Re: [TLS] Session resumption ticket reuse considered harmful

Nico Williams <nico@cryptonector.com> Fri, 06 March 2020 00:37 UTC

Return-Path: <nico@cryptonector.com>
X-Original-To: tls@ietfa.amsl.com
Delivered-To: tls@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id AD0723A0F7A for <tls@ietfa.amsl.com>; Thu, 5 Mar 2020 16:37:31 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.099
X-Spam-Level:
X-Spam-Status: No, score=-2.099 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (1024-bit key) header.d=cryptonector.com
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id EyS4zf4J8MUj for <tls@ietfa.amsl.com>; Thu, 5 Mar 2020 16:37:30 -0800 (PST)
Received: from caracal.birch.relay.mailchannels.net (caracal.birch.relay.mailchannels.net [23.83.209.30]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 7B0903A0F79 for <tls@ietf.org>; Thu, 5 Mar 2020 16:37:30 -0800 (PST)
X-Sender-Id: dreamhost|x-authsender|nico@cryptonector.com
Received: from relay.mailchannels.net (localhost [127.0.0.1]) by relay.mailchannels.net (Postfix) with ESMTP id 911934009F7; Fri, 6 Mar 2020 00:37:29 +0000 (UTC)
Received: from pdx1-sub0-mail-a85.g.dreamhost.com (100-96-1-27.trex.outbound.svc.cluster.local [100.96.1.27]) (Authenticated sender: dreamhost) by relay.mailchannels.net (Postfix) with ESMTPA id EF6684009AC; Fri, 6 Mar 2020 00:37:28 +0000 (UTC)
X-Sender-Id: dreamhost|x-authsender|nico@cryptonector.com
Received: from pdx1-sub0-mail-a85.g.dreamhost.com ([TEMPUNAVAIL]. [64.90.62.162]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384) by 0.0.0.0:2500 (trex/5.18.5); Fri, 06 Mar 2020 00:37:29 +0000
X-MC-Relay: Neutral
X-MailChannels-SenderId: dreamhost|x-authsender|nico@cryptonector.com
X-MailChannels-Auth-Id: dreamhost
X-Duck-Oafish: 1096f8b950f220a6_1583455049395_2070517840
X-MC-Loop-Signature: 1583455049395:2425772130
X-MC-Ingress-Time: 1583455049395
Received: from pdx1-sub0-mail-a85.g.dreamhost.com (localhost [127.0.0.1]) by pdx1-sub0-mail-a85.g.dreamhost.com (Postfix) with ESMTP id AE70380B29; Thu, 5 Mar 2020 16:37:23 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=cryptonector.com; h=date :from:to:cc:subject:message-id:references:mime-version :content-type:in-reply-to; s=cryptonector.com; bh=xG7NnEHZ+qlQGe dJMaOMsTgeRHk=; b=dU8rBpzDNNTewyMRSLvNRWUcPJUzjoNlaKsyBAH8dXz5RN Y/Y90jIM3oWRJdxN44/t0XYhMd08mlUeqJ+h0r4jsdpd3ykbl3TB7+mNvF2t51UZ o88AkP0fWTSFsvmPnc1SbeaGylBNztxPoJJgmcFZG3ANvTcp0XTFxKzASEHSE=
Received: from localhost (unknown [24.28.108.183]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: nico@cryptonector.com) by pdx1-sub0-mail-a85.g.dreamhost.com (Postfix) with ESMTPSA id B9C8C80B23; Thu, 5 Mar 2020 16:37:22 -0800 (PST)
Date: Thu, 05 Mar 2020 18:37:20 -0600
X-DH-BACKEND: pdx1-sub0-mail-a85
From: Nico Williams <nico@cryptonector.com>
To: Watson Ladd <watson@cloudflare.com>
Cc: IETF TLS <tls@ietf.org>
Message-ID: <20200306003719.GW18021@localhost>
References: <20200305205524.GR18021@localhost> <CAN2QdAGja9JoXsSSnmdkjHk7kNbDpEiMVkPpA6VDCfRjo9DRVw@mail.gmail.com> <20200305230821.GU18021@localhost> <CAN2QdAH6Z=+xt3+JWuJsZtE9sjmAxE1QHt9NqjeYynjmeznJrg@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Disposition: inline
In-Reply-To: <CAN2QdAH6Z=+xt3+JWuJsZtE9sjmAxE1QHt9NqjeYynjmeznJrg@mail.gmail.com>
User-Agent: Mutt/1.9.4 (2018-02-28)
X-VR-OUT-STATUS: OK
X-VR-OUT-SCORE: -100
X-VR-OUT-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrgedugedrudduuddgvdegucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecuggftfghnshhusghstghrihgsvgdpffftgfetoffjqffuvfenuceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmnecujfgurhepfffhvffukfhfgggtuggjfgesthdtredttdervdenucfhrhhomheppfhitghoucghihhllhhirghmshcuoehnihgtohestghrhihpthhonhgvtghtohhrrdgtohhmqeenucfkphepvdegrddvkedruddtkedrudekfeenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepmhhouggvpehsmhhtphdphhgvlhhopehlohgtrghlhhhoshhtpdhinhgvthepvdegrddvkedruddtkedrudekfedprhgvthhurhhnqdhprghthheppfhitghoucghihhllhhirghmshcuoehnihgtohestghrhihpthhonhgvtghtohhrrdgtohhmqedpmhgrihhlfhhrohhmpehnihgtohestghrhihpthhonhgvtghtohhrrdgtohhmpdhnrhgtphhtthhopehnihgtohestghrhihpthhonhgvtghtohhrrdgtohhm
Archived-At: <https://mailarchive.ietf.org/arch/msg/tls/_Jn38lxcqSldPonkeMGQgekXSNY>
Subject: Re: [TLS] Session resumption ticket reuse considered harmful
X-BeenThere: tls@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: "This is the mailing list for the Transport Layer Security working group of the IETF." <tls.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/tls>, <mailto:tls-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/tls/>
List-Post: <mailto:tls@ietf.org>
List-Help: <mailto:tls-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/tls>, <mailto:tls-request@ietf.org?subject=subscribe>
X-List-Received-Date: Fri, 06 Mar 2020 00:37:32 -0000

On Thu, Mar 05, 2020 at 04:21:56PM -0800, Watson Ladd wrote:
> On Thu, Mar 5, 2020 at 3:08 PM Nico Williams <nico@cryptonector.com> wrote:
> > > My skepticism is entirely a function of this being a late breaking
> > > [...]
> >
> > What is late breaking to you?
> >
> > The change was proposed during WGLC.  If before or during WGLC is too
> > late, when is it not too late?  At WG work item adoption call?
> 
> It depends on the relative size of the change and the importance of
> the issue. An important central issue that went completely unnoticed:

Thanks.  I agree about the relative size of the change, how substantial
it might be, and how necessary it might be.

> > > [...]
> >
> > Right, but this is where the "Postfix architecture" issue comes in.  I'm
> > having a conversation with him about this.  Viktor might be confused
> > about the CoW properties of LMDB, but in any case, the wire bandwidth
> > waste and server compute waste issues have nothing to do with Postfix's
> > architecture/design/implementation.
> 
> Tickets are small and issuance is cheap. Where are the *hard numbers*
> to back up the assertions being made that ticket reuse is an important
> savings?

How small they are appears to be in question.  See Viktor's post.

Nico
--