nextcloud/lib/private/Security/CSRF/CsrfTokenManager.php

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<?php
declare(strict_types=1);
/**
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* @copyright Copyright (c) 2016, ownCloud, Inc.
*
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* @author Lukas Reschke <lukas@statuscode.ch>
*
* @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 OC\Security\CSRF;
use OC\Security\CSRF\TokenStorage\SessionStorage;
/**
* Class CsrfTokenManager is the manager for all CSRF token related activities.
*
* @package OC\Security\CSRF
*/
class CsrfTokenManager {
/** @var CsrfTokenGenerator */
private $tokenGenerator;
/** @var SessionStorage */
private $sessionStorage;
Add support for CSP nonces CSP nonces are a feature available with CSP v2. Basically instead of saying "JS resources from the same domain are ok to be served" we now say "Ressources from everywhere are allowed as long as they add a `nonce` attribute to the script tag with the right nonce. At the moment the nonce is basically just a `<?php p(base64_encode($_['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>
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/** @var CsrfToken|null */
private $csrfToken = null;
/**
* @param CsrfTokenGenerator $tokenGenerator
* @param SessionStorage $storageInterface
*/
public function __construct(CsrfTokenGenerator $tokenGenerator,
SessionStorage $storageInterface) {
$this->tokenGenerator = $tokenGenerator;
$this->sessionStorage = $storageInterface;
}
/**
* Returns the current CSRF token, if none set it will create a new one.
*
* @return CsrfToken
*/
public function getToken(): CsrfToken {
if(!\is_null($this->csrfToken)) {
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>
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return $this->csrfToken;
}
if($this->sessionStorage->hasToken()) {
$value = $this->sessionStorage->getToken();
} else {
$value = $this->tokenGenerator->generateToken();
$this->sessionStorage->setToken($value);
}
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($_['requesttoken'])) ?>`, we have to decode the requesttoken since `:` is not an allowed value in the nonce. So if somebody does on their own include JS files (instead of using the `addScript` public API, they now must also include that attribute.) IE does currently not implement CSP v2, thus there is a whitelist included that delivers the new CSP v2 policy to newer browsers. Check http://caniuse.com/#feat=contentsecuritypolicy2 for the current browser support list. An alternative approach would be to just add `'unsafe-inline'` as well as `'unsafe-inline'` is ignored by CSPv2 when a nonce is set. But this would make this security feature unusable at all in IE. Not worth it at the moment IMO. Implementing this offers the following advantages: 1. **Security:** As we host resources from the same domain by design we don't have to worry about 'self' anymore being in the whitelist 2. **Performance:** We can move oc.js again to inline JS. This makes the loading way quicker as we don't have to load on every load of a new web page a blocking dynamically non-cached JavaScript file. If you want to toy with CSP see also https://csp-evaluator.withgoogle.com/ Signed-off-by: Lukas Reschke <lukas@statuscode.ch>
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$this->csrfToken = new CsrfToken($value);
return $this->csrfToken;
}
/**
* Invalidates any current token and sets a new one.
*
* @return CsrfToken
*/
public function refreshToken(): CsrfToken {
$value = $this->tokenGenerator->generateToken();
$this->sessionStorage->setToken($value);
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($_['requesttoken'])) ?>`, we have to decode the requesttoken since `:` is not an allowed value in the nonce. So if somebody does on their own include JS files (instead of using the `addScript` public API, they now must also include that attribute.) IE does currently not implement CSP v2, thus there is a whitelist included that delivers the new CSP v2 policy to newer browsers. Check http://caniuse.com/#feat=contentsecuritypolicy2 for the current browser support list. An alternative approach would be to just add `'unsafe-inline'` as well as `'unsafe-inline'` is ignored by CSPv2 when a nonce is set. But this would make this security feature unusable at all in IE. Not worth it at the moment IMO. Implementing this offers the following advantages: 1. **Security:** As we host resources from the same domain by design we don't have to worry about 'self' anymore being in the whitelist 2. **Performance:** We can move oc.js again to inline JS. This makes the loading way quicker as we don't have to load on every load of a new web page a blocking dynamically non-cached JavaScript file. If you want to toy with CSP see also https://csp-evaluator.withgoogle.com/ Signed-off-by: Lukas Reschke <lukas@statuscode.ch>
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$this->csrfToken = new CsrfToken($value);
return $this->csrfToken;
}
/**
* Remove the current token from the storage.
*/
public function removeToken() {
Add support for CSP nonces CSP nonces are a feature available with CSP v2. Basically instead of saying "JS resources from the same domain are ok to be served" we now say "Ressources from everywhere are allowed as long as they add a `nonce` attribute to the script tag with the right nonce. At the moment the nonce is basically just a `<?php p(base64_encode($_['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>
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$this->csrfToken = null;
$this->sessionStorage->removeToken();
}
/**
* Verifies whether the provided token is valid.
*
* @param CsrfToken $token
* @return bool
*/
public function isTokenValid(CsrfToken $token): bool {
if(!$this->sessionStorage->hasToken()) {
return false;
}
return hash_equals(
$this->sessionStorage->getToken(),
$token->getDecryptedValue()
);
}
}