RE: Is the invariants draft really standards track?

"Lubashev, Igor" <ilubashe@akamai.com> Wed, 27 May 2020 16:07 UTC

Return-Path: <ilubashe@akamai.com>
X-Original-To: quic@ietfa.amsl.com
Delivered-To: quic@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 56C5A3A0EF0 for <quic@ietfa.amsl.com>; Wed, 27 May 2020 09:07:16 -0700 (PDT)
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, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, HTML_MESSAGE=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=unavailable autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=akamai.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 yT5sz5RFRYfA for <quic@ietfa.amsl.com>; Wed, 27 May 2020 09:07:14 -0700 (PDT)
Received: from mx0a-00190b01.pphosted.com (mx0a-00190b01.pphosted.com [IPv6:2620:100:9001:583::1]) (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 980C33A0EED for <quic@ietf.org>; Wed, 27 May 2020 09:07:14 -0700 (PDT)
Received: from pps.filterd (m0050093.ppops.net [127.0.0.1]) by m0050093.ppops.net-00190b01. (8.16.0.42/8.16.0.42) with SMTP id 04RG4gnP023723; Wed, 27 May 2020 17:07:03 +0100
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=akamai.com; h=from : to : cc : subject : date : message-id : references : in-reply-to : content-type : mime-version; s=jan2016.eng; bh=kvl3WnX+QHIdOkVG/JeB3tBx0cuMcEaSPs1bsrg7t2o=; b=mhODIO49L9gRJq8dUul3MxL/cyoAP7BpheHIeoXCgZoIiHu5YFuJF6PA6fQdS1iAneWN 4kYJByZwwlc5df1amLO7SVhLRXZ1f2LcwWr/m2Y3tMd9zCY3UXg8ZLnD3rv0xyPSMeyG C72ik6aT5oR42GaEGUPHptcwOHxb/2LPy5iNteU/b7QO2Nh4IUfv4hSC1V0wKJIAlCpI itmVsDk1YNxmpB7AoaQA3HtHP2kuZcCm+IHws6U+Ul9S6fQHtyR5NzvBSAaAUGNe8qZQ JSc2rf7HGQtvUytb0HPHmpVNzbg1ZQz881CAvAnUmRAGeYNMb/t+Omk1GwE2MboXRE98 KQ==
Received: from prod-mail-ppoint4 (a72-247-45-32.deploy.static.akamaitechnologies.com [72.247.45.32] (may be forged)) by m0050093.ppops.net-00190b01. with ESMTP id 316u3wtmh8-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 27 May 2020 17:07:02 +0100
Received: from pps.filterd (prod-mail-ppoint4.akamai.com [127.0.0.1]) by prod-mail-ppoint4.akamai.com (8.16.0.27/8.16.0.27) with SMTP id 04RG25vD019021; Wed, 27 May 2020 12:07:01 -0400
Received: from email.msg.corp.akamai.com ([172.27.123.53]) by prod-mail-ppoint4.akamai.com with ESMTP id 316y5vb6qj-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT); Wed, 27 May 2020 12:07:00 -0400
Received: from USMA1EX-DAG1MB5.msg.corp.akamai.com (172.27.123.105) by usma1ex-dag1mb3.msg.corp.akamai.com (172.27.123.103) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Wed, 27 May 2020 12:06:57 -0400
Received: from USMA1EX-DAG1MB5.msg.corp.akamai.com ([172.27.123.105]) by usma1ex-dag1mb5.msg.corp.akamai.com ([172.27.123.105]) with mapi id 15.00.1497.006; Wed, 27 May 2020 12:06:57 -0400
From: "Lubashev, Igor" <ilubashe@akamai.com>
To: Christian Huitema <huitema@huitema.net>, Kyle Rose <krose@krose.org>, "Ian Swett" <ianswett=40google.com@dmarc.ietf.org>
CC: Lars Eggert <lars@eggert.org>, IETF QUIC WG <quic@ietf.org>, Martin Duke <martin.h.duke@gmail.com>, Jared Mauch <jared@puck.nether.net>
Subject: RE: Is the invariants draft really standards track?
Thread-Topic: Is the invariants draft really standards track?
Thread-Index: AQHWM4bg7m/IhU9tKEaMc9qs7omEcqi7wjeAgACBhgCAAA8vAIAAAZ8A///Fg1A=
Date: Wed, 27 May 2020 16:06:57 +0000
Message-ID: <f4922cdb59014202900de44cc5fea0ff@usma1ex-dag1mb5.msg.corp.akamai.com>
References: <CAM4esxQBqfrz24riPQA_VGKcGp_TzW0pqb97KfFMtNdW9pUfDg@mail.gmail.com> <833A693C-62E6-4889-9954-FCE65A839A7C@eggert.org> <CAKcm_gPMO2DtqvKucqVw0zDjSniSOmFD4p1Tp4YLjr9WSWdEUw@mail.gmail.com> <CAJU8_nUN42gGmQof24XD9-EjXedyzcarDyRP8MGe1qW-BZ=+Aw@mail.gmail.com> <9cd91c24-c730-22a4-7aa0-baf61613b3ce@huitema.net>
In-Reply-To: <9cd91c24-c730-22a4-7aa0-baf61613b3ce@huitema.net>
Accept-Language: en-US
Content-Language: en-US
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
x-ms-exchange-transport-fromentityheader: Hosted
x-originating-ip: [172.19.45.26]
Content-Type: multipart/alternative; boundary="_000_f4922cdb59014202900de44cc5fea0ffusma1exdag1mb5msgcorpak_"
MIME-Version: 1.0
X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.216, 18.0.687 definitions=2020-05-27_03:2020-05-27, 2020-05-27 signatures=0
X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-2004280000 definitions=main-2005270123
X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.216, 18.0.687 definitions=2020-05-27_03:2020-05-27, 2020-05-27 signatures=0
X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 mlxlogscore=999 spamscore=0 adultscore=0 cotscore=-2147483648 mlxscore=0 bulkscore=0 priorityscore=1501 lowpriorityscore=0 phishscore=0 malwarescore=0 impostorscore=0 clxscore=1011 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2005270123
Archived-At: <https://mailarchive.ietf.org/arch/msg/quic/1HG1Ce4BfOStzEZwrCO1zANm5qU>
X-BeenThere: quic@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Main mailing list of the IETF QUIC working group <quic.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/quic>, <mailto:quic-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/quic/>
List-Post: <mailto:quic@ietf.org>
List-Help: <mailto:quic-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/quic>, <mailto:quic-request@ietf.org?subject=subscribe>
X-List-Received-Date: Wed, 27 May 2020 16:07:16 -0000

