File: fuzz_dhcpc6.c

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thc-ipv6 3.6-1
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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/wait.h>
#include <time.h>
#include <pcap.h>
#include <netinet/in.h>
#include <sys/select.h>
#include "thc-ipv6.h"

int do_fuzzer();

#define COUNT_FLAG     11
#define COUNT_BYTE      4
#define COUNT_WORD     16
#define COUNT_XOR       2
#define COUNT_EXTEND  256
#define COUNT_DWORD   256

#define NEVER 2000000000
#define TEST_MAX (NEVER - 1)

#define DO_SOL 1
#define DO_ADV 2
#define DO_REQ 3
#define DO_CON 4
#define DO_REN 5
#define DO_REB 6
#define DO_REP 7
#define DO_REL 8
#define DO_DEC 9
#define DO_REC 10
#define DO_NFO 11
#define DO_REL_FOR 12
#define DO_REL_REP 13


/*
 * Fuzzing data types:
 *  F = flags = 1 byte = 8 bits | flags | 8 ; 256
 *  B = byte = 1 byte | 0 1 254 255 xor XOR | 6 ; 256
 *  X = byte = 1 byte | all values from 0 to 255
 *  W = word = 2 bytes | 0,1,254,255^2 xor XOR | 18 ; 65536
 *  D = double word = 4 bytes | {0,1,254,255}^4 xor XOR | 258 ; 4294967295
 *  . = byte = ignore, jump over
 *
 */
struct OPT {
  char tag;
  char fuzz[45];
  char dont_fuzz[45];
  char label[45];
  char code[45];
  int length;
} options[22] = {
  {
    'x', "Xx", ".x", "DCHP MESSAGE TYPE", {
  0x02}, 1}, {
    'y', "BBBy", "...y", "TRANSACTION ID", {
  0x00, 0x00, 0x00}, 3}, {
    'z', "....WWDWWWz", "..................z", "CLIENTID", {
  0x00, 0x01, 0x00, 0x0E, 'C', 'L', 'I', 'E', 'N', 'T', ' ', 'I', 'D', ' ', 'D', 'U', 'I', 'D'}, 18}, {
    'a', "....WWDWWWa", "..................a", "SERVERID (a)", {
  0x00, 0x02, 0x00, 0x0E, 0x00, 0x01, 0x00, 0x01, 0x1A, 0x62, 0xB6, 0x77, 'D', 'I', 'D', 'U', 'I', 'D'}, 18}, {
    'b', "....DDDb", "................b", "IA_NA (b)", {
  0x00, 0x03, 0x00, 0x0C, 0x01, 0x02, 0x03, 0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0A}, 16}, {
    'c', "....DWWWWc", "................c", "IA_TA (c)", {
  0x00, 0x04, 0x00, 0x0C, 0x01, 0x02, 0x03, 0x04, 0x00, 0x0D, 0x00, 0x04, 0x00, 0x00, 'O', 'K'}, 16}, {
    'd', "................DD...Xd", "............................d", "IAADR (d)", {
  0x00, 0x05, 0x00, 0x18, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x00, 0x0D, 0x00, 0x00,}, 28}, {
    'e', "....XXe", "......e", "ORO (e)", {
  0x00, 0x06, 0x00, 0x02, 0x00, 0x08}, 6}, {
    'f', "....Xf", ".....f", "PREFERENCE (f)", {
  0x00, 0x07, 0x00, 0x01, 0x00}, 5}, {
    'g', "....BBg", "......g", "ELAPSED_TIME (g)", {
  0x00, 0x08, 0x00, 0x02, 0x10, 0xFF}, 6}, {
    'h', ".....BB...............B...............h", "......................................h", "RELAY_MSG (h)", {
  0x00, 0x09, 0x00, 0x22, 0x0C, 0x0F, 'L', 'I', 'N', 'K', ' ', 'A', 'D', 'D', 'R', 'E', 'S', 'S', 0x0D, 0x0E, 0x0F, 0x10, 'P', 'E', 'E', 'R', ' ', 'A', 'D', 'D', 'R', 'E',
        'S', 'S', 0x0D, 0x0E, 0x0F, 0x10}, 38}, {
    'i', "....BBBDD.....DB................i", ".........................................i", "AUTHENTICATION (i)", {
  0x00, 0x0B, 0x00, 0x25, 0x00, 0x01, 0x00, 'R', 'E', 'P', 'L', 'A', 'Y', 0x07, 0x08, 'R', 'E', 'A', 'L', 'M', 'K', 'E', 'Y', 0x04, 0x05, 'H', 'M', 'A', 'C', '-', 'M', 'D',
        '5', 0x09, 0x0A, 0xB, 0x0C, 0x0D, 0x0E, 0x0F, 0x10}, 41}, {
    'j', "....DDDDj", "....................j", "UNICAST (j)", {
  0x00, 0x0C, 0x00, 0x10, 'U', 'N', 'I', 'C', 'A', 'S', 'T', ' ', 'A', 'D', 'D', 'R', 'E', 'S', 'S', 0x10}, 20}, {
    'k', "....XX..............k", "....................k", "STATUS_CODE (k)", {
  0x00, 0x0D, 0x00, 0x10, 0x00, 0x00, 'S', 'T', 'A', 'T', 'U', 'S', ' ', 'M', 'E', 'S', 'S', 'A', 'G', 'E'}, 20}, {
    'l', "...Bl", "....l", "RAPID_COMMIT (l)", {
  0x00, 0x0E, 0x00, 0x00}, 4}, {
    'm', "......Dm", "..........m", "USER_CLASS (m)", {
  0x00, 0x0F, 0x00, 0x06, 0x00, 0x04, 'U', 'S', 'E', 'R'}, 10}, {
    'n', "....D.......n", "...............n", "VENDOR_CLASS (n)", {
  0x00, 0x10, 0x00, 0x0B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x05, 'C', 'L', 'A', 'S', 'S'}, 15}, {
    'o', "....D..........o", "..................o", "VENDOR_OPTS (o)", {
  0x00, 0x11, 0x00, 0x0E, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x06, 'O', 'P', 'T', 'I', 'O', 'N'}, 18}, {
    'p', ".................Bp", "..................p", "INTERFACE_ID (p)", {
  0x00, 0x12, 0x00, 0x0E, 'I', 'N', 'T', 'E', 'R', 'F', 'A', 'C', 'E', ' ', 'I', 'D', ' ', ' '}, 18}, {
    'q', "....Xq", ".....q", "RECONF_MSG (q)", {
  0x00, 0x13, 0x00, 0x01, 0x00}, 5}, {
    'r', "....Br", ".....r", "RECONF_ACCEPT (r)", {
  0x00, 0x14, 0x00, 0x01, 0x00}, 5}, {
    's', "", "", "FUZZING BUFFER ERROR! (s)", {
0x00}, 1},};

