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gdm/0001-Introduce-gdm-new-session-tool.patch
Joan Torres Lopez 3fef77ad21 Add starting headless sessions with C tool 
Resolves: RHEL-126603
2025-11-05 19:01:30 +01:00

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73 KiB
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From ad5b372db6d05698cf6c79f4b7fd98e1b03547f7 Mon Sep 17 00:00:00 2001
From: Joan Torres <joantolo@redhat.com>
Date: Thu, 15 May 2025 14:54:34 +0200
Subject: [PATCH 1/8] common: Add find graphical sessions for username
This will be used in the next commits to check if starting a new user
session is allowed or there's already one started.
Part-of: <https://gitlab.gnome.org/GNOME/gdm/-/merge_requests/288>
---
common/gdm-common.c | 91 ++++++++++++++++++++++++++++++++-------------
common/gdm-common.h | 4 ++
2 files changed, 69 insertions(+), 26 deletions(-)
diff --git a/common/gdm-common.c b/common/gdm-common.c
index 4e538a5e2..7263e6d39 100644
--- a/common/gdm-common.c
+++ b/common/gdm-common.c
@@ -960,6 +960,64 @@ _systemd_session_is_active (const char *session_id)
return TRUE;
}
+static gboolean
+find_graphical_sessions (const uid_t uid,
+ char ***out_sessions)
+{
+ g_auto (GStrv) sessions = NULL;
+ g_autoptr (GStrvBuilder) builder = NULL;
+ int n_sessions;
+
+ g_debug ("Finding a graphical session for user %d", uid);
+
+ n_sessions = sd_uid_get_sessions (uid,
+ GDM_SYSTEMD_SESSION_REQUIRE_ONLINE,
+ &sessions);
+ if (n_sessions < 0)
+ return FALSE;
+
+ builder = g_strv_builder_new ();
+
+ for (int i = 0; i < n_sessions; ++i) {
+ g_debug ("Considering session '%s'", sessions[i]);
+
+ if (!_systemd_session_is_graphical (sessions[i]))
+ continue;
+
+ if (!_systemd_session_is_active (sessions[i]))
+ continue;
+
+ g_strv_builder_add (builder, g_strdup (sessions[i]));
+ }
+
+ *out_sessions = g_strv_builder_end (builder);
+
+ return TRUE;
+}
+
+gboolean
+gdm_find_graphical_sessions_for_username (const char *username,
+ char ***sessions,
+ GError **error)
+{
+ struct passwd *pwent;
+
+ gdm_get_pwent_for_name (username, &pwent);
+ if (pwent == NULL) {
+ g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
+ "Couldn't get pw entry for username %s", username);
+ return FALSE;
+ }
+
+ if (!find_graphical_sessions (pwent->pw_uid, sessions)) {
+ g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
+ "Couldn't find sessions for username %s", username);
+ return FALSE;
+ }
+
+ return TRUE;
+}
+
gboolean
gdm_find_display_session (GPid pid,
const uid_t uid,
@@ -968,7 +1026,6 @@ gdm_find_display_session (GPid pid,
{
char *local_session_id = NULL;
g_auto(GStrv) sessions = NULL;
- int n_sessions;
int res;
g_return_val_if_fail (out_session_id != NULL, FALSE);
@@ -993,13 +1050,7 @@ gdm_find_display_session (GPid pid,
pid, strerror (-res));
}
- g_debug ("Finding a graphical session for user %d", uid);
-
- n_sessions = sd_uid_get_sessions (uid,
- GDM_SYSTEMD_SESSION_REQUIRE_ONLINE,
- &sessions);
-
- if (n_sessions < 0) {
+ if (!find_graphical_sessions (uid, &sessions)) {
g_set_error (error,
GDM_COMMON_ERROR,
0,
@@ -1008,23 +1059,7 @@ gdm_find_display_session (GPid pid,
return FALSE;
}
- for (int i = 0; i < n_sessions; ++i) {
- g_debug ("Considering session '%s'", sessions[i]);
-
- if (!_systemd_session_is_graphical (sessions[i]))
- continue;
-
- if (!_systemd_session_is_active (sessions[i]))
- continue;
-
- /*
- * We get the sessions from newest to oldest, so take the last
- * one we find that's good
- */
- local_session_id = sessions[i];
- }
-
- if (local_session_id == NULL) {
+ if (g_strv_length (sessions) == 0) {
g_set_error (error,
GDM_COMMON_ERROR,
0,
@@ -1033,7 +1068,11 @@ gdm_find_display_session (GPid pid,
return FALSE;
}
- *out_session_id = g_strdup (local_session_id);
+ /*
+ * We get the sessions from newest to oldest, so take the last
+ * one we find that's good
+ */
+ *out_session_id = g_strdup (sessions[0]);
return TRUE;
}
diff --git a/common/gdm-common.h b/common/gdm-common.h
index 3e210b87b..641c76f2b 100644
--- a/common/gdm-common.h
+++ b/common/gdm-common.h
@@ -81,6 +81,10 @@ gboolean gdm_get_login_window_session_id (const char *seat_id,
gboolean gdm_goto_login_session (GCancellable *cancellable,
GError **error);
+gboolean gdm_find_graphical_sessions_for_username (const char *username,
+ char ***sessions,
+ GError **error);
+
GPtrArray *gdm_get_script_environment (const char *username,
const char *display_name,
const char *display_hostname,
--
2.51.0
From a3630f535c72fabc1ff0ed5ba72cd2109baed4df Mon Sep 17 00:00:00 2001
From: Joan Torres <joantolo@redhat.com>
Date: Thu, 15 May 2025 16:54:57 +0200
Subject: [PATCH 2/8] display: Add GetSessionId method on its dbus iface
This will be used when creating a new user session to track when it gets
destroyed.
Part-of: <https://gitlab.gnome.org/GNOME/gdm/-/merge_requests/288>
---
daemon/gdm-display.c | 17 +++++++++++++++++
daemon/gdm-display.xml | 3 +++
data/gdm.conf.in | 3 +++
3 files changed, 23 insertions(+)
diff --git a/daemon/gdm-display.c b/daemon/gdm-display.c
index 54e054808..41260cb8a 100644
--- a/daemon/gdm-display.c
+++ b/daemon/gdm-display.c
@@ -1132,6 +1132,21 @@ handle_get_seat_id (GdmDBusDisplay *skeleton,
return TRUE;
}
+static gboolean
+handle_get_session_id (GdmDBusDisplay *skeleton,
+ GDBusMethodInvocation *invocation,
+ GdmDisplay *self)
+{
+ GdmDisplayPrivate *priv = gdm_display_get_instance_private (self);
+
+ gdm_dbus_display_complete_get_session_id (skeleton,
+ invocation,
+ priv->session_id ?
+ priv->session_id : "");
+
+ return TRUE;
+}
+
static gboolean
handle_get_x11_display_name (GdmDBusDisplay *skeleton,
GDBusMethodInvocation *invocation,
@@ -1197,6 +1212,8 @@ register_display (GdmDisplay *self)
G_CALLBACK (handle_get_remote_hostname), self, 0);
g_signal_connect_object (priv->display_skeleton, "handle-get-seat-id",
G_CALLBACK (handle_get_seat_id), self, 0);
+ g_signal_connect_object (priv->display_skeleton, "handle-get-session-id",
+ G_CALLBACK (handle_get_session_id), self, 0);
g_signal_connect_object (priv->display_skeleton, "handle-get-x11-display-name",
G_CALLBACK (handle_get_x11_display_name), self, 0);
g_signal_connect_object (priv->display_skeleton, "handle-is-local",
diff --git a/daemon/gdm-display.xml b/daemon/gdm-display.xml
index 3e9b5d86f..18bd2a8b3 100644
--- a/daemon/gdm-display.xml
+++ b/daemon/gdm-display.xml
@@ -10,6 +10,9 @@
<method name="GetSeatId">
<arg name="filename" direction="out" type="s"/>
</method>
+ <method name="GetSessionId">
+ <arg name="session" direction="out" type="s"/>
+ </method>
<method name="IsInitial">
<arg name="initial" direction="out" type="b"/>
</method>
diff --git a/data/gdm.conf.in b/data/gdm.conf.in
index eda131e02..425143d52 100644
--- a/data/gdm.conf.in
+++ b/data/gdm.conf.in
@@ -56,6 +56,9 @@
<allow send_destination="org.gnome.DisplayManager"
send_interface="org.gnome.DisplayManager.Display"
send_member="GetSeatId"/>
+ <allow send_destination="org.gnome.DisplayManager"
+ send_interface="org.gnome.DisplayManager.Display"
+ send_member="GetSessionId"/>
<allow send_destination="org.gnome.DisplayManager"
send_interface="org.gnome.DisplayManager.Display"
send_member="GetX11DisplayName"/>
--
2.51.0
From 5dbd23f70423a37e4e50647c81bebae3ccb73592 Mon Sep 17 00:00:00 2001
From: Joan Torres <joantolo@redhat.com>
Date: Thu, 15 May 2025 17:03:36 +0200
Subject: [PATCH 3/8] manager: Check all autologin details in the same function
In the next commits autologin will be possible in a different way,
having all checks in the same function is needed for that.
