if family == 'AF_INET':

return ('localhost', 0)

elif family == 'AF_UNIX':

# Prefer abstract sockets if possible to avoid problems with the address

# size. When coding portable applications, some implementations have

# sun_path as short as 92 bytes in the sockaddr_un struct.

if util.abstract_sockets_supported:

return f"\0listener-{os.getpid()}-{next(_mmap_counter)}"

return tempfile.mktemp(prefix='listener-', dir=util.get_temp_dir())

elif family == 'AF_PIPE':

return tempfile.mktemp(prefix=r'\\.\pipe\pyc-%d-%d-' %

On Linux the :mod:`multiprocessing` module returns to using filesystem backed

unix domain sockets for communication with the *forkserver* process instead of

the Linux abstract socket namespace. Only code that chooses to use the

:ref:`"forkserver" start method <multiprocessing-start-methods>` is affected.

Abstract sockets have no permissions and could allow any user on the system in

the same `network namespace

<https://man7.org/linux/man-pages/man7/network_namespaces.7.html>`_ (often the

whole system) to inject code into the multiprocessing *forkserver* process.

This was a potential privilege escalation. Filesystem based socket permissions

restrict this to the *forkserver* process user as was the default in Python 3.8

and earlier.

This prevents Linux `CVE-2022-42919

<https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-42919>`_.