unsigned short int words[] = { 0x0000, 0x0001, 0x00fe, 0x00ff, 0x0100, 0x0101,
  0x01fe, 0x01ff, 0xfe00, 0xfe01, 0xfefe, 0xfeff, 0xff00, 0xff01, 0xfffe,
  0xffff
};                              // 16

unsigned int xors[] = { 0, 0xffffffff };        // 2

unsigned char extends[] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
  15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33,
  34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52,
  53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71,
  72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90,
  91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107,
  108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122,
  123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137,
  138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152,
  153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167,
  168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 182,
  183, 184, 185, 186, 187, 188, 189, 190, 191, 192, 193, 194, 195, 196, 197,
  198, 199, 200, 201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 212,
  213, 214, 215, 216, 217, 218, 219, 220, 221, 222, 223, 224, 225, 226, 227,
  228, 229, 230, 231, 232, 233, 234, 235, 236, 237, 238, 239, 240, 241, 242,
  243, 244, 245, 246, 247, 248, 249, 250, 251, 252, 253, 254, 255
};                              // 256

unsigned int dwords[] = { 0x00000000, 0x00000001, 0x000000fe, 0x000000ff,
  0x00000100, 0x00000101, 0x000001fe, 0x000001ff,
  0x0000fe00, 0x0000fe01, 0x0000fefe, 0x0000feff,
  0x0000ff00, 0x0000ff01, 0x0000fffe, 0x0000ffff,
  0x00010000, 0x00010001, 0x000100fe, 0x000100ff,
  0x00010100, 0x00010101, 0x000101fe, 0x000101ff,
  0x0001fe00, 0x0001fe01, 0x0001fefe, 0x0001feff,
  0x0001ff00, 0x0001ff01, 0x0001fffe, 0x0001ffff,
  0x00fe0000, 0x00fe0001, 0x00fe00fe, 0x00fe00ff,
  0x00fe0100, 0x00fe0101, 0x00fe01fe, 0x00fe01ff,
  0x00fefe00, 0x00fefe01, 0x00fefefe, 0x00fefeff,
  0x00feff00, 0x00feff01, 0x00fefffe, 0x00feffff,
  0x00ff0000, 0x00ff0001, 0x00ff00fe, 0x00ff00ff,
  0x00ff0100, 0x00ff0101, 0x00ff01fe, 0x00ff01ff,
  0x00fffe00, 0x00fffe01, 0x00fffefe, 0x00fffeff,
  0x00ffff00, 0x00ffff01, 0x00fffffe, 0x00ffffff,
  0x01000000, 0x01000001, 0x010000fe, 0x010000ff,
  0x01000100, 0x01000101, 0x010001fe, 0x010001ff,
