[tpmdd-devel,v2,4/7] tpm: infrastructure for TPM spaces

Submitted by Jarkko Sakkinen on Feb. 16, 2017, 7:25 p.m.

Details

Message ID 20170216192529.25467-5-jarkko.sakkinen@linux.intel.com
State New
Headers show

Commit Message

Jarkko Sakkinen Feb. 16, 2017, 7:25 p.m.
Added an ability to virtualize TPM commands into an isolated context
that we call a TPM space because the word context is already heavily
used in the TPM specification. Both the handle areas and bodies (where
necessary) are virtualized.

The mechanism works by adding a new parameter struct tpm_space to the
tpm_transmit() function. This new structure contains the list of virtual
handles and a buffer of page size (currently) for backing storage.

When tpm_transmit() is called with a struct tpm_space instance it will
execute the following sequence:

1. Take locks.
2. Load transient objects from the backing storage by using ContextLoad
   and map virtual handles to physical handles.
3. Perform the transaction.
4. Save transient objects to backing storage by using ContextSave and
   map resulting physical handle to virtual handle if there is such.

This commit does not implement virtualization support for hmac and
policy sessions.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 drivers/char/tpm/Makefile        |   2 +-
 drivers/char/tpm/tpm-chip.c      |   7 +
 drivers/char/tpm/tpm-dev.c       |   2 +-
 drivers/char/tpm/tpm-interface.c |  68 +++---
 drivers/char/tpm/tpm-sysfs.c     |   2 +-
 drivers/char/tpm/tpm.h           |  26 ++-
 drivers/char/tpm/tpm2-cmd.c      |  33 +--
 drivers/char/tpm/tpm2-space.c    | 431 +++++++++++++++++++++++++++++++++++++++
 8 files changed, 520 insertions(+), 51 deletions(-)
 create mode 100644 drivers/char/tpm/tpm2-space.c

Comments

Nayna Jain Feb. 21, 2017, 6:24 p.m.
On 02/17/2017 12:55 AM, Jarkko Sakkinen wrote:
> Added an ability to virtualize TPM commands into an isolated context
> that we call a TPM space because the word context is already heavily
> used in the TPM specification. Both the handle areas and bodies (where
> necessary) are virtualized.
>
> The mechanism works by adding a new parameter struct tpm_space to the
> tpm_transmit() function. This new structure contains the list of virtual
> handles and a buffer of page size (currently) for backing storage.
>
> When tpm_transmit() is called with a struct tpm_space instance it will
> execute the following sequence:
>
> 1. Take locks.
> 2. Load transient objects from the backing storage by using ContextLoad
>     and map virtual handles to physical handles.
> 3. Perform the transaction.
> 4. Save transient objects to backing storage by using ContextSave and
>     map resulting physical handle to virtual handle if there is such.
>
> This commit does not implement virtualization support for hmac and
> policy sessions.
>

If I have understood discussions correctly, I assume, that kernel TPM 
operations will also be routed via RM. And I think that is not happening 
now with these patches.

Am I missing something ?

