🏜️ @exact-realty/lot 🏖️

Welcome to @exact-realty/lot — the versatile ECMAScript sandbox you've been looking for!

Our sandbox supports multiple runtimes and allows for bidirectional communication, ensuring you have the flexibility and security to run your code in various environments.

🚀 Features

• Support for multiple runtimes:
  • Browser (using an iframe with a worker inside or just an iframe)
  • Dedicated worker (can run in the browser or with Deno)
  • Node.js
• Browser isolation using Content Security Policy (CSP)
• Message passing using the MessageEvent class and event listeners for secure communication using the structured clone algorithm
• Hardening of global variables, including Function and eval, to prevent direct code execution
• Bidirectional communication, enabling the parent to call into the sandbox and vice versa

💻 Installation

To install, run:

npm install "@exact-realty/lot"

yarn add "@exact-realty/lot"

📚 Usage

Using our sandbox is easy! First, import the desired sandbox function, then call it with your code and any additional parameters. Here's an example using browserSandbox:

import { browserSandbox } from '@exact-realty/lot';

const sandbox = await browserSandbox(`
  /* sandboxed code*/;
  module.exports={hello:(name)=>\`Hello, ${name}!\`}; 
`);
const result = await sandbox('hello', 'World');
console.log(result); // Output: "Hello, World!"

Our sandbox provides two interfaces:

export interface IPerformTask {
  (op: string, ...args: unknown[]): Promise<unknown>;
}

export interface ISandbox {
  (
    script: string,
    allowedGlobals?: string[] | undefined | null,
    externalMethods?: Record<string, unknown> | null,
    abort?: AbortSignal,
    options?: TSandboxOptions,
  ): Promise<IPerformTask>;
}

export type TSandboxOptions = {
	browserRequireWorker?: boolean;
	workerType?: WorkerOptions['type'];
}

ISandbox is an interface for the browserSandbox, nodejsSandbox and workerSandbox functions. It takes a string script representing the code to be sandboxed, an optional array of allowed global variables allowedGlobals, an optional object of external methods externalMethods, and an optional AbortSignal abort. It returns a promise that resolves to an implementation of IPerformTask.

IPerformTask is an interface for the result of the various sandbox function. It takes a string op representing the function name and a list of arguments, and it returns a promise that resolves to the result of the task.

The script to be sandboxed, script, must expose an object in module.exports with a dictionary of the different functions that can be called from outside. The type of module.exports is Record<string, typeof Function.prototype>.

🤝 Contributing

We welcome any contributions and feedback! Please feel free to submit pull requests, bug reports or feature requests to our GitHub repository.

❗️ Disclaimer

⚠️ Please note that even though we have implemented several security measures, it's important to understand that sandbox escapes are always a possibility. Running untrusted code in Node.js is especially risky due to its inherent platform limitations. Our sandbox relies on node:vm, which was not designed for running untrusted code.

To mitigate these risks, we strongly recommend taking a security-in-depth approach and relying on additional security mechanisms such as process isolation, seccomp(2), pledge(2), ProcessSystemCallDisablePolicy and SELinux, to name a few. Where feasible, we also recommend static code analysis and code reviews, as well as adequate auditing and logging.

Note that the sandbox does not prevent denial-of-service attacks such as infinite loops or memory exhaustion. It's important to take appropriate measures to prevent these types of attacks, such as setting resource limits or using timeouts.

📜 License

This project is released under the ISC license. Check out the LICENSE file for more information.