Patched code sample

import importlib
import sys
import os

# The vulnerability CVE-2024-27304 (likely a typo in the user's request) was caused
# by using `dill.loads()` to deserialize a user-provided logit processor,
# which allows for arbitrary code execution.
#
# The fix is to stop using deserialization altogether and instead load the
# processor by its module and class name, which is a safe, standard Python
# practice. This ensures that only code already present on the system can be
# imported and executed.

def load_logit_processor_safely(processor_path: str):
    """
    Safely loads a logit processor class from a specified module path
    instead of deserializing an untrusted object.

    Args:
        processor_path: A string in the format "module.submodule:ClassName".
    """
    try:
        if ":" not in processor_path:
            raise ValueError(
                "Invalid processor path format. Expected 'module:ClassName'."
            )
        
        module_path, class_name = processor_path.split(":")
        
        # Safely import the specified module.
        # This only loads code from the Python path, not arbitrary data.
        module = importlib.import_module(module_path)
        
        # Get the class from the loaded module.
        processor_class = getattr(module, class_name)
        
        # Instantiate the class.
        processor_instance = processor_class()
        
        print(f"Successfully and safely loaded processor: {class_name}")
        return processor_instance

    except (ImportError, AttributeError, ValueError) as e:
        print(f"Error loading processor: {e}", file=sys.stderr)
        return None

# --- Example Usage ---
# To demonstrate, we simulate a custom processor file that would exist on the server.
if __name__ == "__main__":
    
    # Create a dummy processor file for the demonstration.
    # In a real scenario, this file would already be part of the codebase.
    processor_code = """
class MyCustomLogitProcessor:
    def __init__(self):
        print("MyCustomLogitProcessor instance created.")
    
    def process(self, logits):
        print("Processing logits...")
        return logits

class AnotherProcessor:
     def __init__(self):
        print("AnotherProcessor instance created.")
"""
    
    # Create a dummy module file
    with open("my_processors.py", "w") as f:
        f.write(processor_code)

    print("--- Attempting to load a valid, known processor ---")
    # This is the safe way to specify a processor to load.
    # The server loads code it already has, preventing RCE.
    safe_path = "my_processors:MyCustomLogitProcessor"
    processor = load_logit_processor_safely(safe_path)
    
    if processor:
        processor.process(logits=[0.1, 0.9])

    print("\n--- Attempting to load a non-existent processor ---")
    invalid_path = "my_processors:NonExistentProcessor"
    load_logit_processor_safely(invalid_path)

    print("\n--- Attempting to load from a non-existent module ---")
    invalid_module_path = "non_existent_module:MyProcessor"
    load_logit_processor_safely(invalid_module_path)

    # Clean up the dummy file.
    os.remove("my_processors.py")