From 3d9ae54af1d02a7c0edc55c77d7df2b921e58a87 Mon Sep 17 00:00:00 2001
From: James Bottomley <James.Bottomley@HansenPartnership.com>
Date: Thu, 1 Oct 2020 11:09:21 -0700
Subject: [PATCH] tpm_tis: Fix check_locality for correct locality acquisition
Git-commit: 3d9ae54af1d02a7c0edc55c77d7df2b921e58a87
Patch-mainline: v5.12-rc1
References: git-fixes

The TPM TIS specification says the TPM signals the acquisition of locality
when the TMP_ACCESS_REQUEST_USE bit goes to one *and* the
TPM_ACCESS_REQUEST_USE bit goes to zero.  Currently we only check the
former not the latter, so check both.  Adding the check on
TPM_ACCESS_REQUEST_USE should fix the case where the locality is
re-requested before the TPM has released it.  In this case the locality may
get released briefly before it is reacquired, which causes all sorts of
problems. However, with the added check, TPM_ACCESS_REQUEST_USE should
remain 1 until the second request for the locality is granted.

Cc: stable@ger.kernel.org
Fixes: 27084efee0c3 ("[PATCH] tpm: driver for next generation TPM chips")
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/char/tpm/tpm_tis_core.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index 92c51c6cfd1b..f3ecde8df47d 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -125,7 +125,8 @@ static bool check_locality(struct tpm_chip *chip, int l)
 	if (rc < 0)
 		return false;
 
-	if ((access & (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) ==
+	if ((access & (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID
+		       | TPM_ACCESS_REQUEST_USE)) ==
 	    (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) {
 		priv->locality = l;
 		return true;
-- 
2.26.2