safe-eval IS HARMFUL - so you are warned!

This package contains multiple known payloads to bypass the sandbox logic and should NOT be used for executing untrusted code. There are numerous documented sandbox escape vulnerabilities that have been reported and remain unpatched.

• Multiple sandbox escape bugs have been reported in the GitHub issues
• Prototype pollution vulnerabilities exist in the safeEval function
• Process crash vulnerabilities can be triggered by malicious code
• Context injection attacks can bypass intended restrictions

• DO NOT use this package with user-submitted data
• DO NOT use this package with code from untrusted sources
• DO NOT rely on this package for security-critical applications
• Consider alternatives like `isolated-vm`` for Node.js sandboxing

For Node.js applications, consider using:

• isolated-vm - Google's V8 Isolate API

Multiple sandbox escape vulnerabilities have been reported in the GitHub issues:

• Issue #38 - Sandbox Escape Bug
• Issue #35 - Sandbox Escape Bug
• Issue #34 - Sandbox Escape Bug
• Issue #33 - Sandbox Escape Bug
• Issue #32 - Sandbox Escape Bug
• Issue #31 - Sandbox Escape Bug
• Issue #28 - Sandbox Escape Bug
• Issue #27 - Sandbox Escape
• Issue #26 - Prototype pollution in function safeEval

Before using this module, ask yourself if there are no better options than using safe-eval. It is potentially better than the bad old eval() but has harmful potential.

NOTE

safe-eval 0.3.0 and below are affected by a sandbox breakout vulnerability - NSP 337, CVE-2017-16088.

Version 0.4.0 fixes this vulnerability. It is highly recommended to upgrade to the latest version if you are using safe-eval for executing code not generated by yourself. Thanks @kauegimenes for the patch.

UPDATE 27/08/2018: There are still ways to crash the Node process, please use safe-eval only with content created by yourself or from trusted sources. User-submitted data should not be run through safe-eval. Thanks @cpcallen for the report.

safe-eval lets you execute JavaScript code without having to use the much discouraged and feared upon eval(). safe-eval has access to all the standard APIs of the V8 JavaScript Engine. By default, it does not have access to the Node.js API, but can be given access using a context object. It is implemented using node's vm module.

Currently, it works only with Node.js, and the JavaScript code must be an expression (something which evaluates to a value).

npm install safe-eval --save

var safeEval = require('safe-eval')

safeEval(code, [context], [options])

code is the JavaScript code you want to execute.

context is an object of methods and properties, these methods and properties are interpreted as global objects in code. Be careful about the objects you are passing to the context API, because they can completely defeat the purpose of safe-eval.

options is the options object for the vm executing the code.

// string concatenation var code = '"app" + "le"' var evaluated = safeEval(code) // "apple"

// math var code = 'Math.floor(22/7)' var evaluated = safeEval(code) // 3.142857142857143

// JSON var code = '{name: "Borat", hobbies: ["disco dance", "sunbathing"]}' var evaluated = safeEval(code) // {name: "Borat", hobbies: ["disco dance", "sunbathing"]}

// function expression var code = '(function square(b) { return b * b; })(5)' var evaluated = safeEval(code) // 25

// no access to Node.js objects var code = 'process' safeEval(code) // THROWS!

// your own context API - access to Node's process object and a custom function var code = '{pid: process.pid, apple: a()}' var context = { process: process, a: function () { return 'APPLE' } } var evaluated = safeEval(code, context) // { pid: 16987, apple: 'APPLE' }

// pass an options object to the vm var code = 'process' safeEval(code, {}, { filename: 'myfile.js'}) // myfile.js can be seen in the stacktrace

Copyright (c) 2016 Hage Yaapa

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

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