integrate cloud-based crypto containers

[Oliver Kastner <kastner gfz-potsdam de>]

Hello everybody,

I am trying to find a sophisticated way to integrate cloud-based crypto 
containers at user level through gnome/nautilus on a laptop. System is 
opensuse 13.1 w/t gnome 3 and gvfsd.

To include a cloud-based device I follow the common route via
fssh -> losetup -> cryptsetup
which produces a mountable device in /dev. User permissions are 
controlled through appropriate rules in /etc/udev/rules.d. Cryptsetup 
requires sudo at user level, while fssh and losetup can be used by 
regular users a priori.

Running through the chain by hand, the loop device is identified by 
nautilus after losetup and a decrypted block device after crytpsetup, 
named appropriately.

$ gvfs-mount -li
Volume(0): Cloud
  Type: GProxyVolume (GProxyVolumeMonitorUDisks2)
  ids:
   class: 'device'
   unix-device: '/dev/dm-1'
   uuid: '37a6324a-746e-4d8c-a318-******'
  symbolic themed icons:  [drive-removable-media-symbolic] 
[drive-removable-symbolic]  [drive-symbolic]  [drive-removable-media] 
[drive-removable]  [drive]
  can_mount=1
  can_eject=0
  should_automount=0
  sort_key=gvfs.time_detected_usec.1421103071214747

However, it is not possible to gvfs-mount this device as user from 
console: "No volume for device file /dev/dm-1"
To mount the block device from within nautilus, root permissions are 
demanded. Providing these, the device is mounted and usable.

Alternatively, it is possible to place an appropriate /etc/fstab entry 
with user-permission and mount by hand from console. The result in 
nautilus is the same. However, placing the chain fssh -> losetup -> 
cryptsetup -> mount (through fstab) in a script that is executed through 
an alacarte-generated button causes nautilus to show an empty directory.

So here are my questions:
Either:
How to tweak nautilus to allow user-mount of the device (I guess this is 
aquivelent to solve the "No volume for device file /dev/dm-1"-issue)

Or:
How to prevent nautilus from interfering regular mounts through a script

Any help is highly appreciated,
Regards Oliver