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Bug 2172416 - Backport from_buffer(..., require_writable=True) for python-cryptography CVE-2023-23931 fix [rhel-8.9]
Summary: Backport from_buffer(..., require_writable=True) for python-cryptography CVE-...
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 8
Classification: Red Hat
Component: python-cffi
Version: 8.8
Hardware: Unspecified
OS: Unspecified
unspecified
unspecified
Target Milestone: rc
: ---
Assignee: Christian Heimes
QA Contact: ipa-qe
URL:
Whiteboard:
Depends On:
Blocks: 2172404
TreeView+ depends on / blocked
 
Reported: 2023-02-22 10:45 UTC by Christian Heimes
Modified: 2023-11-14 17:59 UTC (History)
6 users (show)

Fixed In Version: python-cffi-1.11.5-6.el8
Doc Type: No Doc Update
Doc Text:
Clone Of:
Environment:
Last Closed: 2023-11-14 15:48:23 UTC
Type: Bug
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Issue Tracker FREEIPA-9492 0 None None None 2023-02-22 10:46:37 UTC
Red Hat Issue Tracker RHELPLAN-149627 0 None None None 2023-02-22 10:46:40 UTC
Red Hat Product Errata RHBA-2023:7095 0 None None None 2023-11-14 15:48:26 UTC

Description Christian Heimes 2023-02-22 10:45:13 UTC 
Description of problem:
cffi 1.12 added a new keyword argument "require_writable=True" to its from_buffer() API. The feature is required to fix python-cryptography CVE-2023-23931.

Version-Release number of selected component (if applicable):
python3-cffi-1.11.5-5.el8

How reproducible:
always

Steps to Reproduce:
$ python3
>>> from cryptography.hazmat.backends.openssl import backend
>>> b = b'bytes'
>>> buf = backend._ffi.from_buffer(b)
>>> buf[0] = b'a'
>>> b
b'aytes'
>>> buf = backend._ffi.from_buffer(b, require_writable=True)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: from_buffer() takes no keyword arguments

Actual results:
TypeError: from_buffer() takes no keyword arguments

Expected results:
from_buffer(b, require_writable=True) is supported

Additional info:
changelog: https://cffi.readthedocs.io/en/latest/whatsnew.html?highlight=require_writable#v1-12
upstream issue: https://foss.heptapod.net/pypy/cffi/-/issues/394
upstream commit: https://foss.heptapod.net/pypy/cffi/-/commit/c5c4d32c3e3ec0fbaabc4b9890fd17c9c58407d2
Comment 17 Michal Polovka 2023-04-21 12:31:00 UTC 
Preverified using test compose http://artifacts.osci.redhat.com/comp/rhel-8.9.0/52100464-4011-python-cryptography/ with python3-cryptography-3.2.1-6.el8.x86_64  and python3-cffi-1.11.5-6.el8.x86_64     

Python 3.6.8 (default, Jan 23 2023, 22:31:05) 
[GCC 8.5.0 20210514 (Red Hat 8.5.0-18)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from cryptography.hazmat.backends.openssl import backend
>>> b = b'bytes'
>>> buf = backend._ffi.from_buffer(b)
>>> buf[0] = b'a'
>>> b
b'aytes'
>>> buf = backend._ffi.from_buffer(b, require_writable=True)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
BufferError: Object is not writable.
>>> 

parameter require_writable supported, marking as tested.
Comment 21 Michal Polovka 2023-04-24 08:27:13 UTC 
Verified manually using nightly RHEL8.9 machine with python3-cffi-1.11.5-6.el8.x86_64 and python3-cryptography-3.2.1-6.el8.x86_64.


# python3
Python 3.6.8 (default, Jan 23 2023, 22:31:05) 
[GCC 8.5.0 20210514 (Red Hat 8.5.0-18)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from cryptography.hazmat.backends.openssl import backend
>>> b = b'bytes'
>>> buf = backend._ffi.from_buffer(b)
>>> buf[0] = b'a'
>>> b
b'aytes'
>>> buf = backend._ffi.from_buffer(b, require_writable=True)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
BufferError: Object is not writable.

Marking as verified.
Comment 24 errata-xmlrpc 2023-11-14 15:48:23 UTC 
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (python-cffi bug fix and enhancement update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2023:7095
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