// https://syzkaller.appspot.com/bug?id=3983f8a8d83851a54a0b9f9e75cb3464e9c70aef
// autogenerated by syzkaller (http://github.com/google/syzkaller)

#define _GNU_SOURCE

#include <arpa/inet.h>
#include <errno.h>
#include <fcntl.h>
#include <fcntl.h>
#include <linux/if.h>
#include <linux/if_ether.h>
#include <linux/if_tun.h>
#include <linux/ip.h>
#include <linux/tcp.h>
#include <net/if_arp.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/uio.h>
#include <unistd.h>

__attribute__((noreturn)) static void doexit(int status)
{
  volatile unsigned i;
  syscall(__NR_exit_group, status);
  for (i = 0;; i++) {
  }
}

#include <errno.h>
#include <setjmp.h>
#include <signal.h>
#include <stdarg.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <string.h>
#include <sys/stat.h>

const int kFailStatus = 67;
const int kRetryStatus = 69;

static void fail(const char* msg, ...)
{
  int e = errno;
  va_list args;
  va_start(args, msg);
  vfprintf(stderr, msg, args);
  va_end(args);
  fprintf(stderr, " (errno %d)\n", e);
  doexit((e == ENOMEM || e == EAGAIN) ? kRetryStatus : kFailStatus);
}

#define BITMASK_LEN(type, bf_len) (type)((1ull << (bf_len)) - 1)

#define BITMASK_LEN_OFF(type, bf_off, bf_len)                          \
  (type)(BITMASK_LEN(type, (bf_len)) << (bf_off))

#define STORE_BY_BITMASK(type, addr, val, bf_off, bf_len)              \
  if ((bf_off) == 0 && (bf_len) == 0) {                                \
    *(type*)(addr) = (type)(val);                                      \
  } else {                                                             \
    type new_val = *(type*)(addr);                                     \
    new_val &= ~BITMASK_LEN_OFF(type, (bf_off), (bf_len));             \
    new_val |= ((type)(val)&BITMASK_LEN(type, (bf_len))) << (bf_off);  \
    *(type*)(addr) = new_val;                                          \
  }

struct csum_inet {
  uint32_t acc;
};

static void csum_inet_init(struct csum_inet* csum)
{
  csum->acc = 0;
}

static void csum_inet_update(struct csum_inet* csum,
                             const uint8_t* data, size_t length)
{
  if (length == 0)
    return;

  size_t i;
  for (i = 0; i < length - 1; i += 2)
    csum->acc += *(uint16_t*)&data[i];

  if (length & 1)
    csum->acc += (uint16_t)data[length - 1];

  while (csum->acc > 0xffff)
    csum->acc = (csum->acc & 0xffff) + (csum->acc >> 16);
}

static uint16_t csum_inet_digest(struct csum_inet* csum)
{
  return ~csum->acc;
}

static __thread int skip_segv;
static __thread jmp_buf segv_env;

static void segv_handler(int sig, siginfo_t* info, void* uctx)
{
  uintptr_t addr = (uintptr_t)info->si_addr;
  const uintptr_t prog_start = 1 << 20;
  const uintptr_t prog_end = 100 << 20;
  if (__atomic_load_n(&skip_segv, __ATOMIC_RELAXED) &&
      (addr < prog_start || addr > prog_end)) {
    _longjmp(segv_env, 1);
  }
  doexit(sig);
  for (;;) {
  }
}

static void install_segv_handler()
{
  struct sigaction sa;

  memset(&sa, 0, sizeof(sa));
  sa.sa_handler = SIG_IGN;
  syscall(SYS_rt_sigaction, 0x20, &sa, NULL, 8);
  syscall(SYS_rt_sigaction, 0x21, &sa, NULL, 8);

  memset(&sa, 0, sizeof(sa));
  sa.sa_sigaction = segv_handler;
  sa.sa_flags = SA_NODEFER | SA_SIGINFO;
  sigaction(SIGSEGV, &sa, NULL);
  sigaction(SIGBUS, &sa, NULL);
}

