shellcoding on gentoo

[padre <padre () correo ugr es>]

Hi!

Last months I wrote many shellcodes on debian, and they work very well. Now,
I've got gentoo running on my box.
When executing the shellcodes that I wrote in my debian,I gotta "SEG FAULT".
I revised the code and it looks good ! .Guys, do you now why the code crash?

Thanks in advance!

-----------------------------------------------------------------------------
-----------------------------------------------------------------------------
----------- # uname -a
Linux petalo 2.6.12-gentoo-r6 #9 Sat Dec 24 14:37:56 CET 2005 i686 AMD
Athlon(tm) XP 1600+ AuthenticAMD GNU/Linux

# cat 1.asm
BITS 32
xor ecx,ecx
xor edx,edx

; execve("/bin/sh0",{"/bin/sh0",NULL},NULL);
push ecx
push $68732f2f
push $6e69622f
mov ebx,esp

push ecx
push ebx
mov ecx,esp

mov al,0xb
int 0x80

# nasm -f elf 1.asm
#ld 1.o
ld: warning: cannot find entry symbol _start; defaulting to 00000000080480a0
# ./a.out
Segmentation fault

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