665598 - Pref to disable Audio API

Status: RESOLVED FIXED

(Core :: Audio/Video, enhancement)

Description

[al_9x]

User-Agent:       Mozilla/5.0 (Windows NT 5.1; rv:2.0.1) Gecko/20100101 Firefox/4.0.1
Build Identifier: 

DOM based audio and video as well as the DOMless audio API extension make possible unsolicited, surprising, unwelcome, annoying media playback from any website.  This is particularly problematic for audio, but video can be pretty annoying as well and also consume a lot more resources, particularly the cpu, all without user consent.

It also increases the attack surface area of the browser, as most serious exploits involve JS + some API.  Audio/video decoding/rendering is complex and no doubt has exploitable bugs.

If the user does not want to be annoyed by media or for security hardening purposes it should be possible to complete disable this whole subsystem.  Ideally it should be possible to white list sites or pages, but as a first step at least a single global pref should be created.


Reproducible: Always

Comment 2

[al_9x]

This is not a dupe.  This bug is specifically about the disabling of the html5 <audio> <video> tags/elements/objects.  Bug 24418 is about some vague generic solution to blocking all video/audio which will never be addressed.

Comment 3

[Jo Hermans]

Whatever, suit yourself. Ok, most bugs that are duped against it, are only interested in muting all sounds, but it's also the implementation of <http://www.w3.org/WAI/UA/WAI-USERAGENT/>. And that's what counts.

Comment 4

[Stephan Sokolow]

As a workaround, you could use NoScript with whitelisting of everything except audio/video tags turned off.

Comment 5

[Chris Pearce [:cpearce (Not reading bugmail)]]

You can set the media.webm.enabled, media.ogg.enabled and media.wave.enabled prefs to false to render <video> and <audio> elements unable to play anything.

Comment 6

[al_9x]

(In reply to Chris Pearce (:cpearce) from comment #5)
> You can set the media.webm.enabled, media.ogg.enabled and media.wave.enabled
> prefs to false to render <video> and <audio> elements unable to play
> anything.

I don't think these prefs apply to the audio API extension.

Comment 7

[Chris Pearce [:cpearce (Not reading bugmail)]]

So to be clear, what we want here is a new pref to disable the AudioAPI, as we've already got prefs to disable ogg,wave, and webm in HTML5 audio/video.

So the idea is to not actually disable <audio>,<video> or the AudioAPI by default, but to provide the option to disable it so that people can choose to disable it, similar to how people have the option to use flashblock to disable Flash.

Comment 8

[Chris DeCairos (:cade)]

So just to be certain here, we need a patch that disables writing Audio data via mozWriteAudio?

Comment 9

[Chris Pearce [:cpearce (Not reading bugmail)]]

Yes. The pref should prevent JavaScript from being able to generate sound using the Audio API.

Comment 10

[David Humphrey (:humph)]

(In reply to Chris DeCairos (:cadecairos) from comment #8)
> So just to be certain here, we need a patch that disables writing Audio data
> via mozWriteAudio?

You probably just want to refuse to create the audio stream in mozSetup, see http://mxr.mozilla.org/mozilla-central/source/content/html/content/src/nsHTMLAudioElement.cpp#155

Comment 11

[Chris DeCairos (:cade)]

Attachment: Adds media.audio_api_enabled pref

This patch will stop all writing of audio though JavaScript. I tested it using this link here: http://static.bocoup.com/core/code/firefox-audio/html-sings/audio-out-music-gen-f1lt3r.html

I'm concerned about if it's toggled on and off while audio is being written, but I can't say if that's a case we need to worry about ( The script will just throw JS errors because it can't write any more data.)

Comment 12

[Phoenix]

Why this was not checked in?

Comment 13

[Matthew Gregan [:kinetik]]

Attachment: patch v1

The original patch no longer applies.  In rebasing it, I've made some small changes:
- Isolate IsAudioAPIEnabled in nsHTMLAudioElement.cpp
- Rename the pref so that it's distinct from the Web Audio API.
- Return an error rather than NS_OK when the API is disabled.

Comment 14

[Chris Pearce [:cpearce (Not reading bugmail)]]

Comment on attachment 713778 [details] [diff] [review]
patch v1

Review of attachment 713778 [details] [diff] [review]:
-----------------------------------------------------------------

Sorry, this slipped of my radar!

::: content/html/content/src/nsHTMLAudioElement.cpp
@@ +22,5 @@
>  
> +namespace {
> +
> +bool
> +IsAudioAPIEnabled()

"We prefer using 'static' instead of anonymous C++ namespaces."

https://developer.mozilla.org/en-US/docs/Developer_Guide/Coding_Style#Anonymous_namespaces

Comment 15

[Matthew Gregan [:kinetik]]

Fixed the namespace thing, and pushed:

https://hg.mozilla.org/integration/mozilla-inbound/rev/80d52655c8b8

Comment 16

[Ed Morley [:emorley]]

https://hg.mozilla.org/mozilla-central/rev/80d52655c8b8

Comment 17

[Chris DeCairos (:cade)]

Apologies for letting that slip through the cracks.. thanks for cleaning it up and getting it landed!

Comment 18

[JOHAN OLIVER]

hEY, THIS IS NOT FIXED. THEY ARE AUDIO FINGERPRINTING US BECAUSE THIS OPTION FROM 2013 WAS REMOVED