Description

assignee = None
closed_at = None
created_at = <Date 2018-09-15.17:13:13.204>
labels = ['3.10', 'ctypes', '3.9', 'type-crash', '3.11']
title = 'ctypes: Crash if manually-created CField instance is used'
updated_at = <Date 2022-01-23.19:52:13.578>
user = 'https://github.com/izbyshev'

activity = <Date 2022-01-23.19:52:13.578>
actor = 'iritkatriel'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['ctypes']
creation = <Date 2018-09-15.17:13:13.204>
creator = 'izbyshev'
dependencies = []
files = []
hgrepos = []
issue_num = 34697
keywords = ['patch']
message_count = 4.0
messages = ['325448', '347814', '348113', '348944']
nosy_count = 8.0
nosy_names = ['amaury.forgeotdarc', 'belopolsky', 'meador.inge', 'berker.peksag', 'serhiy.storchaka', 'izbyshev', 'xtreak', 'shihai1991']
pr_nums = ['14837']
priority = 'normal'
resolution = None
stage = 'patch review'
status = 'open'
superseder = None
type = 'crash'
url = 'https://bugs.python.org/issue34697'
versions = ['Python 3.9', 'Python 3.10', 'Python 3.11']

Activity

1. izbyshev commented on Sep 15, 2018

   

   izbyshevmannequin

   on Sep 15, 2018

   MannequinAuthor

   More actions

   It is possible to manually create an instance of private CField type which is used by ctypes to represent fields of Structure and Union types. This instance will be uninitialized because it's normally initialized when instances of Structure/Union are created, so calling its methods may crash the interpreter:

   from ctypes import *
   
   class S(Structure):
       _fields_ = [('x', c_int)]
   
   CField = type(S.x)
   f = CField()
   repr(f) # Crash here

   Is this issue worth fixing?

   If so, is the correct way to set tp_new slot to NULL and fix the internal callers so that users wouldn't be able to create CField instances?
2. izbyshev

   added

   3.7 (EOL)end of lifeend of life

   3.8 (EOL)end of lifeend of life

   topic-ctypes

   type-crashA hard crash of the interpreter, possibly with a core dumpA hard crash of the interpreter, possibly with a core dump

   on Sep 15, 2018
3. serhiy-storchaka commented on Jul 13, 2019

   

   serhiy-storchaka

   on Jul 13, 2019

   Member

   More actions

   Is this issue worth fixing?

   Definitely yes.

   If so, is the correct way to set tp_new slot to NULL and fix the internal callers so that users wouldn't be able to create CField instances?

   I think yes.

   Do you mind to create a PR?
4. shihai1991 commented on Jul 18, 2019

   

   shihai1991

   on Jul 18, 2019

   Member

   More actions

   I have try to cancel this PyCField_new function, but i am not sure I haven't break the code structure.
5. shihai1991 commented on Aug 3, 2019

   

   shihai1991

   on Aug 3, 2019

   Member

   More actions

   ping
6. iritkatriel

   added

   3.9 (EOL)end of lifeend of life

   3.10 (EOL)end of lifeend of life

   3.11only security fixesonly security fixes

   and removed

   3.7 (EOL)end of lifeend of life

   3.8 (EOL)end of lifeend of life

   on Jan 23, 2022
7. ezio-melotti

   transferred this issue fromon Apr 10, 2022
8. kumaraditya303

   added a commit that references this issue on Dec 21, 2022

   gh-78878: Fix crash when creating an instance of `_ctypes.CField` (#1…

   d713c54
9. miss-islington

   added 2 commits that reference this issue on Dec 21, 2022

   pythongh-78878: Fix crash when creating an instance of `_ctypes.CFiel…

   8b8519a

   gh-78878: Fix crash when creating an instance of `_ctypes.CField` (GH…

   3e715e0
10. kumaraditya303

    closed this as completedon Dec 21, 2022
11. iritkatriel

    added a commit that references this issue on Dec 28, 2022

    Merged main into regmachine branch (#50)

    fdc73cb

Issue actions