xdmcp: fix indirect queries

The XDMCP indirect query is supposed to be forwarded to the remote host
by gdm_xdmcp_send_forward_query() from daemon/gdm-xdmcp-display-factory.c

However, checking the return value of XdmcpFlush() we can see the call
fails with "Invalid Argument".

Looking at the gdm debug logs, the address (ic->chosen_address) used
there is correct but the port is 0 instead of 177, so the indirect query is never
forwarded to the selected host.

The address is set in on_hostname_selected() from
daemon/gdm-xdmcp-display-factory.c via getaddrinfo() but the service
field passed to getaddrinfo() is NULL, while using the actual XDMCP port
("177") fixes the issue and the indirect connection is successful.

committe://bugzilla.gnome.org/show_bug.cgi?id=665296

1 files changed, 6 insertions, 2 deletions

diff --git a/daemon/gdm-xdmcp-display-factory.c b/daemon/gdm-xdmcp-display-factory.c
index 71235362..a54a7342 100644
--- a/daemon/gdm-xdmcp-display-factory.c
+++ b/daemon/gdm-xdmcp-display-factory.c
@@ -1991,7 +1991,8 @@ on_hostname_selected (GdmXdmcpChooserDisplay *display,
         int              gaierr;
         GdmAddress      *address;
         IndirectClient  *ic;
-
+        gchar           *xdmcp_port;
+        
         g_debug ("GdmXdmcpDisplayFactory: hostname selected: %s",
                 hostname ? hostname : "(null)");
 
@@ -2011,10 +2012,13 @@ on_hostname_selected (GdmXdmcpChooserDisplay *display,
         /* this should convert IPv4 address to IPv6 if needed */
         hints.ai_flags = AI_V4MAPPED;
 
-        if ((gaierr = getaddrinfo (hostname, NULL, &hints, &ai_list)) != 0) {
+        xdmcp_port = g_strdup_printf ("%d", XDM_UDP_PORT);
+        if ((gaierr = getaddrinfo (hostname, xdmcp_port, &hints, &ai_list)) != 0) {
                 g_warning ("Unable to get address: %s", gai_strerror (gaierr));
+                g_free (xdmcp_port);
                 return;
         }
+        g_free (xdmcp_port);
 
         /* just take the first one */
         ai = ai_list;