[tbb-bugs] #30542 [Applications/Tor Browser]: pinch-to-zoom viewport vs other screen/window

[Tor Bug Tracker & Wiki]

#30542: pinch-to-zoom viewport vs other screen/window
-------------------------------------------------+-------------------------
 Reporter:  Thorin                               |          Owner:  tbb-
                                                 |  team
     Type:  defect                               |         Status:  new
 Priority:  Medium                               |      Milestone:
Component:  Applications/Tor Browser             |        Version:
 Severity:  Normal                               |     Resolution:
 Keywords:  tbb-fingerprinting, tbb-mobile,      |  Actual Points:
  tbb-parity                                     |
Parent ID:                                       |         Points:
 Reviewer:                                       |        Sponsor:
-------------------------------------------------+-------------------------
Description changed by gk:

Old description:

> I am not sure if this is an issue for TB. I do not have a touch device on
> which to install TB8. But since Tor Uplift's RFP underlines this
> protection, it might be prudent for someone to check it out.
>
> My Android has a low screen res, the web content loads at a higher res -
> when I pinch to zoom and re-run/refresh: the viewport shows entropy.
> Ignore the css media measurements. Just focus on the five JS results:
> screen, available screen, outer, inner and viewport
>
> Control
> - device should be hidpi/retina/whatever-you-call-it
> - load test page [1]
> - all the widths/heights (except viewport: e.g 17px less width) should be
> the same (i.e `1000 x 1000`)
> - zoom in to `133%`
> - refresh or rerun button
> - all the widths/heights (except viewport e.g 13px less width) should be
> the same (e.g `750 x 750`)
>
> STR
> - device should be hidpi
> - load the test page
> - all the widths/heights (except viewport) should be the same (e.g `980 x
> 1522`)
> - zoom in (fingers on a touch device)
> - scroll to the left and hit `re-run tests`
> - scroll back to the right and viewport is still based on the old value
> - also, in the pic in [2] css media still shows it's using the old values
> (`980`) (ignore that it's missing the height values: not sure why it does
> that: I think it's because it hits a fraction, I see the same thing on
> desktop)
>

> Is this just a quirk? Or is the viewport not properly spoofed in all
> situations?
>
> [1]
> https://ghacksuserjs.github.io/TorZillaPrint/TorZillaPrint.html#screen
> [2] https://github.com/ghacksuserjs/TorZillaPrint/issues/34

New description:

 I am not sure if this is an issue for TB. I do not have a touch device on
 which to install TB8. But since Tor Uplift's RFP underlines this
 protection, it might be prudent for someone to check it out.

 My Android has a low screen res, the web content loads at a higher res -
 when I pinch to zoom and re-run/refresh: the viewport shows entropy.
 Ignore the css media measurements. Just focus on the five JS results:
 screen, available screen, outer, inner and viewport

 Control
 - device should not be hidpi/retina/whatever-you-call-it
 - load test page [1]
 - all the widths/heights (except viewport: e.g 17px less width) should be
 the same (i.e `1000 x 1000`)
 - zoom in to `133%`
 - refresh or rerun button
 - all the widths/heights (except viewport e.g 13px less width) should be
 the same (e.g `750 x 750`)

 STR
 - device should be hidpi
 - load the test page
 - all the widths/heights (except viewport) should be the same (e.g `980 x
 1522`)
 - zoom in (fingers on a touch device)
 - scroll to the left and hit `re-run tests`
 - scroll back to the right and viewport is still based on the old value
 - also, in the pic in [2] css media still shows it's using the old values
 (`980`) (ignore that it's missing the height values: not sure why it does
 that: I think it's because it hits a fraction, I see the same thing on
 desktop)


 Is this just a quirk? Or is the viewport not properly spoofed in all
 situations?

 [1] https://ghacksuserjs.github.io/TorZillaPrint/TorZillaPrint.html#screen
 [2] https://github.com/ghacksuserjs/TorZillaPrint/issues/34

--

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/30542#comment:8>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online