Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757086AbXH1NRk (ORCPT ); Tue, 28 Aug 2007 09:17:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753613AbXH1NRc (ORCPT ); Tue, 28 Aug 2007 09:17:32 -0400 Received: from fk-out-0910.google.com ([209.85.128.190]:24885 "EHLO fk-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753598AbXH1NRc (ORCPT ); Tue, 28 Aug 2007 09:17:32 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:user-agent:mime-version:to:cc:subject:references:in-reply-to:content-type:content-transfer-encoding; b=gzhfmFqRY2j5JUkhdq4FEVshTYZU/so3ujuSUWQxy8tdNJf/e3B1BGLxNLCpC+mjhgbhS6jKvWb8VFYmjSPemOy8ZzpYnqbYjb3++Yo/lE6XoS8bTaw1faa0FdRhvz3DUbxdnYSJf6xAxJ21GMfD+jc2v7ZFrbEyTppG+Y7xoyE= Message-ID: <46D42057.9090507@gmail.com> Date: Tue, 28 Aug 2007 15:17:11 +0200 From: Franck Bui-Huu User-Agent: Thunderbird 2.0.0.5 (X11/20070719) MIME-Version: 1.0 To: Arjan van de Ven CC: Linux Kernel Mailing List Subject: Re: arch_align_stack() seems useless References: <46D2DADF.8060505@gmail.com> <20070827071413.736e3dcb@laptopd505.fenrus.org> In-Reply-To: <20070827071413.736e3dcb@laptopd505.fenrus.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1269 Lines: 37 Hello Arjan, Arjan van de Ven wrote: > arch_align_stack aligns, on x86, within a 2 page range (this is for > cache coloring). OK, but for elf case this seems useless since the top of the stack is already randomized. It seems that the randomization stuff (top of the stack + stack pointer inside a page) belongs to the elf binary format whereas it could have been part of exec.c. Are there any reasons ? > The other thing you missed is that arch_align_stack() > is called in 2 locations, binfmt_elf.c is the primary location for > inside-the-page randomization. > Well not really because for mips case, we have: $ git grep ELF_PLATFORM include/asm-mips include/asm-mips/elf.h:#define ELF_PLATFORM (NULL) So on mips, the stack pointer won't get the inside the page randomization. Is that correct ? If so, I'm wondering why this randomization must depend on that string to be defined. I must admit that I'm not sure how it's used. I guess it's used by ld.so and it could be set to "mips" for now... thanks Franck - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/