syzkaller-repros/linux/92f036ec29422b5e81ab31f9f23d288f644cc12f.c

// KASAN: use-after-free in l2tp_session_create
// https://syzkaller.appspot.com/bug?id=92f036ec29422b5e81ab31f9f23d288f644cc12f
// status:open
// 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 <linux/capability.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 <sched.h>
#include <signal.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.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/syscall.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <sys/wait.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 <setjmp.h>
#include <signal.h>
#include <stdarg.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.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);
}

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 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
#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 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) {
    int err = errno;
    close(fd);
    errno = err;
    return false;
  }
  close(fd);
  return true;
}

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);

#define CLONE_NEWCGROUP 0x02000000

  if (unshare(CLONE_NEWNS)) {
  }
  if (unshare(CLONE_NEWIPC)) {
  }
  if (unshare(CLONE_NEWCGROUP)) {
  }
  if (unshare(CLONE_NEWUTS)) {
  }
  if (unshare(CLONE_SYSVSEM)) {
  }
}

static int real_uid;
static int real_gid;
__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");

  if (unshare(CLONE_NEWNET))
    fail("unshare(CLONE_NEWNET)");
  initialize_tun();
  initialize_netdevices();

  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");
  unsigned mount_flags = MS_BIND | MS_REC | MS_PRIVATE;
  if (mount("/dev", "./syz-tmp/newroot/dev", NULL, mount_flags, 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/newroot/selinux", 0700))
    fail("mkdir failed");
  const char* selinux_path = "./syz-tmp/newroot/selinux";
  if (mount("/selinux", selinux_path, NULL, mount_flags, NULL)) {
    if (errno != ENOENT)
      fail("mount(/selinux) failed");
    if (mount("/sys/fs/selinux", selinux_path, NULL, mount_flags, NULL) &&
        errno != ENOENT)
      fail("mount(/sys/fs/selinux) failed");
  }
  if (mkdir("./syz-tmp/newroot/sys", 0700))
    fail("mkdir failed");
  if (mount(NULL, "./syz-tmp/newroot/sys", "sysfs", 0, NULL))
    fail("mount(sysfs) 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(void)
{
  int pid;

  real_uid = getuid();
  real_gid = getgid();
  mprotect(sandbox_stack, 4096, PROT_NONE);
  pid =
      clone(namespace_sandbox_proc, &sandbox_stack[sizeof(sandbox_stack) - 64],
            CLONE_NEWUSER | CLONE_NEWPID, 0);
  if (pid < 0)
    fail("sandbox clone failed");
  return pid;
}

static void execute_one();
extern unsigned long long procid;

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

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 int collide;

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);
        if (collide && call % 2)
          break;
        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;
      }
    }
  }
}

uint64_t r[3] = {0xffffffffffffffff, 0xffffffffffffffff, 0x0};
unsigned long long procid;
void execute_call(int call)
{
  long res;
  switch (call) {
  case 0:
    NONFAILING(*(uint32_t*)0x20000380 = 0x80);
    syscall(__NR_accept4, -1, 0x200003c0, 0x20000380, 0);
    break;
  case 1:
    syscall(__NR_mmap, 0x20000000, 0xe7e000, 0, 0x8010, -1, 0);
    break;
  case 2:
    res = syscall(__NR_socket, 0xa, 2, 0);
    if (res != -1)
      r[0] = res;
    break;
  case 3:
    res = syscall(__NR_socket, 0x18, 1, 1);
    if (res != -1)
      r[1] = res;
    break;
  case 4:
    NONFAILING(*(uint16_t*)0x205fafd2 = 0x18);
    NONFAILING(*(uint32_t*)0x205fafd4 = 1);
    NONFAILING(*(uint32_t*)0x205fafd8 = 0);
    NONFAILING(*(uint32_t*)0x205fafdc = r[0]);
    NONFAILING(*(uint16_t*)0x205fafe0 = 2);
    NONFAILING(*(uint16_t*)0x205fafe2 = htobe16(0));
    NONFAILING(*(uint32_t*)0x205fafe4 = htobe32(0xe0000002));
    NONFAILING(*(uint8_t*)0x205fafe8 = 0);
    NONFAILING(*(uint8_t*)0x205fafe9 = 0);
    NONFAILING(*(uint8_t*)0x205fafea = 0);
    NONFAILING(*(uint8_t*)0x205fafeb = 0);
    NONFAILING(*(uint8_t*)0x205fafec = 0);
    NONFAILING(*(uint8_t*)0x205fafed = 0);
    NONFAILING(*(uint8_t*)0x205fafee = 0);
    NONFAILING(*(uint8_t*)0x205fafef = 0);
    NONFAILING(*(uint32_t*)0x205faff0 = 4);
    NONFAILING(*(uint32_t*)0x205faff4 = 0);
    NONFAILING(*(uint32_t*)0x205faff8 = 2);
    NONFAILING(*(uint32_t*)0x205faffc = 0);
    syscall(__NR_connect, r[1], 0x205fafd2, 0x2e);
    break;
  case 5:
    syscall(__NR_close, r[0]);
    break;
  case 6:
    NONFAILING(*(uint64_t*)0x2037ffc8 = 0x209dd000);
    NONFAILING(*(uint16_t*)0x209dd000 = 0x10);
    NONFAILING(*(uint16_t*)0x209dd002 = 0);
    NONFAILING(*(uint32_t*)0x209dd004 = 0);
    NONFAILING(*(uint32_t*)0x209dd008 = 0);
    NONFAILING(*(uint32_t*)0x2037ffd0 = 0xc);
    NONFAILING(*(uint64_t*)0x2037ffd8 = 0x202ceff0);
    NONFAILING(*(uint64_t*)0x202ceff0 = 0x2097b000);
    NONFAILING(*(uint32_t*)0x2097b000 = 0x10);
    NONFAILING(*(uint16_t*)0x2097b004 = 0x14);
    NONFAILING(*(uint16_t*)0x2097b006 = 0x200);
    NONFAILING(*(uint32_t*)0x2097b008 = 0);
    NONFAILING(*(uint32_t*)0x2097b00c = 3);
    NONFAILING(*(uint64_t*)0x202ceff8 = 0xfff1);
    NONFAILING(*(uint64_t*)0x2037ffe0 = 1);
    NONFAILING(*(uint64_t*)0x2037ffe8 = 0);
    NONFAILING(*(uint64_t*)0x2037fff0 = 0);
    NONFAILING(*(uint32_t*)0x2037fff8 = 0x8820);
    syscall(__NR_sendmsg, r[1], 0x2037ffc8, 0);
    break;
  case 7:
    NONFAILING(
        memcpy((void*)0x20000a80,
               "\x61\x73\x79\x6d\x6d\x65\x74\x72\x69\x63\x00\x41\x47\x2e\x8b"
               "\x63\x7f\x55\xf6\x94\xfc\xef\x0e\x58\xfc\x2a\xc9\x24\xf9\xdd"
               "\x8a\xdd\xbd\x7b\xdb\x02\x00\x97\x65\x8e\x76\x51\x73\x8b\x0e"
               "\x4a\xb8\x18\xc6\xe7\x6c\x0d\x07\x5a\x9a\xaf\xcc\xb8\xdf\xa4"
               "\x63\xc0\xe0\x41\x94\xee\x37\x28\x4e\x41\x41\x93\xd8\x60",
               74));
    NONFAILING(*(uint8_t*)0x20000b00 = 0x73);
    NONFAILING(*(uint8_t*)0x20000b01 = 0x79);
    NONFAILING(*(uint8_t*)0x20000b02 = 0x7a);
    NONFAILING(*(uint8_t*)0x20000b03 = 0x20 + procid * 4);
    NONFAILING(*(uint8_t*)0x20000b04 = 0);
    syscall(__NR_add_key, 0x20000a80, 0x20000b00, 0x20000800, 0, 0xfffffffc);
    break;
  case 8:
    NONFAILING(*(uint32_t*)0x20000240 = 3);
    NONFAILING(*(uint64_t*)0x20000248 = 0x20000200);
    res = syscall(__NR_ioctl, 0xffffff9c, 0xc0086426, 0x20000240);
    if (res != -1)
      NONFAILING(r[2] = *(uint32_t*)0x20000210);
    break;
  case 9:
    NONFAILING(*(uint32_t*)0x20000280 = r[2]);
    NONFAILING(*(uint32_t*)0x20000284 = 2);
    syscall(__NR_ioctl, -1, 0xc0086421, 0x20000280);
    break;
  case 10:
    NONFAILING(memcpy((void*)0x20000180, "./file0", 8));
    NONFAILING(memcpy((void*)0x20000200, "./file0", 8));
    syscall(__NR_linkat, -1, 0x20000180, -1, 0x20000200, 0);
    break;
  case 11:
    NONFAILING(*(uint64_t*)0x20360000 = 0);
    NONFAILING(*(uint32_t*)0x20360008 = 0);
    NONFAILING(*(uint64_t*)0x20360010 = 0x2035d000);
    NONFAILING(*(uint64_t*)0x2035d000 = 0x2033c000);
    NONFAILING(*(uint8_t*)0x2033c000 = 2);
    NONFAILING(*(uint8_t*)0x2033c001 = 0xd);
    NONFAILING(*(uint8_t*)0x2033c002 = 0);
    NONFAILING(*(uint8_t*)0x2033c003 = 0);
    NONFAILING(*(uint16_t*)0x2033c004 = 0x10);
    NONFAILING(*(uint16_t*)0x2033c006 = 0);
    NONFAILING(*(uint32_t*)0x2033c008 = 0);
    NONFAILING(*(uint32_t*)0x2033c00c = 0);
    NONFAILING(*(uint16_t*)0x2033c010 = 3);
    NONFAILING(*(uint16_t*)0x2033c012 = 6);
    NONFAILING(*(uint8_t*)0x2033c014 = 0);
    NONFAILING(*(uint8_t*)0x2033c015 = 0);
    NONFAILING(*(uint16_t*)0x2033c016 = 0);
    NONFAILING(*(uint16_t*)0x2033c018 = 2);
    NONFAILING(*(uint16_t*)0x2033c01a = htobe16(0));
    NONFAILING(*(uint32_t*)0x2033c01c = htobe32(0x7f000001));
    NONFAILING(*(uint8_t*)0x2033c020 = 0);
    NONFAILING(*(uint8_t*)0x2033c021 = 0);
    NONFAILING(*(uint8_t*)0x2033c022 = 0);
    NONFAILING(*(uint8_t*)0x2033c023 = 0);
    NONFAILING(*(uint8_t*)0x2033c024 = 0);
    NONFAILING(*(uint8_t*)0x2033c025 = 0);
    NONFAILING(*(uint8_t*)0x2033c026 = 0);
    NONFAILING(*(uint8_t*)0x2033c027 = 0);
    NONFAILING(*(uint16_t*)0x2033c028 = 3);
    NONFAILING(*(uint16_t*)0x2033c02a = 5);
    NONFAILING(*(uint8_t*)0x2033c02c = 0);
    NONFAILING(*(uint8_t*)0x2033c02d = 0);
    NONFAILING(*(uint16_t*)0x2033c02e = 0);
    NONFAILING(*(uint16_t*)0x2033c030 = 2);
    NONFAILING(*(uint16_t*)0x2033c032 = htobe16(0));
    NONFAILING(*(uint32_t*)0x2033c034 = htobe32(0));
    NONFAILING(*(uint8_t*)0x2033c038 = 0);
    NONFAILING(*(uint8_t*)0x2033c039 = 0);
    NONFAILING(*(uint8_t*)0x2033c03a = 0);
    NONFAILING(*(uint8_t*)0x2033c03b = 0);
    NONFAILING(*(uint8_t*)0x2033c03c = 0);
    NONFAILING(*(uint8_t*)0x2033c03d = 0);
    NONFAILING(*(uint8_t*)0x2033c03e = 0);
    NONFAILING(*(uint8_t*)0x2033c03f = 0);
    NONFAILING(*(uint16_t*)0x2033c040 = 8);
    NONFAILING(*(uint16_t*)0x2033c042 = 0x12);
    NONFAILING(*(uint16_t*)0x2033c044 = 2);
    NONFAILING(*(uint8_t*)0x2033c046 = 1);
    NONFAILING(*(uint8_t*)0x2033c047 = 0);
    NONFAILING(*(uint32_t*)0x2033c048 = 0);
    NONFAILING(*(uint32_t*)0x2033c04c = 0);
    NONFAILING(*(uint16_t*)0x2033c050 = 0x30);
    NONFAILING(*(uint16_t*)0x2033c052 = 0);
    NONFAILING(*(uint8_t*)0x2033c054 = 3);
    NONFAILING(*(uint8_t*)0x2033c055 = 3);
    NONFAILING(*(uint16_t*)0x2033c056 = 0);
    NONFAILING(*(uint32_t*)0x2033c058 = 0);
    NONFAILING(*(uint32_t*)0x2033c05c = 0);
    NONFAILING(*(uint8_t*)0x2033c060 = -1);
    NONFAILING(*(uint8_t*)0x2033c061 = 1);
    NONFAILING(*(uint8_t*)0x2033c062 = 0);
