Segmentation fault on Ubuntu

[gbook]

I'm writing a program using bit7z, that runs fine on Windows 11 and on Redhat 8. But when I build and run on Ubuntu 24, it segfaults. The error is occuring in a function that extracts a single file from the archive into memory. I think I'm not copying the buffer correctly... but I'm not sure why it's different between Windows, Redhat 8, and Ubuntu 24.

bool squirrel::ExtractArchiveFileToMemory(QString archivePath, QString filePath, QString &fileContents) {
    try {
        using namespace bit7z;
        std::vector<unsigned char> buffer;
        Bit7zLibrary lib(p7zipLibPath.toStdString());
        if (archivePath.endsWith(".zip", Qt::CaseInsensitive)) {
            BitFileExtractor extractor(lib, BitFormat::Zip);
            extractor.extractMatching(archivePath.toStdString(), filePath.toStdString(), buffer);
        }
        else {
            BitFileExtractor extractor(lib, BitFormat::SevenZip);
            extractor.extractMatching(archivePath.toStdString(), filePath.toStdString(), buffer);
        }
        // ----- It might be crashing here -----
        std::string str{buffer.begin(), buffer.end()};
        fileContents = QString::fromStdString(str);
        return true;
    }
    catch ( const bit7z::BitException& ex ) {
        /* Do something with ex.what()...*/
        fileContents = "Unable to extract file from archive using bit7z library [" + QString(ex.what()) + "]";
        return false;
    }
}

The segfault error within gdb

Program received signal SIGSEGV, Segmentation fault.
0x0000555555645287 in bit7z::BitInputArchive::BitInputArchive(bit7z::BitAbstractArchiveHandler const&, std::filesystem::__cxx11::path const&) ()
(gdb)

[rikyoz]

Hi!
Usually, such segmentation faults are due to a mismatch in the 7-Zip's interfaces used by bit7z and the ones provided by the 7z.so library being used.

Since 7-Zip's 23.01, the interfaces provided by the 7z.so are incompatible with the ones from the previous versions of 7-Zip or from the p7zip project.
The result is that if you build bit7z for the latest versions of 7-Zip, and then use your program with an old 7z.so, a segmentation fault will occur; and viceversa, the same result occurs if you build bit7z for older versions of 7-Zip or for p7zip, and then use a recent 7z.so.

By default, bit7z is compatible with the 7z.so from 7-Zip v23.01 and later.
You can configure bit7z differently either by specifying the correct version of 7-Zip you plan to use with your program (e.g., -DBIT7Z_7ZIP_VERSION=22.01) or by specifying whether to use the legacy interfaces or not (e.g., -DBIT7Z_USE_LEGACY_IUNKNOWN=ON or OFF).

[rikyoz]

To clarify it further, this change happened only on Linux and macOS. On Windows, 7-Zip's interfaces never changed in an incompatible way, so you can use bit7z with any version of the 7z.dll.