// https://syzkaller.appspot.com/bug?id=3c9de7cdda84f5ac72539dc855610c423f3ef9a5
// autogenerated by syzkaller (https://github.com/google/syzkaller)

#define _GNU_SOURCE

#include <endian.h>
#include <errno.h>
#include <fcntl.h>
#include <sched.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 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);
}

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[2] = {0xffffffffffffffff, 0xffffffffffffffff};

void loop(void)
{
  intptr_t res = 0;
  memcpy((void*)0x20000280, "/dev/infiniband/rdma_cm\000", 24);
  res = syscall(__NR_openat, 0xffffffffffffff9c, 0x20000280, 2, 0);
  if (res != -1)
    r[0] = res;
  *(uint32_t*)0x20000080 = 0;
  *(uint16_t*)0x20000084 = 0x18;
  *(uint16_t*)0x20000086 = 0xfa00;
  *(uint64_t*)0x20000088 = 0;
  *(uint64_t*)0x20000090 = 0x20000040;
  *(uint16_t*)0x20000098 = 0x106;
  *(uint8_t*)0x2000009a = 0;
  *(uint8_t*)0x2000009b = 0;
  *(uint8_t*)0x2000009c = 0;
  *(uint8_t*)0x2000009d = 0;
  *(uint8_t*)0x2000009e = 0;
  *(uint8_t*)0x2000009f = 0;
  res = syscall(__NR_write, r[0], 0x20000080, 0x20);
  if (res != -1)
    r[1] = *(uint32_t*)0x20000040;
  *(uint32_t*)0x200002c0 = 0x14;
  *(uint16_t*)0x200002c4 = 0x88;
  *(uint16_t*)0x200002c6 = 0xfa00;
  *(uint32_t*)0x200002c8 = r[1];
  *(uint16_t*)0x200002cc = 0x30;
  *(uint16_t*)0x200002ce = 0;
  *(uint16_t*)0x200002d0 = 0x1b;
  *(uint16_t*)0x200002d2 = htobe16(0);
  *(uint32_t*)0x200002d4 = htobe32(0);
  memcpy((void*)0x200002d8,
         "\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000",
         16);
  *(uint64_t*)0x200002e8 = htobe64(0);
  *(uint64_t*)0x200002f0 = htobe64(-1);
  *(uint64_t*)0x200002f8 = 0;
  syscall(__NR_write, r[0], 0x200002c0, 0x90);
}
int main(void)
{
  syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0);
  setup_binfmt_misc();
  do_sandbox_none();
  return 0;
}