SELinux
2022-07-25


SELinux is a Linux Security Module (LSM). When the kernel does something like a permission check and it passes OK, the security module is queried right after to provide additional security checks. You will find SELinux on RedHat based distributions and Android. Another popular option is AppArmor, used for example in Ubuntu. There can only be one LSM is use at a time, so you won't ever use both of them at once.

SELinux provides additional context associated with certain paths to provide an extended permission model.

Directory listing with SELinux context:
$ ls -laRZ .

List possible context values:
$ semanage fcontext -l

Refresh assigned context values:
$ restorecon -Rv .

Change context:
$ chcon

To automatically refresh context values and relabel the system on reboot:
$ touch /.autorelabel