Handling of Overlapping IPv6 Fragments
draft-ietf-6man-overlap-fragment-03
Revision differences
Document history
Date | Rev. | By | Action |
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2012-08-22
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03 | (System) | post-migration administrative database adjustment to the No Objection position for Cullen Jennings |
2012-08-22
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03 | (System) | post-migration administrative database adjustment to the No Objection position for Pasi Eronen |
2012-08-22
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03 | (System) | post-migration administrative database adjustment to the No Objection position for Dan Romascanu |
2012-08-22
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03 | (System) | post-migration administrative database adjustment to the No Objection position for Adrian Farrel |
2012-08-22
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03 | (System) | post-migration administrative database adjustment to the No Objection position for Lars Eggert |
2009-11-30
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03 | Cindy Morgan | State Changes to RFC Ed Queue from Approved-announcement sent by Cindy Morgan |
2009-11-30
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03 | (System) | IANA Action state changed to No IC from In Progress |
2009-11-30
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03 | (System) | IANA Action state changed to In Progress |
2009-11-30
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03 | Amy Vezza | IESG state changed to Approved-announcement sent |
2009-11-30
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03 | Amy Vezza | IESG has approved the document |
2009-11-30
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03 | Amy Vezza | Closed "Approve" ballot |
2009-11-30
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03 | Jari Arkko | State Changes to Approved-announcement to be sent from IESG Evaluation::External Party by Jari Arkko |
2009-11-22
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03 | Adrian Farrel | [Ballot Position Update] Position for Adrian Farrel has been changed to No Objection from Discuss by Adrian Farrel |
2009-11-20
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03 | Samuel Weiler | Request for Last Call review by SECDIR Completed. Reviewer: Carl Wallace. |
2009-11-20
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03 | Dan Romascanu | [Ballot Position Update] Position for Dan Romascanu has been changed to No Objection from Discuss by Dan Romascanu |
2009-11-20
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03 | Jari Arkko | State Changes to IESG Evaluation::External Party from IESG Evaluation::AD Followup by Jari Arkko |
2009-11-20
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03 | Jari Arkko | Waiting for the WG, Dan, and Adrian to agree to my suggested changes. |
2009-11-20
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03 | (System) | Removed from agenda for telechat - 2009-11-19 |
2009-11-19
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03 | Cindy Morgan | State Changes to IESG Evaluation::AD Followup from IESG Evaluation by Cindy Morgan |
2009-11-19
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03 | Lars Eggert | [Ballot Position Update] Position for Lars Eggert has been changed to No Objection from Discuss by Lars Eggert |
2009-11-19
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03 | Cullen Jennings | [Ballot Position Update] Position for Cullen Jennings has been changed to No Objection from Discuss by Cullen Jennings |
2009-11-19
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03 | Pasi Eronen | [Ballot Position Update] Position for Pasi Eronen has been changed to No Objection from Discuss by Pasi Eronen |
2009-11-18
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03 | Ross Callon | [Ballot Position Update] New position, No Objection, has been recorded by Ross Callon |
2009-11-18
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03 | Amy Vezza | State Changes to IESG Evaluation from Waiting for AD Go-Ahead by Amy Vezza |
2009-11-18
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03 | Lisa Dusseault | [Ballot Position Update] New position, No Objection, has been recorded by Lisa Dusseault |
2009-11-18
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03 | Tim Polk | [Ballot Position Update] New position, No Objection, has been recorded by Tim Polk |
2009-11-18
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03 | Ron Bonica | [Ballot Position Update] New position, Yes, has been recorded by Ron Bonica |
2009-11-18
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03 | Cullen Jennings | [Ballot discuss] I agree with the basic recommendation of this draft that overlapping fragments should not be allowed (in v4 and v6) but I'm not … [Ballot discuss] I agree with the basic recommendation of this draft that overlapping fragments should not be allowed (in v4 and v6) but I'm not at all convinced by much of the rest of text. Was this reviewed by firewall people - my understanding tis the best practice in statefull inspection firewalls is to reconstruct the full packet. If this is true, the advice in the draft probably needs to be adjusted slightly. I find this draft very confusing. Why would a firewall allow a packet in because the SYN= ACK=1. Are you aware of any firewalls that would actually do this when there had not be an outbound SYN first? Are there really commonly used firewalls that use 1858 ? The statefull inspection firewalls I have used reassembled the packet. In section 4, what happens if you get a duplicate of a fragment? Is that an overlap causing discard? |
