// https://syzkaller.appspot.com/bug?id=17a06459ecad660a3d00c3e41a4b1a7be6bca19e
// 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 <pthread.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdlib.h>
#include <sys/ioctl.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 <setjmp.h>
#include <signal.h>
#include <stdint.h>
#include <string.h>
#include <string.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);
}

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 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) {
    printf(
        "tun: can't open /dev/net/tun: please enable CONFIG_TUN=y\n");
    printf("otherwise fuzzing or reproducing might not work as "
           "intended\n");
    return;
  }

  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_pts(uintptr_t a0, uintptr_t a1)
{
  int ptyno = 0;
  if (ioctl(a0, TIOCGPTN, &ptyno))
    return -1;
  char buf[128];
  sprintf(buf, "/dev/pts/%d", ptyno);
  return open(buf, a1, 0);
}

#ifndef __NR_memfd_create
#define __NR_memfd_create 319
#endif

long r[4];
void* thr(void* arg)
{
  switch ((long)arg) {
  case 0:
    syscall(__NR_mmap, 0x20000000ul, 0xfdf000ul, 0x3ul, 0x32ul,
            0xfffffffffffffffful, 0x0ul);
    break;
  case 1:
    NONFAILING(memcpy((void*)0x20960000, "/dev/ptmx", 10));
    r[0] = syscall(__NR_openat, 0xffffffffffffff9cul, 0x20960000ul,
                   0x0ul, 0x0ul);
    break;
  case 2:
    NONFAILING(memcpy((void*)0x20fdbff7, "^keyring", 9));
    r[1] = syscall(__NR_memfd_create, 0x20fdbff7ul, 0x2ul);
    break;
  case 3:
    NONFAILING(memcpy((void*)0x20375000, "/dev/autofs", 12));
    r[2] = syscall(__NR_openat, 0xffffffffffffff9cul, 0x20375000ul,
                   0x4000ul, 0x0ul);
    break;
  case 4:
    NONFAILING(*(uint32_t*)0x20fdb000 = (uint32_t)0x0);
    NONFAILING(*(uint32_t*)0x20fdb004 = (uint32_t)0x0);
    NONFAILING(*(uint32_t*)0x2070cffc = (uint32_t)0x8);
    syscall(__NR_getsockopt, r[2], 0x84ul, 0x6dul, 0x20fdb000ul,
            0x2070cffcul);
    break;
  case 5:
    NONFAILING(*(uint16_t*)0x20fd6000 = (uint16_t)0x0);
    NONFAILING(*(uint16_t*)0x20fd6002 = (uint16_t)0x0);
    NONFAILING(*(uint16_t*)0x20fd6004 = (uint16_t)0x0);
    NONFAILING(*(uint16_t*)0x20fd6006 = (uint16_t)0x0);
    NONFAILING(*(uint8_t*)0x20fd6008 = (uint8_t)0x0);
    NONFAILING(*(uint8_t*)0x20fd6009 = (uint8_t)0x3fd);
    NONFAILING(*(uint8_t*)0x20fd600a = (uint8_t)0x0);
    NONFAILING(*(uint8_t*)0x20fd600b = (uint8_t)0x0);
    NONFAILING(*(uint32_t*)0x20fd600c = (uint32_t)0xffffffff);
    NONFAILING(*(uint8_t*)0x20fd6010 = (uint8_t)0xfff);
    syscall(__NR_ioctl, r[0], 0x5402ul, 0x20fd6000ul);
    break;
  case 6:
    NONFAILING(*(uint32_t*)0x20fdcf88 = (uint32_t)0x5);
    NONFAILING(*(uint32_t*)0x20fdcf8c = (uint32_t)0x78);
    NONFAILING(*(uint8_t*)0x20fdcf90 = (uint8_t)0xffffffffffffff81);
    NONFAILING(*(uint8_t*)0x20fdcf91 = (uint8_t)0x1f);
    NONFAILING(*(uint8_t*)0x20fdcf92 = (uint8_t)0x100000000);
    NONFAILING(*(uint8_t*)0x20fdcf93 = (uint8_t)0xffffffff);