Part-of: <https://gitlab.gnome.org/GNOME/gdm/-/merge_requests/288>
---
daemon/gdm-manager.c | 84 +++++++++++++++-----------------------------
1 file changed, 29 insertions(+), 55 deletions(-)
diff --git a/daemon/gdm-manager.c b/daemon/gdm-manager.c
index e048917..99e451c 100644
--- a/daemon/gdm-manager.c
+++ b/daemon/gdm-manager.c
@@ -1324,45 +1324,38 @@ get_timed_login_details (GdmManager *manager,
}
static gboolean
-get_automatic_login_details (GdmManager *manager,
- char **usernamep)
+get_automatic_login_details (GdmManager *manager,
+ GdmDisplay *display,
+ char **out_username)
{
- gboolean res;
gboolean enabled;
- char *username = NULL;
+ g_autofree char *seat_id = NULL;
+ g_autofree char *username = NULL;
- enabled = FALSE;
- username = NULL;
+ g_object_get (G_OBJECT (display),
+ "seat-id", &seat_id,
+ NULL);
- res = gdm_settings_direct_get_boolean (GDM_KEY_AUTO_LOGIN_ENABLE, &enabled);
- if (res && enabled) {
- res = gdm_settings_direct_get_string (GDM_KEY_AUTO_LOGIN_USER, &username);
- }
+ if (seat_id == NULL || !g_str_equal (seat_id, "seat0"))
+ return FALSE;
- if (enabled && res && username != NULL && username[0] != '\0') {
- goto out;
- }
+ if (manager->did_automatic_login || manager->automatic_login_display != NULL)
+ return FALSE;
- g_free (username);
- username = NULL;
- enabled = FALSE;
+ if (!gdm_settings_direct_get_boolean (GDM_KEY_AUTO_LOGIN_ENABLE, &enabled))
+ return FALSE;
- out:
- if (enabled) {
- g_debug ("GdmDisplay: Got automatic login details for display: %d %s",
- enabled,
- username);
- } else {
- g_debug ("GdmDisplay: Got automatic login details for display: 0");
- }
+ if (!gdm_settings_direct_get_string (GDM_KEY_AUTO_LOGIN_USER, &username))
+ return FALSE;
- if (usernamep != NULL) {
- *usernamep = username;
- } else {
- g_free (username);
- }
+ if (!enabled || username == NULL || username[0] == '\0')
+ return FALSE;
- return enabled;
+ g_debug ("GdmDisplay: Got automatic login details for user: %s", username);
+
+ *out_username = g_steal_pointer (&username);
+
+ return TRUE;
}
static const char *
@@ -1496,25 +1489,12 @@ set_up_session (GdmManager *manager,
ActUserManager *user_manager;
ActUser *user;
gboolean loaded;
- gboolean seat_can_autologin = FALSE, seat_did_autologin = FALSE;
- gboolean autologin_enabled = FALSE;
- g_autofree char *seat_id = NULL;
- char *username = NULL;
-
- g_object_get (G_OBJECT (display), "seat-id", &seat_id, NULL);
+ gboolean autologin_enabled;
+ g_autofree char *username = NULL;
- if (g_strcmp0 (seat_id, "seat0") == 0)
- seat_can_autologin = TRUE;
-
- if (manager->did_automatic_login || manager->automatic_login_display != NULL)
- seat_did_autologin = TRUE;
-
- if (seat_can_autologin && !seat_did_autologin)
- autologin_enabled = get_automatic_login_details (manager, &username);
+ autologin_enabled = get_automatic_login_details (manager, display, &username);
if (!autologin_enabled) {
- g_free (username);
-
#ifdef HAVE_LIBXDMCP
if (GDM_IS_XDMCP_CHOOSER_DISPLAY (display)) {
set_up_chooser_session (manager, display);
@@ -1539,7 +1519,7 @@ set_up_session (GdmManager *manager,
operation = g_new (UsernameLookupOperation, 1);
operation->manager = g_object_ref (manager);
operation->display = g_object_ref (display);
- operation->username = username;
+ operation->username = g_steal_pointer (&username);
g_signal_connect (user,
"notify::is-loaded",
@@ -2367,7 +2347,7 @@ on_session_conversation_started (GdmSession *session,
{
GdmDisplay *display;
gboolean enabled;
- char *username;
+ g_autofree char *username = NULL;
g_debug ("GdmManager: session conversation started for service %s on session", service_name);
@@ -2383,11 +2363,7 @@ on_session_conversation_started (GdmSession *session,
return;
}
- if (!display_is_on_seat0 (display)) {
- return;
- }
-
- enabled = get_automatic_login_details (manager, &username);
+ enabled = get_automatic_login_details (manager, display, &username);
if (! enabled) {
return;
@@ -2398,8 +2374,6 @@ on_session_conversation_started (GdmSession *session,
/* service_name will be "gdm-autologin"
*/
gdm_session_setup_for_user (session, service_name, username);
-
- g_free (username);
}
static void
--
2.51.0
From a61080680aa4206b172de0a0233aced0b41872f0 Mon Sep 17 00:00:00 2001
From: Joan Torres <joantolo@redhat.com>
Date: Thu, 15 May 2025 17:06:30 +0200
Subject: [PATCH 4/8] display: Add "autologin-user" property
This will be used to make it start a user session doing autologin instead of
a starting a greeter session.
Part-of: <https://gitlab.gnome.org/GNOME/gdm/-/merge_requests/288>
---
daemon/gdm-display.c | 28 ++++++++++++++++++++++++++++
daemon/gdm-manager.c | 5 +++++
2 files changed, 33 insertions(+)
diff --git a/daemon/gdm-display.c b/daemon/gdm-display.c
index 41260cb8a..acf9b4076 100644
--- a/daemon/gdm-display.c
+++ b/daemon/gdm-display.c
@@ -70,6 +70,8 @@ typedef struct _GdmDisplayPrivate
int status;
time_t creation_time;
+ char *autologin_user;
+
char *x11_cookie;
gsize x11_cookie_size;
GdmDisplayAccessFile *access_file;
@@ -119,6 +121,7 @@ enum {
PROP_IS_LOCAL,
PROP_LAUNCH_ENVIRONMENT,
PROP_IS_INITIAL,
+ PROP_AUTOLOGIN_USER,
PROP_ALLOW_TIMED_LOGIN,
PROP_HAVE_EXISTING_USER_ACCOUNTS,
PROP_DOING_INITIAL_SETUP,
@@ -872,6 +875,17 @@ _gdm_display_set_is_local (GdmDisplay *self,
priv->is_local = is_local;
}
+static void
+_gdm_display_set_autologin_user (GdmDisplay *self,
+ const char *user)
+{
+ GdmDisplayPrivate *priv;
+
+ priv = gdm_display_get_instance_private (self);
+ g_debug ("GdmDisplay: autologin user: %s", user);
+ g_set_str (&priv->autologin_user, user);
+}
+
static void
_gdm_display_set_session_registered (GdmDisplay *self,
gboolean registered)
@@ -979,6 +993,9 @@ gdm_display_set_property (GObject *object,
case PROP_IS_LOCAL:
_gdm_display_set_is_local (self, g_value_get_boolean (value));
break;
+ case PROP_AUTOLOGIN_USER:
+ _gdm_display_set_autologin_user (self, g_value_get_string (value));
+ break;
case PROP_ALLOW_TIMED_LOGIN:
_gdm_display_set_allow_timed_login (self, g_value_get_boolean (value));
break;
@@ -1051,6 +1068,9 @@ gdm_display_get_property (GObject *object,
case PROP_IS_LOCAL:
g_value_set_boolean (value, priv->is_local);
break;
+ case PROP_AUTOLOGIN_USER:
+ g_value_set_string (value, priv->autologin_user);
+ break;
case PROP_IS_CONNECTED:
#ifdef ENABLE_X11_SUPPORT
g_value_set_boolean (value, priv->xcb_connection != NULL);
@@ -1272,6 +1292,7 @@ gdm_display_dispose (GObject *object)
g_clear_handle_id (&priv->finish_idle_id, g_source_remove);
g_clear_object (&priv->launch_environment);
g_clear_pointer (&priv->supported_session_types, g_strfreev);
+ g_clear_pointer (&priv->autologin_user, g_free);
g_warn_if_fail (priv->status != GDM_DISPLAY_MANAGED);
g_warn_if_fail (priv->user_access_file == NULL);
@@ -1358,6 +1379,13 @@ gdm_display_class_init (GdmDisplayClass *klass)
NULL,
FALSE,
G_PARAM_READWRITE | G_PARAM_CONSTRUCT | G_PARAM_STATIC_STRINGS));
+ g_object_class_install_property (object_class,
+ PROP_AUTOLOGIN_USER,
+ g_param_spec_string ("autologin-user",
+ NULL,
+ NULL,
+ NULL,
+ G_PARAM_READWRITE | G_PARAM_CONSTRUCT | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (object_class,
PROP_ALLOW_TIMED_LOGIN,
g_param_spec_boolean ("allow-timed-login",
diff --git a/daemon/gdm-manager.c b/daemon/gdm-manager.c
index f1d966152..e455dad36 100644
--- a/daemon/gdm-manager.c
+++ b/daemon/gdm-manager.c
@@ -1314,8 +1314,12 @@ get_automatic_login_details (GdmManager *manager,
g_object_get (G_OBJECT (display),
"seat-id", &seat_id,
+ "autologin-user", &username,
NULL);
+ if (username != NULL)
+ goto out;
+
if (seat_id == NULL || !g_str_equal (seat_id, "seat0"))
return FALSE;
@@ -1331,6 +1335,7 @@ get_automatic_login_details (GdmManager *manager,
if (!enabled || username == NULL || username[0] == '\0')
return FALSE;
+out:
g_debug ("GdmDisplay: Got automatic login details for user: %s", username);
*out_username = g_steal_pointer (&username);
--
2.51.0
From 3dfde2fb65cb4fec6aad9cd624608992f21c7080 Mon Sep 17 00:00:00 2001
From: Joan Torres <joantolo@redhat.com>
Date: Thu, 15 May 2025 17:27:07 +0200
Subject: [PATCH 5/8] display-factories: Some small cleanups
- Make the naming style of creator funcs the same.
