Subject: [TLS] Result of Working Group Last Call for draft-ietf-tls-padding-01

From: Joseph Salowey <[email-masked]>
Date: Sun, 22 Mar 2015 10:29:59 -0700

Below is my proto writeup for the draft-ietf-tls-padding-01.  Since there
were no comments on the draft during the last call I am going to request
the intended status as informational as the draft is documenting specific
practice that was used to work around a few specific implementations
problems that are being phased out.   If you would rather see the draft as
historic or standards track please respond to this message by March 27,
2015.

Thanks,

Joe

1. Summary

Joseph Salowey is the document shepherd and Stephen Farrell is the
responsible area director.

This document describes a TLS extension that can be used to pad ClientHello
messages to a desired size. This was done to work around implementation
problems from several TLS server implementations.

The requested status is informational since this is documenting a work
around to a particular implementation problem.

2. Review and Consensus

During the development and deployment of ALPN it was found that some TLS
server implementations had a problem with TLS ClientHellos of certain
sizes.  This extension allowed client implementations to work around this
problem until the server implementations are upgraded.   There was a lot of
review of this mechanism at that time and it was deployed to work around
the problem. A temporary extension number was assigned so implementations
could interoperate.

At this time there is less interest in the document because the problem is
solved by the extension and the reduction of faulty implementations,
however it is still useful to document this extension to preserve the
registration and in the case it ever becomes useful again.

3. Intellectual Property

No IPR declarations have been made on this document.

4. Other Points

There already is a temporary reservation in the IANA registry and this
document makes it permanent.

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From: Martin Thomson <[email-masked]>
Date: Sun, 22 Mar 2015 10:54:26 -0700

On 22 March 2015 at 10:29, Joseph Salowey <[email-masked]> wrote:
> were no comments on the draft during the last call I am going to request the
> intended status as informational as the draft is documenting specific

I see no reason not to move for PS, but could live with Info.

---

From: Yoav Nir <[email-masked]>
Date: Sun, 22 Mar 2015 13:21:20 -0500

> On Mar 22, 2015, at 12:54 PM, Martin Thomson <[email-masked]> wrote:
> 

The question is whether this is behavior that we want to standardize or a workaround that we want to document. 

Five years from now, and giving you the power to force everyone to upgrade their software, do you want this being used?

Yoav

---

From: Martin Thomson <[email-masked]>
Date: Sun, 22 Mar 2015 12:34:42 -0700

> Five years from now, and giving you the power to force everyone to upgrade their software, do you want this being used?

There is this feature in QUIC where their equivalent of the
ClientHello is padded to a certain significant size.  The theory there
is that you don't want your server to be used in a packet
amplification attack (ClientHello being generally smaller than the
ensuing flight from the server).  I think that perhaps there might be
a standards-based use for a feature that at least made the size of the
flights commensurate in size.