[Dapper-Intrepid, Jaunty] security-update: udf: Fix oops when invalid character in filename occurs

[Stefan Bader]

https://bugs.launchpad.net/ubuntu/+source/linux/+bug/321606

This bug is being processed as part of the security updates since it can
be used for DoS. Sending it around for review since it would be required
for Jaunty as well. The patch is not yet upstream but queued for stable.

Stefan