1306422 - [webvr] VRDisplay.exitPresent must only be allowed by content that started VR Presentation

Status: RESOLVED FIXED

(Core :: Graphics, defect)

Description

[:kip (Kearwood Gilbert)]

In our current WebVR implementation, VRDisplay.exitPresent can be called by any Javascript, even if it is in a different tab or window that did not start the VR Presentation.

This could enable erroneous or malicious scripts to interrupt a VR Session and replace the VR session with their own, taking over the user's headset.

VRDisplay.exitPresent should not succeed unless it is called from the same Javascript context that successfully created a VR session with VRDisplay.requestPresent

Comment 1

[:kip (Kearwood Gilbert)]

The VRDisplay.exitPresent was correctly preventing other content from exiting VR presentation; however, in this case, the returned promise was still resolving successful.

Comment 2

[:kip (Kearwood Gilbert)]

While fixing the VRDisplay.exitPresent to resolve fail its returned promise, I noticed that VRDisplay.isPresenting is returning the global state of the VRDisplay.  I have updated this as well in the patch so that the isPresenting attribute only returns true for VR presentations started within the same Javascript context.

Comment 3

[:kip (Kearwood Gilbert)]

Attachment: Bug 1306422 - VRDisplay.exitPresent must only be allowed by content that started VR Presentation

- While fixing the VRDisplay.exitPresent to resolve fail its returned
  promise, I noticed that VRDisplay.isPresenting is returning the global
  state of the VRDisplay.  I have updated this as well in the patch so
  that the isPresenting attribute only returns true for VR presentations
  started within the same Javascript context.

Review commit: https://reviewboard.mozilla.org/r/82232/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/82232/

Comment 4

[George Wright (:gw280) (needinfo me!)]

Comment on attachment 8796356 [details]
Bug 1306422 - VRDisplay.exitPresent must only be allowed by content that started VR Presentation

https://reviewboard.mozilla.org/r/82232/#review83478

::: dom/vr/VRDisplay.cpp:652
(Diff revision 1)
>  
>  bool
>  VRDisplay::IsPresenting() const
>  {
> -  return mClient->GetIsPresenting();
> +  // IsPresenting returns true only if this Javascript context is presenting
> +  // and will return false if another context is presenting.

I would rather have method behaviour docs like this in the header file, where the method is declared.

Comment 5

[George Wright (:gw280) (needinfo me!)]

Comment on attachment 8796356 [details]
Bug 1306422 - VRDisplay.exitPresent must only be allowed by content that started VR Presentation

https://reviewboard.mozilla.org/r/82232/#review83482

Comment 6

[:kip (Kearwood Gilbert)]

https://hg.mozilla.org/integration/mozilla-inbound/rev/2a503541609be3dffe938480a256117690d90222
Bug 1306422 - VRDisplay.exitPresent must only be allowed by content that started VR Presentation,r=gwright

Comment 7

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/2a503541609b