  0x0100fe00, 0x0100fe01, 0x0100fefe, 0x0100feff,
  0x0100ff00, 0x0100ff01, 0x0100fffe, 0x0100ffff,
  0x01010000, 0x01010001, 0x010100fe, 0x010100ff,
  0x01010100, 0x01010101, 0x010101fe, 0x010101ff,
  0x0101fe00, 0x0101fe01, 0x0101fefe, 0x0101feff,
  0x0101ff00, 0x0101ff01, 0x0101fffe, 0x0101ffff,
  0x01fe0000, 0x01fe0001, 0x01fe00fe, 0x01fe00ff,
  0x01fe0100, 0x01fe0101, 0x01fe01fe, 0x01fe01ff,
  0x01fefe00, 0x01fefe01, 0x01fefefe, 0x01fefeff,
  0x01feff00, 0x01feff01, 0x01fefffe, 0x01feffff,
  0x01ff0000, 0x01ff0001, 0x01ff00fe, 0x01ff00ff,
  0x01ff0100, 0x01ff0101, 0x01ff01fe, 0x01ff01ff,
  0x01fffe00, 0x01fffe01, 0x01fffefe, 0x01fffeff,
  0x01ffff00, 0x01ffff01, 0x01fffffe, 0x01ffffff,
  0xfe000000, 0xfe000001, 0xfe0000fe, 0xfe0000ff,
  0xfe000100, 0xfe000101, 0xfe0001fe, 0xfe0001ff,
  0xfe00fe00, 0xfe00fe01, 0xfe00fefe, 0xfe00feff,
  0xfe00ff00, 0xfe00ff01, 0xfe00fffe, 0xfe00ffff,
  0xfe010000, 0xfe010001, 0xfe0100fe, 0xfe0100ff,
  0xfe010100, 0xfe010101, 0xfe0101fe, 0xfe0101ff,
  0xfe01fe00, 0xfe01fe01, 0xfe01fefe, 0xfe01feff,
  0xfe01ff00, 0xfe01ff01, 0xfe01fffe, 0xfe01ffff,
  0xfefe0000, 0xfefe0001, 0xfefe00fe, 0xfefe00ff,
  0xfefe0100, 0xfefe0101, 0xfefe01fe, 0xfefe01ff,
  0xfefefe00, 0xfefefe01, 0xfefefefe, 0xfefefeff,
  0xfefeff00, 0xfefeff01, 0xfefefffe, 0xfefeffff,
  0xfeff0000, 0xfeff0001, 0xfeff00fe, 0xfeff00ff,
  0xfeff0100, 0xfeff0101, 0xfeff01fe, 0xfeff01ff,
  0xfefffe00, 0xfefffe01, 0xfefffefe, 0xfefffeff,
  0xfeffff00, 0xfeffff01, 0xfefffffe, 0xfeffffff,
  0xff000000, 0xff000001, 0xff0000fe, 0xff0000ff,
  0xff000100, 0xff000101, 0xff0001fe, 0xff0001ff,
  0xff00fe00, 0xff00fe01, 0xff00fefe, 0xff00feff,
  0xff00ff00, 0xff00ff01, 0xff00fffe, 0xff00ffff,
  0xff010000, 0xff010001, 0xff0100fe, 0xff0100ff,
  0xff010100, 0xff010101, 0xff0101fe, 0xff0101ff,
  0xff01fe00, 0xff01fe01, 0xff01fefe, 0xff01feff,
  0xff01ff00, 0xff01ff01, 0xff01fffe, 0xff01ffff,
  0xfffe0000, 0xfffe0001, 0xfffe00fe, 0xfffe00ff,
  0xfffe0100, 0xfffe0101, 0xfffe01fe, 0xfffe01ff,
  0xfffefe00, 0xfffefe01, 0xfffefefe, 0xfffefeff,
  0xfffeff00, 0xfffeff01, 0xfffefffe, 0xfffeffff,
  0xffff0000, 0xffff0001, 0xffff00fe, 0xffff00ff,
  0xffff0100, 0xffff0101, 0xffff01fe, 0xffff01ff,
  0xfffffe00, 0xfffffe01, 0xfffffefe, 0xfffffeff,
  0xffffff00, 0xffffff01, 0xfffffffe, 0xffffffff
};                              // 256

