228 lines
11 KiB
Diff
228 lines
11 KiB
Diff
From 7b83c1dc9645cabadfeb253d7eca427f6a26d10f Mon Sep 17 00:00:00 2001
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From: Iain Lane <iainl@gnome.org>
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Date: Thu, 31 Jan 2019 17:51:52 +0000
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Subject: [PATCH 3/4] session: Don't allow greeter operations on an running
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session
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If a client has a reference to a session that starts running,
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refuse to allow further operations on the session.
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CVE-2019-3825
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---
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daemon/gdm-session.c | 75 ++++++++++++++++++++++++++++++++++++++++++++
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1 file changed, 75 insertions(+)
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diff --git a/daemon/gdm-session.c b/daemon/gdm-session.c
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index f23a83c5e..a8263ba11 100644
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--- a/daemon/gdm-session.c
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+++ b/daemon/gdm-session.c
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@@ -1401,130 +1401,205 @@ gdm_session_handle_client_begin_verification_for_user (GdmDBusUserVerifier *u
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static gboolean
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gdm_session_handle_client_answer_query (GdmDBusUserVerifier *user_verifier_interface,
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GDBusMethodInvocation *invocation,
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const char *service_name,
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const char *answer,
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GdmSession *self)
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{
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gdm_dbus_user_verifier_complete_answer_query (user_verifier_interface,
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invocation);
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gdm_session_answer_query (self, service_name, answer);
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return TRUE;
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}
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static gboolean
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gdm_session_handle_client_cancel (GdmDBusUserVerifier *user_verifier_interface,
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GDBusMethodInvocation *invocation,
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GdmSession *self)
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{
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gdm_dbus_user_verifier_complete_cancel (user_verifier_interface,
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invocation);
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gdm_session_cancel (self);
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return TRUE;
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}
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static gboolean
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gdm_session_handle_client_select_session (GdmDBusGreeter *greeter_interface,
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GDBusMethodInvocation *invocation,
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const char *session,
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GdmSession *self)
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{
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+ if (gdm_session_is_running (self)) {
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+ const char *username;
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+
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+ username = gdm_session_get_username (self);
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+ g_debug ("GdmSession: refusing to select session %s since it's already running (for user %s)",
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+ session,
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+ username);
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+ g_dbus_method_invocation_return_error (invocation,
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+ G_DBUS_ERROR,
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+ G_DBUS_ERROR_INVALID_ARGS,
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+ "Session already running for user %s",
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+ username);
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+ return TRUE;
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+ }
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+
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if (self->priv->greeter_interface != NULL) {
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gdm_dbus_greeter_complete_select_session (greeter_interface,
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invocation);
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}
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gdm_session_select_session (self, session);
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return TRUE;
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}
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static gboolean
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gdm_session_handle_client_select_user (GdmDBusGreeter *greeter_interface,
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GDBusMethodInvocation *invocation,
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const char *username,
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GdmSession *self)
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{
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+ if (gdm_session_is_running (self)) {
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+ const char *session_username;
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+
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+ session_username = gdm_session_get_username (self);
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+ g_debug ("GdmSession: refusing to select user %s, since session (%p) already running (for user %s)",
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+ username,
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+ self,
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+ session_username);
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+ g_dbus_method_invocation_return_error (invocation,
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+ G_DBUS_ERROR,
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+ G_DBUS_ERROR_INVALID_ARGS,
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+ "Session already running for user %s",
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+ session_username);
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+ return TRUE;
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+ }
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+
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if (self->priv->greeter_interface != NULL) {
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gdm_dbus_greeter_complete_select_user (greeter_interface,
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invocation);
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}
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g_debug ("GdmSession: client selected user '%s' on session (%p)", username, self);
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gdm_session_select_user (self, username);
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return TRUE;
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}
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static gboolean
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gdm_session_handle_client_start_session_when_ready (GdmDBusGreeter *greeter_interface,
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GDBusMethodInvocation *invocation,
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const char *service_name,
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gboolean client_is_ready,
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GdmSession *self)
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{
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+ if (gdm_session_is_running (self)) {
