Bug 654504

Summary:	SELinux is preventing /lib/upstart/shutdown "unlink" access on nologin.
Product:	[Fedora] Fedora	Reporter:	John Griffiths <fedora.jrg01>
Component:	selinux-policy	Assignee:	Miroslav Grepl <mgrepl>
Status:	CLOSED ERRATA	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	medium	Docs Contact:
Priority:	low
Version:	14	CC:	dwalsh, mgrepl, plautrba
Target Milestone:	---
Target Release:	---
Hardware:	i386
OS:	Linux
Whiteboard:	setroubleshoot_trace_hash:ef337a65ccc6c5d1100d3fdddb45730b6a43c06341d0ed88a5f9ab8e3e2c94c6
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2010-11-22 09:23:40 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description John Griffiths 2010-11-18 03:23:30 UTC

Summary:

SELinux is preventing /lib/upstart/shutdown "unlink" access on nologin.

Detailed Description:

SELinux denied access requested by shutdown. It is not expected that this access
is required by shutdown and this access may signal an intrusion attempt. It is
also possible that the specific version or configuration of the application is
causing it to require additional access.

Allowing Access:

You can generate a local policy module to allow this access - see FAQ
(http://docs.fedoraproject.org/selinux-faq-fc5/#id2961385) Please file a bug
report.

Additional Information:

Source Context                system_u:system_r:shutdown_t:s0
Target Context                system_u:object_r:etc_runtime_t:s0
Target Objects                nologin [ file ]
Source                        shutdown
Source Path                   /lib/upstart/shutdown
Port                          <Unknown>
Host                          (removed)
Source RPM Packages           upstart-0.6.5-10.fc14
Target RPM Packages           
Policy RPM                    selinux-policy-3.9.7-10.fc14
Selinux Enabled               True
Policy Type                   targeted
Enforcing Mode                Enforcing
Plugin Name                   catchall
Host Name                     (removed)
Platform                      Linux (removed)
                              2.6.35.6-48.fc14.i686.PAE #1 SMP Fri Oct 22
                              15:27:53 UTC 2010 i686 i686
Alert Count                   1
First Seen                    Wed 17 Nov 2010 01:58:17 AM EST
Last Seen                     Wed 17 Nov 2010 01:58:17 AM EST
Local ID                      b686ae6b-36da-4e06-9e86-f23ae0657007
Line Numbers                  

Raw Audit Messages            

node=(removed) type=AVC msg=audit(1289977097.781:50930): avc:  denied  { unlink } for  pid=25106 comm="shutdown" name="nologin" dev=dm-3 ino=3285168 scontext=system_u:system_r:shutdown_t:s0 tcontext=system_u:object_r:etc_runtime_t:s0 tclass=file

node=(removed) type=SYSCALL msg=audit(1289977097.781:50930): arch=40000003 syscall=10 success=no exit=-13 a0=8052c01 a1=0 a2=bffcd30c a3=0 items=0 ppid=25102 pid=25106 auid=4294967295 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=(none) ses=4294967295 comm="shutdown" exe="/lib/upstart/shutdown" subj=system_u:system_r:shutdown_t:s0 key=(null)



Hash String generated from  catchall,shutdown,shutdown_t,etc_runtime_t,file,unlink
audit2allow suggests:

#============= shutdown_t ==============
allow shutdown_t etc_runtime_t:file unlink;

Comment 1 Miroslav Grepl 2010-11-18 09:45:52 UTC

John, 
any idea where is this nologin file located?

# locate -r /nologin$

Comment 2 Miroslav Grepl 2010-11-18 09:49:27 UTC

Petr,
could you look at this bug and also the #652989 bug. Both bugs are related to "nologin" file.

Comment 3 Petr Lautrbach 2010-11-18 10:18:20 UTC

/etc/nologin file is created by /sbin/shutdown -> ../lib/upstart/shutdown during shutdown process. It is used by pam_nologin(8) to avoid new users login into the system.

# shutdown +4 shutdown &
...

wait one minute

# ls -lZ /etc/nologin
-rw-r--r--. root root unconfined_u:object_r:shutdown_etc_t:s0 /etc/nologin

# shutdown -c
shutdown: Shutdown cancelled
[1]+  Done                    shutdown +4 shutdown

# ls -lZ /etc/nologin
ls: cannot access /etc/nologin: No such file or directory

Comment 4 Daniel Walsh 2010-11-18 13:21:41 UTC

I think we are missing a transition here.
Miroslav, we need to add

init_system_domain(shutdown_t, shutdown_exec_t)


I believe what is happening is some init script is executing shutdown, but not transitioning to shutdown_t.  shutdown ends up running as initrc_t and when it creates files in /etc creates them as etc_runtime_t.  If we add the shutdown transition, intirc_t -> shutdown_exec_t -> shutdown_t

And when shutdown_t creates files in etc_t it will create them as shutdown_etc_t which will work.

Comment 5 Miroslav Grepl 2010-11-18 14:22:30 UTC

Sounds reasonably.

Comment 6 Miroslav Grepl 2010-11-22 09:23:40 UTC

It was fixed in selinux-policy-3.9.7-12.fc14