Open Bug 1670942 Opened 6 months ago Updated 5 months ago

privacy.firstparty.isolate makes PDF elements and text blurry

Categories

(Firefox :: PDF Viewer, defect)

Firefox 83
defect

Tracking

()

UNCONFIRMED
Tracking Status
firefox83 --- wontfix
firefox84 --- affected

People

(Reporter: tauin, Unassigned)

References

(Blocks 1 open bug)

Details

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Firefox/78.0

Steps to reproduce:

  1. set privacy.firstparty.isolate to true
  2. Open Online PDF

Actual results:

The PDF's elements (Notably text) become blurry and pixilated, still readable but inaccurate.

Expected results:

PDF text and elemet should appear as sharp as when privacy.firstparty.isolate is off

Component: Untriaged → PDF Viewer
Summary: privacy.firstparty.isolate makes PDF elements blurry → privacy.firstparty.isolate makes PDF elements and text blurry

I just tried with a pdf file I've and I don't see any difference.
Could you attach a pdf file or give us an url to reproduce ?

Update, this only works on online PDF's and not PDF's stored on the users computer locally.

That's quite odd. We have seen this issue with the Resist Fingerprinting pref but I'm not sure why it would be happening with FPI. I can reproduce though!

I found this comment on github:
https://github.com/mozilla/pdf.js/issues/10509#issuecomment-554753081
maybe it could be related.

ive done some testing, so

Having privacy.firstparty.isolate on with privacy.resistFingerprinting off does nothing, PDF renders normally
Having privacy.firstparty.isolate off with privacy.resistFingerprinting on brakes dark mode (seems to ignore it) but the PDF renders fine
Having both on breaks theming and the PDF render.
Im not sure how the two interact to make this bug, considering that neither one breaks the PDF itself independently

(In reply to tauin from comment #6)

ive done some testing, so

Having privacy.firstparty.isolate on with privacy.resistFingerprinting off does nothing, PDF renders normally
Having privacy.firstparty.isolate off with privacy.resistFingerprinting on brakes dark mode (seems to ignore it) but the PDF renders fine
Having both on breaks theming and the PDF render.
Im not sure how the two interact to make this bug, considering that neither one breaks the PDF itself independently

I bet the code here broke and we need to update it due to Principal changes. Unfortunately I lack a machine I can debug on due to the move, but if no one else can investigate sooner I will get to it in the next couple weeks I hope. We're won't be able to ship this until the next cycle anyway.

Bug 1495204? Which might also explain the latest comments in Bug 1537955 that the issue still happens?

however ... https://bugzilla.mozilla.org/show_bug.cgi?id=1495204#c2 - I can no longer reproduce the issue in bug 1495204, using Nightly 83 and tom's pdf

It only occurs for me on Ubuntu 20.04 with 1.25 scaling factor and larger (Nightly 83 with FPI and RFP enabled). It's not a regression and can be reproduced going back to 2017 with 1.5 scaling factor.

(In reply to Simon Mainey from comment #8)

Bug 1495204? Which might also explain the latest comments in Bug 1537955 that the issue still happens?

however ... https://bugzilla.mozilla.org/show_bug.cgi?id=1495204#c2 - I can no longer reproduce the issue in bug 1495204, using Nightly 83 and tom's pdf

Im not sure its related to bug 1495204, I do get errors though

SecurityError: Permission denied to access property "windowGlobalChild" on cross-origin object ExtensionUtils.jsm:114
getInnerWindowID resource://gre/modules/ExtensionUtils.jsm:114
get resource://gre/modules/ExtensionCommon.jsm:402
get resource://gre/modules/ExtensionCommon.jsm:537
close resource://gre/modules/ExtensionContent.jsm:931
destroyed resource://gre/modules/ExtensionContent.jsm:1005
observe resource://gre/modules/ExtensionContent.jsm:1023

SecurityError: Permission denied to access property "removeEventListener" on cross-origin object

[Exception... "Favicon at "https://dlcdnets.asus.com/favicon.ico" failed to load: Not Found." nsresult: "0x80004005 (NS_ERROR_FAILURE)" location: "JS frame :: resource:///modules/FaviconLoader.jsm :: onStopRequest :: line 241" data: no]

(In reply to tauin from comment #10)

Im not sure its related to bug 1495204, I do get errors though

to clarify: bug 1495203 is about the getting system principal errors: for me it's reproducible until nightly 83

Severity: -- → S3
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