C Language, setuid warpper problem

itzi
#1 / 6

setuid warpper problem

I want to have a bash scripts run setuid as root, The bash
script('do_something') suppose to write to a file('/var/filename')
that has an root owner and -rw--r--r permission
So I've created a C-wrapper that calls the script with permissions
4755 and has an root owner.
I have no problem to run the C-program as root, but when I am trying
to execute it as regular user I get a Permission denied message.

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

int main(){

if((pid = fork()) == -1)
return -1;

if(pid == 0){
char *args[2];

args[0] = "./do_something";
args[1] = "/var/filename";
args[2] = NULL;

setuid(0);
rc = execv(args[0], args);

exit(rc);
}

rc = wait(NULL);

Quote:

}

does anyone know what is wrong ?
how can i let a regular user run that script with superuser
permissions ?

Thanks for any information

Itzik

Fri, 04 Feb 2005 20:36:34 GMT

#2 / 6

setuid warpper problem

Wed, 18 Jun 1902 08:00:00 GMT

Preben Tr?ru
#3 / 6

setuid warpper problem

Quote:

> I want to have a bash scripts run setuid as root, The bash
> script('do_something') suppose to write to a file('/var/filename')
> that has an root owner and -rw--r--r permission
> So I've created a C-wrapper that calls the script with permissions
> 4755 and has an root owner.
> I have no problem to run the C-program as root, but when I am trying
> to execute it as regular user I get a Permission denied message.

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

> int main(){

> if((pid = fork()) == -1)
> return -1;

> if(pid == 0){
> char *args[2];

> args[0] = "./do_something";
> args[1] = "/var/filename";
> args[2] = NULL;

> setuid(0);

AFAIR
A program may only success in a setuid (0) call if owned by root and
only if permissions on file has the sticky bit set (chmod 4555) thus
root granted you permissions to run this program with root permissions.

Fri, 04 Feb 2005 20:54:16 GMT

#4 / 6

setuid warpper problem

Wed, 18 Jun 1902 08:00:00 GMT

Wolf Gross
#5 / 6

setuid warpper problem

after compile, do a

chown root wrapper
chgrp root wrapper
chmod ugo+s wrapper

hth,
Wolf

Fri, 04 Feb 2005 21:01:19 GMT

Keith Thompso
#6 / 6

setuid warpper problem

Quote:

> I want to have a bash scripts run setuid as root, The bash
> script('do_something') suppose to write to a file('/var/filename')
> that has an root owner and -rw--r--r permission
> So I've created a C-wrapper that calls the script with permissions
> 4755 and has an root owner.

[...]

This isn't really a C question. Try comp.unix.programmer.

--

San Diego Supercomputer Center <*> <http://www.sdsc.edu/~kst>
Schroedinger does Shakespeare: "To be *and* not to be"

Sat, 05 Feb 2005 03:15:23 GMT