/* dumb vulnerable program example, that uses function pointers */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>

#define ERROR -1
#define BUFSIZE 64

void goodfunc()
{
   printf("I'm the real goodfunc().  I have been called.\n");
   return;
}

int main(int argc, char **argv)
{
   static char buf[BUFSIZE];
   static void (*funcptr)();

   if (argc <= 2)
   {
      fprintf(stderr, "Usage: %s <string1> <string2>\n", argv[0]);
      exit(ERROR);
   }

   funcptr = &goodfunc;
   memset(buf, 0, BUFSIZE);

   printf("argv[1] = %p\n", argv[1]);
   printf("buf = %p\n\n", buf);

   printf("before: funcptr = %p\n", funcptr);
   strncpy(buf, argv[2], strlen(argv[2]));
   printf("after: funcptr = %p\n\n", funcptr);

   (*funcptr)();
   return 0;
}