Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755478Ab0KIMJ3 (ORCPT ); Tue, 9 Nov 2010 07:09:29 -0500 Received: from earthlight.etchedpixels.co.uk ([81.2.110.250]:45646 "EHLO www.etchedpixels.co.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755407Ab0KIMJ2 (ORCPT ); Tue, 9 Nov 2010 07:09:28 -0500 Date: Tue, 9 Nov 2010 12:06:49 +0000 From: Alan Cox To: Dan Rosenberg Cc: linux-kernel@vger.kernel.org, security@kernel.org, stable@kernel.org Subject: Re: [PATCH] Restrict unprivileged access to kernel syslog Message-ID: <20101109120649.62b487e8@lxorguk.ukuu.org.uk> In-Reply-To: <1289273338.6287.128.camel@dan> References: <1289273338.6287.128.camel@dan> X-Mailer: Claws Mail 3.7.6 (GTK+ 2.18.9; x86_64-redhat-linux-gnu) Face: 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 Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 972 Lines: 19 On Mon, 08 Nov 2010 22:28:58 -0500 Dan Rosenberg wrote: > The kernel syslog contains debugging information that is often useful > during exploitation of other vulnerabilities, such as kernel heap > addresses. Rather than futilely attempt to sanitize hundreds (or > thousands) of printk statements and simultaneously cripple useful > debugging functionality, it is far simpler to create an option that > prevents unprivileged users from reading the syslog. Except for anything that appears on the screen - which is remotely readable via the screen access APIs. Looks sane to me (pointless but sane) and the checks match the ones needed to redirect the console so you need CAP_SYS_ADMIN either way. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/