[TriLUG] Help with setuid C wrapper script

Ron Kelley rkelleyrtp at gmail.com
Wed Oct 13 08:31:34 EDT 2010

Thanks for the syntax Jonathan.  However, this is what happens when I try to do the command:

[root at test-svr1 ~]# ssh rmaint at "tail -100 /var/log/messages"
tail: cannot open `/var/log/messages' for reading: Permission denied

Here is what is in /etc/sudoers:
rmaint ALL=(root) NOPASSWD: /usr/bin/tail -100 /var/log/messages, /usr/bin/tail -50 /var/log/secure

Also, /var/log/messages and /var/log/secure both have permission mod of 600 (as in, rw--------).

I have tried various syntax lines in /etc/sudoers but always get permission denied.  In fact, this is what I tried prior to sending the original email to the alias.  Thus, I had to fall back to a suid C program.  Have you tried the above statements in your sudoers file?

BTW - I have the suid C program working fine.  But, as we all know, keeping a single suid utility updated and pushed out to all servers is a real PITA.

Thanks again,


On Oct 12, 2010, at 8:23 PM, Jonathan Woodbury wrote:

> Ron,
> Based on what I can see in your first few emails on this, I believe this
> will give you precisely what you asked for:
> someuser ALL=(root) NOPASSWD: /usr/bin/tail -100 /var/log/messages,
> /usr/bin/tail -50 /var/log/secure
> This will allow someuser to execute tail with those exact arguments as root
> without prompting the user for a password.  Some other folks have nicely
> pointed out that you could use syntax described in the Wildcards section of
> the sudoers man page to loosen the restrictions on what arguments could be
> passed to tail.  But it didn't look like you were heading in that direction
> from what I saw in your source code example.  Explicit and simple has its
> virtue.
> I hope this helps,
> Jonathan
> -- 
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