// 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/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 <stdarg.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdio.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 <errno.h>
#include <stdarg.h>
#include <stdint.h>
#include <stdio.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 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(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);
  rv = system(command);
  if (panic && 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 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 = 252;
  if (dup2(tunfd, kTunFd) < 0)
    fail("dup2(tunfd, kTunFd) failed");
  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)
      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;

  execute_command(1, "sysctl -w net.ipv6.conf.%s.accept_dad=0", TUN_IFACE);

  execute_command(1, "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 -6 addr add %s/120 dev %s", LOCAL_IPV6, TUN_IFACE);
  execute_command(1, "ip neigh add %s lladdr %s dev %s nud permanent",
                  REMOTE_IPV4, REMOTE_MAC, TUN_IFACE);
  execute_command(1, "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 initialize_netdevices(void)
{
  unsigned i;
  const char* devtypes[] = {"ip6gretap", "bridge", "vcan", "bond", "veth"};
  const char* devnames[] = {"lo",       "sit0",    "bridge0", "vcan0",
                            "tunl0",    "gre0",    "gretap0", "ip_vti0",
                            "ip6_vti0", "ip6tnl0", "ip6gre0", "ip6gretap0",
                            "erspan0",  "bond0",   "veth0",   "veth1"};

  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 dev veth1 type veth");
  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]);
  }
}

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;
    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();
  }
}

uint64_t r[1] = {0xffffffffffffffff};
void test()
{
  long res;
  memcpy((void*)0x20005000, "/dev/sg#", 9);
  res = syz_open_dev(0x20005000, 0, 0x8002);
  if (res != -1)
    r[0] = res;
  memcpy((void*)0x20000440,
         "\xb6\x3d\xc0\x7f\x34\x33\x02\x00\xf6\x0c\x00\x00\x00\x72\x4a\xed\x8b"
         "\x27\x00\x3e\xf0\x6d\x7f\x7a\x26\x2f\x89\x4b\x4c\x3e\x37\xd5\x01\x1d"
         "\xcc\x60\x6a\xed\x5e\x95\xd2\xbc\x70\x18\xce\xbc\xdc\xd1\xb3\x18\x82"
         "\xe5\xcb\x00\x00\x01\x00\x00\x00\x00\x00\xfb\x1e\xef\x15\x87\x16\x00"
         "\x4f\x76\xac\xb2\xc3\x86\xe3\x24\x11\x49\xc3\x36\x48\xa6\xb1\x69\xd9"
         "\x79\xb6\xd5\x90\x06\x1b\xf7\xdb\x76\x70\xb4\xbe\xd1\x24\xde\x49\x08"
         "\xa8\xd6\xc5\x55\x74\x65\x72\x46\x44\x8a\x1b\x78\xde\xcc\x6d\x96\x39"
         "\x35\xdd\x7c\x57\x58\x39\xc7\x60\xa6\xf7\xf0\xbe\xcb\x0e\xe8\x79\xa6"
         "\x58\xb9\x10\x58\x71\x25\xff\x73\xbe\xc0\xa8\x96\x40\xb3\xe8\xe8\x54"
         "\xe0\x36\x7f\x4c\xf9\x80\x30\x38\x24\x72\xcf\x24\xce\xc9\x52\x02\x50"
         "\x67\xde\x5b\xa6\xd7\xa7\x23\x2f\x2e\x2b\xa1\x24\xb3\x12\x11\xbf\x52"
         "\x39\x96\xa2\xf9\xe5\x3e\xfa\x40\xf4\xdc\x84\xbe\x71\xa4\xb3\x7a\xd6"
         "\x91\x8d\xe4\x95\x65\x4e\x38\x0a\x1e\x5d\xeb\xc7\x37\x2b\xb2\xaa\x10"
         "\xd7\x5f\xce\x17\x07\x06\x62\x74\xca\xd6\x91\xd4\x24\x65\x53\x2a\x17"
         "\xd4\x3f\x46\x20\xcb\xc4\x78\xb3\xae\xb5\x7b\xda\x6e\x6c\xea\xac\x85"
         "\xcb\x18\x0e\xd5\x6b\x04\x2c\x4e\x37\x58\x3f\xd0\x8f\x35\xef\x63\xcc"
         "\xe5\x3c\x0e\x6c\x11\xd1\xfb\xd0\x73\xab\x5d\xbd\x7a\x74\xc0\xb2\x7b"
         "\xd4\x7e\x38\x30\x12\x22\x2a\x54\xf8\xc8\x4c\x22\x51\x9f\x4f\xa1\x8c"
         "\x32\xe8\x1a\xdd\x51\x47\x54\x71\x72\xd8\x35\x01\xa6\x30\xc9\x0a\x27"
         "\xf1\x7a\x9c\x9a\x79\x67\x72\xb8\x9a\x8b\xea\x8b\x7a\xe2\x59\x5f\xd3"
         "\xef\x7b\xdf\x1c\x5b\x73\xf1\x1c\xe2\x17\x36\xe7\xdc\xf8\xea\x27\x3f"
         "\xf5\x58\xf1\x6d\xa3\x23",
         363);
  syscall(__NR_write, r[0], 0x20000440, 0x16b);
  *(uint64_t*)0x2085dff0 = 0x20e94000;
  *(uint64_t*)0x2085dff8 = 0x10295;
  syscall(__NR_readv, r[0], 0x2085dff0, 1);
}

int main()
{
  syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0);
  for (;;) {
    initialize_tun();
    initialize_netdevices();
    loop();
  }
}