cdrecord problem

[The General]

i believe i have a problem with cdrecord

i can burn DVDs as normal user, and i can as root, (im using k3b) but i can only burn CDs as root.

at one point k3b said i was using an unpatched version of cdrecord, but most of the time it says "probably a buffer underrun occured"

clearly its working, i just have something messed up to where i cant burn as normal user. i'm in the cdrom group if that matters

i did dpkg-reconfigure cdrecord and told it no when asking if i wanted to make cdrecord suid root, btw, what does that mean?

any suggestions?

 

[horndude]

suid root means an app runs as though it was invoked by root

look up the chmod and chown commands

 

[The General]

ah okay i think i understand suid root, but i got the cdrecord thing figured out. but theres one thing i dont understand and thats if apps are installed suid root, why dont i need the root password to run them?

 

[horndude]

because linux attaches a set of "description" bits to each and every file, and because linux treats everything as a file including devices it applies to everything in the system

these description bits alter who can run an app, who owns the app, plus read,write permissions

some apps do better if they run with root priveledges because some system calls and other system level apps are needed to make them work properly, cdrecord is one of them---the userland space is seperated from system space, but sometimes a userland app needs to be treated like a kernel level system app---cdrecord is like this

the suid bit allows you to do this without invoking the normal root login or sudo, BUT, suppose you do this as a user but the app crashes in the middle, it will usually leave the user in a root shell---it is a security risk

 

[The General]

that seems like a simple thing to fix, doesnt it?

 

[horndude]

ya, its more like a hack though, but its one of those ones thats pretty safe really