[ILUG-BOM] SUID, c shell script

Hello all,

Approx a week back I got the info that I need to use a C program to execute a command a root for web scripts (PHP). I have given that a try, I created a

addnewhost.cpp :

#include <stdlib.h> int main() { system("/usr/sbin/useradd newusernewuser"); return 0; }

Compiled, linked and suid it as (Did this as root)

g++ -c addnewhost.cpp g++ -o addnewhost.bin addnewhost.o chown root.root addnewhost.bin chmod 4755 addnewhost.bin

But when I try to run the addnewhost.bin as a normal user it says

useradd: unable to lock password file

But runs fine as root. Any clues where should I go next. All I need to do is execute some command as a superuser but from a PHP page. Thanks in advance.

Bye.