SELinux, VLC and text relocation

[Rahul Sundaram]

Hi

Summary:

SELinux is preventing vlc from loading 
/usr/lib/vlc/codec/librealvideo_plugin.so
which requires text relocation.

Detailed Description:

[SELinux is in permissive mode, the operation would have been denied but was
permitted due to permissive mode.]

The vlc application attempted to load 
/usr/lib/vlc/codec/librealvideo_plugin.so
which requires text relocation. This is a potential security problem. Most
libraries do not need this permission. Libraries are sometimes coded 
incorrectly
and request this permission. The SELinux Memory Protection Tests
(http://people.redhat.com/drepper/selinux-mem.html) web page explains how to
remove this requirement. You can configure SELinux temporarily to allow
/usr/lib/vlc/codec/librealvideo_plugin.so to use relocation as a workaround,
until the library is fixed. Please file a bug report
(http://bugzilla.redhat.com/bugzilla/enter_bug.cgi) against this package.

Allowing Access:

If you trust /usr/lib/vlc/codec/librealvideo_plugin.so to run correctly, 
you can
change the file context to textrel_shlib_t. "chcon -t textrel_shlib_t
'/usr/lib/vlc/codec/librealvideo_plugin.so'" You must also change the 
default
file context files on the system in order to preserve them even on a full
relabel. "semanage fcontext -a -t textrel_shlib_t
'/usr/lib/vlc/codec/librealvideo_plugin.so'"

Fix Command:

chcon -t textrel_shlib_t '/usr/lib/vlc/codec/librealvideo_plugin.so'

Additional Information:

Source Context 
unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1
                               023
Target Context                system_u:object_r:lib_t:s0
Target Objects                /usr/lib/vlc/codec/librealvideo_plugin.so 
[ file ]
Source                        vlc
Source Path                   /usr/bin/vlc
Port                          <Unknown>
Host                          sundaram
Source RPM Packages           vlc-core-0.9.4-1.fc10
Target RPM Packages           vlc-core-0.9.4-1.fc10
Policy RPM                    selinux-policy-3.5.12-3.fc10
Selinux Enabled               True
Policy Type                   targeted
MLS Enabled                   True
Enforcing Mode                Permissive
Plugin Name                   allow_execmod
Host Name                     sundaram
Platform                      Linux sundaram 2.6.27-13.fc10.i686
                               #1 SMP Wed Oct 15 02:06:26 EDT 2008 i686 i686
Alert Count                   1
First Seen                    Sat 18 Oct 2008 08:18:07 AM IST
Last Seen                     Sat 18 Oct 2008 08:18:07 AM IST
Local ID                      046cbf7a-5c30-4f56-8e3a-01169befcb34
Line Numbers

Raw Audit Messages

node=sundaram type=AVC msg=audit(1224298087.506:271): avc:  denied  { 
execmod } for  pid=25126 comm="vlc" 
path="/usr/lib/vlc/codec/librealvideo_plugin.so" dev=dm-0 ino=246161 
scontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 
tcontext=system_u:object_r:lib_t:s0 tclass=file

node=sundaram type=SYSCALL msg=audit(1224298087.506:271): arch=40000003 
syscall=125 success=yes exit=0 a0=7859000 a1=19000 a2=5 a3=bf8a3690 
items=0 ppid=1 pid=25126 auid=500 uid=500 gid=500 euid=500 suid=500 
fsuid=500 egid=500 sgid=500 fsgid=500 tty=(none) ses=1 comm="vlc" 
exe="/usr/bin/vlc" 
subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key=(null)


Rahul