// https://syzkaller.appspot.com/bug?id=ed27fa17fde97218578a0f64a9cc69ccadfc8fb8
// autogenerated by syzkaller (http://github.com/google/syzkaller)

#define _GNU_SOURCE

#include <arpa/inet.h>
#include <errno.h>
#include <errno.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 <sched.h>
#include <signal.h>
#include <signal.h>
#include <stdarg.h>
#include <stdarg.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdio.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <sys/prctl.h>
#include <sys/prctl.h>
#include <sys/resource.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/time.h>
#include <sys/time.h>
#include <sys/uio.h>
#include <sys/wait.h>
#include <sys/wait.h>
#include <time.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 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 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 int read_tun(char* data, int size)
{
  if (tunfd < 0)
    return -1;

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

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

static void loop();

static void sandbox_common()
{
  prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
  setpgrp();
  setsid();

  struct rlimit rlim;
  rlim.rlim_cur = rlim.rlim_max = 128 << 20;
  setrlimit(RLIMIT_AS, &rlim);
  rlim.rlim_cur = rlim.rlim_max = 8 << 20;
  setrlimit(RLIMIT_MEMLOCK, &rlim);
  rlim.rlim_cur = rlim.rlim_max = 1 << 20;
  setrlimit(RLIMIT_FSIZE, &rlim);
  rlim.rlim_cur = rlim.rlim_max = 1 << 20;
  setrlimit(RLIMIT_STACK, &rlim);
  rlim.rlim_cur = rlim.rlim_max = 0;
  setrlimit(RLIMIT_CORE, &rlim);

  unshare(CLONE_NEWNS);
  unshare(CLONE_NEWIPC);
  unshare(CLONE_IO);
}

static int do_sandbox_none(int executor_pid, bool enable_tun)
{
  int pid = fork();
  if (pid)
    return pid;

  sandbox_common();
  setup_tun(executor_pid, enable_tun);

  loop();
  doexit(1);
}

static void test();

void loop()
{
  int iter;
  for (iter = 0;; iter++) {
    int pid = fork();
    if (pid < 0)
      fail("clone failed");
    if (pid == 0) {
      prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
      setpgrp();
      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;
      }
    }
  }
}

