1762952 - structuredClone should not clone SharedArrayBuffer if not cross-origin isolated

Status: RESOLVED FIXED

(Core :: DOM: postMessage, defect, P3)

Description

[valentinium]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/102.0.4959.0 Safari/537.36

Steps to reproduce:

let { SharedArrayBuffer=sayTheLineBart() } = globalThis;

console.assert(crossOriginIsolated === false, "Specific to non-isolated");

try {
structuredClone(new SharedArrayBuffer(1));
console.assert(false, "Shouldn’t clone SAB at all without cross-origin isolation.");
} catch (err) {
console.assert(err.code === DOMException.DATA_CLONE_ERR, "Should throw DataCloneError");
}

function sayTheLineBart() {
return new WebAssembly.Memory({
initial: 0,
maximum: 0,
shared: 1
}).buffer.constructor;
}

Actual results:

SharedArrayBuffer is cloned successfully in a non cross-origin isolated env.

Expected results:

DataCloneError should be thrown.

Verified that the current behavior specified by HTML is by design (https://github.com/whatwg/html/issues/7781) because the Firefox behavior is arguably just trying to be “smarter” (i.e., since it’s known to be safe here). Consistency would still be best.

Comment 1

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

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

Comment 2

[Olli Pettay [:smaug][[e-mail]]]

Tom, want to take a look? This should be just some missing flag or such.

Comment 3

[Olli Pettay [:smaug][[e-mail]]]

(I believe Eden will be on leave for awhile.)

Comment 4

[Tom S [:evilpie]]

Attachment: Bug 1762952 - structuredClone should not always allow cloning SharedArrayBuffers. r?smaug

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/mozilla-central/rev/28ecef349562
structuredClone should not always allow cloning SharedArrayBuffers. r=smaug

Comment 6

[Norisz Fay [:noriszfay]]

https://hg.mozilla.org/mozilla-central/rev/28ecef349562