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=-5.2 required=3.0 tests=BAYES_00, 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 07B91C433E0 for ; Thu, 4 Feb 2021 20:49:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ABA3864F5E for ; Thu, 4 Feb 2021 20:49:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229774AbhBDUte (ORCPT ); Thu, 4 Feb 2021 15:49:34 -0500 Received: from jabberwock.ucw.cz ([46.255.230.98]:57822 "EHLO jabberwock.ucw.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229702AbhBDUtd (ORCPT ); Thu, 4 Feb 2021 15:49:33 -0500 Received: by jabberwock.ucw.cz (Postfix, from userid 1017) id 782BA1C0B77; Thu, 4 Feb 2021 21:48:36 +0100 (CET) Date: Thu, 4 Feb 2021 21:48:35 +0100 From: Pavel Machek To: Timur Tabi Cc: Petr Mladek , Steven Rostedt , Sergey Senozhatsky , linux-kernel@vger.kernel.org, linux-mm@kvack.org, willy@infradead.org, akpm@linux-foundation.org, torvalds@linux-foundation.org, roman.fietze@magna.com, keescook@chromium.org, john.ogness@linutronix.de, akinobu.mita@gmail.com Subject: Re: [PATCH] lib/vsprintf: make-printk-non-secret printks all addresses as unhashed Message-ID: <20210204204835.GA7529@amd> References: <20210202201846.716915-1-timur@kernel.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="1yeeQ81UyVL57Vl7" Content-Disposition: inline In-Reply-To: <20210202201846.716915-1-timur@kernel.org> User-Agent: Mutt/1.5.23 (2014-03-12) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --1yeeQ81UyVL57Vl7 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue 2021-02-02 14:18:46, Timur Tabi wrote: > If the make-printk-non-secret command-line parameter is set, then > printk("%p") will print addresses as unhashed. This is useful for > debugging purposes. >=20 > A large warning message is displayed if this option is enabled, > because unhashed addresses, while useful for debugging, exposes > kernel addresses which can be a security risk. Yes please. I needed to see pointers for debugging, and seeing hashed pointers is nasty. Having to patch C code to be able to develop... is bad. > + pr_warn("** Kernel memory addresses are exposed, which may **\n"); > + pr_warn("** compromise security on your system. **\n"); This is lies, right? And way too verbose. Pavel --=20 http://www.livejournal.com/~pavelmachek --1yeeQ81UyVL57Vl7 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAmAcXaMACgkQMOfwapXb+vKvOQCeNeIzhzv70yiBaBw63hsqyL7n Bm0An3ALaR2Z9WS8hhX/DU42VPs9cxmx =lE4c -----END PGP SIGNATURE----- --1yeeQ81UyVL57Vl7--