Re: [websec] #57: Re-add an upper limit to max-age

Joseph Bonneau <jbonneau@gmail.com> Fri, 22 March 2013 23:36 UTC

Return-Path: <jbonneau@gmail.com>
X-Original-To: websec@ietfa.amsl.com
Delivered-To: websec@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id D98C421F8C11 for <websec@ietfa.amsl.com>; Fri, 22 Mar 2013 16:36:44 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -3.599
X-Spam-Level:
X-Spam-Status: No, score=-3.599 tagged_above=-999 required=5 tests=[BAYES_00=-2.599, RCVD_IN_DNSWL_LOW=-1]
Received: from mail.ietf.org ([12.22.58.30]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id pwnaM7uWf6dL for <websec@ietfa.amsl.com>; Fri, 22 Mar 2013 16:36:44 -0700 (PDT)
Received: from mail-qe0-f46.google.com (mail-qe0-f46.google.com [209.85.128.46]) by ietfa.amsl.com (Postfix) with ESMTP id D3B2D21F8936 for <websec@ietf.org>; Fri, 22 Mar 2013 16:36:39 -0700 (PDT)
Received: by mail-qe0-f46.google.com with SMTP id a11so2676148qen.33 for <websec@ietf.org>; Fri, 22 Mar 2013 16:36:39 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=x-received:mime-version:in-reply-to:references:from:date:message-id :subject:to:cc:content-type; bh=LCHOXWdj59hcQvgv5/m+i9kIcIlyol6wAKwSWBvjJxk=; b=clsfHGUJRrn5j4NSq3XUK6doxf0u++90KLqB3yzmoYiKeMHn7YQ/jQ1IH8H6C+Dj0n 2i97/PwKRO/TzcMiS/YlVAu6lVgoqXp024W9PGldipxzTIVgJM87JNd6uzIRxEnMOKrY wh9fsJekMla1Dpec/uaKE8F/NyIwRbO/CFa3pQVdOd4fPo+oJz5uBAZ8fmSadm8sh2Z2 lQRb9aNDh2mtyBhCRvEE22aDefWJtIGolBbI3apzsizeR0w7Gv165/Gs7XuYgBLZRKiE WwJRP1yu88f8VolwcENTRpmPu2TjQSrbrA2aRna4VHV8JniL01rUO9VR2rTWqFQqAxPu 8ZGQ==
X-Received: by 10.49.64.72 with SMTP id m8mr1436424qes.51.1363995399360; Fri, 22 Mar 2013 16:36:39 -0700 (PDT)
MIME-Version: 1.0
Received: by 10.49.6.202 with HTTP; Fri, 22 Mar 2013 16:36:19 -0700 (PDT)
In-Reply-To: <CAGZ8ZG1HsW_SgB4OFRDPZT_3rUwsB8yvYxtE+fSpwLfoyrtHyg@mail.gmail.com>
References: <058.4066f40ba1a0e0b17085c25af1721605@trac.tools.ietf.org> <073.92e203ac2ffbca6a9b6ecd285f8d0e00@trac.tools.ietf.org> <CAGZ8ZG1HsW_SgB4OFRDPZT_3rUwsB8yvYxtE+fSpwLfoyrtHyg@mail.gmail.com>
From: Joseph Bonneau <jbonneau@gmail.com>
Date: Fri, 22 Mar 2013 19:36:19 -0400
Message-ID: <CAOe4Ui=1ADLZsHrHpFofQW48DpERfAENH0a5zUFta81PejCNUA@mail.gmail.com>
To: Trevor Perrin <trevp@trevp.net>
Content-Type: text/plain; charset="UTF-8"
Cc: websec issue tracker <trac+websec@trac.tools.ietf.org>, websec@ietf.org, sleevi@google.com
Subject: Re: [websec] #57: Re-add an upper limit to max-age
X-BeenThere: websec@ietf.org
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: Web Application Security Minus Authentication and Transport <websec.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/websec>, <mailto:websec-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/websec>
List-Post: <mailto:websec@ietf.org>
List-Help: <mailto:websec-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/websec>, <mailto:websec-request@ietf.org?subject=subscribe>
X-List-Received-Date: Fri, 22 Mar 2013 23:36:45 -0000

On Fri, Mar 22, 2013 at 7:07 PM, Trevor Perrin <trevp@trevp.net> wrote:
> With a spec maximum (say 30 days), then you have a clear reference
> point to plan around.

Agreed.

I have some stats I've been looking at from Google's web crawls about
HSTS headers. Out of 12853 hosts I observed setting HSTS, 53% set of a
max-age of 1 year. After that it's 15% 30 days, 12% 180 days, 10% 1
day, and a smattering of other choices (with a few large hosts like
Twitter setting very long-lived max-age).

These are only a rough upper bound on the max-age values that would be
set for pins, but it seems a substantial number of hosts would request
longer than 30 days, while 1 year will support most likely use cases,
so we should probably land somewhere between those two points.

The follow-on question is, if UAs allow max-age of 1 year, will there
need to be a revocation method to deal with some of the cases that
Trevor highlighted?