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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 E230BC636C9 for ; Mon, 19 Jul 2021 07:10:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BB0A06100B for ; Mon, 19 Jul 2021 07:10:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234728AbhGSHNK (ORCPT ); Mon, 19 Jul 2021 03:13:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44254 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234730AbhGSHNJ (ORCPT ); Mon, 19 Jul 2021 03:13:09 -0400 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B2EB1C061766 for ; Mon, 19 Jul 2021 00:10:09 -0700 (PDT) Received: from gallifrey.ext.pengutronix.de ([2001:67c:670:201:5054:ff:fe8d:eefb] helo=[IPv6:::1]) by metis.ext.pengutronix.de with esmtp (Exim 4.92) (envelope-from ) id 1m5NPg-0006h3-8C; Mon, 19 Jul 2021 09:10:04 +0200 Subject: Re: [PATCH] KEYS: trusted: Fix trusted key backends when building as module To: Andreas Rammhold , James Bottomley , Jarkko Sakkinen , Mimi Zohar , David Howells , James Morris , "Serge E . Hallyn" , linux-integrity@vger.kernel.org, keyrings@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, Pengutronix Kernel Team References: <20210716081722.4130161-1-andreas@rammhold.de> From: Ahmad Fatoum Message-ID: <0a684d56-66d0-184e-4853-9faafa2d243d@pengutronix.de> Date: Mon, 19 Jul 2021 09:10:01 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <20210716081722.4130161-1-andreas@rammhold.de> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 2001:67c:670:201:5054:ff:fe8d:eefb X-SA-Exim-Mail-From: a.fatoum@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-integrity@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org Hello Andreas, On 16.07.21 10:17, Andreas Rammhold wrote: > Before this commit the kernel could end up with no trusted key sources > even thought both of the currently supported backends (tpm & tee) were > compoiled as modules. This manifested in the trusted key type not being > registered at all. I assume (TPM) trusted key module use worked before the TEE rework? If so, an appropriate Fixes: Tag would then be in order. > When checking if a CONFIG_… preprocessor variable is defined we only > test for the builtin (=y) case and not the module (=m) case. By using > the IS_ENABLE(…) macro we to test for both cases. It looks to me like you could now provoke a link error if TEE is a module and built-in trusted key core tries to link against trusted_key_tee_ops. One solution for that IS_REACHABLE(). Another is to address the root cause, which is the inflexible trusted keys Kconfig description: - Trusted keys despite TEE support can still only be built when TCG_TPM is enabled - There is no support to have TEE or TPM enabled without using those for enabled trusted keys as well - As you noticed, module build of the backend has issues I addressed these three issues in a patch[1], a month ago, but have yet to receive feedback. [1]: https://lore.kernel.org/linux-integrity/f8285eb0135ba30c9d846cf9dd395d1f5f8b1efc.1624364386.git-series.a.fatoum@pengutronix.de/ Cheers, Ahmad > Signed-off-by: Andreas Rammhold > --- > security/keys/trusted-keys/trusted_core.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/security/keys/trusted-keys/trusted_core.c b/security/keys/trusted-keys/trusted_core.c > index d5c891d8d353..fd640614b168 100644 > --- a/security/keys/trusted-keys/trusted_core.c > +++ b/security/keys/trusted-keys/trusted_core.c > @@ -27,10 +27,10 @@ module_param_named(source, trusted_key_source, charp, 0); > MODULE_PARM_DESC(source, "Select trusted keys source (tpm or tee)"); > > static const struct trusted_key_source trusted_key_sources[] = { > -#if defined(CONFIG_TCG_TPM) > +#if IS_ENABLED(CONFIG_TCG_TPM) > { "tpm", &trusted_key_tpm_ops }, > #endif > -#if defined(CONFIG_TEE) > +#if IS_ENABLED(CONFIG_TEE) > { "tee", &trusted_key_tee_ops }, > #endif > }; > -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |