorization infrastructure that allows the holder of Internet
Number Resources (INRs) to make verifiable statements about those
resources. For example, the holder of a block of IP(v4 or v6)
addresses can issue a Route Origination Authorization (ROA) [RFC6482]
to authorize an Autonomous System (AS) to originate routes for that
block.
Internet Service Providers (ISPs) can then use the RPKI to validate
BGP routes. (Validation of the origin of a route is described in
[RFC6483], and validation of the path of a route is described in
[I-D.ietf-sidr-bgpsec-overview].) However, some ISPs locally use BGP
with private address space ([RFC1918], [RFC4193], [RFC6598]) or
private AS numbers ([RFC1930], [RFC6996]). These local BGP routes
cannot be verified by the global RPKI, and SHOULD be considered
invalid when using the RPKI. For example, [RFC6491] recommends the
creation of ROAs that would invalidate routes for reserved and
unallocated address space.
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This document specifies two new mechanisms to enable ISPs to make
local assertions about some INRs while using the RPKI's assertions
about all other INRs. These mechanisms support the second and third
use cases in [I-D.ietf-sidr-lta-use-cases]. The second use case
describes use of [RFC1918] addresses or use of public address space
not allocated to the ISP that is using it. The third use case
describes a situation in which an ISP publishes a variant of the RPKI
hierarchy (for its customers). In this variant some prefixes and/or
AS numbers are different from what the RPKI repository system
presents to the general ISP population. The result is that routes
for consumers of this variant hierarchy will be re-directed (via
routing).
Both mechanisms are specified in terms of abstract sets of
assertions. For Origin Validation [RFC6483], an assertion is a tuple
of {IP prefix, prefix length, maximum length, AS number} as used by
rpki-rtr version 0 [RFC6810] and version 1
[I-D.ietf-sidr-rpki-rtr-rfc6810-bis]. For BGPsec
[I-D.ietf-sidr-bgpsec-overview], an assertion is a tuple of {AS
number, subject key identifier, router public key} as used by rpki-
rtr version 1. Output Filtering, described in Section 2, filters out
any assertions by the RPKI about locally reserved INRs. Locally
Adding Assertions, described in Section 3, adds local assertions
about locally reserved INRs. The combination of both mechanisms is
described in Section 5.
To ensure local consistency, the effect of SLURM MUST be atomic.
That is, the output of the relying party must be either the same as
if SLURM were not used, or it must reflect the entire SLURM
configuration. For an example of why this is required, consider the
case of two local routes for the same prefix but different origin AS
numbers. Both routes are configured with Locally Adding Assertions.
If neither addition occurs, then both routes could be in the unknown
state [RFC6483]. If both additions occur then both routes would be
in the valid state. However, if one addition occurs and the other
does not, then one could be invalid while the other is valid.
In general, the primary output of an RPKI relying party is the data
it sends to routers over the rpki-rtr protocol. The rpki-rtr
protocol enables routers to query a relying party for all assertions
it knows about (Reset Query) or for an update of only the changes in
assertions (Serial Query). The mechanisms specified in this document
are to be applied to the result set for a Reset Query, and to both
the old and new sets that are compared for a Serial Query. Relying
party software MAY modify other forms of output in comparable ways,
but that is outside the scope of this document.
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This document is intended to supersede [I-D.ietf-sidr-ltamgmt] while
focusing only on local management of private INRs. Another draft
[I-D.kent-sidr-suspenders] focuses on the other aspects of local
management.
1.1. Terminology
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 [RFC2119].
2. Validation Output Filtering
To prevent the global RPKI from affecting routes with locally
reserved INRs, a relying party may be locally configured with a list
of IP prefixes and/or AS numbers that are used locally, and taken
from reserved INR spaces. Any Origin Validation assertions where the
IP prefix is equal to or subsumed by a locally reserved IP prefix,
are removed from the relying party's output. Any Origin Validation
assertions where the IP prefix contains a locally reserved IP prefix
are removed; the relying party software SHOULD issue a warning when
this action is taken. (Note that an Origin Validation assertion is
not removed due to its AS number matching a locally reserved AS
number.) Any BGPsec assertion where the AS number is equal to a
locally reserved AS number is removed from the relying party's
output.
3. Locally Adding Assertions
Each relying party is locally configured with a (possibly empty) list
of assertions. This list is added to the relying party's output.
