change-uid-gid-based-one-right-of-file => gcc -m32 -o droit-user droit-user.c

exec_as_uid_set_by_c_script

#!/tmp/sh
echo "Content repository of" `whoami`
# ou echo "Contenu du répertoire de" $(whoami)
ls -a /home/user

right-user.c

#include <unistd.h>

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

extern char **environ;
extern int errno;

int main (int argc, char **argv) {
  uid_t uid, euid;
  char *name[2];

  uid=getuid();
  euid=geteuid();
  name[0] = "/tmp/sh";
  name[1] = "/tmp/exec_as_uid_set_by_c_script";
  
  printf ("UID %d - EUID %d\n", uid, euid);
  
  setreuid (1408, 1408);
  setuid(1408);
  setgid(1408);
  uid=getuid();
  euid=geteuid();
  
  printf ("UID %d - EUID %d\n", uid, euid);
  execve(name[0], name, environ);
  
  printf ("Error : %d\n", errno);
  return errno;

}