Phreaker & Shawn the R0ck - Sep 4

------------------------------------------------------------------------
Requirement:

A bunch of scripts are designed to do something, which only the "root"
can do. But we don't want them run as "root". It will cause more risk
in a complicated environment that we called "cloud".

This kind of issue can be solved by setuid() if it's a binary
program. Here, it's not. It's just some bash scripts. Even you put
setuid flag onto the scripts, the *SHELL* program will drop privileges
while it loads the scripts. So..that's the problem we have...........


Implementation:

We write a very simple program is called setuid_script_helper. You might
find other similiar implementations in the cyberworld. Plz, let me
know.

Let's see an example here:
------------------------------------------------------------------------

Preparation:
------------------------------------------------------------------------
shawn@shawn-fortress /tmp/setuid_script_helper $ cd example/
shawn@shawn-fortress /tmp/setuid_script_helper/example $ sudo ./run_me.sh 
[sudo] password for shawn: 
gcc -g   -o setuid_script_helper setuid_script_helper.c
done
/tmp/setuid_script_helper/example

Run 2.sh as an unpriviledged user, it failed to run:
------------------------------------------------------------------------
shawn@shawn-fortress /tmp/setuid_script_helper/example $ ./2.sh 
uid=1000(shawn) gid=1000(shawn) groups=1000(shawn),4(adm),24(cdrom),27(sudo),30(dip),46(plugdev),108(lpadmin),110(sambashare),1002(promiscuous)
./2.sh: 4: ./2.sh: cannot create /proc/sys/kernel/randomize_va_space: Permission denied


Use the *helper*:
------------------------------------------------------------------------
shawn@shawn-fortress /tmp/setuid_script_helper/example $ ./setuid_script_helper "./2.sh"
Run script:[./2.sh]
my uid: 0
Set uid to 0 , return code is 0!
uid=0(root) gid=1000(shawn) groups=0(root),4(adm),24(cdrom),27(sudo),30(dip),46(plugdev),108(lpadmin),110(sambashare),1000(shawn),1002(promiscuous)
Script executed, return code is 0!
------------------------------------------------------------------------


There's only one thing you need to note about deploment file's
permission( user:group):

==> user: must be *root*
==> group: must be the one you deployed, like *shawn*


We'd like you buy you a beer if you improve this program;-)