Re: [OAUTH-WG] OAuth 2.1 - require PKCE?

Steinar Noem <steinar@udelt.no> Wed, 06 May 2020 19:18 UTC

Return-Path: <steinar@udelt.no>
X-Original-To: oauth@ietfa.amsl.com
Delivered-To: oauth@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id E6B3A3A0AA8 for <oauth@ietfa.amsl.com>; Wed, 6 May 2020 12:18:45 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.895
X-Spam-Level:
X-Spam-Status: No, score=-1.895 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, HTML_FONT_LOW_CONTRAST=0.001, HTML_MESSAGE=0.001, SPF_HELO_NONE=0.001, SPF_NONE=0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=udelt-no.20150623.gappssmtp.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 lE0KjQHeEsWP for <oauth@ietfa.amsl.com>; Wed, 6 May 2020 12:18:40 -0700 (PDT)
Received: from mail-ot1-x330.google.com (mail-ot1-x330.google.com [IPv6:2607:f8b0:4864:20::330]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 248D23A096B for <oauth@ietf.org>; Wed, 6 May 2020 12:18:40 -0700 (PDT)
Received: by mail-ot1-x330.google.com with SMTP id j4so2306816otr.11 for <oauth@ietf.org>; Wed, 06 May 2020 12:18:39 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=udelt-no.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=ljdSHTFJ7iZFlZPAQJ/p5WIrGNa3odbQuRhNkRO0i/0=; b=brWSelPY3PiAyYBtHX6iIKkOoQwgQgin5DkfVXhQZVD8Q01PFXi8uIYaFX+bOjQYbY pBRwbz+/topo53/ACMFBZhrq0mkSr13w42xjnA+tvlzapcDtUcAk5X048fXJUVdLZk/1 s9lv4Cc2wndIuj2LTgeh3YxJMePMfsAz1uZ9RL9tdP9qVSYPcgbFjHD0lzHGULjxywiy 0rllFrBELlioBzIjK7IHHEhtlYipVBhqr6/ySd+wK2L8dWN+WdL6ZgfB+QlAdE6DOwcQ uHaS8kZanAmvVl+dkPCBbwfRuwZKWY5EZxfSMGKuI7WpmzC7Sb3pGYSUHEy2HRLtmE9S ctGQ==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=ljdSHTFJ7iZFlZPAQJ/p5WIrGNa3odbQuRhNkRO0i/0=; b=rbjYkFnLqfctkDrtZsKQdVedmv7FQeiPv6BCHuZ5zFX1B3hBdfprBcq+hcv2rZC8BO Jh4cuCFPhgyMGZzQf6wGBT/GKnQTmmUAGD7BZRPP/X88GoYnbm9LX/lSRCOB+cEMBAGa cCretdGMbN7T8ABRX0FCjCYlhxksX5k54saDzh6Xbc/K7P6DpoT/d60cmxjrHry7ZQor EPe+s7lmuTTsw5+sU1Z9SqFoobSJCzA/Lpq6b2PK3VQX8cpc9k/EaznZLa0VfQwBEb/V BaaB2DdXKZrVnMLNwHKHr/337XdzFmpDge5pkzGbkSjecBhGZUB1hquHMj9JQhDCdpzj rvlQ==
X-Gm-Message-State: AGi0PubVsy9WWhuh4Ab3dCtkB3ieXOyPHDZFX5NwVrO1pjU4hiioFxi7 KOe5rLfKMbLiIf1wvoKOCTZelre8/ZzDRX5f0tLjn9bATiQ=
X-Google-Smtp-Source: APiQypK8sp9yxhrj8A5OgBOsufA593G+B2CHJQdsUVUn+7JG/FuFj0apJn0/pDdRPZt9ZwNV45u/Oid7LfJur42LbjM=
X-Received: by 2002:a9d:7558:: with SMTP id b24mr7715388otl.273.1588792719066; Wed, 06 May 2020 12:18:39 -0700 (PDT)
MIME-Version: 1.0
References: <CAGBSGjrJRR-Anb4tcwGMELzV3d74pPP0WpBY8_Z00NYxfEp6gg@mail.gmail.com> <DFDFC45D-0EE6-40DF-8DCE-E81A29B8D448@independentid.com>
In-Reply-To: <DFDFC45D-0EE6-40DF-8DCE-E81A29B8D448@independentid.com>
From: Steinar Noem <steinar@udelt.no>
Date: Wed, 06 May 2020 21:18:28 +0200
Message-ID: <CAHsNOKda5M5TH2CzE_fc7hZJY2iBKmoNmF36QG9qbwR2pUGXsQ@mail.gmail.com>
To: Phillip Hunt <phil.hunt@independentid.com>
Cc: Aaron Parecki <aaron@parecki.com>, Mike Jones <Michael.Jones=40microsoft.com@dmarc.ietf.org>, "oauth@ietf.org" <oauth@ietf.org>
Content-Type: multipart/alternative; boundary="000000000000a466b505a4ffa165"
Archived-At: <https://mailarchive.ietf.org/arch/msg/oauth/2RCWsevR_UdXsjHpv8SPLiapllQ>
Subject: Re: [OAUTH-WG] OAuth 2.1 - require PKCE?
X-BeenThere: oauth@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: OAUTH WG <oauth.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/oauth>, <mailto:oauth-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/oauth/>
List-Post: <mailto:oauth@ietf.org>
List-Help: <mailto:oauth-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/oauth>, <mailto:oauth-request@ietf.org?subject=subscribe>
X-List-Received-Date: Wed, 06 May 2020 19:18:47 -0000

