3 files changed, 73 insertions, 4 deletions

diff --git a/lib/private/Security/CSP/ContentSecurityPolicyNonceManager.php b/lib/private/Security/CSP/ContentSecurityPolicyNonceManager.php
new file mode 100644
index 00000000000..0482ea49e5c
--- /dev/null
+++ b/lib/private/Security/CSP/ContentSecurityPolicyNonceManager.php
@@ -0,0 +1,54 @@
+<?php
+/**
+ * @copyright Copyright (c) 2016 Lukas Reschke <lukas@statuscode.ch>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * 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
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace OC\Security\CSP;
+
+use OC\Security\CSRF\CsrfTokenManager;
+
+/**
+ * @package OC\Security\CSP
+ */
+class ContentSecurityPolicyNonceManager {
+	/** @var CsrfTokenManager */
+	private $csrfTokenManager;
+	/** @var string */
+	private $nonce = '';
+
+	/**
+	 * @param CsrfTokenManager $csrfTokenManager
+	 */
+	public function __construct(CsrfTokenManager $csrfTokenManager) {
+		$this->csrfTokenManager = $csrfTokenManager;
+	}
+
+	/**
+	 * Returns the current CSP nounce
+	 *
+	 * @return string
+	 */
+	public function getNonce() {
+		if($this->nonce === '') {
+			$this->nonce = base64_encode($this->csrfTokenManager->getToken()->getEncryptedValue());
+		}
+
+		return $this->nonce;
+	}
+}
diff --git a/lib/private/Security/CSRF/CsrfToken.php b/lib/private/Security/CSRF/CsrfToken.php
index bf61e339f77..dce9a83b727 100644
--- a/lib/private/Security/CSRF/CsrfToken.php
+++ b/lib/private/Security/CSRF/CsrfToken.php
@@ -33,6 +33,8 @@ namespace OC\Security\CSRF;
 class CsrfToken {
 	/** @var string */
 	private $value;
+	/** @var string */
+	private $encryptedValue = '';
 
 	/**
 	 * @param string $value Value of the token. Can be encrypted or not encrypted.
@@ -48,8 +50,12 @@ class CsrfToken {
 	 * @return string
 	 */
 	public function getEncryptedValue() {
-		$sharedSecret = base64_encode(random_bytes(strlen($this->value)));
-		return base64_encode($this->value ^ $sharedSecret) .':'.$sharedSecret;
+		if($this->encryptedValue === '') {
+			$sharedSecret = base64_encode(random_bytes(strlen($this->value)));
+			$this->encryptedValue = base64_encode($this->value ^ $sharedSecret) . ':' . $sharedSecret;
+		}
+
+		return $this->encryptedValue;
 	}
 
 	/**
diff --git a/lib/private/Security/CSRF/CsrfTokenManager.php b/lib/private/Security/CSRF/CsrfTokenManager.php
index d621cc2c29f..b43ca3d3679 100644
--- a/lib/private/Security/CSRF/CsrfTokenManager.php
+++ b/lib/private/Security/CSRF/CsrfTokenManager.php
@@ -34,6 +34,8 @@ class CsrfTokenManager {
 	private $tokenGenerator;
 	/** @var SessionStorage */
 	private $sessionStorage;
+	/** @var CsrfToken|null */
+	private $csrfToken = null;
 
 	/**
 	 * @param CsrfTokenGenerator $tokenGenerator
@@ -51,6 +53,10 @@ class CsrfTokenManager {
 	 * @return CsrfToken
 	 */
 	public function getToken() {
+		if(!is_null($this->csrfToken)) {
+			return $this->csrfToken;
+		}
+
 		if($this->sessionStorage->hasToken()) {
 			$value = $this->sessionStorage->getToken();
 		} else {
@@ -58,7 +64,8 @@ class CsrfTokenManager {
 			$this->sessionStorage->setToken($value);
 		}
 
-		return new CsrfToken($value);
+		$this->csrfToken = new CsrfToken($value);
+		return $this->csrfToken;
 	}
 
 	/**
@@ -69,13 +76,15 @@ class CsrfTokenManager {
 	public function refreshToken() {
 		$value = $this->tokenGenerator->generateToken();
 		$this->sessionStorage->setToken($value);
-		return new CsrfToken($value);
+		$this->csrfToken = new CsrfToken($value);
+		return $this->csrfToken;
 	}
 
 	/**
 	 * Remove the current token from the storage.
 	 */
 	public function removeToken() {
+		$this->csrfToken = null;
 		$this->sessionStorage->removeToken();
 	}