// https://syzkaller.appspot.com/bug?id=a1f5816d285b5e610d7d7f9b04bcfb9732fdc5ef
// 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 <fcntl.h>
#include <linux/capability.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 <sched.h>
#include <signal.h>
#include <stdarg.h>
#include <stdarg.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdio.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/mount.h>
#include <sys/prctl.h>
#include <sys/resource.h>
#include <sys/stat.h>
#include <sys/stat.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/time.h>
#include <sys/wait.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);
}

#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;                                          \
  }

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);
}

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 uintptr_t syz_emit_ethernet(uintptr_t a0, uintptr_t a1)
{

  if (tunfd < 0)
    return (uintptr_t)-1;

  int64_t length = a0;
  char* data = (char*)a1;
  return write(tunfd, data, length);
}

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 bool write_file(const char* file, const char* what, ...)
{
  char buf[1024];
  va_list args;
  va_start(args, what);
  vsnprintf(buf, sizeof(buf), what, args);
  va_end(args);
  buf[sizeof(buf) - 1] = 0;
  int len = strlen(buf);

  int fd = open(file, O_WRONLY | O_CLOEXEC);
  if (fd == -1)
    return false;
  if (write(fd, buf, len) != len) {
    close(fd);
    return false;
  }
  close(fd);
  return true;
}

static int real_uid;
static int real_gid;
static int epid;
static bool etun;
__attribute__((aligned(64 << 10))) static char sandbox_stack[1 << 20];

static int namespace_sandbox_proc(void* arg)
{
  sandbox_common();

  write_file("/proc/self/setgroups", "deny");
  if (!write_file("/proc/self/uid_map", "0 %d 1\n", real_uid))
    fail("write of /proc/self/uid_map failed");
  if (!write_file("/proc/self/gid_map", "0 %d 1\n", real_gid))
    fail("write of /proc/self/gid_map failed");

  setup_tun(epid, etun);

  if (mkdir("./syz-tmp", 0777))
    fail("mkdir(syz-tmp) failed");
  if (mount("", "./syz-tmp", "tmpfs", 0, NULL))
    fail("mount(tmpfs) failed");
  if (mkdir("./syz-tmp/newroot", 0777))
    fail("mkdir failed");
  if (mkdir("./syz-tmp/newroot/dev", 0700))
    fail("mkdir failed");
  if (mount("/dev", "./syz-tmp/newroot/dev", NULL,
            MS_BIND | MS_REC | MS_PRIVATE, NULL))
    fail("mount(dev) failed");
  if (mkdir("./syz-tmp/newroot/proc", 0700))
    fail("mkdir failed");
  if (mount(NULL, "./syz-tmp/newroot/proc", "proc", 0, NULL))
    fail("mount(proc) failed");
  if (mkdir("./syz-tmp/pivot", 0777))
    fail("mkdir failed");
  if (syscall(SYS_pivot_root, "./syz-tmp", "./syz-tmp/pivot")) {
    if (chdir("./syz-tmp"))
      fail("chdir failed");
  } else {
    if (chdir("/"))
      fail("chdir failed");
    if (umount2("./pivot", MNT_DETACH))
      fail("umount failed");
  }
  if (chroot("./newroot"))
    fail("chroot failed");
  if (chdir("/"))
    fail("chdir failed");

  struct __user_cap_header_struct cap_hdr = {};
  struct __user_cap_data_struct cap_data[2] = {};
  cap_hdr.version = _LINUX_CAPABILITY_VERSION_3;
  cap_hdr.pid = getpid();
  if (syscall(SYS_capget, &cap_hdr, &cap_data))
    fail("capget failed");
  cap_data[0].effective &= ~(1 << CAP_SYS_PTRACE);
  cap_data[0].permitted &= ~(1 << CAP_SYS_PTRACE);
  cap_data[0].inheritable &= ~(1 << CAP_SYS_PTRACE);
  if (syscall(SYS_capset, &cap_hdr, &cap_data))
    fail("capset failed");

  loop();
  doexit(1);
}

static int do_sandbox_namespace(int executor_pid, bool enable_tun)
{
  real_uid = getuid();
  real_gid = getgid();
  epid = executor_pid;
  etun = enable_tun;
  mprotect(sandbox_stack, 4096, PROT_NONE);
  return clone(
      namespace_sandbox_proc,
      &sandbox_stack[sizeof(sandbox_stack) - 64],
      CLONE_NEWUSER | CLONE_NEWPID | CLONE_NEWUTS | CLONE_NEWNET, NULL);
}