So, wouldn't a MUST just mean that we would have some OPs that are 2.1
compliant and some that aren't?

ons. 6. mai 2020 kl. 21:12 skrev Phillip Hunt <phil.hunt@independentid.com>:

> Mike,
>
> The point of 2.1 is to raise the security bar.
>
> Yes it adds new MUST requirements.
>
> But what about OIDC would break other than required implementation of PKCE
> to support 2.1?
>
> Eg Would additional signaling be required to facilitate interoperability
> and migration between versions? Would that be an oauth issue or an OIDC one?
>
> Phil
>
> On May 6, 2020, at 11:56 AM, Aaron Parecki <aaron@parecki.com> wrote:
>
> 
> > In particular, authorization servers shouldn’t be required to support
> PKCE when they already support the OpenID Connect nonce.
>
> The Security BCP already requires that ASs support PKCE:
> https://tools.ietf.org/html/draft-ietf-oauth-security-topics-15#section-2.1.1 Are
> you suggesting that the Security BCP change that requirement as well? If
> so, that's a discussion that needs to be had ASAP. If not, then that's an
> implicit statement that it's okay for OpenID Connect implementations to not
> be best-practice OAuth implementations. And if that's the case, then I also
> think it's acceptable that they are not complete OAuth 2.1 implementations
> either.
>
>
>
>
>
>
> On Wed, May 6, 2020 at 11:21 AM Mike Jones <Michael.Jones=
> 40microsoft.com@dmarc.ietf.org> wrote:
>
>> The disadvantage of requiring PKCE for OpenID Connect implementations is
>> that you’re trying to add a normative requirement that’s not required of
>> OpenID Connect deployments today, which would bifurcate the ecosystem.
>> There are hundreds of implementations (including the 141 certified ones at
>> https://openid.net/certification/), none of which have ever been
>> required to support PKCE.  Therefore, most don’t.
>>
>>
>>
>> Per feedback already provided, I believe that OAuth 2.1 should align with
>> the guidance already in the draft Security BCP, requiring EITHER the use of
>> PKCE or the OpenID Connect nonce.  Trying to retroactively impose
>> unnecessary requirements on existing deployments is unlikely to succeed and
>> will significantly reduce the relevance of the OAuth 2.1 effort.
>>
>>
>>
>> In particular, authorization servers shouldn’t be required to support
>> PKCE when they already support the OpenID Connect nonce.  And clients
>> shouldn’t reject responses from servers that don’t support PKCE when they
>> do contain the OpenID Connect nonce.  Doing so would unnecessarily break
>> things and create confusion in the marketplace.
>>
>>
>>
>>                                                           -- Mike
>>
>>
>>
>> *From:* OAuth <oauth-bounces@ietf.org> *On Behalf Of * Dick Hardt
>> *Sent:* Wednesday, May 6, 2020 10:48 AM
>> *To:* oauth@ietf.org
>> *Subject:* [OAUTH-WG] OAuth 2.1 - require PKCE?
>>
>>
>>
>> Hello!
>>
>>
>>
>> We would like to have PKCE be a MUST in OAuth 2.1 code flows. This is
>> best practice for OAuth 2.0. It is not common in OpenID Connect servers as
>> the nonce solves some of the issues that PKCE protects against. We think
>> that most OpenID Connect implementations also support OAuth 2.0, and
>> hence have support for PKCE if following best practices.
>>
>>
>>
>> The advantages or requiring PKCE are:
>>
>>
>>
>> - a simpler programming model across all OAuth applications and profiles
>> as they all use PKCE
>>
>>
>>
>> - reduced attack surface when using  S256 as a fingerprint of the
>> verifier is sent through the browser instead of the clear text value
>>
>>
>>
>> - enforcement by AS not client - makes it easier to handle for client
>> developers and AS can ensure the check is conducted
>>
>>
>>
>> What are disadvantages besides the potential impact to OpenID Connect
>> deployments? How significant is that impact?
>>
>>
>>
>> Dick, Aaron, and Torsten
>>
>>
>>
>> ᐧ
>> _______________________________________________
>> OAuth mailing list
>> OAuth@ietf.org
>> https://www.ietf.org/mailman/listinfo/oauth
>>
> _______________________________________________
> OAuth mailing list
> OAuth@ietf.org
> https://www.ietf.org/mailman/listinfo/oauth
>
> _______________________________________________
> OAuth mailing list
> OAuth@ietf.org
> https://www.ietf.org/mailman/listinfo/oauth
>


-- 
Vennlig hilsen

Steinar Noem
Partner Udelt AS
Systemutvikler

| steinar@udelt.no | hei@udelt.no  | +47 955 21 620 | www.udelt.no |