Return-Path: X-Original-To: jose@ietfa.amsl.com Delivered-To: jose@ietfa.amsl.com Received: from localhost (ietfa.amsl.com [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id CD99C1A03E3 for ; Mon, 20 Oct 2014 08:57:12 -0700 (PDT) X-Virus-Scanned: amavisd-new at amsl.com X-Spam-Flag: NO X-Spam-Score: -1.977 X-Spam-Level: X-Spam-Status: No, score=-1.977 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, FM_FORGED_GMAIL=0.622, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_LOW=-0.7] autolearn=unavailable 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 pE4v63KkXdRL for ; Mon, 20 Oct 2014 08:57:11 -0700 (PDT) Received: from mail-vc0-f179.google.com (mail-vc0-f179.google.com [209.85.220.179]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id D27301A01F9 for ; Mon, 20 Oct 2014 08:56:00 -0700 (PDT) Received: by mail-vc0-f179.google.com with SMTP id im17so3803018vcb.10 for ; Mon, 20 Oct 2014 08:55:58 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:date :message-id:subject:from:to:cc:content-type; bh=arR8Dm6LKSOnGspnV1iAu6YWUJv0eF2HnBUIykm1GA8=; b=DTTPkERLXyXioVc/nrTIIPF72T2sEjfRh0AD90nH5RazJlhL+sFVyqF51P8sSakENv YsuHOWYari1+g7v63aViRlxLK7RX3KvY8xDeapmKSRc/wkM3zsznv8T0KtEmiJ6P0JQ5 KIuSoPtMQYMoPGZoMu4EGVlmaOezkTLXg4euKTUOjCnNCqGEPSsG6kLup+cIDqAZ7ioo l1D0olhH2xLjhCQTMLlgXXyrKDvVBTXLClYfBCEojgtW34CII6GqZT+73ystyXMdDDTd MVKDKPo49adp3nIzcksPtp8EJTscj1WaFzqZ/jOIjefuNH/gPmE/YPiTiZ4TCeWeyT0n zhJA== X-Gm-Message-State: ALoCoQmsurao16wHwQRv3RNqOttxJ6jNrQRvMgnZX0J/wSY0AtvJvKDS5sbtiABWvEzKwbsVTMQC MIME-Version: 1.0 X-Received: by 10.52.233.164 with SMTP id tx4mr1814798vdc.65.1413820139260; Mon, 20 Oct 2014 08:48:59 -0700 (PDT) Received: by 10.31.149.205 with HTTP; Mon, 20 Oct 2014 08:48:59 -0700 (PDT) In-Reply-To: <4E1F6AAD24975D4BA5B16804296739439BB18E4B@TK5EX14MBXC286.redmond.corp.microsoft.com> References: <20141002023617.18602.69709.idtracker@ietfa.amsl.com> <4E1F6AAD24975D4BA5B16804296739439BAF0C49@TK5EX14MBXC286.redmond.corp.microsoft.com> <4E1F6AAD24975D4BA5B16804296739439BAFACA8@TK5EX14MBXC286.redmond.corp.microsoft.com> <4E1F6AAD24975D4BA5B16804296739439BB18E4B@TK5EX14MBXC286.redmond.corp.microsoft.com> Date: Mon, 20 Oct 2014 11:48:59 -0400 Message-ID: From: Richard Barnes To: Mike Jones Content-Type: multipart/alternative; boundary=089e011849c42d5da20505dca7f3 Archived-At: http://mailarchive.ietf.org/arch/msg/jose/FK9-W-kObjxMHQIIKCvbskJoFw8 Cc: "jose-chairs@tools.ietf.org" , "jose@ietf.org" , The IESG , "draft-ietf-jose-json-web-algorithms@tools.ietf.org" Subject: Re: [jose] Richard Barnes' Discuss on draft-ietf-jose-json-web-algorithms-33: (with DISCUSS and COMMENT) X-BeenThere: jose@ietf.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Javascript Object Signing and Encryption List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 20 Oct 2014 15:57:13 -0000 --089e011849c42d5da20505dca7f3 Content-Type: text/plain; charset=UTF-8 On Sat, Oct 18, 2014 at 7:09 PM, Mike Jones wrote: > > > > Section 3.6. > > > > I'm not going to object to "none", even though I think it's a very > dangerous > > > > feature because of the risk of confusion between Secured and > Unsecured JWS. > > > > But there needs to be stronger guidance: > > > > 1. An implementation SHOULD NOT support "none" unless the implementer > > > > knows that it will be used in application context s that require it. > > > > 2. If an implementation does support "none", then it MUST NOT accept > it as part > > > > of generic JWS validation. Instead, it should require the > application to explicitly > > > > signal that an Unsecured JWS is expected for a given validation > operation. > > > > > > As discussed in the working group, your concern about applications > inappropriately allowing the use of "none" actually is an instance of a > more general concern that applications not allow *any* algorithms to be > used that are not appropriate in their application contexts. This concern > is already addressed in the specification at the end of Section 5.2 as > follows: > > > > > > "Finally, note that it is an application decision which algorithms are > acceptable in a given context. Even if a JWS can be successfully validated, > unless the algorithm(s) used in the JWS are acceptable to the application, > it SHOULD reject the JWS." > > > > > > Since your specific concern is already handled in a more general way, > I would like to request that you withdraw this DISCUSS on that basis. > Also, you were one of the contributing authors to the security > considerations on this topic in Section 8.5 of JWA (Unsecured JWS Security > Considerations), so it's not clear that there's any cause for you to come > back with additional wording change requests on this topic at this point. > > > > > > Thanks for reminding me about Section 8.5. I think I would be > satisfied here if the contents of Section 8.5 were just moved up to this > section. That way all of the requirements for implementing "none" will be > together. > > > > Section 3.6 does end with the sentence "See Section 8.5 for security > considerations associated with using this algorithm" so implementers are > reminded to also pay attention to the security considerations. If we were > to do what you requested, this would be the only algorithm for which the > security considerations were included in the algorithm description, rather > than in the security considerations section, which would be fairly weird > and non-parallel, editorially. > > > > Actually, "none" is the only algorithm for which there are additional > normative requirements in the Security Considerations. So it actually > seems more sensible to move those requirements up. > > I'm really just asking for a copy/paste here, shouldn't be invasive. > But I do think the level of indirection creates security risk. > > I'm OK moving up the three sentences that actually do contain normative > requirements. Those are: > > Implementations that support Unsecured JWS objects MUST NOT accept > such objects as valid unless the application specifies that it is > acceptable for a specific object to not be integrity-protected. > Implementations MUST NOT accept Unsecured JWS objects by default. > In order to mitigate downgrade attacks, applications MUST NOT signal > acceptance of Unsecured JWS objects at a global level, and SHOULD > signal acceptance on a per-object basis. > > I'm not OK cluttering up the normative description of the algorithm with > the discussion text. Assuming you're OK leaving the discussion text and > "for example" text in 8.5, I think we have a way forward on this one. > Please let me know if that works for you. > Sounds fine to me. Thanks for the compromise. --Richard > > Again, given that you were an author of 8.5 and seemed fine with the > resolution after the extensive discussion then, I'd ask you to clear the > DISCUSS on that basis and not request that it be reworked again. > > -- Mike > > --089e011849c42d5da20505dca7f3 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable


