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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 0EDEFC433DF for ; Tue, 30 Jun 2020 23:00:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E833F20780 for ; Tue, 30 Jun 2020 22:59:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726085AbgF3W77 (ORCPT ); Tue, 30 Jun 2020 18:59:59 -0400 Received: from www262.sakura.ne.jp ([202.181.97.72]:51934 "EHLO www262.sakura.ne.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725791AbgF3W77 (ORCPT ); Tue, 30 Jun 2020 18:59:59 -0400 Received: from fsav402.sakura.ne.jp (fsav402.sakura.ne.jp [133.242.250.101]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id 05UMx2ox072030; Wed, 1 Jul 2020 07:59:02 +0900 (JST) (envelope-from penguin-kernel@i-love.sakura.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav402.sakura.ne.jp (F-Secure/fsigk_smtp/550/fsav402.sakura.ne.jp); Wed, 01 Jul 2020 07:59:02 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/fsav402.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 05UMx1ds071983 (version=TLSv1.2 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Wed, 1 Jul 2020 07:59:02 +0900 (JST) (envelope-from penguin-kernel@i-love.sakura.ne.jp) Subject: Re: [PATCH 00/14] Make the user mode driver code a better citizen To: Alexei Starovoitov Cc: "Eric W. Biederman" , Linus Torvalds , David Miller , Greg Kroah-Hartman , Kees Cook , Andrew Morton , Alexei Starovoitov , Al Viro , bpf , linux-fsdevel , Daniel Borkmann , Jakub Kicinski , Masahiro Yamada , Gary Lin , Bruno Meneguele , LSM List , Casey Schaufler References: <20200625.123437.2219826613137938086.davem@davemloft.net> <87pn9mgfc2.fsf_-_@x220.int.ebiederm.org> <40720db5-92f0-4b5b-3d8a-beb78464a57f@i-love.sakura.ne.jp> <87366g8y1e.fsf@x220.int.ebiederm.org> <20200628194440.puzh7nhdnk6i4rqj@ast-mbp.dhcp.thefacebook.com> <874kqt39qo.fsf@x220.int.ebiederm.org> <6a9dd8be-333a-fd21-d125-ec20fb7c81df@i-love.sakura.ne.jp> <20200630164817.txa2jewfvk4stajy@ast-mbp.dhcp.thefacebook.com> From: Tetsuo Handa Message-ID: <12eba0ed-c345-b564-9b99-883615dd89f3@i-love.sakura.ne.jp> Date: Wed, 1 Jul 2020 07:58:59 +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: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: On 2020/07/01 6:57, Alexei Starovoitov wrote: >>>>> They were all should never happen cases. Which is why my patches do: >>>>> if (WARN_ON_ONCE(...)) >>>> >>>> No. Fuzz testing (which uses panic_on_warn=1) will trivially hit them. >>> >>> I don't believe that's true. >>> Please show fuzzing stack trace to prove your point. >>> >> >> Please find links containing "WARNING" from https://syzkaller.appspot.com/upstream . ;-) > > Is it a joke? Do you understand how syzbot works? > If so, please explain how it can invoke umd_* interface. > Currently syzkaller can't invoke umd_* interface because this interface is used by only bpfilter_umh module. But I can imagine that someone starts using this interface in a way syzkaller can somehow invoke. Thus, how can it be a joke? I don't understand your question.