Comment 21 for bug 10550

(In reply to comment #20)
> One thing worth noting is that in the default setup for Ubuntu, file permissions
> won't prevent the user from reading data off the disc, since the first user is
> added to the "cdrom" group, who has read/write permissions to the block device.
> So file permissions won't provide any real security in this case.

Yes, but that isn't the only function of file ownership and permissions. For
example, if the disc contained a system backup, the ownership and permissions
should be exposed so that if the user restores a directory, it is restored
intact. The permissions might also grant read privileges for other users on the
system (not in the cdrom group).