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Bug 2128976 - Tools must be hardened to not load "rogue" python modules
Summary: Tools must be hardened to not load "rogue" python modules
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 8
Classification: Red Hat
Component: policycoreutils
Version: 8.6
Hardware: All
OS: Linux
high
high
Target Milestone: rc
: ---
Assignee: Vit Mojzis
QA Contact: Amith
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2022-09-22 07:42 UTC by Renaud Métrich
Modified: 2023-05-16 11:19 UTC (History)
6 users (show)

Fixed In Version: policycoreutils-2.9-21.1.el8
Doc Type: No Doc Update
Doc Text:
Clone Of:
Environment:
Last Closed: 2023-05-16 09:11:23 UTC
Type: Bug
Target Upstream Version:
Embargoed:


Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Issue Tracker RHELPLAN-134657 0 None None None 2022-09-22 07:58:52 UTC
Red Hat Product Errata RHBA-2023:3034 0 None None None 2023-05-16 09:11:28 UTC

Description Renaud Métrich 2022-09-22 07:42:29 UTC
Description of problem:

When a python script is present in "/usr/sbin", it takes precedence over regular modules. This breaks "semanage", for example when a "/usr/sbin/audit.py" script is present, e.g.:
-------- 8< ---------------- 8< ---------------- 8< ---------------- 8< --------
# cat /usr/sbin/audit.py
import sys
print("BAD GUY!", file=sys.stderr)
sys.exit(1)

# semanage boolean -l
BAD GUY!
-------- 8< ---------------- 8< ---------------- 8< ---------------- 8< --------

This is very problematic because it's difficult to troubleshoot: python applications usually read a lot of modules from many places. Finding the culprit requires in-depth analysis using strace or similar tools.

The root cause for this seems to having PYTHONPATH specify "/usr/sbin" when executing "semanage":
-------- 8< ---------------- 8< ---------------- 8< ---------------- 8< --------
# tail /usr/sbin/semanage
[...]

if __name__ == '__main__':
    print(sys.path)
    do_parser()

# semanage boolean -l
['/usr/sbin', '/usr/lib64/python36.zip', '/usr/lib64/python3.6', '/usr/lib64/python3.6/lib-dynload', '/usr/lib64/python3.6/site-packages', '/usr/lib/python3.6/site-packages']
BAD GUY!
-------- 8< ---------------- 8< ---------------- 8< ---------------- 8< --------

The root cause for this is only using "-Es" options in the shebang:
-------- 8< ---------------- 8< ---------------- 8< ---------------- 8< --------
# head -1 /usr/sbin/semanage 
#! /usr/libexec/platform-python -Es
-------- 8< ---------------- 8< ---------------- 8< ---------------- 8< --------

The tools needs to add "-I" as well:
-------- 8< ---------------- 8< ---------------- 8< ---------------- 8< --------
# head -1 /usr/sbin/semanage 
#! /usr/libexec/platform-python -EsI

# semanage boolean -l
['/usr/lib64/python36.zip', '/usr/lib64/python3.6', '/usr/lib64/python3.6/lib-dynload', '/usr/lib64/python3.6/site-packages', '/usr/lib/python3.6/site-packages']
SELinux boolean                State  Default Description
...
-------- 8< ---------------- 8< ---------------- 8< ---------------- 8< --------

Version-Release number of selected component (if applicable):

policycoreutils-python-utils-2.9-19.el8.noarch

How reproducible:

Always

Steps to Reproduce: see above

Comment 10 errata-xmlrpc 2023-05-16 09:11:23 UTC
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (policycoreutils bug fix and enhancement update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2023:3034


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