From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752551AbdHPSkS (ORCPT ); Wed, 16 Aug 2017 14:40:18 -0400 Received: from terminus.zytor.com ([65.50.211.136]:48131 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751635AbdHPSkR (ORCPT ); Wed, 16 Aug 2017 14:40:17 -0400 Date: Wed, 16 Aug 2017 11:36:49 -0700 From: tip-bot for Oleg Nesterov Message-ID: Cc: linux-kernel@vger.kernel.org, kirill.shutemov@linux.intel.com, hpa@zytor.com, oleg@redhat.com, tglx@linutronix.de, akpm@linux-foundation.org, gorcunov@openvz.org, luto@amacapital.net, torvalds@linux-foundation.org, mingo@kernel.org, bp@suse.de, dsafonov@virtuozzo.com Reply-To: oleg@redhat.com, tglx@linutronix.de, hpa@zytor.com, kirill.shutemov@linux.intel.com, linux-kernel@vger.kernel.org, bp@suse.de, dsafonov@virtuozzo.com, mingo@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, luto@amacapital.net, gorcunov@openvz.org In-Reply-To: <20170815153952.GA1076@redhat.com> References: <20170815153952.GA1076@redhat.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/urgent] x86: Fix norandmaps/ADDR_NO_RANDOMIZE Git-Commit-ID: 47ac5484fd961420e5ec0bb5b972fde381f57365 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 47ac5484fd961420e5ec0bb5b972fde381f57365 Gitweb: http://git.kernel.org/tip/47ac5484fd961420e5ec0bb5b972fde381f57365 Author: Oleg Nesterov AuthorDate: Tue, 15 Aug 2017 17:39:52 +0200 Committer: Thomas Gleixner CommitDate: Wed, 16 Aug 2017 20:32:01 +0200 x86: Fix norandmaps/ADDR_NO_RANDOMIZE 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. And as Kirill pointed out, ADDR_NO_RANDOMIZE is broken by the same reason. Just 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 Signed-off-by: Thomas Gleixner Acked-by: Kirill A. Shutemov Acked-by: Cyrill Gorcunov Reviewed-by: Dmitry Safonov Cc: stable@vger.kernel.org Cc: Andy Lutomirski Cc: Andrew Morton Cc: Borislav Petkov Cc: Linus Torvalds Link: http://lkml.kernel.org/r/20170815153952.GA1076@redhat.com --- 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 229d04a..c94df12 100644 --- a/arch/x86/mm/mmap.c +++ b/arch/x86/mm/mmap.c @@ -79,13 +79,13 @@ 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); }