roles/common: Use nftables on Ubuntu 20.04 as well

This mostly copies the Debian 11 nftables setup and includes a play
to clean up the old firewalld settings, timers, etc.

roles/common/tasks/firewall_Ubuntu.yml

@@ -1,7 +1,14 @@
 ---
+# Ubuntu 20.04 will use nftables directly, with no firewalld.
+# Ubuntu 18.04 will use firewalld with the nftables backend.
+# Ubuntu 16.04 will use firewalld with the iptables backend.
 
 - block:
+  - include_tasks: firewall_Ubuntu_cleanup.yml
+    when: ansible_distribution_version is version('20.04', '==')
+
   - name: Set Ubuntu firewall packages
+    when: ansible_distribution_version is version('20.04', '<')
     set_fact:
       ubuntu_firewall_packages:
         - firewalld
@@ -9,47 +16,57 @@
         - fail2ban
         - python3-systemd # for fail2ban systemd backend
 
-  - name: Install firewalld and deps
-    when: ansible_distribution_version is version('16.04', '>=')
+  - name: Set Ubuntu firewall packages
+    when: ansible_distribution_version is version('20.04', '>=')
+    set_fact:
+      ubuntu_firewall_packages:
+        - fail2ban
+        - libnet-ip-perl # for aggregate-cidr-addresses.pl
+        - nftables
+        - python3-systemd
+
+  - name: Install firewall packages
     apt: pkg={{ ubuntu_firewall_packages }} state=present
 
   - name: Remove ufw
     when: ansible_distribution_version is version('16.04', '>=')
     apt: pkg=ufw state=absent
 
-  # I'm not sure why, but you can use firewalld with the nftables backend even
-  # if nftables itself is not installed. In that case the only way to see the
-  # currently active rules is with firewall-cmd. I prefer installing nftables
-  # so that we can have somewhat of a parallel with iptables:
-  #
-  #   nft list ruleset
-  #
-  # See: https://firewalld.org/2018/07/nftables-backend
-  - name: Install nftables
-    when: ansible_distribution_version is version('20.04', '==')
-    apt: pkg=nftables state=present
+  - name: Start and enable nftables
+    when: ansible_distribution_version is version('20.04', '>=')
+    systemd: name=nftables state=started enabled=yes
 
-  - name: Use nftables backend in firewalld
-    when: ansible_distribution_version is version('20.04', '==')
-    lineinfile:
-      dest: /etc/firewalld/firewalld.conf
-      regexp: '^FirewallBackend=iptables$'
-      line: 'FirewallBackend=nftables'
+  - name: Copy nftables.conf
+    when: ansible_distribution_version is version('20.04', '>=')
+    template: src=nftables.conf.j2 dest=/etc/nftables.conf owner=root mode=0644
     notify:
-      - restart firewalld
+      - reload nftables
+
+  - name: Create /etc/nftables extra config directory
+    when: ansible_distribution_version is version('20.04', '>=')
+    file: path=/etc/nftables state=directory owner=root mode=0755
+
+  - name: Copy extra nftables configuration files
+    when: ansible_distribution_version is version('20.04', '>=')
+    copy: src={{ item }} dest=/etc/nftables/{{ item }} owner=root group=root mode=0644 force=no
+    loop:
+      - spamhaus-ipv4.nft
+      - spamhaus-ipv6.nft
+    notify:
+      - reload nftables
 
   - name: Copy firewalld public zone file
-    when: ansible_distribution_version is version('16.04', '>=')
+    when: ansible_distribution_version is version('18.04', '<=')
     template: src=public.xml.j2 dest=/etc/firewalld/zones/public.xml owner=root mode=0600
 
   - name: Format public.xml firewalld zone file
-    when: ansible_distribution_version is version('16.04', '>=')
+    when: ansible_distribution_version is version('18.04', '<=')
     command: tidy -xml -iq -m -w 0 /etc/firewalld/zones/public.xml
     notify:
       - restart firewalld
 
-  - name: Copy ipsets of abusive IPs
-    when: ansible_distribution_version is version('16.04', '>=')
+  - name: Copy firewalld ipsets of abusive IPs
+    when: ansible_distribution_version is version('18.04', '<=')
     copy: src={{ item }} dest=/etc/firewalld/ipsets/{{ item }} owner=root group=root mode=0600
     loop:
       - abusers-ipv4.xml
@@ -59,30 +76,49 @@
     notify:
       - restart firewalld
 
-  - name: Copy Spamhaus update script
-    when: ansible_distribution_version is version('16.04', '>=')
+  - name: Copy Spamhaus firewalld update script
+    when: ansible_distribution_version is version('18.04', '<=')
     copy: src=update-spamhaus-lists.sh dest=/usr/local/bin/update-spamhaus-lists.sh mode=0755 owner=root group=root
 
