cdrecord: behaves as if not suid root when it is, sorta.
Hi. I've used cdrecord lots of times, but I've just recently run into
an odd problem. When I use cdrecord as a non-root user, I get warning
messages that are not present if I use cdrecord as root:
cdrecord: Operation not permitted. WARNING: Cannot set RR-scheduler
cdrecord: Permission denied. WARNING: Cannot set priority using setpriority().
cdrecord: WARNING: This causes a high risk for buffer underruns.
>From searching the web/newsgroups, I can see that this is fairly
common -- cdrecord needs to be run as root, or as suid root. However,
there are a few important differences. First, I *don't* also get the
warning message of:
cdrecord: Operation not permitted. WARNING: Cannot do mlockall(2).
which usually comes with trying to run cdrecord as non-root and
without suid root access. Second, cdrecord *does* proceed to the
write -- it doesn't say:
cdrecord: Read-only file system. Cannot open '/dev/cdrom'. Cannot open SCSI driver.
cdrecord: For possible targets try 'cdrecord -scanbus'. Make sure you are root.
and quit like it normally does if you try to run it as non-root and
without suid root access. And finally, and most importantly,
my cdrecord *is* suid root:
stax:/usr/src-789> ls -al /usr/bin/cdrecord
-rws--s--- 1 root cdrom 314476 May 14 05:28 /usr/bin/cdrecord*
Other potentially useful info:
cmetzler cdrom floppy audio dip src video users
stax:/usr/src-791> ls -al /dev/scd0
brw-rw---- 1 root cdrom 11, 0 Aug 27 2002 /dev/scd0
stax:/usr/bin-805> dir /usr/bin/cdrdao
-rwsr-xr-x 1 root root 532292 Oct 15 2002 /usr/bin/cdrdao*
Does anyone have a clue why I'm getting these warning messages? What
have I missed?
Chris Metzler email@example.com
(remove "snip-me." to email)
"As a child I understood how to give; I have forgotten this grace since I
have become civilized." - Chief Luther Standing Bear