daemon: don't require seat to locate reauth channel

With systemd, XDMCP sessions don't have associated seats.
Currently, reauth channels find the session by first looking up
the seat, which means unlocking fails for XDMCP.

This commit changes the code to determine session strictly from pid.

https://bugzilla.gnome.org/show_bug.cgi?id=690926

1 files changed, 61 insertions, 442 deletions

diff --git a/daemon/gdm-manager.c b/daemon/gdm-manager.c
index f2c00eda..ad0ac63f 100644
--- a/daemon/gdm-manager.c
+++ b/daemon/gdm-manager.c
@@ -253,251 +253,6 @@ get_uid_for_session_id (GDBusConnection  *connection,
         return FALSE;
 }
 
-#ifdef WITH_SYSTEMD
-static char *
-get_session_id_for_user_on_seat_systemd (const char  *username,
-                                         const char  *seat,
-                                         GError     **error)
-{
-        struct passwd  *pwent;
-        uid_t           uid;
-        int             i;
-        char          **sessions;
-        char           *session = NULL;
-        int             ret;
-
-        pwent = NULL;
-        gdm_get_pwent_for_name (username, &pwent);
-
-        if (pwent == NULL) {
-                g_set_error (error,
-                             G_DBUS_ERROR,
-                             G_DBUS_ERROR_ACCESS_DENIED,
-                             _("Unable to look up UID of user %s"),
-                             username);
-                return NULL;
-        }
-
-        uid = pwent->pw_uid;
-
-        session = NULL;
-        ret = sd_seat_get_sessions (seat, &sessions, NULL, NULL);
-        if (ret < 0 || sessions == NULL) {
-                g_set_error (error,
-                             G_DBUS_ERROR,
-                             G_DBUS_ERROR_ACCESS_DENIED,
-                             "Error getting session ids from systemd: %s",
-                             ret < 0? g_strerror (-ret) : _("no sessions available"));
-                return NULL;
-        }
-
-        for (i = 0; sessions[i] != NULL; i++) {
-                char     *type;
-                char     *state;
-                gboolean  is_closing;
-                gboolean  is_x11;
-                uid_t     session_uid;
-
-                ret = sd_session_get_uid (sessions[i], &session_uid);
-
-                if (ret < 0) {
-                        g_warning ("GdmManager: could not fetch uid of session '%s': %s",
-                                   sessions[i], strerror (-ret));
-                        continue;
-                }
-
-                if (uid != session_uid) {
-                        continue;
-                }
-
-                ret = sd_session_get_type (sessions[i], &type);
-
-                if (ret < 0) {
-                        g_warning ("GdmManager: could not fetch type of session '%s': %s",
-                                   sessions[i], strerror (-ret));
-                        continue;
-                }
-
-                is_x11 = g_strcmp0 (type, "x11") == 0;
-                free (type);
-
-                if (!is_x11) {
-                        continue;
-                }
-
-                ret = sd_session_get_state (sessions[i], &state);
-                if (ret < 0) {
-                        g_warning ("GdmManager: could not fetch state of session '%s': %s",
-                                   sessions[i], strerror (-ret));
-                        continue;
-                }
-
-                is_closing = g_strcmp0 (state, "closing") == 0;
-
-                if (is_closing) {
-                        continue;
-                }
-
-                session = g_strdup (sessions[i]);
-                break;
-
-        }
-
-        if (session == NULL) {
-                g_debug ("GdmManager: There are no applicable sessions (%d looked at)", i);
-                g_set_error (error,
-                             G_DBUS_ERROR,
-                             G_DBUS_ERROR_ACCESS_DENIED,
-                             _("No sessions for %s available for reauthentication"),
-                             username);
-                return NULL;
-        }
-
-        g_debug ("GdmManager: session %s is available for reauthentication", session);
-
-        return session;
-}
-#endif
-
-#ifdef WITH_CONSOLE_KIT
-static char *
-get_session_id_for_user_on_seat_consolekit (GDBusConnection  *connection,
-                                            const char       *username,
-                                            const char       *seat,
-                                            GError          **error)
-{
-        GVariant       *reply;
-        const gchar   **sessions;
-        char           *session = NULL;
-        struct passwd  *pwent;
-        uid_t           uid;
-        int             i;
-
-        pwent = NULL;
-        gdm_get_pwent_for_name (username, &pwent);
-
-        if (pwent == NULL) {
-                g_set_error (error,
-                             G_DBUS_ERROR,
-                             G_DBUS_ERROR_ACCESS_DENIED,
-                             _("Unable to look up UID of user %s"),