long r[90];
void loop()
{
  memset(r, -1, sizeof(r));
  r[0] = syscall(__NR_mmap, 0x20000000ul, 0xfff000ul, 0x3ul, 0x32ul,
                 0xfffffffffffffffful, 0x0ul);
  r[1] = syscall(__NR_socket, 0x11ul, 0x803ul, 0x0ul);
  memcpy((void*)0x2008e000, "\x3c\xf6\xda\x23", 4);
  r[3] = syscall(__NR_setsockopt, r[1], 0x107ul, 0xful, 0x2008e000ul,
                 0x4ul);
  *(uint64_t*)0x20f18000 = (uint64_t)0x20e88fa0;
  *(uint32_t*)0x20f18008 = (uint32_t)0x60;
  *(uint64_t*)0x20f18010 = (uint64_t)0x20bee000;
  *(uint64_t*)0x20f18018 = (uint64_t)0x3;
  *(uint64_t*)0x20f18020 = (uint64_t)0x20838000;
  *(uint64_t*)0x20f18028 = (uint64_t)0x10;
  *(uint32_t*)0x20f18030 = (uint32_t)0x42880;
  *(uint16_t*)0x20e88fa0 = (uint16_t)0x27;
  *(uint32_t*)0x20e88fa4 = (uint32_t)0x3;
  *(uint32_t*)0x20e88fa8 = (uint32_t)0x5;
  *(uint32_t*)0x20e88fac = (uint32_t)0x3;
  *(uint8_t*)0x20e88fb0 = (uint8_t)0xad9;
  *(uint8_t*)0x20e88fb1 = (uint8_t)0x0;
  memcpy((void*)0x20e88fb2,
         "\xac\x37\xd7\x00\x19\x29\x62\xf3\xbb\x01\xa4\x62\xdb\xa3\x95"
         "\x59\x9c\x9c\x9b\xe7\x84\x4b\xbe\xfb\xf1\xcc\x00\xa2\x4f\x9c"
         "\x00\x00\x00\x00\xe5\x16\x13\xca\xc2\xd1\x13\x81\x01\x4c\x05"
         "\xca\xe7\x8f\x3e\x86\x1c\x32\x17\x87\xe0\x81\x00\x00\x00\x52"
         "\x2b\x53\x41",
         63);
  *(uint64_t*)0x20e88ff8 = (uint64_t)0x200;
  *(uint64_t*)0x20bee000 = (uint64_t)0x205e5ff6;
  *(uint64_t*)0x20bee008 = (uint64_t)0xa;
  *(uint64_t*)0x20bee010 = (uint64_t)0x20bc1000;
  *(uint64_t*)0x20bee018 = (uint64_t)0x0;
  *(uint64_t*)0x20bee020 = (uint64_t)0x20874000;
  *(uint64_t*)0x20bee028 = (uint64_t)0x9f;
  memcpy((void*)0x205e5ff6, "\xec\x01\x00\x00\x00\x07\x00\x00\xff\x0f",
         10);
  memcpy((void*)0x20874000,
         "\x6b\xfb\xce\xb4\x2d\xc2\x20\xc3\x0f\xd3\x93\x57\xb1\x03\x0b"
         "\xf5\x8c\x98\x38\xbe\x89\x33\x2d\x7f\x9b\xc5\x73\xe1\xb5\xa8"
         "\xb5\x7f\x06\x55\x3c\x9e\xb1\x5b\xf2\x76\x3a\x39\x72\xfe\x23"
         "\x08\x34\x81\x26\x76\x3a\x96\x3a\xab\x30\x68\xf1\x5b\x19\xae"
         "\x71\x28\xd5\x88\x86\xa6\x30\x24\x4d\x79\x20\xfd\x32\x39\x34"
         "\xf5\x7f\x28\x8d\xef\x55\x94\x75\xce\x9a\x2c\x5d\x5d\x49\x82"
         "\xf2\x40\x3c\xdb\x60\x1b\xd5\xbe\x0d\x6d\xb9\x3b\xda\xc0\x54"
         "\x96\x38\xbd\x1f\xee\xb1\xc2\x53\xbf\x28\x92\xfd\xe7\x7f\x64"
         "\x6e\xb6\x38\xe2\x75\x43\x49\x30\xab\x38\x2a\x4a\x41\x22\x36"
         "\xf9\xb9\x1f\x87\xa5\xe3\x68\x87\xe9\x67\x95\x97\x57\xb9\x01"
         "\x3a\x59\x1d\x49\xef\x90\x4b\x6e\xad",
         159);
  *(uint64_t*)0x20838000 = (uint64_t)0x10;
  *(uint32_t*)0x20838008 = (uint32_t)0x1a0;
  *(uint32_t*)0x2083800c = (uint32_t)0x5;
  r[30] = syscall(__NR_sendmsg, r[1], 0x20f18000ul, 0x20000000ul);
  *(uint8_t*)0x20001000 = (uint8_t)0xaa;
  *(uint8_t*)0x20001001 = (uint8_t)0xaa;
  *(uint8_t*)0x20001002 = (uint8_t)0xaa;
  *(uint8_t*)0x20001003 = (uint8_t)0xaa;
  *(uint8_t*)0x20001004 = (uint8_t)0xaa;
