// https://syzkaller.appspot.com/bug?id=0bf841c341d12f2a41a9c84aca15d4620074f8c2
// autogenerated by syzkaller (http://github.com/google/syzkaller)

#ifndef __NR_bpf
#define __NR_bpf 321
#endif

#define _GNU_SOURCE

#include <arpa/inet.h>
#include <dirent.h>
#include <errno.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 <signal.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/mount.h>
#include <sys/prctl.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>

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

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

__attribute__((noreturn)) static void fail(const char* msg, ...)
{
  int e = errno;
  fflush(stdout);
  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);
}

__attribute__((noreturn)) static void exitf(const char* msg, ...)
{
  int e = errno;
  fflush(stdout);
  va_list args;
  va_start(args, msg);
  vfprintf(stderr, msg, args);
  va_end(args);
  fprintf(stderr, " (errno %d)\n", e);
  doexit(kRetryStatus);
}

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

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

  va_start(args, format);

  vsnprintf_check(command, sizeof(command), 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;

#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"

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;
  if (ioctl(tunfd, TUNSETIFF, (void*)&ifr) < 0)
    fail("tun: ioctl(TUNSETIFF) failed");

  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 int read_tun(char* data, int size)
{
  int rv = read(tunfd, data, size);
  if (rv < 0) {
    if (errno == EAGAIN)
      return -1;
    fail("tun: read failed with %d, errno: %d", rv, errno);
  }
  return rv;
}

static void flush_tun()
{
  char data[SYZ_TUN_MAX_PACKET_SIZE];
  while (read_tun(&data[0], sizeof(data)) != -1)
    ;
}

static void remove_dir(const char* dir)
{
  DIR* dp;
  struct dirent* ep;
  int iter = 0;
retry:
  dp = opendir(dir);
  if (dp == NULL) {
    if (errno == EMFILE) {
      exitf("opendir(%s) failed due to NOFILE, exiting");
    }
    exitf("opendir(%s) failed", dir);
  }
  while ((ep = readdir(dp))) {
    if (strcmp(ep->d_name, ".") == 0 || strcmp(ep->d_name, "..") == 0)
      continue;
    char filename[FILENAME_MAX];
    snprintf(filename, sizeof(filename), "%s/%s", dir, ep->d_name);
    struct stat st;
    if (lstat(filename, &st))
      exitf("lstat(%s) failed", filename);
    if (S_ISDIR(st.st_mode)) {
      remove_dir(filename);
      continue;
    }
    int i;
    for (i = 0;; i++) {
      if (unlink(filename) == 0)
        break;
      if (errno == EROFS) {
        break;
      }
      if (errno != EBUSY || i > 100)
        exitf("unlink(%s) failed", filename);
      if (umount2(filename, MNT_DETACH))
        exitf("umount(%s) failed", filename);
    }
  }
  closedir(dp);
  int i;
  for (i = 0;; i++) {
    if (rmdir(dir) == 0)
      break;
    if (i < 100) {
      if (errno == EROFS) {
        break;
      }
      if (errno == EBUSY) {
        if (umount2(dir, MNT_DETACH))
          exitf("umount(%s) failed", dir);
        continue;
      }
      if (errno == ENOTEMPTY) {
        if (iter < 100) {
          iter++;
          goto retry;
        }
      }
    }
    exitf("rmdir(%s) failed", dir);
  }
}

static uint64_t current_time_ms()
{
  struct timespec ts;

  if (clock_gettime(CLOCK_MONOTONIC, &ts))
    fail("clock_gettime failed");
  return (uint64_t)ts.tv_sec * 1000 + (uint64_t)ts.tv_nsec / 1000000;
}

static void test();

void loop()
{
  int iter;
  for (iter = 0;; iter++) {
    char cwdbuf[256];
    sprintf(cwdbuf, "./%d", iter);
    if (mkdir(cwdbuf, 0777))
      fail("failed to mkdir");
    int pid = fork();
    if (pid < 0)
      fail("clone failed");
    if (pid == 0) {
      prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
      setpgrp();
      if (chdir(cwdbuf))
        fail("failed to chdir");
      flush_tun();
      test();
      doexit(0);
    }
    int status = 0;
    uint64_t start = current_time_ms();
    for (;;) {
      int res = waitpid(-1, &status, __WALL | WNOHANG);
      if (res == pid)
        break;
      usleep(1000);
      if (current_time_ms() - start > 5 * 1000) {
        kill(-pid, SIGKILL);
        kill(pid, SIGKILL);
        while (waitpid(-1, &status, __WALL) != pid) {
        }
        break;
      }
    }
    remove_dir(cwdbuf);
  }
}

