keystone-bdc/lib/security/csrf.js at master · correasebastian/keystone-bdc · GitHub

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var crypto = require('crypto');
var scmp = require('scmp');
var utils = require('keystone-utils');

exports.TOKEN_KEY = '_csrf';
exports.LOCAL_KEY = 'csrf_token_key';
exports.LOCAL_VALUE = 'csrf_token_value';
exports.SECRET_KEY = exports.TOKEN_KEY + '_secret';
exports.SECRET_LENGTH = 10;
exports.CSRF_HEADER_KEY = 'x-csrf-token';
exports.XSRF_HEADER_KEY = 'x-xsrf-token';
exports.XSRF_COOKIE_KEY = 'XSRF-TOKEN';

function tokenize(salt, secret) {
	return salt + crypto.createHash('sha1').update(salt + secret).digest('base64');
}

exports.createSecret = function() {
	return crypto.pseudoRandomBytes(exports.SECRET_LENGTH).toString('base64');
};

exports.getSecret = function(req) {
	return req.session[exports.SECRET_KEY] || (req.session[exports.SECRET_KEY] = exports.createSecret());
};

exports.createToken = function(req) {
	return tokenize(utils.randomString(exports.SECRET_LENGTH), exports.getSecret(req));
};

exports.getToken = function(req, res) {
	res.locals[exports.LOCAL_VALUE] = res.locals[exports.LOCAL_VALUE] || exports.createToken(req);
	res.cookie(exports.XSRF_COOKIE_KEY, res.locals[exports.LOCAL_VALUE]);
	return res.locals[exports.LOCAL_VALUE];
};

exports.requestToken = function(req) {
	if (req.body && req.body[exports.TOKEN_KEY]) {
		return req.body[exports.TOKEN_KEY];
	} else if (req.query && req.query[exports.TOKEN_KEY]) {
		return req.query[exports.TOKEN_KEY];
	} else if (req.headers && req.headers[exports.XSRF_HEADER_KEY]) {
		return req.headers[exports.XSRF_HEADER_KEY];
	} else if (req.headers && req.headers[exports.CSRF_HEADER_KEY]) {
		return req.headers[exports.CSRF_HEADER_KEY];
	}
	return '';
};

exports.validate = function(req, token) {
	if (arguments.length === 1) {
		token = exports.requestToken(req);
	}
	if (typeof token !== 'string') {
		return false;
	}
	return scmp(token, tokenize(token.slice(0, exports.SECRET_LENGTH), req.session[exports.SECRET_KEY]));
};

exports.middleware = {

	init: function(req, res, next) {
		res.locals[exports.LOCAL_KEY] = exports.LOCAL_VALUE;
		exports.getToken(req, res);
		next();
	},

	validate: function(req, res, next) {

		// Bail on safe methods
		if (req.method === 'GET' || req.method === 'HEAD' || req.method === 'OPTIONS') {
			return next();
		}

		// Validate token
		if (exports.validate(req)) {
			next();
		} else {
			res.statusCode = 403;
			next(new Error('CSRF token mismatch'));
		}

	}

};