add SSL proxy support

Add support for a reverse proxy that only forwards SSL connections
unencrypted to the web server.

This patch allows to detect the reverse proxy via regular expression for
the remote IP address and conditional overwrite the host name, protocol
and web root.

2 files changed, 16 insertions, 4 deletions

diff --git a/config/config.sample.php b/config/config.sample.php
index ebe73fbec7b..5264e948200 100644
--- a/config/config.sample.php
+++ b/config/config.sample.php
@@ -41,6 +41,9 @@ $CONFIG = array(
 /* The automatic webroot detection of ownCloud can fail in certain reverse proxy situations. This option allows to manually override the automatic detection. For example "/domain.tld/ownCloud" */
 "overwritewebroot" => "",
 
+/* The automatic detection of ownCloud can fail in certain reverse proxy situations. This option allows to define a manually override condition as regular expression for the remote ip address. For example "^10\.0\.0\.[1-3]$" */
+"overwritecondaddr" => "",
+
 /* A proxy to use to connect to the internet. For example "myproxy.org:88" */
 "proxy" => "",
 
diff --git a/lib/request.php b/lib/request.php
index 4c056ce9b2f..1661a1406ca 100755
--- a/lib/request.php
+++ b/lib/request.php
@@ -8,6 +8,15 @@
 
 class OC_Request {
 	/**
+	 * @brief Check overwrite condition
+	 * @returns true/false
+	 */
+	private static function isOverwriteCondition() {
+		$regex = '/' . OC_Config::getValue('overwritecondaddr', '')  . '/';
+		return $regex === '//' or preg_match($regex, $_SERVER['REMOTE_ADDR']) === 1;
+	}
+
+	/**
 	 * @brief Returns the server host
 	 * @returns the server host
 	 *
@@ -18,7 +27,7 @@ class OC_Request {
 		if(OC::$CLI) {
 			return 'localhost';
 		}
-		if(OC_Config::getValue('overwritehost', '')<>'') {
+		if(OC_Config::getValue('overwritehost', '')<>'' and self::isOverwriteCondition()) {
 			return OC_Config::getValue('overwritehost');
 		}
 		if (isset($_SERVER['HTTP_X_FORWARDED_HOST'])) {
@@ -43,7 +52,7 @@ class OC_Request {
 	* Returns the server protocol. It respects reverse proxy servers and load balancers
 	*/
 	public static function serverProtocol() {
-		if(OC_Config::getValue('overwriteprotocol', '')<>'') {
+		if(OC_Config::getValue('overwriteprotocol', '')<>'' and self::isOverwriteCondition()) {
 			return OC_Config::getValue('overwriteprotocol');
 		}
 		if (isset($_SERVER['HTTP_X_FORWARDED_PROTO'])) {
@@ -67,7 +76,7 @@ class OC_Request {
 	 */
 	public static function requestUri() {
 		$uri = isset($_SERVER['REQUEST_URI']) ? $_SERVER['REQUEST_URI'] : '';
-		if (OC_Config::getValue('overwritewebroot', '') <> '') {
+		if (OC_Config::getValue('overwritewebroot', '') <> '' and self::isOverwriteCondition()) {
 			$uri = self::scriptName() . substr($uri, strlen($_SERVER['SCRIPT_NAME']));
 		}
 		return $uri;
@@ -82,7 +91,7 @@ class OC_Request {
 	 */
 	public static function scriptName() {
 		$name = $_SERVER['SCRIPT_NAME'];
-		if (OC_Config::getValue('overwritewebroot', '') <> '') {
+		if (OC_Config::getValue('overwritewebroot', '') <> '' and self::isOverwriteCondition()) {
 			$serverroot = str_replace("\\", '/', substr(__DIR__, 0, -4));
 			$suburi = str_replace("\\", "/", substr(realpath($_SERVER["SCRIPT_FILENAME"]), strlen($serverroot)));
 			$name = OC_Config::getValue('overwritewebroot', '') . $suburi;