// https://syzkaller.appspot.com/bug?id=6dcd14a729df98f989c7b76d254226ae67084efd
// autogenerated by syzkaller (http://github.com/google/syzkaller)

#define _GNU_SOURCE
#include <arpa/inet.h>
#include <endian.h>
#include <errno.h>
#include <fcntl.h>
#include <fcntl.h>
#include <linux/futex.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 <string.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);
}

#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);
}

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_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);
  }
}

static void test();

void loop()
{
  while (1) {
    test();
  }
}

struct thread_t {
  int created, running, call;
  pthread_t th;
};

static struct thread_t threads[16];
static void execute_call(int call);
static int running;

static void* thr(void* arg)
{
  struct thread_t* th = (struct thread_t*)arg;
  for (;;) {
    while (!__atomic_load_n(&th->running, __ATOMIC_ACQUIRE))
      syscall(SYS_futex, &th->running, FUTEX_WAIT, 0, 0);
    execute_call(th->call);
    __atomic_fetch_sub(&running, 1, __ATOMIC_RELAXED);
    __atomic_store_n(&th->running, 0, __ATOMIC_RELEASE);
    syscall(SYS_futex, &th->running, FUTEX_WAKE);
  }
  return 0;
}

static void execute(int num_calls)
{
  int call, thread;
  running = 0;
  for (call = 0; call < num_calls; call++) {
    for (thread = 0; thread < sizeof(threads) / sizeof(threads[0]); thread++) {
      struct thread_t* th = &threads[thread];
      if (!th->created) {
        th->created = 1;
        pthread_attr_t attr;
        pthread_attr_init(&attr);
        pthread_attr_setstacksize(&attr, 128 << 10);
        pthread_create(&th->th, &attr, thr, th);
      }
      if (!__atomic_load_n(&th->running, __ATOMIC_ACQUIRE)) {
        th->call = call;
        __atomic_fetch_add(&running, 1, __ATOMIC_RELAXED);
        __atomic_store_n(&th->running, 1, __ATOMIC_RELEASE);
        syscall(SYS_futex, &th->running, FUTEX_WAKE);
        struct timespec ts;
        ts.tv_sec = 0;
        ts.tv_nsec = 20 * 1000 * 1000;
        syscall(SYS_futex, &th->running, FUTEX_WAIT, 1, &ts);
        if (running)
          usleep((call == num_calls - 1) ? 10000 : 1000);
        break;
      }
    }
  }
}

#ifndef __NR_write
#define __NR_write 4
#endif
#ifndef __NR_read
#define __NR_read 3
#endif
#ifndef __NR_mmap
#define __NR_mmap 192
#endif
#undef __NR_mmap
#define __NR_mmap __NR_mmap2