2009-11-18
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03 | Cullen Jennings | [Ballot Position Update] New position, Discuss, has been recorded by Cullen Jennings |
2009-11-18
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03 | Magnus Westerlund | [Ballot Position Update] New position, No Objection, has been recorded by Magnus Westerlund |
2009-11-17
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03 | Ralph Droms | [Ballot Position Update] New position, No Objection, has been recorded by Ralph Droms |
2009-11-17
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03 | Dan Romascanu | [Ballot discuss] The recommendation in section 4 includes: > When reassembling an IPv6 datagram, if one or more its constituent fragments is determined to … [Ballot discuss] The recommendation in section 4 includes: > When reassembling an IPv6 datagram, if one or more its constituent fragments is determined to be an overlapping fragment, the entire datagram (and any constituent fragments, including those not yet received), MUST be silently discarded. It is not clear what 'silently' means here. It looks like the discards due to such overlapping datagrams should be counted and reflected through some management interface, which may chose to send notifications about the attack for every or whenever a number of such events is recorded. In this case the discard is not completely 'silent'. |
2009-11-17
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03 | Dan Romascanu | [Ballot Position Update] New position, Discuss, has been recorded by Dan Romascanu |
2009-11-17
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03 | Adrian Farrel | [Ballot discuss] I think this is a fine piece of work, but I have some difficulty with the way it is positioned. It seems to … [Ballot discuss] I think this is a fine piece of work, but I have some difficulty with the way it is positioned. It seems to be a little too timid about updating the base IPv6 spec. According to the Abstract, this document has two purposes: - document the issues - update 2460 to ban overlaps. The Introduction, however, only talks about documenting the issues. As far as I can see, the update to 2460 is actually more important than the justification of the issues, so it would be good if the Introduction was a little more fullsome. But Section 4 is unclear. It is titled "Recommendation". If this work truly updates 2460, this is not a recommendation; it is a protocol modification. |
2009-11-17
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03 | Adrian Farrel | [Ballot Position Update] New position, Discuss, has been recorded by Adrian Farrel |
2009-11-16
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03 | Russ Housley | [Ballot comment] The Gen-ART Review by Francis Dupont on 29-Oct-2009 included a few editorial suggestions: - page 1: allows -> does not disallow?? … [Ballot comment] The Gen-ART Review by Francis Dupont on 29-Oct-2009 included a few editorial suggestions: - page 1: allows -> does not disallow?? - page 2: Acknowledgements -> Acknowledgments - page 3: the term 'check' is not enough because it is for protection, something like 'security check' should be better (but a bit too strong). - page 5: it is possible to get bad overlapping fragments from an error too (i.e., it is not always an attack, of course the action should be to drop the whole packet anyway). - page 6: received), MUST -> received) MUST? - page 6: Acknowledgements -> Acknowledgments |
2009-11-16
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03 | Russ Housley | [Ballot Position Update] New position, No Objection, has been recorded by Russ Housley |
2009-11-15
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03 | Alexey Melnikov | [Ballot Position Update] New position, No Objection, has been recorded by Alexey Melnikov |
2009-11-03
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03 | Lars Eggert | [Ballot comment] INTRODUCTION, paragraph 2: > Handling of overlapping IPv6 fragments Imprecise title. This ID isn't … [Ballot comment] INTRODUCTION, paragraph 2: > Handling of overlapping IPv6 fragments Imprecise title. This ID isn't about handling such fragments, it's about forbidding them. Section 4.5, paragraph 0: > This document explores the issues > that can be caused by overlapping fragments. Last sentence should add the "and updates 2460..." bit from the abstract. Section 3., paragraph 11: > The TCP header has the following values of the flags S(YN)=1 and > A(CK)=1. This may make an inspecting stateful firewall think that it > is a response packet for a connection request initiated from the > trusted side of the firewall. Hence it will allow the fragment to > pass. Stateful firewalls are called stateful because they track the transport protocol connection state. So a stateful firewall would *only* pass this packet *if* it was actually in response to a prior SYN in the opposiute direction. So I don't quite see how this attack is feasible. Section 4., paragraph 1: > IPv6 nodes transmitting datagrams that need to be fragmented MUST NOT > create overlapping fragments. When reassembling an IPv6 datagram, if > one or more its constituent fragments is determined to be an > overlapping fragment, the entire datagram (and any constituent > fragments, including those not yet received), MUST be silently > discarded. I agree that it must be discarded, but whether this is done silently is clearly a management decision of the local stack. Section 5., paragraph 1: > This document discusses an attack that can be used to bypass IPv6 > firewalls using overlapping fragments. It recommends disallowing > overlapping fragments in order to prevent this attack. Imprecise language: It doesn't just "recommend" it, it makes it a requirement. |