Thanks & Regards,
    - Nayna


> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> ---
>   drivers/char/tpm/Makefile        |   2 +-
>   drivers/char/tpm/tpm-chip.c      |   7 +
>   drivers/char/tpm/tpm-dev.c       |   2 +-
>   drivers/char/tpm/tpm-interface.c |  68 +++---
>   drivers/char/tpm/tpm-sysfs.c     |   2 +-
>   drivers/char/tpm/tpm.h           |  26 ++-
>   drivers/char/tpm/tpm2-cmd.c      |  33 +--
>   drivers/char/tpm/tpm2-space.c    | 431 +++++++++++++++++++++++++++++++++++++++
>   8 files changed, 520 insertions(+), 51 deletions(-)
>   create mode 100644 drivers/char/tpm/tpm2-space.c
>
> diff --git a/drivers/char/tpm/Makefile b/drivers/char/tpm/Makefile
> index 3d386a8..8f07fcf 100644
> --- a/drivers/char/tpm/Makefile
> +++ b/drivers/char/tpm/Makefile
> @@ -3,7 +3,7 @@
>   #
>   obj-$(CONFIG_TCG_TPM) += tpm.o
>   tpm-y := tpm-interface.o tpm-dev.o tpm-sysfs.o tpm-chip.o tpm2-cmd.o \
> -		tpm1_eventlog.o tpm2_eventlog.o
> +	 tpm1_eventlog.o tpm2_eventlog.o tpm2-space.o
>   tpm-$(CONFIG_ACPI) += tpm_ppi.o tpm_acpi.o
>   tpm-$(CONFIG_OF) += tpm_of.o
>   obj-$(CONFIG_TCG_TIS_CORE) += tpm_tis_core.o
> diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
> index c406343..993b9ae 100644
> --- a/drivers/char/tpm/tpm-chip.c
> +++ b/drivers/char/tpm/tpm-chip.c
> @@ -128,6 +128,7 @@ static void tpm_dev_release(struct device *dev)
>   	mutex_unlock(&idr_lock);
>
>   	kfree(chip->log.bios_event_log);
> +	kfree(chip->work_space.context_buf);
>   	kfree(chip);
>   }
>
> @@ -189,6 +190,12 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
>   	chip->cdev.owner = THIS_MODULE;
>   	chip->cdev.kobj.parent = &chip->dev.kobj;
>
> +	chip->work_space.context_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
> +	if (!chip->work_space.context_buf) {
> +		rc = -ENOMEM;
> +		goto out;
> +	}
> +
>   	return chip;
>
>   out:
> diff --git a/drivers/char/tpm/tpm-dev.c b/drivers/char/tpm/tpm-dev.c
> index 02a8850..414553b 100644
> --- a/drivers/char/tpm/tpm-dev.c
> +++ b/drivers/char/tpm/tpm-dev.c
> @@ -147,7 +147,7 @@ static ssize_t tpm_write(struct file *file, const char __user *buf,
>   		mutex_unlock(&priv->buffer_mutex);
>   		return -EPIPE;
>   	}
> -	out_size = tpm_transmit(priv->chip, priv->data_buffer,
> +	out_size = tpm_transmit(priv->chip, NULL, priv->data_buffer,
>   				sizeof(priv->data_buffer), 0);
>
>   	tpm_put_ops(priv->chip);
> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> index 20b1fe3..db5ffe9 100644
> --- a/drivers/char/tpm/tpm-interface.c
> +++ b/drivers/char/tpm/tpm-interface.c
> @@ -376,11 +376,12 @@ static bool tpm_validate_command(struct tpm_chip *chip, const u8 *cmd,
>    *     0 when the operation is successful.
>    *     A negative number for system errors (errno).
>    */
> -ssize_t tpm_transmit(struct tpm_chip *chip, const u8 *buf, size_t bufsiz,
> -		     unsigned int flags)
> +ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space,
> +		     u8 *buf, size_t bufsiz, unsigned int flags)
>   {
> -	const struct tpm_output_header *header = (void *)buf;
> -	ssize_t rc;
> +	struct tpm_output_header *header = (void *)buf;
> +	int rc;
> +	ssize_t len = 0;
>   	u32 count, ordinal;
>   	unsigned long stop;
>
> @@ -406,10 +407,14 @@ ssize_t tpm_transmit(struct tpm_chip *chip, const u8 *buf, size_t bufsiz,
>   	if (chip->dev.parent)
>   		pm_runtime_get_sync(chip->dev.parent);
>
> +	rc = tpm2_prepare_space(chip, space, ordinal, buf);
> +	if (rc)
> +		goto out;
> +
>   	rc = chip->ops->send(chip, (u8 *) buf, count);
>   	if (rc < 0) {
>   		dev_err(&chip->dev,
> -			"tpm_transmit: tpm_send: error %zd\n", rc);
> +			"tpm_transmit: tpm_send: error %d\n", rc);
>   		goto out;
>   	}
>
> @@ -442,18 +447,23 @@ ssize_t tpm_transmit(struct tpm_chip *chip, const u8 *buf, size_t bufsiz,
>   	goto out;
>
>   out_recv:
> -	rc = chip->ops->recv(chip, (u8 *) buf, bufsiz);
> -	if (rc < 0) {
> +	len = chip->ops->recv(chip, (u8 *) buf, bufsiz);
> +	if (len < 0) {
>   		dev_err(&chip->dev,
> -			"tpm_transmit: tpm_recv: error %zd\n", rc);
> +			"tpm_transmit: tpm_recv: error %d\n", rc);
> +		rc = len;
>   		goto out;
> -	} else if (rc < TPM_HEADER_SIZE) {
> +	} else if (len < TPM_HEADER_SIZE) {
>   		rc = -EFAULT;
>   		goto out;
>   	}
>
> -	if (rc != be32_to_cpu(header->length))
> +	if (len != be32_to_cpu(header->length)) {
> +		rc = -EFAULT;
>   		goto out;
> +	}
> +
> +	rc = tpm2_commit_space(chip, space, ordinal, buf, &len);
>
>   out:
>   	if (chip->dev.parent)
> @@ -461,7 +471,7 @@ ssize_t tpm_transmit(struct tpm_chip *chip, const u8 *buf, size_t bufsiz,
>
>   	if (!(flags & TPM_TRANSMIT_UNLOCKED))
>   		mutex_unlock(&chip->tpm_mutex);
> -	return rc;
> +	return rc ? rc : len;
>   }
>
>   /**
> @@ -480,15 +490,16 @@ ssize_t tpm_transmit(struct tpm_chip *chip, const u8 *buf, size_t bufsiz,
>    *     A negative number for system errors (errno).
>    *     A positive number for a TPM error.
>    */
> -ssize_t tpm_transmit_cmd(struct tpm_chip *chip, const void *buf,
> -			 size_t bufsiz, size_t min_rsp_body_length,
> -			 unsigned int flags, const char *desc)
> +ssize_t tpm_transmit_cmd(struct tpm_chip *chip, struct tpm_space *space,
> +			 const void *buf, size_t bufsiz,
> +			 size_t min_rsp_body_length, unsigned int flags,
> +			 const char *desc)
>   {
>   	const struct tpm_output_header *header = buf;
>   	int err;
>   	ssize_t len;
>
> -	len = tpm_transmit(chip, (const u8 *)buf, bufsiz, flags);
> +	len = tpm_transmit(chip, space, (u8 *)buf, bufsiz, flags);
>   	if (len <  0)
>   		return len;
>
> @@ -541,7 +552,7 @@ ssize_t tpm_getcap(struct tpm_chip *chip, u32 subcap_id, cap_t *cap,
>   		tpm_cmd.params.getcap_in.subcap_size = cpu_to_be32(4);
>   		tpm_cmd.params.getcap_in.subcap = cpu_to_be32(subcap_id);
>   	}
> -	rc = tpm_transmit_cmd(chip, &tpm_cmd, TPM_INTERNAL_RESULT_SIZE,
> +	rc = tpm_transmit_cmd(chip, NULL, &tpm_cmd, TPM_INTERNAL_RESULT_SIZE,
>   			      min_cap_length, 0, desc);
>   	if (!rc)
>   		*cap = tpm_cmd.params.getcap_out.cap;
> @@ -565,7 +576,8 @@ static int tpm_startup(struct tpm_chip *chip, __be16 startup_type)
>   	start_cmd.header.in = tpm_startup_header;
>
>   	start_cmd.params.startup_in.startup_type = startup_type;
> -	return tpm_transmit_cmd(chip, &start_cmd, TPM_INTERNAL_RESULT_SIZE, 0,
> +	return tpm_transmit_cmd(chip, NULL, &start_cmd,
> +				TPM_INTERNAL_RESULT_SIZE, 0,
>   				0, "attempting to start the TPM");
>   }
>
> @@ -722,8 +734,8 @@ static int tpm_continue_selftest(struct tpm_chip *chip)
>   	struct tpm_cmd_t cmd;
>
>   	cmd.header.in = continue_selftest_header;
> -	rc = tpm_transmit_cmd(chip, &cmd, CONTINUE_SELFTEST_RESULT_SIZE, 0, 0,
> -			      "continue selftest");
> +	rc = tpm_transmit_cmd(chip, NULL, &cmd, CONTINUE_SELFTEST_RESULT_SIZE,
> +			      0, 0, "continue selftest");
>   	return rc;
>   }
>
> @@ -743,7 +755,7 @@ int tpm_pcr_read_dev(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
>
>   	cmd.header.in = pcrread_header;
>   	cmd.params.pcrread_in.pcr_idx = cpu_to_be32(pcr_idx);
> -	rc = tpm_transmit_cmd(chip, &cmd, READ_PCR_RESULT_SIZE,
> +	rc = tpm_transmit_cmd(chip, NULL, &cmd, READ_PCR_RESULT_SIZE,
>   			      READ_PCR_RESULT_BODY_SIZE, 0,
>   			      "attempting to read a pcr value");
>
> @@ -855,7 +867,7 @@ int tpm_pcr_extend(u32 chip_num, int pcr_idx, const u8 *hash)
>   	cmd.header.in = pcrextend_header;
>   	cmd.params.pcrextend_in.pcr_idx = cpu_to_be32(pcr_idx);
