//                      uname faker
//                         v1.0a (24 Jul)
//                              by bugghy (bugghy@rootshell.be)

// Kernel module used to fake uname output for 2.4 kernels

// gcc -isystem /lib/modules/`uname -r`/build/include -O2 -DMODULE -D__KERNEL__ -c uname.c
// insmod uname.o

// You can add an -EFAULT return in case the buffer got corrupted (man 2 uname)

// Uses:
//  1. fun
//  2. start lkm programming
//  3. recompile a new kernel without shellusers noticing

#if CONFIG_MODVERSIONS==1 // was it defined in kernel ?
#define MODVERSIONS
#include <linux/modversions.h>
#endif

#include <linux/kernel.h> // we're in kernel mode
#include <linux/module.h> // we code a module
#include <sys/syscall.h> // syscall table
#include <sys/utsname.h> // struct utsname
#include <asm/uaccess.h> // copy_to_user

MODULE_AUTHOR("bugghy");
MODULE_DESCRIPTION("uname faker");
MODULE_LICENSE("Dual BSD/GPL");


#define SYSNAME "Plan9"
#define NODENAME "hellboy"
#define RELEASE "0.0.0"
#define VERSION "#0 Fri Aug 13 13:13:13 PPP 6969"
#define MACHINE "x0w33d"

extern void *sys_call_table[];

int (*o_uname) (struct utsname *buf);

int h_uname(struct utsname *buf){

        int x;
        
        x = o_uname(buf);

#ifdef SYSNAME  
        copy_to_user(buf->sysname, SYSNAME, sizeof buf->sysname);
#endif

#ifdef NODENAME
        copy_to_user(buf->nodename, NODENAME, sizeof buf->nodename);
#endif

#ifdef RELEASE
        copy_to_user(buf->release, RELEASE, sizeof buf->release);
#endif

#ifdef VERSION
        copy_to_user(buf->version, VERSION, sizeof buf->version);
#endif

#ifdef MACHINE
        copy_to_user(buf->machine, MACHINE, sizeof buf->machine);
#endif

        return x;
}

int init_module(void) // replace original uname with hacked one
{
        o_uname = sys_call_table[SYS_uname];
        sys_call_table[SYS_uname] = h_uname;
        return 0;
}

void cleanup_module(void) // replace hacked uname with original one
{
        sys_call_table[SYS_uname] = o_uname;
}