interface: don't segfault with an unknown protocol

diff --git a/interface.c b/interface.c
index a5675f7a77a35cc90d441fd755a0b028294219ab..60efc7e43950fc8f28bc97289cee59ea1a5089ca 100644 (file)
--- a/interface.c
+++ b/interface.c
@@ -241,7 +241,8 @@ interface_alloc(const char *name, struct blob_attr *attr)
 
        proto_attach_interface(iface, proto_name);
 
-       if (!(iface->proto_handler->flags & PROTO_FLAG_NODEV) &&
+       if (iface->proto_handler &&
+           !(iface->proto_handler->flags & PROTO_FLAG_NODEV) &&
            (cur = tb[IFACE_ATTR_IFNAME])) {
                dev = device_get(blobmsg_data(cur), true);
                if (dev)