fix permision mask applying outside home directory for cache entries

fixes #113

lib/Storage/DirMask.php

@@ -21,6 +21,7 @@
 
 namespace OCA\Guests\Storage;
 
+use OC\Files\Cache\Wrapper\CachePermissionsMask;
 use OC\Files\Storage\Wrapper\PermissionsMask;
 
 
@@ -41,6 +42,8 @@ class DirMask extends PermissionsMask {
 	 */
 	private $pathLength;
 
+	private $mask;
+
 	/**
 	 * @param array $arguments ['storage' => $storage, 'mask' => $mask, 'path' => $path]
 	 *
@@ -52,6 +55,7 @@ public function __construct($arguments) {
 		parent::__construct($arguments);
 		$this->path = $arguments['path'];
 		$this->pathLength = strlen($arguments['path']);
+		$this->mask = $arguments['mask'];
 	}
 
 	protected function checkPath($path) {
@@ -185,4 +189,12 @@ public function fopen($path, $mode) {
 			return $this->storage->fopen($path, $mode);
 		}
 	}
+
+	public function getCache($path = '', $storage = null) {
+		if (!$storage) {
+			$storage = $this;
+		}
+		$sourceCache = $this->storage->getCache($path, $storage);
+		return new DirMaskCache($sourceCache, $this->mask, [$this, 'checkPath']);
+	}
 }

lib/Storage/DirMaskCache.php

@@ -0,0 +1,48 @@
+<?php declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2019 Robin Appelman <[email protected]>
+ *
+ * @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 OCA\Guests\Storage;
+
+
+use OC\Files\Cache\Wrapper\CachePermissionsMask;
+
+class DirMaskCache extends CachePermissionsMask {
+
+	private $checkPath;
+
+	/**
+	 * @param \OCP\Files\Cache\ICache $cache
+	 * @param int $mask
+	 */
+	public function __construct($cache, $mask, callable $checkPath) {
+		parent::__construct($cache, $mask);
+		$this->checkPath = $checkPath;
+	}
+
+	protected function formatCacheEntry($entry) {
+		$checkPath = $this->checkPath;
+		if ($checkPath($entry['path'])) {
+			return parent::formatCacheEntry($entry);
+		}
+		return $entry;
+	}
+
+}