path: root/0001-manager-allow-multiple-xdmcp-logins-for-the-same-use.patch

From 58f2bb3560f1066d0cda93a749a6d1648e3c3d0c Mon Sep 17 00:00:00 2001
From: Ray Strode <rstrode@redhat.com>
Date: Thu, 20 Dec 2018 14:51:38 -0500
Subject: [PATCH 1/3] manager: allow multiple xdmcp logins for the same user

---
 common/gdm-settings-keys.h |  1 +
 daemon/gdm-manager.c       | 71 ++++++++++++++++++++++++++++----------
 data/gdm.schemas.in        |  5 +++
 3 files changed, 59 insertions(+), 18 deletions(-)

diff --git a/common/gdm-settings-keys.h b/common/gdm-settings-keys.h
index 87685d3c..4b3a1ffe 100644
--- a/common/gdm-settings-keys.h
+++ b/common/gdm-settings-keys.h
@@ -30,37 +30,38 @@ G_BEGIN_DECLS
 #define GDM_KEY_AUTO_LOGIN_ENABLE "daemon/AutomaticLoginEnable"
 #define GDM_KEY_AUTO_LOGIN_USER "daemon/AutomaticLogin"
 #define GDM_KEY_TIMED_LOGIN_ENABLE "daemon/TimedLoginEnable"
 #define GDM_KEY_TIMED_LOGIN_USER "daemon/TimedLogin"
 #define GDM_KEY_TIMED_LOGIN_DELAY "daemon/TimedLoginDelay"
 #define GDM_KEY_INITIAL_SETUP_ENABLE "daemon/InitialSetupEnable"
 #define GDM_KEY_PREFERRED_DISPLAY_SERVER "daemon/PreferredDisplayServer"
 #define GDM_KEY_WAYLAND_ENABLE "daemon/WaylandEnable"
 #define GDM_KEY_XORG_ENABLE "daemon/XorgEnable"
 
 #define GDM_KEY_DEBUG "debug/Enable"
 
 #define GDM_KEY_INCLUDE "greeter/Include"
 #define GDM_KEY_EXCLUDE "greeter/Exclude"
 #define GDM_KEY_INCLUDE_ALL "greeter/IncludeAll"
 
 #define GDM_KEY_DISALLOW_TCP "security/DisallowTCP"
 #define GDM_KEY_ALLOW_REMOTE_AUTOLOGIN "security/AllowRemoteAutoLogin"
 
 #define GDM_KEY_XDMCP_ENABLE "xdmcp/Enable"
 #define GDM_KEY_SHOW_LOCAL_GREETER "xdmcp/ShowLocalGreeter"
 #define GDM_KEY_MAX_PENDING "xdmcp/MaxPending"
 #define GDM_KEY_MAX_SESSIONS "xdmcp/MaxSessions"
 #define GDM_KEY_MAX_WAIT "xdmcp/MaxWait"
 #define GDM_KEY_DISPLAYS_PER_HOST "xdmcp/DisplaysPerHost"
 #define GDM_KEY_UDP_PORT "xdmcp/Port"
 #define GDM_KEY_INDIRECT "xdmcp/HonorIndirect"
 #define GDM_KEY_MAX_WAIT_INDIRECT "xdmcp/MaxWaitIndirect"
 #define GDM_KEY_PING_INTERVAL "xdmcp/PingIntervalSeconds"
 #define GDM_KEY_WILLING "xdmcp/Willing"
+#define GDM_KEY_ALLOW_MULTIPLE_SESSIONS_PER_USER "xdmcp/AllowMultipleSessionsPerUser"
 
 #define GDM_KEY_MULTICAST "chooser/Multicast"
 #define GDM_KEY_MULTICAST_ADDR "chooser/MulticastAddr"
 
 G_END_DECLS
 
 #endif /* _GDM_SETTINGS_KEYS_H */
diff --git a/daemon/gdm-manager.c b/daemon/gdm-manager.c
index e1bc62d7..08c3cc17 100644
--- a/daemon/gdm-manager.c
+++ b/daemon/gdm-manager.c
@@ -566,93 +566,106 @@ get_display_and_details_for_bus_sender (GdmManager       *self,
                 *out_tty = get_tty_for_session_id (session_id, &error);
 
                 if (error != NULL) {
                         g_debug ("GdmManager: Error while retrieving tty for session: %s",
                                  error->message);
                         g_clear_error (&error);
                 }
         }
 
         display = gdm_display_store_find (self->priv->display_store,
                                           lookup_by_session_id,
                                           (gpointer) session_id);
 
 out:
         if (out_display != NULL) {
                 *out_display = display;
         }
 
         g_free (session_id);
 }
 
 static gboolean
 switch_to_compatible_user_session (GdmManager *manager,
                                    GdmSession *session,
                                    gboolean    fail_if_already_switched)
 {
         gboolean    res;
         gboolean    ret;
         const char *username;
         const char *seat_id;
-        const char *ssid_to_activate;
+        const char *ssid_to_activate = NULL;
         GdmSession *existing_session;
 
         ret = FALSE;
 
         username = gdm_session_get_username (session);
         seat_id = gdm_session_get_display_seat_id (session);
 
