diff mbox series

[v3,08/16] tpm: move tpm_validate_commmand() to tpm2-space.c

Message ID 20181105014552.20262-9-jarkko.sakkinen@linux.intel.com (mailing list archive)
State New, archived
Headers show
Series Remove nested TPM operations | expand

Commit Message

Jarkko Sakkinen Nov. 5, 2018, 1:45 a.m. UTC
Move tpm_validate_command() to tpm2-space.c and make it part of the
tpm2_prepare_space() flow. Make cc resolution as part of the TPM space
functionality in order to detach it from rest of the tpm_transmit()
flow.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 drivers/char/tpm/tpm-interface.c | 72 +++++++-------------------------
 drivers/char/tpm/tpm.h           |  9 ++--
 drivers/char/tpm/tpm2-space.c    | 54 +++++++++++++++++++++---
 3 files changed, 68 insertions(+), 67 deletions(-)

Comments

Stefan Berger Nov. 5, 2018, 10:36 p.m. UTC | #1
On 11/4/18 8:45 PM, Jarkko Sakkinen wrote:
> Move tpm_validate_command() to tpm2-space.c and make it part of the
> tpm2_prepare_space() flow. Make cc resolution as part of the TPM space
> functionality in order to detach it from rest of the tpm_transmit()
> flow.
>
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> ---
>   drivers/char/tpm/tpm-interface.c | 72 +++++++-------------------------
>   drivers/char/tpm/tpm.h           |  9 ++--
>   drivers/char/tpm/tpm2-space.c    | 54 +++++++++++++++++++++---
>   3 files changed, 68 insertions(+), 67 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> index 422e3bb0bd3d..3bf0c51b7b4f 100644
> --- a/drivers/char/tpm/tpm-interface.c
> +++ b/drivers/char/tpm/tpm-interface.c
> @@ -62,47 +62,6 @@ unsigned long tpm_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal)
>   }
>   EXPORT_SYMBOL_GPL(tpm_calc_ordinal_duration);
>
> -static int tpm_validate_command(struct tpm_chip *chip,
> -				 struct tpm_space *space,
> -				 const u8 *cmd,
> -				 size_t len)
> -{
> -	const struct tpm_input_header *header = (const void *)cmd;
> -	int i;
> -	u32 cc;
> -	u32 attrs;
> -	unsigned int nr_handles;
> -
> -	if (len < TPM_HEADER_SIZE)
> -		return -EINVAL;
> -
> -	if (!space)
> -		return 0;
> -
> -	if (chip->flags & TPM_CHIP_FLAG_TPM2 && chip->nr_commands) {
> -		cc = be32_to_cpu(header->ordinal);
> -
> -		i = tpm2_find_cc(chip, cc);
> -		if (i < 0) {
> -			dev_dbg(&chip->dev, "0x%04X is an invalid command\n",
> -				cc);
> -			return -EOPNOTSUPP;
> -		}
> -
> -		attrs = chip->cc_attrs_tbl[i];
> -		nr_handles =
> -			4 * ((attrs >> TPM2_CC_ATTR_CHANDLES) & GENMASK(2, 0));
> -		if (len < TPM_HEADER_SIZE + 4 * nr_handles)
> -			goto err_len;
> -	}
> -
> -	return 0;
> -err_len:
> -	dev_dbg(&chip->dev,
> -		"%s: insufficient command length %zu", __func__, len);
> -	return -EINVAL;
> -}
> -
>   static int tpm_request_locality(struct tpm_chip *chip, unsigned int flags)
>   {
>   	int rc;
> @@ -172,20 +131,8 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip,
>   	u32 count, ordinal;
>   	unsigned long stop;
>
> -	rc = tpm_validate_command(chip, space, buf, bufsiz);
> -	if (rc == -EINVAL)
> -		return rc;
> -	/*
