Bug 1883906
| Summary: | selinux prevents timedatex (timedatectl) commands running from cron on RHEL8.x | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux 8 | Reporter: | Eize Speerstra <eize.speerstra> |
| Component: | selinux-policy | Assignee: | Zdenek Pytela <zpytela> |
| Status: | CLOSED ERRATA | QA Contact: | Milos Malik <mmalik> |
| Severity: | medium | Docs Contact: | |
| Priority: | medium | ||
| Version: | --- | CC: | jangerrit.kootstra, lvrabec, mmalik, plautrba, ssekidde |
| Target Milestone: | rc | Keywords: | Triaged |
| Target Release: | 8.4 | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | No Doc Update | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2021-05-18 14:58:17 UTC | Type: | Bug |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
Reproducible on RHEL-8.3 too:
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type=USER_AVC msg=audit(10/01/2020 10:23:01.668:335) : pid=1158 uid=dbus auid=unset ses=unset subj=system_u:system_r:system_dbusd_t:s0-s0:c0.c1023 msg='avc: denied { send_msg } for msgtype=method_return dest=:1.213 spid=7160 tpid=7159 scontext=system_u:system_r:timedatex_t:s0 tcontext=system_u:system_r:system_cronjob_t:s0-s0:c0.c1023 tclass=dbus permissive=0 exe=/usr/bin/dbus-daemon sauid=dbus hostname=? addr=? terminal=?'
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# rpm -qa selinux\*
selinux-policy-devel-3.14.3-54.el8.noarch
selinux-policy-3.14.3-54.el8.noarch
selinux-policy-doc-3.14.3-54.el8.noarch
selinux-policy-minimum-3.14.3-54.el8.noarch
selinux-policy-sandbox-3.14.3-54.el8.noarch
selinux-policy-mls-3.14.3-54.el8.noarch
selinux-policy-targeted-3.14.3-54.el8.noarch
# grep -v '#' /etc/crontab
SHELL=/bin/bash
PATH=/sbin:/bin:/usr/sbin:/usr/bin
MAILTO=root
* * * * * root timedatectl set-timezone Europe/Prague
#
The only SELinux denial which appeared in permissive mode is:
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type=USER_AVC msg=audit(10/01/2020 10:27:01.641:394) : pid=1158 uid=dbus auid=unset ses=unset subj=system_u:system_r:system_dbusd_t:s0-s0:c0.c1023 msg='avc: denied { send_msg } for msgtype=method_return dest=:1.245 spid=8554 tpid=8553 scontext=system_u:system_r:timedatex_t:s0 tcontext=system_u:system_r:system_cronjob_t:s0-s0:c0.c1023 tclass=dbus permissive=1 exe=/usr/bin/dbus-daemon sauid=dbus hostname=? addr=? terminal=?'
----
# sesearch -s timedatex_t -t system_cronjob_t -c dbus -A
# sesearch -s system_cronjob_t -t timedatex_t -c dbus -A
allow dbusd_unconfined timedatex_t:dbus send_msg;
#
Does the scenario work for normal or confined users? The scenario executed under normal confined users does not produce any SELinux denials. Unfortunately, it fails to change the timezone - Not authorized. I've submitted a Fedora PR to address the issue: https://github.com/fedora-selinux/selinux-policy/pull/502 This is the rawhide commit:
commit 4d2207194e25b20e9b2c52de49f4d550c1488ab3 (HEAD -> rawhide, upstream/rawhide)
Author: Zdenek Pytela <zpytela>
Date: Tue Dec 8 22:49:21 2020 +0100
Allow timedatex dbus chat with cron system domain
Resolves: rhbz#1883906
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 (selinux-policy 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-2021:1639 |
Description of problem: When running timedatectl via cron I get a timeout. This happens on RHEL/CentOS 8 only. (tested on RHEL8.1, CentOS 8.1, RHEL8.2 and CentOS8.2) timedatex send a message to dbus, but is denied access by selinux. audit logging: type=USER_AVC msg=audit(1600182869.302:16052): pid=1045 uid=81 auid=4294967295 ses=4294967295 subj=system_u:system_r:system_dbusd_t:s0-s0:c0.c1023 msg='avc: denied { send_msg } for msgtype=method_return dest=:1.11257 spid=1128745 tpid=1128751 scontext=system_u:system_r:timedatex_t:s0 tcontext=system_u:system_r:system_cronjob_t:s0-s0:c0.c1023 tclass=dbus permissive=0 exe="/usr/bin/dbus-daemon" sauid=81 hostname=? addr=? terminal=?' audit2why: Was caused by: Missing type enforcement (TE) allow rule. I have created a local policy as a workaround, but I believe this should be in the generic policy Version-Release number of selected component (if applicable): 0.5-3.el8 How reproducible: Always Steps to Reproduce: 1. create a shell script with timedatectl set-timezone Europe/Amsterdam 2. create cron-job for it 3. wait for it to be executed by cron Actual results: Failed to set time zone: Connection timed out Expected results: time zone set without error Additional info: