Fix: raise error on neg size in PyBytes_FromStringAndSize

Author: fangerer

graalpython/com.oracle.graal.python.cext/src/bytesobject.c

@@ -58,10 +58,14 @@ Py_ssize_t PyBytes_Size(PyObject *bytes) {
 UPCALL_ID(PyBytes_FromStringAndSize);
 UPCALL_ID(PyTruffle_Bytes_EmptyWithCapacity);
 PyObject* PyBytes_FromStringAndSize(const char* str, Py_ssize_t sz) {
-	if (str != NULL) {
-		return ((fromStringAndSize_fun_t)_jls_PyBytes_FromStringAndSize)(polyglot_from_i8_array(str, sz), sz);
-	}
-	return UPCALL_CEXT_O(_jls_PyTruffle_Bytes_EmptyWithCapacity, sz);
+    if (sz < 0) {
+        PyErr_SetString(PyExc_SystemError, "Negative size passed to PyBytes_FromStringAndSize");
+        return NULL;
+    }
+    if (str != NULL) {
+        return ((fromStringAndSize_fun_t)_jls_PyBytes_FromStringAndSize)(polyglot_from_i8_array(str, sz), sz);
+    }
+    return UPCALL_CEXT_O(_jls_PyTruffle_Bytes_EmptyWithCapacity, sz);
 }
 
 PyObject * PyBytes_FromString(const char *str) {