> -	 * If the command is not implemented by the TPM, synthesize a
> -	 * response with a TPM2_RC_COMMAND_CODE return for user-space.
> -	 */
> -	if (rc == -EOPNOTSUPP) {
> -		header->length = cpu_to_be32(sizeof(*header));
> -		header->tag = cpu_to_be16(TPM2_ST_NO_SESSIONS);
> -		header->return_code = cpu_to_be32(TPM2_RC_COMMAND_CODE |
> -						  TSS2_RESMGR_TPM_RC_LAYER);
> -		return sizeof(*header);
> -	}
> +	if (bufsiz < TPM_HEADER_SIZE)
> +		return -EINVAL;
>
>   	if (bufsiz > TPM_BUFSIZE)
>   		bufsiz = TPM_BUFSIZE;
> @@ -200,7 +147,18 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip,
>   		return -E2BIG;
>   	}
>
> -	rc = tpm2_prepare_space(chip, space, ordinal, buf);
> +	rc = tpm2_prepare_space(chip, space, buf, bufsiz);
> +	/*
> +	 * If the command is not implemented by the TPM, synthesize a
> +	 * response with a TPM2_RC_COMMAND_CODE return for user-space.
> +	 */
> +	if (rc == -EOPNOTSUPP) {
> +		header->length = cpu_to_be32(sizeof(*header));
> +		header->tag = cpu_to_be16(TPM2_ST_NO_SESSIONS);
> +		header->return_code = cpu_to_be32(TPM2_RC_COMMAND_CODE |
> +						  TSS2_RESMGR_TPM_RC_LAYER);
> +		return sizeof(*header);
> +	}
>   	if (rc)
>   		return rc;
>
> @@ -251,7 +209,7 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip,
>   	if (rc)
>   		tpm2_flush_space(chip);
>   	else
> -		rc = tpm2_commit_space(chip, space, ordinal, buf, &len);
> +		rc = tpm2_commit_space(chip, space, buf, &len);
>
>   	return rc ? rc : len;
>   }
> diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
> index 229ac42b644e..8503dd261897 100644
> --- a/drivers/char/tpm/tpm.h
> +++ b/drivers/char/tpm/tpm.h
> @@ -264,6 +264,7 @@ struct tpm_chip {
>   #endif /* CONFIG_ACPI */
>
>   	struct tpm_space work_space;
> +	u32 last_cc;
>   	u32 nr_commands;
>   	u32 *cc_attrs_tbl;
>
> @@ -580,10 +581,10 @@ int tpm2_find_cc(struct tpm_chip *chip, u32 cc);
>   int tpm2_init_space(struct tpm_space *space);
>   void tpm2_del_space(struct tpm_chip *chip, struct tpm_space *space);
>   void tpm2_flush_space(struct tpm_chip *chip);
> -int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u32 cc,
> -		       u8 *cmd);
> -int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space,
> -		      u32 cc, u8 *buf, size_t *bufsiz);
> +int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u8 *cmd,
> +		       size_t cmdsiz);
> +int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space, u8 *buf,
> +		       size_t *bufsiz);
>
>   int tpm_bios_log_setup(struct tpm_chip *chip);
>   void tpm_bios_log_teardown(struct tpm_chip *chip);
> diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
> index 3d5f9577e5de..20c295fadd50 100644
> --- a/drivers/char/tpm/tpm2-space.c
> +++ b/drivers/char/tpm/tpm2-space.c
> @@ -264,14 +264,55 @@ static int tpm2_map_command(struct tpm_chip *chip, u32 cc, u8 *cmd)
>   	return 0;
>   }
>
> -int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u32 cc,
> -		       u8 *cmd)
> +static int tpm_validate_command(struct tpm_chip *chip, struct tpm_space *space,
> +				const u8 *cmd, size_t len)


Nit: len -> cmdsiz (like below)


