A very small C wrapper for running shell scripts suid. Pretty dangerous, but handy.

suid-wrapper.c

#include <unistd.h>
#include <errno.h>

main( int argc, char ** argv, char ** envp )
{
              if( setgid(getegid()) ) perror( "setgid" );
              if( setuid(geteuid()) ) perror( "setuid" );
              envp = 0; /* blocks IFS attack on non-bash shells */
              system( "/path/to/bash/script", argv, envp );
              perror( argv[0] );
              return errno;
}

how do you compile this? system() accepts only single argument

I implemented a utility to make creating executable binaries with suid flag set a bit easier: https://github.com/thiagorb/suid-wrapper

With this utility you can create new binaries without having to write or modify source code, and you also don't need to compile (and therefore no compiler needed).