setup_tun

// autogenerated by syzkaller (http://github.com/google/syzkaller)

#ifndef __NR_mmap
#define __NR_mmap 9
#endif
#ifndef __NR_openat
#define __NR_openat 257
#endif
#ifndef __NR_getsockopt
#define __NR_getsockopt 55
#endif
#ifndef __NR_ioctl
#define __NR_ioctl 16
#endif
#ifndef __NR_setsockopt
#define __NR_setsockopt 54
#endif
#ifndef __NR_socketpair
#define __NR_socketpair 53
#endif
#ifndef __NR_getpid
#define __NR_getpid 39
#endif
#ifndef __NR_ptrace
#define __NR_ptrace 101
#endif
#ifndef __NR_get_robust_list
#define __NR_get_robust_list 274
#endif
#ifndef __NR_getpeername
#define __NR_getpeername 52
#endif
#ifndef __NR_fcntl
#define __NR_fcntl 72
#endif

#define _GNU_SOURCE

#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/mount.h>
#include <sys/prctl.h>
#include <sys/resource.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/wait.h>

#include <linux/capability.h>
#include <linux/if.h>
#include <linux/if_tun.h>
#include <linux/kvm.h>
#include <linux/sched.h>
#include <net/if_arp.h>

#include <assert.h>
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <grp.h>
#include <pthread.h>
#include <setjmp.h>
#include <signal.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

const int kFailStatus = 67;
const int kErrorStatus = 68;
const int kRetryStatus = 69;

__attribute__((noreturn)) void doexit(int status)
{
  volatile unsigned i;
  syscall(__NR_exit_group, status);
  for (i = 0;; i++) {
  }
}

__attribute__((noreturn)) 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 ? kRetryStatus : kFailStatus);
}

__attribute__((noreturn)) void exitf(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(kRetryStatus);
}

static int flag_debug;

void debug(const char* msg, ...)
{
  if (!flag_debug)
    return;
  va_list args;
  va_start(args, msg);
  vfprintf(stdout, msg, args);
  va_end(args);
  fflush(stdout);
}

__thread int skip_segv;
__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)) {
    debug("SIGSEGV on %p, skipping\n", addr);
    _longjmp(segv_env, 1);
  }
  debug("SIGSEGV on %p, exiting\n", addr);
  doexit(sig);
  for (;;) {
  }
}

static void install_segv_handler()
{
  struct sigaction sa;
  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);               \
  }

#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 uintptr_t execute_syscall(int nr, uintptr_t a0, uintptr_t a1,
                                 uintptr_t a2, uintptr_t a3,
                                 uintptr_t a4, uintptr_t a5,
                                 uintptr_t a6, uintptr_t a7,
                                 uintptr_t a8)
{
  switch (nr) {
  default:
    return syscall(nr, a0, a1, a2, a3, a4, a5);
  }
}

static void setup_main_process()
{
  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);
  install_segv_handler();

  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 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 = 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 int do_sandbox_setuid(int executor_pid, bool enable_tun)
{
  int pid = fork();
  if (pid)
    return pid;

  sandbox_common();
  setup_tun(executor_pid, enable_tun);

  const int nobody = 65534;
  if (setgroups(0, NULL))
    fail("failed to setgroups");
  if (syscall(SYS_setresgid, nobody, nobody, nobody))
    fail("failed to setresgid");
  if (syscall(SYS_setresuid, nobody, nobody, nobody))
    fail("failed to setresuid");

