Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S937250AbYCSV1W (ORCPT ); Wed, 19 Mar 2008 17:27:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754582AbYCSUCT (ORCPT ); Wed, 19 Mar 2008 16:02:19 -0400 Received: from perninha.conectiva.com.br ([200.140.247.100]:38639 "EHLO perninha.conectiva.com.br" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762420AbYCSUCR (ORCPT ); Wed, 19 Mar 2008 16:02:17 -0400 Date: Wed, 19 Mar 2008 15:12:12 -0300 From: "Luiz Fernando N. Capitulino" To: "Serge E. Hallyn" Cc: lkml , Linus Torvalds , Andrew Morton , Andrew Morgan , buraphalinuxserver@gmail.com Subject: Re: [PATCH 1/1] file capabilities: remove cap_task_kill() (-git) Message-ID: <20080319151212.571c4f72@mandriva.com.br> In-Reply-To: <20080319165635.GH5935@sergelap.ibm.com> References: <20080319165635.GH5935@sergelap.ibm.com> Organization: Mandriva X-Mailer: Claws Mail 3.3.1 (GTK+ 2.12.9; i586-mandriva-linux-gnu) 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: 1649 Lines: 40 Em Wed, 19 Mar 2008 11:56:35 -0500 "Serge E. Hallyn" escreveu: | (resending once against -git. I had sent against -stable in | http://lkml.org/lkml/2008/2/28/225. Without this patch, | atd is broken at least on some distros.) | | The original justification for cap_task_kill() was as follows: | | check_kill_permission() does appropriate uid equivalence checks. | However with file capabilities it becomes possible for an | unprivileged user to execute a file with file capabilities | resulting in a more privileged task with the same uid. | | However now that cap_task_kill() always returns 0 (permission | granted) when p->uid==current->uid, the whole hook is worthless, | and only likely to create more subtle problems in the corner cases | where it might still be called but return -EPERM. Those cases | are basically when uids are different but euid/suid is equivalent | as per the check in check_kill_permission(). | | One example of a still-broken application is 'at' for non-root users. | | This patch removes cap_task_kill(). | | Signed-off-by: Serge Hallyn | Acked-by: Andrew G. Morgan I've tested the -stable patch (no time to test this one, but it's exactly the same patch), not sure if this applies to this but... Tested-by: Luiz Fernando N. Capitulino -- Luiz Fernando N. Capitulino -- 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/