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=-17.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,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 61EE2C432BE for ; Sat, 21 Aug 2021 17:50:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4E74460F42 for ; Sat, 21 Aug 2021 17:50:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232729AbhHURu5 (ORCPT ); Sat, 21 Aug 2021 13:50:57 -0400 Received: from smtp1.axis.com ([195.60.68.17]:57069 "EHLO smtp1.axis.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231969AbhHURuw (ORCPT ); Sat, 21 Aug 2021 13:50:52 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=axis.com; q=dns/txt; s=axis-central1; t=1629568213; x=1661104213; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=yLDM+vNDD8JHbT4us+SoFhJVh82f80/OA2KMHUrnBOQ=; b=BMRjDBAG1YeShviwbkedSjfEEjyfUlngiXs7B/Y24xaTYBDSKjdX1fTj Ot/ct6ZcLxuNGp6ZQSSBvePWrawCCAbhMInY+Eyfmo0vWp8Qwtvgb4R8z QWHXk3O0cFiVt9fw5N5VPTgjuFYLY3peTbzQ8pQVphIYahi7KeEIpYZhy BD/HsaTBn4AU+9OOk1CxDVyTfHcQapbRdi9302loTwJCNVgaJ0wFX9yC8 TrIiV+CCFeSdOqEjlbsznL1P0N89eBMcEYIFy69JZAetXqvYiRD2/YwXg kZdELdOCmVuQhLh7hRXWV/71ScjS0ZMw6xuCtNKt2EAOj8PvdJ+rvKFFo A==; Date: Sat, 21 Aug 2021 19:53:01 +0200 From: Borys Movchan To: Jarkko Sakkinen CC: Peter Huewe , Jason Gunthorpe , kernel , "linux-integrity@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH v5] tpm: Add Upgrade/Reduced mode support for TPM2 modules Message-ID: <20210821175301.7sjqc736pwdi6k5v@lnxborysmn.se.axis.com> References: <20210809174731.27924-1-borysmn@axis.com> <20210810175312.ziglxdlqimsmxbak@kernel.org> <20210815172858.GA14375@lnxborysmn.se.axis.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20210815172858.GA14375@lnxborysmn.se.axis.com> User-Agent: NeoMutt/20180716 X-Originating-IP: [10.0.5.60] X-ClientProxiedBy: se-mail07w.axis.com (10.20.40.13) To se-mail07w.axis.com (10.20.40.13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Aug 15, 2021 at 07:28:58PM +0200, Borys Movchan wrote: > On Tue, Aug 10, 2021 at 07:53:12PM +0200, Jarkko Sakkinen wrote: > > On Mon, Aug 09, 2021 at 07:47:30PM +0200, Borys Movchan wrote: > > > If something went wrong during the TPM firmware upgrade, like power > > > failure or the firmware image file get corrupted, the TPM might end > > > up in Upgrade or Failure mode upon the next start. The state is > > > persistent between the TPM power cycle/restart. > > > > > > According to TPM specification: > > > * If the TPM is in Upgrade mode, it will answer with TPM2_RC_UPGRADE > > > to all commands except Field Upgrade related ones. > > > * If the TPM is in Failure mode, it will allow performing TPM > > > initialization but will not provide any crypto operations. > > > Will happily respond to Field Upgrade calls. > > > > > > Change the behavior of the tpm2_auto_startup(), so it detects the active > > > running mode of the TPM by adding the following checks. If > > > tpm2_do_selftest() call returns TPM2_RC_UPGRADE, the TPM is in Upgrade > > > mode. > > > If the TPM is in Failure mode, it will successfully respond to both > > > tpm2_do_selftest() and tpm2_startup() calls. Although, will fail to > > > answer to tpm2_get_cc_attrs_tbl(). Use this fact to conclude that TPM is > > > in Failure mode. > > > > > > If detected that the TPM is in the Upgrade or Failure mode, the function > > > sets TPM_CHIP_FLAG_LIMITED_MODE flag. > > > > Does this apply for TPM 1.2? Are there differences? > > > > Actually I am not sure, I am working with TPM 2 exclusively have no > knowledge regarding other versions. > > > > The limited mode flag is used later during driver > > > initialization/deinitialization to disable functionality which makes no > > > sense or will fail in the current TPM state. Following