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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D3A2CC433EF for ; Fri, 3 Jun 2022 04:28:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233015AbiFCE2o (ORCPT ); Fri, 3 Jun 2022 00:28:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57582 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229540AbiFCE2k (ORCPT ); Fri, 3 Jun 2022 00:28:40 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EC6EC65F4; Thu, 2 Jun 2022 21:28:38 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 84406B821C5; Fri, 3 Jun 2022 04:28:37 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D1501C385A9; Fri, 3 Jun 2022 04:28:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1654230516; bh=TDep2ZD1xO4DJlmrgaXkqq3uZa8dLlF0VXlkv4ea818=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=kFX3ysr0QVzY8bYj5xpxjrpgo60nRcssK4/JQrZk902y8kqmGGCj5Y7X6vUqStEQz RBZ9qe7ukTr/yHosA2xX+kV/+2ww5PLiXJbrcSxpmR1kRX1E6SKUiWrAosXoIwmwgk gg4+mF875B9oA7Q1T2Jo4O57VxotQpOYQMrbF5T+cLsmPabJVASijE0qxeN8PbB6GX Vu2cWlzDvDXzT1tWRgO6dE03dkRlsgEg3IkLAOKsn4gpRs0qM8b7H3KYoHes2Ob/I/ pMG5J6A09wbD0CsTW1NYqcTiYP1Ef2gBj0A9CyubymnKZcYaDwvhbJU+K9lyDJbK0h v1zqESOhu3T4w== Date: Fri, 3 Jun 2022 07:26:43 +0300 From: Jarkko Sakkinen To: Stefan Mahnke-Hartmann Cc: linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org, peterhuewe@gmx.de, jgg@ziepe.ca Subject: Re: [PATCH v2] tpm: Add upgrade/reduced mode support for TPM1.2 modules Message-ID: References: <20220602161301.4281-1-stefan.mahnke-hartmann@infineon.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220602161301.4281-1-stefan.mahnke-hartmann@infineon.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 02, 2022 at 06:13:01PM +0200, Stefan Mahnke-Hartmann wrote: > In case a TPM in failure mode is detected, the TPM should be accessible > through a transparent communication channel for analysing purposes (e.g. > TPM_GetTestResult) or a field upgrade. Since a TPM in failure mode has > similar reduced functionality as in field upgrade mode, the flag > TPM_CHIP_FLAG_FIRMWARE_UPGRADE is also valid. > > As described in TCG TPM Main Part1 Design Principles, Revision 116, > chapter 9.2.1. the TPM also allows an update function in case a TPM is > in failure mode. > > If the TPM in failure mode is detected, the function tpm1_auto_startup() > sets TPM_CHIP_FLAG_FIRMWARE_UPGRADE flag, which is used later during > driver initialization/deinitialization to disable functionality which > makes no sense or will fail in the current TPM state. The following > functionality is affected: > * Do not register TPM as a hwrng > * Do not get pcr allocation > * Do not register sysfs entries which provide information impossible to > obtain in limited mode > > Signed-off-by: Stefan Mahnke-Hartmann > --- > Changelog: > * v2: > * Commit message updated. > * Error handling for failed self test and other errors seperated. > . > drivers/char/tpm/tpm.h | 1 + > drivers/char/tpm/tpm1-cmd.c | 9 +++++++-- > 2 files changed, 8 insertions(+), 2 deletions(-) > > diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h > index 2163c6ee0d36..c0778498bc41 100644 > --- a/drivers/char/tpm/tpm.h > +++ b/drivers/char/tpm/tpm.h > @@ -56,6 +56,7 @@ enum tpm_addr { > #define TPM_ERR_DEACTIVATED 0x6 > #define TPM_ERR_DISABLED 0x7 > #define TPM_ERR_INVALID_POSTINIT 38 > +#define TPM_ERR_FAILEDSELFTEST 0x1C > > #define TPM_TAG_RQU_COMMAND 193 > > diff --git a/drivers/char/tpm/tpm1-cmd.c b/drivers/char/tpm/tpm1-cmd.c > index f7dc986fa4a0..fe21679ba0b6 100644 > --- a/drivers/char/tpm/tpm1-cmd.c > +++ b/drivers/char/tpm/tpm1-cmd.c > @@ -709,8 +709,13 @@ int tpm1_auto_startup(struct tpm_chip *chip) > if (rc) > goto out; > rc = tpm1_do_selftest(chip); > - if (rc) { > - dev_err(&chip->dev, "TPM self test failed\n"); > + if (rc == TPM_ERR_FAILEDSELFTEST) { > + dev_err(&chip->dev, "TPM self test failed, so the TPM has limited functionality\n"); Given that returning to a legit state, as far as driver is concerned, i.e. firmware upgrade mode, I would use the following warn here instead: dev_warn(&chip->dev, "TPM self test failed, switching to the firmware upgrade mode\n"); It's a success state because you are returning zero. > + /* A TPM in this state possibly allows or needs a firmware upgrade */ > + chip->flags |= TPM_CHIP_FLAG_FIRMWARE_UPGRADE; > + return 0; > + } else if (rc) { > + dev_err(&chip->dev, "TPM self test not successful\n"); Why did you change the error message? > goto out; > } > > -- > 2.25.1 > BR, Jarkko