- Make private local_display_factory_create_display func.
- Remove on remote factory unused display status changed callback.
- Return dbus method invocation enum on dbus handlers.
Part-of: <https://gitlab.gnome.org/GNOME/gdm/-/merge_requests/288>
---
daemon/gdm-local-display-factory.c | 52 +++++++++++++----------------
daemon/gdm-local-display-factory.h | 3 --
daemon/gdm-remote-display-factory.c | 27 +++------------
3 files changed, 29 insertions(+), 53 deletions(-)
diff --git a/daemon/gdm-local-display-factory.c b/daemon/gdm-local-display-factory.c
index 23bc8a585..48c08cfa1 100644
--- a/daemon/gdm-local-display-factory.c
+++ b/daemon/gdm-local-display-factory.c
@@ -395,21 +395,16 @@ store_display (GdmLocalDisplayFactory *factory,
/org/gnome/DisplayManager/Manager \
org.gnome.DisplayManager.Manager.GetDisplays
*/
-gboolean
-gdm_local_display_factory_create_transient_display (GdmLocalDisplayFactory *factory,
- char **id,
- GError **error)
+static gboolean
+gdm_local_display_factory_create_display (GdmLocalDisplayFactory *factory,
+ char **id,
+ GError **error)
{
- gboolean ret;
- GdmDisplay *display = NULL;
- gboolean is_initial = FALSE;
+ gboolean is_initial = FALSE;
+ g_autoptr (GdmDisplay) display = NULL;
g_autofree gchar *preferred_display_server = NULL;
- g_return_val_if_fail (GDM_IS_LOCAL_DISPLAY_FACTORY (factory), FALSE);
-
- ret = FALSE;
-
- g_debug ("GdmLocalDisplayFactory: Creating transient display");
+ g_debug ("GdmLocalDisplayFactory: Creating local display");
preferred_display_server = get_preferred_display_server (factory);
@@ -460,22 +455,23 @@ gdm_local_display_factory_create_transient_display (GdmLocalDisplayFactory *fact
store_display (factory, display);
- if (! gdm_display_manage (display)) {
- display = NULL;
- goto out;
+ if (!gdm_display_manage (display)) {
+ g_set_error_literal (error,
+ GDM_DISPLAY_ERROR,
+ GDM_DISPLAY_ERROR_GENERAL,
+ "Failed managing display");
+ return FALSE;
}
- if (! gdm_display_get_id (display, id, NULL)) {
- display = NULL;
- goto out;
+ if (!gdm_display_get_id (display, id, NULL)) {
+ g_set_error_literal (error,
+ GDM_DISPLAY_ERROR,
+ GDM_DISPLAY_ERROR_GENERAL,
+ "Failed getting display id");
+ return FALSE;
}
- ret = TRUE;
- out:
- /* ref either held by store or not at all */
- g_object_unref (display);
-
- return ret;
+ return TRUE;
}
static void
@@ -1590,16 +1586,16 @@ handle_create_transient_display (GdmDBusLocalDisplayFactory *skeleton,
g_autofree char *id = NULL;
gboolean created;
- created = gdm_local_display_factory_create_transient_display (factory,
- &id,
- &error);
+ created = gdm_local_display_factory_create_display (factory,
+ &id,
+ &error);
if (!created) {
g_dbus_method_invocation_return_gerror (invocation, error);
} else {
gdm_dbus_local_display_factory_complete_create_transient_display (skeleton, invocation, id);
}
- return TRUE;
+ return G_DBUS_METHOD_INVOCATION_HANDLED;
}
static gboolean
diff --git a/daemon/gdm-local-display-factory.h b/daemon/gdm-local-display-factory.h
index 49c7140f9..63da3c69c 100644
--- a/daemon/gdm-local-display-factory.h
+++ b/daemon/gdm-local-display-factory.h
@@ -43,9 +43,6 @@ GQuark gdm_local_display_factory_error_quark (v
GdmLocalDisplayFactory * gdm_local_display_factory_new (GdmDisplayStore *display_store);
-gboolean gdm_local_display_factory_create_transient_display (GdmLocalDisplayFactory *factory,
- char **id,
- GError **error);
G_END_DECLS
#endif /* __GDM_LOCAL_DISPLAY_FACTORY_H */
diff --git a/daemon/gdm-remote-display-factory.c b/daemon/gdm-remote-display-factory.c
index deb6d402b..d3e2afe89 100644
--- a/daemon/gdm-remote-display-factory.c
+++ b/daemon/gdm-remote-display-factory.c
@@ -47,20 +47,11 @@ static gpointer remote_display_factory_object = NULL;
G_DEFINE_TYPE (GdmRemoteDisplayFactory, gdm_remote_display_factory, GDM_TYPE_DISPLAY_FACTORY)
-static void
-on_display_status_changed (GdmDisplay *display,
- GParamSpec *arg1,
- GdmRemoteDisplayFactory *factory)
-{
- g_debug ("GdmRemoteDisplayFactory: remote display status changed: %d",
- gdm_display_get_status (display));
-}
-
static gboolean
-gdm_remote_display_factory_create_remote_display (GdmRemoteDisplayFactory *factory,
- const char *remote_id)
+gdm_remote_display_factory_create_display (GdmRemoteDisplayFactory *factory,
+ const char *remote_id)
{
- GdmDisplay *display = NULL;
+ g_autoptr (GdmDisplay) display = NULL;
GdmDisplayStore *store;
g_debug ("GdmRemoteDisplayFactory: Creating remote display");
@@ -72,17 +63,9 @@ gdm_remote_display_factory_create_remote_display (GdmRemoteDisplayFactory *facto
if (!gdm_display_prepare (display)) {
gdm_display_unmanage (display);
- g_object_unref (display);
return FALSE;
}
- g_signal_connect_after (display,
- "notify::status",
- G_CALLBACK (on_display_status_changed),
- factory);
-
- g_object_unref (display);
-
return TRUE;
}
@@ -92,7 +75,7 @@ handle_create_remote_display (GdmDBusRemoteDisplayFactory *skeleton,
const char *remote_id,
GdmRemoteDisplayFactory *factory)
{
- if (!gdm_remote_display_factory_create_remote_display (factory, remote_id))
+ if (!gdm_remote_display_factory_create_display (factory, remote_id))
g_dbus_method_invocation_return_error_literal (invocation,
G_DBUS_ERROR,
G_DBUS_ERROR_FAILED,
@@ -101,7 +84,7 @@ handle_create_remote_display (GdmDBusRemoteDisplayFactory *skeleton,
gdm_dbus_remote_display_factory_complete_create_remote_display (factory->skeleton,
invocation);
- return TRUE;
+ return G_DBUS_METHOD_INVOCATION_HANDLED;
}
static gboolean
--
2.51.0
From 1cfc7a686510b9fe655586ca891ab389cbeaeffc Mon Sep 17 00:00:00 2001
From: Joan Torres <joantolo@redhat.com>
Date: Thu, 15 May 2025 17:34:20 +0200
Subject: [PATCH 6/8] display-factories: Add <Create/Destroy>UserDisplay on its
dbus ifaces
This allows creating or destroying a graphical user session either locally or
headlessly.
