1 files changed, 23 insertions, 0 deletions
diff --git a/lib/files/storage/common.php b/lib/files/storage/common.php
index 591803f0440..ce9e7ead6d1 100644
--- a/lib/files/storage/common.php
+++ b/lib/files/storage/common.php
@@ -277,4 +277,27 @@ abstract class Common implements \OC\Files\Storage\Storage {
 			return uniqid();
 		}
 	}
+	
+	/**
+	 * clean a path, i.e. remove all redundant '.' and '..'
+	 * making sure that it can't point to higher than '/'
+	 * @param $path The path to clean
+	 * @return string cleaned path
+	 */
+	public function cleanPath($path) {
+		if (strlen($path) == 0 or $path[0] != '/') {
+			$path = '/' . $path;
+		}
+		
+		$output = array();
+		foreach (explode('/', $path) as $chunk) {
+			if ($chunk == '..') {
+				array_pop($output);
+			} else if ($chunk == '.') {
+			} else {
+				$output[] = $chunk;
+			}
+		}
+		return implode('/', $output);
+	}
 }