[PATCH v4] KEYS: trusted: correctly initialize digests and fix locking issue

From: Roberto Sassu
Date: Fri Sep 13 2019 - 14:52:04 EST


Commit 0b6cf6b97b7e ("tpm: pass an array of tpm_extend_digest structures to
tpm_pcr_extend()") modifies tpm_pcr_extend() to accept a digest for each
PCR bank. After modification, tpm_pcr_extend() expects that digests are
passed in the same order as the algorithms set in chip->allocated_banks.

This patch fixes two issues introduced in the last iterations of the patch
set: missing initialization of the TPM algorithm ID in the tpm_digest
structures passed to tpm_pcr_extend() by the trusted key module, and
unreleased locks in the TPM driver due to returning from tpm_pcr_extend()
without calling tpm_put_ops().

Signed-off-by: Roberto Sassu <roberto.sassu@xxxxxxxxxx>
Suggested-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
Reviewed-by: Jerry Snitselaar <jsnitsel@xxxxxxxxxx>
Fixes: 0b6cf6b97b7e ("tpm: pass an array of tpm_extend_digest structures to tpm_pcr_extend()")
---
drivers/char/tpm/tpm-interface.c | 14 +++++++++-----
security/keys/trusted.c | 5 +++++
2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 1b4f95c13e00..d9ace5480665 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -320,18 +320,22 @@ int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
if (!chip)
return -ENODEV;

- for (i = 0; i < chip->nr_allocated_banks; i++)
- if (digests[i].alg_id != chip->allocated_banks[i].alg_id)
- return -EINVAL;
+ for (i = 0; i < chip->nr_allocated_banks; i++) {
+ if (digests[i].alg_id != chip->allocated_banks[i].alg_id) {
+ rc = EINVAL;
+ goto out;
+ }
+ }

if (chip->flags & TPM_CHIP_FLAG_TPM2) {
rc = tpm2_pcr_extend(chip, pcr_idx, digests);
- tpm_put_ops(chip);
- return rc;
+ goto out;
}

rc = tpm1_pcr_extend(chip, pcr_idx, digests[0].digest,
"attempting extend a PCR value");
+
+out:
tpm_put_ops(chip);
return rc;
}
diff --git a/security/keys/trusted.c b/security/keys/trusted.c
index ade699131065..1fbd77816610 100644
--- a/security/keys/trusted.c
+++ b/security/keys/trusted.c
@@ -1228,11 +1228,16 @@ static int __init trusted_shash_alloc(void)

static int __init init_digests(void)
{
+ int i;
+
digests = kcalloc(chip->nr_allocated_banks, sizeof(*digests),
GFP_KERNEL);
if (!digests)
return -ENOMEM;

+ for (i = 0; i < chip->nr_allocated_banks; i++)
+ digests[i].alg_id = chip->allocated_banks[i].alg_id;
+
return 0;
}

--
2.17.1