Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

ctypes: Crash if manually-created CField instance is used #78878

Closed
izbyshev mannequin opened this issue Sep 15, 2018 · 4 comments
Closed

ctypes: Crash if manually-created CField instance is used #78878

izbyshev mannequin opened this issue Sep 15, 2018 · 4 comments
Labels
3.9 3.10 3.11 expert-ctypes type-crash A hard crash of the interpreter, possibly with a core dump

Comments

@izbyshev
Copy link
Mannequin

izbyshev mannequin commented Sep 15, 2018 •
edited by bedevere-bot

BPO 34697
Nosy @amauryfa, @abalkin, @meadori, @berkerpeksag, @serhiy-storchaka, @izbyshev, @tirkarthi, @shihai1991
PRs
  • gh-78878: Fix crash when creating an instance of _ctypes.CField #14837
    		•

    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 = 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'

    bugs.python.org fields:

    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']

    Linked PRs
    @izbyshev
    Copy link
    Mannequin Author

    izbyshev mannequin commented Sep 15, 2018

    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?

    @izbyshev izbyshev mannequin added 3.7 3.8 expert-ctypes type-crash A hard crash of the interpreter, possibly with a core dump labels Sep 15, 2018
    @serhiy-storchaka
    Copy link
    Member

    serhiy-storchaka commented Jul 13, 2019

    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?

    @shihai1991
    Copy link
    Member

    shihai1991 commented Jul 18, 2019

    I have try to cancel this PyCField_new function, but i am not sure I haven't break the code structure.

    @shihai1991
    Copy link
    Member

    shihai1991 commented Aug 3, 2019

    ping

    @ezio-melotti ezio-melotti transferred this issue from another repository Apr 10, 2022
    @bedevere-bot bedevere-bot mentioned this issue Dec 18, 2022
    Merged
    kumaraditya303 pushed a commit that referenced this issue Dec 21, 2022
    @shihai1991
    gh-78878: Fix crash when creating an instance of _ctypes.CField (#1…
    d713c54 
    …4837)
    @bedevere-bot bedevere-bot mentioned this issue Dec 21, 2022
    Merged
    miss-islington pushed a commit to miss-islington/cpython that referenced this issue Dec 21, 2022
    @shihai1991 @miss-islington
    pythongh-78878: Fix crash when creating an instance of `_ctypes.CFiel…
    8b8519a 
    …d` (pythonGH-14837)

(cherry picked from commit d713c54)

Co-authored-by: Hai Shi <shihai1992@gmail.com>
    miss-islington added a commit that referenced this issue Dec 21, 2022
    @miss-islington @shihai1991
    gh-78878: Fix crash when creating an instance of _ctypes.CField (GH…
    3e715e0 
    …-14837)

(cherry picked from commit d713c54)

Co-authored-by: Hai Shi <shihai1992@gmail.com>
    Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
    Assignees
    No one assigned
    Labels
    3.9 3.10 3.11 expert-ctypes type-crash A hard crash of the interpreter, possibly with a core dump
    Projects
    None yet
    Milestone
    No milestone
    Development

    No branches or pull requests
    4 participants
    @iritkatriel @serhiy-storchaka @shihai1991 @kumaraditya303