python3: fix CVE-2022-42919 local privilege escalation via the multiprocessing forkserver start method

Upstream-Status: Backport from https://github.com/python/cpython/commit/eae692eed18892309bcc25a2c0f8980038305ea2

(From OE-Core rev: 9ed7184930707c98afabca8c6b712df874ad659f)

Signed-off-by: Vivek Kumbhar <vkumbhar@mvista.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 70 insertions, 0 deletions

diff --git a/meta/recipes-devtools/python/python3/CVE-2022-42919.patch b/meta/recipes-devtools/python/python3/CVE-2022-42919.patch
new file mode 100644
index 0000000000..6040724dae
--- /dev/null
+++ b/meta/recipes-devtools/python/python3/CVE-2022-42919.patch
@@ -0,0 +1,70 @@
+From 87ef80926ea0ec960a220af89d8ff4db99417b03 Mon Sep 17 00:00:00 2001
+From: Vivek Kumbhar <vkumbhar@mvista.com>
+Date: Thu, 24 Nov 2022 17:44:18 +0530
+Subject: [PATCH] CVE-2022-42919
+
+Upstream-Status: Backport [https://github.com/python/cpython/commit/eae692eed18892309bcc25a2c0f8980038305ea2]
+CVE: CVE-2022-42919
+Signed-off-by: Vivek Kumbhar <vkumbhar@mvista.com>
+
+[3.10] gh-97514: Don't use Linux abstract sockets for multiprocessing (GH-98501) (GH-98503)
+
+Linux abstract sockets are insecure as they lack any form of filesystem
+permissions so their use allows anyone on the system to inject code into
+the process.
+
+This removes the default preference for abstract sockets in
+multiprocessing introduced in Python 3.9+ via
+https://github.com/python/cpython/pull/18866 while fixing
+https://github.com/python/cpython/issues/84031.
+
+Explicit use of an abstract socket by a user now generates a
+RuntimeWarning.  If we choose to keep this warning, it should be
+backported to the 3.7 and 3.8 branches.
+(cherry picked from commit 49f61068f49747164988ffc5a442d2a63874fc17)
+---
+ Lib/multiprocessing/connection.py                 |  5 -----
+ .../2022-09-07-10-42-00.gh-issue-97514.Yggdsl.rst | 15 +++++++++++++++
+ 2 files changed, 15 insertions(+), 5 deletions(-)
+ create mode 100644 Misc/NEWS.d/next/Security/2022-09-07-10-42-00.gh-issue-97514.Yggdsl.rst
+
+diff --git a/Lib/multiprocessing/connection.py b/Lib/multiprocessing/connection.py
+index 510e4b5..8e2facf 100644
+--- a/Lib/multiprocessing/connection.py
++++ b/Lib/multiprocessing/connection.py
+@@ -73,11 +73,6 @@ def arbitrary_address(family):
+     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-' %
+diff --git a/Misc/NEWS.d/next/Security/2022-09-07-10-42-00.gh-issue-97514.Yggdsl.rst b/Misc/NEWS.d/next/Security/2022-09-07-10-42-00.gh-issue-97514.Yggdsl.rst
+new file mode 100644
+index 0000000..02d95b5
+--- /dev/null
++++ b/Misc/NEWS.d/next/Security/2022-09-07-10-42-00.gh-issue-97514.Yggdsl.rst
+@@ -0,0 +1,15 @@
++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>`_.
+-- 
+2.25.1
+