From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753370AbeEGWjP (ORCPT ); Mon, 7 May 2018 18:39:15 -0400 Received: from mx2.suse.de ([195.135.220.15]:47447 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752929AbeEGWjN (ORCPT ); Mon, 7 May 2018 18:39:13 -0400 Date: Mon, 7 May 2018 22:39:10 +0000 From: "Luis R. Rodriguez" To: Waiman Long Cc: "Luis R. Rodriguez" , Kees Cook , Andrew Morton , Jonathan Corbet , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-doc@vger.kernel.org, Al Viro , Matthew Wilcox , "Eric W. Biederman" Subject: Re: [PATCH v7 1/4] ipc: IPCMNI limit check for msgmni and shmmni Message-ID: <20180507223910.GW27853@wotan.suse.de> References: <1525726752-29281-1-git-send-email-longman@redhat.com> <1525726752-29281-2-git-send-email-longman@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1525726752-29281-2-git-send-email-longman@redhat.com> User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 07, 2018 at 04:59:09PM -0400, Waiman Long wrote: > A user can write arbitrary integer values to msgmni and shmmni sysctl > parameters without getting error, but the actual limit is really > IPCMNI (32k). This can mislead users as they think they can get a > value that is not real. > > The right limits are now set for msgmni and shmmni so that the users > will become aware if they set a value outside of the acceptable range. > > Signed-off-by: Waiman Long > --- > ipc/ipc_sysctl.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/ipc/ipc_sysctl.c b/ipc/ipc_sysctl.c > index 8ad93c2..f87cb29 100644 > --- a/ipc/ipc_sysctl.c > +++ b/ipc/ipc_sysctl.c > @@ -99,6 +99,7 @@ static int proc_ipc_auto_msgmni(struct ctl_table *table, int write, > static int zero; > static int one = 1; > static int int_max = INT_MAX; > +static int ipc_mni = IPCMNI; > > static struct ctl_table ipc_kern_table[] = { > { > @@ -120,7 +121,9 @@ static int proc_ipc_auto_msgmni(struct ctl_table *table, int write, > .data = &init_ipc_ns.shm_ctlmni, > .maxlen = sizeof(init_ipc_ns.shm_ctlmni), > .mode = 0644, > - .proc_handler = proc_ipc_dointvec, > + .proc_handler = proc_ipc_dointvec_minmax, > + .extra1 = &zero, > + .extra2 = &ipc_mni, > }, > { > .procname = "shm_rmid_forced", > @@ -147,7 +150,7 @@ static int proc_ipc_auto_msgmni(struct ctl_table *table, int write, > .mode = 0644, > .proc_handler = proc_ipc_dointvec_minmax, > .extra1 = &zero, > - .extra2 = &int_max, > + .extra2 = &ipc_mni, > }, > { > .procname = "auto_msgmni", > -- > 1.8.3.1 It seems negative values are not allowed, if true then having a caller to use proc_douintvec_minmax() would help with ensuring no invalid negative input values are used as well. Luis