// https://syzkaller.appspot.com/bug?id=af4e096cd916465ae6a9d7d2b680fc321d75e60e
// autogenerated by syzkaller (https://github.com/google/syzkaller)

#define _GNU_SOURCE

#include <endian.h>
#include <errno.h>
#include <fcntl.h>
#include <sched.h>
#include <setjmp.h>
#include <signal.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.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/wait.h>
#include <unistd.h>

#include <linux/capability.h>

static __thread int skip_segv;
static __thread jmp_buf segv_env;

static void segv_handler(int sig, siginfo_t* info, void* ctx)
{
  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);
  }
  exit(sig);
}

static void install_segv_handler(void)
{
  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 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 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)) {
  }
  typedef struct {
    const char* name;
    const char* value;
  } sysctl_t;
  static const sysctl_t sysctls[] = {
      {"/proc/sys/kernel/shmmax", "16777216"},
      {"/proc/sys/kernel/shmall", "536870912"},
      {"/proc/sys/kernel/shmmni", "1024"},
      {"/proc/sys/kernel/msgmax", "8192"},
      {"/proc/sys/kernel/msgmni", "1024"},
      {"/proc/sys/kernel/msgmnb", "1024"},
      {"/proc/sys/kernel/sem", "1024 1048576 500 1024"},
  };
  unsigned i;
  for (i = 0; i < sizeof(sysctls) / sizeof(sysctls[0]); i++)
    write_file(sysctls[i].name, sysctls[i].value);
}

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

static void drop_caps(void)
{
  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))
    exit(1);
  const int drop = (1 << CAP_SYS_PTRACE) | (1 << CAP_SYS_NICE);
  cap_data[0].effective &= ~drop;
  cap_data[0].permitted &= ~drop;
  cap_data[0].inheritable &= ~drop;
  if (syscall(SYS_capset, &cap_hdr, &cap_data))
    exit(1);
}

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();
  drop_caps();
  if (unshare(CLONE_NEWNET)) {
  }
  loop();
  exit(1);
}

static void setup_binfmt_misc()
{
  if (mount(0, "/proc/sys/fs/binfmt_misc", "binfmt_misc", 0, 0)) {
  }
  write_file("/proc/sys/fs/binfmt_misc/register", ":syz0:M:0:\x01::./file0:");
  write_file("/proc/sys/fs/binfmt_misc/register",
             ":syz1:M:1:\x02::./file0:POC");
}

uint64_t r[1] = {0xffffffffffffffff};

void loop(void)
{
  intptr_t res = 0;
  NONFAILING(memcpy((void*)0x20000180, "/dev/fb0\000", 9));
  res = syscall(__NR_openat, 0xffffffffffffff9cul, 0x20000180ul, 0ul, 0ul);
  if (res != -1)
    r[0] = res;
  NONFAILING(*(uint32_t*)0x20000000 = 0);
  NONFAILING(*(uint32_t*)0x20000004 = 0);
  NONFAILING(*(uint32_t*)0x20000008 = 0x300);
  NONFAILING(*(uint32_t*)0x2000000c = 0x4b0);
  NONFAILING(*(uint32_t*)0x20000010 = 0x10000);
  NONFAILING(*(uint32_t*)0x20000014 = 0);
  NONFAILING(*(uint32_t*)0x20000018 = 4);
  NONFAILING(*(uint32_t*)0x2000001c = 0);
  NONFAILING(*(uint32_t*)0x20000020 = 0);
  NONFAILING(*(uint32_t*)0x20000024 = 0);
  NONFAILING(*(uint32_t*)0x20000028 = 0);
  NONFAILING(*(uint32_t*)0x2000002c = 0);
  NONFAILING(*(uint32_t*)0x20000030 = 0);
  NONFAILING(*(uint32_t*)0x20000034 = 0);
  NONFAILING(*(uint32_t*)0x20000038 = 0);
  NONFAILING(*(uint32_t*)0x2000003c = 0);
  NONFAILING(*(uint32_t*)0x20000040 = 0);
  NONFAILING(*(uint32_t*)0x20000044 = 0);
  NONFAILING(*(uint32_t*)0x20000048 = 0);
  NONFAILING(*(uint32_t*)0x2000004c = 0);
  NONFAILING(*(uint32_t*)0x20000050 = 0);
  NONFAILING(*(uint32_t*)0x20000054 = 0);
  NONFAILING(*(uint32_t*)0x20000058 = 0);
  NONFAILING(*(uint32_t*)0x2000005c = 0);
  NONFAILING(*(uint32_t*)0x20000060 = 0);
  NONFAILING(*(uint32_t*)0x20000064 = 0);
  NONFAILING(*(uint32_t*)0x20000068 = 0);
  NONFAILING(*(uint32_t*)0x2000006c = 0);
  NONFAILING(*(uint32_t*)0x20000070 = 0);
  NONFAILING(*(uint32_t*)0x20000074 = 0);
  NONFAILING(*(uint32_t*)0x20000078 = 0);
  NONFAILING(*(uint32_t*)0x2000007c = 0);
  NONFAILING(*(uint32_t*)0x20000080 = 0);
  NONFAILING(*(uint32_t*)0x20000084 = 0);
  NONFAILING(*(uint32_t*)0x20000088 = 0);
  NONFAILING(*(uint32_t*)0x2000008c = 0);
  NONFAILING(*(uint32_t*)0x20000090 = 0);
  NONFAILING(*(uint32_t*)0x20000094 = 0);
  NONFAILING(*(uint32_t*)0x20000098 = 0);
  NONFAILING(*(uint32_t*)0x2000009c = 0);
  syscall(__NR_ioctl, r[0], 0x4601, 0x20000000ul);
}
int main(void)
{
  syscall(__NR_mmap, 0x1ffff000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul);
  syscall(__NR_mmap, 0x20000000ul, 0x1000000ul, 7ul, 0x32ul, -1, 0ul);
  syscall(__NR_mmap, 0x21000000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul);
  setup_binfmt_misc();
  install_segv_handler();
  do_sandbox_none();
  return 0;
}