-                             username);
-                return NULL;
-        }
-
-        uid = pwent->pw_uid;
-
-        reply = g_dbus_connection_call_sync (connection,
-                                             "org.freedesktop.ConsoleKit",
-                                             "/org/freedesktop/ConsoleKit/Manager",
-                                             "org.freedesktop.ConsoleKit.Manager",
-                                             "GetSessionsForUnixUser",
-                                             g_variant_new ("(u)", (guint32) uid),
-                                             G_VARIANT_TYPE ("(ao)"),
-                                             G_DBUS_CALL_FLAGS_NONE,
-                                             -1,
-                                             NULL,
-                                             error);
-        if (reply == NULL) {
-                g_set_error (error,
-                             G_DBUS_ERROR,
-                             G_DBUS_ERROR_ACCESS_DENIED,
-                             _("Unable to find session for user %s"),
-                             username);
-                return NULL;
-        }
-
-        g_variant_get_child (reply, 0, "^a&o", &sessions);
-        for (i = 0; sessions[i] != NULL; i++) {
-                GVariant *reply2;
-                GError   *error2 = NULL;
-                gchar    *display;
-                gchar    *session_seat_id;
-
-                reply2 = g_dbus_connection_call_sync (connection,
-                                                     "org.freedesktop.ConsoleKit",
-                                                     sessions[i],
-                                                     "org.freedesktop.ConsoleKit.Session",
-                                                     "GetSeatId",
-                                                     NULL,
-                                                     G_VARIANT_TYPE ("(o)"),
-                                                     G_DBUS_CALL_FLAGS_NONE,
-                                                     -1,
-                                                     NULL,
-                                                     &error2);
-                if (reply2 == NULL) {
-                        continue;
-                }
-
-                g_variant_get (reply2, "(o)", &session_seat_id);
-                g_variant_unref (reply2);
-
-                if (g_strcmp0 (seat, session_seat_id) != 0) {
-                        g_free (session_seat_id);
-                        continue;
-                }
-                g_free (session_seat_id);
-
-                reply2 = g_dbus_connection_call_sync (connection,
-                                                     "org.freedesktop.ConsoleKit",
-                                                     sessions[i],
-                                                     "org.freedesktop.ConsoleKit.Session",
-                                                     "GetX11DisplayDevice",
-                                                     NULL,
-                                                     G_VARIANT_TYPE ("(s)"),
-                                                     G_DBUS_CALL_FLAGS_NONE,
-                                                     -1,
-                                                     NULL,
-                                                     &error2);
-                if (reply2 == NULL) {
-                        continue;
-                }
-
-                g_variant_get (reply2, "(s)", &display);
-                g_variant_unref (reply2);
-
-                if (display[0] == '\0') {
-                        g_free (display);
-                        continue;
-                }
-
-                session = g_strdup (sessions[i]);
-                break;
-
-        }
-        g_free (sessions);
-        g_variant_unref (reply);
-
-        if (session == NULL) {
-                g_set_error (error,
-                             G_DBUS_ERROR,
-                             G_DBUS_ERROR_ACCESS_DENIED,
-                             _("Unable to find appropriate session for user %s"),
-                             username);
-        }
-        return session;
-}
-#endif
-
-static char *
-get_session_id_for_user_on_seat (GDBusConnection  *connection,
-                                 const char       *username,
-                                 const char       *seat,
-                                 GError          **error)
-{
-#ifdef WITH_SYSTEMD
-        if (LOGIND_RUNNING()) {
-                return get_session_id_for_user_on_seat_systemd (username, seat, error);
-        }
-#endif
-
-#ifdef WITH_CONSOLE_KIT
-        return get_session_id_for_user_on_seat_consolekit (connection, username, seat, error);
-#endif
-
-        return NULL;
-}
-
 static gboolean
 lookup_by_session_id (const char *id,
                       GdmDisplay *display,
@@ -516,100 +271,73 @@ lookup_by_session_id (const char *id,
         return res;
 }
 