4. Configuring SLURM
Relying party software SHOULD support the following configuration
format for Validation Output Filtering and Locally Adding Assertions.
The format is defined using the Augmented Backus-Naur Form (ABNF)
notation and core rules from [RFC5234] and the rules <IPv4address>
and <IPv6address> from Appendix A of [RFC3986]. See Appendix A for
an example SLURM file.
A SLURM configuration file, <SLURMFile>, consists of a head and a
body. The head identifies the file as a SLURM configuration file,
specifies the version of SLURM for which the file was written, and
optionally contains other information described below. The body
contains the configuration for Validation Output Filtering and
Locally Adding Assertions.
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SLURMFile = head body
head = firstLine *(commentLine / headLine)
body = *(commentLine / bodyLine)
firstLine = %x53.4c.55.52.4d SP "1.0" EOL ; "SLURM 1.0"
commentLine = *WSP [comment] EOL
headLine = *WSP headCommand [ 1*WSP [comment] ] EOL
bodyLine = *WSP bodyCommand [ 1*WSP [comment] ] EOL
comment = "#" *(VCHAR / WSP)
EOL = CRLF / LF
The head may specify a target. If present, the target string
identifies the environment in which the SLURM file is intended to be
used. The meaning of the target string, if any, is determined by the
user. If a target is present, a relying party SHOULD verify that
that the target is an acceptable value, and reject the SLURM file if
the target is not acceptable. For example, the relying party could
be configured to accept SLURM files only if they do not specify a
target, have a target value of "hostname=rpki.example.com", or have a
target value of "as=65536". If more than one target line is present,
all targets must be acceptable to the RP.
headCommand = target
target =
%x74.61.72.67.65.74 1*WSP ; "target"
1*VCHAR
The body contains zero or more configuration lines for Validation
Output Filtering and Locally Adding Assertions. Each <del> command
specifies an INR to use for Validation Output Filtering. Each <add>
command specifies an assertion to use for Locally Adding Assertions.
bodyCommand = add / del
add =
%x61.64.64 1*WSP ; "add"
addItem
del =
%x64.65.6c 1*WSP ; "del"
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delItem
addItem = addItemPrefixAS / addItemASKey
; Add a mapping from a prefix and max length to an AS number.
addItemPrefixAS =
%x6f.72.69.67.69.6e.61.74.69.6f.6e 1*WSP ; "origination"
IPprefixMaxLen 1*WSP
ASnum
; Add a mapping from an AS number to a router public key.
addItemASKey =
%x62.67.70.73.65.63 1*WSP ; "bgpsec"
ASnum 1*WSP
RouterSKI 1*WSP
RouterPubKey
delItem = delItemPrefix / delItemAS
; Filter prefix-AS mappings, using the given prefix
delItemPrefix =
%x6f.72.69.67.69.6e.61.74.69.6f.6e 1*WSP ; "origination"
IPprefix
; Filter AS-key mappings for the given AS
delItemAS =
%x62.67.70.73.65.63 1*WSP ; "bgpsec"
ASnum
IPprefix = IPv4prefix / IPv6prefix
IPprefixMaxLen = IPv4prefixMaxLen / IPv6prefixMaxLen
IPv4prefix = IPv4address "/" 1*2DIGIT
IPv6prefix = IPv6address "/" 1*3DIGIT
; In the following two rules, if the maximum length component is
; missing, it is treated as equal to the prefix length.
IPv4prefixMaxLen = IPv4prefix ["-" 1*2DIGIT]
IPv6prefixMaxLen = IPv6prefix ["-" 1*3DIGIT]
ASnum = 1*DIGIT
; This is the Base64 [RFC4648] encoding of a router certificate's
; Subject Key Identifer, as described in
; [I-D.ietf-sidr-bgpsec-pki-profiles] and [RFC6487]. This is the
; value of the ASN.1 OCTET STRING without the ASN.1 tag or length
; fields.
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RouterSKI = Base64
; This is the Base64 [RFC4648] encoding of a router public key's
; subjectPublicKeyInfo value, as described in
; [I-D.ietf-sidr-bgpsec-algs]. This is the full ASN.1 DER encoding
; of the subjectPublicKeyInfo, including the ASN.1 tag and length
; values of the subjectPublicKeyInfo SEQUENCE.
