From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754623AbdJINHM (ORCPT ); Mon, 9 Oct 2017 09:07:12 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:42108 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754306AbdJIMpB (ORCPT ); Mon, 9 Oct 2017 08:45:01 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "=?UTF-8?Q?J=C3=B6rn=20?=Engel" , "Helge Deller" , "Linus Torvalds" , "Oleg Nesterov" , "Hugh Dickins" Date: Mon, 09 Oct 2017 13:44:24 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 116/192] mm: fix overflow check in expand_upwards() In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.49-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Helge Deller commit 37511fb5c91db93d8bd6e3f52f86e5a7ff7cfcdf upstream. Jörn Engel noticed that the expand_upwards() function might not return -ENOMEM in case the requested address is (unsigned long)-PAGE_SIZE and if the architecture didn't defined TASK_SIZE as multiple of PAGE_SIZE. Affected architectures are arm, frv, m68k, blackfin, h8300 and xtensa which all define TASK_SIZE as 0xffffffff, but since none of those have an upwards-growing stack we currently have no actual issue. Nevertheless let's fix this just in case any of the architectures with an upward-growing stack (currently parisc, metag and partly ia64) define TASK_SIZE similar. Link: http://lkml.kernel.org/r/20170702192452.GA11868@p100.box Fixes: bd726c90b6b8 ("Allow stack to grow up to address space limit") Signed-off-by: Helge Deller Reported-by: Jörn Engel Cc: Hugh Dickins Cc: Oleg Nesterov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings --- mm/mmap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2141,7 +2141,7 @@ int expand_upwards(struct vm_area_struct /* Guard against exceeding limits of the address space. */ address &= PAGE_MASK; - if (address >= TASK_SIZE) + if (address >= (TASK_SIZE & PAGE_MASK)) return -ENOMEM; address += PAGE_SIZE;