-#ifdef WITH_SYSTEMD
-static char *
-get_seat_id_for_pid_systemd (pid_t    pid,
-                             GError **error)
+static GdmDisplay *
+get_display_and_details_for_bus_sender (GdmManager       *self,
+                            GDBusConnection  *connection,
+                            const char       *sender,
+                            GPid             *out_pid,
+                            uid_t            *out_uid)
 {
-        char *session;
-        char *seat, *gseat;
-        int ret;
+        GdmDisplay *display = NULL;
+        char       *session_id = NULL;
+        GError     *error = NULL;
+        int         ret;
+        GPid        pid;
+        uid_t       caller_uid, session_uid;
 
-        session = get_session_id_for_pid_systemd (pid, error);
+        ret = gdm_dbus_get_pid_for_name (sender, &pid, &error);
 
-        if (session == NULL) {
-                return NULL;
+        if (!ret) {
+                g_debug ("GdmManager: Error while retrieving pid for sender: %s",
+                         error->message);
+                g_error_free (error);
+                goto out;
         }
 
-        seat = NULL;
-        ret = sd_session_get_seat (session, &seat);
-        free (session);
+        ret = gdm_dbus_get_uid_for_name (sender, &caller_uid, &error);
 
-        if (ret < 0) {
-                g_set_error (error,
-                             GDM_DISPLAY_ERROR,
-                             GDM_DISPLAY_ERROR_GETTING_SESSION_INFO,
-                             "Error getting seat id from systemd: %s",
-                             g_strerror (-ret));
-                return NULL;
+        if (!ret) {
+                g_debug ("GdmManager: Error while retrieving uid for sender: %s",
+                         error->message);
+                g_error_free (error);
+                goto out;
         }
 
-        if (seat != NULL) {
-                gseat = g_strdup (seat);
-                free (seat);
+        session_id = get_session_id_for_pid (connection, pid, &error);
 
-                return gseat;
-        } else {
-                return NULL;
+        if (session_id == NULL) {
+                g_debug ("GdmManager: Error while retrieving session id for sender: %s",
+                         error->message);
+                g_error_free (error);
+                goto out;
         }
-}
-#endif
-
-#ifdef WITH_CONSOLE_KIT
-static char *
-get_seat_id_for_pid_consolekit (GDBusConnection  *connection,
-                                pid_t             pid,
-                                GError          **error)
-{
-        char *session;
-        GVariant *reply;
-        char *retval;
 
-        session = get_session_id_for_pid_consolekit (connection, pid, error);
-
-        if (session == NULL) {
-                return NULL;
+        if (!get_uid_for_session_id (connection, session_id, &session_uid, &error)) {
+                g_debug ("GdmManager: Error while retrieving uid for session: %s",
+                         error->message);
+                g_error_free (error);
+                goto out;
         }
 
-        reply = g_dbus_connection_call_sync (connection,
-                                             "org.freedesktop.ConsoleKit",
-                                             session,
-                                             "org.freedesktop.ConsoleKit.Session",
-                                             "GetSeatId",
-                                             NULL,
-                                             G_VARIANT_TYPE ("(o)"),
-                                             G_DBUS_CALL_FLAGS_NONE,
-                                             -1,
-                                             NULL, error);
-        g_free (session);
-
-        if (reply == NULL) {
-                return NULL;
+        if (caller_uid != session_uid) {
+                g_debug ("GdmManager: uid for sender and uid for session don't match");
+                goto out;
         }
 