It uses a polkit policy to allow only processes in GDM group to call
these methods.
In next commits the policy rule will be enhanced to only authorize processes
in GDM group running from specific systemd system units.
Part-of: <https://gitlab.gnome.org/GNOME/gdm/-/merge_requests/288>
---
daemon/gdm-display-factory.c | 171 ++++++++++++++++++++++++++
daemon/gdm-display-factory.h | 9 ++
daemon/gdm-local-display-factory.c | 84 +++++++++++++
daemon/gdm-local-display-factory.xml | 6 +
daemon/gdm-remote-display-factory.c | 90 +++++++++++++-
daemon/gdm-remote-display-factory.xml | 6 +
daemon/meson.build | 1 +
data/meson.build | 14 +++
data/org.gnome.displaymanager.policy | 20 +++
data/polkit-gdm.rules.in | 8 ++
meson.build | 1 +
11 files changed, 409 insertions(+), 1 deletion(-)
create mode 100644 data/org.gnome.displaymanager.policy
create mode 100644 data/polkit-gdm.rules.in
diff --git a/daemon/gdm-display-factory.c b/daemon/gdm-display-factory.c
index 8ff40ce..640db4a 100644
--- a/daemon/gdm-display-factory.c
+++ b/daemon/gdm-display-factory.c
@@ -26,14 +26,22 @@
#include <glib.h>
#include <glib/gi18n.h>
#include <glib-object.h>
+#include <polkit/polkit.h>
#include "gdm-display-factory.h"
+#include "gdm-common.h"
#include "gdm-display-store.h"
+#define GDM_DISPLAY_FACTORY_MANAGE_DISPLAYS_POLKIT_ACTION "org.gnome.displaymanager.displayfactory.manage-user-displays"
+
typedef struct _GdmDisplayFactoryPrivate
{
GdmDisplayStore *display_store;
guint purge_displays_id;
+
+ GHashTable *display_creation_users;
+
+ PolkitAuthority *authority;
} GdmDisplayFactoryPrivate;
enum {
@@ -142,6 +150,157 @@ gdm_display_factory_stop (GdmDisplayFactory *factory)
return ret;
}
+static gboolean
+ensure_polkit_authority (GdmDisplayFactory *factory,
+ GError **error)
+{
+ GdmDisplayFactoryPrivate *priv;
+
+ priv = gdm_display_factory_get_instance_private (factory);
+
+ if (priv->authority)
+ return TRUE;
+
+ priv->authority = polkit_authority_get_sync (NULL, error);
+
+ return priv->authority != NULL;
+}
+
+gboolean
+gdm_display_factory_authorize_manage_user_displays (GdmDisplayFactory *factory,
+ GDBusMethodInvocation *invocation,
+ GError **error)
+{
+ g_autoptr (PolkitAuthorizationResult) result = NULL;
+ g_autoptr (PolkitSubject) subject = NULL;
+ g_autoptr (GError) local_error = NULL;
+ const char *action;
+ const char *method;
+ const char *sender;
+ PolkitCheckAuthorizationFlags flags;
+ GdmDisplayFactoryPrivate *priv;
+
+ g_return_val_if_fail (GDM_IS_DISPLAY_FACTORY (factory), FALSE);
+
+ method = g_dbus_method_invocation_get_method_name (invocation);
+ if (g_strcmp0 (method, "CreateUserDisplay") != 0 &&
+ g_strcmp0 (method, "DestroyUserDisplay") != 0)
+ return TRUE;
+
+ if (!ensure_polkit_authority (factory, &local_error)) {
+ g_set_error (error, GDM_DISPLAY_ERROR, GDM_DISPLAY_ERROR_GENERAL,
+ "Error getting polkit authority: %s",
+ local_error->message);
+ return FALSE;
+ }
+
+ priv = gdm_display_factory_get_instance_private (factory);
+
+ sender = g_dbus_method_invocation_get_sender (invocation);
+ subject = polkit_system_bus_name_new (sender);
+ action = GDM_DISPLAY_FACTORY_MANAGE_DISPLAYS_POLKIT_ACTION;
+ flags = POLKIT_CHECK_AUTHORIZATION_FLAGS_ALLOW_USER_INTERACTION;
+ result = polkit_authority_check_authorization_sync (priv->authority,
+ subject, action,
+ NULL, flags, NULL,
+ &local_error);
+ if (!result) {
+ g_set_error (error, GDM_DISPLAY_ERROR, GDM_DISPLAY_ERROR_GENERAL,
+ "Failed to check authorization: %s",
+ local_error->message);
+ return FALSE;
+ }
+
+ if (!polkit_authorization_result_get_is_authorized (result)) {
+ g_set_error (error, GDM_DISPLAY_ERROR, GDM_DISPLAY_ERROR_GENERAL,
+ "Not authorized for action %s", action);
+ return FALSE;
+ }
+
+ return TRUE;
+}
+
+gboolean
+gdm_display_factory_on_user_display_creation (GdmDisplayFactory *factory,
+ const char *user,
+ GError **error)
+{
+ g_auto (GStrv) sessions = NULL;
+ GdmDisplayFactoryPrivate *priv;
+
+ g_return_val_if_fail (GDM_IS_DISPLAY_FACTORY (factory), FALSE);
+
+ priv = gdm_display_factory_get_instance_private (factory);
+
+ if (g_hash_table_lookup (priv->display_creation_users, user) != NULL) {
+ g_set_error (error, GDM_DISPLAY_ERROR, GDM_DISPLAY_ERROR_GENERAL,
+ "A display for user %s has already been created", user);
+ return FALSE;
+ }
+
+ if (!gdm_find_graphical_sessions_for_username (user, &sessions, error))
+ return FALSE;
+
+ if (g_strv_length (sessions) > 0) {
+ g_set_error (error, GDM_DISPLAY_ERROR, GDM_DISPLAY_ERROR_GENERAL,
+ "There's already an opened session for user %s", user);
+ return FALSE;
+ }
+
+ g_hash_table_insert (priv->display_creation_users, g_strdup (user), NULL);
+
+ return TRUE;
+}
+
+gboolean
+gdm_display_factory_on_user_display_destruction (GdmDisplayFactory *factory,
+ const char *user,
+ GError **error)
+{
+ g_auto (GStrv) session_ids = NULL;
+ g_autoptr (GError) local_error = NULL;
+ g_autoptr (GDBusConnection) connection = NULL;
+ GdmDisplayFactoryPrivate *priv;
+ int i;
+
+ g_return_val_if_fail (GDM_IS_DISPLAY_FACTORY (factory), FALSE);
+
+ priv = gdm_display_factory_get_instance_private (factory);
+
+ if (!g_hash_table_remove (priv->display_creation_users, user)) {
+ g_set_error (error, GDM_DISPLAY_ERROR, GDM_DISPLAY_ERROR_GENERAL,
+ "A display for user %s wasn't created", user);
+ return FALSE;
+ }
+
+ if (!gdm_find_graphical_sessions_for_username (user, &session_ids, error))
+ return FALSE;
+
+ if (g_strv_length (session_ids) == 0) {
+ g_set_error (error, GDM_DISPLAY_ERROR, GDM_DISPLAY_ERROR_GENERAL,
+ "There's no display for user %s", user);
+ return FALSE;
+ }
+
+ connection = g_bus_get_sync (G_BUS_TYPE_SYSTEM, NULL, &local_error);
+ if (connection == NULL) {
+ g_set_error (error, GDM_DISPLAY_ERROR, GDM_DISPLAY_ERROR_GENERAL,
+ "Failed getting system bus %s", local_error->message);
+ return FALSE;
+ }
+
+ for (i = 0; session_ids[i] != NULL; i++) {
+ if (!gdm_terminate_session_by_id (connection, NULL, session_ids[i])) {
+ g_set_error (error, GDM_DISPLAY_ERROR, GDM_DISPLAY_ERROR_GENERAL,
+ "Failed to terminate session %s",
+ session_ids[i]);
+ return FALSE;
+ }
+ }
+
+ return TRUE;
+}
+
static void
gdm_display_factory_set_display_store (GdmDisplayFactory *factory,
GdmDisplayStore *display_store)
@@ -219,6 +378,14 @@ gdm_display_factory_class_init (GdmDisplayFactoryClass *klass)
static void
gdm_display_factory_init (GdmDisplayFactory *factory)
{
+ GdmDisplayFactoryPrivate *priv;
+
+ priv = gdm_display_factory_get_instance_private (factory);
+
+ priv->display_creation_users = g_hash_table_new_full (g_str_hash,
+ g_str_equal,
+ (GDestroyNotify) g_free,
+ NULL);
}
static void
@@ -235,7 +402,11 @@ gdm_display_factory_finalize (GObject *object)
g_return_if_fail (priv != NULL);
+ g_clear_pointer (&priv->display_creation_users, g_hash_table_destroy);
+
g_clear_handle_id (&priv->purge_displays_id, g_source_remove);
+ g_clear_object (&priv->authority);
+
G_OBJECT_CLASS (gdm_display_factory_parent_class)->finalize (object);