#define NONFAILING(...)                                                \
  {                                                                    \
    __atomic_fetch_add(&skip_segv, 1, __ATOMIC_SEQ_CST);               \
    if (_setjmp(segv_env) == 0) {                                      \
      __VA_ARGS__;                                                     \
    }                                                                  \
    __atomic_fetch_sub(&skip_segv, 1, __ATOMIC_SEQ_CST);               \
  }

static void use_temporary_dir()
{
  char tmpdir_template[] = "./syzkaller.XXXXXX";
  char* tmpdir = mkdtemp(tmpdir_template);
  if (!tmpdir)
    fail("failed to mkdtemp");
  if (chmod(tmpdir, 0777))
    fail("failed to chmod");
  if (chdir(tmpdir))
    fail("failed to chdir");
}

static void vsnprintf_check(char* str, size_t size, const char* format,
                            va_list args)
{
  int rv;

  rv = vsnprintf(str, size, format, args);
  if (rv < 0)
    fail("tun: snprintf failed");
  if ((size_t)rv >= size)
    fail("tun: string '%s...' doesn't fit into buffer", str);
}

static void snprintf_check(char* str, size_t size, const char* format,
                           ...)
{
  va_list args;

  va_start(args, format);
  vsnprintf_check(str, size, format, args);
  va_end(args);
}

#define COMMAND_MAX_LEN 128
#define PATH_PREFIX                                                    \
  "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin "
#define PATH_PREFIX_LEN (sizeof(PATH_PREFIX) - 1)

static void execute_command(const char* format, ...)
{
  va_list args;
  char command[PATH_PREFIX_LEN + COMMAND_MAX_LEN];
  int rv;

  va_start(args, format);
  memcpy(command, PATH_PREFIX, PATH_PREFIX_LEN);
  vsnprintf_check(command + PATH_PREFIX_LEN, COMMAND_MAX_LEN, format,
                  args);
  rv = system(command);
  if (rv != 0)
    fail("tun: command \"%s\" failed with code %d", &command[0], rv);

  va_end(args);
}

static int tunfd = -1;
static int tun_frags_enabled;

#define SYZ_TUN_MAX_PACKET_SIZE 1000

#define MAX_PIDS 32
#define ADDR_MAX_LEN 32

#define LOCAL_MAC "aa:aa:aa:aa:aa:%02hx"
#define REMOTE_MAC "bb:bb:bb:bb:bb:%02hx"

#define LOCAL_IPV4 "172.20.%d.170"
#define REMOTE_IPV4 "172.20.%d.187"

#define LOCAL_IPV6 "fe80::%02hxaa"
#define REMOTE_IPV6 "fe80::%02hxbb"

#define IFF_NAPI 0x0010
#define IFF_NAPI_FRAGS 0x0020

static void initialize_tun(uint64_t pid)
{
  if (pid >= MAX_PIDS)
    fail("tun: no more than %d executors", MAX_PIDS);
  int id = pid;

  tunfd = open("/dev/net/tun", O_RDWR | O_NONBLOCK);
  if (tunfd == -1)
    fail("tun: can't open /dev/net/tun");

  char iface[IFNAMSIZ];
  snprintf_check(iface, sizeof(iface), "syz%d", id);

  struct ifreq ifr;
  memset(&ifr, 0, sizeof(ifr));
  strncpy(ifr.ifr_name, iface, IFNAMSIZ);
  ifr.ifr_flags = IFF_TAP | IFF_NO_PI | IFF_NAPI | IFF_NAPI_FRAGS;
  if (ioctl(tunfd, TUNSETIFF, (void*)&ifr) < 0) {
    ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
    if (ioctl(tunfd, TUNSETIFF, (void*)&ifr) < 0)
      fail("tun: ioctl(TUNSETIFF) failed");
  }
  if (ioctl(tunfd, TUNGETIFF, (void*)&ifr) < 0)
    fail("tun: ioctl(TUNGETIFF) failed");
  tun_frags_enabled = (ifr.ifr_flags & IFF_NAPI_FRAGS) != 0;