  loop();
  doexit(1);
}

static void remove_dir(const char* dir)
{
  DIR* dp;
  struct dirent* ep;
  int iter = 0;
retry:
  dp = opendir(dir);
  if (dp == NULL) {
    if (errno == EMFILE) {
      exitf("opendir(%s) failed due to NOFILE, exiting");
    }
    exitf("opendir(%s) failed", dir);
  }
  while ((ep = readdir(dp))) {
    if (strcmp(ep->d_name, ".") == 0 || strcmp(ep->d_name, "..") == 0)
      continue;
    char filename[FILENAME_MAX];
    snprintf(filename, sizeof(filename), "%s/%s", dir, ep->d_name);
    struct stat st;
    if (lstat(filename, &st))
      exitf("lstat(%s) failed", filename);
    if (S_ISDIR(st.st_mode)) {
      remove_dir(filename);
      continue;
    }
    int i;
    for (i = 0;; i++) {
      debug("unlink(%s)\n", filename);
      if (unlink(filename) == 0)
        break;
      if (errno == EROFS) {
        debug("ignoring EROFS\n");
        break;
      }
      if (errno != EBUSY || i > 100)
        exitf("unlink(%s) failed", filename);
      debug("umount(%s)\n", filename);
      if (umount2(filename, MNT_DETACH))
        exitf("umount(%s) failed", filename);
    }
  }
  closedir(dp);
  int i;
  for (i = 0;; i++) {
    debug("rmdir(%s)\n", dir);
    if (rmdir(dir) == 0)
      break;
    if (i < 100) {
      if (errno == EROFS) {
        debug("ignoring EROFS\n");
        break;
      }
      if (errno == EBUSY) {
        debug("umount(%s)\n", dir);
        if (umount2(dir, MNT_DETACH))
          exitf("umount(%s) failed", dir);
        continue;
      }
      if (errno == ENOTEMPTY) {
        if (iter < 100) {
          iter++;
          goto retry;
        }
      }
    }
    exitf("rmdir(%s) failed", dir);
  }
}

static uint64_t current_time_ms()
{
  struct timespec ts;

  if (clock_gettime(CLOCK_MONOTONIC, &ts))
    fail("clock_gettime failed");
  return (uint64_t)ts.tv_sec * 1000 + (uint64_t)ts.tv_nsec / 1000000;
}

static void test();

void loop()
{
  int iter;
  for (iter = 0;; iter++) {
    char cwdbuf[256];
    sprintf(cwdbuf, "./%d", iter);
    if (mkdir(cwdbuf, 0777))
      fail("failed to mkdir");
    int pid = fork();
    if (pid < 0)
      fail("clone failed");
    if (pid == 0) {
      prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
      setpgrp();
      if (chdir(cwdbuf))
        fail("failed to chdir");
      test();
      doexit(0);
    }
    int status = 0;
    uint64_t start = current_time_ms();
    for (;;) {
      int res = waitpid(-1, &status, __WALL | WNOHANG);
      if (res == pid)
        break;
      usleep(1000);
      if (current_time_ms() - start > 5 * 1000) {
        kill(-pid, SIGKILL);
        kill(pid, SIGKILL);
        while (waitpid(-1, &status, __WALL) != pid) {
        }
        break;
      }
    }
    remove_dir(cwdbuf);
  }
}

