Received: by 10.223.176.5 with SMTP id f5csp2725455wra; Mon, 5 Feb 2018 08:51:22 -0800 (PST) X-Google-Smtp-Source: AH8x227gw/tnWcSv+O7EliDlKWQl+SE/QAQmndbteL/Zu6YOJBgHULNx3Cf41v3FLkBx1NQYtSEl X-Received: by 2002:a17:902:d24:: with SMTP id 33-v6mr44061153plu.40.1517849482334; Mon, 05 Feb 2018 08:51:22 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1517849482; cv=none; d=google.com; s=arc-20160816; b=Tp9bq6OHygteD+SD/XEnfujDWQNG19ya3xkT7G1akJQhcxulNudWLtP8UEzSon2v+6 EqJjOmWm9AboYbQajTDF6KzZhS8wvrieNIW/MikOFmHgP+YLdrdMbD6cEQJxWOCwE/SH mc+zuSVBehvP/xZVTWabu6TwWhzCBuifWRmZcdM3Outg4VOhzVgXZOrNQfJCwpbeoSoy 7sX6ANlRZkSUF73rQQ+/clv4Ojpi3JqhE1sWAWbesk9PyGC0WASv95FC7bJCOrK+/BVX L3TP6uu5Lmj1/oGR0s8GrCGZEjxRRZZwwlcvttskKXabdkI97fUWZ9pDU0iQKFno6Fbk DjQg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding:mime-version :references:in-reply-to:message-id:subject:cc:to:from:date :dmarc-filter:arc-authentication-results; bh=9MqGp9SBMJRReRtj3zdLSUDrH0oh87LllaoeTI176Nw=; b=z4yj8qKXQzV7t3E0YqYzLy54Dsy+FoV1JRIbnbZd4SD/HZUjSazbewrVq8fiXV84Me IJT+2mjjixrq/bTuKzZKzgWy+hhP9XLNt9T0PgEzQO2vC0F70T8uaiSGxgTee623Uigm nPYzH8ArnHypRBXScKFr3X4aVtX0rBHEOPGzrRfpi2MNn6OPl/eUuPAMugTbpx6Cl564 9e6P/I+OlmwQQ2a53+VMZXMuGLLUjoP5wftpSF6nQwKIU54HI+wolE7GSDerv3tUmb5p nlgBTvJqjwlW+nv4VSfG5iY/LPZ2r6b//6ZWSkwyHXEmlhJUgQQGG3X8df5cPp/yOWSo 6t7w== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id 88-v6si2952592ple.76.2018.02.05.08.51.07; Mon, 05 Feb 2018 08:51:22 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753307AbeBEQuC (ORCPT + 99 others); Mon, 5 Feb 2018 11:50:02 -0500 Received: from mail.kernel.org ([198.145.29.99]:50654 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752986AbeBEQtz (ORCPT ); Mon, 5 Feb 2018 11:49:55 -0500 Received: from gandalf.local.home (cpe-172-100-180-131.stny.res.rr.com [172.100.180.131]) (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 0703821734; Mon, 5 Feb 2018 16:49:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0703821734 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=rostedt@goodmis.org Date: Mon, 5 Feb 2018 11:49:52 -0500 From: Steven Rostedt To: Adam Borowski Cc: "Tobin C. Harding" , Petr Mladek , Sergey Senozhatsky , linux-kernel@vger.kernel.org, Andrew Morton , Joe Perches , Kees Cook , "Roberts, William C" , Linus Torvalds , David Laight , Randy Dunlap , Geert Uytterhoeven Subject: Re: [PATCH] vsprintf: avoid misleading "(null)" for %px Message-ID: <20180205114952.6af99dff@gandalf.local.home> In-Reply-To: <20180205152218.hxgozi67zka4hgkf@angband.pl> References: <20180204174521.21383-1-kilobyte@angband.pl> <20180205094438.pfd7ffymlvklpxe7@pathway.suse.cz> <20180205100305.GO29988@eros> <20180205152218.hxgozi67zka4hgkf@angband.pl> X-Mailer: Claws Mail 3.16.0 (GTK+ 2.24.31; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 5 Feb 2018 16:22:19 +0100 Adam Borowski wrote: > My change touches %px only, where your concern doesn't apply. > > You're right, though, when it comes to %pK: > printk("%%pK: %pK, %%px: %px\n", 0, 0); > says > %pK: 00000000ba8bdc0a, %px: 0000000000000000 > > So what should we do? Avoid hashing 0? Print a special value? My personal opinion is that NULL should stay NULL and not be hashed. What security issue could be leaked by a NULL? I'm not a security person, that's a real question. -- Steve