auditd: add possibility to override config template (#685)

* make template overrideable

by referencing the auditd.conf.j2 template, a custom template can be provided to the role.

Signed-off-by: Dennis Lerch <[email protected]>

* extend auditd config

make freq and log_file configurable
implement write_logs with it's default value in order to be able to disable log writing

Signed-off-by: Dennis Lerch <[email protected]>

* Extend README.md documentation by new variables

reorder `os_auditd_log_format` to keep sequence from defaults

Signed-off-by: Dennis Lerch <[email protected]>

---------

Signed-off-by: Dennis Lerch <[email protected]>

roles/os_hardening/templates/etc/audit/auditd.conf.j2

@@ -1,12 +1,13 @@
 {{ ansible_managed | comment }}
 # Generated by Ansible role {{ ansible_role_name }}
 
-log_file = /var/log/audit/audit.log
+write_logs = {{ os_auditd_write_logs | bool | ternary('yes', 'no') }}
+log_file = {{ os_auditd_log_file }}
 log_format = {{ os_auditd_log_format }}
 log_group = {{ os_auditd_log_group }}
 priority_boost = 4
 flush = {{ os_auditd_flush }}
-freq = 20
+freq = {{ os_auditd_freq }}
 num_logs = {{ os_auditd_num_logs }}
 disp_qos = lossy
 dispatcher = /sbin/audispd