long r[88];
void* thr(void* arg)
{
  switch ((long)arg) {
  case 0:
    r[0] = execute_syscall(__NR_getpid, 0, 0, 0, 0, 0, 0, 0, 0, 0);
    break;
  case 1:
    r[1] = execute_syscall(__NR_ptrace, 0x5ul, r[0], 0x20de0ff8ul,
                           0x5ul, 0, 0, 0, 0, 0);
    break;
  case 2:
    r[2] =
        execute_syscall(__NR_mmap, 0x20000000ul, 0x1000ul, 0x3ul,
                        0x32ul, 0xfffffffffffffffful, 0x0ul, 0, 0, 0);
    break;
  case 3:
    r[3] =
        execute_syscall(__NR_mmap, 0x20000000ul, 0x1000ul, 0x3ul,
                        0x32ul, 0xfffffffffffffffful, 0x0ul, 0, 0, 0);
    break;
  case 4:
    NONFAILING(*(uint64_t*)0x20000000 = (uint64_t)0x20b88000);
    NONFAILING(*(uint64_t*)0x20000ff8 = (uint64_t)0x18);
    r[6] = execute_syscall(__NR_get_robust_list, r[0], 0x20000000ul,
                           0x20000ff8ul, 0, 0, 0, 0, 0, 0);
    break;
  case 5:
    NONFAILING(memcpy((void*)0x20000ff7,
                      "\x2f\x64\x65\x76\x2f\x70\x70\x70\x00", 9));
    r[8] =
        execute_syscall(__NR_openat, 0xffffffffffffff9cul, 0x20000ff7ul,
                        0x84200ul, 0x0ul, 0, 0, 0, 0, 0);
    break;
  case 6:
    r[9] =
        execute_syscall(__NR_mmap, 0x20001000ul, 0x1000ul, 0x3ul,
                        0x32ul, 0xfffffffffffffffful, 0x0ul, 0, 0, 0);
    break;
  case 7:
    NONFAILING(*(uint32_t*)0x20000000 = (uint32_t)0x4);
    NONFAILING(*(uint32_t*)0x20000004 = (uint32_t)0xfff);
    NONFAILING(*(uint32_t*)0x20000008 = (uint32_t)0x800000000);
    NONFAILING(*(uint32_t*)0x20001000 = (uint32_t)0xc);
    r[14] = execute_syscall(__NR_getsockopt, r[8], 0x84ul, 0x10ul,
                            0x20000000ul, 0x20001000ul, 0, 0, 0, 0);
    break;
  case 8:
    r[15] =
        execute_syscall(__NR_mmap, 0x20002000ul, 0x1000ul, 0x3ul,
                        0x32ul, 0xfffffffffffffffful, 0x0ul, 0, 0, 0);
    break;
  case 9:
    r[16] = execute_syscall(__NR_ioctl, r[8], 0x540ful, 0x20002000ul, 0,
                            0, 0, 0, 0, 0);
    break;
  case 10:
    r[17] =
        execute_syscall(__NR_mmap, 0x20003000ul, 0x1000ul, 0x3ul,
                        0x32ul, 0xfffffffffffffffful, 0x0ul, 0, 0, 0);
    break;
  case 11:
    NONFAILING(*(uint32_t*)0x20003f10 = (uint32_t)0x0);
    NONFAILING(*(uint32_t*)0x20003f20 = (uint32_t)0x100007f);
    NONFAILING(*(uint16_t*)0x20003f30 = (uint16_t)0x214e);
    NONFAILING(*(uint16_t*)0x20003f32 = (uint16_t)0x5a8fb113);
    NONFAILING(*(uint16_t*)0x20003f34 = (uint16_t)0x224e);
    NONFAILING(*(uint16_t*)0x20003f36 = (uint16_t)0x0);
    NONFAILING(*(uint16_t*)0x20003f38 = (uint16_t)0x9);
    NONFAILING(*(uint8_t*)0x20003f3a = (uint8_t)0x40);
    NONFAILING(*(uint8_t*)0x20003f3b = (uint8_t)0x0);
    NONFAILING(*(uint8_t*)0x20003f3c = (uint8_t)0x7ff);
    NONFAILING(*(uint32_t*)0x20003f40 = (uint32_t)0x1000);
