Security Assessment of the IPv6 Flow Label
draft-gont-6man-flowlabel-security-03

IPv6 maintenance Working Group (6man)                            F. Gont
Internet-Draft                                                   UK CPNI
Intended status: BCP                                      March 12, 2012
Expires: September 13, 2012

               Security Assessment of the IPv6 Flow Label
                 draft-gont-6man-flowlabel-security-03

Abstract

   This document discusses the security implications of the IPv6 "Flow
   Label" header field, and analyzes possible schemes for selecting the
   Flow Label value of IPv6 packets.

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.  This document may not be modified,
   and derivative works of it may not be created, and it may not be
   published except as an Internet-Draft.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on September 13, 2012.

Copyright Notice

   Copyright (c) 2012 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Gont                   Expires September 13, 2012               [Page 1]
Internet-Draft             Flow Label Security                March 2012

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Vulnerability analysis . . . . . . . . . . . . . . . . . . . .  4
     2.1.  RFC3697-compliant implementations  . . . . . . . . . . . .  4
       2.1.1.  DoS resulting from verification of Flow Label
               consistency  . . . . . . . . . . . . . . . . . . . . .  4
       2.1.2.  Covert channels  . . . . . . . . . . . . . . . . . . .  5
       2.1.3.  QoS theft  . . . . . . . . . . . . . . . . . . . . . .  5
       2.1.4.  Information Leaking  . . . . . . . . . . . . . . . . .  5
     2.2.  RFC6437-compliant implementations  . . . . . . . . . . . .  6
   3.  Selecting Flow Label values  . . . . . . . . . . . . . . . . .  7
     3.1.  Recommended algorithm  . . . . . . . . . . . . . . . . . .  7
     3.2.  Alternative Algorithm  . . . . . . . . . . . . . . . . . .  7
       3.2.1.  Secret-key considerations  . . . . . . . . . . . . . . 10
   4.  Security Considerations  . . . . . . . . . . . . . . . . . . . 11
   5.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 12
   6.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 13
   7.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
     7.1.  Normative References . . . . . . . . . . . . . . . . . . . 14
     7.2.  Informative References . . . . . . . . . . . . . . . . . . 14
   Appendix A.  Survey of Flow Label selection algorithms in use
                by some popular implementations . . . . . . . . . . . 16
     A.1.  FreeBSD  . . . . . . . . . . . . . . . . . . . . . . . . . 16
     A.2.  Linux  . . . . . . . . . . . . . . . . . . . . . . . . . . 16
     A.3.  NetBSD . . . . . . . . . . . . . . . . . . . . . . . . . . 16
     A.4.  OpenBSD  . . . . . . . . . . . . . . . . . . . . . . . . . 16
     A.5.  OpenSolaris  . . . . . . . . . . . . . . . . . . . . . . . 16
   Appendix B.  Changes from previous versions of the draft (to
                be removed by the RFC Editor before publication
                of this document as a RFC . . . . . . . . . . . . . . 17
     B.1.  Changes from draft-gont-6man-flowlabel-security-02 . . . . 17
     B.2.  Changes from draft-gont-6man-flowlabel-security-01 . . . . 17
     B.3.  Changes from draft-gont-6man-flowlabel-security-00 . . . . 17
   Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 18

Gont                   Expires September 13, 2012               [Page 2]
Internet-Draft             Flow Label Security                March 2012