2009-11-03
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03 | Lars Eggert | [Ballot discuss] Section 8., paragraph 1: > [RFC1858] Ziemba, G., Reed, D., and P. Traina, "Security > … [Ballot discuss] Section 8., paragraph 1: > [RFC1858] Ziemba, G., Reed, D., and P. Traina, "Security > Considerations for IP Fragment Filtering", RFC 1858, > October 1995. DISCUSS: ** Downref: Normative reference to an Informational RFC: RFC 1858 Section 8., paragraph 4: > [RFC4942] Davies, E., Krishnan, S., and P. Savola, "IPv6 Transition/ > Co-existence Security Considerations", RFC 4942, > September 2007. DISCUSS: ** Downref: Normative reference to an Informational RFC: RFC 4942 |
2009-11-03
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03 | Lars Eggert | [Ballot Position Update] New position, Discuss, has been recorded by Lars Eggert |
2009-11-02
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03 | (System) | State has been changed to Waiting for AD Go-Ahead from In Last Call by system |
2009-11-02
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03 | Pasi Eronen | [Ballot discuss] I have reviewed draft-ietf-6man-overlap-fragment-03, and have one question that I'd like to discuss before recommending approval of the document: I'm wondering why … [Ballot discuss] I have reviewed draft-ietf-6man-overlap-fragment-03, and have one question that I'd like to discuss before recommending approval of the document: I'm wondering why the document does not recommend against (or completely prohibit) excessively small first fragments (or in other words, excessively small fragment offsets), similar to RFC 1858. For example, splitting the TCP header to in the middle (with src/dst port in one fragment, and the SYN/ACK/etc. flags in the other -- i.e. Fragment Offset=1) seems to be still allowed by this draft. But for obvious reasons, it's quite likely to confuse firewalls. (Of course, in IPv6 this situation cannot be completely ruled out, since in theory at least, destination options can be larger than the MTU. But that's unlikely to work in practice...) (Perhaps this is something the WG discussed already; in that case, I'd be interested in learning the rationale.) |
2009-11-02
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03 | Pasi Eronen | [Ballot Position Update] New position, Discuss, has been recorded by Pasi Eronen |
2009-10-22
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03 | Samuel Weiler | Request for Last Call review by SECDIR is assigned to Carl Wallace |
2009-10-22
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03 | Samuel Weiler | Request for Last Call review by SECDIR is assigned to Carl Wallace |
2009-10-21
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03 | Amanda Baber | IANA comments: As described in the IANA Considerations section, we understand this document to have NO IANA Actions. |
2009-10-19
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03 | Amy Vezza | Last call sent |
2009-10-19
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03 | Amy Vezza | State Changes to In Last Call from Last Call Requested by Amy Vezza |
2009-10-16
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03 | Jari Arkko | Placed on agenda for telechat - 2009-11-19 by Jari Arkko |
2009-10-16
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03 | Jari Arkko | Found no issues. Passing the document onwards. |
2009-10-16
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03 | Jari Arkko | Last Call was requested by Jari Arkko |
2009-10-16
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03 | Jari Arkko | State Changes to Last Call Requested from AD Evaluation by Jari Arkko |
2009-10-16
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03 | Jari Arkko | [Ballot Position Update] New position, Yes, has been recorded for Jari Arkko |
2009-10-16
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03 | Jari Arkko | Ballot has been issued by Jari Arkko |
2009-10-16
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03 | Jari Arkko | Created "Approve" ballot |
2009-10-16
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03 | (System) | Ballot writeup text was added |
2009-10-16
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03 | (System) | Last call text was added |
2009-10-16
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03 | (System) | Ballot approval text was added |
2009-10-16
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03 | Jari Arkko | State Changes to AD Evaluation from Publication Requested by Jari Arkko |
2009-10-16
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03 | Cindy Morgan | State Changes to Publication Requested from AD is watching by Cindy Morgan |
2009-10-16
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03 | Cindy Morgan | [Note]: 'Brian Haberman (brian@innovationslab.net) is the document shepherd.' added by Cindy Morgan |
2009-10-16