    NONFAILING(*(uint32_t*)0x20003f44 = (uint32_t)0xfff);
    NONFAILING(*(uint64_t*)0x20003f48 = (uint64_t)0x7);
    NONFAILING(*(uint64_t*)0x20003f50 = (uint64_t)0xfff);
    NONFAILING(*(uint64_t*)0x20003f58 = (uint64_t)0x1);
    NONFAILING(*(uint64_t*)0x20003f60 = (uint64_t)0x3);
    NONFAILING(*(uint64_t*)0x20003f68 = (uint64_t)0x0);
    NONFAILING(*(uint64_t*)0x20003f70 = (uint64_t)0x3);
    NONFAILING(*(uint64_t*)0x20003f78 = (uint64_t)0xffff);
    NONFAILING(*(uint64_t*)0x20003f80 = (uint64_t)0x100);
    NONFAILING(*(uint64_t*)0x20003f88 = (uint64_t)0x7e3);
    NONFAILING(*(uint64_t*)0x20003f90 = (uint64_t)0x64be);
    NONFAILING(*(uint64_t*)0x20003f98 = (uint64_t)0x3);
    NONFAILING(*(uint64_t*)0x20003fa0 = (uint64_t)0x6);
    NONFAILING(*(uint32_t*)0x20003fa8 = (uint32_t)0x9);
    NONFAILING(*(uint32_t*)0x20003fac = (uint32_t)0x3);
    NONFAILING(*(uint8_t*)0x20003fb0 = (uint8_t)0x80000000);
    NONFAILING(*(uint8_t*)0x20003fb1 = (uint8_t)0x8);
    NONFAILING(*(uint8_t*)0x20003fb2 = (uint8_t)0x1);
    NONFAILING(*(uint8_t*)0x20003fb3 = (uint8_t)0x2f98);
    NONFAILING(*(uint64_t*)0x20003fb8 = (uint64_t)0x0);
    NONFAILING(*(uint64_t*)0x20003fc0 = (uint64_t)0x0);
    NONFAILING(*(uint32_t*)0x20003fc8 = (uint32_t)0x1000000000000000);
    NONFAILING(*(uint8_t*)0x20003fcc = (uint8_t)0x81);
    NONFAILING(*(uint16_t*)0x20003fd0 = (uint16_t)0xba);
    NONFAILING(*(uint32_t*)0x20003fd8 = (uint32_t)0x100007f);
    NONFAILING(*(uint32_t*)0x20003fe8 = (uint32_t)0x5f);
    NONFAILING(*(uint8_t*)0x20003fec = (uint8_t)0x8);
    NONFAILING(*(uint8_t*)0x20003fed = (uint8_t)0x5);
    NONFAILING(*(uint8_t*)0x20003fee = (uint8_t)0x18000000000);
    NONFAILING(*(uint32_t*)0x20003ff0 = (uint32_t)0x3);
    NONFAILING(*(uint32_t*)0x20003ff4 = (uint32_t)0x7);
    NONFAILING(*(uint32_t*)0x20003ff8 = (uint32_t)0x6);
    r[61] = execute_syscall(__NR_setsockopt, r[8], 0x0ul, 0x10ul,
                            0x20003f10ul, 0xf0ul, 0, 0, 0, 0);
    break;
  case 12:
    r[62] = execute_syscall(__NR_ioctl, r[8], 0x4b4eul, 0x8ul, 0, 0, 0,
                            0, 0, 0);
    break;
  case 13:
    r[63] =
        execute_syscall(__NR_mmap, 0x20004000ul, 0x1000ul, 0x3ul,
                        0x32ul, 0xfffffffffffffffful, 0x0ul, 0, 0, 0);
    break;
  case 14:
    NONFAILING(*(uint32_t*)0x20003000 = (uint32_t)0x4);
    r[65] = execute_syscall(__NR_getsockopt, r[8], 0x84ul, 0xcul,
                            0x20004000ul, 0x20003000ul, 0, 0, 0, 0);
    break;
  case 15:
    r[66] = execute_syscall(__NR_ioctl, r[8], 0x4b32ul, 0x5ul, 0, 0, 0,
                            0, 0, 0);
    break;
  case 16:
    r[67] =
        execute_syscall(__NR_mmap, 0x20005000ul, 0x1000ul, 0x3ul,
                        0x32ul, 0xfffffffffffffffful, 0x0ul, 0, 0, 0);
    break;
  case 17:
    NONFAILING(*(uint32_t*)0x20001000 = (uint32_t)0x4);
