Bug 1579592

Description of problem:
An SELinux messages storm was caused by trying to start rsyslog with the "immark" module enabled:

# auditctl -w /etc/shadow -p w
Error sending add rule data request (Rule exists)

# systemctl start rsyslog && systemctl stop rsyslog
# systemctl status rsyslog | grep -m1 fopen
May 17 17:55:44 horus rsyslogd[28529]: imjournal: fopen() failed for path: '/imjournal.state.tmp': Permission denied [v8.34.0 try http://www.rsyslog.com/e/2013 ]

# ausearch -m avc -ts recent | tail -1
type=AVC msg=audit(1526604944.491:101110): avc:  denied  { dac_override } for  pid=28529 comm="rsyslogd" capability=1  scontext=system_u:system_r:syslogd_t:s0 tcontext=system_u:system_r:syslogd_t:s0 tclass=capability permissive=0

# ausearch -m avc -ts recent | wc -l
147

== Apparently there is a syntax error in /etc/rsyslog.conf:

# dnf download rsyslog
# rpm2cpio < rsyslog*.rpm | cpio -id ./etc/rsyslog.conf

# diff /etc/rsyslog.conf etc/rsyslog.conf 
15c15
< module(load"immark") # provides --MARK-- message capability
---
> #module(load"immark") # provides --MARK-- message capability


=> By simply removing the # from the immark line in the configuration file that is shipped with the package, one introduces a syntax error: it should've read load="immark", with an "=" included. Once this has been fixed, rsyslog starts and the AVC errors are gone too.


While a syntax error may prevent an application not to start or to function properly, it should not cause an AVC message storm. This is a desktop system and with every alert, the SELinux Troubleshooter displays another desktop notification about that alert and the machine got busy pretty quickly trying to display those notifications. That's why I report this agains the selinux package, instead of the application (rsyslog) that triggered this.

SELinux is preventing in:imjournal from using the 'dac_override' capabilities.

*****  Plugin dac_override (91.4 confidence) suggests   **********************

If you want to help identify if domain needs this access or you have a file with the wrong permissions on your system
Then turn on full auditing to get path information about the offending file and generate the error again.
Do

Turn on full auditing
# auditctl -w /etc/shadow -p w
Try to recreate AVC. Then execute
# ausearch -m avc -ts recent
If you see PATH record check ownership/permissions on file, and fix it,
otherwise report as a bugzilla.

*****  Plugin catchall (9.59 confidence) suggests   **************************

If you believe that in:imjournal should have the dac_override capability by default.
Then you should report this as a bug.
You can generate a local policy module to allow this access.
Do
allow this access for now by executing:
# ausearch -c 'in:imjournal' --raw | audit2allow -M my-inimjournal
# semodule -X 300 -i my-inimjournal.pp

Additional Information:
Source Context                system_u:system_r:syslogd_t:s0
Target Context                system_u:system_r:syslogd_t:s0
Target Objects                Unknown [ capability ]
Source                        in:imjournal
Source Path                   in:imjournal
Port                          <Unknown>
Host                          (removed)
Source RPM Packages           
Target RPM Packages           
Policy RPM                    selinux-policy-3.14.1-24.fc28.noarch
Selinux Enabled               True
Policy Type                   targeted
Enforcing Mode                Enforcing
Host Name                     (removed)
Platform                      Linux (removed) 4.16.8-300.fc28.x86_64 #1 SMP Wed
                              May 9 20:23:40 UTC 2018 x86_64 x86_64
Alert Count                   3313
First Seen                    2018-05-17 17:39:51 PDT
Last Seen                     2018-05-17 17:55:44 PDT
Local ID                      9f53de36-0d9a-4404-8c83-3b9465b2cd91

Raw Audit Messages
type=AVC msg=audit(1526604944.491:101110): avc:  denied  { dac_override } for  pid=28529 comm="rsyslogd" capability=1  scontext=system_u:system_r:syslogd_t:s0 tcontext=system_u:system_r:syslogd_t:s0 tclass=capability permissive=0


Hash: in:imjournal,syslogd_t,syslogd_t,capability,dac_override

Version-Release number of selected component:
selinux-policy-3.14.1-24.fc28.noarch

Additional info:
component:      selinux-policy
reporter:       libreport-2.9.5
hashmarkername: setroubleshoot
kernel:         4.16.8-300.fc28.x86_64
type:           libreport