long r[88];
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, 0x26ul, 0x5ul, 0x0ul);
    break;
  case 2:
    NONFAILING(*(uint16_t*)0x20ff9000 = (uint16_t)0x26);
    NONFAILING(memcpy(
        (void*)0x20ff9002,
        "\x61\x65\x61\x64\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
        14));
    NONFAILING(*(uint32_t*)0x20ff9010 = (uint32_t)0x0);
    NONFAILING(*(uint32_t*)0x20ff9014 = (uint32_t)0x0);
    NONFAILING(memcpy((void*)0x20ff9018,
                      "\x67\x63\x6d\x28\x74\x77\x6f\x66\x69\x73\x68\x2d"
                      "\x67\x65\x6e\x65\x72\x69\x63\x29\x00\x00\x00\x00"
                      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
                      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
                      "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
                      "\x00\x00\x00\x00",
                      64));
    r[7] = syscall(__NR_bind, r[1], 0x20ff9000ul, 0x58ul);
    break;
  case 3:
    r[8] = syscall(__NR_accept, r[1], 0x0ul, 0x0ul);
    break;
  case 4:
    NONFAILING(*(uint64_t*)0x201dcfc8 = (uint64_t)0x0);
    NONFAILING(*(uint32_t*)0x201dcfd0 = (uint32_t)0x0);
    NONFAILING(*(uint64_t*)0x201dcfd8 = (uint64_t)0x20012000);
    NONFAILING(*(uint64_t*)0x201dcfe0 = (uint64_t)0x1);
    NONFAILING(*(uint64_t*)0x201dcfe8 = (uint64_t)0x20719fb8);
    NONFAILING(*(uint64_t*)0x201dcff0 = (uint64_t)0x48);
    NONFAILING(*(uint32_t*)0x201dcff8 = (uint32_t)0xd0);
    NONFAILING(*(uint64_t*)0x20012000 = (uint64_t)0x20049000);
    NONFAILING(*(uint64_t*)0x20012008 = (uint64_t)0x0);
    NONFAILING(*(uint64_t*)0x20719fb8 = (uint64_t)0x18);
    NONFAILING(*(uint32_t*)0x20719fc0 = (uint32_t)0x117);
    NONFAILING(*(uint32_t*)0x20719fc4 = (uint32_t)0x3);
    NONFAILING(*(uint32_t*)0x20719fc8 = (uint32_t)0x1);
    NONFAILING(*(uint64_t*)0x20719fd0 = (uint64_t)0x18);
    NONFAILING(*(uint32_t*)0x20719fd8 = (uint32_t)0x117);
    NONFAILING(*(uint32_t*)0x20719fdc = (uint32_t)0x3);
    NONFAILING(*(uint32_t*)0x20719fe0 = (uint32_t)0x0);
    NONFAILING(*(uint64_t*)0x20719fe8 = (uint64_t)0x18);
    NONFAILING(*(uint32_t*)0x20719ff0 = (uint32_t)0x117);
    NONFAILING(*(uint32_t*)0x20719ff4 = (uint32_t)0x3);
    NONFAILING(*(uint32_t*)0x20719ff8 = (uint32_t)0x1);
    r[30] = syscall(__NR_sendmsg, r[8], 0x201dcfc8ul, 0x8010ul);
    break;
  case 5:
    NONFAILING(memcpy((void*)0x2023aff0, "\xe5\xfc\x00\x08\x91\xaa\x78"
                                         "\x5d\xeb\xcd\xfe\xf1\xdd\xb4"
                                         "\x21\x13",
                      16));
    r[32] = syscall(__NR_setsockopt, r[1], 0x117ul, 0x1ul, 0x2023aff0ul,
                    0x10ul);
    break;
  case 6:
    NONFAILING(*(uint64_t*)0x20709fc8 = (uint64_t)0x20dab000);
    NONFAILING(*(uint32_t*)0x20709fd0 = (uint32_t)0x1c);
    NONFAILING(*(uint64_t*)0x20709fd8 = (uint64_t)0x2031efd0);
    NONFAILING(*(uint64_t*)0x20709fe0 = (uint64_t)0x3);
    NONFAILING(*(uint64_t*)0x20709fe8 = (uint64_t)0x20d40fbc);
    NONFAILING(*(uint64_t*)0x20709ff0 = (uint64_t)0x0);
    NONFAILING(*(uint32_t*)0x20709ff8 = (uint32_t)0x5);
    NONFAILING(*(uint64_t*)0x2031efd0 = (uint64_t)0x2098e000);
    NONFAILING(*(uint64_t*)0x2031efd8 = (uint64_t)0x0);
    NONFAILING(*(uint64_t*)0x2031efe0 = (uint64_t)0x2010f000);
    NONFAILING(*(uint64_t*)0x2031efe8 = (uint64_t)0x1000);
    NONFAILING(*(uint64_t*)0x2031eff0 = (uint64_t)0x20e95fd4);
    NONFAILING(*(uint64_t*)0x2031eff8 = (uint64_t)0x0);
    r[46] = syscall(__NR_recvmsg, r[8], 0x20709fc8ul, 0x2103ul);
    break;
  case 7:
    NONFAILING(*(uint64_t*)0x204bb000 = (uint64_t)0x0);
    NONFAILING(*(uint32_t*)0x204bb008 = (uint32_t)0x0);
    NONFAILING(*(uint64_t*)0x204bb010 = (uint64_t)0x2016afe0);
    NONFAILING(*(uint64_t*)0x204bb018 = (uint64_t)0x2);
    NONFAILING(*(uint64_t*)0x204bb020 = (uint64_t)0x204d7000);