-        if (!fail_if_already_switched) {
-                session = NULL;
-        }
+        if (!fail_if_already_switched)
+                ssid_to_activate = gdm_session_get_session_id (session);
 
-        existing_session = find_session_for_user_on_seat (manager, username, seat_id, session);
+        if (ssid_to_activate == NULL) {
+                if (!seat_id || !sd_seat_can_multi_session (seat_id)) {
+                        g_debug ("GdmManager: unable to activate existing sessions from login screen unless on seat0");
+                        goto out;
+                }
 
-        if (existing_session != NULL) {
-                ssid_to_activate = gdm_session_get_session_id (existing_session);
-                if (seat_id != NULL) {
-                        res = gdm_activate_session_by_id (manager->priv->connection, seat_id, ssid_to_activate);
-                        if (! res) {
-                                g_debug ("GdmManager: unable to activate session: %s", ssid_to_activate);
-                                goto out;
-                        }
+                if (!fail_if_already_switched) {
+                        session = NULL;
                 }
 
-                res = session_unlock (manager, ssid_to_activate);
-                if (!res) {
-                        /* this isn't fatal */
-                        g_debug ("GdmManager: unable to unlock session: %s", ssid_to_activate);
+                existing_session = find_session_for_user_on_seat (manager, username, seat_id, session);
+
+                if (existing_session != NULL) {
+                        ssid_to_activate = gdm_session_get_session_id (existing_session);
                 }
-        } else {
+        }
+
+        if (ssid_to_activate == NULL) {
                 goto out;
         }
 
+        if (seat_id != NULL) {
+                res = gdm_activate_session_by_id (manager->priv->connection, seat_id, ssid_to_activate);
+                if (! res) {
+                        g_debug ("GdmManager: unable to activate session: %s", ssid_to_activate);
+                        goto out;
+                }
+        }
+
+        res = session_unlock (manager, ssid_to_activate);
+        if (!res) {
+                /* this isn't fatal */
+                g_debug ("GdmManager: unable to unlock session: %s", ssid_to_activate);
+        }
+
         ret = TRUE;
 
  out:
         return ret;
 }
 
 static GdmDisplay *
 get_display_for_user_session (GdmSession *session)
 {
         return g_object_get_data (G_OBJECT (session), "gdm-display");
 }
 
 static GdmSession *
 get_user_session_for_display (GdmDisplay *display)
 {
         if (display == NULL) {
                 return NULL;
         }
 
         return g_object_get_data (G_OBJECT (display), "gdm-user-session");
 }
 
 static gboolean
 add_session_record (GdmManager    *manager,
                     GdmSession    *session,
                     GPid           pid,
                     SessionRecord  record)
 {
         const char *username;
         char *display_name, *hostname, *display_device, *display_seat_id;
@@ -1096,92 +1109,114 @@ open_temporary_reauthentication_channel (GdmManager            *self,
         g_signal_connect (session,
                           "client-disconnected",
                           G_CALLBACK (on_reauthentication_client_disconnected),
                           self);
         g_signal_connect (session,
                           "client-rejected",
                           G_CALLBACK (on_reauthentication_client_rejected),
                           self);
         g_signal_connect (session,
                           "cancelled",
                           G_CALLBACK (on_reauthentication_cancelled),
                           self);
         g_signal_connect (session,
                           "conversation-started",
                           G_CALLBACK (on_reauthentication_conversation_started),
                           self);
         g_signal_connect (session,
                           "conversation-stopped",
                           G_CALLBACK (on_reauthentication_conversation_stopped),
                           self);
         g_signal_connect (session,
                           "verification-complete",
                           G_CALLBACK (on_reauthentication_verification_complete),
                           self);
 
         address = gdm_session_get_server_address (session);
 
