// https://syzkaller.appspot.com/bug?id=dda626cdbd87eafe9a755acbbe102e2b6096b256
// autogenerated by syzkaller (https://github.com/google/syzkaller)

#define _GNU_SOURCE

#include <arpa/inet.h>
#include <endian.h>
#include <errno.h>
#include <fcntl.h>
#include <net/if_arp.h>
#include <sched.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/resource.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <sys/wait.h>
#include <unistd.h>

#include <linux/if.h>
#include <linux/if_ether.h>
#include <linux/if_tun.h>
#include <linux/ip.h>
#include <linux/tcp.h>

#define BITMASK(bf_off, bf_len) (((1ull << (bf_len)) - 1) << (bf_off))
#define STORE_BY_BITMASK(type, htobe, addr, val, bf_off, bf_len)               \
  *(type*)(addr) =                                                             \
      htobe((htobe(*(type*)(addr)) & ~BITMASK((bf_off), (bf_len))) |           \
            (((type)(val) << (bf_off)) & BITMASK((bf_off), (bf_len))))

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 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)
    exit(1);
  if ((size_t)rv >= size)
    exit(1);
}

#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(bool panic, 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);
  va_end(args);
  rv = system(command);
  if (rv) {
    if (panic)
      exit(1);
  }
}

static int tunfd = -1;
static int tun_frags_enabled;
#define SYZ_TUN_MAX_PACKET_SIZE 1000

#define TUN_IFACE "syz_tun"

#define LOCAL_MAC "aa:aa:aa:aa:aa:aa"
#define REMOTE_MAC "aa:aa:aa:aa:aa:bb"

#define LOCAL_IPV4 "172.20.20.170"
#define REMOTE_IPV4 "172.20.20.187"

#define LOCAL_IPV6 "fe80::aa"
#define REMOTE_IPV6 "fe80::bb"

#define IFF_NAPI 0x0010
#define IFF_NAPI_FRAGS 0x0020

static void initialize_tun(void)
{
  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;
  }
  const int kTunFd = 240;
  if (dup2(tunfd, kTunFd) < 0)
    exit(1);
  close(tunfd);
  tunfd = kTunFd;
  struct ifreq ifr;
  memset(&ifr, 0, sizeof(ifr));
  strncpy(ifr.ifr_name, TUN_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)
      exit(1);
  }
  if (ioctl(tunfd, TUNGETIFF, (void*)&ifr) < 0)
    exit(1);
  tun_frags_enabled = (ifr.ifr_flags & IFF_NAPI_FRAGS) != 0;
  execute_command(0, "sysctl -w net.ipv6.conf.%s.accept_dad=0", TUN_IFACE);
  execute_command(0, "sysctl -w net.ipv6.conf.%s.router_solicitations=0",
                  TUN_IFACE);
  execute_command(1, "ip link set dev %s address %s", TUN_IFACE, LOCAL_MAC);
  execute_command(1, "ip addr add %s/24 dev %s", LOCAL_IPV4, TUN_IFACE);
  execute_command(1, "ip neigh add %s lladdr %s dev %s nud permanent",
                  REMOTE_IPV4, REMOTE_MAC, TUN_IFACE);
  execute_command(0, "ip -6 addr add %s/120 dev %s", LOCAL_IPV6, TUN_IFACE);
  execute_command(0, "ip -6 neigh add %s lladdr %s dev %s nud permanent",
                  REMOTE_IPV6, REMOTE_MAC, TUN_IFACE);
  execute_command(1, "ip link set dev %s up", TUN_IFACE);
}

#define DEV_IPV4 "172.20.20.%d"
#define DEV_IPV6 "fe80::%02hx"
#define DEV_MAC "aa:aa:aa:aa:aa:%02hx"