}
diff --git a/daemon/gdm-display-factory.h b/daemon/gdm-display-factory.h
index b17cb1c..afb2b0a 100644
--- a/daemon/gdm-display-factory.h
+++ b/daemon/gdm-display-factory.h
@@ -53,6 +53,15 @@ gboolean gdm_display_factory_start (GdmDispl
gboolean gdm_display_factory_stop (GdmDisplayFactory *manager);
GdmDisplayStore * gdm_display_factory_get_display_store (GdmDisplayFactory *manager);
void gdm_display_factory_queue_purge_displays (GdmDisplayFactory *manager);
+gboolean gdm_display_factory_authorize_manage_user_displays (GdmDisplayFactory *factory,
+ GDBusMethodInvocation *invocation,
+ GError **error);
+gboolean gdm_display_factory_on_user_display_creation (GdmDisplayFactory *factory,
+ const char *user,
+ GError **error);
+gboolean gdm_display_factory_on_user_display_destruction (GdmDisplayFactory *factory,
+ const char *user,
+ GError **error);
G_END_DECLS
diff --git a/daemon/gdm-local-display-factory.c b/daemon/gdm-local-display-factory.c
index 7fd3db5..2d4f2c0 100644
--- a/daemon/gdm-local-display-factory.c
+++ b/daemon/gdm-local-display-factory.c
@@ -398,6 +398,7 @@ store_display (GdmLocalDisplayFactory *factory,
*/
static gboolean
gdm_local_display_factory_create_display (GdmLocalDisplayFactory *factory,
+ const char *autologin_user,
char **id,
GError **error)
{
@@ -454,6 +455,7 @@ gdm_local_display_factory_create_display (GdmLocalDisplayFactory *factory,
"seat-id", "seat0",
"allow-timed-login", FALSE,
"is-initial", is_initial,
+ "autologin-user", autologin_user,
NULL);
store_display (factory, display);
@@ -1603,6 +1605,7 @@ handle_create_transient_display (GdmDBusLocalDisplayFactory *skeleton,
gboolean created;
created = gdm_local_display_factory_create_display (factory,
+ NULL,
&id,
&error);
if (!created) {
@@ -1614,6 +1617,73 @@ handle_create_transient_display (GdmDBusLocalDisplayFactory *skeleton,
return G_DBUS_METHOD_INVOCATION_HANDLED;
}
+static gboolean
+handle_create_user_display (GdmDBusLocalDisplayFactory *skeleton,
+ GDBusMethodInvocation *invocation,
+ const char *user,
+ GdmLocalDisplayFactory *factory)
+{
+ g_autoptr (GError) error = NULL;
+
+ if (!gdm_display_factory_on_user_display_creation (GDM_DISPLAY_FACTORY (factory),
+ user,
+ &error)) {
+ g_dbus_method_invocation_return_gerror (invocation, error);
+ return G_DBUS_METHOD_INVOCATION_HANDLED;
+ }
+
+ if (!gdm_local_display_factory_create_display (factory,
+ user,
+ NULL,
+ &error)) {
+ g_dbus_method_invocation_return_gerror (invocation, error);
+ return G_DBUS_METHOD_INVOCATION_HANDLED;
+ }
+
+ gdm_dbus_local_display_factory_complete_create_user_display (skeleton,
+ invocation);
+
+ return G_DBUS_METHOD_INVOCATION_HANDLED;
+}
+
+static gboolean
+handle_destroy_user_display (GdmDBusLocalDisplayFactory *skeleton,
+ GDBusMethodInvocation *invocation,
+ const char *user,
+ GdmLocalDisplayFactory *factory)
+{
+ g_autoptr (GError) error = NULL;
+
+ if (!gdm_display_factory_on_user_display_destruction (GDM_DISPLAY_FACTORY (factory),
+ user,
+ &error)) {
+ g_dbus_method_invocation_return_gerror (invocation, error);
+ return G_DBUS_METHOD_INVOCATION_HANDLED;
+ }
+
+ gdm_dbus_local_display_factory_complete_destroy_user_display (skeleton,
+ invocation);
+
+ return G_DBUS_METHOD_INVOCATION_HANDLED;
+}
+
+static gboolean
+on_authorize_method (GdmDBusLocalDisplayFactory *skeleton,
+ GDBusMethodInvocation *invocation,
+ GdmLocalDisplayFactory *factory)
+{
+ g_autoptr (GError) error = NULL;
+
+ if (!gdm_display_factory_authorize_manage_user_displays (GDM_DISPLAY_FACTORY (factory),
+ invocation,
+ &error)) {
+ g_dbus_method_invocation_return_gerror (invocation, error);
+ return FALSE;
+ }
+
+ return TRUE;
+}
+
static gboolean
register_factory (GdmLocalDisplayFactory *factory)
{
@@ -1634,6 +1704,20 @@ register_factory (GdmLocalDisplayFactory *factory)
G_CALLBACK (handle_create_transient_display),
factory);
+ g_signal_connect (factory->skeleton,
+ "handle-create-user-display",
+ G_CALLBACK (handle_create_user_display),
+ factory);
+
+ g_signal_connect (factory->skeleton,
+ "handle-destroy-user-display",
+ G_CALLBACK (handle_destroy_user_display),
+ factory);
+
+ g_signal_connect (factory->skeleton, "g-authorize-method",
+ G_CALLBACK (on_authorize_method),
+ factory);
+
if (!g_dbus_interface_skeleton_export (G_DBUS_INTERFACE_SKELETON (factory->skeleton),
factory->connection,
GDM_LOCAL_DISPLAY_FACTORY_DBUS_PATH,
diff --git a/daemon/gdm-local-display-factory.xml b/daemon/gdm-local-display-factory.xml
index 515d991..2241bc4 100644
--- a/daemon/gdm-local-display-factory.xml
+++ b/daemon/gdm-local-display-factory.xml
@@ -4,5 +4,11 @@
<method name="CreateTransientDisplay">
<arg name="id" direction="out" type="o"/>
</method>
+ <method name="CreateUserDisplay">
+ <arg name="user" direction="in" type="s"/>
+ </method>
+ <method name="DestroyUserDisplay">
+ <arg name="user" direction="in" type="s"/>
+ </method>
</interface>
</node>
diff --git a/daemon/gdm-remote-display-factory.c b/daemon/gdm-remote-display-factory.c
index d3e2afe..7fb50ef 100644
--- a/daemon/gdm-remote-display-factory.c
+++ b/daemon/gdm-remote-display-factory.c
@@ -20,6 +20,7 @@
#include "config.h"
+#include "gdm-common.h"
#include "gdm-remote-display.h"
#include "gdm-remote-display-factory.h"
#include "gdm-remote-display-factory-glue.h"
@@ -49,6 +50,7 @@ G_DEFINE_TYPE (GdmRemoteDisplayFactory, gdm_remote_display_factory, GDM_TYPE_DIS
static gboolean
gdm_remote_display_factory_create_display (GdmRemoteDisplayFactory *factory,
+ const char *autologin_user,
const char *remote_id)
{
g_autoptr (GdmDisplay) display = NULL;
@@ -58,6 +60,10 @@ gdm_remote_display_factory_create_display (GdmRemoteDisplayFactory *factory,
display = gdm_remote_display_new (remote_id);
+ g_object_set (display,
+ "autologin-user", autologin_user,
+ NULL);
+
store = gdm_display_factory_get_display_store (GDM_DISPLAY_FACTORY (factory));
gdm_display_store_add (store, display);
@@ -75,7 +81,7 @@ handle_create_remote_display (GdmDBusRemoteDisplayFactory *skeleton,
const char *remote_id,
GdmRemoteDisplayFactory *factory)
{
- if (!gdm_remote_display_factory_create_display (factory, remote_id))
+ if (!gdm_remote_display_factory_create_display (factory, NULL, remote_id))
g_dbus_method_invocation_return_error_literal (invocation,
G_DBUS_ERROR,
G_DBUS_ERROR_FAILED,
@@ -87,6 +93,74 @@ handle_create_remote_display (GdmDBusRemoteDisplayFactory *skeleton,
return G_DBUS_METHOD_INVOCATION_HANDLED;
}
+static gboolean
+handle_create_user_display (GdmDBusRemoteDisplayFactory *skeleton,
+ GDBusMethodInvocation *invocation,
+ const char *user,
+ GdmRemoteDisplayFactory *factory)
+{
+ g_auto (GStrv) sessions = NULL;
+ g_autoptr (GError) error = NULL;
+
+ if (!gdm_display_factory_on_user_display_creation (GDM_DISPLAY_FACTORY (factory),
+ user,
+ &error)) {
+ g_dbus_method_invocation_return_gerror (invocation, error);
+ return G_DBUS_METHOD_INVOCATION_HANDLED;
+ }
+
+ if (!gdm_remote_display_factory_create_display (factory, user, NULL)) {
