multiprocessing.connection.Listener fails to close with null byte in AF_UNIX socket name.

[nmichaels]

BPO	39850
Nosy	@pitrou, @pablogsal
PRs	bpo-39850: Add support for abstract sockets in multiprocessing #18866 [3.8] bpo-39850: Add support for abstract sockets in multiprocessing (GH-18866) #18876 [3.7]bpo-39850: Add support for abstract sockets in multiprocessing (GH-18866) #18877

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

Show more details

GitHub fields:

assignee = None
closed_at = <Date 2020-03-09.14:48:23.277>
created_at = <Date 2020-03-04.16:12:51.698>
labels = ['3.7', '3.8', 'type-bug', 'library', '3.9']
title = 'multiprocessing.connection.Listener fails to close with null byte in AF_UNIX socket name.'
updated_at = <Date 2020-03-09.14:48:23.277>
user = 'https://bugs.python.org/nmichaels'

bugs.python.org fields:

activity = <Date 2020-03-09.14:48:23.277>
actor = 'pablogsal'
assignee = 'none'
closed = True
closed_date = <Date 2020-03-09.14:48:23.277>
closer = 'pablogsal'
components = ['Library (Lib)']
creation = <Date 2020-03-04.16:12:51.698>
creator = 'nmichaels'
dependencies = []
files = []
hgrepos = []
issue_num = 39850
keywords = ['patch']
message_count = 4.0
messages = ['363357', '363730', '363737', '363738']
nosy_count = 3.0
nosy_names = ['pitrou', 'nmichaels', 'pablogsal']
pr_nums = ['18866', '18876', '18877']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue39850'
versions = ['Python 3.7', 'Python 3.8', 'Python 3.9']

[nmichaels]

>>> from multiprocessing.connection import Listener
>>> listener = Listener('\0conntest', family='AF_UNIX')
>>> listener.close()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib64/python3.6/multiprocessing/connection.py", line 466, in close
    listener.close()
  File "/usr/lib64/python3.6/multiprocessing/connection.py", line 604, in close
    unlink()
  File "/usr/lib64/python3.6/multiprocessing/util.py", line 186, in __call__
    res = self._callback(*self._args, **self._kwargs)
ValueError: embedded null byte

Linux has a handy feature where if the first byte of a unix domain socket's name is the null character, it won't put it in the filesystem. The socket interface works fine with it, but when SocketListener is wrapped around a socket, it throws this exception.

[pablogsal]

New changeset 6012f30 by Pablo Galindo in branch 'master':
bpo-39850: Add support for abstract sockets in multiprocessing (GH-18866)
6012f30

[pablogsal]

New changeset 2235e04 by Pablo Galindo in branch '3.7':
[3.7] bpo-39850: Add support for abstract sockets in multiprocessing (GH-18866) (GH-18877)
2235e04

[pablogsal]

New changeset 3ede1bc by Pablo Galindo in branch '3.8':
[3.8] bpo-39850: Add support for abstract sockets in multiprocessing (GH-18866) (GH-18876)
3ede1bc

[gpshead]

Now that it's public... if you are explicitly asking multiprocessing to use Linux abstract sockets in your code you likely have a security problem: #97514