Bug 229466 - SELinux prevents automatic addition of machine accounts in a Samba PDC
Summary: SELinux prevents automatic addition of machine accounts in a Samba PDC
Status: CLOSED ERRATA
Alias: None
Product: Fedora
Classification: Fedora
Component: selinux-policy-targeted
Version: 6
Hardware: All
OS: Linux
medium
high
Target Milestone: ---
Assignee: Daniel Walsh
QA Contact: Ben Levenson
URL:
Whiteboard:
Keywords:
Depends On:
Blocks: 235360
TreeView+ depends on / blocked
 
Reported: 2007-02-21 12:04 UTC by Markku Kolkka
Modified: 2007-11-30 22:11 UTC (History)
0 users

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Clone Of:
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Last Closed: 2007-05-29 10:04:55 UTC


Attachments (Terms of Use)
Try this policy package. (97 bytes, application/octet-stream)
2007-02-22 16:53 UTC, Daniel Walsh
no flags Details

Description Markku Kolkka 2007-02-21 12:04:37 UTC
Description of problem:
The Fedora machine is set up as a Samba PDC, but trying to join a Windows
machine in the domain fails if SELinux is in enforcing mode, the samba log shows
that machine account creation failed. In permissive mode joining succeeds, but
with a large number of SELinux alerts.

Version-Release number of selected component (if applicable):
selinux-policy-targeted-2.4.6-40.fc6

How reproducible:
always

Steps to Reproduce:
1. Setup Samba as a primary domain controller
2. Log in a Windows machine and try to join the domain created in step 1.
  
Actual results:
The machine account isn't created and joining fails.

Expected results:
The Windows macine is added to the domain and a machine account created.

Additional info:
The error in smb.log when trying to add a machine "opetus5" to the domain with
SELinux in enforcing mode:
[2007/02/21 13:31:43, 0] passdb/pdb_interface.c:pdb_default_create_user(368)
  _samr_create_user: Running the command `/usr/sbin/adduser -n -g machines -c Ma
chine -d /dev/null -s /bin/false opetus5$' gave 82

Comment 1 Daniel Walsh 2007-02-21 15:47:07 UTC
Please grab the avc messages from /var/log/audit/audit.log or /var/log/messages.

Comment 2 Markku Kolkka 2007-02-22 08:31:29 UTC
The message while in enforcing mode:
avc: denied { search } for comm="smbd" dev=dm-0 egid=0 euid=0 
exe="/usr/sbin/smbd" exit=-13 fsgid=0 fsuid=0 gid=0 items=0 name="bin" 
pid=2748 scontext=system_u:system_r:smbd_t:s0 sgid=0 
subj=system_u:system_r:smbd_t:s0 suid=0 tclass=dir 
tcontext=system_u:object_r:bin_t:s0 tty=(none) uid=0 

In permissive mode:
avc: denied { lock } for comm="adduser" dev=dm-0 egid=0 euid=0 
exe="/usr/sbin/useradd" exit=0 fsgid=0 fsuid=0 gid=0 items=0 name=".pwd.lock" 
path="/etc/.pwd.lock" pid=2926 scontext=system_u:system_r:smbd_t:s0 sgid=0 
subj=system_u:system_r:smbd_t:s0 suid=0 tclass=file 
tcontext=system_u:object_r:shadow_t:s0 tty=(none) uid=0 

avc: denied { write } for comm="adduser" dev=dm-0 egid=0 euid=0 
exe="/usr/sbin/useradd" exit=5 fsgid=0 fsuid=0 gid=0 items=0 
name="passwd.2926" path="/etc/passwd.2926" pid=2926 
scontext=system_u:system_r:smbd_t:s0 sgid=0 subj=system_u:system_r:smbd_t:s0 
suid=0 tclass=file tcontext=system_u:object_r:etc_t:s0 tty=(none) uid=0

