syzkaller-repros/linux/09ac22acb16e0918058be5feeb390921f3897615.c

// KMSAN: uninit-value in tun_get_user
// https://syzkaller.appspot.com/bug?id=09ac22acb16e0918058be5feeb390921f3897615
// status:invalid
// autogenerated by syzkaller (http://github.com/google/syzkaller)

#define _GNU_SOURCE
#include <endian.h>
#include <fcntl.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <unistd.h>

static uintptr_t syz_open_dev(uintptr_t a0, uintptr_t a1, uintptr_t a2)
{
  if (a0 == 0xc || a0 == 0xb) {
    char buf[128];
    sprintf(buf, "/dev/%s/%d:%d", a0 == 0xc ? "char" : "block", (uint8_t)a1,
            (uint8_t)a2);
    return open(buf, O_RDWR, 0);
  } else {
    char buf[1024];
    char* hash;
    strncpy(buf, (char*)a0, sizeof(buf));
    buf[sizeof(buf) - 1] = 0;
    while ((hash = strchr(buf, '#'))) {
      *hash = '0' + (char)(a1 % 10);
      a1 /= 10;
    }
    return open(buf, a2, 0);
  }
}

#ifndef __NR_memfd_create
#define __NR_memfd_create 319
#endif

uint64_t r[3] = {0xffffffffffffffff, 0xffffffffffffffff, 0xffffffffffffffff};
void loop()
{
  long res = 0;
  res = syscall(__NR_socket, 0x11, 0x100000802, 0);
  if (res != -1)
    r[0] = res;
  memcpy((void*)0x20000140, "/dev/net/tun", 13);
  res = syz_open_dev(0x20000140, 0, 0x801);
  if (res != -1)
    r[1] = res;
  memcpy((void*)0x20000040,
         "\x69\x66\x62\x30\x00\xfa\xff\xff\xff\xff\xff\xff\xff\x00\x00\x00",
         16);
  *(uint16_t*)0x20000050 = 0x4002;
  syscall(__NR_ioctl, r[1], 0x400454ca, 0x20000040);
  memcpy((void*)0x20000180,
         "\x69\x66\x62\x30\x00\x00\x91\x78\x5a\x1e\x7a\x27\x5f\xa5\x00\x00",
         16);
  *(uint16_t*)0x20000190 = 0x1301;
  syscall(__NR_ioctl, r[0], 0x8914, 0x20000180);
  memcpy((void*)0x20f0c000, "$", 2);
  res = syscall(__NR_memfd_create, 0x20f0c000, 0);
  if (res != -1)
    r[2] = res;
  syscall(__NR_fallocate, r[2], 0, 3, 0x10001);
  *(uint64_t*)0x20000080 = 0;
  syscall(__NR_sendfile, r[1], r[2], 0x20000080, 0x1000fed);
}

int main()
{
  syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0);
  loop();
  return 0;
}