1 files changed, 75 insertions, 0 deletions
diff --git a/lib/private/security/trusteddomainhelper.php b/lib/private/security/trusteddomainhelper.php
new file mode 100644
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+++ b/lib/private/security/trusteddomainhelper.php
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+<?php
+/**
+ * Copyright (c) 2015 Lukas Reschke <lukas@owncloud.com>
+ * This file is licensed under the Affero General Public License version 3 or
+ * later.
+ * See the COPYING-README file.
+ */
+
+namespace OC\Security;
+use OC\AppFramework\Http\Request;
+use OCP\IConfig;
+
+/**
+ * Class TrustedDomain
+ *
+ * @package OC\Security
+ */
+class TrustedDomainHelper {
+	/** @var IConfig */
+	private $config;
+
+	/**
+	 * @param IConfig $config
+	 */
+	function __construct(IConfig $config) {
+		$this->config = $config;
+	}
+
+	/**
+	 * Strips a potential port from a domain (in format domain:port)
+	 * @param $host
+	 * @return string $host without appended port
+	 */
+	private function getDomainWithoutPort($host) {
+		$pos = strrpos($host, ':');
+		if ($pos !== false) {
+			$port = substr($host, $pos + 1);
+			if (is_numeric($port)) {
+				$host = substr($host, 0, $pos);
+			}
+		}
+		return $host;
+	}
+
+	/**
+	 * Checks whether a domain is considered as trusted from the list
+	 * of trusted domains. If no trusted domains have been configured, returns
+	 * true.
+	 * This is used to prevent Host Header Poisoning.
+	 * @param string $domainWithPort
+	 * @return bool true if the given domain is trusted or if no trusted domains
+	 * have been configured
+	 */
+	public function isTrustedDomain($domainWithPort) {
+		$domain = $this->getDomainWithoutPort($domainWithPort);
+
+		// Read trusted domains from config
+		$trustedList = $this->config->getSystemValue('trusted_domains', []);
+		if(!is_array($trustedList)) {
+			return false;
+		}
+
+		// TODO: Workaround for older instances still with port applied. Remove for ownCloud 9.
+		if(in_array($domainWithPort, $trustedList)) {
+			return true;
+		}
+
+		// Always allow access from localhost
+		if (preg_match(Request::REGEX_LOCALHOST, $domain) === 1) {
+			return true;
+		}
+		return in_array($domain, $trustedList);
+	}
+
+}