SELinux alert whenever firefox is launched

[Gaurav Prabhu]

Whenever I launch Mozilla Firefox, I get the following prompt from SELinux. I have disabled SELinux but still I'm eager to know what does this means.

Summary:

SELinux is preventing /usr/lib/nspluginwrapper/plugin-config from making the
program stack executable.

Detailed Description:

[SELinux is in permissive mode. This access was not denied.]

The plugin-config application attempted to make its stack executable. This is a
potential security problem. This should never ever be necessary. Stack memory is
not executable on most OSes these days and this will not change. Executable
stack memory is one of the biggest security problems. An execstack error might
in fact be most likely raised by malicious code. Applications 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. If plugin-config does not work and you need it to
work, you can configure SELinux temporarily to allow this access until the
application is fixed. Please file a bug report.

Allowing Access:

Sometimes a library is accidentally marked with the execstack flag, if you find
a library with this flag you can clear it with the execstack -c LIBRARY_PATH.
Then retry your application. If the app continues to not work, you can turn the
flag back on with execstack -s LIBRARY_PATH. Otherwise, if you trust
plugin-config to run correctly, you can change the context of the executable to
execmem_exec_t. "chcon -t execmem_exec_t
'/usr/lib/nspluginwrapper/plugin-config'" 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 execmem_exec_t
'/usr/lib/nspluginwrapper/plugin-config'"

Fix Command:

chcon -t execmem_exec_t '/usr/lib/nspluginwrapper/plugin-config'

Additional Information:

Source Context                unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1
                              023
Target Context                unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1
                              023
Target Objects                None [ process ]
Source                        plugin-config
Source Path                   /usr/lib/nspluginwrapper/plugin-config
Port                          <Unknown>
Host                          CoolG5
Source RPM Packages           nspluginwrapper-1.3.0-8.fc12
Target RPM Packages           
Policy RPM                    selinux-policy-3.6.32-41.fc12
Selinux Enabled               True
Policy Type                   targeted
MLS Enabled                   True
Enforcing Mode                Permissive
Plugin Name                   allow_execstack
Host Name                     CoolG5
Platform                      Linux CoolG5 2.6.31.5-127.fc12.i686 #1 SMP Sat Nov
                              7 21:41:45 EST 2009 i686 i686
Alert Count                   4
First Seen                    Mon 28 Dec 2009 04:16:57 PM IST
Last Seen                     Tue 29 Dec 2009 08:57:50 PM IST
Local ID                      90a2a558-89b1-4cf3-807f-9890c2505427
Line Numbers                  

Raw Audit Messages            

node=CoolG5 type=AVC msg=audit(1262100470.281:27): avc:  denied  { execstack } for  pid=3498 comm="plugin-config" scontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tcontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tclass=process

node=CoolG5 type=SYSCALL msg=audit(1262100470.281:27): arch=40000003 syscall=125 success=yes exit=0 a0=bfbbe000 a1=1000 a2=1000007 a3=bfbb6140 items=0 ppid=3496 pid=3498 auid=500 uid=500 gid=500 euid=0 suid=0 fsuid=0 egid=500 sgid=500 fsgid=500 tty=(none) ses=1 comm="plugin-config" exe="/usr/lib/nspluginwrapper/plugin-config" subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key=(null)

[Hlingler]

The plugin-config application attempted to make its stack executable. This is a
potential security problem. This should never ever be necessary. Stack memory is
not executable on most OSes these days and this will not change. Executable
stack memory is one of the biggest security problems. An execstack error might
in fact be most likely raised by malicious code. Applications are sometimes
coded incorrectly and request this permission.

The explanation in the printed message seems rather clear to me. What is the question ?

V

[Gaurav Prabhu]

But is that dangerous?

[domg472]

What kind of plugins/add-ons do you have installed? It *may* be that one of the plug-ins is causing this.

[lukea]

Personally I just disable SELinux for workstations, it just throws up warnings constantly and is nothing but a pita.

[Gaurav Prabhu]

Originally Posted by domg472

What kind of plugins/add-ons do you have installed? It *may* be that one of the plug-ins is causing this.

Its just the adblock plus & echofon(Twitterfox). I have used Fedora before but never ever encountered such prompt from SELinux.

[domg472]

I am not sure but it may be that "echofon(Twitterfox)" is causing this issue. I am aware that Firefox (32bit) requires or at some point required the execmem permission but i am not aware of similar issue for the execstack permission.

I would try and see if this still happens when you have the plugin(s) and/or addon(s) de- installed.