> +{
> +	const struct tpm_input_header *header = (const void *)cmd;
> +	int i;
> +	u32 cc;
> +	u32 attrs;
> +	unsigned int nr_handles;
> +
> +	if (len < TPM_HEADER_SIZE)
> +		return -EINVAL;
> +
> +	if (chip->nr_commands) {
> +		cc = be32_to_cpu(header->ordinal);
> +
> +		i = tpm2_find_cc(chip, cc);
> +		if (i < 0) {
> +			dev_dbg(&chip->dev, "0x%04X is an invalid command\n",
> +				cc);
> +			return -EOPNOTSUPP;
> +		}
> +
> +		attrs = chip->cc_attrs_tbl[i];
> +		nr_handles =
> +			4 * ((attrs >> TPM2_CC_ATTR_CHANDLES) & GENMASK(2, 0));
> +		if (len < TPM_HEADER_SIZE + 4 * nr_handles)
> +			goto err_len;
> +	}
> +
> +	return cc;
> +err_len:
> +	dev_dbg(&chip->dev, "%s: insufficient command length %zu", __func__,
> +		len);
> +	return -EINVAL;
> +}
> +
> +int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u8 *cmd,
> +		       size_t cmdsiz)
>   {
>   	int rc;
> +	int cc;
>
>   	if (!space)
>   		return 0;
>
> +	cc = tpm_validate_command(chip, space, cmd, cmdsiz);
> +	if (cc < 0)
> +		return cc;
> +
>   	memcpy(&chip->work_space.context_tbl, &space->context_tbl,
>   	       sizeof(space->context_tbl));
>   	memcpy(&chip->work_space.session_tbl, &space->session_tbl,
> @@ -291,6 +332,7 @@ int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u32 cc,
>   		return rc;
>   	}
>
> +	chip->last_cc = cc;
>   	return 0;
>   }
>
> @@ -489,8 +531,8 @@ static int tpm2_save_space(struct tpm_chip *chip)
>   	return 0;
>   }
>
> -int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space,
> -		      u32 cc, u8 *buf, size_t *bufsiz)
> +int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space, u8 *buf,
> +		      size_t *bufsiz)
>   {
>   	struct tpm_output_header *header = (void *)buf;
>   	int rc;
> @@ -498,13 +540,13 @@ int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space,
>   	if (!space)
>   		return 0;
>
> -	rc = tpm2_map_response_header(chip, cc, buf, *bufsiz);
> +	rc = tpm2_map_response_header(chip, chip->last_cc, buf, *bufsiz);
>   	if (rc) {
>   		tpm2_flush_space(chip);
>   		goto out;
>   	}
>
> -	rc = tpm2_map_response_body(chip, cc, buf, *bufsiz);
> +	rc = tpm2_map_response_body(chip, chip->last_cc, buf, *bufsiz);
>   	if (rc) {
>   		tpm2_flush_space(chip);
>   		goto out;

Rest looks good.

Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Jarkko Sakkinen Nov. 6, 2018, 6:10 a.m. UTC | #2
On Mon, Nov 05, 2018 at 05:36:03PM -0500, Stefan Berger wrote:
> On 11/4/18 8:45 PM, Jarkko Sakkinen wrote:
> > Move tpm_validate_command() to tpm2-space.c and make it part of the
> > tpm2_prepare_space() flow. Make cc resolution as part of the TPM space
> > functionality in order to detach it from rest of the tpm_transmit()
> > flow.
> > 
> > Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> > ---
> >   drivers/char/tpm/tpm-interface.c | 72 +++++++-------------------------
> >   drivers/char/tpm/tpm.h           |  9 ++--
> >   drivers/char/tpm/tpm2-space.c    | 54 +++++++++++++++++++++---
> >   3 files changed, 68 insertions(+), 67 deletions(-)
> > 
> > diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> > index 422e3bb0bd3d..3bf0c51b7b4f 100644
> > --- a/drivers/char/tpm/tpm-interface.c
> > +++ b/drivers/char/tpm/tpm-interface.c
> > @@ -62,47 +62,6 @@ unsigned long tpm_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal)
> >   }
> >   EXPORT_SYMBOL_GPL(tpm_calc_ordinal_duration);
> > 
> > -static int tpm_validate_command(struct tpm_chip *chip,
> > -				 struct tpm_space *space,
> > -				 const u8 *cmd,
> > -				 size_t len)
> > -{
> > -	const struct tpm_input_header *header = (const void *)cmd;
> > -	int i;
> > -	u32 cc;
> > -	u32 attrs;
> > -	unsigned int nr_handles;
> > -
> > -	if (len < TPM_HEADER_SIZE)
> > -		return -EINVAL;
> > -
> > -	if (!space)
> > -		return 0;
> > -
> > -	if (chip->flags & TPM_CHIP_FLAG_TPM2 && chip->nr_commands) {
> > -		cc = be32_to_cpu(header->ordinal);
> > -
> > -		i = tpm2_find_cc(chip, cc);
> > -		if (i < 0) {
> > -			dev_dbg(&chip->dev, "0x%04X is an invalid command\n",
> > -				cc);
> > -			return -EOPNOTSUPP;
> > -		}
> > -
> > -		attrs = chip->cc_attrs_tbl[i];
> > -		nr_handles =
> > -			4 * ((attrs >> TPM2_CC_ATTR_CHANDLES) & GENMASK(2, 0));
> > -		if (len < TPM_HEADER_SIZE + 4 * nr_handles)
> > -			goto err_len;
> > -	}
> > -
> > -	return 0;
> > -err_len:
> > -	dev_dbg(&chip->dev,
> > -		"%s: insufficient command length %zu", __func__, len);
> > -	return -EINVAL;
> > -}
> > -
> >   static int tpm_request_locality(struct tpm_chip *chip, unsigned int flags)
> >   {
> >   	int rc;
> > @@ -172,20 +131,8 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip,
> >   	u32 count, ordinal;
> >   	unsigned long stop;
> > 
> > -	rc = tpm_validate_command(chip, space, buf, bufsiz);
> > -	if (rc == -EINVAL)
> > -		return rc;
> > -	/*
> > -	 * If the command is not implemented by the TPM, synthesize a
> > -	 * response with a TPM2_RC_COMMAND_CODE return for user-space.
> > -	 */
> > -	if (rc == -EOPNOTSUPP) {
> > -		header->length = cpu_to_be32(sizeof(*header));
> > -		header->tag = cpu_to_be16(TPM2_ST_NO_SESSIONS);
> > -		header->return_code = cpu_to_be32(TPM2_RC_COMMAND_CODE |
> > -						  TSS2_RESMGR_TPM_RC_LAYER);
> > -		return sizeof(*header);
> > -	}
> > +	if (bufsiz < TPM_HEADER_SIZE)
> > +		return -EINVAL;
> > 
> >   	if (bufsiz > TPM_BUFSIZE)
> >   		bufsiz = TPM_BUFSIZE;
> > @@ -200,7 +147,18 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip,
> >   		return -E2BIG;
> >   	}
> > 
> > -	rc = tpm2_prepare_space(chip, space, ordinal, buf);
> > +	rc = tpm2_prepare_space(chip, space, buf, bufsiz);
> > +	/*
> > +	 * If the command is not implemented by the TPM, synthesize a
> > +	 * response with a TPM2_RC_COMMAND_CODE return for user-space.
> > +	 */
> > +	if (rc == -EOPNOTSUPP) {
> > +		header->length = cpu_to_be32(sizeof(*header));
> > +		header->tag = cpu_to_be16(TPM2_ST_NO_SESSIONS);
> > +		header->return_code = cpu_to_be32(TPM2_RC_COMMAND_CODE |
> > +						  TSS2_RESMGR_TPM_RC_LAYER);
> > +		return sizeof(*header);
> > +	}
> >   	if (rc)
> >   		return rc;
> > 
> > @@ -251,7 +209,7 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip,
> >   	if (rc)
> >   		tpm2_flush_space(chip);
> >   	else
> > -		rc = tpm2_commit_space(chip, space, ordinal, buf, &len);
> > +		rc = tpm2_commit_space(chip, space, buf, &len);
> > 
> >   	return rc ? rc : len;
> >   }
> > diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
