Description of problem:
Upon opening an .mp4 file in Firefox, installation gstreamer plugins happens and SELinux reports this.
SELinux is preventing gst-plugin-scan from 'execmod' accesses on the file /usr/lib/libmpg123.so.0.36.4.

*****  Plugin allow_execmod (91.4 confidence) suggests  **********************

If you want to allow gst-plugin-scan to have execmod access on the libmpg123.so.0.36.4 file
Then you need to change the label on '/usr/lib/libmpg123.so.0.36.4'
Do
# semanage fcontext -a -t textrel_shlib_t '/usr/lib/libmpg123.so.0.36.4'
# restorecon -v '/usr/lib/libmpg123.so.0.36.4'

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

If you believe that gst-plugin-scan should be allowed execmod access on the libmpg123.so.0.36.4 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 gst-plugin-scan /var/log/audit/audit.log | audit2allow -M mypol
# semodule -i mypol.pp

Additional Information:
Source Context                unconfined_u:unconfined_r:mozilla_plugin_t:s0-s0:c
                              0.c1023
Target Context                system_u:object_r:lib_t:s0
Target Objects                /usr/lib/libmpg123.so.0.36.4 [ file ]
Source                        gst-plugin-scan
Source Path                   gst-plugin-scan
Port                          <Unknown>
Host                          (removed)
Source RPM Packages           
Target RPM Packages           libmpg123-1.14.3-1.fc18.i686
Policy RPM                    selinux-policy-3.11.1-73.fc18.noarch
Selinux Enabled               True
Policy Type                   targeted
Enforcing Mode                Enforcing
Host Name                     (removed)
Platform                      Linux (removed) 3.7.4-204.fc18.i686 #1 SMP Wed Jan
                              23 17:08:59 UTC 2013 i686 i686
Alert Count                   1
First Seen                    2013-01-27 21:37:35 CET
Last Seen                     2013-01-27 21:37:35 CET
Local ID                      1ebc59b5-d0dc-4f21-b1e8-209691307a9a

Raw Audit Messages
type=AVC msg=audit(1359319055.406:362): avc:  denied  { execmod } for  pid=11716 comm="gst-plugin-scan" path="/usr/lib/libmpg123.so.0.36.4" dev="sda3" ino=1322172 scontext=unconfined_u:unconfined_r:mozilla_plugin_t:s0-s0:c0.c1023 tcontext=system_u:object_r:lib_t:s0 tclass=file


Hash: gst-plugin-scan,mozilla_plugin_t,lib_t,file,execmod

audit2allow

#============= mozilla_plugin_t ==============
allow mozilla_plugin_t lib_t:file execmod;

audit2allow -R

#============= mozilla_plugin_t ==============
allow mozilla_plugin_t lib_t:file execmod;


Additional info:
hashmarkername: setroubleshoot
kernel:         3.7.4-204.fc18.i686
type:           libreport

Potential duplicate: bug 836692