    NONFAILING(*(uint8_t*)0x2033c063 = 0);
    NONFAILING(*(uint8_t*)0x2033c064 = 0);
    NONFAILING(*(uint8_t*)0x2033c065 = 0);
    NONFAILING(*(uint8_t*)0x2033c066 = 0);
    NONFAILING(*(uint8_t*)0x2033c067 = 0);
    NONFAILING(*(uint8_t*)0x2033c068 = 0);
    NONFAILING(*(uint8_t*)0x2033c069 = 0);
    NONFAILING(*(uint8_t*)0x2033c06a = 0);
    NONFAILING(*(uint8_t*)0x2033c06b = 0);
    NONFAILING(*(uint8_t*)0x2033c06c = 0);
    NONFAILING(*(uint8_t*)0x2033c06d = 0);
    NONFAILING(*(uint8_t*)0x2033c06e = 0);
    NONFAILING(*(uint8_t*)0x2033c06f = 1);
    NONFAILING(*(uint8_t*)0x2033c070 = 0);
    NONFAILING(*(uint8_t*)0x2033c071 = 0);
    NONFAILING(*(uint8_t*)0x2033c072 = 0);
    NONFAILING(*(uint8_t*)0x2033c073 = 0);
    NONFAILING(*(uint8_t*)0x2033c074 = 0);
    NONFAILING(*(uint8_t*)0x2033c075 = 0);
    NONFAILING(*(uint8_t*)0x2033c076 = 0);
    NONFAILING(*(uint8_t*)0x2033c077 = 0);
    NONFAILING(*(uint8_t*)0x2033c078 = 0);
    NONFAILING(*(uint8_t*)0x2033c079 = 0);
    NONFAILING(*(uint8_t*)0x2033c07a = -1);
    NONFAILING(*(uint8_t*)0x2033c07b = -1);
    NONFAILING(*(uint32_t*)0x2033c07c = htobe32(0xe0000001));
    NONFAILING(*(uint64_t*)0x2035d008 = 0x80);
    NONFAILING(*(uint64_t*)0x20360018 = 1);
    NONFAILING(*(uint64_t*)0x20360020 = 0);
    NONFAILING(*(uint64_t*)0x20360028 = 0);
    NONFAILING(*(uint32_t*)0x20360030 = 0);
    syscall(__NR_sendmsg, -1, 0x20360000, 0);
    break;
  case 12:
    NONFAILING(memcpy((void*)0x20000700, "ceph", 5));
    NONFAILING(*(uint8_t*)0x20000740 = 0x73);
    NONFAILING(*(uint8_t*)0x20000741 = 0x79);
    NONFAILING(*(uint8_t*)0x20000742 = 0x7a);
    NONFAILING(*(uint8_t*)0x20000743 = 0x23 + procid * 4);
    NONFAILING(*(uint8_t*)0x20000744 = 0);
    NONFAILING(memcpy((void*)0x20000780, "eth0ppp0", 9));
    syscall(__NR_request_key, 0x20000700, 0x20000740, 0x20000780, 0xfffffff8);
    break;
  case 13:
    syscall(__NR_keyctl, 0x14, 0, 0x200006c0, 0x200000000000006c, 0);
    break;
  case 14:
    NONFAILING(*(uint64_t*)0x20000a40 = 0x20000940);
    NONFAILING(*(uint16_t*)0x20000940 = 0x10);
    NONFAILING(*(uint16_t*)0x20000942 = 0);
    NONFAILING(*(uint32_t*)0x20000944 = 0);
    NONFAILING(*(uint32_t*)0x20000948 = 0x100010);
    NONFAILING(*(uint32_t*)0x20000a48 = 0xc);
    NONFAILING(*(uint64_t*)0x20000a50 = 0x20000a00);
    NONFAILING(*(uint64_t*)0x20000a00 = 0x20000580);
    NONFAILING(*(uint64_t*)0x20000a08 = 1);
    NONFAILING(*(uint64_t*)0x20000a58 = 1);
    NONFAILING(*(uint64_t*)0x20000a60 = 0);
    NONFAILING(*(uint64_t*)0x20000a68 = 0);
    NONFAILING(*(uint32_t*)0x20000a70 = 1);
    syscall(__NR_sendmsg, -1, 0x20000a40, 0xc000);
    break;
  case 15:
    syscall(__NR_setns, r[1], 0x4000000);
    break;
  }
}

void execute_one()
{
  execute(16);
  collide = 1;
  execute(16);
}

int main()
{
  syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0);
  char* cwd = get_current_dir_name();
  for (procid = 0; procid < 8; procid++) {
    if (fork() == 0) {
      install_segv_handler();
      for (;;) {
        if (chdir(cwd))
          fail("failed to chdir");
        use_temporary_dir();
        int pid = do_sandbox_namespace();
        int status = 0;
        while (waitpid(pid, &status, __WALL) != pid) {
        }
      }
    }
  }
  sleep(1000000);
  return 0;
}