feat(aegis): manage firewall and SSH hardening

AGENTS.md

@@ -158,8 +158,12 @@ The dotfile vars follow the same split: `desktop_common_dotfiles` carries mode-i
 - `aegis` is a remote Fedora CoreOS Raspberry Pi 4 node. Bootstrap it once with
   `ansible/bootstrap/aegis.bu`; the remaining configuration is applied by `profile_aegis` over SSH.
 - Fedora CoreOS is immutable. Do not add it to mutable Fedora package or shared dotfile roles.
-- `profile_aegis` owns rootful Podman Quadlets, persistent container state under `/var/lib`, and the
+- `profile_aegis` owns rootful Podman Quadlets, persistent container state under `/var/lib`, the
-  Podman auto-update timer. Keep Apple IDs and other credentials in Vault and use `no_log` for their
+  Podman auto-update timer, LAN-restricted firewalld rules, and SSH hardening. Keep
-  rendering.
+  `aegis_lan_subnet` and `aegis_adguard_web_port` host-specific; SSH permits only the declared
+  key-authenticated users, never root or password authentication. Keep Apple IDs and other
+  credentials in Vault and use `no_log` for their rendering.
+- The initial AdGuard Home wizard uses `aegis_adguard_web_port: 3000`. After selecting a different
+  UI port, update that host variable and rerun the playbook to close the previous port.
 - iCloudPD requires post-deployment interactive MFA initialization; its cookie/configuration state is
   persisted in `/var/lib/icloudpd/config`.

README.md

@@ -116,18 +116,30 @@ ansible-playbook ansible/site.yml --limit prometheus \
 
 ## Aegis
 
-`aegis` is a Raspberry Pi 4 running Fedora CoreOS. Provision it once with
+`aegis` is a Raspberry Pi 4 running Fedora CoreOS. Generate Ignition from
-`ansible/bootstrap/aegis.bu`, after replacing the SSH public-key placeholder:
+`ansible/bootstrap/aegis.bu` with the included Podman/Butane helper, then write the SD card with
+`arm-image-installer`:
 
 ```bash
-butane --strict --pretty --output aegis.ign ansible/bootstrap/aegis.bu
+ansible/bootstrap/generate-aegis-ign.sh --write IMAGE DEVICE
 ```
 
-The controller then manages it remotely as `core@aegis`; unlike local desktop profiles, Aegis is
+The controller manages it remotely as `pi@aegis`; unlike local desktop profiles, Aegis is
 intentionally an SSH inventory target. `profile_aegis` manages rootful Podman Quadlets for AdGuard
-Home and iCloudPD, persistent data under `/var/lib`, the Podman auto-update timer, and
+Home and iCloudPD, persistent data under `/var/lib`, the Podman auto-update timer, LAN-restricted
-`wake-ikaros`. Define `vault_aegis_icloudpd_apple_id` in Vault before applying it. iCloudPD still
+firewalld rules, SSH key-only access for `pi`, and `wake-ikaros`. Set the host-local
-requires interactive MFA initialization after its first deployment.
+`aegis_lan_subnet` and `aegis_adguard_web_port` values before applying it. The initial AdGuard Home
+wizard uses port `3000`; after choosing another web port, update `aegis_adguard_web_port` and rerun
+the playbook so the firewall only permits the selected port. Define
+`vault_aegis_icloudpd_apple_id` in Vault before applying it. iCloudPD still requires interactive MFA
+initialization after its first deployment.
+
+Validate the profile before deployment:
+
+```bash
+ANSIBLE_LOCAL_TEMP=/tmp/ansible-local \
+ansible-playbook ansible/site.yml --limit aegis --check --diff --ask-become-pass
+```
 
 ## NAS
 

ansible/bootstrap/aegis.bu

@@ -50,14 +50,6 @@ storage:
       contents:
         inline: |
           net.ipv4.ip_forward = 1
-    - path: /etc/hosts
-      mode: 0644
-      overwrite: true
-      contents:
-        inline: |
-          127.0.0.1   localhost
-          ::1         localhost
-          192.168.0.1 aegis
   links:
     - path: /etc/localtime
       target: ../usr/share/zoneinfo/Europe/Rome

ansible/inventory/host_vars/aegis.yml

@@ -5,4 +5,7 @@ ansible_user: pi
 ansible_become: true
 ansible_python_interpreter: /usr/bin/python3
 