>   	memcpy(cmd.params.pcrextend_in.hash, hash, TPM_DIGEST_SIZE);
> -	rc = tpm_transmit_cmd(chip, &cmd, EXTEND_PCR_RESULT_SIZE,
> +	rc = tpm_transmit_cmd(chip, NULL, &cmd, EXTEND_PCR_RESULT_SIZE,
>   			      EXTEND_PCR_RESULT_BODY_SIZE, 0,
>   			      "attempting extend a PCR value");
>
> @@ -960,8 +972,8 @@ int tpm_send(u32 chip_num, void *cmd, size_t buflen)
>   	if (chip == NULL)
>   		return -ENODEV;
>
> -	rc = tpm_transmit_cmd(chip, cmd, buflen, 0, 0, "attempting tpm_cmd");
> -
> +	rc = tpm_transmit_cmd(chip, NULL, cmd, buflen, 0, 0,
> +			      "attempting tpm_cmd");
>   	tpm_put_ops(chip);
>   	return rc;
>   }
> @@ -1062,16 +1074,16 @@ int tpm_pm_suspend(struct device *dev)
>   		cmd.params.pcrextend_in.pcr_idx = cpu_to_be32(tpm_suspend_pcr);
>   		memcpy(cmd.params.pcrextend_in.hash, dummy_hash,
>   		       TPM_DIGEST_SIZE);
> -		rc = tpm_transmit_cmd(chip, &cmd, EXTEND_PCR_RESULT_SIZE,
> -				     EXTEND_PCR_RESULT_BODY_SIZE, 0,
> +		rc = tpm_transmit_cmd(chip, NULL, &cmd, EXTEND_PCR_RESULT_SIZE,
> +				      EXTEND_PCR_RESULT_BODY_SIZE, 0,
>   				      "extending dummy pcr before suspend");
>   	}
>
>   	/* now do the actual savestate */
>   	for (try = 0; try < TPM_RETRY; try++) {
>   		cmd.header.in = savestate_header;
> -		rc = tpm_transmit_cmd(chip, &cmd, SAVESTATE_RESULT_SIZE, 0,
> -				      0, NULL);
> +		rc = tpm_transmit_cmd(chip, NULL, &cmd, SAVESTATE_RESULT_SIZE,
> +				      0, 0, NULL);
>
>   		/*
>   		 * If the TPM indicates that it is too busy to respond to
> @@ -1154,7 +1166,7 @@ int tpm_get_random(u32 chip_num, u8 *out, size_t max)
>   		tpm_cmd.header.in = tpm_getrandom_header;
>   		tpm_cmd.params.getrandom_in.num_bytes = cpu_to_be32(num_bytes);
>
> -		err = tpm_transmit_cmd(chip, &tpm_cmd,
> +		err = tpm_transmit_cmd(chip, NULL, &tpm_cmd,
>   				       TPM_GETRANDOM_RESULT_SIZE + num_bytes,
>   				       offsetof(struct tpm_getrandom_out,
>   						rng_data),
> diff --git a/drivers/char/tpm/tpm-sysfs.c b/drivers/char/tpm/tpm-sysfs.c
> index 2f596d7..55405db 100644
> --- a/drivers/char/tpm/tpm-sysfs.c
> +++ b/drivers/char/tpm/tpm-sysfs.c
> @@ -40,7 +40,7 @@ static ssize_t pubek_show(struct device *dev, struct device_attribute *attr,
>   	struct tpm_chip *chip = to_tpm_chip(dev);
>
>   	tpm_cmd.header.in = tpm_readpubek_header;
> -	err = tpm_transmit_cmd(chip, &tpm_cmd, READ_PUBEK_RESULT_SIZE,
> +	err = tpm_transmit_cmd(chip, NULL, &tpm_cmd, READ_PUBEK_RESULT_SIZE,
>   			       READ_PUBEK_RESULT_MIN_BODY_SIZE, 0,
>   			       "attempting to read the PUBEK");
>   	if (err)
> diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
> index 0ec1cf0..97e48a4 100644
> --- a/drivers/char/tpm/tpm.h
> +++ b/drivers/char/tpm/tpm.h
> @@ -89,10 +89,13 @@ enum tpm2_structures {
>   };
>
>   enum tpm2_return_codes {
> +	TPM2_RC_SUCCESS		= 0x0000,
>   	TPM2_RC_HASH		= 0x0083, /* RC_FMT1 */
> +	TPM2_RC_HANDLE		= 0x008B,
>   	TPM2_RC_INITIALIZE	= 0x0100, /* RC_VER1 */
>   	TPM2_RC_DISABLED	= 0x0120,
>   	TPM2_RC_TESTING		= 0x090A, /* RC_WARN */
> +	TPM2_RC_REFERENCE_H0	= 0x0910,
>   };
>
>   enum tpm2_algorithms {
> @@ -114,6 +117,7 @@ enum tpm2_command_codes {
>   	TPM2_CC_CREATE		= 0x0153,
>   	TPM2_CC_LOAD		= 0x0157,
>   	TPM2_CC_UNSEAL		= 0x015E,
> +	TPM2_CC_CONTEXT_LOAD	= 0x0161,
>   	TPM2_CC_CONTEXT_SAVE	= 0x0162,
>   	TPM2_CC_FLUSH_CONTEXT	= 0x0165,
>   	TPM2_CC_GET_CAPABILITY	= 0x017A,
> @@ -128,6 +132,7 @@ enum tpm2_permanent_handles {
>   };
>
>   enum tpm2_capabilities {
> +	TPM2_CAP_HANDLES	= 1,
>   	TPM2_CAP_COMMANDS	= 2,
>   	TPM2_CAP_PCRS		= 5,
>   	TPM2_CAP_TPM_PROPERTIES = 6,
> @@ -153,6 +158,11 @@ enum tpm2_cc_attrs {
>
>   #define TPM_PPI_VERSION_LEN		3
>
> +struct tpm_space {
> +	u32 context_tbl[3];
> +	u8 *context_buf;
> +};
> +
>   enum tpm_chip_flags {
>   	TPM_CHIP_FLAG_TPM2		= BIT(1),
>   	TPM_CHIP_FLAG_IRQ		= BIT(2),
> @@ -211,6 +221,7 @@ struct tpm_chip {
>   	char ppi_version[TPM_PPI_VERSION_LEN + 1];
>   #endif /* CONFIG_ACPI */
>
> +	struct tpm_space work_space;
>   	u32 nr_commands;
>   	u32 *cc_attrs_tbl;
>   };
> @@ -507,10 +518,11 @@ enum tpm_transmit_flags {
>   	TPM_TRANSMIT_UNLOCKED	= BIT(0),
>   };
>
> -ssize_t tpm_transmit(struct tpm_chip *chip, const u8 *buf, size_t bufsiz,
> -		     unsigned int flags);
> -ssize_t tpm_transmit_cmd(struct tpm_chip *chip, const void *buf, size_t bufsiz,
> -			 size_t min_rsp_body_len, unsigned int flags,
> +ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space,
> +		     u8 *buf, size_t bufsiz, unsigned int flags);
> +ssize_t tpm_transmit_cmd(struct tpm_chip *chip, struct tpm_space *space,
> +			 const void *buf, size_t bufsiz,
> +			 size_t min_rsp_body_length, unsigned int flags,
>   			 const char *desc);
>   ssize_t tpm_getcap(struct tpm_chip *chip, u32 subcap_id, cap_t *cap,
>   		   const char *desc, size_t min_cap_length);
> @@ -572,4 +584,10 @@ unsigned long tpm2_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal);
>   int tpm2_probe(struct tpm_chip *chip);
>   ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip);
>   int tpm2_find_cc(struct tpm_chip *chip, u32 cc);
> +int tpm2_init_space(struct tpm_space *space);
> +void tpm2_del_space(struct tpm_space *space);
> +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);
>   #endif
> diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
> index 897902a..96121b3 100644
> --- a/drivers/char/tpm/tpm2-cmd.c
> +++ b/drivers/char/tpm/tpm2-cmd.c
> @@ -266,7 +266,7 @@ int tpm2_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
>   	       sizeof(cmd.params.pcrread_in.pcr_select));
>   	cmd.params.pcrread_in.pcr_select[pcr_idx >> 3] = 1 << (pcr_idx & 0x7);
>
> -	rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd),
> +	rc = tpm_transmit_cmd(chip, NULL, &cmd, sizeof(cmd),
>   			      TPM2_PCR_READ_RESP_BODY_SIZE,
>   			      0, "attempting to read a pcr value");
>   	if (rc == 0) {
> @@ -333,7 +333,7 @@ int tpm2_pcr_extend(struct tpm_chip *chip, int pcr_idx, u32 count,
>   		}
>   	}
>
> -	rc = tpm_transmit_cmd(chip, buf.data, PAGE_SIZE, 0, 0,
> +	rc = tpm_transmit_cmd(chip, NULL, buf.data, PAGE_SIZE, 0, 0,
>   			      "attempting extend a PCR value");
>
>   	tpm_buf_destroy(&buf);
> @@ -382,7 +382,7 @@ int tpm2_get_random(struct tpm_chip *chip, u8 *out, size_t max)
>   		cmd.header.in = tpm2_getrandom_header;
>   		cmd.params.getrandom_in.size = cpu_to_be16(num_bytes);
>
> -		err = tpm_transmit_cmd(chip, &cmd, sizeof(cmd),
> +		err = tpm_transmit_cmd(chip, NULL, &cmd, sizeof(cmd),
>   				       offsetof(struct tpm2_get_random_out,
>   						buffer),
>   				       0, "attempting get random");
> @@ -441,7 +441,7 @@ void tpm2_flush_context_cmd(struct tpm_chip *chip, u32 handle,
>
>   	tpm_buf_append_u32(&buf, handle);
>
> -	(void) tpm_transmit_cmd(chip, buf.data, PAGE_SIZE, 0, flags,
> +	(void) tpm_transmit_cmd(chip, NULL, buf.data, PAGE_SIZE, 0, flags,
>   				"flushing context");
>
>   	tpm_buf_destroy(&buf);
> @@ -557,7 +557,7 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
>   		goto out;
>   	}
>
> -	rc = tpm_transmit_cmd(chip, buf.data, PAGE_SIZE, 4, 0,
> +	rc = tpm_transmit_cmd(chip, NULL, buf.data, PAGE_SIZE, 4, 0,
>   			      "sealing data");
>   	if (rc)
>   		goto out;
> @@ -641,7 +641,7 @@ static int tpm2_load_cmd(struct tpm_chip *chip,
>   		goto out;
>   	}
>
> -	rc = tpm_transmit_cmd(chip, buf.data, PAGE_SIZE, 4, flags,
> +	rc = tpm_transmit_cmd(chip, NULL, buf.data, PAGE_SIZE, 4, flags,