  *(uint8_t*)0x20001005 = (uint8_t)0x0;
  memcpy((void*)0x20001006, "\xde\x89\x5d\xb1\x46\x8d", 6);
  *(uint16_t*)0x2000100c = (uint16_t)0xdd86;
  STORE_BY_BITMASK(uint8_t, 0x2000100e, 0x0, 0, 4);
  STORE_BY_BITMASK(uint8_t, 0x2000100e, 0x6, 4, 4);
  memcpy((void*)0x2000100f, "\xaf\x28\xa2", 3);
  *(uint16_t*)0x20001012 = (uint16_t)0x1400;
  *(uint8_t*)0x20001014 = (uint8_t)0x6;
  *(uint8_t*)0x20001015 = (uint8_t)0x0;
  *(uint8_t*)0x20001016 = (uint8_t)0x0;
  *(uint8_t*)0x20001017 = (uint8_t)0x0;
  *(uint8_t*)0x20001018 = (uint8_t)0x0;
  *(uint8_t*)0x20001019 = (uint8_t)0x0;
  *(uint8_t*)0x2000101a = (uint8_t)0x0;
  *(uint8_t*)0x2000101b = (uint8_t)0x0;
  *(uint8_t*)0x2000101c = (uint8_t)0x0;
  *(uint8_t*)0x2000101d = (uint8_t)0x0;
  *(uint8_t*)0x2000101e = (uint8_t)0x0;
  *(uint8_t*)0x2000101f = (uint8_t)0x0;
  *(uint8_t*)0x20001020 = (uint8_t)0x0;
  *(uint8_t*)0x20001021 = (uint8_t)0x0;
  *(uint8_t*)0x20001022 = (uint8_t)0x0;
  *(uint8_t*)0x20001023 = (uint8_t)0x0;
  *(uint8_t*)0x20001024 = (uint8_t)0x0;
  *(uint8_t*)0x20001025 = (uint8_t)0x0;
  *(uint8_t*)0x20001026 = (uint8_t)0xfe;
  *(uint8_t*)0x20001027 = (uint8_t)0x80;
  *(uint8_t*)0x20001028 = (uint8_t)0x0;
  *(uint8_t*)0x20001029 = (uint8_t)0x0;
  *(uint8_t*)0x2000102a = (uint8_t)0x0;
  *(uint8_t*)0x2000102b = (uint8_t)0x0;
  *(uint8_t*)0x2000102c = (uint8_t)0x0;
  *(uint8_t*)0x2000102d = (uint8_t)0x0;
  *(uint8_t*)0x2000102e = (uint8_t)0x0;
  *(uint8_t*)0x2000102f = (uint8_t)0x0;
  *(uint8_t*)0x20001030 = (uint8_t)0x0;
  *(uint8_t*)0x20001031 = (uint8_t)0x0;
  *(uint8_t*)0x20001032 = (uint8_t)0x0;
  *(uint8_t*)0x20001033 = (uint8_t)0x0;
  *(uint8_t*)0x20001034 = (uint8_t)0x0;
  *(uint8_t*)0x20001035 = (uint8_t)0xaa;
  *(uint16_t*)0x20001036 = (uint16_t)0x204e;
  *(uint16_t*)0x20001038 = (uint16_t)0x214e;
  *(uint32_t*)0x2000103a = (uint32_t)0x42424242;
  *(uint32_t*)0x2000103e = (uint32_t)0x42424242;
  STORE_BY_BITMASK(uint8_t, 0x20001042, 0x0, 0, 1);
  STORE_BY_BITMASK(uint8_t, 0x20001042, 0x0, 1, 3);
  STORE_BY_BITMASK(uint8_t, 0x20001042, 0x5, 4, 4);
  *(uint8_t*)0x20001043 = (uint8_t)0x2;
  *(uint16_t*)0x20001044 = (uint16_t)0x0;
  *(uint16_t*)0x20001046 = (uint16_t)0x0;
  *(uint16_t*)0x20001048 = (uint16_t)0x0;
  struct csum_inet csum_88;
  csum_inet_init(&csum_88);
  csum_inet_update(&csum_88, (const uint8_t*)0x20001016, 16);
  csum_inet_update(&csum_88, (const uint8_t*)0x20001026, 16);
  uint32_t csum_88_chunk_2 = 0x14000000;
  csum_inet_update(&csum_88, (const uint8_t*)&csum_88_chunk_2, 4);
  uint32_t csum_88_chunk_3 = 0x6000000;
  csum_inet_update(&csum_88, (const uint8_t*)&csum_88_chunk_3, 4);
  csum_inet_update(&csum_88, (const uint8_t*)0x20001036, 20);
  *(uint16_t*)0x20001046 = csum_inet_digest(&csum_88);
  r[89] = syz_emit_ethernet(0x4aul, 0x20001000ul);
}

int main()
{
  use_temporary_dir();
  int pid = do_sandbox_namespace(0, true);
  int status = 0;
  while (waitpid(pid, &status, __WALL) != pid) {
  }
  return 0;
}