long r[1];
uint64_t procid;
void execute_call(int call)
{
  switch (call) {
  case 0:
    syscall(__NR_mmap, 0x20000000, 0xfff000, 3, 0x32, -1, 0);
    break;
  case 1:
    NONFAILING(memcpy((void*)0x2002a000, "/dev/sg#", 9));
    r[0] = syz_open_dev(0x2002a000, 0, 0x142);
    break;
  case 2:
    NONFAILING(*(uint8_t*)0x20254000 = 0);
    NONFAILING(*(uint8_t*)0x20254001 = 0);
    NONFAILING(*(uint16_t*)0x20254002 = 0);
    NONFAILING(*(uint16_t*)0x20254004 = 0);
    NONFAILING(*(uint16_t*)0x20254006 = 5);
    NONFAILING(*(uint16_t*)0x20254008 = 0);
    NONFAILING(STORE_BY_BITMASK(uint8_t, 0x2025400a, 0, 0, 4));
    NONFAILING(STORE_BY_BITMASK(uint8_t, 0x2025400a, 6, 4, 4));
    NONFAILING(memcpy((void*)0x2025400b, "\xde\x57\x29", 3));
    NONFAILING(*(uint16_t*)0x2025400e = htobe16(0x68));
    NONFAILING(*(uint8_t*)0x20254010 = 0x7f);
    NONFAILING(*(uint8_t*)0x20254011 = 9);
    NONFAILING(*(uint8_t*)0x20254012 = 0xfe);
    NONFAILING(*(uint8_t*)0x20254013 = 0x80);
    NONFAILING(*(uint8_t*)0x20254014 = 0);
    NONFAILING(*(uint8_t*)0x20254015 = 0);
    NONFAILING(*(uint8_t*)0x20254016 = 0);
    NONFAILING(*(uint8_t*)0x20254017 = 0);
    NONFAILING(*(uint8_t*)0x20254018 = 0);
    NONFAILING(*(uint8_t*)0x20254019 = 0);
    NONFAILING(*(uint8_t*)0x2025401a = 0);
    NONFAILING(*(uint8_t*)0x2025401b = 0);
    NONFAILING(*(uint8_t*)0x2025401c = 0);
    NONFAILING(*(uint8_t*)0x2025401d = 0);
    NONFAILING(*(uint8_t*)0x2025401e = 0);
    NONFAILING(*(uint8_t*)0x2025401f = 0);
    NONFAILING(*(uint8_t*)0x20254020 = 0 + procid * 1);
    NONFAILING(*(uint8_t*)0x20254021 = 0xaa);
    NONFAILING(*(uint8_t*)0x20254022 = 0xfe);
    NONFAILING(*(uint8_t*)0x20254023 = 0x80);
    NONFAILING(*(uint8_t*)0x20254024 = 0);
    NONFAILING(*(uint8_t*)0x20254025 = 0);
    NONFAILING(*(uint8_t*)0x20254026 = 0);
    NONFAILING(*(uint8_t*)0x20254027 = 0);
    NONFAILING(*(uint8_t*)0x20254028 = 0);
    NONFAILING(*(uint8_t*)0x20254029 = 0);
    NONFAILING(*(uint8_t*)0x2025402a = 0);
    NONFAILING(*(uint8_t*)0x2025402b = 0);
    NONFAILING(*(uint8_t*)0x2025402c = 0);
    NONFAILING(*(uint8_t*)0x2025402d = 0);
    NONFAILING(*(uint8_t*)0x2025402e = 0);
    NONFAILING(*(uint8_t*)0x2025402f = 0);
    NONFAILING(*(uint8_t*)0x20254030 = 0 + procid * 1);
    NONFAILING(*(uint8_t*)0x20254031 = 0xaa);
    NONFAILING(*(uint8_t*)0x20254032 = 0);
    NONFAILING(*(uint8_t*)0x20254033 = 0);
    NONFAILING(*(uint8_t*)0x20254034 = 0);
    NONFAILING(*(uint8_t*)0x20254035 = 0);
    NONFAILING(*(uint32_t*)0x20254036 = 7);
    NONFAILING(*(uint16_t*)0x2025403a = htobe16(0x4e20 + procid * 4));
    NONFAILING(*(uint16_t*)0x2025403c = htobe16(0x4e20 + procid * 4));
    NONFAILING(*(uint32_t*)0x2025403e = 0x42424242);
    NONFAILING(*(uint32_t*)0x20254042 = 0x42424242);
    NONFAILING(STORE_BY_BITMASK(uint8_t, 0x20254046, 0, 0, 1));
    NONFAILING(STORE_BY_BITMASK(uint8_t, 0x20254046, 0, 1, 3));
    NONFAILING(STORE_BY_BITMASK(uint8_t, 0x20254046, 0x18, 4, 4));
    NONFAILING(*(uint8_t*)0x20254047 = 0x2c);
    NONFAILING(*(uint16_t*)0x20254048 = htobe16(0));
    NONFAILING(*(uint16_t*)0x2025404a = 0);
    NONFAILING(*(uint16_t*)0x2025404c = htobe16(0));
    NONFAILING(*(uint8_t*)0x2025404e = 8);
    NONFAILING(*(uint8_t*)0x2025404f = 0xa);
    NONFAILING(*(uint32_t*)0x20254050 = htobe32(3));
    NONFAILING(*(uint32_t*)0x20254054 = htobe32(0xc850));
    NONFAILING(*(uint8_t*)0x20254058 = 5);
    NONFAILING(*(uint8_t*)0x20254059 = 0x26);
    NONFAILING(*(uint32_t*)0x2025405a = htobe32(0x800));
    NONFAILING(*(uint32_t*)0x2025405e = htobe32(0));
    NONFAILING(*(uint32_t*)0x20254062 = htobe32(0));
    NONFAILING(*(uint32_t*)0x20254066 = htobe32(0));
    NONFAILING(*(uint32_t*)0x2025406a = htobe32(0x3d));
    NONFAILING(*(uint32_t*)0x2025406e = htobe32(0));
    NONFAILING(*(uint32_t*)0x20254072 = htobe32(0x10001));
    NONFAILING(*(uint32_t*)0x20254076 = htobe32(0));
    NONFAILING(*(uint32_t*)0x2025407a = htobe32(0));
    NONFAILING(*(uint8_t*)0x2025407e = 2);
    NONFAILING(*(uint8_t*)0x2025407f = 4);
    NONFAILING(*(uint16_t*)0x20254080 = 0xac1);
    NONFAILING(*(uint8_t*)0x20254082 = 0);
    NONFAILING(*(uint8_t*)0x20254083 = 2);
    NONFAILING(*(uint8_t*)0x20254084 = 0);
    NONFAILING(*(uint8_t*)0x20254085 = 0x13);
    NONFAILING(*(uint8_t*)0x20254086 = 0x12);
    NONFAILING(memcpy(
        (void*)0x20254087,
        "\x40\x08\x07\xe3\xee\xe9\xb1\x73\xb4\x08\x11\x5e\xf4\x5c\x5e\x18",
        16));
    NONFAILING(*(uint8_t*)0x20254097 = 3);
    NONFAILING(*(uint8_t*)0x20254098 = 3);
    NONFAILING(*(uint8_t*)0x20254099 = 6);
    struct csum_inet csum_1;
    csum_inet_init(&csum_1);
    NONFAILING(csum_inet_update(&csum_1, (const uint8_t*)0x20254012, 16));
    NONFAILING(csum_inet_update(&csum_1, (const uint8_t*)0x20254022, 16));
    uint32_t csum_1_chunk_2 = 0x60000000;
    csum_inet_update(&csum_1, (const uint8_t*)&csum_1_chunk_2, 4);
    uint32_t csum_1_chunk_3 = 0x6000000;
    csum_inet_update(&csum_1, (const uint8_t*)&csum_1_chunk_3, 4);
    NONFAILING(csum_inet_update(&csum_1, (const uint8_t*)0x2025403a, 96));
    NONFAILING(*(uint16_t*)0x2025404a = csum_inet_digest(&csum_1));
    syscall(__NR_write, r[0], 0x20254000, 0x9a);
    break;
  case 3:
    syscall(__NR_read, r[0], 0x20cd9000, 0);
    break;
  }
}

void test()
{
  memset(r, -1, sizeof(r));
  execute(4);
}

int main()
{
  for (procid = 0; procid < 8; procid++) {
    if (fork() == 0) {
      install_segv_handler();
      for (;;) {
        setup_tun(procid, true);
        loop();
      }
    }
  }
  sleep(1000000);
  return 0;
}