From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AEFF3C2BA12 for ; Thu, 2 Apr 2020 16:08:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8FDE52063A for ; Thu, 2 Apr 2020 16:08:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389723AbgDBQIX (ORCPT ); Thu, 2 Apr 2020 12:08:23 -0400 Received: from out03.mta.xmission.com ([166.70.13.233]:35208 "EHLO out03.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389392AbgDBQIW (ORCPT ); Thu, 2 Apr 2020 12:08:22 -0400 Received: from in02.mta.xmission.com ([166.70.13.52]) by out03.mta.xmission.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1jK2OD-0007Me-0v; Thu, 02 Apr 2020 10:08:21 -0600 Received: from ip68-227-160-95.om.om.cox.net ([68.227.160.95] helo=x220.xmission.com) by in02.mta.xmission.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.87) (envelope-from ) id 1jK2Nx-00044C-IX; Thu, 02 Apr 2020 10:08:20 -0600 From: ebiederm@xmission.com (Eric W. Biederman) To: Alexey Gladkov Cc: LKML , Kernel Hardening , Linux API , Linux FS Devel , Linux Security Module , Akinobu Mita , Alexander Viro , Alexey Dobriyan , Alexey Gladkov , Andrew Morton , Andy Lutomirski , Daniel Micay , Djalal Harouni , "Dmitry V . Levin" , Greg Kroah-Hartman , Ingo Molnar , "J . Bruce Fields" , Jeff Layton , Jonathan Corbet , Kees Cook , Linus Torvalds , Oleg Nesterov , David Howells References: <20200327172331.418878-1-gladkov.alexey@gmail.com> <20200327172331.418878-9-gladkov.alexey@gmail.com> Date: Thu, 02 Apr 2020 11:05:21 -0500 In-Reply-To: <20200327172331.418878-9-gladkov.alexey@gmail.com> (Alexey Gladkov's message of "Fri, 27 Mar 2020 18:23:30 +0100") Message-ID: <87d08pkh4u.fsf@x220.int.ebiederm.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=1jK2Nx-00044C-IX;;;mid=<87d08pkh4u.fsf@x220.int.ebiederm.org>;;;hst=in02.mta.xmission.com;;;ip=68.227.160.95;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX19Wu6fmQHfDofF39L0DBA9uLm55GXDDZi0= X-SA-Exim-Connect-IP: 68.227.160.95 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: Re: [PATCH v10 8/9] proc: use human-readable values for hidehid X-SA-Exim-Version: 4.2.1 (built Thu, 05 May 2016 13:38:54 -0600) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Sender: linux-api-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-api@vger.kernel.org Alexey Gladkov writes: > The hidepid parameter values are becoming more and more and it becomes > difficult to remember what each new magic number means. In principle I like this change. In practice I think you have just broken ABI compatiblity with the new mount ABI. In particular the following line seems broken. > diff --git a/fs/proc/root.c b/fs/proc/root.c > index dbcd96f07c7a..ba782d6e6197 100644 > --- a/fs/proc/root.c > +++ b/fs/proc/root.c > @@ -45,7 +45,7 @@ enum proc_param { > > static const struct fs_parameter_spec proc_fs_parameters[] = { > fsparam_u32("gid", Opt_gid), > - fsparam_u32("hidepid", Opt_hidepid), > + fsparam_string("hidepid", Opt_hidepid), > fsparam_string("subset", Opt_subset), > {} > }; As I read fs_parser.c fs_param_is_u32 handles string inputs and turns them into numbers, and it handles binary numbers. However fs_param_is_string appears to only handle strings. It appears to have not capacity to turn raw binary numbers into strings. So I think we probably need to fix fs_param_is_string to raw binary numbers before we can safely make this change to fs/proc/root.c David am I reading the fs_parser.c code correctly? If I am are you ok with a change like the above? Eric