I’m working on a manageability draft PR for this (how to rate limit UDP to reduce disruption to QUIC if you have to rate limit UDP).  ETA end of the week (if I do not get pulled into something again).

The relevant observation is that DDoS with UDP that is indistinguishable from QUIC will happen.  UDP is already the most prevalent DDoS vector, since it is easy for a compromised non-admin app to send a flood of huge UDP packets (with TCP you get throttled by the congestion controller).  So there WILL be DDoS protection devices out there to try to mitigate the problem, possibly by observing both directions of the flow and deciding whether a packet belongs to a valid flow or not.

Since such middle boxes will be created, the more explicit and normative Invariants are about what one can expect, the less such middle boxes may decide for themselves.  For example (I did not think long about it), if some elements of path validation could land into Invariants (roughly, “no more than X packets/bytes can be sent on a new path w/o a return packet”), a DDoS middle box may use this fact and active connection migration might still have a chance during an attack (NAT rebinding could be linked by DDoS boxes to an old connection via unchanged CID).


  *   Igor


From: Christian Huitema <huitema@huitema.net>
Sent: Wednesday, May 27, 2020 11:34 AM

On 5/27/2020 8:28 AM, Kyle Rose wrote:
On Wed, May 27, 2020 at 10:34 AM Ian Swett <ianswett=40google.com@dmarc.ietf.org<mailto:40google.com@dmarc.ietf.org>> wrote:
I was agreeing with MT, but I'm happy to see some more MUSTs added if people feel that'd be helpful.

Coincidentally, we were just talking about this internally at Akamai yesterday. IMO, an invariants document isn't really helpful if it isn't normative, and for it to be normative it (or a related practices doc for operators) really needs to spell out clear boundaries for operators with MUSTs..

The example that came up yesterday was around operators filtering QUIC in the event of a DDoS: one recommendation based on some conversations going back at least to Prague 2019 was to hash packets on 4-tuple and filter those below a hash value chosen for a desired ingress limit instead of doing what most operators do with UDP today, which is to cap UDP throughput and just drop packets randomly or tail drop.

Interesting. Did they consider using the CID, or a fraction of it? This looks entirely like the scenario for which we developed stateless retry.

This recommendation certainly imposes some constraints on future protocol development that motivate new invariants: for instance, it would preclude sharding a connection across multiple source ports (not that there is necessarily a reason to do this; it's just an example). But more importantly, it goes beyond invariants: it's one among many practices compatible with the current set of invariants, some reasonable and some terrible.

This would break the "preferred address" redirection. Preferred address migration may or may not be spelled out in the invariants.

Operators are going to do things to QUIC traffic, so it would be good to offer them recommendations that are compatible with broad deployability.



Yes, we do need the invariants for that.

-- Christian Huitema