Calling a script from a setuid root C program - script does not run as root

Question

I need to run a bash script as root (passwordless sudo or su not viable) and since you cannot setuid a script in Linux, I thought about calling it from an executable and mak

Answer 1

Another thing to note here is that the limitation here is from bash and not the *nix system itself. Bash actually make verifications on SUID scripts to only execute them with EUID root. If you take older shells, you will often get what you wanted out of the box. For example, sh doesn't make this kind of verifications:

$ cat wrapper.c
int main(void)
{
            system("/bin/sh -c whoami");
}

$ ls -l wrapper
-rwsr-sr-x 1 root users 8887 Feb 17 14:15 wrapper
$ ./wrapper
root

With bash:

$ cat wrapper.c
int main(void)
{
            system("/bin/bash -c whoami");
}

$ ls -l wrapper
-rwsr-sr-x 1 root users 8887 Feb 17 14:18 wrapper
$ ./wrapper
skinp

Still, Tom's answer is generally the way to go for making a wrapper for SUID root programs