From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756015AbeCHTC7 (ORCPT ); Thu, 8 Mar 2018 14:02:59 -0500 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:56476 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754558AbeCHTC6 (ORCPT ); Thu, 8 Mar 2018 14:02:58 -0500 Subject: Re: [PATCH v3 0/6] ipc: Clamp *mni to the real IPCMNI limit To: "Luis R. Rodriguez" Cc: Kees Cook , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Andrew Morton , Al Viro , Matthew Wilcox References: <1519926220-7453-1-git-send-email-longman@redhat.com> <20180308182335.GH4449@wotan.suse.de> From: Waiman Long Organization: Red Hat Message-ID: <90323260-02ee-b7b8-5de3-79378fc972a6@redhat.com> Date: Thu, 8 Mar 2018 14:02:54 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.0 MIME-Version: 1.0 In-Reply-To: <20180308182335.GH4449@wotan.suse.de> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/08/2018 01:23 PM, Luis R. Rodriguez wrote: > On Thu, Mar 01, 2018 at 12:43:34PM -0500, Waiman Long wrote: >> v2->v3: >> - Fix kdoc comment errors. >> - Incorporate comments and suggestions from Luis R. Rodriguez. >> - Add a patch to fix a typo error in fs/proc/proc_sysctl.c. >> >> v1->v2: >> - Add kdoc comments to the do_proc_do{u}intvec_minmax_conv_param >> structures. >> - Add a new flags field to the ctl_table structure for specifying >> whether range clamping should be activated instead of adding new >> sysctl parameter handlers. >> - Clamp the semmni value embedded in the multi-values sem parameter. >> >> v1 patch: https://lkml.org/lkml/2018/2/19/453 >> v2 patch: https://lkml.org/lkml/2018/2/27/627 >> >> The sysctl parameters msgmni, shmmni and semmni have an inherent limit >> of IPC_MNI (32k). However, users may not be aware of that because they >> can write a value much higher than that without getting any error or >> notification. Reading the parameters back will show the newly written >> values which are not real. >> >> Enforcing the limit by failing sysctl parameter write, however, can >> break existing user applications. To address this delemma, a new flags >> field is introduced into the ctl_table. The value CTL_FLAGS_CLAMP_RANGE >> can be added to any ctl_table entries to enable a looser range clamping >> without returning any error. For example, >> >> .flags = CTL_FLAGS_CLAMP_RANGE, >> >> This flags value are now used for the range checking of shmmni, >> msgmni and semmni without breaking existing applications. If any out >> of range value is written to those sysctl parameters, the following >> warning will be printed instead. >> >> Kernel parameter "shmmni" was set out of range [0, 32768], clamped to 32768. >> >> Reading the values back will show 32768 instead of some fake values. > I don't see any addition of respective tests cases, I thought I asked > for this. Please add respective tests cases for all the API you are > adding on lib/test_sysctl.c and respective tests on > tools/testing/selftests/sysctl/sysctl.sh > > Luis I probably missed that. I will add a test case in the next version. -Longman