char tribyte_id[4] = { 0, 0, 0, 0 };
int fdebug = 0;
unsigned char *dst;
unsigned char flags[] = { 0, 1, 2, 4, 8, 16, 32, 64, 128, 254, 255 };   // 11
unsigned char bytes[] = { 0, 1, 254, 255 };     // 4
char mac[6] = { 0, 0x0c, 0, 0, 0, 0 }, *pkt = NULL; // defines mac as 6 pieces and defines pkt as null.
char wdatabuf[2048]; //builds data buffer and sets memory size at 1024mb
unsigned char *mac6 = mac, *src;  //creates mac6 address usuing
int i, s, len, pkt_len = 0, dlen = 0;
int do_all = 1, use_real_mac = 1, use_real_link = 1;
int port = -1;
int listen_for_clients = 1;
char victim[128] = "fe80::20c:29ff:fe3f:e572";
int cidflag = 0;
int oflg = 0;
int f_cnt = 0;
int p_cnt = 0;
unsigned char cid[14] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
int lidx = 0;
char mac_fuzz[] = "..............";
char ipv6_fuzz[] = "........................................";
char udp_header_fuzz[] = "........";
char option_string[100] = "abcdefghijklmnopqr";
char fuzzing_mask[512];
char *interface = NULL;
int test_start = 0, test_end = TEST_MAX, ping = NEVER, no_send = 1, got_packet = 0;
int xid = 0;
pcap_t *p = NULL;
int do_type = DO_ADV, fuzz_dhcp_msg = 0;
unsigned char rdatabuf[1024];
unsigned char *ptr1, *ptr2;
static struct iovec iov;
struct sockaddr_storage from;
struct msghdr mhdr;
struct sockaddr_in6 ddst;
char cmsgbuf[1024];
int fromlen = 0, len, s, t;

void help(char *prg) {
  printf("%s %s (c) 2019 by %s %s\n", prg, VERSION, "Darrell Ambro", RESOURCE);
  printf("Partially based on code by Brandon Hutcheson and Graeme Neilson\n\n");
  printf("Syntax: %s  [-1|-2|-3|-4|-5|-6|-7|-8|-9|-A|-B|-C|-D|-m] -f mac -l link -v ipv6 -x xid -c client -o options interface\n\n", prg);
  printf("Options:\n");
  printf("  -1         fuzz DHCPv6 Solicit\n");
  printf("  -2         fuzz DHCPv6 Advertise (default)\n");
  printf("  -3         fuzz DHCPv6 Request\n");
  printf("  -4         fuzz DHCPv6 Confirm\n");
  printf("  -5         fuzz DHCPv6 Renew\n");
  printf("  -6         fuzz DHCPv6 Rebind\n");
  printf("  -7         fuzz DHCPv6 Reply\n");
  printf("  -8         fuzz DHCPv6 Release\n");
  printf("  -9         fuzz DHCPv6 Decline\n");
  printf("  -A         fuzz DHCPv6 Reconfigure\n");
  printf("  -B         fuzz DHCPv6 Information Request\n");
  printf("  -C         fuzz DHCPv6 Relay-Forward\n");
  printf("  -D         fuzz DHCPv6 Relay-reply\n");
  printf("  -m         fuzz the message type as well\n");
  printf("  -v ipv6    IPv6 address of victim (if not specified DHCP clients sending messages are attacked)\n");
  printf("  -x xid     Transaction ID of victim - zero for random (ignored if -v not specified) \n");
  printf("  -c client  Client ID of victim - zero for random (ignored if -v not specified) \n");
  printf("  -f mac     spoof the mac address\n");
  printf("  -l link    spoof the link address\n");
  printf("  -o options DHCPv6 message options to send (default: abcdefghijklmonpqr)\n");
  printf("       a  OPTION_SERVERID\n");
  printf("       b  OPTION_IA_NA\n");
  printf("       c  OPTION_IA_TA\n");
  printf("       d  OPTION_IAADR\n");
  printf("       e  OPTION_ORO\n");
  printf("       f  OPTION_PREFERENCE\n");
  printf("       g  OPTION_ELAPSED_TIME\n");
  printf("       h  OPTION_RELAY_MSG\n");
  printf("       i  OPTION_AUTH\n");
  printf("       j  OPTION_UNICAST\n");
  printf("       k  OPTION_STATUS_CODE\n");
  printf("       l  OPTION_RAPID_COMMIT\n");
  printf("       m  OPTION_USER_CLASS\n");
  printf("       n  OPTION_VENDOR_CLASS\n");
  printf("       o  OPTION_VENDOR_OPTS\n");
  printf("       p  OPTION_INTERFACE_ID\n");
  printf("       q  OPTION_RECONF_MSG\n");
  printf("       r  OPTION_RECONF_ACCEPT\n");
  printf("\nFuzz messages sent to a DHCPv6 client\n");
  exit(-1);
}

int fuzz_loop(char *pkt, int *pkt_len) {
  int do_fuzz = 1;
  int test_pos = 0, test_ptr = 0, test_cnt = 0, test_current = 0;
  int do_it;
  int i;
  unsigned short int *sip;
  unsigned int *intp;
  int fragment = 0, frag_offset = 0;
  unsigned char *pkt_bak;
  thc_ipv6_hdr *hdr = (thc_ipv6_hdr *) pkt;

