Version Capability for BGP
draft-abraitis-bgp-version-capability-05

Network Working Group                                        D. Abraitis
Internet-Draft                                                 Hostinger
Intended status: Informational                            March 24, 2020
Expires: September 25, 2020

                       Version Capability for BGP
                draft-abraitis-bgp-version-capability-05

Abstract

   In this document, we introduce a new BGP capability that allows the
   advertisement of a BGP speaker's version.

Status of This Memo

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   This Internet-Draft will expire on September 25, 2020.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Specification of Requirements . . . . . . . . . . . . . . . .   2
   3.  Version Capability  . . . . . . . . . . . . . . . . . . . . .   2
   4.  Operation . . . . . . . . . . . . . . . . . . . . . . . . . .   3
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   5
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   5
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   5
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   In modern data center designs, we tend to have conventional hosts
   participating in the routing process.  And the fleet of hosts has
   different versions of routing daemon.  This means that
   troubleshooting is a crucial part to quickly identify the root cause.
   This document introduces the new BGP capability to advertise the
   version of the routing daemon.

2.  Specification of Requirements

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

3.  Version Capability

   The Version Capability is a new BGP capability [RFC5492].  The
   implementation is specific to the vendor.  The version is
   unstructured and can be defined in any format the vendor decides.

   The length of the version SHOULD be limited to 64 bytes.  This is the
   limit to allow other capabilities as much space as they require.  The
   version MUST NOT be empty.

   This capability is OPTIONAL.  The vendor MUST implement a capability
   switch to enable or disable it.

   In case you reached 255 bytes of capabilities, you can disable this
   capability.  The capability is designed more to non-production
   environments where you need more visibility for troubleshooting
   purposes.  It's RECOMMENDED to turn it only inside a single
   Autonomous System domain or Autonomous System Confederations.

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   Such protocols like LLDP, CDP can provide the same information as
   well, but in containerized environments, it's very hard and NOT
   RECOMMENDED run background processes.  To minimize operational costs
   it would help having all the necessary information in place.

                   +--------------------------------+
                   |    Version Length (1 octet)    |
                   +--------------------------------+
                   |      Version (variable)        |
                   +--------------------------------+

                                 Figure 1

   Version Length:

      The number of characters in the Version

   Version:

      The Version encoded via UTF-8

4.  Operation

   The Version capability MUST only be used for displaying the version
   of a speaker to make troubleshooting easier.  You have a bunch of
   routers with a number of upstreams each.  All of them are with a
   different operating system and routing daemon installed.  Assuming
   that a specific feature is not working or a bug which is not fixed in
   an appropriate version, would allow us to quickly identify the
   pattern which versions are affected.

   Enabling this capability REQUIRED bouncing all existing BGP sessions.
   It MUST be explicitly configured to advertise the Version capability.

   Below is an example of implementation in [FRRouting] how it looks
   like with version advertised by a BGP sender:

:~# vtysh -c 'show ip bgp summary failed'
...
Neighbor      EstdCnt DropCnt ResetTime Reason
198.51.100.2        3       3  00:00:35 Waiting for peer OPEN (n/a)
198.51.100.3        3       3  00:01:12 Peer closed the session (FRRouting 7.2-b3ac21114g)
198.51.100.4        3       3  00:00:14 Peer closed the session (FRRouting 7.3-g4c566878f)
198.51.100.5        3       3  00:00:45 Peer closed the session (FRRouting 7.4-a25sg503g2)
...

                                 Figure 2

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   :~# vtysh -c 'show ip bgp neighbors 198.51.100.1 json' \
   > | jq '."198.51.100.1".neighborCapabilities.versions'
   {
     "advertisedVersion": "FRRouting 7.2-dev-MyOwnFRRVersion",
     "receivedVersion": "FRRouting 7.2-dev-MyOwnFRRVersion-gc68bb14"
   }

                                 Figure 3

5.  IANA Considerations

   IANA maintains the "Border Gateway Protocol (BGP) Parameters"
   registry with a subregistry called "Capabilities Codes".  IANA is
   requested to assign a capability number from the First Come First
   Served range for the Version Capability in this document as follows:

   +-------+-----------------+-----------------------------------------+
   | Value |   Description   |                Reference                |
   +-------+-----------------+-----------------------------------------+
   |  TBD  |     Version     | [draft-abraitis-bgp-version-capability] |
   |       |    Capability   |                                         |
   +-------+-----------------+-----------------------------------------+

                        Table 1: Version Capability

6.  Security Considerations

   The Version Capability can be treated as sensitive information, thus
   it would be easier for an attacker to exploit by knowing the specific
   version of the BGP speaker.  This information can be gathered in BGP
   OPEN messages.

   The Version Capability MUST be configurable with a vendor-specific
   knob to be able to enable or disable the capability.  The vendor
   might implement to disable this capability per neighbor.

   It would be safe to enable this for iBGP or inside the same tenant
   where you have full control and the BGP speaker is behind exit
   points.

   The Version Capability information can be gathered in BGP OPEN
   messages.

   Modifying the information advertised by a router might lead to
   attacks including bogus software upgrades and also might mask the
   causes of faults in the network.

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   Advertising which versions of code and from which vendor it comes may
   facilitate a number of social-engineering attacks.  A lot of BGP
   implementations leave TCP/179 open and this could lead to sensitive
   information disclosure.  This capability is NOT RECOMMENDED for eBGP
   use.

   Sensitive information leaks can be minimized by using the [RFC5082]
   mechanism or firewalls to filter out TCP 179 port from untrusted
   networks.  This capability can be disabled per neighbor, thus the
   sensitive information can't be disclosed to untrusted neighbors.

7.  References

7.1.  Normative References

   [FRRouting]
              Abraitis, D., "FRRouting - BGP Version Capability", 2019,
              <https://github.com/ton31337/frr/
              commit/4c566878fd1a7df9f8c84ee03f419c0b00ae444b>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

7.2.  Informative References

   [RFC3552]  Rescorla, E. and B. Korver, "Guidelines for Writing RFC
              Text on Security Considerations", BCP 72, RFC 3552,
              DOI 10.17487/RFC3552, July 2003,
              <https://www.rfc-editor.org/info/rfc3552>.

Author's Address

   Donatas Abraitis
   Hostinger
   Jonavos g. 60C
   Kaunas  44192
   LT

   Phone: +370 614 18958
   Email: donatas.abraitis@hostinger.com

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