Bug 56063 – Inline worker powered by blob URL does not work with files URL even if allowFileAccessFromFileURLs is enabled.

• Component: WebCore JavaScript
• Status: RESOLVED FIXED

[Jian Li]

Inline worker powered by blob URL does not work with files URL even if allowFileAccessFromFileURLs is enabled.

Test script:

function runTest()
{
    var blobBuilder = new BlobBuilder();
    blobBuilder.append([
        "onmessage = function(e) {",
        "    postMessage('Hello from worker');",
        "};"
    ].join('\n'));
    var blobURL = webkitURL.createObjectURL(blobBuilder.getBlob());
    var worker = new Worker(blobURL);
    worker.onmessage = function(event) {
        alert(event.data);
     };
    worker.postMessage();
}

[Jian Li]

Created attachment 85267 [details]
Proposed Patch

[Jian Li]

Created attachment 85268 [details]
Proposed Patch

[David Levin]

I haven't looked in depth much, but this looks like a security related change to SecurityOrigin, so I bet Mr. Barth would like to at least glance at it.

[Dmitry Titov]

Interesting. I have couple of clarifying questions:

What if a shared worker is created like this, and then another page wants to connect to the same worker - should we find the worker by the blob url match? But then since blob can have more then one url which are all pointing to the same content (as a result of postMessage(blob) for example) - do all those urls match?

Also, what is the origin of the Worker as a result? what resources can it load by XHR or importScripts?

[Dmitry Titov]

Jian answered my questions offline, since Blobs inherit origin from the page that calls createObjectURL(), the origin questions are clear.

By the same token, I think we can add data: url support for Workers, by assigning the origin of the creating page to the worker created from the data: url - but this is outside of the scope of this bug.

We still need Adam to take a look :-)

[Adam Barth]

Comment on attachment 85268 [details]
Proposed Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=85268&action=review

This patch is amazing.  I love it!

> Source/WebCore/page/SecurityOrigin.cpp:83
> +    bool isBlobOrFileSystemProtocol = (m_protocol == BlobURL::blobProtocol()) || (m_protocol == "filesystem");

Will this build if ENABLE(BLOB) is false?  We might need some fancier ifdefing.

[Adam Barth]

> By the same token, I think we can add data: url support for Workers, by assigning the origin of the creating page to the worker created from the data: url - but this is outside of the scope of this bug.

Solving the data URL problem is harder because they don't carry around their origin inside of themselves.  We'll need to track the origin separately.  That's probably easier to solve for the worker case than in the general case.

[Jian Li]

Committed as https://trac.webkit.org/changeset/82311.