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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,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 8117EC072B5 for ; Fri, 24 May 2019 10:36:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5C3E621773 for ; Fri, 24 May 2019 10:36:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390624AbfEXKgq (ORCPT ); Fri, 24 May 2019 06:36:46 -0400 Received: from www262.sakura.ne.jp ([202.181.97.72]:60716 "EHLO www262.sakura.ne.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389448AbfEXKgq (ORCPT ); Fri, 24 May 2019 06:36:46 -0400 Received: from fsav303.sakura.ne.jp (fsav303.sakura.ne.jp [153.120.85.134]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id x4OAZW6N082260; Fri, 24 May 2019 19:35:32 +0900 (JST) (envelope-from penguin-kernel@i-love.sakura.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav303.sakura.ne.jp (F-Secure/fsigk_smtp/530/fsav303.sakura.ne.jp); Fri, 24 May 2019 19:35:32 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/530/fsav303.sakura.ne.jp) Received: from [192.168.1.8] (softbank126012062002.bbtec.net [126.12.62.2]) (authenticated bits=0) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTPSA id x4OAZQQO082192 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NO); Fri, 24 May 2019 19:35:32 +0900 (JST) (envelope-from penguin-kernel@i-love.sakura.ne.jp) Subject: Re: [PATCH] printk: Monitor change of console loglevel. To: Dmitry Vyukov Cc: Andrew Morton , Sergey Senozhatsky , LKML , Petr Mladek , Steven Rostedt , Linus Torvalds References: <1557501546-10263-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp> <20190514091917.GA26804@jagdpanzerIV> <3e2cf31d-25af-e7c3-b308-62f64d650974@i-love.sakura.ne.jp> <4d1a4b51-999b-63c6-5ce3-a704013cecb6@i-love.sakura.ne.jp> From: Tetsuo Handa Message-ID: <68486fcf-325f-fbd3-adb4-14666d477917@i-love.sakura.ne.jp> Date: Fri, 24 May 2019 19:35:28 +0900 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2019/05/24 16:55, Dmitry Vyukov wrote: > On Thu, May 23, 2019 at 11:57 AM Tetsuo Handa > wrote: >> >> Well, the culprit of this problem might be syz_execute_func(). >> >> https://twitter.com/ed_maste/status/1131165065485398016 >> >> Then, blacklisting specific syscalls/arguments might not work. >> We will need to guard specific paths on the kernel side using >> some kernel config option... > > Yes, that's a nasty issue. We could stop running random code, or > setuid into nobody, but then we will lose lots of test coverage... > I think that guarding specific paths on the kernel side is better. TOMOYO already added CONFIG_SECURITY_TOMOYO_INSECURE_BUILTIN_SETTING for avoid emitting WARNING: string and getting more test coverage. There are other codes emitting WARNING: string that confuses syzbot. If we guard critical paths like reboot/poweroff request that will destroy the target VM instance, we can get more test coverage while reducing pointless reports.