+aegis_lan_subnet: 192.168.178.0/24
+aegis_adguard_web_port: 3000
+
 aegis_icloudpd_apple_id: "{{ vault_aegis_icloudpd_apple_id | default('') }}"

ansible/roles/profile_aegis/defaults/main.yml

@@ -7,3 +7,9 @@ aegis_icloudpd_synchronisation_interval: 86400
 aegis_icloudpd_apple_id: ""
 aegis_ikaros_mac_address: aa:bb:cc:dd:ee:ff
 aegis_wol_port: 9
+
+aegis_lan_subnet: CHANGEME_LAN_SUBNET
+aegis_firewalld_zone: public
+aegis_adguard_web_port: 3000
+aegis_ssh_allowed_users:
+  - pi

ansible/roles/profile_aegis/handlers/main.yml

@@ -1,4 +1,9 @@
 ---
+- name: Reload Aegis SSH
+  ansible.builtin.systemd:
+    name: sshd.service
+    state: reloaded
+
 - name: Restart Aegis Quadlet services
   ansible.builtin.systemd:
     name: "{{ item }}"

ansible/roles/profile_aegis/tasks/main.yml

@@ -7,6 +7,17 @@
     fail_msg: Define vault_aegis_icloudpd_apple_id before applying the Aegis profile.
   no_log: true
 
+- name: Require completed Aegis network placeholders
+  tags: [aegis, firewall, services]
+  ansible.builtin.assert:
+    that:
+      - aegis_lan_subnet != 'CHANGEME_LAN_SUBNET'
+      - aegis_firewalld_zone | length > 0
+      - aegis_adguard_web_port | int > 0
+      - aegis_adguard_web_port | int < 65536
+      - aegis_ssh_allowed_users | length > 0
+    fail_msg: Define the Aegis LAN subnet, firewalld zone, AdGuard web port, and SSH users.
+
 - name: Set Aegis hostname
   tags: [aegis, services]
   ansible.builtin.hostname:
@@ -53,6 +64,146 @@
   no_log: "{{ item.dest == 'icloudpd.container' }}"
   notify: Restart Aegis Quadlet services
 
