gh-138008: Fix segfaults in _ctypes due to invalid argtypes #138285

magnified103 · 2025-08-31T08:33:46Z

This PR adds _validate_paramflags checks to the setattr of argtypes, which is likely the best way to fix this issue without performance regressions.

This PR also adds tests for invalid paramflags and argtypes.

Issue: Segfaults in _ctypes during _build_callargs #138008

Signed-off-by: Nguyen Viet Dung <[email protected]>

python-cla-bot · 2025-08-31T08:33:51Z

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bedevere-app · 2025-08-31T08:33:51Z

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Signed-off-by: Nguyen Viet Dung <[email protected]>

bedevere-app · 2025-08-31T08:48:58Z

Most changes to Python require a NEWS entry. Add one using the blurb_it web app or the blurb command-line tool.

If this change has little impact on Python users, wait for a maintainer to apply the skip news label instead.

Misc/NEWS.d/next/Library/2025-08-31-09-06-49.gh-issue-138008.heOvsU.rst

…eOvsU.rst Co-authored-by: Yongzi Li <[email protected]>

Signed-off-by: Nguyen Viet Dung <[email protected]>

encukou

Thank you! I have some suggestions.

Could you also test that with paramflag 2 (“output argument”), the argtype must be a pointer?

Lib/test/test_ctypes/test_prototypes.py

Modules/_ctypes/_ctypes.c

magnified103 · 2025-09-08T11:52:40Z

I have made the requested changes; please review again.

encukou · 2025-09-08T12:33:45Z

Modules/_ctypes/_ctypes.c

        return 0;
    }
-    argtypes = info->argtypes;
+    if (argtypes == NULL || argtypes == Py_None) {


Would it make sense to move the Py_None check to _ctypes_CFuncPtr_argtypes_set_impl? It would be nice to have this closer to the “user”, so the internals only need to consider NULL as special.

I removed the Py_None check since it's already handled by _ctypes_CFuncPtr_argtypes_set_impl. The argtypes parameter will either be NULL or a non-None value.

miss-islington-app · 2025-09-10T12:02:19Z

Thanks @magnified103 for the PR, and @encukou for merging it 🌮🎉.. I'm working now to backport this PR to: 3.13.
🐍🍒⛏🤖

miss-islington-app · 2025-09-10T12:02:19Z

Thanks @magnified103 for the PR, and @encukou for merging it 🌮🎉.. I'm working now to backport this PR to: 3.14.
🐍🍒⛏🤖

miss-islington-app · 2025-09-10T12:02:22Z

Sorry, @magnified103 and @encukou, I could not cleanly backport this to 3.13 due to a conflict.
Please backport using cherry_picker on command line.

cherry_picker 1ce05537a3ebaf1e5c54505b2272d61bb6cf5de0 3.13

encukou · 2025-09-10T12:02:28Z

Thank you for the report and fix!

…thonGH-138285) (cherry picked from commit 1ce0553) Co-authored-by: Dung Nguyen <[email protected]> Signed-off-by: Nguyen Viet Dung <[email protected]> Signed-off-by: Nguyen Viet Dung <[email protected]> Co-authored-by: blurb-it[bot] <43283697+blurb-it[bot]@users.noreply.github.com> Co-authored-by: Yongzi Li <[email protected]>

bedevere-app · 2025-09-10T12:02:37Z

GH-138742 is a backport of this pull request to the 3.14 branch.

bedevere-app · 2025-09-10T12:20:50Z

GH-138745 is a backport of this pull request to the 3.13 branch.

bedevere-app · 2025-09-10T12:21:23Z

GH-138746 is a backport of this pull request to the 3.13 branch.

…pes (pythonGH-138285) (cherry picked from commit 1ce0553) Co-authored-by: Dung Nguyen <[email protected]> Signed-off-by: Nguyen Viet Dung <[email protected]> Signed-off-by: Nguyen Viet Dung <[email protected]> Co-authored-by: blurb-it[bot] <43283697+blurb-it[bot]@users.noreply.github.com> Co-authored-by: Yongzi Li <[email protected]>

…H-138285) (#138746) (cherry picked from commit 1ce0553) Signed-off-by: Nguyen Viet Dung <[email protected]> Signed-off-by: Nguyen Viet Dung <[email protected]> Co-authored-by: Dung Nguyen <[email protected]> Co-authored-by: blurb-it[bot] <43283697+blurb-it[bot]@users.noreply.github.com> Co-authored-by: Yongzi Li <[email protected]>

…H-138285) (GH-138742) (cherry picked from commit 1ce0553) Signed-off-by: Nguyen Viet Dung <[email protected]> Co-authored-by: Yongzi Li <[email protected]> Co-authored-by: Petr Viktorin <[email protected]>

Fix segfaults in _ctypes due to invalid argtypes

0332605

Signed-off-by: Nguyen Viet Dung <[email protected]>

bedevere-app bot added the awaiting review label Aug 31, 2025

bedevere-app bot mentioned this pull request Aug 31, 2025

Segfaults in _ctypes during _build_callargs #138008

Closed

Fix lint

07c9af5

Signed-off-by: Nguyen Viet Dung <[email protected]>

📜🤖 Added by blurb_it.

46037b1

Yzi-Li reviewed Aug 31, 2025

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Misc/NEWS.d/next/Library/2025-08-31-09-06-49.gh-issue-138008.heOvsU.rst Outdated Show resolved Hide resolved

Update Misc/NEWS.d/next/Library/2025-08-31-09-06-49.gh-issue-138008.h…

45f483c

…eOvsU.rst Co-authored-by: Yongzi Li <[email protected]>

magnified103 force-pushed the fix-paramflags branch from b60f833 to 45f483c Compare August 31, 2025 15:14

Merge branch 'main' into fix-paramflags

9c9a65e

Signed-off-by: Nguyen Viet Dung <[email protected]>

magnified103 force-pushed the fix-paramflags branch from 021ee2e to 9c9a65e Compare August 31, 2025 15:16

encukou reviewed Sep 1, 2025

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Lib/test/test_ctypes/test_prototypes.py Outdated Show resolved Hide resolved

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Modules/_ctypes/_ctypes.c Outdated Show resolved Hide resolved

magnified103 added 2 commits September 6, 2025 20:41

Do suggested changes, add more tests

40a1dce

lint fix

41f01a6

Merge branch 'main' into fix-paramflags

adf387f

magnified103 force-pushed the fix-paramflags branch from 16c5fbe to adf387f Compare September 9, 2025 07:13

magnified103 requested a review from encukou September 9, 2025 07:25

encukou reviewed Sep 9, 2025

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Remove the Py_None check in _validate_paramflags

71f5eda

magnified103 requested a review from encukou September 10, 2025 05:44

encukou merged commit 1ce0553 into python:main Sep 10, 2025
81 of 83 checks passed

bedevere-app bot removed the awaiting review label Sep 10, 2025

encukou added needs backport to 3.13 bugs and security fixes needs backport to 3.14 bugs and security fixes labels Sep 10, 2025

miss-islington-app bot assigned encukou Sep 10, 2025

bedevere-app bot removed the needs backport to 3.14 bugs and security fixes label Sep 10, 2025

bedevere-app bot removed the needs backport to 3.13 bugs and security fixes label Sep 10, 2025

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gh-138008: Fix segfaults in _ctypes due to invalid argtypes #138285

gh-138008: Fix segfaults in _ctypes due to invalid argtypes #138285

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