  char local_mac[ADDR_MAX_LEN];
  snprintf_check(local_mac, sizeof(local_mac), LOCAL_MAC, id);
  char remote_mac[ADDR_MAX_LEN];
  snprintf_check(remote_mac, sizeof(remote_mac), REMOTE_MAC, id);

  char local_ipv4[ADDR_MAX_LEN];
  snprintf_check(local_ipv4, sizeof(local_ipv4), LOCAL_IPV4, id);
  char remote_ipv4[ADDR_MAX_LEN];
  snprintf_check(remote_ipv4, sizeof(remote_ipv4), REMOTE_IPV4, id);

  char local_ipv6[ADDR_MAX_LEN];
  snprintf_check(local_ipv6, sizeof(local_ipv6), LOCAL_IPV6, id);
  char remote_ipv6[ADDR_MAX_LEN];
  snprintf_check(remote_ipv6, sizeof(remote_ipv6), REMOTE_IPV6, id);

  execute_command("sysctl -w net.ipv6.conf.%s.accept_dad=0", iface);

  execute_command("sysctl -w net.ipv6.conf.%s.router_solicitations=0",
                  iface);

  execute_command("ip link set dev %s address %s", iface, local_mac);
  execute_command("ip addr add %s/24 dev %s", local_ipv4, iface);
  execute_command("ip -6 addr add %s/120 dev %s", local_ipv6, iface);
  execute_command("ip neigh add %s lladdr %s dev %s nud permanent",
                  remote_ipv4, remote_mac, iface);
  execute_command("ip -6 neigh add %s lladdr %s dev %s nud permanent",
                  remote_ipv6, remote_mac, iface);
  execute_command("ip link set dev %s up", iface);
}

static void setup_tun(uint64_t pid, bool enable_tun)
{
  if (enable_tun)
    initialize_tun(pid);
}

static uintptr_t syz_open_dev(uintptr_t a0, uintptr_t a1, uintptr_t a2)
{
  if (a0 == 0xc || a0 == 0xb) {
    char buf[128];
    sprintf(buf, "/dev/%s/%d:%d", a0 == 0xc ? "char" : "block",
            (uint8_t)a1, (uint8_t)a2);
    return open(buf, O_RDWR, 0);
  } else {
    char buf[1024];
    char* hash;
    NONFAILING(strncpy(buf, (char*)a0, sizeof(buf)));
    buf[sizeof(buf) - 1] = 0;
    while ((hash = strchr(buf, '#'))) {
      *hash = '0' + (char)(a1 % 10);
      a1 /= 10;
    }
    return open(buf, a2, 0);
  }
}