long r[67];
void* thr(void* arg)
{
  switch ((long)arg) {
  case 0:
    r[0] = syscall(__NR_mmap, 0x20000000ul, 0xfff000ul, 0x3ul, 0x32ul,
                   0xfffffffffffffffful, 0x0ul);
    break;
  case 1:
    r[1] = syscall(__NR_socket, 0x2ul, 0x1ul, 0x0ul);
    break;
  case 2:
    *(uint32_t*)0x20b4cfd0 = (uint32_t)0x1;
    *(uint32_t*)0x20b4cfd4 = (uint32_t)0x2;
    *(uint64_t*)0x20b4cfd8 = (uint64_t)0x20ef3000;
    *(uint64_t*)0x20b4cfe0 = (uint64_t)0x20b4d000;
    *(uint32_t*)0x20b4cfe8 = (uint32_t)0x1;
    *(uint32_t*)0x20b4cfec = (uint32_t)0x80;
    *(uint64_t*)0x20b4cff0 = (uint64_t)0x2000a000;
    *(uint32_t*)0x20b4cff8 = (uint32_t)0x0;
    *(uint32_t*)0x20b4cffc = (uint32_t)0x0;
    *(uint8_t*)0x20ef3000 = (uint8_t)0x8db7;
    *(uint8_t*)0x20ef3001 = (uint8_t)0x0;
    *(uint16_t*)0x20ef3002 = (uint16_t)0x0;
    *(uint32_t*)0x20ef3004 = (uint32_t)0x0;
    *(uint8_t*)0x20ef3008 = (uint8_t)0xd395;
    *(uint8_t*)0x20ef3009 = (uint8_t)0x0;
    *(uint16_t*)0x20ef300a = (uint16_t)0x0;
    *(uint32_t*)0x20ef300c = (uint32_t)0x0;
    memcpy((void*)0x20b4d000, "\x73\x79\x73\x65\x4f\x00", 6);
    r[20] = syscall(__NR_bpf, 0x5ul, 0x20b4cfd0ul, 0x30ul);
    break;
  case 3:
    r[21] = syscall(__NR_socket, 0x29ul, 0x5ul, 0x0ul);
    break;
  case 4:
    r[22] = syscall(__NR_write, r[21], 0x20efd000ul, 0x0ul);
    break;
  case 5:
    *(uint16_t*)0x20305ff0 = (uint16_t)0x2;
    *(uint16_t*)0x20305ff2 = (uint16_t)0x204e;
    *(uint32_t*)0x20305ff4 = (uint32_t)0x100;
    *(uint8_t*)0x20305ff8 = (uint8_t)0x0;
    *(uint8_t*)0x20305ff9 = (uint8_t)0x0;
    *(uint8_t*)0x20305ffa = (uint8_t)0x0;
    *(uint8_t*)0x20305ffb = (uint8_t)0x0;
    *(uint8_t*)0x20305ffc = (uint8_t)0x0;
    *(uint8_t*)0x20305ffd = (uint8_t)0x0;
    *(uint8_t*)0x20305ffe = (uint8_t)0x0;
    *(uint8_t*)0x20305fff = (uint8_t)0x0;
    r[34] = syscall(__NR_bind, r[1], 0x20305ff0ul, 0x10ul);
    break;
  case 6:
    *(uint32_t*)0x20efcff8 = r[1];
    *(uint32_t*)0x20efcffc = r[20];
    r[37] = syscall(__NR_ioctl, r[21], 0x89e0ul, 0x20efcff8ul);
    break;
  case 7:
    *(uint16_t*)0x20ef4000 = (uint16_t)0x2;
    *(uint16_t*)0x20ef4002 = (uint16_t)0x204e;
    *(uint8_t*)0x20ef4004 = (uint8_t)0xac;
    *(uint8_t*)0x20ef4005 = (uint8_t)0x14;
    *(uint8_t*)0x20ef4006 = (uint8_t)0x0;
    *(uint8_t*)0x20ef4007 = (uint8_t)0xaa;
    *(uint8_t*)0x20ef4008 = (uint8_t)0x0;
    *(uint8_t*)0x20ef4009 = (uint8_t)0x0;
    *(uint8_t*)0x20ef400a = (uint8_t)0x0;
    *(uint8_t*)0x20ef400b = (uint8_t)0x0;
    *(uint8_t*)0x20ef400c = (uint8_t)0x0;
    *(uint8_t*)0x20ef400d = (uint8_t)0x0;
    *(uint8_t*)0x20ef400e = (uint8_t)0x0;
    *(uint8_t*)0x20ef400f = (uint8_t)0x0;
    r[52] = syscall(__NR_connect, r[1], 0x20ef4000ul, 0x10ul);
    break;
  case 8:
    *(uint32_t*)0x2076c000 = (uint32_t)0xf;
    *(uint32_t*)0x2076c004 = (uint32_t)0x4;
    *(uint32_t*)0x2076c008 = (uint32_t)0x4;
    *(uint32_t*)0x2076c00c = (uint32_t)0x81;
    *(uint32_t*)0x2076c010 = (uint32_t)0x0;
    *(uint32_t*)0x2076c014 = (uint32_t)0x0;
    *(uint32_t*)0x2076c018 = (uint32_t)0x0;
    r[60] = syscall(__NR_bpf, 0x0ul, 0x2076c000ul, 0x14ul);
    break;
  case 9:
    *(uint32_t*)0x204eefe0 = r[60];
    *(uint64_t*)0x204eefe8 = (uint64_t)0x20fe6000;
    *(uint64_t*)0x204eeff0 = (uint64_t)0x20eb0fff;
    *(uint64_t*)0x204eeff8 = (uint64_t)0x0;
    memcpy((void*)0x20eb0fff, "\x05", 1);
    r[66] = syscall(__NR_bpf, 0x2ul, 0x204eefe0ul, 0x20ul);
    break;
  }
  return 0;
}

void test()
{
  long i;
  pthread_t th[20];

  memset(r, -1, sizeof(r));
  for (i = 0; i < 10; i++) {
    pthread_create(&th[i], 0, thr, (void*)i);
    usleep(rand() % 10000);
  }
  usleep(rand() % 100000);
}

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