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=-0.8 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 B2138ECE566 for ; Thu, 20 Sep 2018 15:21:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 694F821479 for ; Thu, 20 Sep 2018 15:21:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=yahoo.com header.i=@yahoo.com header.b="KSCnF8/V" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 694F821479 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=schaufler-ca.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387481AbeITVE7 (ORCPT ); Thu, 20 Sep 2018 17:04:59 -0400 Received: from sonic304-17.consmr.mail.bf2.yahoo.com ([74.6.128.40]:38586 "EHLO sonic304-17.consmr.mail.bf2.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733258AbeITVE6 (ORCPT ); Thu, 20 Sep 2018 17:04:58 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s2048; t=1537456859; bh=7FjwnZHpf+5P82oFLsLLkybP/C1DyPN/tYcPzqVjLLo=; h=Subject:To:References:From:Date:In-Reply-To:From:Subject; b=KSCnF8/V5HzrpCdyxvrvyPrzLa15LLNegBxc5ciQHhtIPTBHwlISqmmGmYdWrw9nT79q4L4Z7rgigw2mjH56nUSZHssZ7m3kWgeosoBRteqolZfwaik8/Kth3+rv59j3eq+021H8SXcILP2q98wxV56HBZW6FuvTa8IKXWbDdbO8RSp/EierGmPkxd57dzmWXYEhOWnaj1gNqB8Q/Gk1yADic/Lek5mlldq2Ob/PHxFsosbrTNgSmVW0txZ1+AsJTsz8N9suDsFPXhdhRY/kp/FotO4gMiy6NOrH5GX6WGKHhhQdPOqv5P/95a95o4UrxcKJHlCVIPWK5NKvwW2BlA== X-YMail-OSG: WNI.G_kVM1mhbkdN2nufYLjpq0aavoqrqcF1TRlAa2dFeHwJufe2CdBKYjaMHex 3WxWYGl8o_pELjhk8KNyPLVyXED.TXwMEPl_UHDBgbFVvUseiWg.Xy2tysXsGYCK8Oy8bqkMj_KB 0IunEro8AnSEzjexnESR5s7NvXgHvpQpfDgNJ0W5_dv3IaXUhk04USOJSQCyaorOdQFIxd5SjsGO L5rJfjW4pXFYwAYcnjhC4.OImL2fXqob1a6G1o1WCMvIMBYFPQmqhAPlZ8zTRAR3LJ_1beTNhcUU HIncoxiSYHjHVnjgMsTx6aCo4ufY6tes4H_F0rjrYULnDsZPJJM6VkPr7SBZzjjTBmiBCPzoTppV 7XgO3W7OHYWZ6yw4v3K_ZgdSBqtsVoM2ZtyPlvN7xMDFmPc7kZgehknnC03SZpq3DWZl4Q2S5JrM t3qx8lC0sTg5maug_bXFD9vVEWkGw66p53qpwbNyuFe6_R0e9svHrk7ESYgRnwIl9ciUHrFhuWex iLCIodLq5Dxl7RtK52EbD3BW3dCjvLu8DGcvcMpXKBxHawG6Sz3msdfLoTxwenrylw4T1P2F97Nv 6fz3IcLTi8suK8QWXjBuCRK5ny.M4AKProC.KCjCpAUUCBkapkJ23Jx5AKGiFSSpIKEIsR7d77wZ GiwdkI_PSAzFQ5avMoa2Csc645qv0wdGTuHQaxpJVPjj1k1bAjE7UmZlakZVt5CaNYYCRSm3P3pk e4gRvs7xfKj0DRwZz0EibWEXqXZMwSo.LVNPfNGW_HkSmO.mniCFoQMBlxMt6nO09NVtD7GkHoRM UxV8EFui.cMASsZ8J0CD.cg4Bbwo2UjLkXgaW82mCvVo38lXBNb2smPTTDW6r7Dsh1xHluNjXoNp sy.bg8gPWz9qf3VtqdYl_SsWRdXSxObLxUNBalEw3v46388dDjIP79hwMvOE.O6aySFqWtxqPm4c wJEuQ4OODpGqhAqhLqqtZv7paLQBy9qqhPJIK74Ej35HfXMbANy.nNX12861becZquTiExkgKJEn NOFoACydAteamC6bEJX7pEA-- Received: from sonic.gate.mail.ne1.yahoo.com by sonic304.consmr.mail.bf2.yahoo.com with HTTP; Thu, 20 Sep 2018 15:20:59 +0000 Received: from c-67-169-65-224.hsd1.ca.comcast.net (EHLO [192.168.0.102]) ([67.169.65.224]) by smtp423.mail.bf1.yahoo.com (Oath Hermes SMTP Server) with ESMTPA ID 379d111bb48eafd443e6480bbc8e5ea8; Thu, 20 Sep 2018 15:20:55 +0000 (UTC) Subject: Re: [PATCH v3 09/16] SELinux: Abstract use of file security blob To: David Laight , LSM , James Morris , SE Linux , LKLM , John Johansen , Kees Cook , Tetsuo Handa , Paul Moore , Stephen Smalley , "linux-fsdevel@vger.kernel.org" , Alexey Dobriyan , =?UTF-8?Q?Micka=c3=abl_Sala=c3=bcn?= , Salvatore Mesoraca References: <748c61cb-b6fa-c36d-a7b3-2315ff6292af@schaufler-ca.com> <14db9a22-9f31-88fb-dbc1-8bc4ade74bf6@schaufler-ca.com> <124ae3859e8141deb35ed8355370b4ed@AcuMS.aculab.com> From: Casey Schaufler Message-ID: <4db0c110-c1aa-aac8-901f-a9abf662b605@schaufler-ca.com> Date: Thu, 20 Sep 2018 08:20:50 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <124ae3859e8141deb35ed8355370b4ed@AcuMS.aculab.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 9/20/2018 1:51 AM, David Laight wrote: > From: Casey Schaufler >> Sent: 20 September 2018 01:21 >> >> SELinux: Abstract use of file security blob >> >> Don't use the file->f_security pointer directly. >> Provide a helper function that provides the security blob pointer. > ... >> +static inline struct file_security_struct *selinux_file(const struct file *file) >> +{ >> + return file->f_security; >> +} >> + > Why? In patch 16/16 this becomes: static inline struct file_security_struct *selinux_file(const struct file *file) { +#ifdef CONFIG_SECURITY_STACKING + return file->f_security + selinux_blob_sizes.lbs_file; +#else return file->f_security; +#endif } You could hard code this bit everywhere it's used, but that would be prone to error. I'm not generally an abstractionist myself, but it these cases abstraction adds value.