ghost.c

#include <netdb.h>   
#include <stdio.h>   
#include <stdlib.h>   
#include <string.h>   
#include <errno.h>   
#define CANARY "in_the_coal_mine"   
struct {   
  char buffer[1024];   
  char canary[sizeof(CANARY)];   
} temp = { "buffer", CANARY };   
int main(void) {   
  struct hostent resbuf;   
  struct hostent *result;   
  int herrno;   
  int retval;   
  /*** strlen (name) = size_needed -sizeof (*host_addr) - sizeof (*h_addr_ptrs) - 1; ***/   
  size_t len = sizeof(temp.buffer) -16*sizeof(unsigned char) - 2*sizeof(char *) - 1;   
  char name[sizeof(temp.buffer)];   
  memset(name, '0', len);   
  name[len] = '\0';   
  retval = gethostbyname_r(name,&resbuf, temp.buffer, sizeof(temp.buffer), &result, &herrno);   
  if (strcmp(temp.canary, CANARY) !=0) {   
    puts("vulnerable");   
    exit(EXIT_SUCCESS);   
  }   
  if (retval == ERANGE) {   
    puts("notvulnerable");   
    exit(EXIT_SUCCESS);   
  }   
  puts("should nothappen");   
  exit(EXIT_FAILURE);   
}