Prevent potential illegal memory access, move null pointer check to before dereference

dialogs/appearance-settings/main.c

@@ -167,8 +167,8 @@ cb_toolbar_style_combo_changed (GtkComboBox *combo)
 {
     gint active;
 
-    /* Get active item, prevent number outside the array */
-    active = CLAMP (gtk_combo_box_get_active (combo), 0, (gint) G_N_ELEMENTS (toolbar_styles_array));
+    /* Get active item, prevent number outside the array (stay within zero-index) */
+    active = CLAMP (gtk_combo_box_get_active (combo), 0, (gint) G_N_ELEMENTS (toolbar_styles_array)-1);
 
     /* Save setting */
     xfconf_channel_set_string (xsettings_channel, "/Gtk/ToolbarStyle", toolbar_styles_array[active]);
@@ -194,8 +194,8 @@ cb_hinting_style_combo_changed (GtkComboBox *combo)
 {
     gint active;
 
-    /* Get active item, prevent number outside the array */
-    active = CLAMP (gtk_combo_box_get_active (combo), 0, (gint) G_N_ELEMENTS (xft_hint_styles_array));
+    /* Get active item, prevent number outside the array (stay within zero-index) */
+    active = CLAMP (gtk_combo_box_get_active (combo), 0, (gint) G_N_ELEMENTS (xft_hint_styles_array)-1);
 
     /* Save setting */
     xfconf_channel_set_string (xsettings_channel, "/Xft/HintStyle", xft_hint_styles_array[active]);
@@ -206,8 +206,8 @@ cb_rgba_style_combo_changed (GtkComboBox *combo)
 {
     gint active;
 
-    /* Get active item, prevent number outside the array */
-    active = CLAMP (gtk_combo_box_get_active (combo), 0, (gint) G_N_ELEMENTS (xft_rgba_array));
+    /* Get active item, prevent number outside the array (stay within zero-index) */
+    active = CLAMP (gtk_combo_box_get_active (combo), 0, (gint) G_N_ELEMENTS (xft_rgba_array)-1);
 
     /* Save setting */
     xfconf_channel_set_string (xsettings_channel, "/Xft/RGBA", xft_rgba_array[active]);

dialogs/mouse-settings/main.c

@@ -1568,6 +1568,10 @@ mouse_settings_device_populate_store (GtkBuilder *builder,
             || g_str_has_prefix (device_info->name, "Virtual core XTEST"))
             continue;
 
+        /* cannot go any further without device name */
+        if (device_info->name == NULL)
+            continue;
+
         /* create a valid xfconf device name */
         xfconf_name = mouse_settings_device_xfconf_name (device_info->name);
 
@@ -1579,8 +1583,7 @@ mouse_settings_device_populate_store (GtkBuilder *builder,
                                            -1);
 
         /* check if we should select this device */
-        if (device_info->name != NULL
-            && opt_device_name != NULL
+        if (opt_device_name != NULL
             && strcmp (opt_device_name, device_info->name) == 0)
         {
             gtk_combo_box_set_active_iter (GTK_COMBO_BOX (combobox), &iter);