[CentOS] Customizing SELinux Policy

Alain Reguera Delgado alain.reguera at gmail.com
Mon Oct 6 01:13:28 UTC 2008


Hi Guys,

After some moths the server has been running in SELinux Permesive mode
... Some avc:  denied messages has been recored ... I thought it was
time to go to the next step and set SELinux Enforcing mode in the
server ... it is a mail(postfix+cyrus+sasl), web, snmp with mrtg,
squid sever with a local TLS configured for webmail access ... I took
a look to the Deployment Guide about how to do it ... and tried to
build modules with audit2allow from the /var/log/message

The modules seem to work fine, because old avc denied messages
desappeard ... but some messages like the following appear at
/var/log/messages when I do a semodule -i modulename or semodule -r
modulename :

Oct  5 20:16:11 orion kernel: : exe="?" (sauid=81, hostname=?, addr=?,
terminal=?)'
Oct  5 20:16:11 orion kernel: audit(1223252171.572:8): policy loaded
auid=4294967295 ses=4294967295
Oct  5 20:16:41 orion kernel: audit(1223252201.673:9): user pid=2172
uid=81 auid=4294967295 subj=system_u:system_r:system_dbus
d_t:s0 msg='avc:  received policyload notice (seqno=3)
Oct  5 20:16:41 orion kernel: : exe="?" (sauid=81, hostname=?, addr=?,
terminal=?)'
Oct  5 20:16:41 orion kernel: audit(1223252201.676:10): policy loaded
auid=4294967295 ses=4294967295
Oct  5 20:17:51 orion kernel: audit(1223252271.462:11): user pid=2172
uid=81 auid=4294967295 subj=system_u:system_r:system_dbu
sd_t:s0 msg='avc:  received policyload notice (seqno=4)
Oct  5 20:17:51 orion kernel: : exe="?" (sauid=81, hostname=?, addr=?,
terminal=?)'
Oct  5 20:17:51 orion kernel: audit(1223252271.464:12): policy loaded
auid=4294967295 ses=4294967295
Oct  5 20:19:06 orion kernel: audit(1223252346.208:13): user pid=2172
uid=81 auid=4294967295 subj=system_u:system_r:system_dbu
sd_t:s0 msg='avc:  received policyload notice (seqno=5)
Oct  5 20:19:06 orion kernel: : exe="?" (sauid=81, hostname=?, addr=?,
terminal=?)'
Oct  5 20:19:06 orion kernel: audit(1223252346.211:14): policy loaded
auid=4294967295 ses=4294967295
Oct  5 20:19:11 orion kernel: audit(1223252351.331:15): user pid=2172
uid=81 auid=4294967295 subj=system_u:system_r:system_dbu
sd_t:s0 msg='avc:  received policyload notice (seqno=6)

Also, in the /var/log/httpd/ssl_error_log the following messages appear too:

[Sun Oct 05 19:58:19 2008] [warn] RSA server certificate is a CA
certificate (BasicConstraints: CA == TRUE !?)
[Sun Oct 05 19:58:19 2008] [warn] RSA server certificate CommonName
(CN) `orion.ciget.cienfuegos.cu' does NOT match server nam
e!?

Really rare to me because that name `orion.ciget.cienfuegos.cu' is the
actual server hostname. When try to connect to the webmail through
https:// can't connect to it, the browser reports connection failed
after a waiting of a few seconds. http:// works as expected.

This machine is fully updated in CentOS-5.2.

Linux orion.ciget.cienfuegos.cu 2.6.18-92.1.13.el5 #1 SMP Wed Sep 24
19:33:52 EDT 2008 i686 i686 i386 GNU/Linux

Could you suggest something ? ...

Thank you very much guys,
al.


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