+- name: Enable Aegis firewalld
+  tags: [aegis, firewall, services]
+  ansible.builtin.systemd:
+    name: firewalld.service
+    enabled: true
+    state: started
+
+- name: Render Aegis AdGuard web firewalld service
+  tags: [aegis, firewall]
+  ansible.builtin.template:
+    src: aegis-adguard-web.xml.j2
+    dest: /etc/firewalld/services/aegis-adguard-web.xml
+    owner: root
+    group: root
+    mode: "0644"
+
+- name: Reload firewalld custom services
+  tags: [aegis, firewall]
+  ansible.builtin.command:
+    argv:
+      - firewall-cmd
+      - --reload
+  changed_when: false
+  when: not ansible_check_mode
+
+- name: Remove unrestricted Aegis services from firewalld zone
+  tags: [aegis, firewall]
+  ansible.posix.firewalld:
+    service: "{{ item }}"
+    permanent: true
+    immediate: true
+    state: disabled
+    zone: "{{ aegis_firewalld_zone }}"
+  loop:
+    - ssh
+    - dns
+    - http
+    - aegis-adguard-web
+  loop_control:
+    label: "{{ item }}"
+
+- name: Allow Aegis services from the LAN only
+  tags: [aegis, firewall]
+  ansible.posix.firewalld:
+    rich_rule: "{{ item }}"
+    permanent: true
+    immediate: true
+    state: enabled
+    zone: "{{ aegis_firewalld_zone }}"
+  loop:
+    - 'rule family="ipv4" source address="{{ aegis_lan_subnet }}" service name="ssh" accept'
+    - 'rule family="ipv4" source address="{{ aegis_lan_subnet }}" service name="dns" accept'
+    - 'rule family="ipv4" source address="{{ aegis_lan_subnet }}" service name="aegis-adguard-web" accept'
+  loop_control:
+    label: "{{ item }}"
+
+- name: Check the standard Aegis SSH authorized keys file
+  tags: [aegis, ssh, services]
+  ansible.builtin.stat:
+    path: "{{ ansible_user_dir }}/.ssh/authorized_keys"
+  register: aegis_authorized_keys
+
+- name: Find Aegis SSH authorized key fragments
+  tags: [aegis, ssh, services]
+  ansible.builtin.find:
+    paths: "{{ ansible_user_dir }}/.ssh/authorized_keys.d"
+    file_type: file
+    recurse: false
+  register: aegis_authorized_key_fragments
+
+- name: Require an Aegis SSH authorized key before hardening
+  tags: [aegis, ssh, services]
+  ansible.builtin.assert:
+    that:
+      - >-
+        (aegis_authorized_keys.stat.exists and aegis_authorized_keys.stat.size | int > 0)
+        or aegis_authorized_key_fragments.matched | int > 0
+    fail_msg: Add a public key for the Ansible SSH user before disabling password authentication.
+
+- name: Ensure Aegis SSH configuration drop-in directory exists
+  tags: [aegis, ssh, services]
+  ansible.builtin.file:
+    path: /etc/ssh/sshd_config.d
+    state: directory
+    owner: root
+    group: root
+    mode: "0755"
+
+- name: Ensure Aegis SSH drop-ins are loaded before other settings
+  tags: [aegis, ssh, services]
+  ansible.builtin.lineinfile:
+    path: /etc/ssh/sshd_config
+    regexp: '^\s*Include\s+/etc/ssh/sshd_config\.d/\*\.conf\s*$'
+    line: Include /etc/ssh/sshd_config.d/*.conf
+    insertbefore: BOF
+    state: present
+    validate: "sshd -t -f %s"
+
+- name: Render Aegis SSH hardening drop-in
+  tags: [aegis, ssh, services]
+  ansible.builtin.template:
+    src: 00-aegis-hardening.conf.j2
+    dest: /etc/ssh/sshd_config.d/00-aegis-hardening.conf
+    owner: root
+    group: root
+    mode: "0600"
+  notify: Reload Aegis SSH
+
+- name: Validate Aegis SSH configuration
+  tags: [aegis, ssh, services]
+  ansible.builtin.command:
+    argv:
+      - sshd
+      - -t
+  changed_when: false
+  when: not ansible_check_mode
+
+- name: Read effective Aegis SSH daemon configuration
+  tags: [aegis, ssh, services]
+  ansible.builtin.command:
+    argv:
+      - sshd
+      - -T
+      - -C
+      - "user={{ ansible_user }},host={{ aegis_hostname }},addr=127.0.0.1"
+  register: aegis_sshd_effective_configuration
+  changed_when: false
+  when: not ansible_check_mode
+
+- name: Verify effective Aegis SSH hardening
+  tags: [aegis, ssh, services]
+  ansible.builtin.assert:
+    that:
+      - "'permitrootlogin no' in aegis_sshd_effective_configuration.stdout_lines"
+      - "'pubkeyauthentication yes' in aegis_sshd_effective_configuration.stdout_lines"
+      - "'passwordauthentication no' in aegis_sshd_effective_configuration.stdout_lines"
+      - "'kbdinteractiveauthentication no' in aegis_sshd_effective_configuration.stdout_lines"
+      - "'allowusers ' + (aegis_ssh_allowed_users | join(' ')) in aegis_sshd_effective_configuration.stdout_lines"
+  when: not ansible_check_mode
+
 - name: Install Wake-on-LAN helper for Ikaros
   tags: [aegis, wol]
   ansible.builtin.template:

ansible/roles/profile_aegis/templates/00-aegis-hardening.conf.j2

@@ -0,0 +1,6 @@
+# Managed by Ansible. Do not edit manually.
+PermitRootLogin no
+PubkeyAuthentication yes
+PasswordAuthentication no
+KbdInteractiveAuthentication no
+AllowUsers {{ aegis_ssh_allowed_users | join(' ') }}

ansible/roles/profile_aegis/templates/aegis-adguard-web.xml.j2

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<service>
+  <short>Aegis AdGuard Home web interface</short>
+  <description>AdGuard Home administrative web interface on Aegis.</description>
+  <port protocol="tcp" port="{{ aegis_adguard_web_port }}"/>
+</service>