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);
}
static void initialize_netdevices(void)
{
  unsigned i;
  const char* devtypes[] = {"ip6gretap", "bridge", "vcan", "bond", "team"};
  const char* devnames[] = {"lo",
                            "sit0",
                            "bridge0",
                            "vcan0",
                            "tunl0",
                            "gre0",
                            "gretap0",
                            "ip_vti0",
                            "ip6_vti0",
                            "ip6tnl0",
                            "ip6gre0",
                            "ip6gretap0",
                            "erspan0",
                            "bond0",
                            "veth0",
                            "veth1",
                            "team0",
                            "veth0_to_bridge",
                            "veth1_to_bridge",
                            "veth0_to_bond",
                            "veth1_to_bond",
                            "veth0_to_team",
                            "veth1_to_team"};
  const char* devmasters[] = {"bridge", "bond", "team"};
  for (i = 0; i < sizeof(devtypes) / (sizeof(devtypes[0])); i++)
    execute_command(0, "ip link add dev %s0 type %s", devtypes[i], devtypes[i]);
  execute_command(0, "ip link add type veth");
  for (i = 0; i < sizeof(devmasters) / (sizeof(devmasters[0])); i++) {
    execute_command(
        0, "ip link add name %s_slave_0 type veth peer name veth0_to_%s",
        devmasters[i], devmasters[i]);
    execute_command(
        0, "ip link add name %s_slave_1 type veth peer name veth1_to_%s",
        devmasters[i], devmasters[i]);
    execute_command(0, "ip link set %s_slave_0 master %s0", devmasters[i],
                    devmasters[i]);
    execute_command(0, "ip link set %s_slave_1 master %s0", devmasters[i],
                    devmasters[i]);
    execute_command(0, "ip link set veth0_to_%s up", devmasters[i]);
    execute_command(0, "ip link set veth1_to_%s up", devmasters[i]);
  }
  execute_command(0, "ip link set bridge_slave_0 up");
  execute_command(0, "ip link set bridge_slave_1 up");
  for (i = 0; i < sizeof(devnames) / (sizeof(devnames[0])); i++) {
    char addr[32];
    snprintf_check(addr, sizeof(addr), DEV_IPV4, i + 10);
    execute_command(0, "ip -4 addr add %s/24 dev %s", addr, devnames[i]);
    snprintf_check(addr, sizeof(addr), DEV_IPV6, i + 10);
    execute_command(0, "ip -6 addr add %s/120 dev %s", addr, devnames[i]);
    snprintf_check(addr, sizeof(addr), DEV_MAC, i + 10);
    execute_command(0, "ip link set dev %s address %s", devnames[i], addr);
    execute_command(0, "ip link set dev %s up", devnames[i]);
  }
}

#define MAX_FRAGS 4
struct vnet_fragmentation {
  uint32_t full;
  uint32_t count;
  uint32_t frags[MAX_FRAGS];
};

static long syz_emit_ethernet(long a0, long a1, long a2)
{
  if (tunfd < 0)
    return (uintptr_t)-1;
  uint32_t length = a0;
  char* data = (char*)a1;
  struct vnet_fragmentation* frags = (struct vnet_fragmentation*)a2;
  struct iovec vecs[MAX_FRAGS + 1];
  uint32_t nfrags = 0;
  if (!tun_frags_enabled || frags == NULL) {
    vecs[nfrags].iov_base = data;
    vecs[nfrags].iov_len = length;
    nfrags++;
  } else {
    bool full = true;
    uint32_t i, count = 0;
    full = frags->full;
    count = frags->count;
    if (count > MAX_FRAGS)
      count = MAX_FRAGS;
    for (i = 0; i < count && length != 0; i++) {
      uint32_t size = 0;
      size = frags->frags[i];
      if (size > length)
        size = length;
      vecs[nfrags].iov_base = data;
      vecs[nfrags].iov_len = size;
      nfrags++;
      data += size;
      length -= size;
    }
    if (length != 0 && (full || nfrags == 0)) {
      vecs[nfrags].iov_base = data;
      vecs[nfrags].iov_len = length;
      nfrags++;
    }
  }
  return writev(tunfd, vecs, nfrags);
}

static void setup_common()
{
  if (mount(0, "/sys/fs/fuse/connections", "fusectl", 0, 0)) {
  }
}

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 = 200 << 20;
  setrlimit(RLIMIT_AS, &rlim);
  rlim.rlim_cur = rlim.rlim_max = 32 << 20;
  setrlimit(RLIMIT_MEMLOCK, &rlim);
  rlim.rlim_cur = rlim.rlim_max = 136 << 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);
  rlim.rlim_cur = rlim.rlim_max = 256;
  setrlimit(RLIMIT_NOFILE, &rlim);
  if (unshare(CLONE_NEWNS)) {
  }
  if (unshare(CLONE_NEWIPC)) {
  }
  if (unshare(0x02000000)) {
  }
  if (unshare(CLONE_NEWUTS)) {
  }
  if (unshare(CLONE_SYSVSEM)) {
  }
}

int wait_for_loop(int pid)
{
  if (pid < 0)
    exit(1);
  int status = 0;
  while (waitpid(-1, &status, __WALL) != pid) {
  }
  return WEXITSTATUS(status);
}

static int do_sandbox_none(void)
{
  if (unshare(CLONE_NEWPID)) {
  }
  int pid = fork();
  if (pid != 0)
    return wait_for_loop(pid);
  setup_common();
  sandbox_common();
  if (unshare(CLONE_NEWNET)) {
  }
  initialize_tun();
  initialize_netdevices();
  loop();
  exit(1);
}

