From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757371Ab2BMRXy (ORCPT ); Mon, 13 Feb 2012 12:23:54 -0500 Received: from lxorguk.ukuu.org.uk ([81.2.110.251]:57785 "EHLO lxorguk.ukuu.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757275Ab2BMRXw (ORCPT ); Mon, 13 Feb 2012 12:23:52 -0500 Date: Mon, 13 Feb 2012 17:25:27 +0000 From: Alan Cox To: Paolo Bonzini Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, Jens Axboe , Linus Torvalds Subject: Re: [PATCH] block: avoid false positive warnings on ioctl to partition Message-ID: <20120213172527.40ac390b@pyramind.ukuu.org.uk> In-Reply-To: <1329153206-31355-1-git-send-email-pbonzini@redhat.com> References: <1329153206-31355-1-git-send-email-pbonzini@redhat.com> X-Mailer: Claws Mail 3.8.0 (GTK+ 2.24.8; 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 > Therefore, this patch silently blocks all ioctls except SG_IO, since > all of them turned out to be false positives; in case some escaped, it > should be easily diagnosable or at least bisectable. The warning text > is separated for root and non-root, and the deprecation period for root > users is set to end a year from now. NAK. Firstly blocking CAP_SYS_RAWIO access by any means to a partition is itself nonsense as the process has enough privilege to go poke the controller I/O registers by hand. That's a gratuitious API breakage. Secondly SG_IO allows users to read and write blocks outside their partition as far as I can see from the verify logic. You either need to block it or smarten up the filter. What were the SG_IO command blocks that were caught ? It's going to be pretty trivial to add a filter->partition_ok to some of them if need be. Anyway it fails both by stopping valid stuff and not stopping insecure and unsafe stuff. Alan