LUKS code and new method interface

[David Zeuthen]

On Wed, 2005-07-13 at 21:58 -0500, W. Michael Petullo wrote: 
> I just got the LUKS cryptographic disk backend working with the new
> method interface.  The method interface was the last thing I was waiting
> for and it seems to work well.  David Z., I really like that the parameters
> are read from stdin instead of the environment.  Thanks.

Sweet.

> 
> Anyway, in order to get this stuff to work, do the following:
> 
> 1.  Install the latest version of my luks-tools package[1].  Version 0.0.5
> includes a hal-luks-setup wrapper script.

I was thinking it might make sense to ship this in the hal tarball so
distros only need to ship cryptsetup-luks? I would appreciate that.

> 
> 2.  Install a device information file that describes the interface used:
> 
> <?xml version="1.0" encoding="ISO-8859-1"?> <!-- -*- SGML -*- -->
> 
> <deviceinfo version="0.2">
> 
>   <device>
>     <match key="info.udi" string="/org/freedesktop/Hal/devices/computer">
>       <append key="info.interfaces" type="strlist">org.freedesktop.Hal.Device.Luks</append>
>       <append key="org.freedesktop.Hal.Device.Luks.method_names" type="strlist">Setup</append>
>       <append key="org.freedesktop.Hal.Device.Luks.method_signatures" type="strlist">ss</append>
>       <append key="org.freedesktop.Hal.Device.Luks.method_execpaths" type="strlist">/usr/sbin/hal-luks-setup</append>
>     </match>
>   </device>
> </deviceinfo>

Ah, OK, we can do a little bit better here. Something like

  <device>
    <match key="volume.fsusage" string="crypto">
      <match key="volume.fstype" string="crypto_LUKS"> 
        <append key="info.interfaces" type="strlist">org.freedesktop.Hal.Device.Volume.Crypto</append>
        <append key="org.freedesktop.Hal.Device.Volume.Crypto.method_names" type="strlist">Setup</append>
        <append key="org.freedesktop.Hal.Device.Volume.Crypto.method_signatures" type="strlist">s</append>
        <append key="org.freedesktop.Hal.Device.Volume.Crypto.method_execpaths" type="strlist">/usr/sbin/hal-luks-setup</append>
      </match>
    </match>
  </device>

which should probably go in fdi/policy/10osvendor/15-storage-luks.fdi.

So, this has the following advantages

 1. We don't have to pass the device file since hal-luks-setup can find
    this in the environment as HAL_PROP_VOLUME_DEVICE

 2. If we want to support other crypto types than LUKS the API is the
    same only the script is different, e.g.

  <device>
    <match key="volume.fsusage" string="crypto">
      <match key="volume.fstype" string="crypto_SOMETHINGELSE"> 
        <append key="info.interfaces" type="strlist">org.freedesktop.Hal.Device.Volume.Crypto</append>
        <append key="org.freedesktop.Hal.Device.Luks.method_names" type="strlist">Setup</append>
        <append key="org.freedesktop.Hal.Device.Luks.method_signatures" type="strlist">s</append>
        <append key="org.freedesktop.Hal.Device.Luks.method_execpaths" type="strlist">/usr/sbin/hal-someothercrypt-setup</append>
      </match>
    </match>
  </device>

 3. It's more natural to invoke methods on the object representing the
    crypted volume that at the root computer object (methods/interfaces
    on the computer object are for system-wide things only such as 
    e.g. system suspend)

How about that?

> I still need to add HAL interface support to my gnome-volume-manager
> patch.  Until then, you can simulate the interaction with the following
> command:
> 
> dbus-send --system --print-reply --dest=org.freedesktop.Hal /org/freedesktop/Hal/devices/computer org.freedesktop.Hal.Device.Luks.Setup string:/dev/DEVICE string:PASSWORD
> 
> More information, including the status of this project, is available at [2].

Sweet. Thanks a lot.

Cheers,
David


_______________________________________________
hal mailing list
hal at lists.freedesktop.org
http://lists.freedesktop.org/mailman/listinfo/hal