From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754888AbbCRGR3 (ORCPT ); Wed, 18 Mar 2015 02:17:29 -0400 Received: from mga02.intel.com ([134.134.136.20]:13782 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750896AbbCRGR1 (ORCPT ); Wed, 18 Mar 2015 02:17:27 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.11,421,1422950400"; d="scan'208";a="700284850" From: Jarkko Sakkinen To: Peter Huewe , Ashley Lai , Marcel Selhorst Cc: tpmdd-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, christophe.ricard@gmail.com, jason.gunthorpe@obsidianresearch.com, stefanb@linux.vnet.ibm.com, Jarkko Sakkinen Subject: [PATCH v2] tpm: fix: sanitized code paths in tpm_chip_register() Date: Wed, 18 Mar 2015 08:17:14 +0200 Message-Id: <1426659434-4003-1-git-send-email-jarkko.sakkinen@linux.intel.com> X-Mailer: git-send-email 2.1.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org I started to work with PPI interface so that it would be available under character device sysfs directory and realized that chip registeration was still too messy. In TPM 1.x in some rare scenarios (errors that almost never occur) wrong order in deinitialization steps was taken in teardown. I reproduced these scenarios by manually inserting error codes in the place of the corresponding function calls. The key problem is that the teardown is messy with two separate code paths (this was inherited when moving code from tpm-interface.c). Moved TPM 1.x specific register/unregister functionality to own helper functions and added single code path for teardown in tpm_chip_register(). Now the code paths have been fixed and it should be easier to review later on this part of the code. Signed-off-by: Jarkko Sakkinen --- drivers/char/tpm/tpm-chip.c | 66 ++++++++++++++++++++++++++++----------------- 1 file changed, 42 insertions(+), 24 deletions(-) diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c index e096e9c..283f00a 100644 --- a/drivers/char/tpm/tpm-chip.c +++ b/drivers/char/tpm/tpm-chip.c @@ -170,6 +170,41 @@ static void tpm_dev_del_device(struct tpm_chip *chip) device_unregister(&chip->dev); } +static int tpm1_chip_register(struct tpm_chip *chip) +{ + int rc; + + if (chip->flags & TPM_CHIP_FLAG_TPM2) + return 0; + + rc = tpm_sysfs_add_device(chip); + if (rc) + return rc; + + rc = tpm_add_ppi(chip); + if (rc) { + tpm_sysfs_del_device(chip); + return rc; + } + + chip->bios_dir = tpm_bios_log_setup(chip->devname); + + return 0; +} + +static void tpm1_chip_unregister(struct tpm_chip *chip) +{ + if (chip->flags & TPM_CHIP_FLAG_TPM2) + return; + + if (chip->bios_dir) + tpm_bios_log_teardown(chip->bios_dir); + + tpm_remove_ppi(chip); + + tpm_sysfs_del_device(chip); +} + /* * tpm_chip_register() - create a character device for the TPM chip * @chip: TPM chip to use. @@ -185,22 +220,13 @@ int tpm_chip_register(struct tpm_chip *chip) { int rc; - /* Populate sysfs for TPM1 devices. */ - if (!(chip->flags & TPM_CHIP_FLAG_TPM2)) { - rc = tpm_sysfs_add_device(chip); - if (rc) - goto del_misc; - - rc = tpm_add_ppi(chip); - if (rc) - goto del_sysfs; - - chip->bios_dir = tpm_bios_log_setup(chip->devname); - } + rc = tpm1_chip_register(chip); + if (rc) + return rc; rc = tpm_dev_add_device(chip); if (rc) - return rc; + goto out_err; /* Make the chip available. */ spin_lock(&driver_lock); @@ -210,10 +236,8 @@ int tpm_chip_register(struct tpm_chip *chip) chip->flags |= TPM_CHIP_FLAG_REGISTERED; return 0; -del_sysfs: - tpm_sysfs_del_device(chip); -del_misc: - tpm_dev_del_device(chip); +out_err: + tpm1_chip_unregister(chip); return rc; } EXPORT_SYMBOL_GPL(tpm_chip_register); @@ -238,13 +262,7 @@ void tpm_chip_unregister(struct tpm_chip *chip) spin_unlock(&driver_lock); synchronize_rcu(); - if (!(chip->flags & TPM_CHIP_FLAG_TPM2)) { - if (chip->bios_dir) - tpm_bios_log_teardown(chip->bios_dir); - tpm_remove_ppi(chip); - tpm_sysfs_del_device(chip); - } - + tpm1_chip_unregister(chip); tpm_dev_del_device(chip); } EXPORT_SYMBOL_GPL(tpm_chip_unregister); -- 2.1.4