Fingerprinting Protections v2: Workers

[pes10k]

This is a sub-issue of the larger fingerprint defense reorganization issue: #8787

Currently farbling protections are not applied in workers. Brave should apply farbling protections in workers.

[abrahamjuliot]

@pilgrim-brave
@pes10k
Hardware concurrency appears consistent in workers now. Per #9186, should this fix include [all] offscreen canvas rendering contexts? Webgl vendor and renderer are still exposed via workers. I presume shaders precisions and max constants are also exposed.

[pes10k]

@abrahamjuliot thank you for the comment / catch. This is suprising, and is being into looked into now. Thanks for the help!

[LaurenWags]

@pes10k @pilgrim-brave could you guys help out with the test plan for this one?

I thought maybe it would be to go to the QA pages @pes10k set up and confirm the "Worker" column but on a clean profile with below build not everything is acting as expected. Is this because the test plan should be different? or is there an issue here?

Brave	1.16.52 Chromium: 86.0.4240.68 (Official Build) dev (x86_64)
Revision	ad72ee9aa8e15ed300df1238e76c7a8f4d686f97-refs/branch-heads/4240@{#1097}
OS	macOS Version 10.14.6 (Build 18G3020)

labeling as QA/Blocked until this is sorted.

[pes10k]

I'm not seeing this on nightly currently (see below screenshot) so maybe this is just something that needs to be uplifted? (cc @pilgrim-brave )

[LaurenWags]

@pes10k what is your shield setting here? also it might be worth looking at both pages. I'm definitely seeing some inconsistencies/unexpected results. Please see below screenshots/notes. Once you get to review to confirm that the error is with FP code and not the testing page, I'm happy to log any follow up issues needed.

1.16.x

Standard shield setting for FP

For both pages, the Worker column for WebGL Drawing has a different value than the other columns. Since this WebGL Drawing is only in standard (per the Mode column), I expected the Worker value to match the other column values.

For both pages, the Worker column for Canvas has a different value than the other columns. Since Canvas is available in both standard and strict (per the Mode column), I expected the Worker value to match the other column values. **Additionally, note that the Worker value from the top page matches the This Page, Local Frame and Remote Frame values for the lower page. Seems odd, no?

Strict shield setting for FP

For both pages, the Worker column for WebGL Drawing matches the other columns and is different between the two pages. Since this WebGL Drawing is only in standard (per the Mode column), I expected the values to be the same as when shields = standard. Am I misunderstanding this?

1.17.x

Standard shield setting for FP

For both pages, the Worker column for WebGL Drawing has a different value than the other columns. Since this WebGL Drawing is only in standard (per the Mode column), I expected the Worker value to match the other column values.

For top page (dev-pages.bravesoftware.com/farbling.html), the Worker column for Canvas has a different value than the other columns.
For the bottom page, (dev-pages.brave.software/farbling.html), the Worker column for Canvas is the same across all columns. Not sure why he two pages are acting differently?

Strict shield setting for FP

For both pages, the Worker column for WebGL Drawing matches the other columns and is different between the two pages. Since this WebGL Drawing is only in standard (per the Mode column), I expected the values to be the same as when shields = standard. Am I misunderstanding this?

For top page (dev-pages.bravesoftware.com/farbling.html), the Worker column for Canvas has a different value than the other columns.
For the bottom page, (dev-pages.brave.software/farbling.html), the Worker column for Canvas is the same across all columns. Not sure why he two pages are acting differently?

Note - shield settings aren't pictured because they cover the table, however, if you look at WebGL Vendor and Render and User Agent you can see that they are behaving as expected for std/strict so I am positive that the shield settings are accurate, I just don't know why these two aren't working as expected.

[pes10k]

Hmm, my shield settings are all default, and im on 1.17.17 Chromium: 86.0.4240.72 (Official Build) nightly (x86_64). I dont have a good explanation for this. I believe @pilgrim-brave is working on an issue related to this, but would be best if he can confirm.

[LaurenWags]

@pes10k @rebron logged some follow up issues here since it seems like there's still some work to be done in this area. They are:

• Fingerprinting Protections v2: Workers - WebGL Drawing - follow up to 11368, 11839 #12098
• Fingerprinting Protections v2: Workers - Canvas - follow up to 11368 #12099

Going to mark this issue as QA/No and release-notes/exclude since it's not fully completed and testing should be done with the above logged issues. Please let me know if there are any objections to this.