Switching SELinux on and off

This is perhaps a weird section to begin with, but disabling SELinux is a commonly requested activity. Some vendors do not support their application running on a platform that has SELinux enabled. System administrators are generally reluctant to use security controls they do not understand or find too complex to maintain. Luckily, this number is diminishing, and SELinux is also capable of selectively disabling its access controls for a part of the system rather than requiring us to completely disable it.

Setting the global SELinux state

SELinux supports three major states that it can be in: disabled, permissive, and enforcing. These states are set in the /etc/selinux/config file, through the SELINUX variable. Take a look at the current setting:

$ grep ^SELINUX= /etc/selinux/config
SELINUX=enforcing

When the system init process loads the SELinux policy, the SELinux code checks the state that the administrator has configured. The states are described as follows:

• If...