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+ const char *username;
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+
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+ username = gdm_session_get_username (self);
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+ g_debug ("GdmSession: refusing to start session (%p), since it's already running (for user %s)",
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+ self,
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+ username);
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+ g_dbus_method_invocation_return_error (invocation,
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+ G_DBUS_ERROR,
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+ G_DBUS_ERROR_INVALID_ARGS,
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+ "Session already running for user %s",
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+ username);
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+ return TRUE;
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+ }
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if (self->priv->greeter_interface != NULL) {
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gdm_dbus_greeter_complete_start_session_when_ready (greeter_interface,
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invocation);
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}
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g_signal_emit (G_OBJECT (self),
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signals [CLIENT_READY_FOR_SESSION_TO_START],
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0,
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service_name,
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client_is_ready);
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return TRUE;
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}
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static gboolean
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gdm_session_handle_get_timed_login_details (GdmDBusGreeter *greeter_interface,
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GDBusMethodInvocation *invocation,
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GdmSession *self)
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{
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+ if (gdm_session_is_running (self)) {
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+ const char *username;
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+
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+ username = gdm_session_get_username (self);
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+ g_debug ("GdmSession: refusing to give timed login details, session (%p) already running (for user %s)",
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+ self,
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+ username);
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+ g_dbus_method_invocation_return_error (invocation,
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+ G_DBUS_ERROR,
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+ G_DBUS_ERROR_INVALID_ARGS,
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+ "Session already running for user %s",
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+ username);
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+ return TRUE;
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+ }
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if (self->priv->greeter_interface != NULL) {
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gdm_dbus_greeter_complete_get_timed_login_details (greeter_interface,
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invocation,
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self->priv->timed_login_username != NULL,
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self->priv->timed_login_username != NULL? self->priv->timed_login_username : "",
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self->priv->timed_login_delay);
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if (self->priv->timed_login_username != NULL) {
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gdm_dbus_greeter_emit_timed_login_requested (self->priv->greeter_interface,
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self->priv->timed_login_username,
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self->priv->timed_login_delay);
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}
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}
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return TRUE;
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}
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static gboolean
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gdm_session_handle_client_begin_auto_login (GdmDBusGreeter *greeter_interface,
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GDBusMethodInvocation *invocation,
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const char *username,
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GdmSession *self)
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{
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+ const char *session_username;
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+
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+ if (gdm_session_is_running (self)) {
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+ session_username = gdm_session_get_username (self);
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+ g_debug ("GdmSession: refusing auto login operation, session (%p) already running for user %s (%s requested)",
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+ self,
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+ session_username,
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+ username);
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+ g_dbus_method_invocation_return_error (invocation,
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+ G_DBUS_ERROR,
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+ G_DBUS_ERROR_INVALID_ARGS,
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+ "Session already owned by user %s",
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+ session_username);
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+ return TRUE;
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+ }
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+
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if (self->priv->greeter_interface != NULL) {
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gdm_dbus_greeter_complete_begin_auto_login (greeter_interface,
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invocation);
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}
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g_debug ("GdmSession: client requesting automatic login for user '%s' on session '%s' (%p)",
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username,
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gdm_session_get_session_id (self),
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self);
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gdm_session_setup_for_user (self, "gdm-autologin", username);
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return TRUE;
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}
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static void
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export_user_verifier_interface (GdmSession *self,
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GDBusConnection *connection)
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{
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GdmDBusUserVerifier *user_verifier_interface;
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user_verifier_interface = GDM_DBUS_USER_VERIFIER (gdm_dbus_user_verifier_skeleton_new ());
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g_object_set_data (G_OBJECT (connection), "gdm-session", self);
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g_signal_connect (user_verifier_interface,
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"handle-enable-extensions",
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G_CALLBACK (gdm_session_handle_client_enable_extensions),
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connection);
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g_signal_connect (user_verifier_interface,
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"handle-begin-verification",
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--
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2.21.0
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