I don't know where to apply the Content Security Policy (CSP) snippet below in my code;
Content-Security-Policy: script-src 'self' https://apis.google.com
Should it be in the HTML?
Will it be best implemented in JavaScript as in the code snippet below?
var policy = "default-src 'self'";
http.createServer(function (req, res) {
res.writeHead(200, {
'Content-Security-Policy': policy
});
});
You just need to set it in the HTTP Header, not the HTML. This is a working example with express 4 with a static server:
var express = require('express');
var app = express();
app.use(function(req, res, next) {
res.setHeader("Content-Security-Policy", "script-src 'self' https://apis.google.com");
return next();
});
app.use(express.static(__dirname + '/'));
app.listen(process.env.PORT || 3000);
If you want more information about CSP, this is an excelent article: http://www.html5rocks.com/en/tutorials/security/content-security-policy/
Hope that helps!
For a node.js application without using any external framework e.g. express:
const http = require('http');
http.createServer((request, response) => {
request.on('error', (err) => {
console.error(err);
// for this simple example I am not including the data event
// e.g. if the request contains data in the body
}).on('end', () => {
response.on('error', (err) => {
console.error(err);
});
// you can set your headers with setHeader or
// use writeHead as a "shortcut" to include the statusCode.
// Note writeHead won't cache results internally
// and if used in conjuction with setHeader will take some sort of "precedence"
response.writeHead(200, {
"Content-Security-Policy": "default-src 'self'"
// other security headers here...
});
response.end("<html><body><h1>Hello, Security Headers!</h1></body></html>");
});
}).listen(8080);
See the node.js documentation for more details on setting headers on the response object
If you are using Express, I suggest taking a look at helmet. In addition to increased options & flexibility (handling CSP violations, nonces...etc), there are a lot of inconsistencies in how browsers implement CSP. Helmet looks at the user-agent of the browser and sets the appropriate header and value for that browser. If no user-agent is matched, it will set all the headers with the 2.0 spec.
// Make sure you run "npm install helmet-csp" to get the csp package.
const csp = require('helmet-csp')
app.use(csp({
directives: {
defaultSrc: ["'self'"],
styleSrc: ["'self'", 'maxcdn.bootstrapcdn.com']
}
}))