-        g_variant_get (reply, "(o)", &retval);
-        g_variant_unref (reply);
+        display = gdm_display_store_find (self->priv->display_store,
+                                          lookup_by_session_id,
+                                          (gpointer) session_id);
+out:
+        g_free (session_id);
 
-        return retval;
-}
-#endif
+        if (display != NULL) {
+            if (out_pid != NULL)
+                *out_pid = pid;
 
-static char *
-get_seat_id_for_pid (GDBusConnection  *connection,
-                     pid_t             pid,
-                     GError          **error)
-{
-#ifdef WITH_SYSTEMD
-        if (LOGIND_RUNNING()) {
-                return get_seat_id_for_pid_systemd (pid, error);
+            if (out_uid != NULL)
+                *out_uid = session_uid;
         }
-#endif
-
-#ifdef WITH_CONSOLE_KIT
-        return get_seat_id_for_pid_consolekit (connection, pid, error);
-#endif
-
-        return NULL;
+        return display;
 }
 
 static gboolean
@@ -617,64 +345,19 @@ gdm_manager_handle_open_session (GdmDBusManager        *manager,
                                  GDBusMethodInvocation *invocation)
 {
         GdmManager       *self = GDM_MANAGER (manager);
+        const char       *sender = NULL;
+        GError           *error = NULL;
         GDBusConnection  *connection;
         GdmDisplay       *display;
-        const char       *sender;
-        char             *session_id;
-        GError           *error;
         char             *address;
-        int               ret;
         GPid              pid;
-        uid_t             caller_uid, session_uid;
+        uid_t             uid;
 
-        sender = g_dbus_method_invocation_get_sender (invocation);
-        error = NULL;
-        ret = gdm_dbus_get_pid_for_name (sender, &pid, &error);
-
-        if (!ret) {
-                g_prefix_error (&error, "Error while retrieving caller session id: ");
-                g_dbus_method_invocation_return_gerror (invocation, error);
-                g_error_free (error);
-                return TRUE;
-        }
-
-        ret = gdm_dbus_get_uid_for_name (sender, &caller_uid, &error);
-
-        if (!ret) {
-                g_prefix_error (&error, "Error while retrieving caller session id: ");
-                g_dbus_method_invocation_return_gerror (invocation, error);
-                g_error_free (error);
-                return TRUE;
-        }
+        g_debug ("GdmManager: trying to open new session");
 
+        sender = g_dbus_method_invocation_get_sender (invocation);
         connection = g_dbus_method_invocation_get_connection (invocation);
-        session_id = get_session_id_for_pid (connection, pid, &error);
-
-        if (session_id == NULL) {
-                g_dbus_method_invocation_return_gerror (invocation, error);
-                g_error_free (error);
-                return TRUE;
-        }
-
-        if (!get_uid_for_session_id (connection, session_id, &session_uid, &error)) {
-                g_prefix_error (&error, "Error while retrieving caller session id: ");
-                g_dbus_method_invocation_return_gerror (invocation, error);
-                g_error_free (error);
-                return TRUE;
-        }
-
-        if (caller_uid != session_uid) {
-                g_dbus_method_invocation_return_error_literal (invocation,
-                                                               G_DBUS_ERROR,
-                                                               G_DBUS_ERROR_ACCESS_DENIED,
-                                                               _("User doesn't own session"));
-                return TRUE;
-        }
-
-        display = gdm_display_store_find (self->priv->display_store,
-                                          lookup_by_session_id,
-                                          (gpointer) session_id);
-        g_free (session_id);
+        display = get_display_and_details_for_bus_sender (self, connection, sender, &pid, &uid);
 
         if (display == NULL) {
                 g_dbus_method_invocation_return_error_literal (invocation,
@@ -685,7 +368,7 @@ gdm_manager_handle_open_session (GdmDBusManager        *manager,
                 return TRUE;
         }
 