On Sat, Oct 18, 2014 at 7:09 PM, Mike Jones <Michael.Jones@m= icrosoft.com> wrote:
> > > Section 3.6.
> > > I'm not going to object to "none", even though= I think it's a very dangerous
> > > feature because of the risk of confusion between Secured and= Unsecured JWS.
> > > But there needs to be stronger guidance:
> > > 1. An implementation SHOULD NOT support "none" unl= ess the implementer
> > > knows that it will be used in application context s that req= uire it.
> > > 2. If an implementation does support "none", then = it MUST NOT accept it as part
> > > of generic JWS validation.=C2=A0 Instead, it should require = the application to explicitly
> > > signal that an Unsecured JWS is expected for a given validat= ion operation.
> >
> > As discussed in the working group, your concern about application= s inappropriately allowing the use of "none" actually is an insta= nce of a more general concern that applications not allow *any* algorithms = to be used that are not appropriate in their application contexts.=C2=A0 Th= is concern is already addressed in the specification at the end of Section = 5.2 as follows:
> >
> > "Finally, note that it is an application decision which algo= rithms are acceptable in a given context. Even if a JWS can be successfully= validated, unless the algorithm(s) used in the JWS are acceptable to the a= pplication, it SHOULD reject the JWS."
> >
> > Since your specific concern is already handled in a more general = way, I would like to request that you withdraw this DISCUSS on that basis.= =C2=A0 Also, you were one of the contributing authors to the security consi= derations on this topic in Section 8.5 of JWA (Unsecured JWS Security Consi= derations), so it's not clear that there's any cause for you to com= e back with additional wording change requests on this topic at this point.=
> >
> > Thanks for reminding me about Section 8.5.=C2=A0 I think I would = be satisfied here if the contents of Section 8.5 were just moved up to this= section.=C2=A0 That way all of the requirements for implementing "non= e" will be together.
>
> Section 3.6 does end with the sentence "See Section 8.5 for secur= ity considerations associated with using this algorithm" so implemente= rs are reminded to also pay attention to the security considerations.=C2=A0= If we were to do what you requested, this would be the only algorithm for = which the security considerations were included in the algorithm descriptio= n, rather than in the security considerations section, which would be fairl= y weird and non-parallel, editorially.
>
> Actually, "none" is the only algorithm for which there are a= dditional normative requirements in the Security Considerations.=C2=A0 So i= t actually seems more sensible to move those requirements up.
> I'm really just asking for a copy/paste here, shouldn't be inv= asive.=C2=A0 But I do think the level of indirection creates security risk.=

I'm OK moving up the three sentences that actually do contain no= rmative requirements.=C2=A0 Those are:

=C2=A0 =C2=A0Implementations that support Unsecured JWS objects MUST NOT ac= cept
=C2=A0 =C2=A0such objects as valid unless the application specifies that it= is
=C2=A0 =C2=A0acceptable for a specific object to not be integrity-protected= .
=C2=A0 =C2=A0Implementations MUST NOT accept Unsecured JWS objects by defau= lt.
=C2=A0 =C2=A0In order to mitigate downgrade attacks, applications MUST NOT = signal
=C2=A0 =C2=A0acceptance of Unsecured JWS objects at a global level, and SHO= ULD
=C2=A0 =C2=A0signal acceptance on a per-object basis.

I'm not OK cluttering up the normative description of the algorithm wit= h the discussion text.=C2=A0 Assuming you're OK leaving the discussion = text and "for example" text in 8.5, I think we have a way forward= on this one.=C2=A0 Please let me know if that works for you.

= Sounds fine to me.=C2=A0 Thanks for the compromise.

--Ric= hard

=C2=A0
> Again, given that you were an author of 8.5 and seemed fine with the r= esolution after the extensive discussion then, I'd ask you to clear the= DISCUSS on that basis and not request that it be reworked again.

=C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 -- Mike


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