Always validate and sanitize file paths from user input to prevent directory traversal attacks. Malicious actors can use path manipulation techniques like `../../../` sequences or absolute paths to access files outside intended directories, potentially overwriting critical system files or accessing sensitive data.
Always validate and sanitize file paths from user input to prevent directory traversal attacks. Malicious actors can use path manipulation techniques like ../../../ sequences or absolute paths to access files outside intended directories, potentially overwriting critical system files or accessing sensitive data.
Key validation steps:
Example of vulnerable code:
# BAD: No validation allows path traversal
model_name = user_input # Could be "../../../../passwd"
file_path = os.path.join(models_dir, model_sub_directory, model_name)
Example of secure implementation:
# GOOD: Validate filename and check final path
def validate_filename(filename):
# Reject dangerous characters and sequences
if '..' in filename or '/' in filename or '\\' in filename:
return False
return True
if not validate_filename(model_name):
raise ValueError("Invalid filename")
file_path = os.path.join(models_dir, model_sub_directory, model_name)
resolved_path = os.path.abspath(file_path)
# Ensure final path is within allowed directory
if not resolved_path.startswith(os.path.abspath(models_dir)):
raise ValueError("Path outside allowed directory")
This prevents attackers from writing malicious code to locations like custom_nodes/*/.__init__.py or accessing sensitive system directories.
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