os.makedirs() not thread-safe¶
os.makedirs(exist_ok=True) is not thread-safe: umask is set temporary
to 0, serious security problem.
The fix removes the directory mode check from os.makedirs().
The exist_ok parameter was added to Python 3.2.0 (commit
5a22b651173f142a600625a036fcf36484ade237).
- Disclosure date: 2014-03-28 (Python issue bpo-21082 reported)
Fixed In¶
- Python 3.2.6 (2014-10-11) fixed by commit ee5f1c1 (branch 3.2) (2014-04-01)
- Python 3.3.6 (2014-10-11) fixed by commit ee5f1c1 (branch 3.2) (2014-04-01)
- Python 3.4.1 (2014-05-18) fixed by commit ee5f1c1 (branch 3.2) (2014-04-01)
- Python 3.5.0 (2015-09-09) fixed by commit ee5f1c1 (branch 3.2) (2014-04-01)
Python issue¶
os.makedirs(exist_ok=True) is not thread-safe: umask is set temporary to 0, serious security problem.
- Python issue: bpo-21082
- Creation date: 2014-03-28
- Reporter: Ryan Lortie
CVE-2014-2667¶
Race condition in the _get_masked_mode function in Lib/os.py in Python 3.2 through 3.5, when exist_ok is set to true and multiple threads are used, might allow local users to bypass intended file permissions by leveraging a separate application vulnerability before the umask has been set to the expected value.
- CVE ID: CVE-2014-2667
- Published: 2014-11-15
- CVSS Score: 3.3
Timeline¶
Timeline using the disclosure date 2014-03-28 as reference:
- 2014-03-28: Python issue bpo-21082 reported by Ryan Lortie
- 2014-04-01 (+4 days): commit ee5f1c1 (branch 3.2)
- 2014-05-18 (+51 days): Python 3.4.1 released
- 2014-10-11 (+197 days): Python 3.2.6 released
- 2014-10-11 (+197 days): Python 3.3.6 released
- 2014-11-15 (+232 days): CVE-2014-2667 published
- 2015-09-09: Python 3.5.0 released