From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9BCE3C43460 for ; Wed, 7 Apr 2021 20:15:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 58AB5611C1 for ; Wed, 7 Apr 2021 20:15:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1356036AbhDGUPw (ORCPT ); Wed, 7 Apr 2021 16:15:52 -0400 Received: from mail.kernel.org ([198.145.29.99]:52306 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1356007AbhDGUPv (ORCPT ); Wed, 7 Apr 2021 16:15:51 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3190D611C9; Wed, 7 Apr 2021 20:15:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1617826541; bh=1+gRdzaXa3CPpAICXcQ2ksebFZYF8WM8K6fcrZV+oJ4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=OdCESpHTky9J9E1NOMUt4gMFtvVXqDdAk2IKL2MKS+jjK2s7f28169dWaZiavTlPE 50pHToXGIgxL+j4mjCIzfCw0zfxYW/eucxOx0J+TjBE86DYMzCLihStlTo/NWXChkl PgVriYx+/TQSxlvCEVg6eSkKl/BZGTu3KShmz8Y7Uf0AksTJf03/59wl9GDtVaM2N8 T8lqTrrXYFDa/OOusL+WtW8l2fn8o7wZjfNGO/ITsrHiPRvDbBBEQwnuLK92U/O8pU c6336t0ZeXuNSaNujkoUdB1bj/IW2ANiYwPj/dJqVA4zR3HAF1UEcKmtlgGxUfnDM7 kIaX0wLGnnfMA== Date: Wed, 7 Apr 2021 23:15:38 +0300 From: Jarkko Sakkinen To: Stefan Berger Cc: Mimi Zohar , keyrings@vger.kernel.org, dhowells@redhat.com, nayna@linux.ibm.com, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/2] Add support for ECDSA-signed kernel modules Message-ID: References: <20210406185340.1079403-1-stefanb@linux.ibm.com> <5a217256a53f9c33aba4528ab0393b84c42b1813.camel@linux.ibm.com> <70f7b2a4-ec3c-3da0-bcb6-7c96f391c1c1@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <70f7b2a4-ec3c-3da0-bcb6-7c96f391c1c1@linux.ibm.com> Precedence: bulk List-ID: On Wed, Apr 07, 2021 at 01:53:24PM -0400, Stefan Berger wrote: > > On 4/7/21 12:10 PM, Mimi Zohar wrote: > > On Wed, 2021-04-07 at 18:53 +0300, Jarkko Sakkinen wrote: > > > On Tue, Apr 06, 2021 at 02:53:38PM -0400, Stefan Berger wrote: > > > > This series adds support for ECDSA-signed kernel modules. > > > > > > > > The first patch in this series attempts to address the issue where a > > > > developer created an ECDSA key for signing modules and then falls back > > > > to compiling an older version of the kernel that does not support > > > > ECDSA keys. In this case this patch would delete that ECDSA key if it is > > > > in certs/signing_key.pem and trigger the creation of an RSA key. However, > > > > for this to work this patch would have to be applied to previous versions > > > > of the kernel but would also only work for the developer if he/she used a > > > > stable version of the kernel to which this patch was applied. So whether > > > > this patch actually achieves the wanted effect is not always guaranteed. > > > Just wondering why the key needs to be removed in the fallback. > Because if you signed an older kernel's modules with the ECDSA key it won't > be able to load the modules... > > The main concern is with bisecting the kernel. Either elliptic curve > > support or the first patch needs to be backported. This patch will > > cause the kernel module signing key to be regenerated. > > > This assumes of course that one will bisect via the stable kernels where > this 1st patch has been applied. Not sure whether that's what people will > do. In any case, sounds non-trivial issue enough ought to be documented in the commit message. /Jarkko