From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755301AbdGTQmw (ORCPT ); Thu, 20 Jul 2017 12:42:52 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59578 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754901AbdGTQmv (ORCPT ); Thu, 20 Jul 2017 12:42:51 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 403A6655D Authentication-Results: ext-mx10.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx10.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=oleg@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 403A6655D Date: Thu, 20 Jul 2017 18:42:49 +0200 From: Oleg Nesterov To: Dmitry Safonov , Thomas Gleixner , Andrew Morton Cc: Andy Lutomirski , Borislav Petkov , Cyrill Gorcunov , linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] x86: fix norandmaps Message-ID: <20170720164249.GA14793@redhat.com> References: <20170710111429.GA20038@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170710111429.GA20038@redhat.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Thu, 20 Jul 2017 16:42:51 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ping ;) On 07/10, Oleg Nesterov wrote: > > Documentation/admin-guide/kernel-parameters.txt says: > > norandmaps Don't use address space randomization. Equivalent > to echo 0 > /proc/sys/kernel/randomize_va_space > > but it doesn't work because arch_rnd() which is used to randomize > mm->mmap_base returns a random value unconditionally. > > Shift the PF_RANDOMIZE check from arch_mmap_rnd() to arch_rnd(). > > Fixes: 1b028f784e8c ("x86/mm: Introduce mmap_compat_base() for 32-bit mmap()") > Signed-off-by: Oleg Nesterov > --- > arch/x86/mm/mmap.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/mm/mmap.c b/arch/x86/mm/mmap.c > index 19ad095..6369d04 100644 > --- a/arch/x86/mm/mmap.c > +++ b/arch/x86/mm/mmap.c > @@ -82,13 +82,13 @@ static int mmap_is_legacy(void) > > static unsigned long arch_rnd(unsigned int rndbits) > { > + if (!(current->flags & PF_RANDOMIZE)) > + return 0; > return (get_random_long() & ((1UL << rndbits) - 1)) << PAGE_SHIFT; > } > > unsigned long arch_mmap_rnd(void) > { > - if (!(current->flags & PF_RANDOMIZE)) > - return 0; > return arch_rnd(mmap_is_ia32() ? mmap32_rnd_bits : mmap64_rnd_bits); > } > > -- > 2.5.0 >