Selinux

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Enable SELinux in Amazon Linux

This took a little digging into; in order to get SELinux to function on Amazon AMI Linux you must carry out the following steps.
1. yum -y install policycoreutils selinux-policy-targeted
2. Now edit /etc/grub.conf and ensure your kernel line looks something like the following:

title Amazon Linux 2013.XX (3.XX.XX-XX.XX.amzn1.x86_64)
root (hd0)
kernel /boot/vmlinuz-3.XX.XX-XX.XX.amzn1.x86_64 root=LABEL=/ console=hvc0 selinux=1 security=selinux enforcing=1 LANG=en_US.UTF-8 KEYTABLE=us
initrd /boot/initramfs-3.XX.XX-XX.XX.amzn1.x86_64.img
Note the addition of “selinux=1 security=selinux enforcing=1”

3. Now: touch /.autorelabel
4. /sbin/new-kernel-pkg --package kernel --mkinitrd --make-default --dracut --depmod --install 3.XX.XX-XX.XX.amzn1.x86_64 || exit $?

Replacing the XX portions with your running kernel or you can use substitute in the uname -r output; this one liner script was obtained from: rpm -q --scripts kernel and is required to rebuild the initrd image such that the selinux settings can take effect.

Alternatively if there are kernel updates outstanding a yum -y update will achieve the same thing (selinux settings should persist); after all of this you can now reboot and wait. This will take a while to start back up as an selinux relabel is running (this is what the touch /.autorelabel achieves. All being well selinux should now be running enforcing in targeted mode; if not check your /etc/selinux/config file.