fix: Make forbidden filename list case insensitive again

It previously was, even if not documented, case insensitive.

Signed-off-by: Ferdinand Thiessen <opensource@fthiessen.de>

config/config.sample.php

@@ -1966,6 +1966,8 @@ $CONFIG = [
  *
  * WARNING: USE THIS ONLY IF YOU KNOW WHAT YOU ARE DOING.
  *
+ * Note that this list is case-insensitive.
+ *
  * Defaults to ``array('.htaccess')``
  */
 'blacklisted_files' => ['.htaccess'],

lib/private/Files/Filesystem.php

@@ -487,7 +487,7 @@ class Filesystem {
 		}
 
 		$forbiddenNames = \OCP\Util::getForbiddenFilenames();
-		return in_array($filename, $forbiddenNames);
+		return in_array(mb_strtolower($filename), $forbiddenNames);
 	}
 
 	/**

lib/public/Util.php

@@ -527,6 +527,7 @@ class Util {
 
 	/**
 	 * Get a list of reserved file names that must not be used
+	 * This list should be checked case-insensitive, all names are returned lowercase.
 	 * @return string[]
 	 * @since 30.0.0
 	 */
@@ -539,7 +540,7 @@ class Util {
 				\OCP\Server::get(LoggerInterface::class)->error('Invalid system config value for "blacklisted_files" is ignored.');
 				$invalidFilenames = ['.htaccess'];
 			}
-			self::$invalidFilenames = $invalidFilenames;
+			self::$invalidFilenames = array_map('mb_strtolower', $invalidFilenames);
 		}
 		return self::$invalidFilenames;
 	}

tests/lib/Files/FilesystemTest.php

@@ -284,7 +284,7 @@ class FilesystemTest extends \Test\TestCase {
 			['/etc/foo\bar/.htaccess/', true],
 			['/etc/foo\bar/.htaccess/foo', false],
 			['//foo//bar/\.htaccess/', true],
-			['\foo\bar\.htaccess', true],
+			['\foo\bar\.HTAccess', true],
 		];
 	}