RouterPubKey = Base64
Base64 = 1*(ALPHA / DIGIT / "+" / "/") 0*2"="
An implementation MAY support the concurrent use of multiple SLURM
files. In this case, the resulting inputs to Validation Output
Filtering and Locally Adding Assertions are the respective unions of
the inputs from each file. The typical use case for multiple files
is when the files have distinct scopes. For example, an organization
may belong to two separate networks that use different private-use IP
prefixes and AS numbers. To detect conflict between multiple SLURM
files, a relying party SHOULD issue a warning in the following cases:
1. There may be conflicting changes to Origin Validation assertions
if there exists an IP address X and distinct SLURM files Y,Z such
that X is contained by any prefix in any <addItemPrefixAS> or
<delItemPrefix> in file Y and X is contained by any prefix in any
<addItemPrefixAS> or <delItemPrefix> in file Z.
2. There may be conflicting changes to BGPsec assertions if there
exists an AS number X and distinct SLURM files Y,Z such that X is
used in any <addItemASKey> or <delItemAS> in file Y and X is used
in any <addItemASKey> or <delItemAS> in file Z.
5. Combining Mechanisms
In the typical use case, a relying party uses both output filtering
and locally added assertions. In this case, the resulting assertions
MUST be the same as if output filtering were performed before locally
adding assertions. I.e., locally added assertions MUST NOT be
removed by output filtering.
If a relying party chooses to use both SLURM and Suspenders
[I-D.kent-sidr-suspenders], the SLURM mechanisms MUST be performed on
the output of Suspenders.
6. IANA Considerations
TBD
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7. Security Considerations
The mechanisms described in this document provide a network operator
with additional ways to control its own network while making use of
RPKI data. These mechanisms are applied only locally; they do not
influence how other network operators interpret RPKI data.
Nonetheless, care should be taken in how these mechanisms are
employed.
8. Acknowledgements
The author would like to thank Stephen Kent for his guidance and
detailed reviews of this document. Thanks go to Wesley Wang for the
idea behind the target command, to Declan Ma for the idea behind use
of multiple SLURM files, and to Richard Hansen for his careful
reviews.
9. References
9.1. Informative References
[I-D.ietf-sidr-bgpsec-overview]
Lepinski, M., "An Overview of BGPsec", draft-ietf-sidr-
bgpsec-overview-07 (work in progress), June 2015.
[I-D.ietf-sidr-lta-use-cases]
Bush, R., "RPKI Local Trust Anchor Use Cases", draft-ietf-
sidr-lta-use-cases-03 (work in progress), June 2015.
[I-D.ietf-sidr-ltamgmt]
Reynolds, M., Kent, S., and M. Lepinski, "Local Trust
Anchor Management for the Resource Public Key
Infrastructure", draft-ietf-sidr-ltamgmt-08 (work in
progress), April 2013.
[I-D.ietf-sidr-rpki-rtr-rfc6810-bis]
Bush, R. and R. Austein, "The Resource Public Key
Infrastructure (RPKI) to Router Protocol", draft-ietf-
sidr-rpki-rtr-rfc6810-bis-06 (work in progress), October
2015.
[I-D.kent-sidr-suspenders]
Kent, S. and D. Mandelberg, "Suspenders: A Fail-safe
Mechanism for the RPKI", draft-kent-sidr-suspenders-03
(work in progress), April 2015.
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[RFC1918] Rekhter, Y., Moskowitz, B., Karrenberg, D., de Groot, G.,
and E. Lear, "Address Allocation for Private Internets",
BCP 5, RFC 1918, DOI 10.17487/RFC1918, February 1996,
<http://www.rfc-editor.org/info/rfc1918>.
[RFC1930] Hawkinson, J. and T. Bates, "Guidelines for creation,
selection, and registration of an Autonomous System (AS)",
BCP 6, RFC 1930, DOI 10.17487/RFC1930, March 1996,
<http://www.rfc-editor.org/info/rfc1930>.
[RFC4193] Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast
Addresses", RFC 4193, DOI 10.17487/RFC4193, October 2005,
<http://www.rfc-editor.org/info/rfc4193>.
[RFC6482] Lepinski, M., Kent, S., and D. Kong, "A Profile for Route
Origin Authorizations (ROAs)", RFC 6482,
DOI 10.17487/RFC6482, February 2012,
<http://www.rfc-editor.org/info/rfc6482>.
[RFC6483] Huston, G. and G. Michaelson, "Validation of Route
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>.
