mirror of
https://github.com/josdejong/mathjs.git
synced 2025-12-08 19:46:04 +00:00
35 lines
1.6 KiB
JavaScript
35 lines
1.6 KiB
JavaScript
// Expression parser security
|
|
//
|
|
// Executing arbitrary expressions like enabled by the expression parser of
|
|
// mathjs involves a risk in general. When you're using mathjs to let users
|
|
// execute arbitrary expressions, it's good to take a moment to think about
|
|
// possible security and stability implications, especially when running the
|
|
// code server side.
|
|
//
|
|
// There is a small number of functions which yield the biggest security risk
|
|
// in the expression parser of math.js:
|
|
//
|
|
// - `import` and `createUnit` which alter the built-in functionality and allow
|
|
// overriding existing functions and units.
|
|
// - `eval`, `parse`, `simplify`, and `derivative` which parse arbitrary input
|
|
// into a manipulable expression tree.
|
|
//
|
|
// To make the expression parser less vulnerable whilst still supporting most
|
|
// functionality, these functions can be disabled, as demonstrated in this
|
|
// example.
|
|
|
|
var math = require('../../index');
|
|
var limitedEval = math.eval;
|
|
|
|
math.import({
|
|
'import': function () { throw new Error('Function import is disabled') },
|
|
'createUnit': function () { throw new Error('Function createUnit is disabled') },
|
|
'eval': function () { throw new Error('Function eval is disabled') },
|
|
'parse': function () { throw new Error('Function parse is disabled') },
|
|
'simplify': function () { throw new Error('Function simplify is disabled') },
|
|
'derivative': function () { throw new Error('Function derivative is disabled') }
|
|
}, {override: true});
|
|
|
|
console.log(limitedEval('sqrt(16)')); // Ok, 4
|
|
console.log(limitedEval('parse("2+3")')); // Error: Function parse is disabled
|