Hi,

I have a CDRW and DVD player. I want the dvd player to play my music/videos/games and the CDRW will be used for burning cds and opening data cds.

I am not sure if I should use chmod or the chgrp command.

I don't need to change the group or chmod the CDRW as I can mount it since it is working and in my fstab already. I just want to make the DVD player play as a non-root user now.

chgrp cdrom hda

Or

chgrp cdrom0 hda

Or

chmod 666 /dev/hda


What is my best option here??


------- DVD-ROM and CDRW Information --------

hda = DVD
hdb = CDRW

/dev/cdrom = dvd
/dev/cdrom1 = cdrw

ls -l /dev/hdb
brw-rw---- 1 root disk 3, 64 Apr 29 17:27 /dev/hdb

ls -l /dev/hda
brw-rw---- 1 root disk 3, 0 Apr 29 17:27 /dev/hda

ls -l /dev/cdrom
lrwxrwxrwx 1 root root 11 Jul 27 00:34 /dev/cdrom -> /dev/cdrom0

ls -l /dev/cdrom1
lrwxrwxrwx 1 root root 8 Jul 27 00:34 /dev/cdrom1 -> /dev/hdb

--------- FSTAB ---------
/dev/hdb /media/cdrom iso9660 ro,user,noauto 0 0
/dev/hdb /media/cdrom0 iso9660 ro,user,noauto 0 0
/dev/hda /media/cdrom1 iso9660 ro,user,noauto 0 0
/dev/fd0 /media/floppy auto rw,user,noauto 0 0
/dev/hdb /cdrom iso9660 ro,user,noauto 0 0


Thanks

Not quite sure, but I think that the best thing to do would be to make a group (or use the cdrom one, whatever) and assign it to own hda, hdb, cdrom, cdrom0, and cdrom1, and then add all users that you want to be able to play DVDs to that group. Since the aforementioned devices are already group-readable, that should make any user in the assigned group able to play CDs, DVDs, and any other thing that requires low-level device access as opposed to file system access. That should work, and create less of a security hole than setting the player SUID root or whatever. BTW, I personally would use only one group for DVD and CD, but if you would like to use separate groups, go ahead, just follow above steps twice, substituting the proper device and group names where needed.

What are the permissions of /dev/cdrom0 (that's what /dev/cdrom is symlinked to?) if they aren't allowing user read/write then chmod it so it does.

ls -l /dev/cdrom0

lrwxrwxrwx 1 root root 8 Jul 27 08:23 /dev/cdrom0 -> /dev/hda

bump

If I do that, will there be any security issues? According to the Red Hat guide about chmod it will loosen security a little. I was trying to use the chgrp command, but I can't figure out how to do it for both the DVD and the CDRW. So, I think I will just use the chmod command.

woah! i don't think editing the device properties directly is a very good idea. just change the options in /etc/fstab to allow non-root users to mount/umount the device.

How do I do that?

Here's the fstab

/dev/hdb /media/cdrom iso9660 ro,user,noauto 0 0
/dev/hdb /media/cdrom0 iso9660 ro,user,noauto 0 0
/dev/hda /media/cdrom1 iso9660 ro,user,noauto 0 0
/dev/fd0 /media/floppy auto rw,user,noauto 0 0
/dev/hdb /cdrom iso9660 ro,user,noauto 0 0

That's not what I meant....although in any case, you're being a little paranoid when we're talking about a single user home system!

If it was actually to do with fstab then I'd agree with you, but I've encountered this problem before (if I've understood correctly) which is regarding mplayer. MPlayer doesn't mount the device like a normal user would, it accesses it directly. Hence to get my friend's DVD drive to play DVD's in Mplayer we had to first of all change his /dev/dvd symlink to point to the correct drive, and secondly make that drive read and writable by normal users. Now think about this...it's hardly a security concern as it's a DVD-Rom drive...so at the worst someone could hack him and watch his Flintstones collection.....ooooheeerrrrr!!!

i'm just curious.... what is the reason behind giving world write access to the dvd-rom device? shouldn't you just have owner/group/world read&execute?

chgrp cdrom /dev/hdb
chgrp cdrom /dev/cdrom0

chgrp cdrom /dev/hda
chgrp cdrom /dev/cdrom1

Will that work? I am not sure if that will work because then hdb and hda would be in the same group called cdrom ....

No purpose, just habit

will the above situation I posted work?

Thanks

I need some help i have a cd drive in my comp! i knew how to access the cd in it by- mount /cdrom -but since i added a dvd drive and burner and now i have to put a cd in the dvd drive to mount it! cause i dont know how to install the other drives! I know that the hard drive is primary master and the burner is primary slave! and the dvd is secondary master and the cd-drive is secondary slave!
I hope i aint confused anyone to much! anyhelp would be appreciated!




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