Re: Permissions 101

[Cliff Sarginson <cliff@raggedclown.net>]

On Mon, Jan 15, 2001 at 02:20:48PM -0500, Bob Bernstein wrote:
> I'm trying to understand the suid bit. So I created a little script to list
> a file that I don't as a normal user have permission to read, namely
> /var/log/user.log. Here's the data, starting with the permissions on
> user.log:
> 
> $ ls -l /var/log/user.log
> -rw-r-----    1 root     adm          2838 Jan 15 13:39 /var/log/user.log
> 
> Here's my little script "sutest", and its permissions, followed by the
> results of executing it:
> 
> $ less sutest
> #! /bin/bash
> echo "does this work?"
> less /var/log/user.log
> 
> $ ls -l sutest
> -rwsr-xr-x    1 root     root          59 Jan 15 13:28 sutest
> 
> $ ./sutest
> does this work?
> /var/log/user.log: Permission denied
> 
Suid shell scripts don't work.
Big security problem.. :)

Cliff