#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>

int main(void)
{

int current_uid = getuid();
printf(”My UID is: %d. My GID is: %d\n”, current_uid, getgid());
system(”/usr/bin/id”);

if (setuid(0))
{

perror(”setuid”);
return 1;

}

//I am now root!
printf(”My UID is: %d. My GID is: %d\n”, getuid(), getgid());
system(”/usr/bin/id”);

//Time to drop back to regular user priviledges
setuid(current_uid);
printf(”My UID is: %d. My GID is: %d\n”, getuid(), getgid());
system(”/usr/bin/id”);

return 0;

}

adam@staging:~$ gcc -O2 -ggdb -o setuid setuid.c
adam@staging:~$ ls -al setuid
-rwxr-xr-x 1 adam adam 9792 2009-10-03 18:09 setuid
adam@staging:~$