- From: Harry Halpin <hhalpin@w3.org>
- Date: Tue, 16 Aug 2016 19:49:54 +0200
- To: Mark Watson <watsonm@netflix.com>
- Cc: David Singer <singer@apple.com>, Paul Cotton <Paul.Cotton@microsoft.com>, "public-html-media@w3.org" <public-html-media@w3.org>
- Message-ID: <2d49595a-8699-e4c3-3b03-922a5dffdc12@w3.org>
On 08/16/2016 07:46 PM, Mark Watson wrote: > > > On Tue, Aug 16, 2016 at 10:36 AM, Harry Halpin <hhalpin@w3.org > <mailto:hhalpin@w3.org>> wrote: > > > > On 08/16/2016 07:28 PM, David Singer wrote: > >> On Aug 16, 2016, at 10:22 , Harry Halpin <hhalpin@w3.org > <mailto:hhalpin@w3.org>> wrote: > >> > >> > >> > >> On 08/16/2016 06:35 PM, David Singer wrote: > >>> I think you’ll need to explain why the choice of how much, and > how, the user is warned, needs to be made by you/us, and not by > the browser maker. You also haven’t given details of the ‘user > harm’ you talk about for EME itself. > >> The details of 'user harm' are adequately explained by the > concerns over > >> the DMCA and the use of DRM that have been well-documented > elsewhere > >> [1]. > > No, those criticisms were almost exclusively focused on the risk > to security researchers. Not one of the sub-headings you link to > appears to apply to users. Current politics notwithstanding, > repeatedly stating something doesn’t intrinsically make it true. > > I don't agree. Insofar as security researchers cannot audit the > security of DRM systems, then it is *users* who will face any harm due > to the lack of security audits. That is a unique feature of DRM > that EME > enables. EME can also, due to clearkey, be considered a DMCA-compliant > system itself (i.e. clearKey's Key System is equivalent to a CDM). > > > > >> Any installation or use of software that is compliant with the DMCA > >> can be considered a risk to users and security researchers as > is noted > >> on WIkipedia [1]. > > Users and security researchers are not the same people. > > See above. > > > > >> Although the FO is filed as an individual, one task of W3C is > to assure > >> there is representation of the interest of users and to ensure > the Web > >> is secure. > > Sure, but you need to say what the *user* harm is. > > If there is a part of a browser that makes security research difficult > and possibly illegal, then that part of the browser is rather > self-evidently dangerous to end-users. > > > Unless the browser implementor takes additional measures to > compensate for that difficulty / possible illegality. I really do appreciate the work by this WG to compensate, but I do not think they are sufficient without 'off by default.' We can agree to disagree here, and let the WG make a decision and pass it to the Director. In that case, the FO still stands. > > > While I appreciate the effort, > sandboxing may help but there is no such thing as a perfect sandbox. > > > There is no such thing as a perfect security audit either. We're > talking about different kinds of risk reduction. > Agreed. However, the DMCA provides a 'chilling effect' on security audits and research on DRM systems in general, regardless of the particular details of an audit or research. > > > > >> So, I think the decision should be made by the Working Group > >> with the best interests of users in mind, not just the browser > makers. > >> While you can consider 'off by default' to be unreasonable, I > think if > >> one takes that this same approach has been adopted by similarly > >> controversial APIs (Geolocation API), I think it's quite > reasonable. > >> > >> cheers, > >> harry > >> > >> [1] > >> > https://en.wikipedia.org/wiki/Digital_Millennium_Copyright_Act#Criticisms > <https://en.wikipedia.org/wiki/Digital_Millennium_Copyright_Act#Criticisms> > >> > >>> > >>>> On Aug 16, 2016, at 4:28 , Harry Halpin <hhalpin@w3.org > <mailto:hhalpin@w3.org>> wrote: > >>>> > >>>> > >>>> > >>>> On 08/13/2016 05:05 PM, Paul Cotton wrote: > >>>>> Note that I am responding to an email and proposal from > Harry from earlier in this thread. > >>>>> > https://lists.w3.org/Archives/Public/public-html-media/2016Aug/0005.html > <https://lists.w3.org/Archives/Public/public-html-media/2016Aug/0005.html> > >>>>> > >>>>>> The text I would add to the EME spec would be similar: > >>>>>> "A conforming implementation of this specification MUST > ensure that this > >>>>>> API cannot be used without the user's express permission > due to the > >>>>>> inherent risks in the activation of a CDM in a user agent. > The API MUST > >>>>>> be disabled by default, and should only be activated when > the user gives > >>>>>> express consent and is fully informed on a per-origin basis." > >>>>> This request would appear to be (at least partially) covered > by the existing text in the EME CR: > >>>>> > http://www.w3.org/TR/encrypted-media/#navigator-extension-requestmediakeysystemaccess > <http://www.w3.org/TR/encrypted-media/#navigator-extension-requestmediakeysystemaccess> > >>>>> > >>>>> 3.1.1 Methods > >>>>> requestMediaKeySystemAccess > >>>>> Note > >>>>> > >>>>> Calling this method may have user-visible effects, including > requests for user consent. This method should only be called when > the author intends to create and use a MediaKeys object with the > provided configuration. > >>>>> Requests access to the specified Key System. When > supportedConfigurations is specified, the configuration specified > by at least one of its elements must be supported. The resulting > MediaKeySystemAccess will correspond to the first such element. > >>>>> Any permission checks or user interaction, such as a prompt, > MUST be performed before resolving the promise. > >>>>> Were you aware of this text in the EME specification? Can > you live with the current text since changing this text to be > normative and changing it to a MUST (I believe) would be a > “breaking change” and would require that we re-publish another EME CR? > >>>>> > >>>>> /paulc > >>>>> HME WG Chair > >>>> Paul, > >>>> > >>>> Thanks for noting 'use-visible effects' but it does not > either explicitly 1) require a user-visible effect for fully > informing the user" and "gaining their consent" as well "turning > off EME by default". Simply put, the text you are noting says MAY > have user-visible effects and as so is too weak to include in a > test-suite or support EME being off by default. So, it does not > cover my objection, which normatively requires much stronger text, > including "off by default". So, no I can't live with that text and > require the change (or a semantically equivalent one) that I > suggest in the github repo and e-mail list: > >>>> > >>>> https://github.com/w3c/encrypted-media/issues/304 > <https://github.com/w3c/encrypted-media/issues/304> > >>>> > >>>> Thus, my formal objection still stands. > >>>> > >>>> cheers, > >>>> harry > >>>> > >>>>> > >>>>> From: Harry Halpin [mailto:hhalpin@w3.org > <mailto:hhalpin@w3.org>] > >>>>> Sent: Tuesday, August 2, 2016 5:00 AM > >>>>> To: public-html-media@w3.org <mailto:public-html-media@w3.org> > >>>>> Subject: Re: Formal objection to Encrypted Media Extensions > progressing to Proposed Recommendation without greater user protection > >>>>> > >>>>> > >>>>> > >>>>> > >>>>> On 08/02/2016 03:00 AM, Paul Cotton wrote: > >>>>>> An individual who registers a Formal Objection should cite > technical arguments and propose changes that would remove the > Formal Objection; > >>>>> > http://www.w3.org/2015/Process-20150901/#WGArchiveMinorityViews > <http://www.w3.org/2015/Process-20150901/#WGArchiveMinorityViews> > >>>>> > >>>>> Before I record your formal objection at [1] I would like to > ensure that your “proposed change” for your objection is understood. > >>>>>> There is prior art in HTML for similarly powerful and > privacy-invasive features such as the Geolocation API [4]. Thus, > there should be no procedural problem in requiring user consent > and disabling EME by default in all browsers. > >>>>> The reference you provide as a “prior art” precedent in [4] > is in a non-normative section of Geolocation API and it does NOT > disable the Geolocation API by default. Can you explain why you > think this reference is useful here? Are you suggesting similar > text be added to EME? If so could you suggest exact text that > would remove your formal objection? > >>>>> > >>>>> The exact phrasing is " A conforming implementation of this > specification must provide a mechanism that protects the user's > privacy and this mechanism should