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Re: [widgets] API - openURL security considerations

From: Adam Barth <w3c@adambarth.com>
Date: Mon, 8 Feb 2010 17:57:45 -0800
Message-ID: <7789133a1002081757w11514677v86ed6fcb80810df9@mail.gmail.com>
To: Marcos Caceres <marcosc@opera.com>
Cc: public-webapps <public-webapps@w3.org>
What about being about to link to file:// URLs?  You probably want to
ban that.  Also, have you considered what happens if you put a
JavaScript URL or a Data URL into openURL?


On Mon, Feb 8, 2010 at 8:36 AM, Marcos Caceres <marcosc@opera.com> wrote:
> At Opera we've been discussing some of the security implications around the
> openURL method in the widgets API spec. We think the spec might benefit if
> we were to add a non-normative security consideration section for openURL.
> We are basically concerned about protecting against a simple attack such as:
> while(true){
>  openURL("http://...");
> }
> The following text, which I did not write, can serve as a basis for the note
> - we are presenting it here for discussion, and you'll note it uses
> different terminology than the one found in the spec. In other words, please
> don't consider the following to be spec text, it needs a fair amount of
> editing but tries to get to the heart of the problem:
> [[
> APIs to open external programs, such as opening a URL in a browser, SHOULD
> only be allowed automatically if the widget has focus. Opening such an
> external program, SHOULD result in the widget losing focus, for the purpose
> of opening more external programs. User interaction with the widget may
> restore the focus to the widget. Widget Managers MAY offer a dialog for
> other attempts to open external programs, or MAY fail the operation. User
> agents MAY also offer an override for users to allow a widget to open
> external programs automatically, even when minimized in the background.
> Security considerations: Widgets may have managed run-time constraints, for
> instance on memory usage or domain access, and opening multiple instances of
> external programs may easily exceed those constraints. External programs may
> present dialogs to perform harmful actions, e.g. download dialogs, and
> multiple new windows in a short time span may allow for interaction flooding
> attacks or may lead to warning fatigue. This security measure ensures that
> users get a reasonable chance to manage the run-time constraints, and
> ensures that only one external program and/or dialog can be opened at a
> time.
> See http://www.w3.org/TR/wsc-ui/#popups for more details.
> ]]
> We would appreciate any feedback people have about the proposed text.
Received on Tuesday, 9 February 2010 01:58:39 UTC

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