From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Thu, 19 Jul 2007 08:11:04 +0100 (BST) Received: from ug-out-1314.google.com ([66.249.92.174]:13934 "EHLO ug-out-1314.google.com") by ftp.linux-mips.org with ESMTP id S20022459AbXGSHLA (ORCPT ); Thu, 19 Jul 2007 08:11:00 +0100 Received: by ug-out-1314.google.com with SMTP id u2so379634uge for ; Thu, 19 Jul 2007 00:10:59 -0700 (PDT) DKIM-Signature: a=rsa-sha1; c=relaxed/relaxed; d=gmail.com; s=beta; h=domainkey-signature:received:received:message-id:date:reply-to:user-agent:mime-version:to:cc:subject:x-enigmail-version:content-type:content-transfer-encoding:from; b=K9EM4GICseFsafUxisGWTWqFqAv1FdM1KT/oGdFj+FXXYgm5mMzDS3sx/f1msmGjuNEugHIkhvNlExQXy39G/TWthhmOGwKlP37TwQH09Mfk3h16FM0UGppmVbPqReWiKgQl4HnYjgQZPhHARnig6caCDP96yoPQbp2jMeWG6QI= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:reply-to:user-agent:mime-version:to:cc:subject:x-enigmail-version:content-type:content-transfer-encoding:from; b=bh5+8AnSd4brf1EVLnDi5nbGRa9RJe5wYXlvFMn/WWpKOyCcbx2v3MpD5WzVXmQVka/U2C7rdXMQBwNK2zIAML/XwMkoOgsQ5oUNNxFGcmO5Ps60DrkDqS1+tpEMotVGNmvOd3Lu5WWQ0Bk7gzLBTQRZGXQey1rmGXdbdl0sge4= Received: by 10.86.86.12 with SMTP id j12mr1712949fgb.1184829059796; Thu, 19 Jul 2007 00:10:59 -0700 (PDT) Received: from ?192.168.0.24? ( [81.252.61.1]) by mx.google.com with ESMTPS id b17sm3718620fka.2007.07.19.00.10.58 (version=TLSv1/SSLv3 cipher=RC4-MD5); Thu, 19 Jul 2007 00:10:58 -0700 (PDT) Message-ID: <469F0E5F.4050005@innova-card.com> Date: Thu, 19 Jul 2007 09:10:23 +0200 Reply-To: Franck User-Agent: Thunderbird 1.5.0.4 (X11/20060614) MIME-Version: 1.0 To: Ralf Baechle CC: linux-mips Subject: [RFC] User stack pointer randomisation X-Enigmail-Version: 0.94.4.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit From: Franck Bui-Huu Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 15801 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: vagabon.xyz@gmail.com Precedence: bulk X-list: linux-mips This patch adds a page size range randomisation to the user stack pointer. Signed-off-by: Franck Bui-Huu --- Hi Ralf, This is taken from the x86 architecture. I modified it a bit so the randomisation range is only a page size range. Since the top of the stack is already randomised, I don't see any point to make the range bigger as this is the case in x86 arch. I'm surely missing something obvious and that's the reason this patch is a RFC. I tested it and it works fine so far. Please try to have a look, Franck arch/mips/kernel/process.c | 13 +++++++++++++ include/asm-mips/system.h | 2 +- 2 files changed, 14 insertions(+), 1 deletions(-) diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c index 6bdfb5a..4f411fa 100644 --- a/arch/mips/kernel/process.c +++ b/arch/mips/kernel/process.c @@ -25,6 +25,7 @@ #include #include #include +#include #include #include @@ -460,3 +461,15 @@ unsigned long get_wchan(struct task_struct *task) out: return pc; } + +/* + * Don't forget that the stack pointer must be aligned on a 8 bytes + * boundary at least. + */ +unsigned long arch_align_stack(unsigned long sp) +{ + if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) + sp -= get_random_int() & ~PAGE_MASK; + + return sp & ~7; +} diff --git a/include/asm-mips/system.h b/include/asm-mips/system.h index 2908870..0cfb6e1 100644 --- a/include/asm-mips/system.h +++ b/include/asm-mips/system.h @@ -355,6 +355,6 @@ extern int stop_a_enabled; */ #define __ARCH_WANT_UNLOCKED_CTXSW -#define arch_align_stack(x) (x) +extern unsigned long arch_align_stack(unsigned long sp); #endif /* _ASM_SYSTEM_H */ -- 1.5.2.2