Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932212AbdGSLOf (ORCPT ); Wed, 19 Jul 2017 07:14:35 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:48204 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932123AbdGSLOc (ORCPT ); Wed, 19 Jul 2017 07:14:32 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Josh Zimmerman , Jarkko Sakkinen , James Morris Subject: [PATCH 4.4 42/57] tpm: Issue a TPM2_Shutdown for TPM2 devices. Date: Wed, 19 Jul 2017 13:12:48 +0200 Message-Id: <20170719111251.668378854@linuxfoundation.org> X-Mailer: git-send-email 2.13.3 In-Reply-To: <20170719111249.973558472@linuxfoundation.org> References: <20170719111249.973558472@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3436 Lines: 101 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Josh Zimmerman commit d1bd4a792d3961a04e6154118816b00167aad91a upstream. If a TPM2 loses power without a TPM2_Shutdown command being issued (a "disorderly reboot"), it may lose some state that has yet to be persisted to NVRam, and will increment the DA counter. After the DA counter gets sufficiently large, the TPM will lock the user out. NOTE: This only changes behavior on TPM2 devices. Since TPM1 uses sysfs, and sysfs relies on implicit locking on chip->ops, it is not safe to allow this code to run in TPM1, or to add sysfs support to TPM2, until that locking is made explicit. Signed-off-by: Josh Zimmerman Cc: stable@vger.kernel.org Fixes: 74d6b3ceaa17 ("tpm: fix suspend/resume paths for TPM 2.0") Reviewed-by: Jarkko Sakkinen Tested-by: Jarkko Sakkinen Signed-off-by: Jarkko Sakkinen Signed-off-by: James Morris Signed-off-by: Greg Kroah-Hartman --- drivers/char/tpm/tpm-chip.c | 36 ++++++++++++++++++++++++++++++++++++ drivers/char/tpm/tpm-sysfs.c | 7 +++++++ 2 files changed, 43 insertions(+) --- a/drivers/char/tpm/tpm-chip.c +++ b/drivers/char/tpm/tpm-chip.c @@ -124,6 +124,41 @@ static void tpm_dev_release(struct devic kfree(chip); } + +/** + * tpm_class_shutdown() - prepare the TPM device for loss of power. + * @dev: device to which the chip is associated. + * + * Issues a TPM2_Shutdown command prior to loss of power, as required by the + * TPM 2.0 spec. + * Then, calls bus- and device- specific shutdown code. + * + * XXX: This codepath relies on the fact that sysfs is not enabled for + * TPM2: sysfs uses an implicit lock on chip->ops, so this could race if TPM2 + * has sysfs support enabled before TPM sysfs's implicit locking is fixed. + */ +static int tpm_class_shutdown(struct device *dev) +{ + struct tpm_chip *chip = container_of(dev, struct tpm_chip, dev); + + if (chip->flags & TPM_CHIP_FLAG_TPM2) { + down_write(&chip->ops_sem); + tpm2_shutdown(chip, TPM2_SU_CLEAR); + chip->ops = NULL; + up_write(&chip->ops_sem); + } + /* Allow bus- and device-specific code to run. Note: since chip->ops + * is NULL, more-specific shutdown code will not be able to issue TPM + * commands. + */ + if (dev->bus && dev->bus->shutdown) + dev->bus->shutdown(dev); + else if (dev->driver && dev->driver->shutdown) + dev->driver->shutdown(dev); + return 0; +} + + /** * tpmm_chip_alloc() - allocate a new struct tpm_chip instance * @dev: device to which the chip is associated @@ -166,6 +201,7 @@ struct tpm_chip *tpmm_chip_alloc(struct dev_set_drvdata(dev, chip); chip->dev.class = tpm_class; + chip->dev.class->shutdown = tpm_class_shutdown; chip->dev.release = tpm_dev_release; chip->dev.parent = dev; #ifdef CONFIG_ACPI --- a/drivers/char/tpm/tpm-sysfs.c +++ b/drivers/char/tpm/tpm-sysfs.c @@ -284,6 +284,13 @@ static const struct attribute_group tpm_ int tpm_sysfs_add_device(struct tpm_chip *chip) { int err; + + /* XXX: If you wish to remove this restriction, you must first update + * tpm_sysfs to explicitly lock chip->ops. + */ + if (chip->flags & TPM_CHIP_FLAG_TPM2) + return 0; + err = sysfs_create_group(&chip->dev.parent->kobj, &tpm_dev_group);