SELinux is preventing /usr/lib64/firefox-6/firefox from using the execmem access on a process.

*****  Plugin catchall_boolean (47.5 confidence) suggests  *******************

If you want to allow unconfined executables to make their stack executable.  This should never, ever be necessary. Probably indicates a badly coded executable, but could indicate an attack. This executable should be reported in bugzilla
Then you must tell SELinux about this by enabling the 'allow_execstack' boolean.
Do
setsebool -P allow_execstack 1

*****  Plugin catchall_boolean (47.5 confidence) suggests  *******************

If you want to allow unconfined executables to map a memory region as both executable and writable, this is dangerous and the executable should be reported in bugzilla
Then you must tell SELinux about this by enabling the 'allow_execmem' boolean.
Do
setsebool -P allow_execmem 1

*****  Plugin catchall (6.38 confidence) suggests  ***************************

If you believe that firefox should be allowed execmem access on processes labeled unconfined_t 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 firefox /var/log/audit/audit.log | audit2allow -M mypol
# semodule -i mypol.pp

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                Unknown [ process ]
Source                        firefox
Source Path                   /usr/lib64/firefox-6/firefox
Port                          <Unknown>
Host                          localhost.localdomain
Source RPM Packages           firefox-6.0.2-1.fc15
Target RPM Packages           
Policy RPM                    selinux-policy-3.9.16-38.fc15
Selinux Enabled               True
Policy Type                   targeted
Enforcing Mode                Enforcing
Host Name                     localhost.localdomain
Platform                      Linux localhost.localdomain 2.6.40.4-5.fc15.x86_64
                              #1 SMP Tue Aug 30 14:38:32 UTC 2011 x86_64 x86_64
Alert Count                   2
First Seen                    Sun 25 Sep 2011 05:29:56 PM CEST
Last Seen                     Sun 25 Sep 2011 05:30:06 PM CEST
Local ID                      91ba1f5c-12a5-4342-ac7f-b7fcace3821a

Raw Audit Messages
type=AVC msg=audit(1316964606.78:92): avc:  denied  { execmem } for  pid=4570 comm="firefox" scontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tcontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tclass=process


type=SYSCALL msg=audit(1316964606.78:92): arch=x86_64 syscall=mmap success=no exit=EACCES a0=0 a1=10000 a2=7 a3=22 items=0 ppid=1879 pid=4570 auid=500 uid=500 gid=500 euid=500 suid=500 fsuid=500 egid=500 sgid=500 fsgid=500 tty=(none) ses=1 comm=firefox exe=/usr/lib64/firefox-6/firefox subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key=(null)

Hash: firefox,unconfined_t,unconfined_t,process,execmem

audit2allow

#============= unconfined_t ==============
#!!!! This avc can be allowed using one of the these booleans:
#     allow_execstack, allow_execmem

allow unconfined_t self:process execmem;

audit2allow -R

#============= unconfined_t ==============
#!!!! This avc can be allowed using one of the these booleans:
#     allow_execstack, allow_execmem

allow unconfined_t self:process execmem;