>   			      "loading blob");
>   	if (!rc)
>   		*blob_handle = be32_to_cpup(
> @@ -693,7 +693,7 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
>   			     options->blobauth /* hmac */,
>   			     TPM_DIGEST_SIZE);
>
> -	rc = tpm_transmit_cmd(chip, buf.data, PAGE_SIZE, 6, flags,
> +	rc = tpm_transmit_cmd(chip, NULL, buf.data, PAGE_SIZE, 6, flags,
>   			      "unsealing");
>   	if (rc > 0)
>   		rc = -EPERM;
> @@ -770,7 +770,7 @@ ssize_t tpm2_get_tpm_pt(struct tpm_chip *chip, u32 property_id,  u32 *value,
>   	cmd.params.get_tpm_pt_in.property_id = cpu_to_be32(property_id);
>   	cmd.params.get_tpm_pt_in.property_cnt = cpu_to_be32(1);
>
> -	rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd),
> +	rc = tpm_transmit_cmd(chip, NULL, &cmd, sizeof(cmd),
>   			      TPM2_GET_TPM_PT_OUT_BODY_SIZE, 0, desc);
>   	if (!rc)
>   		*value = be32_to_cpu(cmd.params.get_tpm_pt_out.value);
> @@ -805,7 +805,7 @@ static int tpm2_startup(struct tpm_chip *chip, u16 startup_type)
>   	cmd.header.in = tpm2_startup_header;
>
>   	cmd.params.startup_in.startup_type = cpu_to_be16(startup_type);
> -	return tpm_transmit_cmd(chip, &cmd, sizeof(cmd), 0, 0,
> +	return tpm_transmit_cmd(chip, NULL, &cmd, sizeof(cmd), 0, 0,
>   				"attempting to start the TPM");
>   }
>
> @@ -834,7 +834,7 @@ void tpm2_shutdown(struct tpm_chip *chip, u16 shutdown_type)
>   	cmd.header.in = tpm2_shutdown_header;
>   	cmd.params.startup_in.startup_type = cpu_to_be16(shutdown_type);
>
> -	rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd), 0, 0,
> +	rc = tpm_transmit_cmd(chip, NULL, &cmd, sizeof(cmd), 0, 0,
>   			      "stopping the TPM");
>
>   	/* In places where shutdown command is sent there's no much we can do
> @@ -898,7 +898,7 @@ static int tpm2_start_selftest(struct tpm_chip *chip, bool full)
>   	cmd.header.in = tpm2_selftest_header;
>   	cmd.params.selftest_in.full_test = full;
>
> -	rc = tpm_transmit_cmd(chip, &cmd, TPM2_SELF_TEST_IN_SIZE, 0, 0,
> +	rc = tpm_transmit_cmd(chip, NULL, &cmd, TPM2_SELF_TEST_IN_SIZE, 0, 0,
>   			      "continue selftest");
>
>   	/* At least some prototype chips seem to give RC_TESTING error
> @@ -949,7 +949,8 @@ static int tpm2_do_selftest(struct tpm_chip *chip)
>   		cmd.params.pcrread_in.pcr_select[1] = 0x00;
>   		cmd.params.pcrread_in.pcr_select[2] = 0x00;
>
> -		rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd), 0, 0, NULL);
> +		rc = tpm_transmit_cmd(chip, NULL, &cmd, sizeof(cmd), 0, 0,
> +				      NULL);
>   		if (rc < 0)
>   			break;
>
> @@ -982,7 +983,7 @@ int tpm2_probe(struct tpm_chip *chip)
>   	cmd.params.get_tpm_pt_in.property_id = cpu_to_be32(0x100);
>   	cmd.params.get_tpm_pt_in.property_cnt = cpu_to_be32(1);
>
> -	rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd), 0, 0, NULL);
> +	rc = tpm_transmit_cmd(chip, NULL, &cmd, sizeof(cmd), 0, 0, NULL);
>   	if (rc <  0)
>   		return rc;
>
> @@ -1022,8 +1023,8 @@ static int tpm2_get_cc_attrs_tbl(struct tpm_chip *chip)
>   	tpm_buf_append_u32(&buf, TPM2_CC_FIRST);
>   	tpm_buf_append_u32(&buf, nr_commands);
>
> -	rc = tpm_transmit_cmd(chip, buf.data, PAGE_SIZE, 9 + 4 * nr_commands,
> -			      0, NULL);
> +	rc = tpm_transmit_cmd(chip, NULL, buf.data, PAGE_SIZE,
> +			      9 + 4 * nr_commands, 0, NULL);
>   	if (rc) {
>   		tpm_buf_destroy(&buf);
>   		goto out;
> @@ -1136,7 +1137,7 @@ ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip)
>   	tpm_buf_append_u32(&buf, 0);
>   	tpm_buf_append_u32(&buf, 1);
>
> -	rc = tpm_transmit_cmd(chip, buf.data, PAGE_SIZE, 9, 0,
> +	rc = tpm_transmit_cmd(chip, NULL, buf.data, PAGE_SIZE, 9, 0,
>   			      "get tpm pcr allocation");
>   	if (rc)
>   		goto out;
> diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
> new file mode 100644
> index 0000000..e955548
> --- /dev/null
> +++ b/drivers/char/tpm/tpm2-space.c
> @@ -0,0 +1,431 @@
> +/*
> + * Copyright (C) 2016 Intel Corporation
> + *
> + * Authors:
> + * Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> + *
> + * Maintained by: <tpmdd-devel@lists.sourceforge.net>
> + *
> + * This file contains TPM2 protocol implementations of the commands
> + * used by the kernel internally.
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License
> + * as published by the Free Software Foundation; version 2
> + * of the License.
> + */
> +
> +#include <linux/gfp.h>
> +#include <asm/unaligned.h>
> +#include "tpm.h"
> +
> +enum tpm2_handle_types {
> +	TPM2_HT_HMAC_SESSION	= 0x02000000,
> +	TPM2_HT_POLICY_SESSION	= 0x03000000,
> +	TPM2_HT_TRANSIENT	= 0x80000000,
> +};
> +
> +struct tpm2_context {
> +	__be64 sequence;
> +	__be32 saved_handle;
> +	__be32 hierarchy;
> +	__be16 blob_size;
> +} __packed;
> +
> +int tpm2_init_space(struct tpm_space *space)
> +{
> +	space->context_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
> +	if (!space->context_buf)
> +		return -ENOMEM;
> +
> +	return 0;
> +}
> +
> +void tpm2_del_space(struct tpm_space *space)
> +{
> +	kfree(space->context_buf);
> +}
> +
> +static int tpm2_load_context(struct tpm_chip *chip, u8 *buf,
> +			     unsigned int *offset, u32 *handle)
> +{
> +	struct tpm_buf tbuf;
> +	struct tpm2_context *ctx;
> +	unsigned int body_size;
> +	int rc;
> +
> +	rc = tpm_buf_init(&tbuf, TPM2_ST_NO_SESSIONS, TPM2_CC_CONTEXT_LOAD);
> +	if (rc)
> +		return rc;
> +
> +	ctx = (struct tpm2_context *)&buf[*offset];
> +	body_size = sizeof(*ctx) + be16_to_cpu(ctx->blob_size);
> +	tpm_buf_append(&tbuf, &buf[*offset], body_size);
> +
> +	rc = tpm_transmit_cmd(chip, NULL, tbuf.data, PAGE_SIZE, 4,
> +			      TPM_TRANSMIT_UNLOCKED, NULL);
> +	if (rc < 0) {
> +		dev_warn(&chip->dev, "%s: failed with a system error %d\n",
> +			 __func__, rc);
> +		tpm_buf_destroy(&tbuf);
> +		return -EFAULT;
> +	} else if (rc > 0) {
> +		dev_warn(&chip->dev, "%s: failed with a TPM error 0x%04X\n",
> +			 __func__, rc);
> +		tpm_buf_destroy(&tbuf);
> +		return -EFAULT;
> +	}
> +
> +	*handle = be32_to_cpup((__be32 *)&tbuf.data[TPM_HEADER_SIZE]);
> +	*offset += body_size;
> +
> +	tpm_buf_destroy(&tbuf);
> +	return 0;
> +}
> +
> +static int tpm2_save_context(struct tpm_chip *chip, u32 handle, u8 *buf,
> +			     unsigned int buf_size, unsigned int *offset)
> +{
> +	struct tpm_buf tbuf;
> +	unsigned int body_size;
> +	int rc;
> +
> +	rc = tpm_buf_init(&tbuf, TPM2_ST_NO_SESSIONS, TPM2_CC_CONTEXT_SAVE);
> +	if (rc)
> +		return rc;
> +
> +	tpm_buf_append_u32(&tbuf, handle);
> +
> +	rc = tpm_transmit_cmd(chip, NULL, tbuf.data, PAGE_SIZE, 0,
> +			      TPM_TRANSMIT_UNLOCKED, NULL);
> +	if (rc < 0) {
> +		dev_warn(&chip->dev, "%s: failed with a system error %d\n",
> +			 __func__, rc);
> +		tpm_buf_destroy(&tbuf);
> +		return -EFAULT;
> +	} else if (tpm2_rc_value(rc) == TPM2_RC_REFERENCE_H0) {
> +		tpm_buf_destroy(&tbuf);
> +		return -ENOENT;
> +	} else if (rc) {
> +		dev_warn(&chip->dev, "%s: failed with a TPM error 0x%04X\n",
> +			 __func__, rc);
> +		tpm_buf_destroy(&tbuf);
> +		return -EFAULT;
> +	}
> +
> +	body_size = tpm_buf_length(&tbuf) - TPM_HEADER_SIZE;
> +	if ((*offset + body_size) > buf_size) {
> +		dev_warn(&chip->dev, "%s: out of backing storage\n", __func__);
> +		tpm_buf_destroy(&tbuf);
> +		return -ENOMEM;
> +	}
> +
> +	memcpy(&buf[*offset], &tbuf.data[TPM_HEADER_SIZE], body_size);
> +	tpm2_flush_context_cmd(chip, handle, TPM_TRANSMIT_UNLOCKED);
> +	*offset += body_size;
> +	tpm_buf_destroy(&tbuf);
> +	return 0;
> +}
> +
