Disallow unsanitized code (no-unsanitized)

These rules disallow unsafe coding practices that may result into security vulnerabilities. We will disallow assignments (e.g., to innerHTML) as well as calls (e.g., to insertAdjacentHTML) without the use of a pre-defined escaping function. The escaping functions must be called with a template string. The function names are hardcoded as Sanitizer.escapeHTML and escapeHTML. The plugin also supports the Sanitizer API and calls to .setHTML() are also allowed by default.

This plugin is built for and used within Mozilla to maintain and improve the security of our products and services.

Rule Details

method

The method rule disallows certain function calls. E.g., document.write() or insertAdjacentHTML(). See docs/rules/method.md for more.

property

The property rule disallows certain assignment expressions, e.g., to innerHTML.

See docs/rules/property.md for more.

Examples

Here are a few examples of code that we do not want to allow:

1foo.innerHTML = input.value;
2bar.innerHTML = "<a href='" + url + "'>About</a>";

A few examples of allowed practices:

1foo.innerHTML = 5;
2bar.innerHTML = "<a href='/about.html'>About</a>";
3bar.innerHTML = escapeHTML`<a href='${url}'>About</a>`;

Install

With yarn or npm:

1$ yarn add -D eslint-plugin-no-unsanitized
2$ npm install --save-dev eslint-plugin-no-unsanitized

Usage

Flat config

1import nounsanitized from "eslint-plugin-no-unsanitized";
2
3export default config = [nounsanitized.configs.recommended];

or

1import nounsanitized from "eslint-plugin-no-unsanitized";
2
3export default config = [
4    {
5        files: ["**/*.js"],
6        plugins: { nounsanitized },
7        rules: {
8            "no-unsanitized/method": "error",
9            "no-unsanitized/property": "error",
10        },
11    },
12];

eslintrc

In your .eslintrc.json file enable this rule with the following:

1{
2    "extends": ["plugin:no-unsanitized/recommended-legacy"]
3}

Or:

1{
2    "plugins": ["no-unsanitized"],
3    "rules": {
4        "no-unsanitized/method": "error",
5        "no-unsanitized/property": "error"
6    }
7}

Documentation

See docs/.