> > index 229ac42b644e..8503dd261897 100644
> > --- a/drivers/char/tpm/tpm.h
> > +++ b/drivers/char/tpm/tpm.h
> > @@ -264,6 +264,7 @@ struct tpm_chip {
> >   #endif /* CONFIG_ACPI */
> > 
> >   	struct tpm_space work_space;
> > +	u32 last_cc;
> >   	u32 nr_commands;
> >   	u32 *cc_attrs_tbl;
> > 
> > @@ -580,10 +581,10 @@ int tpm2_find_cc(struct tpm_chip *chip, u32 cc);
> >   int tpm2_init_space(struct tpm_space *space);
> >   void tpm2_del_space(struct tpm_chip *chip, struct tpm_space *space);
> >   void tpm2_flush_space(struct tpm_chip *chip);
> > -int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u32 cc,
> > -		       u8 *cmd);
> > -int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space,
> > -		      u32 cc, u8 *buf, size_t *bufsiz);
> > +int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u8 *cmd,
> > +		       size_t cmdsiz);
> > +int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space, u8 *buf,
> > +		       size_t *bufsiz);
> > 
> >   int tpm_bios_log_setup(struct tpm_chip *chip);
> >   void tpm_bios_log_teardown(struct tpm_chip *chip);
> > diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
> > index 3d5f9577e5de..20c295fadd50 100644
> > --- a/drivers/char/tpm/tpm2-space.c
> > +++ b/drivers/char/tpm/tpm2-space.c
> > @@ -264,14 +264,55 @@ static int tpm2_map_command(struct tpm_chip *chip, u32 cc, u8 *cmd)
> >   	return 0;
> >   }
> > 
> > -int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u32 cc,
> > -		       u8 *cmd)
> > +static int tpm_validate_command(struct tpm_chip *chip, struct tpm_space *space,
> > +				const u8 *cmd, size_t len)
> 
> 
> Nit: len -> cmdsiz (like below)
> 
> 
> > +{
> > +	const struct tpm_input_header *header = (const void *)cmd;
> > +	int i;
> > +	u32 cc;
> > +	u32 attrs;
> > +	unsigned int nr_handles;
> > +
> > +	if (len < TPM_HEADER_SIZE)
> > +		return -EINVAL;
> > +
> > +	if (chip->nr_commands) {
> > +		cc = be32_to_cpu(header->ordinal);
> > +
> > +		i = tpm2_find_cc(chip, cc);
> > +		if (i < 0) {
> > +			dev_dbg(&chip->dev, "0x%04X is an invalid command\n",
> > +				cc);
> > +			return -EOPNOTSUPP;
> > +		}
> > +
> > +		attrs = chip->cc_attrs_tbl[i];
> > +		nr_handles =
> > +			4 * ((attrs >> TPM2_CC_ATTR_CHANDLES) & GENMASK(2, 0));
> > +		if (len < TPM_HEADER_SIZE + 4 * nr_handles)
> > +			goto err_len;
> > +	}
> > +
> > +	return cc;
> > +err_len:
> > +	dev_dbg(&chip->dev, "%s: insufficient command length %zu", __func__,
> > +		len);
> > +	return -EINVAL;
> > +}
> > +
> > +int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u8 *cmd,
> > +		       size_t cmdsiz)
> >   {
> >   	int rc;
> > +	int cc;
> > 
> >   	if (!space)
> >   		return 0;
> > 
> > +	cc = tpm_validate_command(chip, space, cmd, cmdsiz);
> > +	if (cc < 0)
> > +		return cc;
> > +
> >   	memcpy(&chip->work_space.context_tbl, &space->context_tbl,
> >   	       sizeof(space->context_tbl));
> >   	memcpy(&chip->work_space.session_tbl, &space->session_tbl,
> > @@ -291,6 +332,7 @@ int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u32 cc,
> >   		return rc;
> >   	}
> > 
> > +	chip->last_cc = cc;
> >   	return 0;
> >   }
> > 
> > @@ -489,8 +531,8 @@ static int tpm2_save_space(struct tpm_chip *chip)
> >   	return 0;
> >   }
> > 
> > -int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space,
> > -		      u32 cc, u8 *buf, size_t *bufsiz)
> > +int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space, u8 *buf,
> > +		      size_t *bufsiz)
> >   {
> >   	struct tpm_output_header *header = (void *)buf;
> >   	int rc;
> > @@ -498,13 +540,13 @@ int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space,
> >   	if (!space)
> >   		return 0;
> > 
> > -	rc = tpm2_map_response_header(chip, cc, buf, *bufsiz);
> > +	rc = tpm2_map_response_header(chip, chip->last_cc, buf, *bufsiz);
> >   	if (rc) {
> >   		tpm2_flush_space(chip);
> >   		goto out;
> >   	}
> > 
> > -	rc = tpm2_map_response_body(chip, cc, buf, *bufsiz);
> > +	rc = tpm2_map_response_body(chip, chip->last_cc, buf, *bufsiz);
> >   	if (rc) {
> >   		tpm2_flush_space(chip);
> >   		goto out;
> 
> Rest looks good.
> 
> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>