> +static void tpm2_flush_space(struct tpm_chip *chip)
> +{
> +	struct tpm_space *space = &chip->work_space;
> +	int i;
> +
> +	for (i = 0; i < ARRAY_SIZE(space->context_tbl); i++)
> +		if (space->context_tbl[i] && ~space->context_tbl[i])
> +			tpm2_flush_context_cmd(chip, space->context_tbl[i],
> +					       TPM_TRANSMIT_UNLOCKED);
> +}
> +
> +static int tpm2_load_space(struct tpm_chip *chip)
> +{
> +	struct tpm_space *space = &chip->work_space;
> +	unsigned int offset;
> +	int i;
> +	int rc;
> +
> +	for (i = 0, offset = 0; i < ARRAY_SIZE(space->context_tbl); i++) {
> +		if (!space->context_tbl[i])
> +			continue;
> +
> +		/* sanity check, should never happen */
> +		if (~space->context_tbl[i]) {
> +			dev_err(&chip->dev, "context table is inconsistent");
> +			return -EFAULT;
> +		}
> +
> +		rc = tpm2_load_context(chip, space->context_buf, &offset,
> +				       &space->context_tbl[i]);
> +		if (rc)
> +			return rc;
> +	}
> +
> +	return 0;
> +}
> +
> +static bool tpm2_map_to_phandle(struct tpm_space *space, void *handle)
> +{
> +	u32 vhandle = be32_to_cpup((__be32 *)handle);
> +	u32 phandle;
> +	int i;
> +
> +	i = 0xFFFFFF - (vhandle & 0xFFFFFF);
> +	if (i > ARRAY_SIZE(space->context_tbl) || !space->context_tbl[i])
> +		return false;
> +
> +	phandle = space->context_tbl[i];
> +	*((__be32 *)handle) = cpu_to_be32(phandle);
> +	return true;
> +}
> +
> +static int tpm2_map_command(struct tpm_chip *chip, u32 cc, u8 *cmd)
> +{
> +	struct tpm_space *space = &chip->work_space;
> +	unsigned int nr_handles;
> +	u32 attrs;
> +	u32 *handle;
> +	int i;
> +
> +	i = tpm2_find_cc(chip, cc);
> +	if (i < 0)
> +		return -EINVAL;
> +
> +	attrs = chip->cc_attrs_tbl[i];
> +	nr_handles = (attrs >> TPM2_CC_ATTR_CHANDLES) & GENMASK(2, 0);
> +
> +	handle = (u32 *)&cmd[TPM_HEADER_SIZE];
> +	for (i = 0; i < nr_handles; i++, handle++) {
> +		if ((be32_to_cpu(*handle) & 0xFF000000) == TPM2_HT_TRANSIENT) {
> +			if (!tpm2_map_to_phandle(space, handle))
> +				return -EINVAL;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u32 cc,
> +		       u8 *cmd)
> +{
> +	int rc;
> +
> +	if (!space)
> +		return 0;
> +
> +	memcpy(&chip->work_space.context_tbl, &space->context_tbl,
> +	       sizeof(space->context_tbl));
> +	memcpy(chip->work_space.context_buf, space->context_buf, PAGE_SIZE);
> +
> +	rc = tpm2_load_space(chip);
> +	if (rc) {
> +		tpm2_flush_space(chip);
> +		return rc;
> +	}
> +
> +	rc = tpm2_map_command(chip, cc, cmd);
> +	if (rc) {
> +		tpm2_flush_space(chip);
> +		return rc;
> +	}
> +
> +	return 0;
> +}
> +
> +static u32 tpm2_map_to_vhandle(struct tpm_space *space, u32 phandle, bool alloc)
> +{
> +	int i;
> +
> +	for (i = 0; i < ARRAY_SIZE(space->context_tbl); i++) {
> +		if (alloc) {
> +			if (!space->context_tbl[i]) {
> +				space->context_tbl[i] = phandle;
> +				break;
> +			}
> +		} else if (space->context_tbl[i] == phandle)
> +			break;
> +	}
> +
> +	if (i == ARRAY_SIZE(space->context_tbl))
> +		return 0;
> +
> +	return TPM2_HT_TRANSIENT | (0xFFFFFF - i);
> +}
> +
> +static int tpm2_map_response_header(struct tpm_chip *chip, u32 cc, u8 *rsp,
> +				    size_t len)
> +{
> +	struct tpm_space *space = &chip->work_space;
> +	struct tpm_output_header *header = (void *)rsp;
> +	u32 phandle;
> +	u32 phandle_type;
> +	u32 vhandle;
> +	u32 attrs;
> +	int i;
> +
> +	if (be32_to_cpu(header->return_code) != TPM2_RC_SUCCESS)
> +		return 0;
> +
> +	i = tpm2_find_cc(chip, cc);
> +	/* sanity check, should never happen */
> +	if (i < 0)
> +		return -EFAULT;
> +
> +	attrs = chip->cc_attrs_tbl[i];
> +	if (!((attrs >> TPM2_CC_ATTR_RHANDLE) & 1))
> +		return 0;
> +
> +	phandle = be32_to_cpup((__be32 *)&rsp[TPM_HEADER_SIZE]);
> +	phandle_type = phandle & 0xFF000000;
> +
> +	switch (phandle_type) {
> +	case TPM2_HT_TRANSIENT:
> +		vhandle = tpm2_map_to_vhandle(space, phandle, true);
> +		if (!vhandle)
> +			goto out_no_slots;
> +
> +		*(__be32 *)&rsp[TPM_HEADER_SIZE] = cpu_to_be32(vhandle);
> +		break;
> +	case TPM2_HT_HMAC_SESSION:
> +	case TPM2_HT_POLICY_SESSION:
> +		break;
> +	default:
> +		dev_err(&chip->dev, "%s: unknown handle 0x%08X\n",
> +			__func__, phandle);
> +		break;
> +	};
> +
> +	return 0;
> +out_no_slots:
> +	tpm2_flush_context_cmd(chip, phandle, TPM_TRANSMIT_UNLOCKED);
> +	dev_warn(&chip->dev, "%s: out of slots for 0x%08X\n", __func__,
> +		 phandle);
> +	return -ENOMEM;
> +}
> +
> +struct tpm2_cap_handles {
> +	u8 more_data;
> +	__be32 capability;
> +	__be32 count;
> +	__be32 handles[];
> +} __packed;
> +
> +static int tpm2_map_response_body(struct tpm_chip *chip, u32 cc, u8 *rsp,
> +				  size_t len)
> +{
> +	struct tpm_space *space = &chip->work_space;
> +	struct tpm_output_header *header = (void *)rsp;
> +	struct tpm2_cap_handles *data;
> +	u32 phandle;
> +	u32 phandle_type;
> +	u32 vhandle;
> +	int i;
> +	int j;
> +
> +	if (cc != TPM2_CC_GET_CAPABILITY ||
> +	    be32_to_cpu(header->return_code) != TPM2_RC_SUCCESS) {
> +		return 0;
> +	}
> +
> +	if (len < TPM_HEADER_SIZE + 9)
> +		return -EFAULT;
> +
> +	data = (void *)&rsp[TPM_HEADER_SIZE];
> +	if (be32_to_cpu(data->capability) != TPM2_CAP_HANDLES)
> +		return 0;
> +
> +	if (len != TPM_HEADER_SIZE + 9 + 4 * be32_to_cpu(data->count))
> +		return -EFAULT;
> +
> +	for (i = 0, j = 0; i < be32_to_cpu(data->count); i++) {
> +		phandle = be32_to_cpup((__be32 *)&data->handles[i]);
> +		phandle_type = phandle & 0xFF000000;
> +
> +		switch (phandle_type) {
> +		case TPM2_HT_TRANSIENT:
> +			vhandle = tpm2_map_to_vhandle(space, phandle, false);
> +			if (!vhandle)
> +				break;
> +
> +			data->handles[j] = cpu_to_be32(vhandle);
> +			j++;
> +			break;
> +		case TPM2_HT_HMAC_SESSION:
> +		case TPM2_HT_POLICY_SESSION:
> +			data->handles[j] = cpu_to_be32(phandle);
> +			j++;
> +			break;
> +		default:
> +			dev_err(&chip->dev, "%s: unknown handle 0x%08X\n",
> +				__func__, phandle);
> +			break;
> +		}
> +
> +	}
> +
> +	header->length = cpu_to_be32(TPM_HEADER_SIZE + 9 + 4 * j);
> +	data->count = cpu_to_be32(j);
> +	return 0;
> +}
> +
> +static int tpm2_save_space(struct tpm_chip *chip)
> +{
> +	struct tpm_space *space = &chip->work_space;
> +	unsigned int offset;
> +	int i;
> +	int rc;
> +
> +	for (i = 0, offset = 0; i < ARRAY_SIZE(space->context_tbl); i++) {
> +		if (!(space->context_tbl[i] && ~space->context_tbl[i]))
> +			continue;
> +
> +		rc = tpm2_save_context(chip, space->context_tbl[i],
> +				       space->context_buf, PAGE_SIZE,
> +				       &offset);
> +		if (rc == -ENOENT) {
> +			space->context_tbl[i] = 0;
> +			continue;
> +		} else if (rc)
> +			return rc;
> +
> +		space->context_tbl[i] = ~0;
> +	}
> +
> +	return 0;
> +}
> +
> +int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space,
> +		      u32 cc, u8 *buf, size_t *bufsiz)
> +{
> +	struct tpm_output_header *header = (void *)buf;
> +	int rc;
> +
> +	if (!space)
> +		return 0;
> +
> +	rc = tpm2_map_response_header(chip, cc, buf, *bufsiz);
> +	if (rc) {
> +		tpm2_flush_space(chip);
> +		return rc;
> +	}
> +
> +	rc = tpm2_map_response_body(chip, cc, buf, *bufsiz);
> +	if (rc) {
> +		tpm2_flush_space(chip);
> +		return rc;
> +	}
> +
> +	rc = tpm2_save_space(chip);
> +	if (rc) {
> +		tpm2_flush_space(chip);
> +		return rc;
> +	}
> +
> +	*bufsiz = be32_to_cpu(header->length);
> +
> +	memcpy(&space->context_tbl, &chip->work_space.context_tbl,
> +	       sizeof(space->context_tbl));
> +	memcpy(space->context_buf, chip->work_space.context_buf, PAGE_SIZE);
> +
> +	return 0;
> +}
>


