From 34d47b6322087665be33ca3aa81775b143a4d7ac Mon Sep 17 00:00:00 2001 From: Jarkko Sakkinen Date: Wed, 18 Mar 2015 08:17:14 +0200 Subject: [PATCH] tpm: fix: sanitized code paths in tpm_chip_register() 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. Cc: Fixes: 7a1d7e6dd76a ("tpm: TPM 2.0 baseline support") Signed-off-by: Jarkko Sakkinen Tested-by: Scot Doyle Reviewed-by: Peter Huewe Signed-off-by: Peter Huewe --- 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 e096e9cddb40..283f00a7f036 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); -- 2.20.1