KEYS: trusted: Reserve TPM for seal and unseal operations

When TPM 2.0 trusted keys code was moved to the trusted keys subsystem,
the operations were unwrapped from tpm_try_get_ops() and tpm_put_ops(),
which are used to take temporarily the ownership of the TPM chip. The
ownership is only taken inside tpm_send(), but this is not sufficient,
as in the key load TPM2_CC_LOAD, TPM2_CC_UNSEAL and TPM2_FLUSH_CONTEXT
need to be done as a one single atom.

Take the TPM chip ownership before sending anything with
tpm_try_get_ops() and tpm_put_ops(), and use tpm_transmit_cmd() to send
TPM commands instead of tpm_send(), reverting back to the old behaviour.

Fixes: 2e19e10131a0 ("KEYS: trusted: Move TPM2 trusted keys code")
Reported-by: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: stable@vger.kernel.org
Cc: David Howells <dhowells@redhat.com>
Cc: Mimi Zohar <zohar@linux.ibm.com>
Cc: Sumit Garg <sumit.garg@linaro.org>
Acked-by Sumit Garg <sumit.garg@linaro.org>
Tested-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>

1 files changed, 18 insertions, 4 deletions

diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c
index 08ec7f48f01d..e2a0ed5d02f0 100644
--- a/security/keys/trusted-keys/trusted_tpm2.c
+++ b/security/keys/trusted-keys/trusted_tpm2.c
@@ -83,6 +83,12 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
 	if (rc)
 		return rc;
 
+	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_CREATE);
+	if (rc) {
+		tpm_put_ops(chip);
+		return rc;
+	}
+
 	tpm_buf_append_u32(&buf, options->keyhandle);
 	tpm2_buf_append_auth(&buf, TPM2_RS_PW,
 			     NULL /* nonce */, 0,
@@ -130,7 +136,7 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
 		goto out;
 	}
 
-	rc = tpm_send(chip, buf.data, tpm_buf_length(&buf));
+	rc = tpm_transmit_cmd(chip, &buf, 4, "sealing data");
 	if (rc)
 		goto out;
 
@@ -157,6 +163,7 @@ out:
 			rc = -EPERM;
 	}
 
+	tpm_put_ops(chip);
 	return rc;
 }
 
@@ -211,7 +218,7 @@ static int tpm2_load_cmd(struct tpm_chip *chip,
 		goto out;
 	}
 
-	rc = tpm_send(chip, buf.data, tpm_buf_length(&buf));
+	rc = tpm_transmit_cmd(chip, &buf, 4, "loading blob");
 	if (!rc)
 		*blob_handle = be32_to_cpup(
 			(__be32 *) &buf.data[TPM_HEADER_SIZE]);
@@ -260,7 +267,7 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
 			     options->blobauth /* hmac */,
 			     TPM_DIGEST_SIZE);
 
-	rc = tpm_send(chip, buf.data, tpm_buf_length(&buf));
+	rc = tpm_transmit_cmd(chip, &buf, 6, "unsealing");
 	if (rc > 0)
 		rc = -EPERM;
 
@@ -304,12 +311,19 @@ int tpm2_unseal_trusted(struct tpm_chip *chip,
 	u32 blob_handle;
 	int rc;
 
-	rc = tpm2_load_cmd(chip, payload, options, &blob_handle);
+	rc = tpm_try_get_ops(chip);
 	if (rc)
 		return rc;
 
+	rc = tpm2_load_cmd(chip, payload, options, &blob_handle);
+	if (rc)
+		goto out;
+
 	rc = tpm2_unseal_cmd(chip, payload, options, blob_handle);
 	tpm2_flush_context(chip, blob_handle);
 
+out:
+	tpm_put_ops(chip);
+
 	return rc;
 }