    NONFAILING(*(uint32_t*)0x20fdcf94 = (uint32_t)0x0);
    NONFAILING(*(uint64_t*)0x20fdcf98 = (uint64_t)0xfff);
    NONFAILING(*(uint64_t*)0x20fdcfa0 = (uint64_t)0x10000);
    NONFAILING(*(uint64_t*)0x20fdcfa8 = (uint64_t)0x2);
    NONFAILING(*(uint8_t*)0x20fdcfb0 = (uint8_t)0x4);
    NONFAILING(*(uint8_t*)0x20fdcfb1 = (uint8_t)0x100);
    NONFAILING(*(uint8_t*)0x20fdcfb2 = (uint8_t)0x9);
    NONFAILING(*(uint8_t*)0x20fdcfb3 = (uint8_t)0x4);
    NONFAILING(*(uint32_t*)0x20fdcfb4 = (uint32_t)0x0);
    NONFAILING(*(uint32_t*)0x20fdcfb8 = (uint32_t)0x80);
    NONFAILING(*(uint32_t*)0x20fdcfbc = (uint32_t)0x2);
    NONFAILING(*(uint64_t*)0x20fdcfc0 = (uint64_t)0x3);
    NONFAILING(*(uint64_t*)0x20fdcfc8 = (uint64_t)0x6);
    NONFAILING(*(uint64_t*)0x20fdcfd0 = (uint64_t)0x2);
    NONFAILING(*(uint64_t*)0x20fdcfd8 = (uint64_t)0x4);
    NONFAILING(*(uint64_t*)0x20fdcfe0 = (uint64_t)0x24b);
    NONFAILING(*(uint32_t*)0x20fdcfe8 = (uint32_t)0x7);
    NONFAILING(*(uint64_t*)0x20fdcff0 = (uint64_t)0x80000001);
    NONFAILING(*(uint32_t*)0x20fdcff8 = (uint32_t)0x8);
    NONFAILING(*(uint16_t*)0x20fdcffc = (uint16_t)0xff);
    NONFAILING(*(uint16_t*)0x20fdcffe = (uint16_t)0x0);
    syscall(__NR_perf_event_open, 0x20fdcf88ul, 0x0ul, 0x2ul, r[1],
            0x5ul);
    break;
  case 7:
    NONFAILING(*(uint32_t*)0x203b9fdc = (uint32_t)0x0);
    NONFAILING(*(uint32_t*)0x203b9fe0 = (uint32_t)0x0);
    NONFAILING(*(uint32_t*)0x203b9fe4 = (uint32_t)0x0);
    NONFAILING(*(uint32_t*)0x203b9fe8 = (uint32_t)0x0);
    NONFAILING(*(uint8_t*)0x203b9fec = (uint8_t)0x0);
    NONFAILING(*(uint8_t*)0x203b9fed = (uint8_t)0x0);
    NONFAILING(*(uint8_t*)0x203b9fee = (uint8_t)0x0);
    NONFAILING(*(uint8_t*)0x203b9fef = (uint8_t)0x0);
    NONFAILING(*(uint32_t*)0x203b9ff0 = (uint32_t)0x0);
    NONFAILING(*(uint32_t*)0x203b9ff4 = (uint32_t)0x0);
    NONFAILING(*(uint32_t*)0x203b9ff8 = (uint32_t)0x0);
    NONFAILING(*(uint32_t*)0x203b9ffc = (uint32_t)0x0);
    syscall(__NR_ioctl, r[0], 0x40045431ul, 0x203b9fdcul);
    break;
  case 8:
    r[3] = syz_open_pts(r[0], 0x0ul);
    break;
  case 9:
    NONFAILING(*(uint64_t*)0x20fd6000 = (uint64_t)0x200c1f45);
    NONFAILING(*(uint64_t*)0x20fd6008 = (uint64_t)0xbb);
    NONFAILING(*(uint64_t*)0x20fd6010 = (uint64_t)0x20227fd0);
    NONFAILING(*(uint64_t*)0x20fd6018 = (uint64_t)0x30);
    NONFAILING(*(uint64_t*)0x20fd6020 = (uint64_t)0x20063000);
    NONFAILING(*(uint64_t*)0x20fd6028 = (uint64_t)0x7b);
    NONFAILING(*(uint64_t*)0x20fd6030 = (uint64_t)0x20313f29);
    NONFAILING(*(uint64_t*)0x20fd6038 = (uint64_t)0xd7);
    syscall(__NR_readv, r[3], 0x20fd6000ul, 0x4ul);
    break;
  case 10:
    syscall(__NR_ioctl, r[0], 0x540aul, 0x2ul);
    break;
  case 11:
    syscall(__NR_ioctl, r[3], 0x541bul, 0x20f76ffful);
    break;
  }
  return 0;
}

void loop()
{
  long i;
  pthread_t th[24];

  memset(r, -1, sizeof(r));
  for (i = 0; i < 12; i++) {
    pthread_create(&th[i], 0, thr, (void*)i);
    usleep(rand() % 10000);
  }
  usleep(rand() % 100000);
}

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