Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261567AbVDQXtO (ORCPT ); Sun, 17 Apr 2005 19:49:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261568AbVDQXtO (ORCPT ); Sun, 17 Apr 2005 19:49:14 -0400 Received: from wproxy.gmail.com ([64.233.184.207]:53834 "EHLO wproxy.gmail.com") by vger.kernel.org with ESMTP id S261567AbVDQXsx convert rfc822-to-8bit (ORCPT ); Sun, 17 Apr 2005 19:48:53 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:reply-to:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=ap4yLceMcfZpZNSULtE2mC2psV1f2kYTgmeQ7ru8EY2yQ2pvEZtvAyjyVEXA7h7HagJUtgLjNCtphiZ5s9YqJYZZF4SK6Tb38SRzDEJhSuYT07mrTl+lo8FUPj1l3RllbHewvOKX+jhdd0YWmr34EW8tcAHIO5fQyji4qnDCiU4= Message-ID: <4ae3c140504171648d587669@mail.gmail.com> Date: Sun, 17 Apr 2005 19:48:50 -0400 From: Xin Zhao Reply-To: Xin Zhao To: Bernd Eckenfels Subject: Re: Why Ext2/3 needs immutable attribute? Cc: linux-kernel@vger.kernel.org In-Reply-To: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Content-Disposition: inline References: <4ae3c140504170912b36e9b1@mail.gmail.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1668 Lines: 34 We can certainly harden the system, but sometime the vulnerability in kernel is hard to detect and protect. For example, the brk() vulnerablitiy found in Linux kernel. All the security mechanisms you mentioned have to rely on a healthy kernel. Unfortunately, the kernel itself could be compromised too. Although it could be very difficult, thereotically speaking, any kernel level protection, including SELinux, could be disabled after the kernel is compromised. Am I missing some points here? On 4/17/05, Bernd Eckenfels wrote: > In article <4ae3c140504170912b36e9b1@mail.gmail.com> you wrote: > > Yes. I know, with immutable, even root cannot modify sensitive > > files. What I am curious is if an intruder has root access, he may > > have many ways to turn off the immutable protection and modify files. > > If you secure your system correctly (i.e make /dev/*mem imutable, disalow > module loading, restrict io... (and I admit it is quite complicated to find > all holes and secure it correctly without additional ptches like SELinux)) > then even root cant gt arround immutable or append only (without rebooting). > > Greetings > Bernd > - > 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/ > - 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/