functionality is > > > affected: > > > * do not register TPM as a hwrng > > > * do not register sysfs entries which provide information impossible to > > > obtain in limited mode > > > * do not register resource managed character device > > > > Maybe for consistency call it TPM_CHIP_FLAG_UPGRADE_MODE? It makes easier > > to "connect dots" later on (has probably something to do TPM_RC_UPGRADE). > > > > > > My idea was to group both Failure and Upgrade mode and call them limited > mode. As functionality of the TPM is limited in both of them. I was > afraid that if I call it upgrade mode and map failure mode into it, it > might get confusing. So please confirm that you prefer to name the flag > as TPM_CHIP_FLAG_UPGRADE_MODE. > > > > > > > Signed-off-by: Borys Movchan > > > --- > > > > > > Notes: > > > v2: > > > * Commit message updated. > > > > > > v3: > > > * Commit message reworked. > > > > > > v4: > > > * Description of how tpm2_auto_startup() detects the mode added to > > > commit message. > > > > > > v5: > > > * Introduce global flag: TPM_CHIP_FLAG_LIMITED_MODE. > > > * Add checks for the flag in places that will not work properly when TPM > > > functionality is limited. > > > * Avoid registering sysfs and character device entries that have no useful > > > function in limited mode. > > > * Do not register TPM as a hwrng. > > > * Do not try to obtain any crypto-related properties from TPM as it will fail > > > in limited mode. > > > > > > drivers/char/tpm/tpm-chip.c | 16 ++++++++++------ > > > drivers/char/tpm/tpm-sysfs.c | 3 +++ > > > drivers/char/tpm/tpm2-cmd.c | 13 ++++++++++++- > > > include/linux/tpm.h | 2 ++ > > > 4 files changed, 27 insertions(+), 7 deletions(-) > > > > > > diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c > > > index ddaeceb7e109..8d159db39392 100644 > > > --- a/drivers/char/tpm/tpm-chip.c > > > +++ b/drivers/char/tpm/tpm-chip.c > > > @@ -444,7 +444,7 @@ static int tpm_add_char_device(struct tpm_chip *chip) > > > return rc; > > > } > > > > > > - if (chip->flags & TPM_CHIP_FLAG_TPM2) { > > > + if (chip->flags & TPM_CHIP_FLAG_TPM2 && !(chip->flags & TPM_CHIP_FLAG_LIMITED_MODE)) { > > > > You cannot rely on validity of TPM_CHIP_FLAG_TPM2, as tpm_tis driver > > uses a TPM command to probe the TPM version. > > > > Good point, will fix in next patch version. > After giving it a 2nd thought, I would say, it doesn't meter in this case. Changing the condition to ignore TPM_CHIP_FLAG_TPM2 will not change the behavior of the condition at all. Please let me know what should I do next. > > > rc = cdev_device_add(&chip->cdevs, &chip->devs); > > > if (rc) { > > > dev_err(&chip->devs, > > > @@ -506,7 +506,8 @@ static int tpm_add_legacy_sysfs(struct tpm_chip *chip) > > > struct attribute **i; > > > int rc; > > > > > > - if (chip->flags & (TPM_CHIP_FLAG_TPM2 | TPM_CHIP_FLAG_VIRTUAL)) > > > + if (chip->flags & (TPM_CHIP_FLAG_TPM2 | TPM_CHIP_FLAG_VIRTUAL) || > > > + chip->flags & TPM_CHIP_FLAG_LIMITED_MODE) > > > return 0; > > > > > > rc = compat_only_sysfs_link_entry_to_kobj( > > > @@ -536,7 +537,7 @@ static int tpm_hwrng_read(struct hwrng *rng, void *data, size_t max, bool wait) > > > > > > static int tpm_add_hwrng(struct tpm_chip *chip) > > > { > > > - if (!IS_ENABLED(CONFIG_HW_RANDOM_TPM)) > > > + if (!IS_ENABLED(CONFIG_HW_RANDOM_TPM) || chip->flags & TPM_CHIP_FLAG_LIMITED_MODE) > > > return 0; > > > > > > snprintf(chip->hwrng_name, sizeof(chip->hwrng_name), > > > @@ -550,6 +551,9 @@ static int tpm_get_pcr_allocation(struct tpm_chip *chip) > > > { > > > int rc; > > > > > > + if (chip->flags & TPM_CHIP_FLAG_LIMITED_MODE) > > > + return 0; > > > + > > > rc = (chip->flags & TPM_CHIP_FLAG_TPM2) ? > > > tpm2_get_pcr_allocation(chip) : > > > tpm1_get_pcr_allocation(chip); > > > @@ -612,7 +616,7 @@ int tpm_chip_register(struct tpm_chip *chip) > > > return 0; > > > > > > out_hwrng: > > > - if (IS_ENABLED(CONFIG_HW_RANDOM_TPM)) > > > + if (IS_ENABLED(CONFIG_HW_RANDOM_TPM) && !