         return g_strdup (address);
 }
 
+static gboolean
+remote_users_can_log_in_more_than_once (GdmManager *manager)
+{
+        gboolean enabled;
+
+        enabled = FALSE;
+
+        gdm_settings_direct_get_boolean (GDM_KEY_ALLOW_MULTIPLE_SESSIONS_PER_USER, &enabled);
+
+	g_debug ("GdmDisplay: Remote users allowed to log in more than once: %s", enabled? "yes" : "no");
+
+        return enabled;
+}
+
 static gboolean
 gdm_manager_handle_open_reauthentication_channel (GdmDBusManager        *manager,
                                                   GDBusMethodInvocation *invocation,
                                                   const char            *username)
 {
         GdmManager       *self = GDM_MANAGER (manager);
         const char       *sender;
         GdmDisplay       *display = NULL;
         GdmSession       *session;
         GDBusConnection  *connection;
         char             *seat_id = NULL;
         char             *session_id = NULL;
         GPid              pid = 0;
         uid_t             uid = (uid_t) -1;
         gboolean          is_login_screen = FALSE;
         gboolean          is_remote = FALSE;
 
         g_debug ("GdmManager: trying to open reauthentication channel for user %s", username);
 
         sender = g_dbus_method_invocation_get_sender (invocation);
         connection = g_dbus_method_invocation_get_connection (invocation);
         get_display_and_details_for_bus_sender (self, connection, sender, &display, &seat_id, &session_id, NULL, &pid, &uid, &is_login_screen, &is_remote);
 
         if (session_id == NULL || pid == 0 || uid == (uid_t) -1) {
                 g_dbus_method_invocation_return_error_literal (invocation,
                                                                G_DBUS_ERROR,
                                                                G_DBUS_ERROR_ACCESS_DENIED,
                                                                _("No session available"));
 
                 return TRUE;
         }
 
+        if (is_login_screen && is_remote && remote_users_can_log_in_more_than_once (self)) {
+                g_dbus_method_invocation_return_error_literal (invocation,
+                                                               G_DBUS_ERROR,
+                                                               G_DBUS_ERROR_ACCESS_DENIED,
+                                                               "Login screen creates new sessions for remote connections");
+                return TRUE;
+        }
+
         if (is_login_screen) {
                 g_debug ("GdmManager: looking for login screen session for user %s on seat %s", username, seat_id);
                 session = find_session_for_user_on_seat (self,
                                                          username,
                                                          seat_id,
                                                          NULL);
         } else {
                 g_debug ("GdmManager: looking for user session on display");
                 session = get_user_session_for_display (display);
         }
 
         if (session != NULL && gdm_session_is_running (session)) {
                 gdm_session_start_reauthentication (session, pid, uid);
                 g_hash_table_insert (self->priv->open_reauthentication_requests,
                                      GINT_TO_POINTER (pid),
                                      invocation);
         } else if (is_login_screen) {
                 g_dbus_method_invocation_return_error_literal (invocation,
                                                                G_DBUS_ERROR,
                                                                G_DBUS_ERROR_ACCESS_DENIED,
                                                                "Login screen only allowed to open reauthentication channels for running sessions");
                 return TRUE;
         } else {
                 char *address;
                 address = open_temporary_reauthentication_channel (self,
                                                                    seat_id,
                                                                    session_id,
                                                                    pid,
                                                                    uid,
                                                                    is_remote);
diff --git a/data/gdm.schemas.in b/data/gdm.schemas.in
index a1035f95..929d13d9 100644
--- a/data/gdm.schemas.in
+++ b/data/gdm.schemas.in
@@ -112,33 +112,38 @@
     <schema>
       <key>xdmcp/DisplaysPerHost</key>
       <signature>i</signature>
       <default>1</default>
     </schema>
     <schema>
       <key>xdmcp/Port</key>
       <signature>i</signature>
       <default>177</default>
     </schema>
     <schema>
       <key>xdmcp/HonorIndirect</key>
       <signature>b</signature>
       <default>true</default>
     </schema>
     <schema>
       <key>xdmcp/MaxWaitIndirect</key>
       <signature>i</signature>
       <default>30</default>
     </schema>
     <schema>
       <key>xdmcp/PingIntervalSeconds</key>
       <signature>i</signature>
       <default>0</default>
     </schema>
     <schema>
       <key>xdmcp/Willing</key>
       <signature>s</signature>
       <default>@gdmconfdir@/Xwilling</default>
     </schema>
+    <schema>
+      <key>xdmcp/AllowMultipleSessionsPerUser</key>
+      <signature>b</signature>
+      <default>false</default>
+    </schema>
   </schemalist>
 </gdmschemafile>
 
-- 
2.37.3