server/lib/public/AppFramework/Http/ContentSecurityPolicy.php
Lukas Reschke 9e6634814e
Add support for CSP nonces
CSP nonces are a feature available with CSP v2. Basically instead of saying "JS resources from the same domain are ok to be served" we now say "Ressources from everywhere are allowed as long as they add a `nonce` attribute to the script tag with the right nonce.

At the moment the nonce is basically just a `<?php p(base64_encode($_['requesttoken'])) ?>`, we have to decode the requesttoken since `:` is not an allowed value in the nonce. So if somebody does on their own include JS files (instead of using the `addScript` public API, they now must also include that attribute.)

IE does currently not implement CSP v2, thus there is a whitelist included that delivers the new CSP v2 policy to newer browsers. Check http://caniuse.com/#feat=contentsecuritypolicy2 for the current browser support list. An alternative approach would be to just add `'unsafe-inline'` as well as `'unsafe-inline'` is ignored by CSPv2 when a nonce is set. But this would make this security feature unusable at all in IE. Not worth it at the moment IMO.

Implementing this offers the following advantages:

1. **Security:** As we host resources from the same domain by design we don't have to worry about 'self' anymore being in the whitelist
2. **Performance:** We can move oc.js again to inline JS. This makes the loading way quicker as we don't have to load on every load of a new web page a blocking dynamically non-cached JavaScript file.

If you want to toy with CSP see also https://csp-evaluator.withgoogle.com/

Signed-off-by: Lukas Reschke <lukas@statuscode.ch>
2016-10-24 12:27:50 +02:00

87 lines
2.9 KiB
PHP

<?php
/**
* @copyright Copyright (c) 2016, ownCloud, Inc.
*
* @author Lukas Reschke <lukas@statuscode.ch>
* @author Morris Jobke <hey@morrisjobke.de>
* @author sualko <klaus@jsxc.org>
*
* @license AGPL-3.0
*
* This code is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License, version 3,
* along with this program. If not, see <http://www.gnu.org/licenses/>
*
*/
namespace OCP\AppFramework\Http;
/**
* Class ContentSecurityPolicy is a simple helper which allows applications to
* modify the Content-Security-Policy sent by ownCloud. Per default only JavaScript,
* stylesheets, images, fonts, media and connections from the same domain
* ('self') are allowed.
*
* Even if a value gets modified above defaults will still get appended. Please
* notice that ownCloud ships already with sensible defaults and those policies
* should require no modification at all for most use-cases.
*
* @package OCP\AppFramework\Http
* @since 8.1.0
*/
class ContentSecurityPolicy extends EmptyContentSecurityPolicy {
/** @var bool Whether inline JS snippets are allowed */
protected $inlineScriptAllowed = false;
/**
* @var bool Whether eval in JS scripts is allowed
* TODO: Disallow per default
* @link https://github.com/owncloud/core/issues/11925
*/
protected $evalScriptAllowed = true;
/** @var array Domains from which scripts can get loaded */
protected $allowedScriptDomains = [
'\'self\'',
];
/**
* @var bool Whether inline CSS is allowed
* TODO: Disallow per default
* @link https://github.com/owncloud/core/issues/13458
*/
protected $inlineStyleAllowed = true;
/** @var array Domains from which CSS can get loaded */
protected $allowedStyleDomains = [
'\'self\'',
];
/** @var array Domains from which images can get loaded */
protected $allowedImageDomains = [
'\'self\'',
'data:',
'blob:',
];
/** @var array Domains to which connections can be done */
protected $allowedConnectDomains = [
'\'self\'',
];
/** @var array Domains from which media elements can be loaded */
protected $allowedMediaDomains = [
'\'self\'',
];
/** @var array Domains from which object elements can be loaded */
protected $allowedObjectDomains = [];
/** @var array Domains from which iframes can be loaded */
protected $allowedFrameDomains = [];
/** @var array Domains from which fonts can be loaded */
protected $allowedFontDomains = [
'\'self\'',
];
/** @var array Domains from which web-workers and nested browsing content can load elements */
protected $allowedChildSrcDomains = [];
}