From b39914384da5469bef5323ba67543d61d6360773 Mon Sep 17 00:00:00 2001
From: Vadim Sukhomlinov <sukhomlinov@google.com>
Date: Mon, 10 Jun 2019 15:01:18 -0700
Subject: [PATCH 1/1] tpm: Fix TPM 1.2 Shutdown sequence to prevent future TPM
 operations

References: bsc#1082555
Patch-mainline: v5.3-rc1
Git-commit: db4d8cb9c9f2af71c4d087817160d866ed572cc9

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@vger.kernel.org
Signed-off-by: Vadim Sukhomlinov <sukhomlinov@google.com>
[dianders: resolved merge conflicts with mainline]
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
 drivers/char/tpm/tpm-chip.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 67ec9d3d04f5..5ed5d9174994 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -158,12 +158,12 @@ static int tpm_class_shutdown(struct device *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);
 		tpm2_shutdown(chip, TPM2_SU_CLEAR);
-		chip->ops = NULL;
-		up_write(&chip->ops_sem);
 	}
+	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.
-- 
2.22.0