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Created on 2015-05-21 08:40 by serhiy.storchaka, last changed 2022-04-11 14:58 by admin. This issue is now closed.
| Files | ||||
|---|---|---|---|---|
| File name | Uploaded | Description | Edit | |
| typecheck.patch | serhiy.storchaka, 2015-05-21 08:40 | review | ||
| typecheck_2.patch | serhiy.storchaka, 2015-05-21 15:25 | review | ||
| Messages (6) | |||
|---|---|---|---|
| msg243739 - (view) | Author: Serhiy Storchaka (serhiy.storchaka) *  |
Date: 2015-05-21 08:40 | |
PyObject_IsInstance() is used incorrectly for testing if Python object is an instance of specified builtin type before direct access to internals of object. This is not correct, because PyObject_IsInstance() checks the __class__ attribute that can be modified and even can be dynamic property. Correct way is to check static type. Proposed patch replaces PyObject_IsInstance() with PyObject_TypeCheck() if this is appropriate. See also similar issues issue24102 and issue24091. |
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| msg243752 - (view) | Author: R. David Murray (r.david.murray) * |
Date: 2015-05-21 14:02 | |
Is there any chance that these changes will break working code, or is it the case that if the current check passes incorrectly one will always get a segfauilt or other error? |
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| msg243754 - (view) | Author: Raymond Hettinger (rhettinger) * |
Date: 2015-05-21 14:57 | |
> is it the case that if the current check passes incorrectly > one will always get a segfauilt or other error? Yes, that is the case. All four of these checks precede a reference to an structure member that depends on being an exact type or subtype. So, yes they are all necessary to prevent segfaults or other undefined behavior. |
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| msg243756 - (view) | Author: Serhiy Storchaka (serhiy.storchaka) * |
Date: 2015-05-21 15:25 | |
Yes, it is the case that if the current check passes incorrectly one will always get a segfauilt or other error. Added tests for types.SimpleNamespace and sqlite3.Cursor. It is not easy to reproduce a bug for StopIterator (not sure it is reproducible), but the code looks definitely erroneous in any case. |
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| msg243797 - (view) | Author: Raymond Hettinger (rhettinger) * |
Date: 2015-05-22 01:15 | |
Serhiy, go ahead and apply your patch. The existing code is clearly wrong. |
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| msg243820 - (view) | Author: Roundup Robot (python-dev)  |
Date: 2015-05-22 08:14 | |
New changeset bccaba8a5482 by Serhiy Storchaka in branch '2.7': Issue #24257: Fixed segmentation fault in sqlite3.Row constructor with faked https://hg.python.org/cpython/rev/bccaba8a5482 New changeset c7b9645a6f35 by Serhiy Storchaka in branch '3.4': Issue #24257: Fixed incorrect uses of PyObject_IsInstance(). https://hg.python.org/cpython/rev/c7b9645a6f35 New changeset a5101529a8a9 by Serhiy Storchaka in branch 'default': Issue #24257: Fixed incorrect uses of PyObject_IsInstance(). https://hg.python.org/cpython/rev/a5101529a8a9 |
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| History | |||
|---|---|---|---|
| Date | User | Action | Args |
| 2022-04-11 14:58:17 | admin | set | github: 68445 |
| 2015-05-22 08:24:25 | serhiy.storchaka | set | status: open -> closed resolution: fixed stage: patch review -> resolved |
| 2015-05-22 08:14:05 | python-dev | set | nosy:
+ python-dev messages: + msg243820 |
| 2015-05-22 01:15:15 | rhettinger | set | assignee: serhiy.storchaka messages: + msg243797 |
| 2015-05-21 15:25:23 | serhiy.storchaka | set | files:
+ typecheck_2.patch messages: + msg243756 |
| 2015-05-21 14:57:22 | rhettinger | set | nosy:
+ rhettinger messages: + msg243754 |
| 2015-05-21 14:02:04 | r.david.murray | set | nosy:
+ r.david.murray messages: + msg243752 |
| 2015-05-21 08:40:46 | serhiy.storchaka | create | |