avc: denied { read } for comm="adduser" dev=dm-2 egid=0 euid=0 
exe="/usr/sbin/useradd" exit=0 fsgid=0 fsuid=0 gid=0 items=0 name="useradd" 
path="/usr/sbin/useradd" pid=2926 scontext=system_u:system_r:smbd_t:s0 sgid=0 
subj=system_u:system_r:smbd_t:s0 suid=0 tclass=file 
tcontext=system_u:object_r:useradd_exec_t:s0 tty=(none) uid=0 

avc: denied { create } for comm="adduser" dev=dm-0 egid=0 euid=0 
exe="/usr/sbin/useradd" exit=6 fsgid=0 fsuid=0 gid=0 items=0 
name="passwd.2926" pid=2926 scontext=system_u:system_r:smbd_t:s0 sgid=0 
subj=system_u:system_r:smbd_t:s0 suid=0 tclass=file 
tcontext=system_u:object_r:etc_t:s0 tty=(none) uid=0

avc: denied { read, write } for comm="adduser" dev=dm-3 egid=0 euid=0 
exe="/usr/sbin/useradd" exit=10 fsgid=0 fsuid=0 gid=0 items=0 name="faillog" 
pid=2926 scontext=system_u:system_r:smbd_t:s0 sgid=0 
subj=system_u:system_r:smbd_t:s0 suid=0 tclass=file 
tcontext=system_u:object_r:faillog_t:s0 tty=(none) uid=0

avc: denied { read, write } for comm="adduser" dev=dm-3 egid=0 euid=0 
exe="/usr/sbin/useradd" exit=10 fsgid=0 fsuid=0 gid=0 items=0 name="lastlog" 
pid=2926 scontext=system_u:system_r:smbd_t:s0 sgid=0 
subj=system_u:system_r:smbd_t:s0 suid=0 tclass=file 
tcontext=system_u:object_r:lastlog_t:s0 tty=(none) uid=0 

avc: denied { unlink } for comm="adduser" dev=dm-0 egid=0 euid=0 
exe="/usr/sbin/useradd" exit=0 fsgid=0 fsuid=0 gid=0 items=0 name="passwd" 
pid=2926 scontext=system_u:system_r:smbd_t:s0 sgid=0 
subj=system_u:system_r:smbd_t:s0 suid=0 tclass=file 
tcontext=user_u:object_r:etc_t:s0 tty=(none) uid=0 

avc: denied { setattr } for comm="adduser" dev=dm-0 egid=0 euid=0 
exe="/usr/sbin/useradd" exit=0 fsgid=0 fsuid=0 gid=0 items=0 name="passwd-" 
pid=2926 scontext=system_u:system_r:smbd_t:s0 sgid=0 
subj=system_u:system_r:smbd_t:s0 suid=0 tclass=file 
tcontext=system_u:object_r:etc_t:s0 tty=(none) uid=0 

avc: denied { create } for comm="adduser" egid=0 euid=0 
exe="/usr/sbin/useradd" exit=6 fsgid=0 fsuid=0 gid=0 items=0 name="passwd+" 
pid=2926 scontext=system_u:system_r:smbd_t:s0 sgid=0 
subj=system_u:system_r:smbd_t:s0 suid=0 tclass=file 
tcontext=user_u:object_r:etc_t:s0 tty=(none) uid=0 

avc: denied { setattr } for comm="adduser" dev=dm-0 egid=0 euid=0 
exe="/usr/sbin/useradd" exit=0 fsgid=0 fsuid=0 gid=0 items=0 name="passwd+" 
pid=2926 scontext=system_u:system_r:smbd_t:s0 sgid=0 
subj=system_u:system_r:smbd_t:s0 suid=0 tclass=file 
tcontext=user_u:object_r:etc_t:s0 tty=(none) uid=0 


Comment 3 Daniel Walsh 2007-02-22 16:53:02 UTC
Created attachment 148597 [details]
Try this policy package.

Save this attachment to a directory my itself and name it mysamba.te
Install selinux-policy-devel
# yum -y install selinux-policy-devel
# make -f /usr/share/selinux/devel/Makefile
# semodule -i mysamba.pp

Now try samba in enforcing mode and see if it works.	I will update fc6 with
this policy if it does.

