Provide granular noop for ssh configuration (#789)

* Provide granular noop for shh configuration

We would like to have more fine grained options on applying or not specific configurations.

This commit let the user choose to noop some configuration with a few new
boolean variables.

Motivation for theses options are we may configure ourselves some (ssh host key
regeneration in a templating system) or we are not ready for others (ssh_kex
will break dist-upgrades, letting the operator without ssh).

Signed-off-by: seven beep <[email protected]>

* Provide granula noop for ssh configuration

We would like to have more fine grained options on applying or not specific configurations.

This commit let the user choose to disable configurations for `ssh_host_key_config`,
`ssh_ciphers_config`, `ssh_host_key_config`, `ssh_macs_config` by setting them
to False.

Motivation for theses options are we may configure ourselves some (ssh host key
regeneration in a templating system) or we are not ready for others (ssh_kex
will break dist-upgrades, letting the operator without ssh).

Signed-off-by: seven beep <[email protected]>

---------

Signed-off-by: seven beep <[email protected]>

roles/ssh_hardening/tasks/hardening.yml

@@ -39,19 +39,22 @@
   ansible.builtin.include_tasks: crypto_hostkeys.yml
   when:
     - ssh_server_hardening | bool
-    - not ssh_host_key_files
+    - ssh_host_key_files is undefined
 
 - name: Set default for ssh_macs if not supplied
   ansible.builtin.include_tasks: crypto_macs.yml
-  when: not ssh_macs
+  when:
+    - ssh_macs is undefined
 
 - name: Set default for ssh_ciphers if not supplied
   ansible.builtin.include_tasks: crypto_ciphers.yml
-  when: not ssh_ciphers
+  when:
+    - ssh_ciphers is undefined
 
 - name: Set default for ssh_kex if not supplied
   ansible.builtin.include_tasks: crypto_kex.yml
-  when: not ssh_kex
+  when:
+    - ssh_kex is undefined
 
 - name: Create revoked_keys and set permissions to root/600
   ansible.builtin.template: