From a02d766cf57fe740d24d9577c0399185a4197dfe Mon Sep 17 00:00:00 2001
From: lapineige <lapineige@users.noreply.github.com>
Date: Tue, 20 Apr 2021 09:19:31 +0200
Subject: [PATCH] Fail2ban helper

---
 scripts/_common.sh | 64 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)

diff --git a/scripts/_common.sh b/scripts/_common.sh
index 71401d9..91bef12 100644
--- a/scripts/_common.sh
+++ b/scripts/_common.sh
@@ -25,6 +25,70 @@ function set_permissions {
 # EXPERIMENTAL HELPERS
 #=================================================
 
+#=================================================
+# EXPERIMENTAL HELPERS
+#=================================================
+
+# Create a dedicated fail2ban config (jail and filter conf files)
+#
+# usage: ynh_add_fail2ban_config log_file filter [max_retry [ports]]
+# | arg: log_file - Log file to be checked by fail2ban
+# | arg: failregex - Failregex to be looked for by fail2ban
+# | arg: max_retry - Maximum number of retries allowed before banning IP address - default: 3
+# | arg: ports - Ports blocked for a banned IP address - default: http,https
+ynh_add_fail2ban_config_temp () {
+   # Process parameters
+   logpath=$1
+   failregex=$2
+   max_retry=${3:-3}
+   ports=${4:-http,https}
+   
+  test -n "$logpath" || ynh_die "ynh_add_fail2ban_config expects a logfile path as first argument and received nothing."
+  test -n "$failregex" || ynh_die "ynh_add_fail2ban_config expects a failure regex as second argument and received nothing."
+  
+  finalfail2banjailconf="/etc/fail2ban/jail.d/$app.conf"
+  finalfail2banfilterconf="/etc/fail2ban/filter.d/$app.conf"
+  ynh_backup_if_checksum_is_different "$finalfail2banjailconf" 1
+  ynh_backup_if_checksum_is_different "$finalfail2banfilterconf" 1
+  
+  sudo tee $finalfail2banjailconf <<EOF
+[$app]
+enabled = true
+port = $ports
+filter = $app
+logpath = $logpath
+maxretry = $max_retry
+EOF
+
+  sudo tee $finalfail2banfilterconf <<EOF
+[INCLUDES]
+before = common.conf
+[Definition]
+failregex = $failregex
+ignoreregex =
+EOF
+
+  ynh_store_file_checksum "$finalfail2banjailconf"
+  ynh_store_file_checksum "$finalfail2banfilterconf"
+  
+  service fail2ban restart
+  local fail2ban_error="$(journalctl -u fail2ban | tail -n50 | grep "WARNING.*$app.*")"
+  if [ -n "$fail2ban_error" ]
+  then
+    echo "[ERR] Fail2ban failed to load the jail for $app" >&2
+    echo "WARNING${fail2ban_error#*WARNING}" >&2
+  fi
+}
+
+# Remove the dedicated fail2ban config (jail and filter conf files)
+#
+# usage: ynh_remove_fail2ban_config
+ynh_remove_fail2ban_config () {
+  ynh_secure_remove "/etc/fail2ban/jail.d/$app.conf"
+  ynh_secure_remove "/etc/fail2ban/filter.d/$app.conf"
+  sudo systemctl restart fail2ban
+}
+
 #=================================================
 # FUTURE OFFICIAL HELPERS
 #=================================================