void loop(void)
{
  *(uint8_t*)0x200000c0 = 0xaa;
  *(uint8_t*)0x200000c1 = 0xaa;
  *(uint8_t*)0x200000c2 = 0xaa;
  *(uint8_t*)0x200000c3 = 0xaa;
  *(uint8_t*)0x200000c4 = 0xaa;
  *(uint8_t*)0x200000c5 = 0xaa;
  *(uint8_t*)0x200000c6 = -1;
  *(uint8_t*)0x200000c7 = -1;
  *(uint8_t*)0x200000c8 = -1;
  *(uint8_t*)0x200000c9 = -1;
  *(uint8_t*)0x200000ca = -1;
  *(uint8_t*)0x200000cb = -1;
  *(uint16_t*)0x200000cc = htobe16(0x800);
  STORE_BY_BITMASK(uint8_t, , 0x200000ce, 5, 0, 4);
  STORE_BY_BITMASK(uint8_t, , 0x200000ce, 4, 4, 4);
  STORE_BY_BITMASK(uint8_t, , 0x200000cf, 0, 0, 2);
  STORE_BY_BITMASK(uint8_t, , 0x200000cf, 0, 2, 6);
  *(uint16_t*)0x200000d0 = htobe16(0x5c);
  *(uint16_t*)0x200000d2 = htobe16(0);
  *(uint16_t*)0x200000d4 = htobe16(0);
  *(uint8_t*)0x200000d6 = 0;
  *(uint8_t*)0x200000d7 = 1;
  *(uint16_t*)0x200000d8 = htobe16(0);
  *(uint8_t*)0x200000da = 0xac;
  *(uint8_t*)0x200000db = 0x23;
  *(uint8_t*)0x200000dc = 0x14;
  *(uint8_t*)0x200000dd = 0xbb;
  *(uint8_t*)0x200000de = 0xac;
  *(uint8_t*)0x200000df = 0x14;
  *(uint8_t*)0x200000e0 = 0x14;
  *(uint8_t*)0x200000e1 = 0x11;
  *(uint8_t*)0x200000e2 = 5;
  *(uint8_t*)0x200000e3 = 4;
  *(uint16_t*)0x200000e4 = htobe16(0);
  *(uint8_t*)0x200000e6 = 0;
  *(uint8_t*)0x200000e7 = 0;
  *(uint16_t*)0x200000e8 = 0;
  STORE_BY_BITMASK(uint8_t, , 0x200000ea, 0x10, 0, 4);
  STORE_BY_BITMASK(uint8_t, , 0x200000ea, 4, 4, 4);
  STORE_BY_BITMASK(uint8_t, , 0x200000eb, 0, 0, 2);
  STORE_BY_BITMASK(uint8_t, , 0x200000eb, 0, 2, 6);
  *(uint16_t*)0x200000ec = htobe16(0);
  *(uint16_t*)0x200000ee = htobe16(0);
  *(uint16_t*)0x200000f0 = htobe16(0);
  *(uint8_t*)0x200000f2 = 0;
  *(uint8_t*)0x200000f3 = 0x11;
  *(uint16_t*)0x200000f4 = htobe16(0);
  *(uint8_t*)0x200000f6 = 0xac;
  *(uint8_t*)0x200000f7 = 0x23;
  *(uint8_t*)0x200000f8 = 0x14;
  *(uint8_t*)0x200000f9 = 0xaa;
  *(uint8_t*)0x200000fa = 0xac;
  *(uint8_t*)0x200000fb = 0x14;
  *(uint8_t*)0x200000fc = 0x14;
  *(uint8_t*)0x200000fd = 0;
  *(uint8_t*)0x200000fe = 8;
  *(uint8_t*)0x200000ff = 0x2c;
  *(uint8_t*)0x20000100 = 0;
  STORE_BY_BITMASK(uint8_t, , 0x20000101, 0, 0, 4);
  STORE_BY_BITMASK(uint8_t, , 0x20000101, 0, 4, 4);
  *(uint32_t*)0x20000102 = htobe32(0);
  *(uint32_t*)0x20000106 = htobe32(0);
  *(uint32_t*)0x2000010a = htobe32(0xe0000002);
  *(uint32_t*)0x2000010e = htobe32(0);
  *(uint32_t*)0x20000112 = htobe32(0xe0000001);
  *(uint32_t*)0x20000116 = htobe32(0);
  *(uint32_t*)0x2000011a = htobe32(0);
  *(uint32_t*)0x2000011e = htobe32(0x7f000001);
  *(uint32_t*)0x20000122 = htobe32(0);
  *(uint32_t*)0x20000126 = htobe32(0);
  struct csum_inet csum_1;
  csum_inet_init(&csum_1);
  csum_inet_update(&csum_1, (const uint8_t*)0x200000e2, 72);
  *(uint16_t*)0x200000e4 = csum_inet_digest(&csum_1);
  struct csum_inet csum_2;
  csum_inet_init(&csum_2);
  csum_inet_update(&csum_2, (const uint8_t*)0x200000ce, 20);
  *(uint16_t*)0x200000d8 = csum_inet_digest(&csum_2);
  syz_emit_ethernet(0x6a, 0x200000c0, 0);
  syscall(__NR_setsockopt, -1, 0x117, 5, 0, 0);
  syscall(__NR_accept, -1, 0, 0);
}
int main(void)
{
  syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0);
  do_sandbox_none();
  return 0;
}