ensure that no location > information is made available through this API without the user's > express permission" > >>>>> > >>>>> To clarify, I agree that the spec should have used > capitalization: " A conforming implementation of this > specification MUST provide a mechanism that protects the user's > privacy and this mechanism should ensure that no location > information is made available through this API without the user's > express permission." > >>>>> > >>>>> However, I do believe that all browsers *do* indeed ask for > user consent before using the Geolocation API and that it is > disabled by default, which is clear prior art for EME. This is > indeed the case on the browsers I use, but if others activate > Geolocation API without user consent, please do inform me, as I > don't use Microsoft products. > >>>>> > >>>>> The text I would add to the EME spec would be similar: > >>>>> > >>>>> "A conforming implementation of this specification MUST > ensure that this API cannot be used without the user's express > permission due to the inherent risks in the activation of a CDM in > a user agent. The API MUST be disabled by default, and should only > be activated when the user gives express consent and is fully > informed on a per-origin basis." > >>>>> > >>>>> Given there is already a place where user consent MUST be > asked in the EME spec (" User agents must ensure that users are > fully informed and/or give explicit consent before Distinctive > Identifier(s) are exposed, such as in messages from the Key System > implementation"), there is no reason why this MUST can't be > broadened. I would also remove the "or." The user must be fully > informed AND give explicit consent. > >>>>> > >>>>> Furthermore, given this normative, testing for express user > consent on a per-origin basis should be part of the test-suite. > >>>>> > >>>>> cheers, > >>>>> harry > >>>>> > >>>>> > >>>>> > >>>>> > >>>>> > >>>>> /paulc > >>>>> HME WG Chair > >>>>> > >>>>> [1] > https://dev.w3.org/html5/status/formal-objection-status.html > <https://dev.w3.org/html5/status/formal-objection-status.html> > >>>>> > >>>>> From: Harry Halpin [mailto:hhalpin@w3.org > <mailto:hhalpin@w3.org>] > >>>>> Sent: Monday, August 1, 2016 6:42 PM > >>>>> To: public-html-media@w3.org <mailto:public-html-media@w3.org> > >>>>> Subject: Formal objection to Encrypted Media Extensions > progressing to Proposed Recommendation without greater user protection > >>>>> > >>>>> [Note this is a formal objection as an individual in a > private capacity, not on behalf of my organization] > >>>>> > >>>>> I'd like to fill a formal objection against Encrypted Media > Extensions progressing to Proposed Recommendation status without > adequate protection for users. > >>>>> > >>>>> I believe that this work is so problematic given the > well-known and well-documented problems with DRM, it should not > happen as a standard at all at W3C. That being said, for reasons > which I do not agree with and hope he reconsiders, the Director > has approved both the scope of the charter and the move of the > Working Draft to Candidate Recommendation. > >>>>> > >>>>> If it does happen, then it seems given the well-documented > problems, some harm mitigation should be pursued. The security > research community has broad support for the EFF covenant being a > normative requirement [1]. However, it appears consensus is not > forthcoming on either EME itself or the EFF covenant, with the > Technology and Policy IG also failing to gain any consensus for > even further discussion (as it failed to even get chartered). > >>>>> > >>>>> To myself, the danger of EME is that over the last year > suddenly over millions of people had a content decryption module > installed without their explicit consent on their computer. For > many users, such as those of Firefox, the DCM was installed via a > silent update they had no control over. Such a content decryption > module can serve as both a technical security risk, as it puts a > highly privileged process in the user's computer outside their > direct control by design, and as a legal risk subjects any > inspection of the DRM-enabled system on their computer due to the > anti-circumvention provision of the DMCA or local equivalent. > Thus, regardless of whether or not one agrees with EME, it seems > the *least* the W3C should do is warn the user about the > installation and activation of a CDM on their machine - and that > the CDM should not be installed and EME should not be activated > without explicit user consent. Thus, in all configurations, EME > should be *de-activated by default.