Fix a potential memory denial of service when reading from a file, a file descriptor or a buffered stream the large specific number of bytes. This affects the :func:`os.read` and :func:`os.pread` functions and the :meth:`!read` and :meth:`!read1` methods of various :mod:`io` classes. When the number of bytes to read is received from untrusted source, it could cause an arbitrary amount of memory to be allocated. This could have led to symptoms including a :exc:`MemoryError`, swapping, out of memory (OOM) killed processes or containers, or even system crashes.