1856645 - Cookies set in normal window show up in cookies in devtools within Private Mode

Status: NEW

(DevTools :: General, defect, P2)

Description

[Kuba Orlik]

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/118.0

Steps to reproduce:

Open two windows - one regular, one in private mode. Go to mozilla.org in both of them. Open Devtools in both of them, navigate to Storage. In regular mode, run document.cookie="leaks=true". Navigate to Private Mode, open the mozilla.org tree in cookies view, see that this cookie is visible there, as well.

Actual results:

The "leaks=true" cookie is visible in the devtools in the Private Mode window

Expected results:

It should be separate, cookies set in regular windows should not leak to private windows

Comment 1

[Kuba Orlik]

Attachment: Screencast showcasing the issue

Comment 2

[Kuba Orlik]

This also happens across Firefox Containers

Comment 3

[BugBot [:suhaib / :marco/ :calixte]]

The Bugbug bot thinks this bug should belong to the 'DevTools::General' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 4

[Julian Descottes [:jdescottes]]

The exact STRs seem to be:

• open a tab in a regular Firefox window
• open the same tab in a Private Browsing Firefox window
• open the storage inspector in the Private Browsing Firefox window
• run document.cookie="leaks=true" in the regular Firefox window

You will see the cookie appear in the Storage inspector of the Private Browsing Firefox window. However the cookie is not actually set. If you close/reopen devtools, the leaks cookie is gone. And using document.cookie to read cookies will also not show this cookie.

So this is most likely only a UI bug where we incorrectly show the cookie in the UI and not an actual leak of the cookie between regular and private windows.

Comment 7

[Emma Zühlcke [:emz]]

I suspect it's an issue with how we listen for cookie changes. I see that devtool subscribes to both normal and private browsing cookie changes here: https://searchfox.org/mozilla-central/rev/3966e5534ddf922b186af4777051d579fd052bad/devtools/server/actors/resources/storage/cookies.js#528
It then calls onCookieChanged here: https://searchfox.org/mozilla-central/rev/3966e5534ddf922b186af4777051d579fd052bad/devtools/server/actors/resources/storage/cookies.js#201
but doesn't do any filtering for normal or private browsing as far as I can see? Really it should look at the cookie's OriginAttributes and compare them to the OriginAttributes of the principal of the content window the devtools instance is attached to.