[RFC6491] Manderson, T., Vegoda, L., and S. Kent, "Resource Public
Key Infrastructure (RPKI) Objects Issued by IANA",
RFC 6491, DOI 10.17487/RFC6491, February 2012,
<http://www.rfc-editor.org/info/rfc6491>.
[RFC6598] Weil, J., Kuarsingh, V., Donley, C., Liljenstolpe, C., and
M. Azinger, "IANA-Reserved IPv4 Prefix for Shared Address
Space", BCP 153, RFC 6598, DOI 10.17487/RFC6598, April
2012, <http://www.rfc-editor.org/info/rfc6598>.
[RFC6810] Bush, R. and R. Austein, "The Resource Public Key
Infrastructure (RPKI) to Router Protocol", RFC 6810,
DOI 10.17487/RFC6810, January 2013,
<http://www.rfc-editor.org/info/rfc6810>.
[RFC6890] Cotton, M., Vegoda, L., Bonica, R., Ed., and B. Haberman,
"Special-Purpose IP Address Registries", BCP 153,
RFC 6890, DOI 10.17487/RFC6890, April 2013,
<http://www.rfc-editor.org/info/rfc6890>.
[RFC6996] Mitchell, J., "Autonomous System (AS) Reservation for
Private Use", BCP 6, RFC 6996, DOI 10.17487/RFC6996, July
2013, <http://www.rfc-editor.org/info/rfc6996>.
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9.2. Normative References
[I-D.ietf-sidr-bgpsec-algs]
Turner, S., "BGP Algorithms, Key Formats, & Signature
Formats", draft-ietf-sidr-bgpsec-algs-11 (work in
progress), August 2015.
[I-D.ietf-sidr-bgpsec-pki-profiles]
Reynolds, M. and S. Kent, "A Profile for BGPsec Router
Certificates, Certificate Revocation Lists, and
Certification Requests", draft-ietf-sidr-bgpsec-pki-
profiles-11 (work in progress), August 2015.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, DOI 10.17487/RFC3986, January 2005,
<http://www.rfc-editor.org/info/rfc3986>.
[RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data
Encodings", RFC 4648, DOI 10.17487/RFC4648, October 2006,
<http://www.rfc-editor.org/info/rfc4648>.
[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234,
DOI 10.17487/RFC5234, January 2008,
<http://www.rfc-editor.org/info/rfc5234>.
[RFC6487] Huston, G., Michaelson, G., and R. Loomans, "A Profile for
X.509 PKIX Resource Certificates", RFC 6487,
DOI 10.17487/RFC6487, February 2012,
<http://www.rfc-editor.org/info/rfc6487>.
Appendix A. Example SLURM File
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SLURM 1.0
# This file is only intended to be used on a relying party running
# on rpki.example.com.
target hostname=rpki.example.com # this is a comment
# Reserve IP prefixes for local use.
del origination 10.0.0.0/24
del origination fd0b:dd1d:2dcc::/48
# Reserve AS numbers for local use.
del bgpsec 64512
del bgpsec 64513
# Allow either 64512 or 64513 to originate routes to 10.0.0.0/24.
add origination 10.0.0.0/24 64512
add origination 10.0.0.0/24 64513
# 64512 originates fd0b:dd1d:2dcc::/52 and sub-prefixes up to length
# 56.
add origination fd0b:dd1d:2dcc::/52-56 64512
# However, 64513 originates fd0b:dd1d:2dcc:42::/64.
add origination fd0b:dd1d:2dcc:42::/64 64513
# 64513 also originates fd0b:dd1d:2dcc:100::/52
add origination fd0b:dd1d:2dcc:100::/52 64513
# Authorize router keys to sign BGPsec paths on behalf of the
# specified ASes. Note that the Base64 strings used in this
# example are not valid SKIs or router public keys, due to line
# length restrictions in RFCs.
add bgpsec 64512 Zm9v VGhpcyBpcyBub3QgYSByb3V0ZXIgcHVibGljIGtleQ==
add bgpsec 64512 YmFy b3IgYSBmbG9jayBvZiBkdWNrcw==
add bgpsec 64513 YWJj bWF5YmUgYSBkaWZmZXJlbnQgYXZpYW4gY2Fycmllcj8=
Author's Address
David Mandelberg
BBN Technologies
10 Moulton St.
Camridge, MA 02138
US
Email: david@mandelberg.org
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