[Bug 23642] [security] Please require the relative-to-system-mixer sound volume model

https://www.w3.org/Bugs/Public/show_bug.cgi?id=23642

Xabier Rodríguez Calvar <calvaris@igalia.com> changed:

           What    |Removed                     |Added
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                 CC|                            |calvaris@igalia.com

--- Comment #1 from Xabier Rodríguez Calvar <calvaris@igalia.com> ---
(In reply to Alexander E. Patrakov from comment #0)
> The element's effective media volume is volume, interpreted relative to the
> range 0.0 to 1.0, with 0.0 being silent, and 1.0 being the loudest setting,
> values in between increasing in loudness. The range need not be linear. The
> loudest setting may be lower than the system's loudest possible setting; for
> example the user could have set a maximum volume."

> I think that the text needs to be clarified to rule out what I think is the
> deliberate misinterpretation currently done in Webkit-GTK on Linux,
> especially when the system runs PulseAudio in its default configuration with
> flat volumes. In fact, Xabier Rodríguez Calvar (a WebKit-GTK developer) has
> explicitly asked me to raise the issue with W3C during LinuxCon Europe 2013.

> The misinterpretation done by WebKit-GTK + PulseAudio is that the volume is
> interpreted as relative to the sound card's maximum hardware volume. I.e.,
> if the web page requests 100%, the master volume control of the system mixer
> will be bumped, resulting in a sound much louder than intended - potentially
> up to hardware or hearing damage. I think that it is a security issue to
> allow this behaviour, and thus want the wording to be changed in the
> standard.

> Of course, you are welcome to suggest a better wording that covers the
> issue. There may be other ways to produce audio from HTML5, they may need a
> similar clarification (requirement of a system-mixer-relative volume model)
> too.

Hi Alenxander, as we discussed at LinuxCon, I am happy that you made it here.
However I disagree with your interpretation as it lacks some POVs because you
give for granted certain concepts that are not granted like for example the
existance of a 'system volume' and if doesn't exist you want a method to set a
inviolable volume.

As I already told you a solution like this has many problems that you disregard
and that can't be just applied as you'd like. From my POV, WebKitGtk+ is ok as
it is now and complies with the standard, though I agree with you that there's
a  security issue with the volume and I think the problem is with the standard.

As it happens with for example when going to fullscreen, the browser should
raise a dialog before commiting the change when a webpage tries to set the
volume of an element through javascript.

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Received on Tuesday, 5 November 2013 11:33:32 UTC