Great, awesome, thank you for all your reviews!

/Jarkko
diff mbox series

Patch

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 422e3bb0bd3d..3bf0c51b7b4f 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -62,47 +62,6 @@  unsigned long tpm_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal)
 }
 EXPORT_SYMBOL_GPL(tpm_calc_ordinal_duration);
 
-static int tpm_validate_command(struct tpm_chip *chip,
-				 struct tpm_space *space,
-				 const u8 *cmd,
-				 size_t len)
-{
-	const struct tpm_input_header *header = (const void *)cmd;
-	int i;
-	u32 cc;
-	u32 attrs;
-	unsigned int nr_handles;
-
-	if (len < TPM_HEADER_SIZE)
-		return -EINVAL;
-
-	if (!space)
-		return 0;
-
-	if (chip->flags & TPM_CHIP_FLAG_TPM2 && chip->nr_commands) {
-		cc = be32_to_cpu(header->ordinal);
-
-		i = tpm2_find_cc(chip, cc);
-		if (i < 0) {
-			dev_dbg(&chip->dev, "0x%04X is an invalid command\n",
-				cc);
-			return -EOPNOTSUPP;
-		}
-
-		attrs = chip->cc_attrs_tbl[i];
-		nr_handles =
-			4 * ((attrs >> TPM2_CC_ATTR_CHANDLES) & GENMASK(2, 0));
-		if (len < TPM_HEADER_SIZE + 4 * nr_handles)
-			goto err_len;
-	}
-
-	return 0;
-err_len:
-	dev_dbg(&chip->dev,
-		"%s: insufficient command length %zu", __func__, len);
-	return -EINVAL;
-}
-
 static int tpm_request_locality(struct tpm_chip *chip, unsigned int flags)
 {
 	int rc;
@@ -172,20 +131,8 @@  static ssize_t tpm_try_transmit(struct tpm_chip *chip,
 	u32 count, ordinal;
 	unsigned long stop;
 
-	rc = tpm_validate_command(chip, space, buf, bufsiz);
-	if (rc == -EINVAL)
-		return rc;
-	/*
-	 * If the command is not implemented by the TPM, synthesize a
-	 * response with a TPM2_RC_COMMAND_CODE return for user-space.
-	 */
-	if (rc == -EOPNOTSUPP) {
-		header->length = cpu_to_be32(sizeof(*header));
-		header->tag = cpu_to_be16(TPM2_ST_NO_SESSIONS);
-		header->return_code = cpu_to_be32(TPM2_RC_COMMAND_CODE |
-						  TSS2_RESMGR_TPM_RC_LAYER);
-		return sizeof(*header);
-	}
+	if (bufsiz < TPM_HEADER_SIZE)
+		return -EINVAL;
 
 	if (bufsiz > TPM_BUFSIZE)
 		bufsiz = TPM_BUFSIZE;
@@ -200,7 +147,18 @@  static ssize_t tpm_try_transmit(struct tpm_chip *chip,
 		return -E2BIG;
 	}
 
-	rc = tpm2_prepare_space(chip, space, ordinal, buf);
+	rc = tpm2_prepare_space(chip, space, buf, bufsiz);
+	/*
+	 * If the command is not implemented by the TPM, synthesize a
+	 * response with a TPM2_RC_COMMAND_CODE return for user-space.
+	 */
+	if (rc == -EOPNOTSUPP) {
+		header->length = cpu_to_be32(sizeof(*header));
+		header->tag = cpu_to_be16(TPM2_ST_NO_SESSIONS);
+		header->return_code = cpu_to_be32(TPM2_RC_COMMAND_CODE |
+						  TSS2_RESMGR_TPM_RC_LAYER);
+		return sizeof(*header);
+	}
 	if (rc)
 		return rc;
 
@@ -251,7 +209,7 @@  static ssize_t tpm_try_transmit(struct tpm_chip *chip,
 	if (rc)
 		tpm2_flush_space(chip);
 	else
-		rc = tpm2_commit_space(chip, space, ordinal, buf, &len);
+		rc = tpm2_commit_space(chip, space, buf, &len);
 
 	return rc ? rc : len;
 }
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 229ac42b644e..8503dd261897 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -264,6 +264,7 @@  struct tpm_chip {
 #endif /* CONFIG_ACPI */
 
 	struct tpm_space work_space;
+	u32 last_cc;
 	u32 nr_commands;
 	u32 *cc_attrs_tbl;
 