+ g_dbus_method_invocation_return_error (invocation,
+ G_DBUS_ERROR,
+ G_DBUS_ERROR_FAILED,
+ "Error creating remote display");
+ return G_DBUS_METHOD_INVOCATION_HANDLED;
+ }
+
+ gdm_dbus_remote_display_factory_complete_create_user_display (factory->skeleton,
+ invocation);
+
+ return G_DBUS_METHOD_INVOCATION_HANDLED;
+}
+
+static gboolean
+handle_destroy_user_display (GdmDBusRemoteDisplayFactory *skeleton,
+ GDBusMethodInvocation *invocation,
+ const char *user,
+ GdmRemoteDisplayFactory *factory)
+{
+ g_autoptr (GError) error = NULL;
+
+ if (!gdm_display_factory_on_user_display_destruction (GDM_DISPLAY_FACTORY (factory),
+ user,
+ &error)) {
+ g_dbus_method_invocation_return_gerror (invocation, error);
+ return G_DBUS_METHOD_INVOCATION_HANDLED;
+ }
+
+ gdm_dbus_remote_display_factory_complete_destroy_user_display (skeleton,
+ invocation);
+
+ return G_DBUS_METHOD_INVOCATION_HANDLED;
+}
+
+static gboolean
+on_authorize_method (GdmDBusRemoteDisplayFactory *skeleton,
+ GDBusMethodInvocation *invocation,
+ GdmRemoteDisplayFactory *factory)
+{
+ g_autoptr (GError) error = NULL;
+
+ if (!gdm_display_factory_authorize_manage_user_displays (GDM_DISPLAY_FACTORY (factory),
+ invocation,
+ &error)) {
+ g_dbus_method_invocation_return_gerror (invocation, error);
+ return FALSE;
+ }
+
+ return TRUE;
+}
+
static gboolean
register_factory (GdmRemoteDisplayFactory *factory)
{
@@ -106,6 +180,20 @@ register_factory (GdmRemoteDisplayFactory *factory)
G_CALLBACK (handle_create_remote_display),
factory);
+ g_signal_connect (factory->skeleton,
+ "handle-create-user-display",
+ G_CALLBACK (handle_create_user_display),
+ factory);
+
+ g_signal_connect (factory->skeleton,
+ "handle-destroy-user-display",
+ G_CALLBACK (handle_destroy_user_display),
+ factory);
+
+ g_signal_connect (factory->skeleton, "g-authorize-method",
+ G_CALLBACK (on_authorize_method),
+ factory);
+
if (!g_dbus_interface_skeleton_export (G_DBUS_INTERFACE_SKELETON (factory->skeleton),
factory->connection,
GDM_REMOTE_DISPLAY_FACTORY_DBUS_PATH,
diff --git a/daemon/gdm-remote-display-factory.xml b/daemon/gdm-remote-display-factory.xml
index 84ce477..27cb9d1 100644
--- a/daemon/gdm-remote-display-factory.xml
+++ b/daemon/gdm-remote-display-factory.xml
@@ -4,5 +4,11 @@
<method name="CreateRemoteDisplay">
<arg name="remote_id" direction="in" type="o"/>
</method>
+ <method name="CreateUserDisplay">
+ <arg name="user" direction="in" type="s"/>
+ </method>
+ <method name="DestroyUserDisplay">
+ <arg name="user" direction="in" type="s"/>
+ </method>
</interface>
</node>
diff --git a/daemon/meson.build b/daemon/meson.build
index 31f9baa..39e93ad 100644
--- a/daemon/meson.build
+++ b/daemon/meson.build
@@ -74,6 +74,7 @@ gdm_daemon_deps = [
gio_unix_dep,
json_glib,
libpam_dep,
+ polkit_dep,
]
if have_x11_support
gdm_daemon_deps += [
diff --git a/data/meson.build b/data/meson.build
index 0653029..06b63e7 100644
--- a/data/meson.build
+++ b/data/meson.build
@@ -223,3 +223,17 @@ if get_option('gdm-xsession') and have_x11_support
install_dir: gdmconfdir,
)
endif
+
+# Polkit
+configure_file(
+ input: 'polkit-gdm.rules.in',
+ output: '20-gdm.rules',
+ configuration: {
+ 'GDM_USERNAME': get_option('user'),
+ },
+ install_dir: get_option('datadir') / 'polkit-1' / 'rules.d',
+)
+install_data(
+ 'org.gnome.displaymanager.policy',
+ install_dir: get_option('datadir') / 'polkit-1' / 'actions',
+)
diff --git a/data/org.gnome.displaymanager.policy b/data/org.gnome.displaymanager.policy
new file mode 100644
index 0000000..e65da39
--- /dev/null
+++ b/data/org.gnome.displaymanager.policy
@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE policyconfig PUBLIC
+ "-//freedesktop//DTD PolicyKit Policy Configuration 1.0//EN"
+ "http://www.freedesktop.org/standards/PolicyKit/1.0/policyconfig.dtd">
+<policyconfig>
+
+ <vendor>The GNOME Project</vendor>
+ <vendor_url>http://www.gnome.org/</vendor_url>
+
+ <action id="org.gnome.displaymanager.displayfactory.manage-user-displays">
+ <description>Allow managing user sessions</description>
+ <message>Authentication is required to start or stop a user session</message>
+ <defaults>
+ <allow_any>auth_admin</allow_any>
+ <allow_inactive>auth_admin</allow_inactive>
+ <allow_active>auth_admin</allow_active>
+ </defaults>
+ </action>
+
+</policyconfig>
diff --git a/data/polkit-gdm.rules.in b/data/polkit-gdm.rules.in
new file mode 100644
index 0000000..c9ef490
--- /dev/null
+++ b/data/polkit-gdm.rules.in
@@ -0,0 +1,8 @@
+polkit.addRule(function(action, subject) {
+ if (subject.user !== "@GDM_USERNAME@")
+ return undefined;
+
+ if (action.id == "org.gnome.displaymanager.displayfactory.manage-user-displays") {
+ return polkit.Result.YES;
+ }
+});
diff --git a/meson.build b/meson.build
index 623ec15..f3896df 100644
--- a/meson.build
+++ b/meson.build
@@ -69,6 +69,7 @@ json_glib = dependency('json-glib-1.0', version: '>= 1.2.0',
accountsservice_dep = dependency('accountsservice', version: '>= 0.6.35')
keyutils_dep = dependency('libkeyutils', required: false)
libselinux_dep = dependency('libselinux', required: get_option('selinux'))
+polkit_dep = dependency('polkit-gobject-1')
# udev
if udev_dir == ''
--
2.51.0
From 812416db531899b85c69626ad9664d849246a47b Mon Sep 17 00:00:00 2001
From: Joan Torres <joantolo@redhat.com>
Date: Thu, 15 May 2025 21:12:20 +0200
Subject: [PATCH 7/8] Introduce gdm-new-session
This daemon/tool allows starting a user session either locally or headlessly.
It communicates with the GDM daemon to start/stop the sessions using
the dbus ifaces RemoteDisplayFactory and LocalDisplayFactory.
It watches the GDM Displays dbus object manager to:
1. Check when a new session is created to ensure it has
successfully started the session for the user.
2. Check when the session is finalized to terminate itself.
When it finds out it has successfully started the session, it stores the
session_id. This allows terminating the session in the case this is
terminated.
Install also a service that allows starting a headless user session:
gnome-headless-session@.service
This provides the same functionality than TigerVNC vncserver@.service:
vncserver@.service allows to start a headless Xvnc session for a user.
There's a conf file that maps a display number and how that display
session should be, its username...
It is started as a system service. e.g. vncserver@:1.service
In the case of gnome-headless-session@.service, there's no conf file.
It is a system service that starts a headless gnome desktop session
for the user passed as the argument. e.g. gnome-headless-session@joan.service
In order to get remote access, it is needed to:
1. Configure gnome-remote-desktop for the user with grdctl --headless ...
2. Enable gnome-remote-desktop-headless.service.
Now the polkit rule to use the dbus methods for create/destroy user
displays is updated and only authorizes processes run from the unit
service gnome-headless-session@.service and for the user passed as the.
argument.