-  - name: Copy Spamhaus systemd units
-    when: ansible_distribution_version is version('16.04', '>=')
+  - name: Copy Spamhaus firewalld systemd units
+    when: ansible_distribution_version is version('18.04', '<=')
     copy: src={{ item }} dest=/etc/systemd/system/{{ item }} mode=0644 owner=root group=root
     loop:
         - update-spamhaus-lists.service
         - update-spamhaus-lists.timer
-    register: spamhaus_systemd_units
+    register: spamhaus_firewalld_systemd_units
+
+  - name: Copy Spamhaus nftables update scripts
+    when: ansible_distribution_version is version('20.04', '>=')
+    copy: src={{ item }} dest=/usr/local/bin/{{ item }} mode=0755 owner=root group=root
+    loop:
+      - update-spamhaus-nftables.sh
+      - aggregate-cidr-addresses.pl
+
+  - name: Copy Spamhaus nftables systemd units
+    when: ansible_distribution_version is version('20.04', '>=')
+    copy: src={{ item }} dest=/etc/systemd/system/{{ item }} mode=0644 owner=root group=root
+    loop:
+        - update-spamhaus-nftables.service
+        - update-spamhaus-nftables.timer
+    register: spamhaus_nftables_systemd_units
 
   # need to reload to pick up service/timer/environment changes
   - name: Reload systemd daemon
     systemd: daemon_reload=yes
-    when: spamhaus_systemd_units is changed
+    when: spamhaus_firewalld_systemd_units is changed or
+          spamhaus_nftables_systemd_units is changed
 
-  - name: Start and enable Spamhaus update timer
-    when: ansible_distribution_version is version('16.04', '>=')
+  - name: Start and enable Spamhaus firewalld update timer
+    when: ansible_distribution_version is version('18.04', '<=')
     systemd: name=update-spamhaus-lists.timer state=started enabled=yes
-
     notify:
       - restart firewalld
 
+  - name: Start and enable Spamhaus nftables update timer
+    when: ansible_distribution_version is version('20.04', '>=')
+    systemd: name=update-spamhaus-nftables.timer state=started enabled=yes
+
   - include_tasks: fail2ban.yml
     when: ansible_distribution_version is version('16.04', '>=')
   tags: firewall

roles/common/tasks/firewall_Ubuntu_cleanup.yml

@@ -0,0 +1,40 @@
+---
+# Clean up previous firewalld configuration on Ubuntu 20.04, now that we are
+# migrating to a pure nftables configuration.
+
+- name: Stop and disable firewalld
+  systemd: name=nftables state=stopped enabled=no
+
+- name: Set Ubuntu firewall packages to remove
+  set_fact:
+    ubuntu_firewall_packages:
+      - firewalld
+      - tidy
+
+- name: Remove old firewall packages
+  apt: pkg={{ ubuntu_firewall_packages }} state=absent
+
+- name: Remove old firewalld zone and ipsets
+  file: dest={{ item }} state=absent
+  loop:
+    - /etc/firewalld/zones/public.xml
+    - /etc/firewalld/ipsets/abusers-ipv4.xml
+    - /etc/firewalld/ipsets/abusers-ipv6.xml
+    - /etc/firewalld/ipsets/spamhaus-ipv4.xml
+    - /etc/firewalld/ipsets/spamhaus-ipv6.xml
+
+- name: Stop and disable old Spamhaus firewalld systemd timer
+  systemd: name=update-spamhaus-lists.timer state=stopped enabled=no
+
+- name: Remove old Spamhaus firewalld update script and systemd units
+  file: dest=/usr/local/bin/update-spamhaus-lists.sh state=absent
+  loop:
+    - /usr/local/bin/update-spamhaus-lists.sh
+    - /etc/systemd/system/update-spamhaus-lists.service
+    - /etc/systemd/system/update-spamhaus-lists.timer
+
+# need to reload to pick up service/timer/environment changes
+- name: Reload systemd daemon
+  systemd: daemon_reload=yes
+
+# vim: set sw=2 ts=2:

roles/common/templates/etc/fail2ban/jail.d/sshd.local.j2

@@ -2,7 +2,7 @@
 enabled   = true
 # See: /etc/fail2ban/filter.d/sshd.conf
 filter    = sshd
-{% if ansible_distribution == 'Debian' and ansible_distribution_major_version is version('11', '>=') %}
+{% if (ansible_distribution == 'Debian' and ansible_distribution_major_version is version('11', '>=')) or (ansible_distribution == 'Ubuntu' and ansible_distribution_version is version('20.04', '>=')) %}
 # Integrate with nftables
 banaction=nftables[type=allports]
 {% else %}