Date: Mon, 18 Dec 2006 15:28:30 +0100 From: Pawel Jakub Dawidek <pjd@FreeBSD.org> To: RW <fbsd06@mlists.homeunix.com> Cc: freebsd-geom@freebsd.org Subject: Re: gconcat/gbde DVD encryption problem Message-ID: <20061218142830.GE73800@garage.freebsd.pl> In-Reply-To: <200612181322.13560.fbsd06@mlists.homeunix.com> References: <200612181322.13560.fbsd06@mlists.homeunix.com>
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[-- Attachment #1 --] On Mon, Dec 18, 2006 at 01:22:13PM +0000, RW wrote: > A couple of years ago, I created some DVDs encrypted with gdbe. I used 2 > concatenated, file-backed md devices (to avoid the 2GB dvd file limit) and > burned them to dvd. The resulting DVD was accessed like this: > > ---------------------------------------------------------- > mount /dvdrw > > mdconfig -a -t vnode -f /dvdrw/d1 -u 31 > mdconfig -a -t vnode -f /dvdrw/d2 -u 32 > > gconcat create datadvd /dev/md31 /dev/md32 > > gbde attach /dev/concat/datadvd > > mount -o ro /dev/concat/datadvd.bde /mnt/dvd > ---------------------------------------------------------- > > The technique worked fine in February 2005, with whatever was the latest > release, I haven't used the technique since then until a few days ago, but > now I'm having a problem with FreeBSD 6.1. After the mdconfig I get "WARNING: > opening backing store: /dvdrw/d1 readonly", which I doubt is the problem. The > failure occurs here: > > # gbde attach /dev/concat/datadvd > Enter passphrase: > gbde: Attach to concat/datadvd failed: could not access consumer > > > The same problem exists on a newly created disk, so it probably not > corruption. And if I copy the two file to hard disk it works. It just seems > to be a problem when they are on the DVD. > > Any ideas on how to fix this. I'm not particularly bothered about the existing > disks, but I'd like to create some new ones. The problem is because gbde(4) tries to open provider read-write, which is not possible with CD-ROMs. You can work-around it by doing: (insert 1st CD) # dd if=/dev/acd0 of=/dvdrw/d1 bs=1m (insert 2nd CD) # dd if=/dev/acd0 of=/dvdrw/d2 bs=1m # mdconfig -a -f /dvdrw/d1 -u 31 # mdconfig -a -f /dvdrw/d2 -u 32 # gconcat create datadvd /dev/md31 /dev/md32 # gbde attach /dev/concat/datadvd -- Pawel Jakub Dawidek http://www.wheel.pl pjd@FreeBSD.org http://www.FreeBSD.org FreeBSD committer Am I Evil? Yes, I Am! [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (FreeBSD) iD8DBQFFhqWOForvXbEpPzQRAjSKAJ9Lr0Ps21RpopL2W2FaniNSkRSlUQCggmvL y5Fe2PrPeGvJVBK1Qd9HvZs= =6fyY -----END PGP SIGNATURE-----
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