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  1. Qt
  2. QTBUG-74058

Invalid memory read in QJSEngine::evaluate

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    • 0dd884aca1fffcd94fbe55006c94363415aa0965 (qt/qtdeclarative/5.12)

    Description

      1. Have a release build of Qt with enabled address sanitizer.
        I configured it with:
        -developer-build -opensource -confirm-license -nomake examples -nomake tests -no-use-gold-linker -sanitize address -release
      2. Build the attached project on this build of Qt:
        #include <QCoreApplication>
        #include <QFile>
        #include <QJSEngine>
        
        int main(int argc, char *argv[])
        {
            QCoreApplication a(argc, argv);
            if (argc < 2)
                return -1;
            QFile inFile(argv[1]);
            inFile.open(QFile::ReadOnly);
            QJSEngine().evaluate(inFile.readAll());
            return 0;
        }
        
      3. Run the program passing the attached input file as parameter:
        function a(){a(a&a+a)}a()

        It will crash with output like the following:

        QML debugging is enabled. Only use this in a safe environment.
        AddressSanitizer:DEADLYSIGNAL
        =================================================================
        ==30608==ERROR: AddressSanitizer: SEGV on unknown address 0x7fc6afbd6400 (pc 0x7fc6b7f3a009 bp 0x7ffde49eea90 sp 0x7ffde49ee830 T0)
        ==30608==The signal is caused by a READ memory access.
            #0 0x7fc6b7f3a008 in QV4::Value::toNumberImpl(QV4::Value) (/home/qtrob/dev/g++-8.2.1/qt-5.12_base_declarative-asan-r/qtbase/lib/libQt5Qml.so.5+0xa0e008)
            #1 0x7fc6b7f50112 in QV4::JIT::toInt32Helper(unsigned long long) (/home/qtrob/dev/g++-8.2.1/qt-5.12_base_declarative-asan-r/qtbase/lib/libQt5Qml.so.5+0xa24112)
            #2 0x7fc6b155d16f  (/memfd:JITCode:/home/qtrob/dev/g++-8.2.1/qt-5.12_base_declarative-asan-r/qtbase/lib/libQt5Qml.so.5 (deleted)+0x16f)
        
        AddressSanitizer can not provide additional info.
        SUMMARY: AddressSanitizer: SEGV (/home/qtrob/dev/g++-8.2.1/qt-5.12_base_declarative-asan-r/qtbase/lib/libQt5Qml.so.5+0xa0e008) in QV4::Value::toNumberImpl(QV4::Value)
        ==30608==ABORTING
        

        Trying to debug this will give you this backtrace (full backtrace attached):

        1   QV4::Moth::VME::interpret(QV4::CppStackFrame *, QV4::ExecutionEngine *, const char *)                       0x7ffff66a0dee 
        2   QV4::Moth::VME::exec(QV4::CppStackFrame *, QV4::ExecutionEngine *)                                          0x7ffff66c0629 
        3   QV4::ArrowFunction::virtualCall(QV4::FunctionObject const *, QV4::Value const *, QV4::Value const *, int)   0x7ffff642577f 
        4   QV4::Runtime::method_callName(QV4::ExecutionEngine *, int, QV4::Value *, int)                               0x7ffff6931501 
        5   QV4::Moth::VME::interpret(QV4::CppStackFrame *, QV4::ExecutionEngine *, const char *)                       0x7ffff66abef8 
        6   QV4::Moth::VME::exec(QV4::CppStackFrame *, QV4::ExecutionEngine *)                                          0x7ffff66c0629 
        7   QV4::ArrowFunction::virtualCall(QV4::FunctionObject const *, QV4::Value const *, QV4::Value const *, int)   0x7ffff642577f 
        8   QV4::Runtime::method_callName(QV4::ExecutionEngine *, int, QV4::Value *, int)                               0x7ffff6931501 
        9   QV4::Moth::VME::interpret(QV4::CppStackFrame *, QV4::ExecutionEngine *, const char *)                       0x7ffff66abef8 
        10  QV4::Moth::VME::exec(QV4::CppStackFrame *, QV4::ExecutionEngine *)                                          0x7ffff66c0629 
        11  QV4::ArrowFunction::virtualCall(QV4::FunctionObject const *, QV4::Value const *, QV4::Value const *, int)   0x7ffff642577f 
        12  QV4::Runtime::method_callName(QV4::ExecutionEngine *, int, QV4::Value *, int)                               0x7ffff6931501 
        13  QV4::Moth::VME::interpret(QV4::CppStackFrame *, QV4::ExecutionEngine *, const char *)                       0x7ffff66abef8 
        14  QV4::Moth::VME::exec(QV4::CppStackFrame *, QV4::ExecutionEngine *)                                          0x7ffff66c0629 
        15  QV4::ArrowFunction::virtualCall(QV4::FunctionObject const *, QV4::Value const *, QV4::Value const *, int)   0x7ffff642577f 
        16  QV4::Runtime::method_callName(QV4::ExecutionEngine *, int, QV4::Value *, int)                               0x7ffff6931501 
        17  QV4::Moth::VME::interpret(QV4::CppStackFrame *, QV4::ExecutionEngine *, const char *)                       0x7ffff66abef8 
        18  QV4::Moth::VME::exec(QV4::CppStackFrame *, QV4::ExecutionEngine *)                                          0x7ffff66c0629 
        19  QV4::ArrowFunction::virtualCall(QV4::FunctionObject const *, QV4::Value const *, QV4::Value const *, int)   0x7ffff642577f 
        20  QV4::Runtime::method_callName(QV4::ExecutionEngine *, int, QV4::Value *, int)                               0x7ffff6931501 
        ... <Mehr>                                                                                                                     
        

      Attachments

        1. evaluate-cli.zip
          0.6 kB
        2. backtrace.txt
          200 kB
        3. QTBUG-74058.js
          0.0 kB

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              ulherman Ulf Hermann
              rlohning Robert Löhning
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