From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754855AbaDSLoE (ORCPT ); Sat, 19 Apr 2014 07:44:04 -0400 Received: from mail-ee0-f48.google.com ([74.125.83.48]:60713 "EHLO mail-ee0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754209AbaDSLoA (ORCPT ); Sat, 19 Apr 2014 07:44:00 -0400 From: Manfred Spraul To: Davidlohr Bueso , Michael Kerrisk , Martin Schwidefsky Cc: LKML , Andrew Morton , KAMEZAWA Hiroyuki , KOSAKI Motohiro , gthelen@google.com, aswin@hp.com, linux-mm@kvack.org, Manfred Spraul Subject: [PATCH 2/4] ipc/shm.c: check for overflows of shm_tot Date: Sat, 19 Apr 2014 13:43:39 +0200 Message-Id: <1397907821-29319-3-git-send-email-manfred@colorfullife.com> X-Mailer: git-send-email 1.9.0 In-Reply-To: <1397907821-29319-2-git-send-email-manfred@colorfullife.com> References: <1397907821-29319-1-git-send-email-manfred@colorfullife.com> <1397907821-29319-2-git-send-email-manfred@colorfullife.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org shm_tot counts the total number of pages used by shm segments. If SHMALL is ULONG_MAX (or nearly ULONG_MAX), then the number can overflow. Subsequent calls to shmctl(,SHM_INFO,) would return wrong values for shm_tot. The patch adds a detection for overflows. Signed-off-by: Manfred Spraul --- ipc/shm.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/ipc/shm.c b/ipc/shm.c index 382e2fb..2dfa3d6 100644 --- a/ipc/shm.c +++ b/ipc/shm.c @@ -493,7 +493,8 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params) if (size < SHMMIN || size > ns->shm_ctlmax) return -EINVAL; - if (ns->shm_tot + numpages > ns->shm_ctlall) + if (ns->shm_tot + numpages < ns->shm_tot || + ns->shm_tot + numpages > ns->shm_ctlall) return -ENOSPC; shp = ipc_rcu_alloc(sizeof(*shp)); -- 1.9.0