[vino] Do not listen all if invalid interface is provided

[Ondrej Holy <oholy src gnome org>]

commit bfa1432ea1972b4272e3a7b8927f7c22094e5e44
Author: Ondrej Holy <oholy redhat com>
Date:   Tue May 22 21:06:06 2018 +0200

    Do not listen all if invalid interface is provided
    
    It is not a good idea from security point of view to listen all interfaces
    in case of invalid interface is provided. We should rather listen to nothing
    and print error in journal.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=796349

 server/libvncserver/sockets.c |   18 ++++++++++++------
 server/vino-server.c          |    3 +++
 2 files changed, 15 insertions(+), 6 deletions(-)
---
diff --git a/server/libvncserver/sockets.c b/server/libvncserver/sockets.c
index 746a3e5..45df6d5 100644
--- a/server/libvncserver/sockets.c
+++ b/server/libvncserver/sockets.c
@@ -152,9 +152,13 @@ rfbInitListenSock(rfbScreenInfoPtr rfbScreen)
     char *netIface = (char*)rfbScreen->netIface;
     int i;
 
-    if(netIface == NULL || if_nametoindex(netIface) == 0) {
-      if(netIface != NULL)
-        rfbLog("WARNING: This (%s) a invalid network interface, set to all\n", netIface);
+    if(netIface != NULL && strlen(netIface) > 0) {
+      if(if_nametoindex(netIface) == 0) {
+        rfbLog("(%s) is an invalid network interface\n", netIface);
+        return;
+      }
+    }
+    else {
       netIface = NULL;
     }
 
@@ -748,9 +752,11 @@ rfbSetNetworkInterface(rfbScreenInfoPtr rfbScreen, const char *netIface)
      rfbScreen->netIface = netIface;
   }
   else {
-     rfbScreen->netIface = NULL;
-     if(netIface != NULL)
-        rfbLog("WARNING: This (%s) a invalid network interface, set to all\n", netIface);
+    rfbScreen->netIface = NULL;
+    if(netIface != NULL && strlen(netIface) > 0) {
+      rfbLog("(%s) is an invalid network interface\n", netIface);
+      return FALSE;
+    }
   }
 
   rfbLog("Re-binding socket to listen for VNC connections on TCP port %d in (%s) interface\n",
diff --git a/server/vino-server.c b/server/vino-server.c
index 38b17e3..b8cd755 100644
--- a/server/vino-server.c
+++ b/server/vino-server.c
@@ -970,6 +970,9 @@ vino_server_init_io_channels(VinoServer *server)
     {
       dprintf (RFB, "%d ", rfb_screen->rfbListenSock[i]);
 
+      if (rfb_screen->rfbListenSock[i] == -1)
+        continue;
+
       server->priv->io_channel[i] = g_io_channel_unix_new (rfb_screen->rfbListenSock[i]);
       server->priv->io_watch[i]   = g_io_add_watch (server->priv->io_channel[i],
                                                     G_IO_IN|G_IO_PRI,