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tpm_tis: Fix check_locality for correct locality acquisition

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commit 3d9ae54af1 upstream.

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: 27084efee0 ("[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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
James Bottomley 2020-10-01 11:09:21 -07:00 • committed by Greg Kroah-Hartman
commit a1710b067e
1 changed files with 2 additions and 1 deletions
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3
drivers/char/tpm/tpm_tis_core.c
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@ -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;