    r[69] = execute_syscall(__NR_getsockopt, r[8], 0x84ul, 0x21ul,
                            0x20005ffcul, 0x20001000ul, 0, 0, 0, 0);
    break;
  case 18:
    NONFAILING(*(uint32_t*)0x20004000 = (uint32_t)0x1);
    r[71] = execute_syscall(__NR_setsockopt, r[8], 0x84ul, 0x7ul,
                            0x20004000ul, 0x4ul, 0, 0, 0, 0);
    break;
  case 19:
    r[72] =
        execute_syscall(__NR_mmap, 0x20006000ul, 0x1000ul, 0x3ul,
                        0x32ul, 0xfffffffffffffffful, 0x0ul, 0, 0, 0);
    break;
  case 20:
    NONFAILING(*(uint32_t*)0x20003ffc = (uint32_t)0x10);
    r[74] = execute_syscall(__NR_getpeername, r[8], 0x20006000ul,
                            0x20003ffcul, 0, 0, 0, 0, 0, 0);
    break;
  case 21:
    NONFAILING(*(uint32_t*)0x20002ffc = (uint32_t)0x85);
    r[76] = execute_syscall(__NR_setsockopt, r[8], 0x84ul, 0xcul,
                            0x20002ffcul, 0x4ul, 0, 0, 0, 0);
    break;
  case 22:
    NONFAILING(*(uint32_t*)0x20003ff8 = r[8]);
    NONFAILING(*(uint32_t*)0x20003ffc = (uint32_t)0x0);
    r[79] = execute_syscall(__NR_ioctl, r[8], 0x400443c8ul,
                            0x20003ff8ul, 0, 0, 0, 0, 0, 0);
    break;
  case 23:
    r[80] = execute_syscall(__NR_ioctl, r[8], 0x2403ul, 0x9ul, 0, 0, 0,
                            0, 0, 0);
    break;
  case 24:
    r[81] = execute_syscall(__NR_fcntl, r[8], 0x1ul, 0x8ul, 0, 0, 0, 0,
                            0, 0);
    break;
  case 25:
    r[82] =
        execute_syscall(__NR_mmap, 0x20007000ul, 0x1000ul, 0x3ul,
                        0x32ul, 0xfffffffffffffffful, 0x0ul, 0, 0, 0);
    break;
  case 26:
    r[83] =
        execute_syscall(__NR_mmap, 0x20007000ul, 0x1000ul, 0x3ul,
                        0x32ul, 0xfffffffffffffffful, 0x0ul, 0, 0, 0);
    break;
  case 27:
    NONFAILING(*(uint32_t*)0x20007000 = (uint32_t)0x8);
    r[85] = execute_syscall(__NR_getpeername, r[8], 0x20007ff8ul,
                            0x20007000ul, 0, 0, 0, 0, 0, 0);
    break;
  case 28:
    r[86] = execute_syscall(__NR_fcntl, r[8], 0x10ul, 0x20004000ul, 0,
                            0, 0, 0, 0, 0);
    break;
  case 29:
    r[87] = execute_syscall(__NR_socketpair, 0xaul, 0x0ul, 0x4ul,
                            0x20007000ul, 0, 0, 0, 0, 0);
    break;
  }
  return 0;
}

void test()
{
  long i;
  pthread_t th[60];

  memset(r, -1, sizeof(r));
  srand(getpid());
  for (i = 0; i < 30; i++) {
    pthread_create(&th[i], 0, thr, (void*)i);
    usleep(10000);
  }
  for (i = 0; i < 30; i++) {
    pthread_create(&th[30 + i], 0, thr, (void*)i);
    if (rand() % 2)
      usleep(rand() % 10000);
  }
  usleep(100000);
}

int main()
{
  int i;
  for (i = 0; i < 8; i++) {
    if (fork() == 0) {
      setup_main_process();
      do_sandbox_setuid(i, false);
      return 0;
    }
  }
  sleep(1000000);
  return 0;
}