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03 | Cindy Morgan | (1.a) Who is the Document Shepherd for this document? Has the Document Shepherd personally reviewed this version of the … (1.a) Who is the Document Shepherd for this document? Has the Document Shepherd personally reviewed this version of the document and, in particular, does he or she believe this version is ready for forwarding to the IESG for publication? Brian Haberman (1.b) Has the document had adequate review both from key WG members and from key non-WG members? Does the Document Shepherd have any concerns about the depth or breadth of the reviews that have been performed? This document has received adequete review and the shepherd does not have any concerns with those reviews. (1.c) Does the Document Shepherd have concerns that the document needs more review from a particular or broader perspective, e.g., security, operational complexity, someone familiar with AAA, internationalization or XML? No. (1.d) Does the Document Shepherd have any specific concerns or issues with this document that the Responsible Area Director and/or the IESG should be aware of? For example, perhaps he or she is uncomfortable with certain parts of the document, or has concerns whether there really is a need for it. In any event, if the WG has discussed those issues and has indicated that it still wishes to advance the document, detail those concerns here. Has an IPR disclosure related to this document been filed? If so, please include a reference to the disclosure and summarize the WG discussion and conclusion on this issue. No concerns. (1.e) How solid is the WG consensus behind this document? Does it represent the strong concurrence of a few individuals, with others being silent, or does the WG as a whole understand and agree with it? The WG as a whole understands and supports this document. (1.f) Has anyone threatened an appeal or otherwise indicated extreme discontent? If so, please summarise the areas of conflict in separate email messages to the Responsible Area Director. (It should be in a separate email because this questionnaire is entered into the ID Tracker.) No. (1.g) Has the Document Shepherd personally verified that the document satisfies all ID nits? (See the Internet-Drafts Checklist and http://tools.ietf.org/tools/idnits/). Boilerplate checks are not enough; this check needs to be thorough. Has the document met all formal review criteria it needs to, such as the MIB Doctor, media type and URI type reviews? This version has 2 errors and 2 warnings from the id-nits check. These can be addressed when revisions are done for either IESG or IETF Last Call comments. (1.h) Has the document split its references into normative and informative? Are there normative references to documents that are not ready for advancement or are otherwise in an unclear state? If such normative references exist, what is the strategy for their completion? Are there normative references that are downward references, as described in [RFC3967]? If so, list these downward references to support the Area Director in the Last Call procedure for them [RFC3967]. There are two downward references listed in the Normative references section. (1.i) Has the Document Shepherd verified that the document IANA consideration section exists and is consistent with the body of the document? If the document specifies protocol extensions, are reservations requested in appropriate IANA registries? Are the IANA registries clearly identified? If the document creates a new registry, does it define the proposed initial contents of the registry and an allocation procedure for future registrations? Does it suggest a reasonable name for the new registry? See [RFC5226]. If the document describes an Expert Review process has Shepherd conferred with the Responsible Area Director so that the IESG can appoint the needed Expert during the IESG Evaluation? There are no IANA actions for this document. (1.j) Has the Document Shepherd verified that sections of the document that are written in a formal language, such as XML code, BNF rules, MIB definitions, etc., validate correctly in an automated checker? N/A. (1.k) The IESG approval announcement includes a Document Announcement Write-Up. Please provide such a Document Announcement Write-Up? Recent examples can be found in the "Action" announcements for approved documents. The approval announcement contains the following sections: Technical Summary The fragmentation and reassembly algorithm specified in the base IPv6 specification allows fragments to overlap. This document demonstrates the security issues with allowing overlapping fragments and updates the IPv6 specification to explicitly forbid overlapping fragments. Working Group Summary The 6MAN working group has done extensive review of this document and it represents the strong consensus of the group. Document Quality This document has been reviewed by key members of the 6MAN working group and the chairs. |
2009-10-16
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03 | Cindy Morgan | Intended Status has been changed to Proposed Standard from None |
2009-07-03
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03 | (System) | New version available: draft-ietf-6man-overlap-fragment-03.txt |
2009-03-09
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02 | (System) | New version available: draft-ietf-6man-overlap-fragment-02.txt |
2008-11-04
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01 | (System) | New version available: draft-ietf-6man-overlap-fragment-01.txt |
2008-10-27
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03 | Jari Arkko | Draft Added by Jari Arkko in state AD is watching |
2008-09-24
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00 | (System) | New version available: draft-ietf-6man-overlap-fragment-00.txt |