Part-of: <https://gitlab.gnome.org/GNOME/gdm/-/merge_requests/288>
---
daemon/gdm-display-factory.c | 10 +-
data/gnome-headless-session@.service.in | 34 +++
data/meson.build | 10 +
data/polkit-gdm.rules.in | 9 +-
utils/gdm-new-session.c | 293 ++++++++++++++++++++++++
utils/meson.build | 15 ++
6 files changed, 369 insertions(+), 2 deletions(-)
create mode 100644 data/gnome-headless-session@.service.in
create mode 100644 utils/gdm-new-session.c
diff --git a/daemon/gdm-display-factory.c b/daemon/gdm-display-factory.c
index 640db4a..ca05f96 100644
--- a/daemon/gdm-display-factory.c
+++ b/daemon/gdm-display-factory.c
@@ -173,10 +173,13 @@ gdm_display_factory_authorize_manage_user_displays (GdmDisplayFactory *fact
{
g_autoptr (PolkitAuthorizationResult) result = NULL;
g_autoptr (PolkitSubject) subject = NULL;
+ g_autoptr (PolkitDetails) details = NULL;
g_autoptr (GError) local_error = NULL;
+ const char *user = NULL;
const char *action;
const char *method;
const char *sender;
+ GVariant *parameters;
PolkitCheckAuthorizationFlags flags;
GdmDisplayFactoryPrivate *priv;
@@ -196,13 +199,18 @@ gdm_display_factory_authorize_manage_user_displays (GdmDisplayFactory *fact
priv = gdm_display_factory_get_instance_private (factory);
+ parameters = g_dbus_method_invocation_get_parameters (invocation);
+ g_variant_get (parameters, "(s)", &user);
+ details = polkit_details_new ();
+ polkit_details_insert (details, "user", user);
+
sender = g_dbus_method_invocation_get_sender (invocation);
subject = polkit_system_bus_name_new (sender);
action = GDM_DISPLAY_FACTORY_MANAGE_DISPLAYS_POLKIT_ACTION;
flags = POLKIT_CHECK_AUTHORIZATION_FLAGS_ALLOW_USER_INTERACTION;
result = polkit_authority_check_authorization_sync (priv->authority,
subject, action,
- NULL, flags, NULL,
+ details, flags, NULL,
&local_error);
if (!result) {
g_set_error (error, GDM_DISPLAY_ERROR, GDM_DISPLAY_ERROR_GENERAL,
diff --git a/data/gnome-headless-session@.service.in b/data/gnome-headless-session@.service.in
new file mode 100644
index 0000000..77d7f6f
--- /dev/null
+++ b/data/gnome-headless-session@.service.in
@@ -0,0 +1,34 @@
+[Unit]
+Description=GNOME Headless Desktop Session
+Requires=gdm.service
+After=gdm.service
+
+[Service]
+User=@GDM_USERNAME@
+ExecStart=@libexecdir@/gdm-new-session %i --headless
+Restart=on-failure
+
+LockPersonality=yes
+MemoryDenyWriteExecute=yes
+RestrictNamespaces=yes
+RestrictAddressFamilies=AF_UNIX
+RestrictRealtime=yes
+RestrictSUIDSGID=yes
+SystemCallArchitectures=native
+CapabilityBoundingSet=
+ProtectKernelModules=yes
+ProtectKernelLogs=yes
+ProtectKernelTunables=yes
+ProtectClock=yes
+ProtectHostname=yes
+ProtectControlGroups=yes
+ProtectHostname=yes
+ProtectProc=invisible
+PrivateDevices=yes
+PrivateNetwork=yes
+NoNewPrivileges=yes
+SystemCallArchitectures=native
+SystemCallFilter=@system-service
+
+[Install]
+WantedBy=graphical.target
diff --git a/data/meson.build b/data/meson.build
index 06b63e7..af8bcf7 100644
--- a/data/meson.build
+++ b/data/meson.build
@@ -192,6 +192,16 @@ if systemdsystemunitdir != 'no'
install_dir: systemd_systemunitdir,
format: 'cmake'
)
+
+ configure_file(
+ input: 'gnome-headless-session@.service.in',
+ output: '@BASENAME@',
+ configuration: {
+ 'GDM_USERNAME': get_option('user'),
+ 'libexecdir': gdm_prefix / get_option('libexecdir'),
+ },
+ install_dir: systemd_systemunitdir,
+ )
endif
gdm_gnome_session_wanted_targets = []
diff --git a/data/polkit-gdm.rules.in b/data/polkit-gdm.rules.in
index c9ef490..0e2327d 100644
--- a/data/polkit-gdm.rules.in
+++ b/data/polkit-gdm.rules.in
@@ -3,6 +3,13 @@ polkit.addRule(function(action, subject) {
return undefined;
if (action.id == "org.gnome.displaymanager.displayfactory.manage-user-displays") {
- return polkit.Result.YES;
+ const user = action.lookup("user");
+ const system_unit = subject.system_unit;
+
+ if (user && system_unit) {
+ const match = system_unit.match(/^gnome-headless-session@(.+?)\.service$/);
+ if (match && user == match[1])
+ return polkit.Result.YES;
+ }
}
});
diff --git a/utils/gdm-new-session.c b/utils/gdm-new-session.c
new file mode 100644
index 0000000..898ca51
--- /dev/null
+++ b/utils/gdm-new-session.c
@@ -0,0 +1,293 @@
+/*
+ * SPDX-FileCopyrightText: 2025 Joan Torres Lopez <joantolo@redhat.com>
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "config.h"
+
+#include <gio/gio.h>
+#include <glib-unix.h>
+#include <sysexits.h>
+#include <systemd/sd-login.h>
+
+#define GDM_DBUS_NAME "org.gnome.DisplayManager"
+#define GDM_LOCAL_DISPLAY_FACTORY_PATH "/org/gnome/DisplayManager/LocalDisplayFactory"
+#define GDM_REMOTE_DISPLAY_FACTORY_PATH "/org/gnome/DisplayManager/RemoteDisplayFactory"
+#define GDM_DISPLAYS_PATH "/org/gnome/DisplayManager/Displays"
+#define GDM_LOCAL_DISPLAY_FACTORY_INTERFACE "org.gnome.DisplayManager.LocalDisplayFactory"
+#define GDM_REMOTE_DISPLAY_FACTORY_INTERFACE "org.gnome.DisplayManager.RemoteDisplayFactory"
+#define GDM_DISPLAY_INTERFACE "org.gnome.DisplayManager.Display"
+
+typedef struct _State {
+ GMainLoop *event_loop;
+
+ GDBusConnection *connection;
+ GDBusObjectManager *displays;
+
+ char *username;
+ gboolean headless;
+
+ char *display_path;
+
+ gboolean terminate_requested;
+} State;
+
+static gboolean terminate_session (State *state,
+ GError **error);
+
+static void
+state_free (State *state)
+{
+ g_clear_pointer (&state->event_loop, g_main_loop_unref);
+ g_clear_object (&state->connection);
+ g_clear_object (&state->displays);
+ g_clear_pointer (&state->username, g_free);
+ g_clear_pointer (&state->display_path, g_free);
+ g_free (state);
+}
+
+G_DEFINE_AUTOPTR_CLEANUP_FUNC (State, state_free);
+
+static void
+on_display_added (GDBusObjectManager *displays,
+ GDBusObject *display_object,
+ State *state)
+{
+ g_autoptr (GDBusInterface) display_proxy = NULL;
+ g_autoptr (GVariant) reply = NULL;
+ g_autoptr (GError) error = NULL;
+ g_autofree char *session_id = NULL;
+ g_autofree char *username = NULL;
+
+ display_proxy = g_dbus_object_get_interface (display_object, GDM_DISPLAY_INTERFACE);
+ if (display_proxy == NULL) {
+ g_warning ("GDM exported a non Display object on dbus");
+ return;
+ }
+
+ reply = g_dbus_proxy_call_sync (G_DBUS_PROXY (display_proxy),
+ "GetSessionId",
+ NULL,
+ G_DBUS_CALL_FLAGS_NONE,
+ -1,
+ NULL,
+ &error);
+ if (reply == NULL) {
+ g_warning ("Failed getting SessionId: %s", error->message);
+ return;
+ }
+
+ g_variant_get (reply, "(s)", &session_id);
+
+ if (sd_session_get_username (session_id, &username) < 0)
+ return;
+
+ if (g_strcmp0 (state->username, username) == 0) {
+ g_print ("Session started\n");
+
+ g_set_str (&state->display_path, g_dbus_object_get_object_path (display_object));
+
+ g_signal_handlers_disconnect_by_func (displays,
+ G_CALLBACK (on_display_added),
+ state);
+
+ if (state->terminate_requested) {
+ if (!terminate_session (state, &error))
+ g_warning ("Terminating session failed: %s", error->message);
+ }
+ }
+}
+static void
+on_display_removed (GDBusObjectManager *displays,
+ GDBusObject *display_object,
+ State *state)
+{
+ const char *display_path = g_dbus_object_get_object_path (display_object);
+
+ if (g_strcmp0 (state->display_path, display_path) == 0) {
+ g_print ("Session finished\n");
+
+ g_set_str (&state->display_path, NULL);
+ g_main_loop_quit (state->event_loop);
