Monday, December 22, 2008

CD/DVD burning broken in openSuse 11.1

CD/DVD burning seems to be broken/not working by default in openSuse 11.1 - at least on my PC with a pretty standard 5-years old DVDRW drive from LG. There seems to be a problem with device permissions: the /dev/sr0 device (my DVDRW drive) is owned by root:disk and therefore not accessible for CD burning software (/usr/bin/wodim to be exact) when executed by regular users. Here is a workaround for this problem:
  • make your user a member of "cdrom" group
  • create /etc/udev/rules.d/99-my.rules file with the following entry:
    KERNEL=="sr*[0-9]", GROUP="cdrom", MODE="0660"
  • set setuid bit for /usr/bin/wodim (note: this has some security implications; make sure you understand what it is all about):
    chmod u+s /usr/bin/wodim
  • reboot
Remarks:
  • this assumes your CD/DVD writer is mapped to a /dev/sr* device (should be the case for all drives, but I couldn't verify that).
  • if this rule causes any side-effects to other /dev/sr* devices you may have installed, restrict the rule for specific device instead of using regular expression.
It would be of course possible to make your user a member of "disk" group, but it would be a real security problem, as this would also allow for low level access to hard disks.

Updates:
  • the bug has already been reported on Novell's bugzilla
  • making wodim setuid seems to be not needed after all (udev rule is enough).

2 comments:

William said...

Pawel, Thanks very much for posting this information. I was one of many who reported this "bug" and even filed a formal report on bugzilla ... but it didn't seem to get any traction. It's hard to believe that folks just weren't
burning cd's and dvd's with opensuse 11.1.
Your fix seems to work just fine.
Thanks again.

Pawel Stolowski said...

I'm glad it helped and thanks for confirming it. Yes, this is simply unbelievable they haven't tested such basic functionality... It's even more amazing they haven't released a fix yet given the severity of this issue, number of bug reports and number of affected users. Simply disappointing.