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Ken Goldman Feb. 22, 2017, 5:08 p.m.
On 2/21/2017 1:24 PM, Nayna wrote:
>
> [snip]
>>
>> 1. Take locks.
>> 2. Load transient objects from the backing storage by using ContextLoad
>>     and map virtual handles to physical handles.
>> 3. Perform the transaction.
>> 4. Save transient objects to backing storage by using ContextSave and
>>     map resulting physical handle to virtual handle if there is such.
>>
>> This commit does not implement virtualization support for hmac and
>> policy sessions.
>>
>
> If I have understood discussions correctly, I assume, that kernel TPM
> operations will also be routed via RM. And I think that is not happening
> now with these patches.

There is one corner case that requires kernel operations to go through
the RM, and that's the session context regapping.  If the kernel did not 
go through the RM, it could not handle TPM_RC_CONTEXT_GAP.

I believe that kernel operations such as PCR extend, that don't require
sessions, do not have to go through the RM.

Kernel operations that use objects perhaps can bypass the RM as long as 
there is a lock and the kernel also context saves objects and returns 
the TPM to the empty state before it releases the lock.

Finally, I suspect that the RM should reserve 3 sessions for kernel
operations, so the kernel can't block because user space applications 
have filled all the session slots.


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James Bottomley Feb. 22, 2017, 5:39 p.m.
On Tue, 2017-02-21 at 23:54 +0530, Nayna wrote:
> 
> On 02/17/2017 12:55 AM, Jarkko Sakkinen wrote:
> > Added an ability to virtualize TPM commands into an isolated 
> > context that we call a TPM space because the word context is 
> > already heavily used in the TPM specification. Both the handle 
> > areas and bodies (where necessary) are virtualized.
> > 
> > The mechanism works by adding a new parameter struct tpm_space to 
> > the tpm_transmit() function. This new structure contains the list 
> > of virtual handles and a buffer of page size (currently) for
> > backing storage.
> > 
> > When tpm_transmit() is called with a struct tpm_space instance it 
> > will execute the following sequence:
> > 
> > 1. Take locks.
> > 2. Load transient objects from the backing storage by using
> > ContextLoad
> >     and map virtual handles to physical handles.
> > 3. Perform the transaction.
> > 4. Save transient objects to backing storage by using ContextSave
> > and
> >     map resulting physical handle to virtual handle if there is
> > such.
> > 
> > This commit does not implement virtualization support for hmac and
> > policy sessions.
> > 
> 
> If I have understood discussions correctly, I assume, that kernel TPM
> operations will also be routed via RM. And I think that is not 
> happening now with these patches.
> 
> Am I missing something ?

Right at the moment the kernel use of tpm2 looks like

acquire chip->tpm_mutex
load key
process key
unload key
release chip->tpm_mutex

While it does this, there's no need for it to have a RM interface
because what it does between the acquisition and drop of the mutex
can't be seen by or have any effect on userspace (whether it uses the
RM or not).  So currently, the question doesn't arise, which is the
situation you see.

When the kernel needs to use resources that persisted beyond it
dropping the chip->tpm_mutex (say using policy or audit sessions), then
it would need to become a customer of the RM.

