Bug 718629

Summary: SELinux is preventing /usr/sbin/sshd from read, write access on the file .pam-systemd-lock.
Product: [Fedora] Fedora Reporter: John Griffiths <fedora.jrg01>
Component: selinux-policyAssignee: Miroslav Grepl <mgrepl>
Status: CLOSED CURRENTRELEASE QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: medium Docs Contact:
Priority: unspecified    
Version: 15CC: dominick.grift, dwalsh, harald, johannbg, lpoetter, metherid, mgrepl, mschmidt, notting, plautrba
Target Milestone: ---   
Target Release: ---   
Hardware: i386   
OS: Linux   
Whiteboard: setroubleshoot_trace_hash:2e297d8442d5c6f9eb96dda7b9219c64fa7a176372eea452f1a09003986a879b
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2011-10-07 14:31:34 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:

Description John Griffiths 2011-07-04 04:45:39 UTC
SELinux is preventing /usr/sbin/sshd from read, write access on the file .pam-systemd-lock.

*****  Plugin catchall (100. confidence) suggests  ***************************

If you believe that sshd should be allowed read write access on the .pam-systemd-lock file 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:
# grep sshd /var/log/audit/audit.log | audit2allow -M mypol
# semodule -i mypol.pp

Additional Information:
Source Context                system_u:system_r:sshd_t:s0-s0:c0.c1023
Target Context                system_u:object_r:crond_var_run_t:s0
Target Objects                .pam-systemd-lock [ file ]
Source                        sshd
Source Path                   /usr/sbin/sshd
Port                          <Unknown>
Host                          (removed)
Source RPM Packages           openssh-server-5.6p1-31.fc15.1
Target RPM Packages           
Policy RPM                    selinux-policy-3.9.16-30.fc15
Selinux Enabled               True
Policy Type                   targeted
Enforcing Mode                Enforcing
Host Name                     (removed)
Platform                      Linux (removed)
                              2.6.38.8-32.fc15.i686.PAE #1 SMP Mon Jun 13
                              19:55:27 UTC 2011 i686 i686
Alert Count                   10
First Seen                    Tue 28 Jun 2011 01:26:01 PM EDT
Last Seen                     Thu 30 Jun 2011 01:37:07 PM EDT
Local ID                      886e56a4-abeb-475e-911f-fbc67155a1d7

Raw Audit Messages
type=AVC msg=audit(1309455427.119:36794): avc:  denied  { read write } for  pid=27705 comm="sshd" name=".pam-systemd-lock" dev=tmpfs ino=22223 scontext=system_u:system_r:sshd_t:s0-s0:c0.c1023 tcontext=system_u:object_r:crond_var_run_t:s0 tclass=file


type=SYSCALL msg=audit(1309455427.119:36794): arch=i386 syscall=open success=no exit=EACCES a0=72bea4 a1=a8142 a2=180 a3=21c9e648 items=0 ppid=1631 pid=27705 auid=500 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=100 fsgid=0 tty=(none) ses=5114 comm=sshd exe=/usr/sbin/sshd subj=system_u:system_r:sshd_t:s0-s0:c0.c1023 key=(null)

Hash: sshd,sshd_t,crond_var_run_t,file,read,write

audit2allow

#============= sshd_t ==============
allow sshd_t crond_var_run_t:file { read write };

audit2allow -R

#============= sshd_t ==============
allow sshd_t crond_var_run_t:file { read write };

Comment 1 Daniel Walsh 2011-07-05 17:32:08 UTC
systemd guys what is the .pam-systemd-lock file?

Comment 2 Daniel Walsh 2011-07-05 17:33:32 UTC
John where is this file located?

Comment 3 John Griffiths 2011-07-05 19:01:33 UTC
Dan, It is in /run/user/

/run/user/.pam-systemd-lock

Comment 4 Daniel Walsh 2011-07-05 19:26:31 UTC
John you had a similar bug with lots of mislabeled files, did relabeling your system fix the problems?

Comment 5 John Griffiths 2011-07-05 20:15:13 UTC
When I found this problem, I ran restorecon -Rvn /run as a matter of inquisitiveness and found many badly labeled files, so I filed Bug 718631.

Relabeling did not fix the bad labels.

Since /run is a tmpfs file system, /run is recreated at boot. That would indicate to me that there are a lot of packages creating with the wrong contexts or the policy expects the wrong contexts.

Comment 6 Lennart Poettering 2011-07-06 21:56:53 UTC
(In reply to comment #1)
> systemd guys what is the .pam-systemd-lock file?

It's a lock file /run/user/.pam-systemd-lock we use in pam_systemd to serialize access to the cgroup, so that we can safely decide when a user's cgroup can be killed. All programs that provide a PAM service and thus end up loading pam_systemd will have to access this file.

Comment 7 Daniel Walsh 2011-07-07 12:58:41 UTC
We have found john's problem being an empty /etc/selinux/targeted/files/file_contexts.subs file.  We have not figured out how this got cleared.


I am suspecting some semanage command executed in the post install of an rpm is causing this.

John can you see if someone is playing with equivalence in post install.

# rpm -qa --scripts > /tmp/scripts
# grep -- semanage.*-e /tmp/scripts

Comment 8 John Griffiths 2011-07-07 13:08:38 UTC
# rpm -qa --scripts > /tmp/scripts
# grep -- semanage.*-e /tmp/scripts

yields nothing.

Comment 9 Daniel Walsh 2011-07-07 17:14:01 UTC
Strange, Did you install from a live image?

Comment 10 John Griffiths 2011-07-07 17:31:33 UTC
No. Installed from DVD image. I got it from the torrent.

Comment 11 Daniel Walsh 2011-07-07 18:07:36 UTC
I have no clue what is going on then.

You are the only one I have heard about this from.  But you have seen it on multiple machines.

Comment 12 John Griffiths 2011-07-07 18:37:09 UTC
Well the labels were right, only restorecon thought they were wrong, so I guess everything (almost) was working correctly so who would notice?

The AVC for the sshd did not prevent ssh from working. I just got tired of seeing it in sealert, so I reported the bug. I was surprised that I was the first.

I only noticed the problem with /run when out of curiosity, I ran restorecon -Rvn against it. Otherwise, I would have never known about this either.

I guess what I am saying is it may be prevalent with many (most) systems but is going un-noticed.

Comment 13 Miroslav Grepl 2011-07-11 12:46:28 UTC
Let's clean up this issue. 

Is your /etc/selinux/targeted/files/file_contexts.subs file still empty?

Comment 14 John Griffiths 2011-07-11 13:51:41 UTC
After deleting file and reinstalling the policy the correct file_contexts.subs was installed. 

I have no idea how the empty file got installed. It happened on two FC15 servers both with fresh installs from the DVD iso gotten from the torrent.