Microsoft Edge Chakra JavascriptFunction::ReparseAsmJsModule Parsing Issue

Microsoft Edge Chakra JavascriptFunction::ReparseAsmJsModule suffers from a parsing issue.


MD5 | e42ea1ce1dac6aa761323bae506ada67

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Microsoft Edge: Chakra: JavascriptFunction::ReparseAsmJsModule incorrectly re-parses 

CVE-2017-8755


This is similar to the <a href="/p/project-zero/issues/detail?id=1271" title="Microsoft Edge: Chakra: InterpreterStackFrame::ProcessLinkFailedAsmJsModule incorrectly re-parses" class="closed_ref" rel="nofollow"> issue 1271 </a>.

Here's the method used to re-parse asmjs modules.
void JavascriptFunction::ReparseAsmJsModule(ScriptFunction** functionRef)
{
    ParseableFunctionInfo* functionInfo = (*functionRef)->GetParseableFunctionInfo();
    Assert(functionInfo);
    functionInfo->GetFunctionBody()->AddDeferParseAttribute();
    functionInfo->GetFunctionBody()->ResetEntryPoint();
    functionInfo->GetFunctionBody()->ResetInParams();

    FunctionBody * funcBody = functionInfo->Parse(functionRef);

#if ENABLE_PROFILE_INFO
    // This is the first call to the function, ensure dynamic profile info
    funcBody->EnsureDynamicProfileInfo();
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