safe-eval)

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.

What is this?

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).

Installation

sh

npm install safe-eval-2 --save





Usage

js

var safeEval = require('safe-eval-2')





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.



$3

js

// string concatenation

var code = '"app" + "le"'

var evaluated = safeEval(code) // "apple"

js

// math

var code = 'Math.floor(22/7)'

var evaluated = safeEval(code) // 3.142857142857143

js

// JSON

var code = '{name: "Borat", hobbies: ["disco dance", "sunbathing"]}'

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

js

// function expression

var code = '(function square(b) { return b * b; })(5)'

var evaluated = safeEval(code) // 25

js

// no access to Node.js objects

var code = 'process'

safeEval(code) // THROWS!

js

// 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' }

js

// pass an options object to the vm

var code = 'process'

safeEval(code, {}, { filename: 'myfile.js'}) // myfile.js can be seen in the stacktrace

License (MIT)

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.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

safe-eval ![npm version](https://badge.fury.io/js/safe-eval) ![Build Status](https://travis-ci.org/hacksparrow/safe-eval)

What is this?

Installation

sh

npm install safe-eval-2 --save





Usage

js

var safeEval = require('safe-eval-2')





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

code

 is the JavaScript code you want to execute.

options

 is the options object for the vm executing the code.



$3

js

// string concatenation

var code = '"app" + "le"'

var evaluated = safeEval(code) // "apple"

js

// math

var code = 'Math.floor(22/7)'

var evaluated = safeEval(code) // 3.142857142857143

js

// JSON

var code = '{name: "Borat", hobbies: ["disco dance", "sunbathing"]}'

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

js

// function expression

var code = '(function square(b) { return b * b; })(5)'

var evaluated = safeEval(code) // 25

js

// no access to Node.js objects

var code = 'process'

safeEval(code) // THROWS!

js

// 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' }

js

// pass an options object to the vm

var code = 'process'

safeEval(code, {}, { filename: 'myfile.js'}) // myfile.js can be seen in the stacktrace