Comment 4 Markku Kolkka 2007-02-23 10:43:42 UTC
After installing the above policy package joining the domain works, but with a 
SELinux message: SELinux is preventing /usr/sbin/useradd (useradd_t) "append" 
to /var/log/samba/smbd.log (samba_log_t).

avc: denied { append } for comm="adduser" dev=dm-3 egid=0 euid=0 
exe="/usr/sbin/useradd" exit=0 fsgid=0 fsuid=0 gid=0 items=0 name="smbd.log" 
path="/var/log/samba/smbd.log" pid=2588 
scontext=system_u:system_r:useradd_t:s0 sgid=0 
subj=system_u:system_r:useradd_t:s0 suid=0 tclass=file 
tcontext=system_u:object_r:samba_log_t:s0 tty=(none) uid=0 

Comment 5 Daniel Walsh 2007-03-20 16:04:02 UTC
Fixed in selinux-policy-2.4.6-46

Comment 6 Markku Kolkka 2007-03-27 08:25:27 UTC
I can't test joining machines at the moment, but selinux-policy-2.4.6-46 breaks
user management with User Manager for Domains. Adding or deleting users causes
SELinux denials, and probably the same would happen with machine accounts.

avc: denied { search } for comm="smbd" dev=dm-0 egid=0 euid=0
exe="/usr/sbin/smbd" exit=-13 fsgid=0 fsuid=0 gid=0 items=0 name="bin" pid=3068
scontext=system_u:system_r:smbd_t:s0 sgid=0 subj=system_u:system_r:smbd_t:s0
suid=0 tclass=dir tcontext=system_u:object_r:bin_t:s0 tty=(none) uid=0 

Comment 7 Daniel Walsh 2007-03-27 13:56:28 UTC
Fixed in selinux-policy-2.4.6-48

Comment 8 Markku Kolkka 2007-04-04 08:55:47 UTC
With selinux-policy-targeted-2.4.6-49.fc6 User Manager for Domains remains
broken, but the error has changed. Trying to add a new user gives:

avc: denied { read } for comm="smbd" dev=dm-0 egid=0 euid=0 exe="/usr/sbin/smbd"
exit=-13 fsgid=0 fsuid=0 gid=0 items=0 name="sh" pid=3059
scontext=system_u:system_r:smbd_t:s0 sgid=0 subj=system_u:system_r:smbd_t:s0
suid=0 tclass=lnk_file tcontext=system_u:object_r:bin_t:s0 tty=(none) uid=0 

Comment 9 Daniel Walsh 2007-04-05 13:17:10 UTC
Fixed in selinux-policy-2.4.6-52

Comment 10 Markku Kolkka 2007-04-12 09:33:17 UTC
I tested again joining machines to the domain with 
selinux-policy-targeted-2.4.6-54.fc6 and it still doesn't work. The denial 
messages keep changing with each version but the final result remains the 
same. This time the message is:

avc: denied { read } for comm="sh" dev=dm-2 egid=0 euid=0 exe="/bin/bash" 
exit=-13 fsgid=0 fsuid=0 gid=0 items=0 name="adduser" pid=2710 
scontext=system_u:system_r:smbd_t:s0 sgid=0 subj=system_u:system_r:smbd_t:s0 
suid=0 tclass=lnk_file tcontext=system_u:object_r:sbin_t:s0 tty=(none) uid=0 

Comment 11 Daniel Walsh 2007-04-12 13:03:22 UTC
If you add that this allow rule using

grep smbd_t /var/log/audit/audit.log | audit2allow -M mysamba
semodule -i mysamba.pp

Does it work?

If not, try setenforce 0 and gather all the AVC messages.

We have tested this on FC7/Rawhide and it is working now.
I will add a rule to allow this in the next build, but I want to fix this.


Comment 12 Markku Kolkka 2007-04-13 09:36:57 UTC
> grep smbd_t /var/log/audit/audit.log | audit2allow -M mysamba
> semodule -i mysamba.pp

Yes, this worked.


Comment 13 Daniel Walsh 2007-05-17 16:28:52 UTC
Fixed in selinux-policy-2.4.6-69


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