Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756611AbYLCX1v (ORCPT ); Wed, 3 Dec 2008 18:27:51 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751822AbYLCX1m (ORCPT ); Wed, 3 Dec 2008 18:27:42 -0500 Received: from an-out-0708.google.com ([209.85.132.247]:14115 "EHLO an-out-0708.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751089AbYLCX1l (ORCPT ); Wed, 3 Dec 2008 18:27:41 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version :content-type:content-transfer-encoding:content-disposition :references; b=q8hQI+h6t2A/zqpBSHzvZTe8D4jfKIN1TTToxfTwbA1k2t2/U370iXGoWgIM5uBEqu E5wkyNZH5uySjjzc0pNVF9l5DRv8lFvNuLEFyUSc/FbKI3MePCpnfZ1nUvZgxFKhRmh1 MjNLSLWzhZEfeS2bVGLl4oR1UbHTkxPR38zHI= Message-ID: <804dabb00812031527k3fae11dcnef3b1696c3d136f8@mail.gmail.com> Date: Thu, 4 Dec 2008 07:27:39 +0800 From: "Peter Teoh" To: "Geoffrey McRae" Subject: Re: New Security Features, Please Comment Cc: "Alan Cox" , "Nick Andrew" , linux-kernel@vger.kernel.org In-Reply-To: <20081203230820.4473a162@lxorguk.ukuu.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <1228260494.24232.21.camel@compy.ivent.com.au> <20081203005338.6472db7a@lxorguk.ukuu.org.uk> <1228268657.6679.4.camel@lappy.spacevs.com> <20081203124252.GD11807@mail.local.tull.net> <1228344292.6993.27.camel@lappy.spacevs.com> <20081203230820.4473a162@lxorguk.ukuu.org.uk> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1017 Lines: 27 On Thu, Dec 4, 2008 at 7:08 AM, Alan Cox wrote: >> The children are pre-forked, so the overhead is in the setup... then >> when the app recieves a request, it sets the child's uid to the uid of >> the website, and then passes the request to the child, which, now, the >> child is running as the website owner. > > But the child process may already have been trojanned by a previous user > so it gains you nothing. > Yes, I thought so too. The trojanized child, even though most of the time unprivileged, can wait for that window of opportunity when its privilege is escalated, by polling, and when it received the privilege, immediate jump into action. Thanks. -- Regards, Peter Teoh Ernest Hemingway - "Never mistake motion for action." -- 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/