Bug 2218233 - ansible-core: Python tarfile extraction needs change to avoid a warning (CVE-2007-4559 mitigation)
Summary: ansible-core: Python tarfile extraction needs change to avoid a warning (CVE-...
Keywords:
Status: NEW
Alias: None
Product: Red Hat Enterprise Linux 8
Classification: Red Hat
Component: ansible-core
Version: 8.9
Hardware: Unspecified
OS: Unspecified
unspecified
unspecified
Target Milestone: rc
: ---
Assignee: Dimitri Savineau
QA Contact: Matt Clay
URL:
Whiteboard:
Depends On: CVE-2007-4559
Blocks:
TreeView+ depends on / blocked
 
Reported: 2023-06-28 13:57 UTC by Charalampos Stratakis
Modified: 2023-06-30 11:31 UTC (History)
4 users (show)

Fixed In Version:
Doc Type: If docs needed, set a value
Doc Text:
Clone Of: 2203890
Environment:
Last Closed:
Type: Bug
Target Upstream Version:
Embargoed:


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System ID Private Priority Status Summary Last Updated
Red Hat Issue Tracker RHELPLAN-161092 0 None None None 2023-06-28 14:00:16 UTC

Description Charalampos Stratakis 2023-06-28 13:57:37 UTC
+++ This bug was initially created as a clone of Bug #2203890 +++

Hello,
In RHEL 9.3 and 8.9, we're planning to fix the long-standing CVE-2007-4559: Python's `tarfile` module makes it too easy to extract tarballs in an unsafe way.
Unfortunately, for the CVE to be considered fixed, this needs a behavior change. (If you don't think this is the case, let's bring it up with the security team.)
Upstream, Python will emit deprecation warnings for 2 releases, but in RHEL we change the behavior now, emit warnings, and provide ways for customers to restore earlier behavior.
To avoid the warning, software shipped by Red Hat will need a change.

For more details see upstream PEP 706: https://peps.python.org/pep-0706
and the Red Hat knowledge base draft: https://access.redhat.com/articles/7004769

---

In /usr/lib/python3.11/site-packages/ansible/galaxy/role.py, ansible-core calls `role_tar_file.extract()`. The call will emit a warning by default, and should be changed to something like:

if hasattr(tarfile, 'data_filter'):
    # Python with CVE-2007-4559 mitigation (PEP 706)
    role_tar_file.extract(..., filter='data')
else:
    # Fallback to a possibly dangerous extraction (before PEP 706)
    role_tar_file.extract(...)

The 'data' filter above attempts a "safe" extraction, intended for pure data archives. For example:
- prevents extracting outside the target directory, and to absolute paths (by raising an exception)
- prevents symlinks pointing outside the target directory, and to absolute paths
- adjusts permissions (for the owner, only the executable bit is honored)
See PEP 706 for details: https://peps.python.org/pep-0706/#filters

If you trust your validation, use `filter='fully_trusted'` instead. That will preserve the existing behavior.
(I don't know if you are concerned about *this* tarball being malicious. At first glance, your validation won't prevent malicious tarballs from extracting outside `self.path`. Happy to elaborate.)

---

Let me know if you have any questions!

Comment 1 Petr Viktorin 2023-06-30 11:31:46 UTC
On RHEL8, the ansible-test subpackage calls `extractall` in /usr/lib/python3.11/site-packages/ansible_test/_internal/commands/sanity/validate_modules.py
This call needs to be adjusted in the same way.


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