A Transport Layer Security (TLS) ClientHello Padding Extension
draft-ietf-tls-padding-04

[Ballot comment]
Like Ben:
-- 5, last sentence:
Do you expect anyone to implement this MAY? It seems like this either
needs to be stronger, or removed as a "why bother"?

In my spec, I usually write this way:
  Servers SHOULD verify that the extension
  is either empty or contains only zero bytes and log the exceptions.

[Ballot comment]
-- Abstract:
More in the abstract would be nice. Why'd would one want to do this?

-- 1, first paragraph, last sentence:
Can you elaborate on this? The motivation seems weak without a bit more. When would you choose to use this at all? Wouldn't it make more sense to fix the bug?

-- 5, last sentence:
Do you expect anyone to implement this MAY? It seems like this either needs to be stronger, or removed as a "why bother"?

-- 6:
I'm not sure I understand the meaning of  "permanently assign the early code point for the padding extension in its ExtensionType registry".
Does this mean that an early allocation was done for this? If so, it seems like the IANA section should still describe the code point being registered, or perhaps give a pointer to or description of the early allocation.

[Ballot comment]
As Alissa, I was wondering why it wasn’t easier to fix the one implementation instead. 

The shepherd wrote: "Since then it has been found that this extension can server (sic) to alleviate issues with issues in several vendor's products.  There was good consensus to move forward with this document as it may find further applicability in the future.”  So it looks like the problem is not just one implementation…

If the WG now thinks that this extension may be valuable for other things besides fixing bugs, then it might be nice to reword some of the document to not focus on what seems to be one bug and just present the extension for what it is: padding.

[Ballot comment]
Would be nice to include a reference to something that explains or at least identifies the implementation that hangs when receiving ClientHellos of a certain size. Otherwise one wonders why it's easier to define this extension than it is to just fix that one implementation (assuming it is only one).

(Via drafts-lastcall@iana.org): IESG/Authors/WG Chairs:

IANA has reviewed draft-ietf-tls-padding-01. Authors, please see below and let us know if our understanding of the document's IANA actions is inaccurate.

IANA's reviewer has the following comments:

Upon approval of this document, IANA will make the following change in the ExtensionType Values registry at http://www.iana.org/assignments/tls-extensiontype-values:

OLD:

21 padding (TEMPORARY - registered 2014-03-12, expires 2016-03-12) [draft-ietf-tls-padding]

NEW:

21 padding  [RFC-to-be]

The following Last Call announcement was sent out:

From: The IESG
To: IETF-Announce
CC:
Reply-To: ietf@ietf.org
Sender:
Subject: Last Call:  (A TLS ClientHello padding extension) to Proposed Standard


The IESG has received a request from the Transport Layer Security WG
(tls) to consider the following document:
- 'A TLS ClientHello padding extension'
  as Proposed Standard

The IESG plans to make a decision in the next few weeks, and solicits
final comments on this action. Please send substantive comments to the
ietf@ietf.org mailing lists by 2015-08-24. Exceptionally, comments may be
sent to iesg@ietf.org instead. In either case, please retain the
beginning of the Subject line to allow automated sorting.

Abstract


  This memo describes a TLS extension that can be used to pad
  ClientHello messages to a desired size.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-tls-padding/

IESG discussion can be tracked via
https://datatracker.ietf.org/doc/draft-ietf-tls-padding/ballot/


No IPR declarations have been submitted directly on this I-D.

As required by RFC 4858, this is the current template for the Document
Shepherd Write-Up.

Changes are expected over time. This version is dated 24 February 2012.

(1) What type of RFC is being requested (BCP, Proposed Standard,
Internet Standard, Informational, Experimental, or Historic)?  Why
is this the proper type of RFC?  Is this type of RFC indicated in the
title page header?

The requested type of RFC is standards track.  We had some discussion of the status in the working group and this was the rough consensus.

(2) 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

  This memo describes a TLS extension that can be used to pad
  ClientHello messages to a desired size.

Working Group Summary

This extension was originally introduced to work around a particular vendor's issue.  Its deployment was successful.  Since then it has been found that this extension can server to alleviate issues with issues in several vendor's products.  There was good consensus to move forward with this document as it may find further applicability in the future. 

Document Quality

  There are multiple interoperable implementations (web browsers and web servers) of this extension deployed today.  It works well to solve the problem.

Personnel

  Document Shepherd is Joseph Salowey
  The Responsible Area Director is Stephen Farrell

(3) Briefly describe the review of this document that was performed by
the Document Shepherd.  If this version of the document is not ready
for publication, please explain why the document is being forwarded to
the IESG.

The document Shepherd has reviewed the document and believes it is ready for publication. 

(4) Does the document Shepherd have any concerns about the depth or
breadth of the reviews that have been performed?

No

(5) Do portions of the document need review from a particular or from
broader perspective, e.g., security, operational complexity, AAA, DNS,
DHCP, XML, or internationalization? If so, describe the review that
took place.

The document has been reviewed in the TLS working group.  No need more specialized review has been identified.

(6) Describe any specific concerns or issues that the Document Shepherd
has 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.

No specific concerns

(7) Has each author confirmed that any and all appropriate IPR
disclosures required for full conformance with the provisions of BCP 78
and BCP 79 have already been filed. If not, explain why.

Yes

(8) Has an IPR disclosure been filed that references this document?
If so, summarize any WG discussion and conclusion regarding the IPR
disclosures.

No

(9) 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? 

(10) 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 publicly available.)

No

(11) Identify any ID nits the Document Shepherd has found in this
document. (See https://www.ietf.org/tools/idnits/ and the Internet-Drafts
Checklist). Boilerplate checks are not enough; this check needs to be
thorough.

None

(12) Describe how the document meets any required formal review
criteria, such as the MIB Doctor, media type, and URI type reviews.

No Formal review required

(13) Have all references within this document been identified as
either normative or informative?

Yes

(14) 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 plan for their completion?

No

(15) Are there downward normative references references (see RFC 3967)?
If so, list these downward references to support the Area Director in
the Last Call procedure.

No

(16) Will publication of this document change the status of any
existing RFCs? Are those RFCs listed on the title page header, listed
in the abstract, and discussed in the introduction? If the RFCs are not
listed in the Abstract and Introduction, explain why, and point to the
part of the document where the relationship of this document to the
other RFCs is discussed. If this information is not in the document,
explain why the WG considers it unnecessary.

This document does not affect other documents

(17) Describe the Document Shepherd's review of the IANA considerations
section, especially with regard to its consistency with the body of the
document. Confirm that all protocol extensions that the document makes
are associated with the appropriate reservations in IANA registries.
Confirm that any referenced IANA registries have been clearly
identified. Confirm that newly created IANA registries include a
detailed specification of the initial contents for the registry, that
allocations procedures for future registrations are defined, and a
reasonable name for the new registry has been suggested (see RFC 5226).

This document has already had an early code point assignment which is referenced in the document IANA section.  This document requests the early assignment be made permanent.

(18) List any new IANA registries that require Expert Review for future
allocations. Provide any public guidance that the IESG would find
useful in selecting the IANA Experts for these new registries.

No New registries

(19) Describe reviews and automated checks performed by the Document
Shepherd to validate sections of the document written in a formal
language, such as XML code, BNF rules, MIB definitions, etc.

Not applicable.