cdrom Mounted but Non Root User Can't Read

tortle · 12-09-2004, 11:37 AM

Hello:

Title summarizes the problem. The cd-rom is mounted:

Code:

root@myhost:~# ls -l /mnt/cdrom/
total 90
-rwxr--r--   1 root root    36 1999-01-06 18:53 file1*
-rwxr--r--   1 root root   156 1999-01-06 18:53 file2*
...

But a non-root user can't read from it:

Code:

user1@myhost:~$ ls -l /mnt/cdrom/
/usr/bin/ls: /mnt/cdrom/file1: Permission denied
/usr/bin/ls: /mnt/cdrom/chars: Permission denied
...

Obviously this is a permissions problem. Right? But:

Code:

 root@myhost:~# ls -ld /mnt/
drwxr-xr-x  5 root root 120 2002-03-16 01:34 /mnt//

root@myhost:~# ls -ld /mnt/cdrom/
drwxr--r--  17 root root 26 1999-02-20 14:11 /mnt/cdrom//

root@myhost:~# ls -ld /mnt/cdrom/*
-rwxr--r--   1 root root    36 1999-01-06 18:53 /mnt/cdrom/file1*
-rwxr--r--   1 root root   156 1999-01-06 18:53 /mnt/cdrom/file2*

It looks like 'world' has 'r' down the whole path. So why?

egag · 12-09-2004, 11:44 AM

i think you will need "x" permission on /mnt/cdrom to do "ls" or "cd---"
( use " #chmod 755 /mnt/cdrom " )

egag

ringwraith · 12-09-2004, 11:56 AM

I think egag is right because here is mine:

[12:55:14][user@myhost:~]$ ls -l /mnt
total 18
dr-xr-xr-x 10 root root 2048 2004-11-21 17:10 cdrom
dr-xr-xr-x 6 root root 4096 2004-09-11 11:57 cdrw
drwxr-xr-x 2 root root 4096 2002-03-16 02:34 floppy
drwxr-xr-x 2 root root 4096 2002-03-16 02:34 hd
drwxr-xr-x 2 root root 4096 2004-12-01 21:23 windows

tortle · 12-09-2004, 07:48 PM

chmod doesn't seem to work here:

Code:

root@myhost:~# chmod 755 /mnt/cdrom/
chmod: changing permissions of `/mnt/cdrom/': Read-only file system
root@myhost:~# ls -ld /mnt/cdrom/
drwxr--r--  17 root root 26 1999-02-20 14:11 /mnt/cdrom//

egag · 12-09-2004, 08:07 PM

do you have a cd in that drive and mounted it ?
i think you need to unmount it before doing a " chmod " .

else... try " # chmod a +x /mnt/cdrom "

egag

tortle · 12-10-2004, 11:39 AM

egag and ringwraith:

Thanks for the replies. I was re-reading the mount man page and I realized that I had mounted the device with:

Code:

mount cdrom

instead of:

Code:

mount /dev/cdrom

I don't know why the first command worked, but it resulted (as you saw) in the filesystem being mounted "rwxr--r--".

After I unmounted the device and re-mounted it with the full device name, it came up mounted "rwxr-xr-x" and all was OK.

I'd like to understand why this happened, but for now at least the problem is solved. Thanks.

breezewax · 11-21-2005, 11:35 PM

sorry for dragging up such an old thread, but hey...

So when I mount /dev/cdrom under root, other users can access the CDROM, but does that mean i'll have to "su" to mount it everytime anyone in my house wants to use the CDROM drive?

thanks! LQ rocks!

cathectic · 11-22-2005, 05:33 AM

Add a line to /etc/fstab, e.g.

Code:

/dev/hdc /mnt/cdrom iso9660,udf noauto,users,ro 0 0

Anyone can then type "mount /mnt/cdrom" to mount the drive, or "umount /mnt/cdrom" to unmount it.