Linux Foundation Exam CKS Topic 1 Question 18 Discussion

On the Cluster worker node, enforce the prepared AppArmor profile

#include

profile docker-nginx flags=(attach_disconnected,mediate_deleted) {

#include

network inet tcp,

network inet udp,

network inet icmp,

deny network raw,

deny network packet,

file,

umount,

deny /bin/** wl,

deny /boot/** wl,

deny /dev/** wl,

deny /etc/** wl,

deny /home/** wl,

deny /lib/** wl,

deny /lib64/** wl,

deny /media/** wl,

deny /mnt/** wl,

deny /opt/** wl,

deny /proc/** wl,

deny /root/** wl,

deny /sbin/** wl,

deny /srv/** wl,

deny /tmp/** wl,

deny /sys/** wl,

deny /usr/** wl,

audit /** w,

/var/run/nginx.pid w,

/usr/sbin/nginx ix,

deny /bin/dash mrwklx,

deny /bin/sh mrwklx,

deny /usr/bin/top mrwklx,

capability chown,

capability dac_override,

capability setuid,

capability setgid,

capability net_bind_service,

deny @{PROC}/* w, # deny write for all files directly in /proc (not in a subdir)

# deny write to files not in /proc//** or /proc/sys/**

deny @{PROC}/{[^1-9],[^1-9][^0-9],[^1-9s][^0-9y][^0-9s],[^1-9][^0-9][^0-9][^0-9]*}/** w,

deny @{PROC}/sys/[^k]** w, # deny /proc/sys except /proc/sys/k* (effectively /proc/sys/kernel)

deny @{PROC}/sys/kernel/{?,??,[^s][^h][^m]**} w, # deny everything except shm* in /proc/sys/kernel/

deny @{PROC}/sysrq-trigger rwklx,

deny @{PROC}/mem rwklx,

deny @{PROC}/kmem rwklx,

deny @{PROC}/kcore rwklx,

deny mount,

deny /sys/[^f]*/** wklx,

deny /sys/f[^s]*/** wklx,

deny /sys/fs/[^c]*/** wklx,

deny /sys/fs/c[^g]*/** wklx,

deny /sys/fs/cg[^r]*/** wklx,

deny /sys/firmware/** rwklx,

deny /sys/kernel/security/** rwklx,

}

Edit the prepared manifest file to include the AppArmor profile.

apiVersion: v1

kind: Pod

metadata:

name: apparmor-pod

spec:

containers:

- name: apparmor-pod

image: nginx

Finally, apply the manifests files and create the Pod specified on it.

Verify: Try to use commandping, top, sh