long r[73];
void loop()
{
  memset(r, -1, sizeof(r));
  r[0] = syscall(__NR_mmap, 0x20000000ul, 0xfff000ul, 0x3ul, 0x32ul,
                 0xfffffffffffffffful, 0x0ul);
  r[1] = syscall(__NR_socket, 0x2ul, 0x1ul, 0x0ul);
  NONFAILING(memcpy(
      (void*)0x2051fff3,
      "\x2f\x64\x65\x76\x2f\x6e\x65\x74\x2f\x74\x75\x6e\x00", 13));
  r[3] = syz_open_dev(0x2051fff3ul, 0x0ul, 0xaul);
  r[4] = syscall(__NR_fcntl, r[3], 0x0ul, r[3]);
  NONFAILING(memcpy((void*)0x20a5afd8, "\x67\x72\x65\x30\x00\x00\x00"
                                       "\x00\x00\x00\x00\x00\x00\x00"
                                       "\x00\x00",
                    16));
  NONFAILING(memcpy((void*)0x20a5afe8, "\x4f\x54\x00\x0c\xc0\xa1\xed"
                                       "\x4f\x3a\x0a\x1f\xdc\x22\x20"
                                       "\x73\xb5",
                    16));
  r[7] = syscall(__NR_ioctl, r[3], 0x400454caul, 0x20a5afd8ul);
  NONFAILING(memcpy((void*)0x2062ffe0, "\x67\x72\x65\x30\x00\x00\x00"
                                       "\x00\x00\x00\x00\x00\x00\x00"
                                       "\x00\x00",
                    16));
  NONFAILING(*(uint16_t*)0x2062fff0 = (uint16_t)0x301);
  r[10] = syscall(__NR_ioctl, r[1], 0x8914ul, 0x2062ffe0ul);
  r[11] = syscall(__NR_socket, 0xaul, 0x1ul, 0x0ul);
  NONFAILING(*(uint32_t*)0x20e9bffc = (uint32_t)0xfffffffffffffffc);
  r[13] = syscall(__NR_ioctl, r[3], 0x400454d4ul, 0x20e9bffcul);
  NONFAILING(*(uint8_t*)0x20101000 = (uint8_t)0x0);
  NONFAILING(*(uint8_t*)0x20101001 = (uint8_t)0x0);
  NONFAILING(*(uint16_t*)0x20101002 = (uint16_t)0x0);
  NONFAILING(*(uint16_t*)0x20101004 = (uint16_t)0x0);
  NONFAILING(*(uint16_t*)0x20101006 = (uint16_t)0x0);
  NONFAILING(*(uint16_t*)0x20101008 = (uint16_t)0x0);
  NONFAILING(STORE_BY_BITMASK(uint8_t, 0x2010100a, 0x0, 0, 4));
  NONFAILING(STORE_BY_BITMASK(uint8_t, 0x2010100a, 0x6, 4, 4));
  NONFAILING(memcpy((void*)0x2010100b, "\x85\xb7\xe3", 3));
  NONFAILING(*(uint16_t*)0x2010100e = (uint16_t)0x1400);
  NONFAILING(*(uint8_t*)0x20101010 = (uint8_t)0x6);
  NONFAILING(*(uint8_t*)0x20101011 = (uint8_t)0x0);
  NONFAILING(*(uint8_t*)0x20101012 = (uint8_t)0xfe);
  NONFAILING(*(uint8_t*)0x20101013 = (uint8_t)0x80);
  NONFAILING(*(uint8_t*)0x20101014 = (uint8_t)0x0);
  NONFAILING(*(uint8_t*)0x20101015 = (uint8_t)0x0);
  NONFAILING(*(uint8_t*)0x20101016 = (uint8_t)0x0);
  NONFAILING(*(uint8_t*)0x20101017 = (uint8_t)0x0);
  NONFAILING(*(uint8_t*)0x20101018 = (uint8_t)0x0);
  NONFAILING(*(uint8_t*)0x20101019 = (uint8_t)0x0);
  NONFAILING(*(uint8_t*)0x2010101a = (uint8_t)0x0);
  NONFAILING(*(uint8_t*)0x2010101b = (uint8_t)0x0);
  NONFAILING(*(uint8_t*)0x2010101c = (uint8_t)0x0);
  NONFAILING(*(uint8_t*)0x2010101d = (uint8_t)0x0);
