Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757336Ab3CTPDr (ORCPT ); Wed, 20 Mar 2013 11:03:47 -0400 Received: from terminus.zytor.com ([198.137.202.10]:47904 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756079Ab3CTPDo (ORCPT ); Wed, 20 Mar 2013 11:03:44 -0400 User-Agent: K-9 Mail for Android In-Reply-To: <1363785354.2553.15.camel@x230.sbx07502.somerma.wayport.net> References: <1363642353-30749-1-git-send-email-matthew.garrett@nebula.com> <51490ABD.3050205@zytor.com> <1363785354.2553.15.camel@x230.sbx07502.somerma.wayport.net> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Subject: Re: [PATCH 01/12] Security: Add CAP_COMPROMISE_KERNEL From: "H. Peter Anvin" Date: Wed, 20 Mar 2013 08:03:37 -0700 To: Matthew Garrett CC: "linux-kernel@vger.kernel.org" , "linux-security-module@vger.kernel.org" , "linux-efi@vger.kernel.org" , "kexec@lists.infradead.org" , "linux-pci@vger.kernel.org" Message-ID: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1121 Lines: 27 CAP_SYS_RAWIO is definitely inappropriate there. Matthew Garrett wrote: >On Tue, 2013-03-19 at 18:02 -0700, H. Peter Anvin wrote: > >> Looking at it in detail, EVERYTHING in CAP_SYS_RAWIO has the >possibility >> of compromising the kernel, because they let device drivers be >bypassed, >> which means arbitrary DMA, which means you have everything. > >Having checked again, I don't think this is true. The most obvious case >is libata, which uses CAP_SYS_RAWIO to limit the ability to send raw >ATA >commands. Being able to do so clearly permits userspace to avoid any >kind of policy the vfs has put in place, but there's no obvious way for >the user to modify the running kernel. Are you suggesting that removing >the CAP_SYS_RAWIO check there would be reasonable? -- Sent from my mobile phone. Please excuse brevity and lack of formatting. -- 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/