Added extra checks for invalid file chars in newfile.php and newfolder.php

- added PHP utility function to check for file name validity
- fixes issue where a user can create a file called ".." from the files UI
- added extra checks to make sure newfile.php and newfolder.php also
  check for invalid characters

apps/files/ajax/newfile.php

@@ -50,16 +50,22 @@ $l10n = \OC_L10n::get('files');
 $result = array(
 	'success' 	=> false,
 	'data'		=> NULL
-	);
+);
+$trimmedFileName = trim($filename);
 
-if(trim($filename) === '') {
+if($trimmedFileName === '') {
 	$result['data'] = array('message' => (string)$l10n->t('File name cannot be empty.'));
 	OCP\JSON::error($result);
 	exit();
 }
+if($trimmedFileName === '.' || $trimmedFileName === '..') {
+	$result['data'] = array('message' => (string)$l10n->t('"%s" is an invalid file name.', $trimmedFileName));
+	OCP\JSON::error($result);
+	exit();
+}
 
-if(strpos($filename, '/') !== false) {
-	$result['data'] = array('message' => (string)$l10n->t('File name must not contain "/". Please choose a different name.'));
+if(!OCP\Util::isValidFileName($filename)) {
+	$result['data'] = array('message' => (string)$l10n->t("Invalid name, '\\', '/', '<', '>', ':', '\"', '|', '?' and '*' are not allowed."));
 	OCP\JSON::error($result);
 	exit();
 }

apps/files/ajax/newfolder.php

@@ -23,8 +23,8 @@ if(trim($foldername) === '') {
 	exit();
 }
 
-if(strpos($foldername, '/') !== false) {
-	$result['data'] = array('message' => $l10n->t('Folder name must not contain "/". Please choose a different name.'));
+if(!OCP\Util::isValidFileName($foldername)) {
+	$result['data'] = array('message' => (string)$l10n->t("Invalid name, '\\', '/', '<', '>', ':', '\"', '|', '?' and '*' are not allowed."));
 	OCP\JSON::error($result);
 	exit();
 }

lib/private/util.php

@@ -1149,4 +1149,25 @@ class OC_Util {
 		}
 		return $version;
 	}
+
+	/**
+	 * Returns whether the given file name is valid
+	 * @param $file string file name to check
+	 * @return bool true if the file name is valid, false otherwise
+	 */
+	public static function isValidFileName($file) {
+		$trimmed = trim($file);
+		if ($trimmed === '') {
+			return false;
+		}
+		if ($trimmed === '.' || $trimmed === '..') {
+			return false;
+		}
+		foreach (str_split($trimmed) as $char) {
+			if (strpos(\OCP\FILENAME_INVALID_CHARS, $char) !== false) {
+				return false;
+			}
+		}
+		return true;
+	}
 }

lib/public/constants.php

@@ -35,3 +35,6 @@ const PERMISSION_UPDATE = 2;
 const PERMISSION_DELETE = 8;
 const PERMISSION_SHARE = 16;
 const PERMISSION_ALL = 31;
+
+const FILENAME_INVALID_CHARS = "\\/<>:\"|?*\n";
+

lib/public/util.php

@@ -486,4 +486,13 @@ class Util {
 	public static function uploadLimit() {
 		return \OC_Helper::uploadLimit();
 	}
+
+	/**
+	 * Returns whether the given file name is valid
+	 * @param $file string file name to check
+	 * @return bool true if the file name is valid, false otherwise
+	 */
+	public static function isValidFileName($file) {
+		return \OC_Util::isValidFileName($file);
+	}
 }

tests/lib/util.php

@@ -170,4 +170,52 @@ class Test_Util extends PHPUnit_Framework_TestCase {
 			array('442aa682de2a64db1e010f50e60fd9c9', 'local::C:\Users\ADMINI~1\AppData\Local\Temp\2/442aa682de2a64db1e010f50e60fd9c9/')
 		);
 	}
+
+	/**
+	 * @dataProvider filenameValidationProvider
+	 */
+	public function testFilenameValidation($file, $valid) {
+		// private API
+		$this->assertEquals($valid, \OC_Util::isValidFileName($file));
+		// public API
+		$this->assertEquals($valid, \OCP\Util::isValidFileName($file));
+	}
+
+	public function filenameValidationProvider() {
+		return array(
+			// valid names
+			array('boringname', true),
+			array('something.with.extension', true),
+			array('now with spaces', true),
+			array('.a', true),
+			array('..a', true),
+			array('.dotfile', true),
+			array('single\'quote', true),
+			array('  spaces before', true),
+			array('spaces after   ', true),
+			array('allowed chars including the crazy ones $%&_-^@!,()[]{}=;#', true),
+			array('汉字也能用', true),
+			array('und Ümläüte sind auch willkommen', true),
+			// disallowed names
+			array('', false),
+			array('     ', false),
+			array('.', false),
+			array('..', false),
+			array('back\\slash', false),
+			array('sl/ash', false),
+			array('lt<lt', false),
+			array('gt>gt', false),
+			array('col:on', false),
+			array('double"quote', false),
+			array('pi|pe', false),
+			array('dont?ask?questions?', false),
+			array('super*star', false),
+			array('new\nline', false),
+			// better disallow these to avoid unexpected trimming to have side effects
+			array(' ..', false),
+			array('.. ', false),
+			array('. ', false),
+			array(' .', false),
+		);
+	}
 }