From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:53370 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751772AbdJYL4t (ORCPT ); Wed, 25 Oct 2017 07:56:49 -0400 Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id v9PBu8K5069748 for ; Wed, 25 Oct 2017 07:56:48 -0400 Received: from e06smtp14.uk.ibm.com (e06smtp14.uk.ibm.com [195.75.94.110]) by mx0a-001b2d01.pphosted.com with ESMTP id 2dtshvhycf-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Wed, 25 Oct 2017 07:56:48 -0400 Received: from localhost by e06smtp14.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 25 Oct 2017 12:56:45 +0100 Subject: Re: [PATCH V3] EVM: Add support for portable signature format From: Mimi Zohar To: Matthew Garrett , linux-integrity@vger.kernel.org Cc: Dmitry Kasatkin , Mikhail Kurinnoi Date: Wed, 25 Oct 2017 07:56:40 -0400 In-Reply-To: <20171025095413.25794-1-mjg59@google.com> References: <20171025095413.25794-1-mjg59@google.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Message-Id: <1508932600.7367.13.camel@linux.vnet.ibm.com> Sender: linux-integrity-owner@vger.kernel.org List-ID: On Wed, 2017-10-25 at 02:54 -0700, Matthew Garrett wrote: > The EVM signature includes the inode number and (optionally) the > filesystem UUID, making it impractical to ship EVM signatures in > packages. This patch adds a new portable format intended to allow > distributions to include EVM signatures. It is identical to the existing > format but hardcodes the inode and generation numbers to 0 and does not > include the filesystem UUID even if the kernel is configured to do so. > > Removing the inode means that the metadata and signature from one file > could be copied to another file without invalidating it. This is avoided > by ensuring that an IMA xattr is present during EVM validation. > > Based on earlier work by Dmitry Kasatkin and Mikhail Kurinnoi. > > Signed-off-by: Matthew Garrett > Cc: Dmitry Kasatkin > Cc: Mikhail Kurinnoi > --- > V3: include feedback from Mimi. Some checks are still missing to prevent the portable/immutable signature from being replaced with an HMAC (eg. setattr, removexattr, etc). Mimi