-        address = gdm_display_open_session_sync (display, pid, session_uid, NULL, &error);
+        address = gdm_display_open_session_sync (display, pid, uid, NULL, &error);
 
         if (address == NULL) {
                 g_dbus_method_invocation_return_gerror (invocation, error);
@@ -707,83 +390,19 @@ gdm_manager_handle_open_reauthentication_channel (GdmDBusManager        *manager
                                                   const char            *username)
 {
         GdmManager       *self = GDM_MANAGER (manager);
+        const char       *sender = NULL;
+        GError           *error = NULL;
         GDBusConnection  *connection;
         GdmDisplay       *display;
-        const char       *sender;
-        char             *seat_id;
-        char             *session_id = NULL;
-        GError           *error;
         char             *address;
-        int               ret;
         GPid              pid;
-        uid_t             caller_uid;
+        uid_t             uid;
 
         g_debug ("GdmManager: trying to open reauthentication channel for user %s", username);
 
         sender = g_dbus_method_invocation_get_sender (invocation);
-        error = NULL;
-        ret = gdm_dbus_get_pid_for_name (sender, &pid, &error);
-
-        if (!ret) {
-                g_debug ("GdmManager: could not get pid of caller: %s",
-                         error->message);
-                g_error_free (error);
-
-                g_dbus_method_invocation_return_error_literal (invocation,
-                                                               G_DBUS_ERROR,
-                                                               G_DBUS_ERROR_ACCESS_DENIED,
-                                                               "Error getting process id of caller");
-                return TRUE;
-
-        }
-
-        ret = gdm_dbus_get_uid_for_name (sender, &caller_uid, &error);
-
-        if (!ret) {
-                g_debug ("GdmManager: could not get uid of caller: %s",
-                         error->message);
-                g_error_free (error);
-
-                g_dbus_method_invocation_return_error_literal (invocation,
-                                                               G_DBUS_ERROR,
-                                                               G_DBUS_ERROR_ACCESS_DENIED,
-                                                               "Error getting user id of caller");
-                return TRUE;
-        }
-
         connection = g_dbus_method_invocation_get_connection (invocation);
-
-        seat_id = get_seat_id_for_pid (connection, pid, &error);
-
-        if (seat_id == NULL) {
-                g_debug ("GdmManager: could not get seat id of caller: %s",
-                         error->message);
-                g_error_free (error);
-
-                g_dbus_method_invocation_return_error_literal (invocation,
-                                                               G_DBUS_ERROR,
-                                                               G_DBUS_ERROR_ACCESS_DENIED,
-                                                               "Error getting seat id of caller");
-                return TRUE;
-        }
-
-        session_id = get_session_id_for_user_on_seat (connection, username, seat_id, &error);
-        if (session_id == NULL) {
-                g_debug ("GdmManager: could not get session id for caller: %s",
-                         error->message);
-                g_error_free (error);
-
-                g_dbus_method_invocation_return_error_literal (invocation,
-                                                               G_DBUS_ERROR,
-                                                               G_DBUS_ERROR_ACCESS_DENIED,
-                                                               "Error getting session id for caller");
-                return TRUE;
-        }
-
-        display = gdm_display_store_find (self->priv->display_store,
-                                          lookup_by_session_id,
-                                          (gpointer) session_id);
-        g_free (session_id);
+        display = get_display_and_details_for_bus_sender (self, connection, sender, &pid, &uid);
 
         if (display == NULL) {
                 g_dbus_method_invocation_return_error_literal (invocation,
@@ -797,7 +416,7 @@ gdm_manager_handle_open_reauthentication_channel (GdmDBusManager        *manager
         address = gdm_display_open_reauthentication_channel_sync (display,
                                                                   username,
                                                                   pid,
-                                                                  caller_uid,
+                                                                  uid,
                                                                   NULL,
                                                                   &error);