Commit 8c657a05 authored by Jarkko Sakkinen's avatar Jarkko Sakkinen
Browse files

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: 2e19e101 ("KEYS: trusted: Move TPM2 trusted keys code")
Reported-by: default avatar"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: default avatarMimi Zohar <zohar@linux.ibm.com>
Signed-off-by: default avatarJarkko Sakkinen <jarkko@kernel.org>
parent 8da7520c

drivers/char/tpm/tpm.h

+0 −4
Original line number Diff line number Diff line
@@ -164,8 +164,6 @@ extern const struct file_operations tpmrm_fops; 
extern struct idr dev_nums_idr;



ssize_t tpm_transmit(struct tpm_chip *chip, u8 *buf, size_t bufsiz);

ssize_t tpm_transmit_cmd(struct tpm_chip *chip, struct tpm_buf *buf,

			 size_t min_rsp_body_length, const char *desc);

int tpm_get_timeouts(struct tpm_chip *);

int tpm_auto_startup(struct tpm_chip *chip);
@@ -194,8 +192,6 @@ static inline void tpm_msleep(unsigned int delay_msec) 
int tpm_chip_start(struct tpm_chip *chip);

void tpm_chip_stop(struct tpm_chip *chip);

struct tpm_chip *tpm_find_get_ops(struct tpm_chip *chip);

__must_check int tpm_try_get_ops(struct tpm_chip *chip);

void tpm_put_ops(struct tpm_chip *chip);



struct tpm_chip *tpm_chip_alloc(struct device *dev,

				const struct tpm_class_ops *ops);

include/linux/tpm.h

+4 −1
Original line number Diff line number Diff line
@@ -404,6 +404,10 @@ static inline u32 tpm2_rc_value(u32 rc) 
#if defined(CONFIG_TCG_TPM) || defined(CONFIG_TCG_TPM_MODULE)



extern int tpm_is_tpm2(struct tpm_chip *chip);

extern __must_check int tpm_try_get_ops(struct tpm_chip *chip);

extern void tpm_put_ops(struct tpm_chip *chip);

extern ssize_t tpm_transmit_cmd(struct tpm_chip *chip, struct tpm_buf *buf,

				size_t min_rsp_body_length, const char *desc);

extern int tpm_pcr_read(struct tpm_chip *chip, u32 pcr_idx,

			struct tpm_digest *digest);

extern int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
@@ -417,7 +421,6 @@ static inline int tpm_is_tpm2(struct tpm_chip *chip) 
{

	return -ENODEV;

}



static inline int tpm_pcr_read(struct tpm_chip *chip, int pcr_idx,

			       struct tpm_digest *digest)

{

security/keys/trusted-keys/trusted_tpm2.c

+18 −4
Original line number Diff line number Diff line
@@ -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 @@ int tpm2_seal_trusted(struct tpm_chip *chip, 
			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;

}