UNIX for Advanced & Expert Users

Is there a way to allow a user to use sudo cp on a specific directory and only a specific file?

Kind of, but may not offer all the flexibility you want. For instance, to allow user nh2 to copy foo to /home/bar, put in your /etc/sudoers file

Code:

nh2  ALL=(ALL) NOPASSWD: /bin/cp foo /home/bar

Drawbacks are (among others):
HTH,
/Lew

I would reccomend you check setuid.

You can make a shell script and a small c program to call it with root privileges.

So an example :
You make shell script with USER named test.sh which does cp file1 /etc/
Then you make a C program called execshell (or whatever) which runs that script with system call ( please find examples online for C setuid and system call )

Compile that program.

As root you make chown root:root and chmod 4755 to that C program.
User can now invoke that c program which will execute that shell script with root permisions and copy the file1 to /etc/ as root invoked by USER.

Be carefull tho, setuid needs to be handled with care.
passwd would be a lovely example of setuid in C and exceptions it uses.

Hope that helps.
Regards
Peasant.

Instead of trying to restrict a program that gives him permissions to copy any file, why not use ordinary file permissions to control his access?

The only way that would be possible is if I give write permission on the /etc directory. I don't think thats a good idea. The /etc/resolv.conf keeps getting messed up. I want ordinary users to able to use internet and thats not possible right now with the dns not being set properly. The only way I can think of is by allowing a user to use sudo cp on a specific directory and only a specific file.

Is that a real problem? You could create a group for the users that need to edit /etc/resolv.conf, gives write permission to /etc/ and /etc/resolv.conf for that group. As long as the other files in /etc doesn't belong to this group, these users won't be able to mess-up those files (files in /etc belong normally to root:root).

Corona is right: If doable, this way should be prefered over sudo/cp.

Brgds,
/Lew

Not true, directory permissions don't control that. If you chown :group /etc/resolv.conf ; chmod g+rw /etc/resolv.conf then anyone in group will be able to modify it. Fixing /etc/resolv.conf every time it gets messed up isn't really a solution... It's like stocking extra fire extinguishers instead of fixing a smoking electrical short. If you don't want whatever autoconfig keeps messing up the file to do so, disable it.