    NONFAILING(*(uint64_t*)0x204bb028 = (uint64_t)0xa8);
    NONFAILING(*(uint32_t*)0x204bb030 = (uint32_t)0x8000);
    NONFAILING(*(uint64_t*)0x2016afe0 = (uint64_t)0x20b70f86);
    NONFAILING(*(uint64_t*)0x2016afe8 = (uint64_t)0x0);
    NONFAILING(*(uint64_t*)0x2016aff0 = (uint64_t)0x20c13000);
    NONFAILING(*(uint64_t*)0x2016aff8 = (uint64_t)0xfc);
    NONFAILING(memcpy(
        (void*)0x20c13000,
        "\x7a\x70\xcd\x59\x8e\x27\x71\x8f\x86\x55\xc6\x88\x5f\xde\x5e"
        "\x54\x6d\xcf\xa6\x50\x39\xa0\x4f\xed\x2c\xf1\x30\xa1\x78\xbb"
        "\x2d\xa1\xa4\x31\xe0\x43\xdc\x21\x73\x1a\xf1\x55\x49\x0e\x51"
        "\x1e\x17\x92\x40\xb7\xe1\x7c\xe1\xf5\x9b\xca\x95\xe4\x1d\x52"
        "\x2d\x97\xe7\x22\xb7\xd2\xa7\x6f\x21\x69\xde\xda\x55\xaa\xa8"
        "\xa8\x21\xa3\x00\x00\x4d\x85\x0a\xbe\x89\x02\x08\xe4\xc5\xfd"
        "\xd2\xc8\xde\x68\x65\xaa\x6e\x57\x8c\x2e\x97\x9b\x78\xf9\xcc"
        "\xf6\x55\x72\x01\x08\x46\x41\x75\x47\x8e\x64\x99\x16\x47\x9a"
        "\xff\x0d\x86\x20\x75\x75\x10\x5b\xdd\xb0\x50\xa6\x09\x28\xab"
        "\x0b\xe0\x40\xf1\xd6\xa4\x14\x00\x54\xe7\xa4\x1d\x93\x3e\x13"
        "\xf2\xec\x64\xb4\x86\x04\xfb\x8d\x6f\x46\xa5\x13\x82\x5c\x24"
        "\x3f\x4e\xc1\x29\xbc\xd9\x42\x56\xce\x81\xda\xf8\x5c\x4c\x61"
        "\x49\xc2\x09\x3a\x02\xab\x0e\xf1\xaf\x20\xb7\xd9\xbf\x87\xec"
        "\x4a\xe3\x59\x5d\x17\x2c\x16\x44\x2e\xa2\x4f\x2b\xc7\x2e\xe2"
        "\x19\x6a\xaa\x35\xc6\x5b\x91\x6e\x78\x0c\xf3\xa3\x43\x27\x45"
        "\xb8\x61\x86\xc5\x30\x2a\xb0\x5e\x43\x10\xb3\x75\x9a\x64\x40"
        "\x0d\xf4\x31\x61\x92\x6c\xf4\xba\xf6\xbb\x6d\x54",
        252));
    NONFAILING(*(uint64_t*)0x204d7000 = (uint64_t)0x18);
    NONFAILING(*(uint32_t*)0x204d7008 = (uint32_t)0x117);
    NONFAILING(*(uint32_t*)0x204d700c = (uint32_t)0x3);
    NONFAILING(*(uint32_t*)0x204d7010 = (uint32_t)0x1);
    NONFAILING(*(uint64_t*)0x204d7018 = (uint64_t)0x18);
    NONFAILING(*(uint32_t*)0x204d7020 = (uint32_t)0x117);
    NONFAILING(*(uint32_t*)0x204d7024 = (uint32_t)0x4);
    NONFAILING(*(uint32_t*)0x204d7028 = (uint32_t)0x3);
    NONFAILING(*(uint64_t*)0x204d7030 = (uint64_t)0x18);
    NONFAILING(*(uint32_t*)0x204d7038 = (uint32_t)0x117);
    NONFAILING(*(uint32_t*)0x204d703c = (uint32_t)0x3);
    NONFAILING(*(uint32_t*)0x204d7040 = (uint32_t)0x0);
    NONFAILING(*(uint64_t*)0x204d7048 = (uint64_t)0x18);
    NONFAILING(*(uint32_t*)0x204d7050 = (uint32_t)0x117);
    NONFAILING(*(uint32_t*)0x204d7054 = (uint32_t)0x4);
    NONFAILING(*(uint32_t*)0x204d7058 = (uint32_t)0xfffffffffffffeff);
    NONFAILING(*(uint64_t*)0x204d7060 = (uint64_t)0x18);
    NONFAILING(*(uint32_t*)0x204d7068 = (uint32_t)0x117);
    NONFAILING(*(uint32_t*)0x204d706c = (uint32_t)0x4);
    NONFAILING(*(uint32_t*)0x204d7070 = (uint32_t)0x0);
    NONFAILING(*(uint64_t*)0x204d7078 = (uint64_t)0x18);
    NONFAILING(*(uint32_t*)0x204d7080 = (uint32_t)0x117);
    NONFAILING(*(uint32_t*)0x204d7084 = (uint32_t)0x4);
    NONFAILING(*(uint32_t*)0x204d7088 = (uint32_t)0x3ff);
    NONFAILING(*(uint64_t*)0x204d7090 = (uint64_t)0x18);
    NONFAILING(*(uint32_t*)0x204d7098 = (uint32_t)0x117);
    NONFAILING(*(uint32_t*)0x204d709c = (uint32_t)0x3);
    NONFAILING(*(uint32_t*)0x204d70a0 = (uint32_t)0x1);
    r[87] = syscall(__NR_sendmmsg, r[8], 0x204bb000ul, 0x1ul, 0xc080ul);
    break;
  }
  return 0;
}

void test()
{
  long i;
  pthread_t th[16];

  memset(r, -1, sizeof(r));
  for (i = 0; i < 8; i++) {
    pthread_create(&th[i], 0, thr, (void*)i);
    usleep(rand() % 10000);
  }
  usleep(rand() % 100000);
}

int main()
{
  int i;
  for (i = 0; i < 8; i++) {
    if (fork() == 0) {
      install_segv_handler();
      int pid = do_sandbox_none(i, true);
      int status = 0;
      while (waitpid(pid, &status, __WALL) != pid) {
      }
      return 0;
    }
  }
  sleep(1000000);
  return 0;
}