  // backup of generated packet
  pkt_bak = malloc(hdr->pkt_len);
  memcpy(pkt_bak, hdr->pkt, hdr->pkt_len);

  if (fdebug)
    printf("fuzzing_mask(%d): %s\n", strlen(fuzzing_mask), fuzzing_mask);
  if (fdebug)
    printf("Victim: %s\n", victim);
  while (do_fuzz) {
    if (test_cnt == 0)
      while (fuzzing_mask[test_ptr] == '.') {
        test_ptr++;
        test_pos++;
      }
    if ((int) fuzzing_mask[test_ptr] >= 'a') {
      for (lidx = 0; lidx < 21; ++lidx)
        if (fuzzing_mask[test_ptr] == options[lidx].tag)
          break;
      if (f_cnt == 0) {
        printf("%s not fuzzed\n", options[lidx].label);
      } else {
        if (options[lidx].tag < 's' || options[lidx].tag == 'z')
          printf("OPTION_%s %d messages (%d)\n", options[lidx].label, f_cnt, p_cnt + f_cnt);
        else
          printf("%s %d messages (%d)\n", options[lidx].label, f_cnt, p_cnt + f_cnt);
      }
      test_ptr++;
      p_cnt += f_cnt;
      f_cnt = 0;
      continue;
    }

    if (fuzzing_mask[test_ptr] == 0)
      do_fuzz = 0;

    test_cnt++;
    do_it = 1;


    if (fdebug)
      printf("fuzzing_mask[%d]: %c\n", test_ptr, fuzzing_mask[test_ptr]);
    switch (fuzzing_mask[test_ptr]) {
    case 0:
      break;
    case 'X':
      if (test_cnt <= COUNT_EXTEND) {
        if (pkt_bak[test_pos] != extends[test_cnt - 1])
          hdr->pkt[test_pos] = extends[test_cnt - 1];
        else
          do_it = 0;
      } else {
        test_cnt = 0;
        test_ptr++;
        test_pos++;
      }
      break;
    case 'B':
      if (test_cnt <= COUNT_BYTE) {
        if (pkt_bak[test_pos] != bytes[test_cnt - 1])
          hdr->pkt[test_pos] = bytes[test_cnt - 1];
        else
          do_it = 0;
      } else {
        i = 0;
        while (i < COUNT_BYTE && do_it) {
          if (bytes[i] == pkt_bak[test_pos])
            do_it = 0;
          i++;
        }
        if (do_it)
          hdr->pkt[test_pos] = hdr->pkt[test_pos] ^ xors[test_cnt - COUNT_BYTE - 1];
      }
      if (test_cnt == COUNT_BYTE + COUNT_XOR) {
        test_cnt = 0;
        test_ptr++;
        test_pos++;
      }
      break;
    case 'F':
      if (test_cnt <= COUNT_FLAG) {
        if (pkt_bak[test_pos] != flags[test_cnt - 1])
          hdr->pkt[test_pos] = flags[test_cnt - 1];
        else
          do_it = 0;
      } else {
        i = 0;
        while (i < COUNT_FLAG && do_it) {
          if (bytes[i] == pkt_bak[test_pos])    // yes, bytes[] is the right one even for flags
            do_it = 0;
          i++;
        }
        if (do_it)
          hdr->pkt[test_pos] = hdr->pkt[test_pos] ^ xors[test_cnt - COUNT_BYTE - 1];
      }
      if (test_cnt == COUNT_FLAG + COUNT_XOR) {
        test_cnt = 0;
        test_ptr++;
        test_pos++;
      }
      break;
    case 'W':
      sip = (unsigned short int *) &pkt_bak[test_pos];
      if (test_cnt <= COUNT_WORD) {
        if (*sip != words[test_cnt - 1])
          memcpy((char *) &hdr->pkt[test_pos], (char *) &words[test_cnt - 1], 2);
        else
          do_it = 0;
      } else {
        i = 0;
        while (i < COUNT_WORD && do_it) {
          if (words[i] == *sip)
            do_it = 0;
          i++;
        }
        if (do_it) {
          i = *sip ^ xors[test_cnt - COUNT_WORD - 1];
          sip = (unsigned short int *) &hdr->pkt[test_pos];
          *sip = i % 65536;
        }
      }
      if (test_cnt == COUNT_WORD + COUNT_XOR) {
        test_cnt = 0;
        test_ptr++;
        test_pos += 2;
      }
      break;
    case 'D':
      intp = (unsigned int *) &pkt_bak[test_pos];
      if (test_cnt <= COUNT_DWORD) {
        if (*intp != dwords[test_cnt - 1])
          memcpy((char *) &hdr->pkt[test_pos], (char *) &dwords[test_cnt - 1], 4);
        else
          do_it = 0;
      } else {
        i = 0;
        while (i < COUNT_DWORD && do_it) {
          if (dwords[i] == *intp)
            do_it = 0;
          i++;
        }
        if (do_it) {
          i = *intp ^ xors[test_cnt - COUNT_DWORD - 1];
          intp = (unsigned int *) &hdr->pkt[test_pos];
          *intp = (unsigned int) i;
//          *intp = (unsigned int) (i % 4294967295);
        }
      }
      if (test_cnt == COUNT_DWORD + COUNT_XOR) {
        test_cnt = 0;
        test_ptr++;
        test_pos += 4;
      }
      break;
    default:
      fprintf(stderr, "This character should not be in the fuzz string: %c(%d) position %d string %s\n", fuzzing_mask[test_ptr], fuzzing_mask[test_ptr], test_ptr, fuzzing_mask);
      return -1;
      break;
    }