  NONFAILING(*(uint8_t*)0x2010101e = (uint8_t)0x0);
  NONFAILING(*(uint8_t*)0x2010101f = (uint8_t)0x0);
  NONFAILING(*(uint8_t*)0x20101020 = (uint8_t)0x0);
  NONFAILING(*(uint8_t*)0x20101021 = (uint8_t)0xbb);
  NONFAILING(*(uint8_t*)0x20101022 = (uint8_t)0xfe);
  NONFAILING(*(uint8_t*)0x20101023 = (uint8_t)0x80);
  NONFAILING(*(uint8_t*)0x20101024 = (uint8_t)0x0);
  NONFAILING(*(uint8_t*)0x20101025 = (uint8_t)0x0);
  NONFAILING(*(uint8_t*)0x20101026 = (uint8_t)0x0);
  NONFAILING(*(uint8_t*)0x20101027 = (uint8_t)0x0);
  NONFAILING(*(uint8_t*)0x20101028 = (uint8_t)0x0);
  NONFAILING(*(uint8_t*)0x20101029 = (uint8_t)0x0);
  NONFAILING(*(uint8_t*)0x2010102a = (uint8_t)0x0);
  NONFAILING(*(uint8_t*)0x2010102b = (uint8_t)0x0);
  NONFAILING(*(uint8_t*)0x2010102c = (uint8_t)0x0);
  NONFAILING(*(uint8_t*)0x2010102d = (uint8_t)0x0);
  NONFAILING(*(uint8_t*)0x2010102e = (uint8_t)0x0);
  NONFAILING(*(uint8_t*)0x2010102f = (uint8_t)0x0);
  NONFAILING(*(uint8_t*)0x20101030 = (uint8_t)0x0);
  NONFAILING(*(uint8_t*)0x20101031 = (uint8_t)0xbb);
  NONFAILING(*(uint16_t*)0x20101032 = (uint16_t)0x204e);
  NONFAILING(*(uint16_t*)0x20101034 = (uint16_t)0x204e);
  NONFAILING(*(uint32_t*)0x20101036 = (uint32_t)0x42424242);
  NONFAILING(*(uint32_t*)0x2010103a = (uint32_t)0x42424242);
  NONFAILING(STORE_BY_BITMASK(uint8_t, 0x2010103e, 0x0, 0, 1));
  NONFAILING(STORE_BY_BITMASK(uint8_t, 0x2010103e, 0x0, 1, 3));
  NONFAILING(STORE_BY_BITMASK(uint8_t, 0x2010103e, 0x5, 4, 4));
  NONFAILING(*(uint8_t*)0x2010103f = (uint8_t)0x0);
  NONFAILING(*(uint16_t*)0x20101040 = (uint16_t)0x0);
  NONFAILING(*(uint16_t*)0x20101042 = (uint16_t)0x0);
  NONFAILING(*(uint16_t*)0x20101044 = (uint16_t)0x0);
  struct csum_inet csum_69;
  csum_inet_init(&csum_69);
  NONFAILING(
      csum_inet_update(&csum_69, (const uint8_t*)0x20101012, 16));
  NONFAILING(
      csum_inet_update(&csum_69, (const uint8_t*)0x20101022, 16));
  uint32_t csum_69_chunk_2 = 0x14000000;
  csum_inet_update(&csum_69, (const uint8_t*)&csum_69_chunk_2, 4);
  uint32_t csum_69_chunk_3 = 0x6000000;
  csum_inet_update(&csum_69, (const uint8_t*)&csum_69_chunk_3, 4);
  NONFAILING(
      csum_inet_update(&csum_69, (const uint8_t*)0x20101032, 20));
  NONFAILING(*(uint16_t*)0x20101042 = csum_inet_digest(&csum_69));
  r[70] = syscall(__NR_write, r[4], 0x20101000ul, 0x46ul);
  NONFAILING(memcpy((void*)0x201ab000, "\x69\x66\x62\x30\x00\x00\x00"
                                       "\x00\x00\x00\x00\x00\x00\x00"
                                       "\x00\x00",
                    16));
  r[72] =
      syscall(__NR_ioctl, 0xfffffffffffffffful, 0x89a0ul, 0x201ab000ul);
}

int main()
{
  install_segv_handler();
  use_temporary_dir();
  setup_tun(0, true);
  loop();
  return 0;
}