network: *un*set the firewalld zone while shutting down a network

When a bridge device for a virtual network had been placed in a
firewalld zone while starting the network, then even after the network
is shut down and the bridge device is deleted, its name will still
show up in the list of interfaces for whichever zone it had been in,
and this setting will persist through the next time a device with the
same name is created (until a zone is once again explicitly set, or
the device is removed via a firewalld API call).

Usually this isn't a problem, but in the case of forward mode='open',
someone might start the network once with a zone specified, then
shut down the network, remove the zone from its config, and start it
again; in this case the bridge device would come up using the zone
from the previous time it was started.

The solution to this is to remove the interface from whatever zone it
is in as the network is being shut down. There is no downside to doing
this, since the device is going to be deleted anyway. Note that
forward mode='bridge' uses a bridge device that was created outside of
libvirt, and libvirt won't be deleting that bridge, so we take care to
not unset the zone in that case.

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Martin Kletzander <mkletzan@redhat.com>

src/libvirt_private.syms

@@ -2451,6 +2451,7 @@ virFirewallDGetPolicies;
 virFirewallDGetVersion;
 virFirewallDGetZones;
 virFirewallDInterfaceSetZone;
+virFirewallDInterfaceUnsetZone;
 virFirewallDIsRegistered;
 virFirewallDPolicyExists;
 virFirewallDSynchronize;

src/network/bridge_driver.c

@@ -2127,6 +2127,8 @@ networkStartNetworkVirtual(virNetworkDriverState *driver,
         def->forward.type != VIR_NETWORK_FORWARD_OPEN)
         networkRemoveFirewallRules(obj);
 
+    networkUnsetBridgeZone(def);
+
     virNetworkObjUnrefMacMap(obj);
 
     ignore_value(virNetDevBridgeDelete(def->bridge));
@@ -2165,6 +2167,8 @@ networkShutdownNetworkVirtual(virNetworkObj *obj)
     if (def->forward.type != VIR_NETWORK_FORWARD_OPEN)
         networkRemoveFirewallRules(obj);
 
+    networkUnsetBridgeZone(def);
+
     ignore_value(virNetDevBridgeDelete(def->bridge));
 
     /* See if its still alive and really really kill it */

src/network/bridge_driver_linux.c

@@ -392,6 +392,20 @@ networkSetBridgeZone(virNetworkDef *def)
 }
 
 
+void
+networkUnsetBridgeZone(virNetworkDef *def)
+{
+    /* If there is a libvirt-managed bridge device remove it from any
+     * zone it had been placed in as a part of deleting the bridge.
+     * DO NOT CALL THIS FOR 'bridge' forward mode, since that
+     * bridge is not managed by libvirt.
+     */
+    if (def->bridge && def->forward.type != VIR_NETWORK_FORWARD_BRIDGE
+        && virFirewallDIsRegistered() == 0) {
+        virFirewallDInterfaceUnsetZone(def->bridge);
+    }
+}
+
 int
 networkAddFirewallRules(virNetworkDef *def,
                         virFirewallBackend firewallBackend,

src/network/bridge_driver_nop.c

@@ -51,6 +51,12 @@ networkSetBridgeZone(virNetworkDef *def)
 }
 
 
+void
+networkUnsetBridgeZone(virNetworkDef *def G_GNUC_UNUSED)
+{
+}
+
+
 int networkAddFirewallRules(virNetworkDef *def G_GNUC_UNUSED,
                             virFirewallBackend firewallBackend,
                             virFirewall **fwRemoval G_GNUC_UNUSED)

src/network/bridge_driver_platform.h

@@ -38,4 +38,6 @@ int networkAddFirewallRules(virNetworkDef *def,
                             virFirewallBackend firewallBackend,
                             virFirewall **fwRemoval);
 
+void networkUnsetBridgeZone(virNetworkDef *def);
+
 void networkRemoveFirewallRules(virNetworkObj *obj);

src/util/virfirewalld.c

@@ -449,6 +449,29 @@ virFirewallDInterfaceSetZone(const char *iface,
 }
 
 
+int
+virFirewallDInterfaceUnsetZone(const char *iface)
+{
+    GDBusConnection *sysbus = virGDBusGetSystemBus();
+    g_autoptr(GVariant) message = NULL;
+
+    if (!sysbus)
+        return -1;
+
+    message = g_variant_new("(ss)", "", iface);
+
+    return virGDBusCallMethod(sysbus,
+                             NULL,
+                             NULL,
+                             NULL,
+                             VIR_FIREWALL_FIREWALLD_SERVICE,
+                             "/org/fedoraproject/FirewallD1",
+                             "org.fedoraproject.FirewallD1.zone",
+                             "removeInterface",
+                             message);
+}
+
+
 void
 virFirewallDSynchronize(void)
 {

src/util/virfirewalld.h

@@ -46,4 +46,6 @@ int virFirewallDApplyRule(virFirewallLayer layer,
 int virFirewallDInterfaceSetZone(const char *iface,
                                  const char *zone);
 
+int virFirewallDInterfaceUnsetZone(const char *iface);
+
 void virFirewallDSynchronize(void);