From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761927AbXHAMXq (ORCPT ); Wed, 1 Aug 2007 08:23:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1764300AbXHAMXd (ORCPT ); Wed, 1 Aug 2007 08:23:33 -0400 Received: from outpipe-village-512-1.bc.nu ([81.2.110.250]:41043 "EHLO the-village.bc.nu" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1764130AbXHAMXc (ORCPT ); Wed, 1 Aug 2007 08:23:32 -0400 Date: Wed, 1 Aug 2007 13:28:27 +0100 From: Alan Cox To: Eugene Teo Cc: linux-kernel@vger.kernel.org, "Kawai, Hidehiro" , Neil Horman , Bryan Wu Subject: Re: [PATCH 1/3] coredump: cleanup documentation for suid_dumpable Message-ID: <20070801132827.355c17e5@the-village.bc.nu> In-Reply-To: <46AFF092.6050802@kernel.sg> References: <20070731070238.GA2412@kernel.sg> <20070731070340.GB2412@kernel.sg> <20070731091337.5f3cb923@the-village.bc.nu> <46AFF092.6050802@kernel.sg> X-Mailer: Claws Mail 2.9.1 (GTK+ 2.10.13; i386-redhat-linux-gnu) Organization: Red Hat UK Cyf., Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SL4 1TE, Y Deyrnas Gyfunol. Cofrestrwyd yng Nghymru a Lloegr o'r rhif cofrestru 3798903 Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > > NAK - this feature is actively used and can be set by the sysctl > > interface. The PRCTL fixup was just a bug being fixed. The sysctl > > interface is still relevant. > > Thank you for correcting me. Appreciated. I am not aware that it is still > being actively used. May I know who or which program is using this feature? Not programs - people. When you want to debug a large complex system with multiple setuid applications it can rapidly get quite unpleasant. If you set /proc/sys/kernel/suid_dumpable to 2 and /proc/sys/kernel/core_pattern then it becomes possible to get hold of all the core dumps and debug the system as a whole. The system is not secure in this state but while you are doing that kind of debug on a devel system its usually acceptable. Secondly we don't break userspace interfaces except in extreme cases - proc/sys/kernel/suid_dumpable is a user space interface Alan