https://github.com/python/cpython/commit/dcd2dbaf36ef8cb577b6c4f4117ba1822cecc375 commit: dcd2dbaf36ef8cb577b6c4f4117ba1822cecc375 branch: 3.13 author: Miss Islington (bot) <[email protected]> committer: picnixz <[email protected]> date: 2025-11-07T10:18:06Z summary:
[3.13] gh-140734: fix off-by-one error when comparing to `_SUN_PATH_MAX` (GH-140903) (#141182) gh-140734: fix off-by-one error when comparing to `_SUN_PATH_MAX` (GH-140903) The limit includes a NULL terminator. (cherry picked from commit 9a199006733dae999f96c0f596c2035f4b9847b2) Co-authored-by: Bénédikt Tran <[email protected]> files: A Misc/NEWS.d/next/Library/2025-11-02-09-37-22.gh-issue-140734.f8gST9.rst M Lib/multiprocessing/util.py diff --git a/Lib/multiprocessing/util.py b/Lib/multiprocessing/util.py index e7e48c65f7a4be..b8bfea045df925 100644 --- a/Lib/multiprocessing/util.py +++ b/Lib/multiprocessing/util.py @@ -126,12 +126,14 @@ def is_abstract_socket_namespace(address): # Function returning a temp directory which will be removed on exit # -# Maximum length of a socket file path is usually between 92 and 108 [1], -# but Linux is known to use a size of 108 [2]. BSD-based systems usually -# use a size of 104 or 108 and Windows does not create AF_UNIX sockets. +# Maximum length of a NULL-terminated [1] socket file path is usually +# between 92 and 108 [2], but Linux is known to use a size of 108 [3]. +# BSD-based systems usually use a size of 104 or 108 and Windows does +# not create AF_UNIX sockets. # -# [1]: https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/sys_un.h.html -# [2]: https://man7.org/linux/man-pages/man7/unix.7.html. +# [1]: https://github.com/python/cpython/issues/140734 +# [2]: https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/sys_un.h.html +# [3]: https://man7.org/linux/man-pages/man7/unix.7.html if sys.platform == 'linux': _SUN_PATH_MAX = 108 @@ -171,11 +173,13 @@ def _get_base_temp_dir(tempfile): # generated by tempfile._RandomNameSequence, which, by design, # is 8 characters long. # - # Thus, the length of socket filename will be: + # Thus, the socket file path length (without NULL terminator) will be: # # len(base_tempdir + '/pymp-XXXXXXXX' + '/sock-XXXXXXXX') sun_path_len = len(base_tempdir) + 14 + 14 - if sun_path_len <= _SUN_PATH_MAX: + # Strict inequality to account for the NULL terminator. + # See https://github.com/python/cpython/issues/140734. + if sun_path_len < _SUN_PATH_MAX: return base_tempdir # Fallback to the default system-wide temporary directory. # This ignores user-defined environment variables. @@ -201,7 +205,7 @@ def _get_base_temp_dir(tempfile): return base_tempdir _warn("Ignoring user-defined temporary directory: %s", base_tempdir) # at most max(map(len, dirlist)) + 14 + 14 = 36 characters - assert len(base_system_tempdir) + 14 + 14 <= _SUN_PATH_MAX + assert len(base_system_tempdir) + 14 + 14 < _SUN_PATH_MAX return base_system_tempdir def get_temp_dir(): diff --git a/Misc/NEWS.d/next/Library/2025-11-02-09-37-22.gh-issue-140734.f8gST9.rst b/Misc/NEWS.d/next/Library/2025-11-02-09-37-22.gh-issue-140734.f8gST9.rst new file mode 100644 index 00000000000000..46582f7fcf417c --- /dev/null +++ b/Misc/NEWS.d/next/Library/2025-11-02-09-37-22.gh-issue-140734.f8gST9.rst @@ -0,0 +1,2 @@ +:mod:`multiprocessing`: fix off-by-one error when checking the length +of a temporary socket file path. Patch by Bénédikt Tran. _______________________________________________ Python-checkins mailing list -- [email protected] To unsubscribe send an email to [email protected] https://mail.python.org/mailman3//lists/python-checkins.python.org Member address: [email protected]