    if (do_it && do_fuzz) {
      if (test_current >= test_start && test_current <= test_end && do_fuzz) {

        // Generate new transaction id
        if (xid == 0) {
          int three_byte_test_current = test_current % 0x1000000;

          memcpy(hdr->pkt + 63, (char *) &three_byte_test_current, 3);

        }
        // Regenerate UDP checksum 
        hdr->pkt[60] = 0;
        hdr->pkt[61] = 0;
        i = checksum_pseudo_header(hdr->original_src, hdr->final_dst, NXT_UDP, &hdr->pkt[54], hdr->pkt_len - 54);
        hdr->pkt[60] = i / 256;
        hdr->pkt[61] = i % 256;

        // send packets
        int k;

        for (k = 0; k < no_send; k++) {
          if (fdebug)
            fprintf(stderr, "send it\n");
          while (thc_send_pkt(interface, pkt, pkt_len) < 0)
            usleep(1);
        }
        // printf(".");
        usleep(250);
        ++f_cnt;

      }
      // reset to basic packet
      memcpy(hdr->pkt, pkt_bak, hdr->pkt_len);
      test_current++;
    }
  }
}

void dhcpc_listener() {
  if ((s = thc_bind_udp_port(547)) < 0) {
    fprintf(stderr, "Error: could not bind to 547/udp\n");
    exit(-1);
  }
  if (thc_bind_multicast_to_socket(s, interface, thc_resolve6("ff02::1:2")) < 0) {
    fprintf(stderr, "Error: could not bind multicast address\n");
    exit(-1);
  }
  if ((t = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
    perror("Error:");
    exit(-1);
  }

  if (p_cnt > 0) {
    printf("%d messages sent\n", p_cnt);
    p_cnt = 0;
  }
  printf("\nListening for DHCPv6 clients on %s (Press Control-C to end) ...\n\n", interface);
  while (1) {
    memset((char *) &from, 0, sizeof(from));
    memset(&iov, 0, sizeof(iov));
    memset(&mhdr, 0, sizeof(mhdr));
    iov.iov_base = rdatabuf;
    iov.iov_len = sizeof(rdatabuf);
    mhdr.msg_name = &from;
    mhdr.msg_namelen = sizeof(from);
    mhdr.msg_iov = &iov;
    mhdr.msg_iovlen = 1;
    mhdr.msg_control = (caddr_t) cmsgbuf;
    mhdr.msg_controllen = sizeof(cmsgbuf);
    if ((len = recvmsg(s, &mhdr, 0)) > 0) {
      fromlen = mhdr.msg_namelen;
      if (fdebug)
        thc_dump_data(rdatabuf, len, "Received Packet");
      ddst.sin6_addr = ((struct sockaddr_in6 *) mhdr.msg_name)->sin6_addr;
      ptr2 = thc_ipv62notation((char *) &ddst.sin6_addr);
      printf("\nReceived DHCPv6 Type %d message from %s\n", rdatabuf[0], ptr2);
      strncpy((char *) &victim, ptr2, sizeof(victim));
      free(ptr2);
      dst = thc_resolve6(victim);
      /* get xid and cid */
      tribyte_id[2] = rdatabuf[1];
      tribyte_id[1] = rdatabuf[2];
      tribyte_id[0] = rdatabuf[3];
      printf("Transaction ID: %x%x%x\n", rdatabuf[1], rdatabuf[2], rdatabuf[3]);
      xid = 1;
      int roffset = 5;

