1938618 - Make navigator.clipboard.read() do all DLP requests at once

Status: NEW

(Firefox :: Data Loss Prevention, defect)

Description

[Greg Stoll :gstoll]

Unlike the clipboard event case, navigator.clipboard.read() does separate requests for each flavor of the clipboard, meaning that we can't use the same user_action_id for them.

To fix this we'd need to make ClipboardDataSnapshot::GetData() analyze the full contents of the clipboard, like we do in ClipboardContentAnalysisParent::RecvGetAllClipboardDataSync().

I don't think this is a blocker for 1.0 because if we only analyze one format on the clipboard this doesn't matter.

See comments in browser_clipboard_read_async_content_analysis.js for how to fix up the test after doing this.

Comment 1

[Greg Stoll :gstoll]

I take back that "if we only analyze one format on the clipboard this doesn't matter" - this call explicitly gets all of the clipboard contents, and if it's being done in this way it's inconvenient to only send one of those formats. So fixing this would let us easily only analyze one format. Sigh.

I'll make it a blocker for now.

Comment 2

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

The severity field is not set for this bug.
:handyman, could you have a look please?

For more information, please visit BugBot documentation.

Comment 3

[Greg Stoll :gstoll]

OK, a few things:

If we implement bug 1938188 and only analyze the text contents of the clipboard, I think this would not be so bad. We'd just do one DLP request (with a corresponding dialog) each time the JS code reads the text contents, which I'm guessing would only be one time for most cases.

However, I think this wouldn't be too hard to fix. In nsClipboardProxy::GetDataSnapshotSync() we already call contentAnalysis->SendGetAllClipboardDataSync() and wrap the result in a nsBaseClipboard::ClipboardPopulatedDataSnapshot. I think if we do a similar thing in nsClipboardProxy::GetDataSnapshot() that would fix this issue, and it would just require adding a GetAllClipboardData (non-sync) message to PClipboardContentAnalysis.

Comment 4

[Greg Stoll :gstoll]

Attachment: Bug 1938618 - make Content Analysis cache result for navigator.clipboard.read() calls r=#dlp-reviewers!

Comment 5

[Greg Stoll :gstoll]

This is more complicated than I had anticipated, and I don't think the consequences are very bad, so I'm making this not a 1.0 blocker and setting it aside for now.

After chatting with :edgar, we'd like to make a new method, something like Result<nsCOMPtr<nsISupports>, nsresult> GetNativeClipboardData(ClipboardType aWhichClipboard, const nsACString& aFlavor); that would return the full clipboard contents, and make navigator.clipboard.read() use that. That would make this bug significantly easier to implement.