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Re: Presentation API in non secure contexts

From: Richard Barnes <rbarnes@mozilla.com>
Date: Mon, 23 Jan 2017 12:06:52 -0500
Message-ID: <CAOAcki-USzhqNYS1NqpQrz=QDbez=JGcFWqAdFr10h91Mxu8iA@mail.gmail.com>
To: Francois Daoust <fd@w3.org>
Cc: WebAppSec WG <public-webappsec@w3.org>, public-web-security@w3.org, "Kostiainen, Anssi" <anssi.kostiainen@intel.com>, "mark a. foltz" <mfoltz@google.com>
What is the rationale for why this API needs to be available to non-secure
contexts?

On Mon, Jan 23, 2017 at 12:00 PM, Francois Daoust <fd@w3.org> wrote:

> Dear Web App Security WG,
> [and Hello Web Security IG]
>
> The Presentation API allows an application to request display of web
> content onto a second screen. While the Presentation API forbids mixed
> content, it does not require a secure context. We discussed this point with
> some of you back at TPAC 2015 in Sapporo, and raised it in our request for
> review shortly afterwards:
> https://lists.w3.org/Archives/Public/public-webappsec/2015Nov/0064.html
>
> The feeling was that the overall risk is relatively low: there is
> permission involved and the API can do little harm to users.
>
> The Second Screen WG would like to confirm with you that this approach is
> still acceptable. The group received feedback that the spec should require
> secure contexts, especially because it prompts the user for permission. See
> discussion starting at:
> https://github.com/w3c/presentation-api/issues/362#issuecomment-262102686
>
> The security guidelines in the Presentation API were updated to highlight
> the need to warn users about origins that are potentially non trustworthy:
> https://w3c.github.io/presentation-api/#user-interface-guidelines
> ... and in particular:
> [[ Showing the origin that will be presented will help the user know if
> that content is from an potentially trustworthy origin (e.g., https:), and
> corresponds to a known or expected site. The user agent should specifically
> indicate when the origin requesting presentation is not potentially
> trustworthy. ]]
>
> As a side note, the Second Screen WG will soon re-publish another
> Candidate Recommendation of the Presentation API. On the security front,
> the only changes were to move the mixed content and sandboxing checks to
> the `PresentationRequest` constructor instead of to individual methods of
> the `PresentationRequest` object, to "fail early". We do not believe that
> this should trigger another security review, but feedback is of course
> always welcome!
>
> Thanks,
> Francois,
> Staff Contact, Second Screen WG.
>
>
>
Received on Monday, 23 January 2017 17:07:25 UTC

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