diff --git a/daemon/Makefile.am b/daemon/Makefile.am
index 5e9eb5e..80cce87 100644
--- a/daemon/Makefile.am
+++ b/daemon/Makefile.am
@@ -147,11 +147,13 @@ nodist_gdm_session_worker_SOURCES =		\
 	gdm-session-enum-types.h		\
 	$(NULL)
 
+## We need XLIB_LIBS for Xauth.
 gdm_wayland_session_LDADD =		\
 	$(top_builddir)/common/libgdmcommon.la	\
 	$(GTK_LIBS)		\
 	$(COMMON_LIBS)		\
 	$(SYSTEMD_LIBS)         \
+	$(XLIB_LIBS)		\
 	$(NULL)
 
 gdm_wayland_session_SOURCES =	\
diff --git a/daemon/gdm-wayland-session.c b/daemon/gdm-wayland-session.c
index b648e9d..bfadf9b 100644
--- a/daemon/gdm-wayland-session.c
+++ b/daemon/gdm-wayland-session.c
@@ -36,6 +36,8 @@
 
 #include <gio/gunixinputstream.h>
 
+#include <X11/Xauth.h>
+
 #define BUS_ADDRESS_FILENO (STDERR_FILENO + 1)
 
 typedef struct
@@ -47,6 +49,8 @@ typedef struct
         GDBusConnection *bus_connection;
         char            *bus_address;
 
+        char            *x_auth_file;
+
         char           **environment;
 
         GSubprocess  *session_subprocess;
@@ -58,6 +62,102 @@ typedef struct
         guint32       debug_enabled : 1;
 } State;
 
+static FILE *
+create_auth_file (char **filename)
+{
+        char *auth_dir = NULL;
+        char *auth_file = NULL;
+        int fd;
+        FILE *fp = NULL;
+
+        auth_dir = g_build_filename (g_get_user_runtime_dir (),
+                                     "gdm",
+                                     NULL);
+
+        g_mkdir_with_parents (auth_dir, 0711);
+        auth_file = g_build_filename (auth_dir, "Xauthority", NULL);
+        g_clear_pointer (&auth_dir, g_free);
+
+        fd = g_open (auth_file, O_RDWR | O_CREAT | O_TRUNC, 0700);
+
+        if (fd < 0) {
+                g_debug ("could not open %s to store auth cookie: %m",
+                         auth_file);
+                g_clear_pointer (&auth_file, g_free);
+                goto out;
+        }
+
+        fp = fdopen (fd, "w+");
+
+        if (fp == NULL) {
+                g_debug ("could not set up stream for auth cookie file: %m");
+                g_clear_pointer (&auth_file, g_free);
+                close (fd);
+                goto out;
+        }
+
+        *filename = auth_file;
+out:
+        return fp;
+}
+
+static char *
+prepare_auth_file (void)
+{
+        FILE     *fp = NULL;
+        char     *filename = NULL;
+        GError   *error = NULL;
+        gboolean  prepared = FALSE;
+        Xauth     auth_entry = { 0 };
+        char      localhost[HOST_NAME_MAX + 1] = "";
+
+        g_debug ("Preparing auth file for X server");
+
+        fp = create_auth_file (&filename);
+
+        if (fp == NULL) {
+                return NULL;
+        }
+
+        if (gethostname (localhost, HOST_NAME_MAX) < 0) {
+                strncpy (localhost, "localhost", sizeof (localhost) - 1);
+        }
+
+        auth_entry.family = FamilyLocal;
+        auth_entry.address = localhost;
+        auth_entry.address_length = strlen (auth_entry.address);
+        auth_entry.name = "MIT-MAGIC-COOKIE-1";
+        auth_entry.name_length = strlen (auth_entry.name);
+
+        auth_entry.data_length = 16;
+        auth_entry.data = gdm_generate_random_bytes (auth_entry.data_length, &error);
+
+        if (error != NULL) {
+                goto out;
+        }
+
+        if (!XauWriteAuth (fp, &auth_entry) || fflush (fp) == EOF) {
+                goto out;
+        }
+
+        auth_entry.family = FamilyWild;
+        if (!XauWriteAuth (fp, &auth_entry) || fflush (fp) == EOF) {
+                goto out;
+        }
+
+        prepared = TRUE;
+
+out:
+        g_clear_pointer (&auth_entry.data, g_free);
+        g_clear_pointer (&fp, fclose);
+
+        if (!prepared) {
+                g_clear_pointer (&filename, g_free);
+        }
+
+        return filename;
+}
+
 static void
 on_bus_finished (GSubprocess  *subprocess,
                  GAsyncResult *result,
@@ -333,6 +433,8 @@ spawn_session (State        *state,
                 g_subprocess_launcher_setenv (launcher, "DBUS_SESSION_BUS_ADDRESS", state->bus_address, TRUE);
         }
 
+        g_subprocess_launcher_setenv (launcher, "XAUTHORITY", state->x_auth_file, TRUE);
+
         subprocess = g_subprocess_launcher_spawnv (launcher,
                                                    (const char * const *) argv,
                                                    &error);
@@ -510,6 +612,8 @@ main (int    argc,
 
         g_unix_signal_add (SIGTERM, (GSourceFunc) on_sigterm, state);
 
+        state->x_auth_file = prepare_auth_file ();
+
         ret = spawn_bus (state, state->cancellable);
 
         if (!ret) {