Fix #78863: DirectoryIterator class silently truncates after a null byte

Since the constructor of DirectoryIterator and friends is supposed to
accepts paths (i.e. strings without NUL bytes), we must not accept
arbitrary strings.

ext/spl/spl_directory.c

@@ -708,10 +708,10 @@ void spl_filesystem_object_construct(INTERNAL_FUNCTION_PARAMETERS, zend_long cto
 
 	if (SPL_HAS_FLAG(ctor_flags, DIT_CTOR_FLAGS)) {
 		flags = SPL_FILE_DIR_KEY_AS_PATHNAME|SPL_FILE_DIR_CURRENT_AS_FILEINFO;
-		parsed = zend_parse_parameters(ZEND_NUM_ARGS(), "s|l", &path, &len, &flags);
+		parsed = zend_parse_parameters(ZEND_NUM_ARGS(), "p|l", &path, &len, &flags);
 	} else {
 		flags = SPL_FILE_DIR_KEY_AS_PATHNAME|SPL_FILE_DIR_CURRENT_AS_SELF;
-		parsed = zend_parse_parameters(ZEND_NUM_ARGS(), "s", &path, &len);
+		parsed = zend_parse_parameters(ZEND_NUM_ARGS(), "p", &path, &len);
 	}
 	if (SPL_HAS_FLAG(ctor_flags, SPL_FILE_DIR_SKIPDOTS)) {
 		flags |= SPL_FILE_DIR_SKIPDOTS;

ext/spl/tests/bug78863.phpt

@@ -0,0 +1,31 @@
+--TEST--
+Bug #78863 (DirectoryIterator class silently truncates after a null byte)
+--FILE--
+<?php
+$dir = __DIR__ . '/bug78863';
+mkdir($dir);
+touch("$dir/bad");
+mkdir("$dir/sub");
+touch("$dir/sub/good");
+
+$it = new DirectoryIterator(__DIR__ . "/bug78863\0/sub");
+foreach ($it as $fileinfo) {
+    if (!$fileinfo->isDot()) {
+        var_dump($fileinfo->getFilename());
+    }
+}
+?>
+--EXPECTF--
+Fatal error: Uncaught UnexpectedValueException: DirectoryIterator::__construct() expects parameter 1 to be a valid path, string given in %s:%d
+Stack trace:
+#0 %s(%d): DirectoryIterator->__construct('%s')
+#1 {main}
+  thrown in %s on line %d
+--CLEAN--
+<?php
+$dir = __DIR__ . '/bug78863';
+unlink("$dir/sub/good");
+rmdir("$dir/sub");
+unlink("$dir/bad");
+rmdir($dir);
+?>