@@ -580,10 +581,10 @@  int tpm2_find_cc(struct tpm_chip *chip, u32 cc);
 int tpm2_init_space(struct tpm_space *space);
 void tpm2_del_space(struct tpm_chip *chip, struct tpm_space *space);
 void tpm2_flush_space(struct tpm_chip *chip);
-int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u32 cc,
-		       u8 *cmd);
-int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space,
-		      u32 cc, u8 *buf, size_t *bufsiz);
+int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u8 *cmd,
+		       size_t cmdsiz);
+int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space, u8 *buf,
+		       size_t *bufsiz);
 
 int tpm_bios_log_setup(struct tpm_chip *chip);
 void tpm_bios_log_teardown(struct tpm_chip *chip);
diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
index 3d5f9577e5de..20c295fadd50 100644
--- a/drivers/char/tpm/tpm2-space.c
+++ b/drivers/char/tpm/tpm2-space.c
@@ -264,14 +264,55 @@  static int tpm2_map_command(struct tpm_chip *chip, u32 cc, u8 *cmd)
 	return 0;
 }
 
-int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u32 cc,
-		       u8 *cmd)
+static int tpm_validate_command(struct tpm_chip *chip, struct tpm_space *space,
+				const u8 *cmd, size_t len)
+{
+	const struct tpm_input_header *header = (const void *)cmd;
+	int i;
+	u32 cc;
+	u32 attrs;
+	unsigned int nr_handles;
+
+	if (len < TPM_HEADER_SIZE)
+		return -EINVAL;
+
+	if (chip->nr_commands) {
+		cc = be32_to_cpu(header->ordinal);
+
+		i = tpm2_find_cc(chip, cc);
+		if (i < 0) {
+			dev_dbg(&chip->dev, "0x%04X is an invalid command\n",
+				cc);
+			return -EOPNOTSUPP;
+		}
+
+		attrs = chip->cc_attrs_tbl[i];
+		nr_handles =
+			4 * ((attrs >> TPM2_CC_ATTR_CHANDLES) & GENMASK(2, 0));
+		if (len < TPM_HEADER_SIZE + 4 * nr_handles)
+			goto err_len;
+	}
+
+	return cc;
+err_len:
+	dev_dbg(&chip->dev, "%s: insufficient command length %zu", __func__,
+		len);
+	return -EINVAL;
+}
+
+int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u8 *cmd,
+		       size_t cmdsiz)
 {
 	int rc;
+	int cc;
 
 	if (!space)
 		return 0;
 
+	cc = tpm_validate_command(chip, space, cmd, cmdsiz);
+	if (cc < 0)
+		return cc;
+
 	memcpy(&chip->work_space.context_tbl, &space->context_tbl,
 	       sizeof(space->context_tbl));
 	memcpy(&chip->work_space.session_tbl, &space->session_tbl,
@@ -291,6 +332,7 @@  int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u32 cc,
 		return rc;
 	}
 
+	chip->last_cc = cc;
 	return 0;
 }
 
@@ -489,8 +531,8 @@  static int tpm2_save_space(struct tpm_chip *chip)
 	return 0;
 }
 
-int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space,
-		      u32 cc, u8 *buf, size_t *bufsiz)
+int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space, u8 *buf,
+		      size_t *bufsiz)
 {
 	struct tpm_output_header *header = (void *)buf;
 	int rc;
@@ -498,13 +540,13 @@  int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space,
 	if (!space)
 		return 0;
 
-	rc = tpm2_map_response_header(chip, cc, buf, *bufsiz);
+	rc = tpm2_map_response_header(chip, chip->last_cc, buf, *bufsiz);
 	if (rc) {
 		tpm2_flush_space(chip);
 		goto out;
 	}
 
-	rc = tpm2_map_response_body(chip, cc, buf, *bufsiz);
+	rc = tpm2_map_response_body(chip, chip->last_cc, buf, *bufsiz);
 	if (rc) {
 		tpm2_flush_space(chip);
 		goto out;