James


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Ken Goldman Feb. 22, 2017, 8:56 p.m.
On 2/22/2017 12:39 PM, James Bottomley wrote:
>
> Right at the moment the kernel use of tpm2 looks like
>
> acquire chip->tpm_mutex
> load key
> process key
> unload key
> release chip->tpm_mutex

The advantage to context save/ context load over load / flush
is that load requires the parent(s).  The parent chain may be long,
a parent may require authorization, or authorization may be impossible 
because PCRs are no longer in the correct state.

In TPM 1.2, there was a performance difference because load was an 
asymmetric key operation, but it's symmetric in TPM 2.0.

> When the kernel needs to use resources that persisted beyond it
> dropping the chip->tpm_mutex (say using policy or audit sessions),
> then it would need to become a customer of the RM.

BTW, use of an EK private key requires a policy session.




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Jarkko Sakkinen Feb. 22, 2017, 9:08 p.m.
On Tue, Feb 21, 2017 at 11:54:50PM +0530, Nayna wrote:
> 
> 
> On 02/17/2017 12:55 AM, Jarkko Sakkinen wrote:
> > Added an ability to virtualize TPM commands into an isolated context
> > that we call a TPM space because the word context is already heavily
> > used in the TPM specification. Both the handle areas and bodies (where
> > necessary) are virtualized.
> > 
> > The mechanism works by adding a new parameter struct tpm_space to the
> > tpm_transmit() function. This new structure contains the list of virtual
> > handles and a buffer of page size (currently) for backing storage.
> > 
> > When tpm_transmit() is called with a struct tpm_space instance it will
> > execute the following sequence:
> > 
> > 1. Take locks.
> > 2. Load transient objects from the backing storage by using ContextLoad
> >     and map virtual handles to physical handles.
> > 3. Perform the transaction.
> > 4. Save transient objects to backing storage by using ContextSave and
> >     map resulting physical handle to virtual handle if there is such.
> > 
> > This commit does not implement virtualization support for hmac and
> > policy sessions.
> > 
> 
> If I have understood discussions correctly, I assume, that kernel TPM
> operations will also be routed via RM. And I think that is not happening now
> with these patches.
> 
> Am I missing something ?
> 
> Thanks & Regards,
>    - Nayna

Nope. It's not in the scope of this patch set and there are not
kernel use cases at the moment that would require it.

/Jarkko

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James Bottomley Feb. 24, 2017, 12:53 p.m.
On Thu, 2017-02-16 at 21:25 +0200, Jarkko Sakkinen wrote:
> Added an ability to virtualize TPM commands into an isolated context
> that we call a TPM space because the word context is already heavily
> used in the TPM specification. Both the handle areas and bodies
> (where
> necessary) are virtualized.
> 
> The mechanism works by adding a new parameter struct tpm_space to the
> tpm_transmit() function. This new structure contains the list of
> virtual
> handles and a buffer of page size (currently) for backing storage.
> 
> When tpm_transmit() is called with a struct tpm_space instance it
> will
> execute the following sequence:
> 
> 1. Take locks.
> 2. Load transient objects from the backing storage by using
> ContextLoad
>    and map virtual handles to physical handles.
> 3. Perform the transaction.
> 4. Save transient objects to backing storage by using ContextSave and
>    map resulting physical handle to virtual handle if there is such.
> 
> This commit does not implement virtualization support for hmac and
> policy sessions.
> 
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

For patches 1-4 you can add 

Reviewed-by: James Bottomley <James.Bottomley@HansenPartnership.com>

Just re-running a build with the latest kernel for my laptop to add
tested by.

James



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Jarkko Sakkinen Feb. 24, 2017, 5:02 p.m.
On Fri, Feb 24, 2017 at 07:53:22AM -0500, James Bottomley wrote:
> On Thu, 2017-02-16 at 21:25 +0200, Jarkko Sakkinen wrote:
> > Added an ability to virtualize TPM commands into an isolated context
> > that we call a TPM space because the word context is already heavily
> > used in the TPM specification. Both the handle areas and bodies
> > (where
> > necessary) are virtualized.
> > 
> > The mechanism works by adding a new parameter struct tpm_space to the
> > tpm_transmit() function. This new structure contains the list of
> > virtual
> > handles and a buffer of page size (currently) for backing storage.
> > 
> > When tpm_transmit() is called with a struct tpm_space instance it
> > will
> > execute the following sequence:
> > 
> > 1. Take locks.
> > 2. Load transient objects from the backing storage by using
> > ContextLoad
> >    and map virtual handles to physical handles.
> > 3. Perform the transaction.
> > 4. Save transient objects to backing storage by using ContextSave and
> >    map resulting physical handle to virtual handle if there is such.
> > 
> > This commit does not implement virtualization support for hmac and
> > policy sessions.
> > 
> > Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> 
> For patches 1-4 you can add 
> 
> Reviewed-by: James Bottomley <James.Bottomley@HansenPartnership.com>
> 
> Just re-running a build with the latest kernel for my laptop to add
> tested by.
> 
> James

Thank you!

/Jarkko

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Ken Goldman March 22, 2017, 8:09 p.m.
On 2/22/2017 12:39 PM, James Bottomley wrote:
>
> Right at the moment the kernel use of tpm2 looks like
>
> acquire chip->tpm_mutex
> load key
> process key
> unload key
> release chip->tpm_mutex
>
> While it does this, there's no need for it to have a RM interface
> because what it does between the acquisition and drop of the mutex
> can't be seen by or have any effect on userspace (whether it uses the
> RM or not).  So currently, the question doesn't arise, which is the
> situation you see.

1 - This appears to depend on the RM not releasing the mutex until all 
objects are swapped out.  Correct?  Same for sessions?

2 - A startauthsession can cause a regap error.  Does the above depend 
on the RM doing early regapping so the RM won't see that error?

3 - There's also the problem where the TPM saved session slots 
(typically 64) are full.  My intuition is that the best solution is for 
the RM to reserve 3 slots for the kernel.



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Jarkko Sakkinen March 23, 2017, 3:56 p.m.
On Wed, Mar 22, 2017 at 04:09:21PM -0400, Ken Goldman wrote:
> On 2/22/2017 12:39 PM, James Bottomley wrote:
> > 
> > Right at the moment the kernel use of tpm2 looks like
> > 
> > acquire chip->tpm_mutex
> > load key
> > process key
> > unload key
> > release chip->tpm_mutex
> > 
> > While it does this, there's no need for it to have a RM interface
> > because what it does between the acquisition and drop of the mutex
> > can't be seen by or have any effect on userspace (whether it uses the
> > RM or not).  So currently, the question doesn't arise, which is the
> > situation you see.
> 
> 1 - This appears to depend on the RM not releasing the mutex until all
> objects are swapped out.  Correct?  Same for sessions?

Yes.

> 2 - A startauthsession can cause a regap error.  Does the above depend on
> the RM doing early regapping so the RM won't see that error?

We are not trying to resolve that for 4.12. It can happen.

> 3 - There's also the problem where the TPM saved session slots (typically
> 64) are full.  My intuition is that the best solution is for the RM to
> reserve 3 slots for the kernel.

Maybe but at the moment kernel does not use sessions.

