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=0.3 required=3.0 tests=DATE_IN_PAST_03_06, DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, 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 7EF0BC43603 for ; Fri, 13 Dec 2019 21:48:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 38C042253D for ; Fri, 13 Dec 2019 21:48:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576273732; bh=sPWhOOOWVc7e+qdedT6apM7CUC44x6CZqrxWfXP/3wQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=zEVhuaBLWvxSc3mhmx2jaxgZmp7Pcud+fNj8nTug78NsDP/GbP5ZdfyoEhP+8K4HE LJ0hliFpJVYP7GNAj3FNzPb7wBcFsoHvR0KT6NxhxCms16qNn6dMBE+3R51gdRMbQA Q2jbl+uWlSV5xO5GoLcaC78n55IEepNhJH1rcaGs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726808AbfLMVsv (ORCPT ); Fri, 13 Dec 2019 16:48:51 -0500 Received: from mail.kernel.org ([198.145.29.99]:52568 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725554AbfLMVst (ORCPT ); Fri, 13 Dec 2019 16:48:49 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7B9212253D; Fri, 13 Dec 2019 21:48:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576273729; bh=sPWhOOOWVc7e+qdedT6apM7CUC44x6CZqrxWfXP/3wQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Ax2wcx33lygU+VgX2SvejstqfOgJ3u752qTJuWdGb9PRpZJ8N4Of7zfSPql1iBtXE lz32npd0//v5l6YV5Bw81HGnwbdQvOsmOBm1UOFObAfVDryH0ehwEykXVvrGW6ONFm wrljTJyTK9qwOMpxO0d74dj4SrusBBm/m41rEFjY= Date: Fri, 13 Dec 2019 17:07:00 +0100 From: Greg KH To: Tetsuo Handa Cc: Dmitry Vyukov , Linus Torvalds , syzbot , Andy Shevchenko , asierra@xes-inc.com, ext-kimmo.rautkoski@vaisala.com, Jiri Slaby , kai heng feng , LKML , linux-serial , mika.westerberg@linux.intel.com, o.barta89@gmail.com, paulburton@kernel.org, sr@denx.de, syzkaller-bugs , yegorslists@googlemail.com Subject: Re: BUG: unable to handle kernel NULL pointer dereference in mem_serial_out Message-ID: <20191213160700.GA2632926@kroah.com> References: <00000000000053539a0599173973@google.com> <20191212105701.GB1476206@kroah.com> <20191213093357.GB2135612@kroah.com> <74859736-478a-6ad7-f0be-cfe87ec40ff5@i-love.sakura.ne.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <74859736-478a-6ad7-f0be-cfe87ec40ff5@i-love.sakura.ne.jp> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Dec 13, 2019 at 11:31:08PM +0900, Tetsuo Handa wrote: > On 2019/12/13 19:00, Dmitry Vyukov wrote: > > Easier said than done. "normal user of the serial port" is not really > > a thing in Linux, right? You either have CAP_SYS_ADMIN or not, that's > > not per-device... > > As far as I remember +Tetsuo proposed a config along the lines of > > "restrict only things that legitimately cause damage under a fuzzer > > workload", e.g. freezing filesystems, disabling console output, etc. > > This may be another candidate. But I can't find where that proposal is > > now. > > That suggestion got no response for two months. > > https://lkml.kernel.org/r/3e4e2b6b-7828-54ab-cf28-db1a396d7e20@i-love.sakura.ne.jp > > Unless we add such kernel config option to upstream kernels, it will become > a whack-a-mole game. It will be a whack-a-mole game no matter what. Yes, /dev/mem/ makes no sense to fuzz. Neither does other things (like serial port memory addresses.) You just will have a list of things that you "do not fuzz as these are dangerous". Nothing new here, any os will have that. thanks, greg k-h