Vulnerability Development mailing list archives
Re: shellcoding on gentoo
From: DJ Ether <hostmaster () ethericmist net>
Date: Tue, 21 Feb 2006 14:30:29 -0500
Try "mov al,1" instead of "mov eax,1". You'll save 2 bytes and shave off null opcodes if you plan to inject it into a char buffer.
_e Borja wrote:
HiLot of ppl tell me that I did not proper zero the EAX register,so 3 MSB of eax corrupt trapping the syscall, but Its OK. I successfully run the shellcodes on a debian box,but in gentoo,allways SEGFAULT.There is it, a new log:------------------------------------------------------------------------------------------------------------------------------------------------------petalo shellcode # cat 1.asm BITS 32 ;exit() xor eax,eax xor ebx,ebx mov eax,1 int 0x80 petalo shellcode # nasm -g -f elf 1.asm petalo shellcode # ld 1.old: warning: cannot find entry symbol _start; defaulting to 00000000080480a0petalo shellcode # ./a.out Segmentation fault petalo shellcode # gdb -q a.out Using host libthread_db library "/lib/libthread_db.so.1". (gdb) break 1 Breakpoint 1 at 0x80480a0: file 1.asm, line 1. (gdb) r Starting program: /root/code/shellcode/a.out Program terminated with signal SIGSEGV, Segmentation fault. The program no longer exists. You can't do that without a process to debug. (gdb) q petalo shellcode #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------------------------------------------------------------------------------------------------------------------------------------------------------I cant explain why SIGFAULT.I did not edit any advanced kernel configurations rather than snd card and ethernet.Thanks in advance.
Current thread:
- Re: shellcoding on gentoo apriori (Feb 01)
- <Possible follow-ups>
- Re: shellcoding on gentoo nonexistent (Feb 07)
- Re: shellcoding on gentoo Borja (Feb 21)
- Re: shellcoding on gentoo Mike Davis (Feb 21)
- Re: shellcoding on gentoo DJ Ether (Feb 21)
- Re: shellcoding on gentoo Mike Davis (Feb 21)
- Re: shellcoding on gentoo security (Feb 22)