(chip->flags & TPM_CHIP_FLAG_LIMITED_MODE)) > > > hwrng_unregister(&chip->hwrng); > > > out_ppi: > > > tpm_bios_log_teardown(chip); > > > @@ -637,10 +641,10 @@ EXPORT_SYMBOL_GPL(tpm_chip_register); > > > void tpm_chip_unregister(struct tpm_chip *chip) > > > { > > > tpm_del_legacy_sysfs(chip); > > > - if (IS_ENABLED(CONFIG_HW_RANDOM_TPM)) > > > + if (IS_ENABLED(CONFIG_HW_RANDOM_TPM) && !(chip->flags & TPM_CHIP_FLAG_LIMITED_MODE)) > > > hwrng_unregister(&chip->hwrng); > > > tpm_bios_log_teardown(chip); > > > - if (chip->flags & TPM_CHIP_FLAG_TPM2) > > > + if (chip->flags & TPM_CHIP_FLAG_TPM2 && !(chip->flags & TPM_CHIP_FLAG_LIMITED_MODE)) > > > cdev_device_del(&chip->cdevs, &chip->devs); > > > tpm_del_char_device(chip); > > > } > > > diff --git a/drivers/char/tpm/tpm-sysfs.c b/drivers/char/tpm/tpm-sysfs.c > > > index 63f03cfb8e6a..43ea9c66342d 100644 > > > --- a/drivers/char/tpm/tpm-sysfs.c > > > +++ b/drivers/char/tpm/tpm-sysfs.c > > > @@ -478,6 +478,9 @@ void tpm_sysfs_add_device(struct tpm_chip *chip) > > > { > > > int i; > > > > > > + if (chip->flags & TPM_CHIP_FLAG_LIMITED_MODE) > > > + return; > > > + > > > WARN_ON(chip->groups_cnt != 0); > > > > > > if (chip->flags & TPM_CHIP_FLAG_TPM2) > > > diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c > > > index a25815a6f625..598d62695310 100644 > > > --- a/drivers/char/tpm/tpm2-cmd.c > > > +++ b/drivers/char/tpm/tpm2-cmd.c > > > @@ -729,7 +729,12 @@ int tpm2_auto_startup(struct tpm_chip *chip) > > > goto out; > > > > > > rc = tpm2_do_selftest(chip); > > > - if (rc && rc != TPM2_RC_INITIALIZE) > > > + if (rc == TPM2_RC_UPGRADE) { > > > + dev_info(&chip->dev, "TPM is in upgrade mode, functionality limited\n"); > > > + chip->flags |= TPM_CHIP_FLAG_LIMITED_MODE; > > > + rc = 0; > > > + goto out; > > > + } else if (rc && rc != TPM2_RC_INITIALIZE) > > > goto out; > > > > > > if (rc == TPM2_RC_INITIALIZE) { > > > @@ -743,6 +748,12 @@ int tpm2_auto_startup(struct tpm_chip *chip) > > > } > > > > > > rc = tpm2_get_cc_attrs_tbl(chip); > > > + if (rc) { > > > > Why all rc's apply? > > > > Different vendors return different error codes here. Some, like STM > return vendor specific ones. > > > > + dev_info(&chip->dev, "TPM is in failure mode, functionality limited\n"); > > > > Here is again a different name for the same thing (different than > > TPM_CHIP_FLAG_LIMITED_MODE). > > > > This check is triggered only if TPM is in Failure mode. It is different > from Upgrade mode. > > > > + chip->flags |= TPM_CHIP_FLAG_LIMITED_MODE; > > > + rc = 0; > > > + goto out; > > > + } > > > > > > out: > > > if (rc > 0) > > > diff --git a/include/linux/tpm.h b/include/linux/tpm.h > > > index aa11fe323c56..231d7c7ec913 100644 > > > --- a/include/linux/tpm.h > > > +++ b/include/linux/tpm.h > > > @@ -207,6 +207,7 @@ enum tpm2_return_codes { > > > TPM2_RC_INITIALIZE = 0x0100, /* RC_VER1 */ > > > TPM2_RC_FAILURE = 0x0101, > > > TPM2_RC_DISABLED = 0x0120, > > > + TPM2_RC_UPGRADE = 0x012D, > > > TPM2_RC_COMMAND_CODE = 0x0143, > > > TPM2_RC_TESTING = 0x090A, /* RC_WARN */ > > > TPM2_RC_REFERENCE_H0 = 0x0910, > > > @@ -277,6 +278,7 @@ enum tpm_chip_flags { > > > TPM_CHIP_FLAG_HAVE_TIMEOUTS = BIT(4), > > > TPM_CHIP_FLAG_ALWAYS_POWERED = BIT(5), > > > TPM_CHIP_FLAG_FIRMWARE_POWER_MANAGED = BIT(6), > > > + TPM_CHIP_FLAG_LIMITED_MODE = BIT(7), > > > }; > > > > > > #define to_tpm_chip(d) container_of(d, struct tpm_chip, dev) > > > -- > > > 2.20.1 > > > > > > > > > > /Jarkko > > Kind regards, > Borys Kind regards, Borys