      while (roffset < len) {
        if (rdatabuf[roffset] != 1) {
          /* skip option */
          if (fdebug)
            printf("%d option %d length %d\n", roffset, (int) rdatabuf[roffset], (int) rdatabuf[roffset + 2]);
          roffset += (int) rdatabuf[roffset + 2];
          roffset += 4;
          continue;
        }
        if (rdatabuf[roffset + 4] != 1) {
          fprintf(stderr, "Can only reply to clients using DUID Type 1\n");
          break;
        }
        if (rdatabuf[roffset + 3] == 0x00 && rdatabuf[roffset + 4] == 0x01) {
          cidflag = 1;
          memcpy(cid, &rdatabuf[roffset + 3], 14);
          if (fdebug)
            printf("got it!\n");
          break;
        }
      }
      printf("Client ID: %02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x\n", cid[0], cid[1], cid[2], cid[3], cid[4], cid[5], cid[6], cid[7], cid[8], cid[9], cid[10],
             cid[11], cid[12], cid[13]);
      if (oflg)
        printf("Options: %s\n", option_string);
      printf("\nFields Fuzzed:\n\n");
      do_fuzzer();
      printf("\n\nListening for DHCPv6 clients on %s (Press Control-C to end) ...\n\n", interface);
      f_cnt = 0;
    }                           /* Received */
  }                             /* while */
}

int main(int argc, char *argv[]) {
  if (argc < 2 || strncmp(argv[1], "-h", 2) == 0)
    help(argv[0]);

  if (getenv("THC_IPV6_PPPOE") != NULL || getenv("THC_IPV6_6IN4") != NULL)
    printf("WARNING: %s is not working with injection!\n", argv[0]);

  //Parse options
  memset(cid, 0, 14);           /* clear cid */
  while ((i = getopt(argc, argv, "123456789ABCDmn:t:e:T:dlp:frv:x:c:o:")) >= 0) {
    switch (i) {
    case '1':
      do_type = DO_SOL;
      break;
    case '2':
      do_type = DO_ADV;
      break;
    case '3':
      do_type = DO_REQ;
      break;
    case '4':
      do_type = DO_CON;
      break;
    case '5':
      do_type = DO_REN;
      break;
    case '6':
      do_type = DO_REB;
      break;
    case '7':
      do_type = DO_REP;
      break;
    case '8':
      do_type = DO_REL;
      break;
    case '9':
      do_type = DO_DEC;
      break;
    case 'A':
      do_type = DO_REC;
      break;
    case 'B':
      do_type = DO_NFO;
      break;
    case 'C':
      do_type = DO_REL_FOR;
      break;
    case 'D':
      do_type = DO_REL_REP;
      break;
    case 'm':
      fuzz_dhcp_msg = 1;
      break;
    case 'n':
      no_send = atoi(optarg);
      break;
    case 't':
      test_start = atoi(optarg);
      break;
    case 'e':
      test_end = atoi(optarg);
      break;
    case 'T':
      test_end = test_start = atoi(optarg);
      break;
    case 'l':
      use_real_link = 0;        // no break
    case 'f':
      use_real_mac = 0;
      break;
    case 'p':
      ping = atoi(optarg);
      break;
    case 'd':
      fdebug = 1;
    case 'r':
      i = 0;
      break;                    // just to ignore -r
    case 'v':
      strncpy((char *) &victim, optarg, sizeof(victim));
      listen_for_clients = 0;
      break;
    case 'o':
      oflg = 1;
      strncpy((char *) &option_string, optarg, sizeof(option_string));
      break;
    case 'x':
      sscanf(optarg, "%x", &xid);
      break;
    case 'c':
      cidflag = 1;
      sscanf(optarg, "%2x%2x%2x%2x%2x%2x%2x%2x%2x%2x%2x%2x%2x%2x", (char *) &cid[0], (char *) &cid[1], (char *) &cid[2], (char *) &cid[3], (char *) &cid[4], (char *) &cid[5],
             (char *) &cid[6], (char *) &cid[7], (char *) &cid[8], (char *) &cid[9], (char *) &cid[10], (char *) &cid[11], (char *) &cid[12], (char *) &cid[13]);
      break;
    default:
      fprintf(stderr, "Error: unknown option -%c\n", i);
      exit(-1);
    }
  }

  //Check options
  if (no_send < 1) {
    fprintf(stderr, "ERROR: -n number must be between one and 2 billion\n");
    exit(-1);
  }

  if (test_end < test_start) {
    printf("don't fuck up the command line options!\n");
    exit(-1);
  }

  memset(mac, 0, sizeof(mac));
  interface = argv[optind];
  if (interface == NULL) {
    fprintf(stderr, "interface required\n");
    exit(0);
  }
  if (use_real_link)
    src = thc_get_own_ipv6(interface, NULL, PREFER_LINK);
  else
    src = thc_resolve6("fe80::");
  if (use_real_mac) {
    mac6 = thc_get_own_mac(interface);
    memcpy(mac, mac6, sizeof(mac));
  }
  setvbuf(stdout, NULL, _IONBF, 0);
  setvbuf(stderr, NULL, _IONBF, 0);
  if (listen_for_clients)
    dhcpc_listener();
  else
    dst = thc_resolve6(victim);

  // only to prevent our system to send icmp port unreachable messages
  if ((s = thc_bind_udp_port(547)) < 0)
    fprintf(stderr, "Warning: could not bind to 547/udp\n");
  if ((p = thc_pcap_init_promisc(interface, "ip6 and udp and dst port 547")) == NULL) {
    fprintf(stderr, "Error: can not open interface %s in promisc mode\n", interface);
    exit(-1);
  }
  printf("\nVictim: %s\n", victim);
  if (xid)
    printf("Transaction ID: %x\n", xid);
  if (cidflag)
    printf("Client ID: %02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x\n", cid[0], cid[1], cid[2], cid[3], cid[4], cid[5], cid[6], cid[7], cid[8], cid[9], cid[10],
           cid[11], cid[12], cid[13]);
  if (oflg)
    printf("Options: %s\n", option_string);
  printf("\nFields Fuzzed:\n\n");
  do_fuzzer();
}

int do_fuzzer() {
  char *ptr;

  int bad_length = 0;

  // Generate fuzzing mask and packet
  memset((char *) &fuzzing_mask, 0, 256);       /* clear fuzzing mask */
  memset((char *) &wdatabuf, 0, 1024);  /* clear message buffer */

  strcat(fuzzing_mask, mac_fuzz);       /* Don't fuzz MAC */
  strcat(fuzzing_mask, ipv6_fuzz);      /* Don't fuzz target IPv6 address */
  strcat(fuzzing_mask, udp_header_fuzz);        /* Don't fuzz UDP header */

  if (fuzz_dhcp_msg == 0) {
    options[0].code[0] = do_type;
    strcat(fuzzing_mask, options[0].dont_fuzz);
  } else
    strcat(fuzzing_mask, options[0].fuzz);
  wdatabuf[0] = options[0].code[0];
  // Transaction ID
  if (xid > 0) {
    if (listen_for_clients == 0)
      memcpy(tribyte_id, (char *) &xid, 3);
    options[1].code[0] = tribyte_id[2];
    options[1].code[1] = tribyte_id[1];
    options[1].code[2] = tribyte_id[0];
    strcat(fuzzing_mask, options[1].dont_fuzz);
  } else
    strcat(fuzzing_mask, options[1].fuzz);
  memcpy((char *) &wdatabuf[1], options[1].code, options[1].length);


  // Load client ID
  memcpy((char *) &options[2].code[4], cid, 14);
  if (cidflag == 0)
    strcat(fuzzing_mask, options[2].fuzz);
  else
    strcat(fuzzing_mask, options[2].dont_fuzz);
  memcpy((char *) &wdatabuf[4], options[2].code, options[2].length);

  // Insert time stamp and MAC in Server ID option
  double secs;

  secs = time(NULL);
  memcpy((char *) &options[3].code[8], (char *) &secs, 4);      /* time stamp */
  memcpy((char *) &options[3].code[12], thc_get_own_mac(interface), 6);
  int optx = 0;
  int opt_off = 22;

  ptr = option_string;
  while (*ptr) {
    if (*ptr < 'a' || *ptr > 'r') {
      ++ptr;
      continue;
    }
    if (*ptr == 'L') {
      bad_length = 1;
      ++ptr;
      continue;
    }
    for (optx = 0; optx < 21; optx++)
      if (*ptr == options[optx].tag)
        break;
    if (bad_length) {
      options[optx].fuzz[2] = 'B';
      options[optx].fuzz[3] = 'B';
      bad_length = 0;
    }
    strcat(fuzzing_mask, options[optx].fuzz);

    memcpy((char *) &wdatabuf[opt_off], options[optx].code, options[optx].length);
    opt_off += options[optx].length;
    ++ptr;
  }
  if (fdebug)
    printf("%s\n", fuzzing_mask);

  if (!use_real_link)
    for (i = 0; i < 8; i++)
      src[i + 8] = rand() % 256;

  if (!use_real_mac) {
    mac[i * 2] = rand() % 256;
    mac[i * 2 + 1] = rand() % 256;
  }

  if ((pkt = thc_create_ipv6_extended(interface, PREFER_LINK, &pkt_len, src, dst, 1, 0, 0, 0, 0)) == NULL) {
    fprintf(stderr, "Can't create IPv6 Extended\n");
    return -1;
  }
  if (thc_add_udp(pkt, &pkt_len, 547, 546, 0, wdatabuf, opt_off) < 0) {
    fprintf(stderr, "Can't add UDP\n");
    return -1;
  }

  if (thc_generate_pkt(interface, mac6, NULL, pkt, &pkt_len) < 0) {
    fprintf(stderr, "Can't generate packet\n");
    return -1;
  }
  // Fuzz DHCPv6 Messgage and Send It
  if (fuzz_loop(pkt, &pkt_len) < 0)
    return -1;

  pkt = thc_destroy_packet(pkt);
  return 0;
}