unpack_unitypackages.py

import os
import gzip
import shutil
import tarfile

def ensure_dir(dir):
    if not os.path.exists(dir):
        os.makedirs(dir)

def move_if_exists(src, dst):
    if os.path.exists(src):
        ensure_dir(os.path.dirname(dst))
        shutil.move(src, dst)

def read_all_text(path):
    with open(path, 'r') as f:
        return f.read()

def unpack_unitypackage(path):
    package_name = os.path.basename(path)
    package_dir = os.path.dirname(path)

    unpack_folder = os.path.join(package_dir, os.path.splitext(package_name)[0])
    tar_path = os.path.join(unpack_folder, "archtemp.tar")

    # Create target folder for package files
    ensure_dir(unpack_folder)

    # Extract unitypackage (gzip)
    with gzip.open(path, 'rb') as f_in:
        with open(tar_path, 'wb+') as f_out:
            shutil.copyfileobj(f_in, f_out)
    
    # Create folder to extract artifacts to
    artifact_folder = os.path.join(unpack_folder, "artifacts")
    ensure_dir(artifact_folder)

    # Extract artifacts (tar)
    tar = tarfile.open(tar_path, "r:*")
    tar.extractall(artifact_folder)
    tar.close()

    # delete the archive
    os.remove(tar_path)

    # Get all subdirectories of the archive folder
    artifact_dirs = get_subdirs(artifact_folder)

    # Malicious folder in case someone has messed with the package and wants to extract to a different directory
    malicious_folder = os.path.join(unpack_folder, "Malicious")

    # Move all files and subdirectories to the target directory
    for artifact_name in artifact_dirs:
        artifact_dir = os.path.join(artifact_folder, artifact_name)

        final_path = read_all_text(os.path.join(artifact_dir, "pathname"))
        
        final_name = os.path.basename(final_path)
        
        # If pathname contains a ".." in the path, it is not a valid path, extract it to a "Malicious" folder
        if ".." in final_path or final_path.startswith("/"):
            final_path = os.path.join(malicious_folder, artifact_name, final_name)
        else:
            final_path = os.path.join(unpack_folder, final_path)
        
        move_if_exists(os.path.join(artifact_dir, "asset"), final_path)
        move_if_exists(os.path.join(artifact_dir, "asset.meta"), final_path + ".meta")
    
    # Delete the artifact folder
    shutil.rmtree(artifact_folder)


# Get all subdirecotries of a directory
def get_subdirs(dir):
    return [name for name in os.listdir(dir)
            if os.path.isdir(os.path.join(dir, name))]

# Unpack all .unitypackage files
def unpack_all(sourceDir):
    # Get all .unitypackage files in the source directory
    packages = [name for name in os.listdir(sourceDir) if name.endswith(".unitypackage")]

    # Unpack with 7zip
    for package in packages:
        unpack_unitypackage(os.path.join(sourceDir, package))

# Main function
if __name__ == "__main__":
    unpack_all(".")
    print("Unpacking complete!")