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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 07B9EC433DF for ; Tue, 9 Jun 2020 05:30:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D7372207ED for ; Tue, 9 Jun 2020 05:30:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728027AbgFIFaF (ORCPT ); Tue, 9 Jun 2020 01:30:05 -0400 Received: from www262.sakura.ne.jp ([202.181.97.72]:65353 "EHLO www262.sakura.ne.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727824AbgFIFaF (ORCPT ); Tue, 9 Jun 2020 01:30:05 -0400 Received: from fsav405.sakura.ne.jp (fsav405.sakura.ne.jp [133.242.250.104]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id 0595TCte076702; Tue, 9 Jun 2020 14:29:12 +0900 (JST) (envelope-from penguin-kernel@i-love.sakura.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav405.sakura.ne.jp (F-Secure/fsigk_smtp/550/fsav405.sakura.ne.jp); Tue, 09 Jun 2020 14:29:12 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/fsav405.sakura.ne.jp) Received: from [192.168.1.9] (M106072142033.v4.enabler.ne.jp [106.72.142.33]) (authenticated bits=0) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTPSA id 0595TAji076692 (version=TLSv1.2 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Tue, 9 Jun 2020 14:29:12 +0900 (JST) (envelope-from penguin-kernel@i-love.sakura.ne.jp) Subject: Re: [RFC][PATCH] net/bpfilter: Remove this broken and apparently unmantained To: Alexei Starovoitov Cc: Linus Torvalds , "Eric W. Biederman" , Kees Cook , Andrew Morton , Alexei Starovoitov , David Miller , Al Viro , bpf , linux-fsdevel , Daniel Borkmann , Jakub Kicinski , Masahiro Yamada , Gary Lin , Bruno Meneguele References: <20200329005528.xeKtdz2A0%akpm@linux-foundation.org> <13fb3ab7-9ab1-b25f-52f2-40a6ca5655e1@i-love.sakura.ne.jp> <202006051903.C44988B@keescook> <875zc4c86z.fsf_-_@x220.int.ebiederm.org> <20200606201956.rvfanoqkevjcptfl@ast-mbp> <20200607014935.vhd3scr4qmawq7no@ast-mbp> <33cf7a57-0afa-9bb9-f831-61cca6c19eba@i-love.sakura.ne.jp> <20200608162306.iu35p4xoa2kcp3bu@ast-mbp.dhcp.thefacebook.com> <20200609012826.dssh2lbfr6tlhwwa@ast-mbp.dhcp.thefacebook.com> From: Tetsuo Handa Message-ID: Date: Tue, 9 Jun 2020 14:29:09 +0900 User-Agent: Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.9.0 MIME-Version: 1.0 In-Reply-To: <20200609012826.dssh2lbfr6tlhwwa@ast-mbp.dhcp.thefacebook.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On 2020/06/09 10:28, Alexei Starovoitov wrote: >> TOMOYO LSM module uses call_usermodehelper() from tomoyo_load_policy() in order to >> load and apply security policy. What is so nice with fork_usermode_blob() compared >> to existing call_usermodehelper(), at the cost of confusing LSM modules by allowing >> file-less execve() request from fork_usermode_blob() ? > > For the same reason you did commit 0e4ae0e0dec6 ("TOMOYO: Make several options configurable.") > Quoting your words from that commit: > "To be able to start using enforcing mode from the early stage of boot sequence, > this patch adds support for activating access control without calling external > policy loader program." > I can't catch what you mean. That commit is to allow not to call usermode helper. You can't start a usermode helper which requires access to filesystems (e.g. ELF loaders, shared libraries) before call_usermodehelper() can start a usermode helper which requires access to filesystems. Under such a restricted condition, what is nice with starting a usermode helper? Programs which can be started under such condition will be quite limited. My question is: why you can't use existing call_usermodehelper() (if you need to call a usermode helper) ?