handle docker rules & templatize custom rules

README.md

@@ -20,6 +20,7 @@ Role Ansible pour déployer un pare-feu iptables/ip6tables via un script shell e
 Variables par défaut dans [defaults/main.yml](defaults/main.yml).
 
 - firewall_public_interface: interface publique pour les logs optionnels. Si null, utilise ansible_default_ipv4.interface.
+- firewall_docker_safe: préserve les chaînes Docker lors d'un restart du firewall.
 - firewall_admin_sources: liste des CIDR autorisés sur les services admin.
 - firewall_admin_rules_ipv4: liste des règles IPv4 limitées aux sources admin.
 - firewall_public_tcp_ports_ipv4: ports TCP IPv4 ouverts publiquement.
@@ -32,6 +33,8 @@ firewall_admin_sources:
   - cidr: "203.0.113.10/32"
     comment: "bastion"
 
+firewall_docker_safe: true
+
 firewall_admin_rules_ipv4:
   - proto: "udp"
     dport: 51820
@@ -64,4 +67,5 @@ firewall_public_tcp_ports_ipv6:
 
 - Le script applique une politique restrictive (DROP sur INPUT/OUTPUT/FORWARD) puis ouvre explicitement les flux requis.
 - Toute erreur de syntaxe shell du template est validée avant déploiement via /bin/sh -n.
+- En mode docker-safe, les chaînes Docker existantes sont préservées pour éviter de casser la connectivité des conteneurs au restart.
 

defaults/main.yml

@@ -3,6 +3,10 @@
 # If null, ansible_default_ipv4.interface is used.
 firewall_public_interface: null
 
+# Preserve Docker-managed chains/rules when restarting the firewall.
+# When true, FORWARD chain is not reset if Docker chains are detected.
+firewall_docker_safe: true
+
 # IPv4 source networks allowed to access admin-restricted services.
 firewall_admin_sources:
   - cidr: "51.158.69.165/32"

templates/firewall.j2

@@ -11,6 +11,7 @@ NAME=firewall
 DESC="packet filter"
 
 PUBIF="{{ firewall_public_interface | default(ansible_default_ipv4.interface | default('eth0')) }}"
+FIREWALL_DOCKER_SAFE="{{ firewall_docker_safe | default(true) | ternary('1', '0') }}"
 #PRIVATEIF=eth1
 
 case "$1" in
@@ -18,10 +19,28 @@ case "$1" in
         echo -n "Initializing $DESC. \n"
 	### IPv4 ###
 	echo " \033[33mIPv4 : \033[0m"
+
+        HAS_DOCKER4=0
+        if [ "$FIREWALL_DOCKER_SAFE" = "1" ] && $IPT4 -S DOCKER >/dev/null 2>&1; then
+                HAS_DOCKER4=1
+        fi
+
+        # Reset only chains managed by this role.
+        $IPT4 -F INPUT
+        $IPT4 -F OUTPUT
+        $IPT4 -F ADMIN >/dev/null 2>&1 || true
+        $IPT4 -X ADMIN >/dev/null 2>&1 || true
+
+        if [ "$HAS_DOCKER4" -eq 0 ]; then
+                $IPT4 -F FORWARD
+                $IPT4 -P FORWARD DROP
+        else
+                echo " * Docker detected, preserving IPv4 FORWARD chain : \033[32m[OK] \033[0m"
+        fi
+
 	# DROP all incomming traffic
         $IPT4 -P INPUT DROP
 	$IPT4 -P OUTPUT DROP
-	$IPT4 -P FORWARD DROP
 	echo " * Deny all input and output IPv4 connections : \033[32m[OK] \033[0m"
 
 	# Unlimited access to loopback
@@ -67,10 +86,26 @@ case "$1" in
 
 	### IPv6 ###
 	echo " \033[33mIPv6 : \033[0m"
+
+        HAS_DOCKER6=0
+        if [ "$FIREWALL_DOCKER_SAFE" = "1" ] && $IPT6 -S DOCKER >/dev/null 2>&1; then
+                HAS_DOCKER6=1
+        fi
+
+        # Reset only chains managed by this role.
+        $IPT6 -F INPUT
+        $IPT6 -F OUTPUT
+
+        if [ "$HAS_DOCKER6" -eq 0 ]; then
+                $IPT6 -F FORWARD
+                $IPT6 -P FORWARD DROP
+        else
+                echo " * Docker detected, preserving IPv6 FORWARD chain : \033[32m[OK] \033[0m"
+        fi
+
 	# DROP all incomming traffic
 	$IPT6 -P INPUT DROP
 	$IPT6 -P OUTPUT DROP
-	$IPT6 -P FORWARD DROP
         echo " * Deny all input and output IPv6 connections : \033[32m[OK] \033[0m"
 
         # Unlimited access to loopback
@@ -112,26 +147,43 @@ case "$1" in
 
   stop)
         echo -n "Resetting $DESC. \n"
+
+        HAS_DOCKER4=0
+        if [ "$FIREWALL_DOCKER_SAFE" = "1" ] && $IPT4 -S DOCKER >/dev/null 2>&1; then
+                HAS_DOCKER4=1
+        fi
+
+        HAS_DOCKER6=0
+        if [ "$FIREWALL_DOCKER_SAFE" = "1" ] && $IPT6 -S DOCKER >/dev/null 2>&1; then
+                HAS_DOCKER6=1
+        fi
+
         ### IPv4 ###
-        $IPT4 -F
-        $IPT4 -X
+        $IPT4 -F INPUT
+        $IPT4 -F OUTPUT
+        $IPT4 -F ADMIN >/dev/null 2>&1 || true
+        $IPT4 -X ADMIN >/dev/null 2>&1 || true
+        if [ "$HAS_DOCKER4" -eq 0 ]; then
+                $IPT4 -F FORWARD
                 $IPT4 -P FORWARD ACCEPT
+        else
+                echo " * Docker detected, preserving IPv4 FORWARD chain : \033[32m[OK] \033[0m"
+        fi
         $IPT4 -P INPUT ACCEPT
         $IPT4 -P OUTPUT ACCEPT
-        $IPT4 -t nat -F
-        $IPT4 -t nat -X
-        $IPT4 -t mangle -F
-        $IPT4 -t mangle -X
         echo " * Cleaning IPv4 chains and rules : \033[32m[OK] \033[0m"
 
         ### IPv6 ###
-        $IPT6 -F
-        $IPT6 -X
+        $IPT6 -F INPUT
+        $IPT6 -F OUTPUT
+        if [ "$HAS_DOCKER6" -eq 0 ]; then
+                $IPT6 -F FORWARD
                 $IPT6 -P FORWARD ACCEPT
+        else
+                echo " * Docker detected, preserving IPv6 FORWARD chain : \033[32m[OK] \033[0m"
+        fi
         $IPT6 -P INPUT ACCEPT
         $IPT6 -P OUTPUT ACCEPT
-        $IPT6 -t mangle -F
-        $IPT6 -t mangle -X
         echo " * Cleaning IPv6 chains and rules : \033[32m[OK] \033[0m"
         echo
         ;;