[vox-tech] Encrypted CDROM

[Michael Wenk]

On Wednesday 03 August 2005 16:51, Richard Harke wrote:
> On Wed August 3 2005 13:03, Michael J Wenk wrote:
> > On Wed, Aug 03, 2005 at 12:44:52PM -0700, Richard Harke wrote:
> > > Using loopback and cryptsetup (which uses the device mapper)
> > > I created an encrypted file system about the size of a CDRom. I put
> > > some files into this file system then I burned a CD using cdrecord.
> > > No error indications so far. Now I want to read the CD to verify
> > > whats on it. When I do a cryptsetup, I get an error. The command is
> > >
> > > cryptsetup create --size=1431552 aname /dev/cdrom
> > >
> > > The error I get is Invalid argument to an ioctl call. The ioctl call
> > > is trying to load the table to the mapper device. I ran strace but
> > > didn't get any more info. I've looked at the source but so far
> > > I haven't figured it out.
> > >
> > > Does any one out there have any ideas?
> > >
> > > Richard Harke
> > > _______________________________________________
> >
> > All I have is a possible workaround.
> >
> > dd if=/dev/cdrom of=tmp.iso bs=64k
> >
> >
> > Then run the cryptsetup on the iso file.
> >
> > More than likely(this is just a stab btw, I am not completely sure of
> > what I am talking about and I am going off of memory of how the ioctl's
> > interface with the driver on linux) what's happening is the ioctl called
> > by the command is not valid with the device in question.  If you make
> > the device into a file and then try it with the file, it *may* work.
> >
> > Mike
>
> That does work. I used dd, then losetup, cryptsetup and finally mount.
> I need to use losetup first because cryptsetup works on a device,
> not a file. As long as I have lots of hard disk space, I guess I could just
> keep the encrypted file-system images on the hard drive and just
> write to CD for backup.
>
> I'm still a little curious though as I know the ioctl was to the just
> created device-mapper device and it certainly needs a table load to
> function.
>
> Richard

What type of device did you use to create the filesystem in the first place? 

Mike

-- 
wenk at praxis.homedns.org
Mike Wenk