[gvfs] udisks2: Fix crash when mounting encrypted volume

[Ondrej Holy <oholy src gnome org>]

commit fd36dd9e1074a4b69d1f05a2c1e201522a288a83
Author: Ondrej Holy <oholy redhat com>
Date:   Mon Apr 18 13:02:42 2016 +0200

    udisks2: Fix crash when mounting encrypted volume
    
    Code handling external unlocks during mount operation was added by the
    commit beea21e recently. Unfortunately, it may cause crashes due to
    accessing already freed memory, because gvfs_udisks2_volume_monitor_update
    waits for pending dbus messages using udisks_client_settle, thus another
    main context iteration may happen (i.e. mount operation may finish and
    mount data may be freed) before accessing mount data pointer. The mount
    data pointer has to be obtained after gvfs_udisks2_volume_monitor_update
    call in order to fix this crashes.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=765146

 monitor/udisks2/gvfsudisks2volume.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/monitor/udisks2/gvfsudisks2volume.c b/monitor/udisks2/gvfsudisks2volume.c
index 8bb572d..2015339 100644
--- a/monitor/udisks2/gvfsudisks2volume.c
+++ b/monitor/udisks2/gvfsudisks2volume.c
@@ -608,10 +608,11 @@ on_udisks_client_changed (UDisksClient *client,
                           gpointer      user_data)
 {
   GVfsUDisks2Volume *volume = GVFS_UDISKS2_VOLUME (user_data);
-  MountData *data = volume->mount_pending_op;
+  MountData *data;
 
   update_volume_on_event (volume);
 
+  data = volume->mount_pending_op;
   if (data && data->mount_operation_aborted_handler_id && data->encrypted_to_unlock)
     {
       UDisksBlock *cleartext_block;