[libvirt] Do different Virgil3D users running have the same CANVAS fingerprint?
bancfc at openmailbox.org
bancfc at openmailbox.org
Wed Jan 11 04:34:45 UTC 2017
ACK :)
On 2017-01-09 11:17, Martin Kletzander wrote:
> On Sun, Jan 08, 2017 at 07:17:07PM +0100, bancfc at openmailbox.org wrote:
>> On 2016-12-27 04:05, bancfc at openmailbox.org wrote:
>>> Background:
>>> Canvas fingerprinting is a technique to track users based on their
>>> GPUs. https://en.wikipedia.org/wiki/Canvas_fingerprinting
>>>
>>> Someone did some testing and the good news is the fingerprint is
>>> common for all users of the same OS across all KVM users because it
>>> presents the same virtual GPU/drivers for everybody.
>>>
>>> What I need your help to find out is whether this holds for Virgil3D
>>> users that enable graphics acceleration. (I am running on Debian and
>>> the libvirt version in the repos is too old to have this included
>>> also
>
> $ ./configure && make && make install # O:-)
>
>>> I don't have multiple machines)
>
> Oh, not even nested VMs won't hep here :(
>
>>>
>>>
>>> To test this you need:
>>>
>>> To run plain FireFox on a virtualized distro (with GL acceleration
>>> enabled in libvirt) of your choice and visit
>>> https://browserleaks.com/canvas . Then repeat the same steps with
>>> that
>>> same distro (in a VM) on another physical machine and compare values.
>>>
>>> A good result is if you see the same numbers for both machines. That
>>> means the virtual device fingerprint is uniform for all virtual
>>> users.
>>
>> Bumping. I realized I post this in holiday season when it was easily
>> missed.
>>
>
> Not only were even patches discussed during that time, but people will
> catch up on things after the break, don't worry.
>
>> Since CANVAS is about graphics drivers version the question can be
>> simplified: Is the virtio-gpu driver version uniform across KVM
>> versions?
>>
>
> I think the drivers and versions will not be the same nor different
> *all
> the time*. Based on what the method says, the main difference is done
> by font selection, hinting and antialiasing settings. I don't think
> that will be dependent on the graphics hardware. Although the hardware
> description might look the same. The details about that should
> probably
> be asked somewhere else than libvirt, e.g. whoever does virglrenderer
> or
> qemu or...
>
> I don't have another machine handy and my graphics guests are borked
> for
> some reason (and I spent a lot of time trying to fix those already), so
> I won't help much there. I tried it with some live media, but then
> realized it's not going to help. I'd have to try the same VM (not only
> distro), I guess.
>
>>
>> --
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