linux-kernel - [PATCH AUTOSEL 4.19 106/146] tpm: suppress transmit cmd error logs when TPM 1.2 is disabled/deactivated

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20181031230541.28822-106-sashal@kernel.org>
Date:   Wed, 31 Oct 2018 19:05:01 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     stable@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Javier Martinez Canillas <javierm@...hat.com>,
        Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH AUTOSEL 4.19 106/146] tpm: suppress transmit cmd error logs when TPM 1.2 is disabled/deactivated

From: Javier Martinez Canillas <javierm@...hat.com>

[ Upstream commit 0d6d0d62d9505a9816716aa484ebd0b04c795063 ]

For TPM 1.2 chips the system setup utility allows to set the TPM device in
one of the following states:

  * Active: Security chip is functional
  * Inactive: Security chip is visible, but is not functional
  * Disabled: Security chip is hidden and is not functional

When choosing the "Inactive" state, the TPM 1.2 device is enumerated and
registered, but sending TPM commands fail with either TPM_DEACTIVATED or
TPM_DISABLED depending if the firmware deactivated or disabled the TPM.

Since these TPM 1.2 error codes don't have special treatment, inactivating
the TPM leads to a very noisy kernel log buffer that shows messages like
the following:

  tpm_tis 00:05: 1.2 TPM (device-id 0x0, rev-id 78)
  tpm tpm0: A TPM error (6) occurred attempting to read a pcr value
  tpm tpm0: TPM is disabled/deactivated (0x6)
  tpm tpm0: A TPM error (6) occurred attempting get random
  tpm tpm0: A TPM error (6) occurred attempting to read a pcr value
  ima: No TPM chip found, activating TPM-bypass! (rc=6)
  tpm tpm0: A TPM error (6) occurred attempting get random
  tpm tpm0: A TPM error (6) occurred attempting get random
  tpm tpm0: A TPM error (6) occurred attempting get random
  tpm tpm0: A TPM error (6) occurred attempting get random

Let's just suppress error log messages for the TPM_{DEACTIVATED,DISABLED}
return codes, since this is expected when the TPM 1.2 is set to Inactive.

In that case the kernel log is cleaner and less confusing for users, i.e:

  tpm_tis 00:05: 1.2 TPM (device-id 0x0, rev-id 78)
  tpm tpm0: TPM is disabled/deactivated (0x6)
  ima: No TPM chip found, activating TPM-bypass! (rc=6)

Reported-by: Hans de Goede <hdegoede@...hat.com>
Signed-off-by: Javier Martinez Canillas <javierm@...hat.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/char/tpm/tpm-interface.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 1a803b0cf980..9f61106502a9 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -663,7 +663,8 @@ ssize_t tpm_transmit_cmd(struct tpm_chip *chip, struct tpm_space *space,
 		return len;

 	err = be32_to_cpu(header->return_code);
-	if (err != 0 && desc)
+	if (err != 0 && err != TPM_ERR_DISABLED && err != TPM_ERR_DEACTIVATED
+	    && desc)
 		dev_err(&chip->dev, "A TPM error (%d) occurred %s\n", err,
 			desc);
 	if (err)
-- 
2.17.1