+ }
+}
+
+static gboolean
+watch_displays (State *state,
+ GError **error)
+{
+ g_autoptr (GDBusObjectManager) displays = NULL;
+
+ displays = g_dbus_object_manager_client_new_sync (state->connection,
+ G_DBUS_OBJECT_MANAGER_CLIENT_FLAGS_NONE,
+ GDM_DBUS_NAME,
+ GDM_DISPLAYS_PATH,
+ NULL,
+ NULL,
+ NULL,
+ NULL,
+ error);
+ if (displays == NULL) {
+ g_dbus_error_strip_remote_error (*error);
+ return FALSE;
+ }
+
+ g_signal_connect (displays,
+ "object-added",
+ G_CALLBACK (on_display_added),
+ state);
+
+ g_signal_connect (displays,
+ "object-removed",
+ G_CALLBACK (on_display_removed),
+ state);
+
+ state->displays = g_steal_pointer (&displays);
+
+ return TRUE;
+}
+
+static gboolean
+setup (State *state,
+ GError **error)
+{
+ g_autoptr (GDBusConnection) connection = NULL;
+
+ connection = g_bus_get_sync (G_BUS_TYPE_SYSTEM, NULL, error);
+ if (connection == NULL) {
+ g_dbus_error_strip_remote_error (*error);
+ return FALSE;
+ }
+
+ state->connection = g_steal_pointer (&connection);
+
+ if (!watch_displays (state, error))
+ return FALSE;
+
+ return TRUE;
+}
+
+static gboolean
+call_gdm_display_factory_method (State *state,
+ const char *method,
+ GError **error)
+{
+ GDBusConnection *connection = state->connection;
+ gboolean headless = state->headless;
+ g_autoptr (GVariant) reply = NULL;
+ const char *dbus_path;
+ const char *dbus_iface;
+
+ if (headless) {
+ dbus_path = GDM_REMOTE_DISPLAY_FACTORY_PATH;
+ dbus_iface = GDM_REMOTE_DISPLAY_FACTORY_INTERFACE;
+ } else {
+ dbus_path = GDM_LOCAL_DISPLAY_FACTORY_PATH;
+ dbus_iface = GDM_LOCAL_DISPLAY_FACTORY_INTERFACE;
+ }
+
+ reply = g_dbus_connection_call_sync (connection,
+ GDM_DBUS_NAME,
+ dbus_path,
+ dbus_iface,
+ method,
+ g_variant_new ("(s)", state->username),
+ NULL,
+ G_DBUS_CALL_FLAGS_NONE,
+ -1, NULL, error);
+ if (reply == NULL) {
+ g_dbus_error_strip_remote_error (*error);
+ return FALSE;
+ }
+
+ return TRUE;
+}
+
+static gboolean
+create_session (State *state,
+ GError **error)
+{
+ return call_gdm_display_factory_method (state,
+ "CreateUserDisplay",
+ error);
+}
+
+static gboolean
+terminate_session (State *state,
+ GError **error)
+{
+ return call_gdm_display_factory_method (state,
+ "DestroyUserDisplay",
+ error);
+}
+
+static gboolean
+on_sigterm (State *state)
+{
+ g_autoptr (GError) error = NULL;
+
+ // Got SIGTERM before the session is created,
+ // wait for it to be created and then terminate it
+ if (state->display_path == NULL) {
+ state->terminate_requested = TRUE;
+ return G_SOURCE_REMOVE;
+ }
+
+ if (!terminate_session (state, &error))
+ g_warning ("Terminating session failed: %s", error->message);
+
+ return G_SOURCE_REMOVE;
+}
+
+int
+main (int argc,
+ char *argv[])
+{
+ g_autoptr (GOptionContext) context = NULL;
+ g_autoptr (State) state = NULL;
+ g_autoptr (GError) error = NULL;
+ g_autofree char *username = NULL;
+ gboolean headless = FALSE;
+
+ GOptionEntry entries[] =
+ {
+ { "headless", 'h', 0, G_OPTION_ARG_NONE, &headless, "Run headless session", NULL },
+ { NULL }
+ };
+
+ context = g_option_context_new ("USER - Run a graphical session as a specified user");
+ g_option_context_add_main_entries (context, entries, NULL);
+
+ if (!g_option_context_parse (context, &argc, &argv, &error)) {
+ g_printerr ("Option parsing failed: %s\n", error->message);
+ return EX_USAGE;
+ }
+
+ if (argc < 2) {
+ g_printerr ("Username is required\n");
+ return EX_USAGE;
+ }
+
+ username = g_strdup (argv[1]);
+
+ state = g_new0 (State, 1);
+ state->username = g_steal_pointer (&username);
+ state->event_loop = g_main_loop_new (NULL, FALSE);
+ state->headless = headless;
+
+ if (!setup (state, &error)) {
+ g_printerr ("Failed: %s\n", error->message);
+ return EX_SOFTWARE;
+ }
+
+ if (!create_session (state, &error)) {
+ g_printerr ("Starting session failed: %s\n", error->message);
+ return EX_SOFTWARE;
+ }
+
+ g_unix_signal_add (SIGTERM, (GSourceFunc) on_sigterm, state);
+
+ g_main_loop_run (state->event_loop);
+
+ return EX_OK;
+}
diff --git a/utils/meson.build b/utils/meson.build
index 2cfbd14..a873b9f 100644
--- a/utils/meson.build
+++ b/utils/meson.build
@@ -35,6 +35,21 @@ gdm_auth_config = executable('gdm-config',
install: true,
)
+# gdm-new-session
+gdm_new_session_deps = [
+ glib_dep,
+ gio_dep,
+ logind_dep,
+]
+
+gdm_new_session = executable('gdm-new-session',
+ 'gdm-new-session.c',
+ dependencies: gdm_new_session_deps,
+ include_directories: config_h_dir,
+ install: true,
+ install_dir: get_option('libexecdir'),
+)
+
auth_config_distro_hooks = [
'redhat',
'generic',
--
2.51.0
From d383da48f4ea9a228f21e4da84a50f1be6349153 Mon Sep 17 00:00:00 2001
From: Joan Torres <joantolo@redhat.com>
Date: Sun, 18 May 2025 20:52:35 +0200
Subject: [PATCH 8/8] remote-display: Add SetRemoteId method
Now accessing these created headless user sessions has two different ways:
1. Directly connecting to the gnome-remote-desktop daemon headless
which is connected to that user session, as explained in the
previous commit.
2. Through the remote login. i.e. connecting to the gnome-remote-desktop
system daemon that provides a headless login screen and after
authenticating, get that headless user session.
To make the option 2 work, the system daemon needs to know the remote_id
of the headless display to be able to do the handover from the login
headless display to the user headless display.
This allows the system daemon generate a valid remote_id and assign it to
this new headless display.
Part-of: <https://gitlab.gnome.org/GNOME/gdm/-/merge_requests/288>
---
daemon/gdm-remote-display.c | 18 ++++++++++++++++++
daemon/gdm-remote-display.xml | 3 +++
2 files changed, 21 insertions(+)
diff --git a/daemon/gdm-remote-display.c b/daemon/gdm-remote-display.c
index 83954620f..0d243ff20 100644
--- a/daemon/gdm-remote-display.c
+++ b/daemon/gdm-remote-display.c
@@ -60,6 +60,19 @@ gdm_remote_display_set_remote_id (GdmRemoteDisplay *display,
g_object_set (G_OBJECT (display->skeleton), "remote-id", remote_id, NULL);
}
+static gboolean
+handle_set_remote_id (GdmDBusRemoteDisplay *skeleton,
+ GDBusMethodInvocation *invocation,
+ const char *remote_id,
+ GdmRemoteDisplay *display)
+{
+ g_object_set (G_OBJECT (display->skeleton), "remote-id", remote_id, NULL);
+
+ gdm_dbus_remote_display_complete_set_remote_id (skeleton, invocation);
+
+ return G_DBUS_METHOD_INVOCATION_HANDLED;
+}
+
static GObject *
gdm_remote_display_constructor (GType type,
guint n_construct_properties,
@@ -78,6 +91,11 @@ gdm_remote_display_constructor (GType type,
g_object_bind_property (display, "session-id", display->skeleton, "session-id", G_BINDING_SYNC_CREATE);
+ g_signal_connect (display->skeleton,
+ "handle-set-remote-id",
+ G_CALLBACK (handle_set_remote_id),
+ display);
+
return G_OBJECT (display);
}
diff --git a/daemon/gdm-remote-display.xml b/daemon/gdm-remote-display.xml
index 2fdf9ad7f..4d9542f24 100644
--- a/daemon/gdm-remote-display.xml
+++ b/daemon/gdm-remote-display.xml
@@ -3,5 +3,8 @@
<interface name="org.gnome.DisplayManager.RemoteDisplay">
<property name="RemoteId" type="o" access="read"/>
<property name="SessionId" type="s" access="read"/>
+ <method name="SetRemoteId">
+ <arg name="remote_id" direction="in" type="o"/>
+ </method>
</interface>
</node>
--
2.51.0
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