linux-kernel - [PATCH 5.2 10/61] tpm: Fix TPM 1.2 Shutdown sequence to prevent future TPM operations

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Date:   Fri, 12 Jul 2019 14:19:23 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Vadim Sukhomlinov <sukhomlinov@...gle.com>,
        Douglas Anderson <dianders@...omium.org>,
        Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
Subject: [PATCH 5.2 10/61] tpm: Fix TPM 1.2 Shutdown sequence to prevent future TPM operations

From: Vadim Sukhomlinov <sukhomlinov@...gle.com>

commit db4d8cb9c9f2af71c4d087817160d866ed572cc9 upstream.

TPM 2.0 Shutdown involve sending TPM2_Shutdown to TPM chip and disabling
future TPM operations. TPM 1.2 behavior was different, future TPM
operations weren't disabled, causing rare issues. This patch ensures
that future TPM operations are disabled.

Fixes: d1bd4a792d39 ("tpm: Issue a TPM2_Shutdown for TPM2 devices.")
Cc: stable@...r.kernel.org
Signed-off-by: Vadim Sukhomlinov <sukhomlinov@...gle.com>
[dianders: resolved merge conflicts with mainline]
Signed-off-by: Douglas Anderson <dianders@...omium.org>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/char/tpm/tpm-chip.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -289,15 +289,15 @@ static int tpm_class_shutdown(struct dev
 {
 	struct tpm_chip *chip = container_of(dev, struct tpm_chip, dev);
 
+	down_write(&chip->ops_sem);
 	if (chip->flags & TPM_CHIP_FLAG_TPM2) {
-		down_write(&chip->ops_sem);
 		if (!tpm_chip_start(chip)) {
 			tpm2_shutdown(chip, TPM2_SU_CLEAR);
 			tpm_chip_stop(chip);
 		}
-		chip->ops = NULL;
-		up_write(&chip->ops_sem);
 	}
+	chip->ops = NULL;
+	up_write(&chip->ops_sem);
 
 	return 0;
 }