From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752646Ab3BMFjd (ORCPT ); Wed, 13 Feb 2013 00:39:33 -0500 Received: from co1ehsobe004.messaging.microsoft.com ([216.32.180.187]:20596 "EHLO co1outboundpool.messaging.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751634Ab3BMFj3 (ORCPT ); Wed, 13 Feb 2013 00:39:29 -0500 X-Forefront-Antispam-Report: CIP:157.56.236.101;KIP:(null);UIP:(null);IPV:NLI;H:BY2PRD0510HT003.namprd05.prod.outlook.com;RD:none;EFVD:NLI X-SpamScore: -3 X-BigFish: PS-3(zz98dI936eI1432Izz1f42h1ee6h1de0h1202h1e76h1d1ah1d2ahzzz2fh2a8h668h839h93fhd24he5bhf0ah1288h12a5h12a9h12bdh137ah13b6h1441h1504h1537h153bh162dh1631h1758h18e1h1946h19b5h1155h) From: Matthew Garrett To: "H. Peter Anvin" CC: Borislav Petkov , Kees Cook , LKML , Thomas Gleixner , Ingo Molnar , "x86@kernel.org" , "linux-efi@vger.kernel.org" , linux-security-module Subject: Re: [PATCH] x86: Lock down MSR writing in secure boot Thread-Topic: [PATCH] x86: Lock down MSR writing in secure boot Thread-Index: AQHOBjA7mQsIMlqU/k+EElzc7Yz1iZhwVXgAgAAAbACAAAawAIAACLcAgAABPICAAAKrAIAAAdKAgAAHwICAABjCAIAAChOAgAAFkwCAACBDAIAAAhCAgABYQICAAC3GgIAAX64AgAVYBQCAAFFaAA== Date: Wed, 13 Feb 2013 05:39:22 +0000 Message-ID: <1360733962.18083.30.camel@x230.lan> References: <1360355671.18083.18.camel@x230.lan> <51157C9C.6030501@zytor.com> <20130208230655.GB28990@pd.tnic> <1360366012.18083.21.camel@x230.lan> <5115A4CC.3080102@zytor.com> <1360373383.18083.23.camel@x230.lan> <20130209092925.GA17728@pd.tnic> <1360422712.18083.24.camel@x230.lan> <511AE2CC.5040705@zytor.com> In-Reply-To: <511AE2CC.5040705@zytor.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.255.84.4] Content-Type: text/plain; charset="utf-8" Content-ID: MIME-Version: 1.0 X-OriginatorOrg: nebula.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by mail.home.local id r1D5dYPf028019 On Tue, 2013-02-12 at 16:48 -0800, H. Peter Anvin wrote: > OK... what none of this gets into: > > Why should CAP_RAWIO be allowed on a secure boot system, when there are > 2^n known ways of compromise a system with CAP_RAWIO? CAP_SYS_RAWIO seems to have ended up being a catchall of "Maybe someone who isn't entirely root should be able to do this", and not everything it covers is equivalent to being able to compromise the running kernel. I wouldn't argue with the idea that maybe we should just reappraise most of the current uses of CAP_SYS_RAWIO, but removing capability checks from places that currently have them seems like an invitation for userspace breakage. {.n++%ݶw{.n+{G{ayʇڙ,jfhz_(階ݢj"mG?&~iOzv^m ?I