Arbitrary File Creation in AbstractUnArchiver

protected void extractFile( final File srcF, final File dir, final InputStream compressedInputStream, String entryName, final Date entryDate, final boolean isDirectory, final Integer mode, String symlinkDestination, final FileMapper[] fileMappers)
    throws IOException, ArchiverException
    {
        ...
        // Hmm. Symlinks re-evaluate back to the original file here. Unsure if this is a good thing...
        final File targetFileName = FileUtils.resolveFile( dir, entryName );


        // Make sure that the resolved path of the extracted file doesn't escape the destination directory
        // getCanonicalFile().toPath() is used instead of getCanonicalPath() (returns String),
        // because "/opt/directory".startsWith("/opt/dir") would return false negative.
        Path canonicalDirPath = dir.getCanonicalFile().toPath();
        Path canonicalDestPath = targetFileName.getCanonicalFile().toPath();


        if ( !canonicalDestPath.startsWith( canonicalDirPath ) )
        {
            throw new ArchiverException( "Entry is outside of the target directory (" + entryName + ")" );
        }


        try
        {
            ...
            if ( !StringUtils.isEmpty( symlinkDestination ) )
            {
                SymlinkUtils.createSymbolicLink( targetFileName, new File( symlinkDestination ) );
            }
            else if ( isDirectory )
            {
                targetFileName.mkdirs();
            }
            else
            {
                try ( OutputStream out = Files.newOutputStream( targetFileName.toPath() ) )
                {
                    IOUtil.copy( compressedInputStream, out );
                }
            }


            targetFileName.setLastModified( entryDate.getTime() );


            if ( !isIgnorePermissions() && mode != null && !isDirectory )
            {
                ArchiveEntryUtils.chmod( targetFileName, mode );
            }
        }
        catch ( final FileNotFoundException ex )
        {
            getLogger().warn( "Unable to expand to file " + targetFileName.getPath() );
        }
    }

public static File resolveFile( final File baseFile, String filename )
    {
        ...
        try
        {
            file = file.getCanonicalFile();
        }
        catch ( final IOException ioe )
        {
            // nop
        }


        return file;
    }

JNIEXPORT int
JDK_Canonicalize(const char *orig, char *out, int len)
{
    if (len < PATH_MAX) {
        errno = EINVAL;
        return -1;
    }

    if (strlen(orig) > PATH_MAX) {
        errno = ENAMETOOLONG;
        return -1;
    }

    /* First try realpath() on the entire path */
    if (realpath(orig, out)) {
        /* That worked, so return it */
        collapse(out);
        return 0;
    } else {
        /* Something's bogus in the original path, so remove names from the end
           until either some subpath works or we run out of names */
        ...

Path canonicalDirPath = dir.getCanonicalFile().toPath();
Path canonicalDestPath = targetFileName.getCanonicalFile().toPath();


if ( !canonicalDestPath.startsWith( canonicalDirPath ) )
{
    throw new ArchiverException( "Entry is outside of the target directory (" + entryName + ")" );
}

package com.example;

import java.io.File;

import org.codehaus.plexus.archiver.zip.ZipUnArchiver;

public class App 
{
    public static void main( String[] args )
    {
        ZipUnArchiver unArchiver = new ZipUnArchiver(new File("/tmp/archive.zip"));
        unArchiver.setDestDirectory(new File("/tmp/extracted_files"));
        unArchiver.extract();        
    }
}