--- gdm-2.20.11/daemon/gdm-daemon-config.c.orig	2010-06-03 03:06:25.000000000 +0200
+++ gdm-2.20.11/daemon/gdm-daemon-config.c	2018-04-22 21:53:51.242329643 +0200
@@ -1935,7 +1935,7 @@
 
 	} else {
 		if (console_notify) {
-			gchar *s = g_strdup_printf (C_(N_("XDMCP is disabled and GDM "
+			gchar *s = g_strdup (C_(N_("XDMCP is disabled and GDM "
 							  "cannot find any static server "
 							  "to start.  Aborting!  Please "
 							  "correct the configuration "
@@ -1993,7 +1993,7 @@
 
 	if G_UNLIKELY (uid == 0) {
 		if (console_notify) {
-			gchar *s = g_strdup_printf (C_(N_("The GDM user is set to be root, but "
+			gchar *s = g_strdup (C_(N_("The GDM user is set to be root, but "
 							  "this is not allowed since it can "
 							  "pose a security risk.  Please "
 							  "correct GDM configuration and "
@@ -2025,7 +2025,7 @@
 
 	if G_UNLIKELY (gid == 0) {
 		if (console_notify) {
-			gchar *s = g_strdup_printf (C_(N_("The GDM group is set to be root, but "
+			gchar *s = g_strdup (C_(N_("The GDM group is set to be root, but "
 							  "this is not allowed since it can "
 							  "pose a security risk. Please "
 							  "correct GDM configuration and "
--- gdm-2.20.11/daemon/slave.c.orig	2010-06-03 03:06:25.000000000 +0200
+++ gdm-2.20.11/daemon/slave.c	2018-04-22 22:15:02.428981793 +0200
@@ -265,7 +265,7 @@
 	} else {									\
 		/* evil! how this this happen */					\
 		if (slave_start_jmp_error_to_print != NULL)				\
-			gdm_error (slave_start_jmp_error_to_print);			\
+			gdm_error ("%s", slave_start_jmp_error_to_print);		\
 		gdm_error ("Bad (very very VERY bad!) things happening in signal");	\
 		_exit (DISPLAY_REMANAGE);						\
 	}										\
@@ -691,7 +691,7 @@
 	need_to_quit_after_session_stop = TRUE;
 
 	if (slave_start_jmp_error_to_print != NULL)
-		gdm_error (slave_start_jmp_error_to_print);
+		gdm_error ("%s", slave_start_jmp_error_to_print);
 	slave_start_jmp_error_to_print = NULL;
 
 	/* only if we're not hanging in session stop and getting a
@@ -720,7 +720,7 @@
 	need_to_quit_after_session_stop = TRUE;
 
 	if (slave_start_jmp_error_to_print != NULL)
-		gdm_error (slave_start_jmp_error_to_print);
+		gdm_error ("%s", slave_start_jmp_error_to_print);
 	slave_start_jmp_error_to_print = NULL;
 
 	gdm_debug ("term_quit: Final cleanup");
--- gdm-2.20.11/daemon/misc.c.orig	2010-06-03 03:06:25.000000000 +0200
+++ gdm-2.20.11/daemon/misc.c	2018-04-22 22:15:49.818981253 +0200
@@ -2222,7 +2222,7 @@
     va_end (args);
 
     /* Log to both syslog and stderr */
-    gdm_error (s);
+    gdm_error ("%s", s);
     if (getpid () == gdm_main_pid) {
 	    gdm_fdprintf (2, "%s\n", s);
     }