* > >>>>> > >>>>> There is prior art in HTML for similarly powerful and > privacy-invasive features such as the Geolocation API [4]. Thus, > there should be no procedural problem in requiring user consent > and disabling EME by default in all browsers. While it can be > argued many users will want to watch protected videos and will > turn them on, just as many users will want to use Google Maps with > Geolocation APIs, there does not seem to be a reasonable case for > having such > >>>>> powerful and possibly dangerous features enabled by default. > >>>>> > >>>>> Current language in the spec is so weak as it may not be > enforced and so EME does not have to be disabled by default: " > User Agents have some flexibility to determine whether consent is > required for a specific configuration and whether such consent may > also apply to other configurations. For example, consent to one > configuration may also imply consent for less powerful, more > restricted configurations. Equally, a denial of consent for one > configuration may imply denial of consent for more powerful, less > restricted configurations." > >>>>> > >>>>> The only place where the spec [5] makes normative statements > around consent, but due to how DRM (i.e. Key Systems) are > designed, it is unclear how the user agent should interpret these > statements > >>>>> > >>>>> "If a user agent chooses to support a Key System > implementation that cannot be sufficiently sandboxed or otherwise > secured, the user agent should ensure that users are fully > informed and/or give explicit consent before loading or invoking it." > >>>>> > >>>>> "User Agents should ensure that users are fully informed > and/or give explicit consent before a Key System that presents > security concerns that are greater than other user agent features > (e.g. DOM content) may be accessed by an origin..." > >>>>> > >>>>> " User agents must ensure that users are fully informed > and/or give explicit consent before Distinctive Identifier(s) are > exposed, such as in messages from the Key System implementation." > >>>>> > >>>>> Although these statements show some progress towards trying > to mitigate the dangers of DRM, given that DRM systems work in > conjunction with anti-circumvention legislation that prevents a > developer from knowing whether or not they can sufficiently > sandboxed (or 'otherwise secured') and whether a Distinctive > Identifier is used by the DRM system, so the use of EME will > *always* present security concerns that are greater than the rest > of the user agent features involving the Open Web Platform. > >>>>> > >>>>> Is the Working Group amendable to having EME and associated > DRM systems (i.e. "Key Systems") *normatively* disabled by default > in order to protect users? > >>>>> > >>>>> cheers, > >>>>> harry > >>>>> > >>>>> [1] > https://www.eff.org/deeplinks/2016/03/security-researchers-tell-w3c-protect-researchers-who-investigate-browsers > <https://www.eff.org/deeplinks/2016/03/security-researchers-tell-w3c-protect-researchers-who-investigate-browsers> > >>>>> [2] > https://en.wikipedia.org/wiki/Digital_rights_management#Opposition_to_DRM > <https://en.wikipedia.org/wiki/Digital_rights_management#Opposition_to_DRM> > >>>>> [3] > https://en.wikipedia.org/wiki/Digital_rights_management#Shortcomings > <https://en.wikipedia.org/wiki/Digital_rights_management#Shortcomings> > >>>>> [4] > https://www.w3.org/TR/geolocation-API/#implementation_considerations > <https://www.w3.org/TR/geolocation-API/#implementation_considerations> > >>>>> [5] https://w3c.github.io/encrypted-media/ > <https://w3c.github.io/encrypted-media/> > >>>>> > >>> David Singer > >>> Manager, Software Standards, Apple Inc. > >>> > >> > >> > > David Singer > > Manager, Software Standards, Apple Inc. > > > > >
Received on Tuesday, 16 August 2016 17:50:33 UTC