Do not try to set up default gateway without an IP address

If the container has no IP address (because it will be assigned via DHCP later),
setting up a default route fails with a warning message.

While this is harmless, the default route should be omitted instead.

1 files changed, 4 insertions, 0 deletions

diff --git a/src/firejail/network_main.c b/src/firejail/network_main.c
index 6800bde8d..ad297efc7 100644
--- a/src/firejail/network_main.c
+++ b/src/firejail/network_main.c
@@ -246,6 +246,10 @@ void net_check_cfg(void) {
         if (cfg.defaultgw)
                 check_default_gw(cfg.defaultgw);
         else {
+    // if the first network has no assigned address,
+    // do not try to set up a gateway, because it will fail
+    if (cfg.bridge0.arg_ip_none)
+      return;
                 // first network is a regular bridge
                 if (cfg.bridge0.macvlan == 0)
                         cfg.defaultgw = cfg.bridge0.ip;