Added apprmor to Gentoo install

Created the security page and added details on how to install apparmor in
the gentoo-desktop-setup section.

docs/gentoo-desktop-setup/installation.md

@@ -83,7 +83,7 @@ PORTAGE_LOGDIR_CLEAN="find \"\${PORTAGE_LOGDIR}\" -type f ! -name \"summary.log*
 ACCEPT_LICENSE="-* @FREE"
 
 # USE flags
-USE="${USE} networkmanager -modemmanager wayland dbus elogind -systemd policykit pam man udev pipewire initramfs secureboot modules-sign dist-kernel" # ....
+USE="${USE} networkmanager -modemmanager wayland dbus elogind -systemd policykit pam apparmor man udev pipewire initramfs secureboot modules-sign dist-kernel" # ....
 
 # Emerge settings
 EMERGE_DEFAULT_OPTS="${EMERGE_DEFAULT_OPTS} --with-bdeps y"

docs/gentoo-desktop-setup/post-install/security.md

@@ -0,0 +1,20 @@
+Security is an important factor when it comes to an operating system. Hardening the system is done to prevent as many exploits as possible. There are multiple factors which should be considered.
+
+## Apparmor and LSM
+
+Apparmor is a Mandatory Access Control (MAC) system that restricts capabilities from a program on a computer. It can dissallow access to files which the program would not require. Make sure the `apparmor` USE flag is enabled and install the necessary programs:
+
+``` shell-session
+sh# emerge -av apparmor apparmor-utils
+sh# rc-update add apparmor boot
+```
+
+Then add apparmor and other Linux Security Modules (LSM) to the `cmdline` and rebuild the initramfs:
+
+``` title="/etc/kernel/cmdline"
+... apparmor=1 lsm=landlock,lockdown,yama,capability,integrity,apparmor
+```
+
+``` shell-session
+sh# emerge --config gentoo-kernel # or gentoo-kernel-bin etc.
+```

mkdocs.yml

@@ -101,6 +101,7 @@ nav:
       - 'Swap': gentoo-desktop-setup/post-install/swap.md
       - 'Users': gentoo-desktop-setup/post-install/users.md
       - 'Ccache': gentoo-desktop-setup/post-install/ccache.md
+      - 'Security': gentoo-desktop-setup/post-install/security.md
     - 'Graphical session':
       - 'Session manager': gentoo-desktop-setup/graphical-session/session-manager.md
       - 'Login manager': gentoo-desktop-setup/graphical-session/login-manager.md