/Jarkko

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Patch hide | download patch | download mbox

diff --git a/drivers/char/tpm/Makefile b/drivers/char/tpm/Makefile
index 3d386a8..8f07fcf 100644
--- a/drivers/char/tpm/Makefile
+++ b/drivers/char/tpm/Makefile
@@ -3,7 +3,7 @@ 
 #
 obj-$(CONFIG_TCG_TPM) += tpm.o
 tpm-y := tpm-interface.o tpm-dev.o tpm-sysfs.o tpm-chip.o tpm2-cmd.o \
-		tpm1_eventlog.o tpm2_eventlog.o
+	 tpm1_eventlog.o tpm2_eventlog.o tpm2-space.o
 tpm-$(CONFIG_ACPI) += tpm_ppi.o tpm_acpi.o
 tpm-$(CONFIG_OF) += tpm_of.o
 obj-$(CONFIG_TCG_TIS_CORE) += tpm_tis_core.o
diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index c406343..993b9ae 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -128,6 +128,7 @@  static void tpm_dev_release(struct device *dev)
 	mutex_unlock(&idr_lock);
 
 	kfree(chip->log.bios_event_log);
+	kfree(chip->work_space.context_buf);
 	kfree(chip);
 }
 
@@ -189,6 +190,12 @@  struct tpm_chip *tpm_chip_alloc(struct device *pdev,
 	chip->cdev.owner = THIS_MODULE;
 	chip->cdev.kobj.parent = &chip->dev.kobj;
 
+	chip->work_space.context_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!chip->work_space.context_buf) {
+		rc = -ENOMEM;
+		goto out;
+	}
+
 	return chip;
 
 out:
diff --git a/drivers/char/tpm/tpm-dev.c b/drivers/char/tpm/tpm-dev.c
index 02a8850..414553b 100644
--- a/drivers/char/tpm/tpm-dev.c
+++ b/drivers/char/tpm/tpm-dev.c
@@ -147,7 +147,7 @@  static ssize_t tpm_write(struct file *file, const char __user *buf,
 		mutex_unlock(&priv->buffer_mutex);
 		return -EPIPE;
 	}
-	out_size = tpm_transmit(priv->chip, priv->data_buffer,
+	out_size = tpm_transmit(priv->chip, NULL, priv->data_buffer,
 				sizeof(priv->data_buffer), 0);
 
 	tpm_put_ops(priv->chip);
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 20b1fe3..db5ffe9 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -376,11 +376,12 @@  static bool tpm_validate_command(struct tpm_chip *chip, const u8 *cmd,
  *     0 when the operation is successful.
  *     A negative number for system errors (errno).
  */
-ssize_t tpm_transmit(struct tpm_chip *chip, const u8 *buf, size_t bufsiz,
-		     unsigned int flags)
+ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space,
+		     u8 *buf, size_t bufsiz, unsigned int flags)
 {
-	const struct tpm_output_header *header = (void *)buf;
-	ssize_t rc;
+	struct tpm_output_header *header = (void *)buf;
+	int rc;
+	ssize_t len = 0;
 	u32 count, ordinal;
 	unsigned long stop;
 
@@ -406,10 +407,14 @@  ssize_t tpm_transmit(struct tpm_chip *chip, const u8 *buf, size_t bufsiz,
 	if (chip->dev.parent)
 		pm_runtime_get_sync(chip->dev.parent);
 
+	rc = tpm2_prepare_space(chip, space, ordinal, buf);
+	if (rc)
+		goto out;
+
 	rc = chip->ops->send(chip, (u8 *) buf, count);
 	if (rc < 0) {
 		dev_err(&chip->dev,
-			"tpm_transmit: tpm_send: error %zd\n", rc);
+			"tpm_transmit: tpm_send: error %d\n", rc);
 		goto out;
 	}
 
@@ -442,18 +447,23 @@  ssize_t tpm_transmit(struct tpm_chip *chip, const u8 *buf, size_t bufsiz,
 	goto out;
 
 out_recv:
-	rc = chip->ops->recv(chip, (u8 *) buf, bufsiz);
-	if (rc < 0) {
+	len = chip->ops->recv(chip, (u8 *) buf, bufsiz);
+	if (len < 0) {
 		dev_err(&chip->dev,
-			"tpm_transmit: tpm_recv: error %zd\n", rc);
+			"tpm_transmit: tpm_recv: error %d\n", rc);
+		rc = len;
 		goto out;
-	} else if (rc < TPM_HEADER_SIZE) {
+	} else if (len < TPM_HEADER_SIZE) {
 		rc = -EFAULT;
 		goto out;
 	}
 
-	if (rc != be32_to_cpu(header->length))
+	if (len != be32_to_cpu(header->length)) {
+		rc = -EFAULT;
 		goto out;
+	}
+
+	rc = tpm2_commit_space(chip, space, ordinal, buf, &len);
 
 out:
 	if (chip->dev.parent)
@@ -461,7 +471,7 @@  ssize_t tpm_transmit(struct tpm_chip *chip, const u8 *buf, size_t bufsiz,
 
 	if (!(flags & TPM_TRANSMIT_UNLOCKED))
 		mutex_unlock(&chip->tpm_mutex);
-	return rc;
+	return rc ? rc : len;
 }
 
 /**
@@ -480,15 +490,16 @@  ssize_t tpm_transmit(struct tpm_chip *chip, const u8 *buf, size_t bufsiz,
  *     A negative number for system errors (errno).
  *     A positive number for a TPM error.
  */
-ssize_t tpm_transmit_cmd(struct tpm_chip *chip, const void *buf,
-			 size_t bufsiz, size_t min_rsp_body_length,
-			 unsigned int flags, const char *desc)
+ssize_t tpm_transmit_cmd(struct tpm_chip *chip, struct tpm_space *space,
+			 const void *buf, size_t bufsiz,
+			 size_t min_rsp_body_length, unsigned int flags,
+			 const char *desc)
 {
 	const struct tpm_output_header *header = buf;
 	int err;
 	ssize_t len;
 
-	len = tpm_transmit(chip, (const u8 *)buf, bufsiz, flags);
+	len = tpm_transmit(chip, space, (u8 *)buf, bufsiz, flags);
 	if (len <  0)
 		return len;
 
@@ -541,7 +552,7 @@  ssize_t tpm_getcap(struct tpm_chip *chip, u32 subcap_id, cap_t *cap,
 		tpm_cmd.params.getcap_in.subcap_size = cpu_to_be32(4);
 		tpm_cmd.params.getcap_in.subcap = cpu_to_be32(subcap_id);
 	}
-	rc = tpm_transmit_cmd(chip, &tpm_cmd, TPM_INTERNAL_RESULT_SIZE,
+	rc = tpm_transmit_cmd(chip, NULL, &tpm_cmd, TPM_INTERNAL_RESULT_SIZE,
 			      min_cap_length, 0, desc);
 	if (!rc)
 		*cap = tpm_cmd.params.getcap_out.cap;
@@ -565,7 +576,8 @@  static int tpm_startup(struct tpm_chip *chip, __be16 startup_type)
 	start_cmd.header.in = tpm_startup_header;
 
 	start_cmd.params.startup_in.startup_type = startup_type;
-	return tpm_transmit_cmd(chip, &start_cmd, TPM_INTERNAL_RESULT_SIZE, 0,
+	return tpm_transmit_cmd(chip, NULL, &start_cmd,
+				TPM_INTERNAL_RESULT_SIZE, 0,
 				0, "attempting to start the TPM");
 }
 
@@ -722,8 +734,8 @@  static int tpm_continue_selftest(struct tpm_chip *chip)
 	struct tpm_cmd_t cmd;
 
 	cmd.header.in = continue_selftest_header;
-	rc = tpm_transmit_cmd(chip, &cmd, CONTINUE_SELFTEST_RESULT_SIZE, 0, 0,
-			      "continue selftest");
+	rc = tpm_transmit_cmd(chip, NULL, &cmd, CONTINUE_SELFTEST_RESULT_SIZE,
+			      0, 0, "continue selftest");
 	return rc;
 }
 
@@ -743,7 +755,7 @@  int tpm_pcr_read_dev(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
 
 	cmd.header.in = pcrread_header;
 	cmd.params.pcrread_in.pcr_idx = cpu_to_be32(pcr_idx);
-	rc = tpm_transmit_cmd(chip, &cmd, READ_PCR_RESULT_SIZE,
+	rc = tpm_transmit_cmd(chip, NULL, &cmd, READ_PCR_RESULT_SIZE,
 			      READ_PCR_RESULT_BODY_SIZE, 0,
 			      "attempting to read a pcr value");
 
@@ -855,7 +867,7 @@  int tpm_pcr_extend(u32 chip_num, int pcr_idx, const u8 *hash)
 	cmd.header.in = pcrextend_header;
 	cmd.params.pcrextend_in.pcr_idx = cpu_to_be32(pcr_idx);
 	memcpy(cmd.params.pcrextend_in.hash, hash, TPM_DIGEST_SIZE);
-	rc = tpm_transmit_cmd(chip, &cmd, EXTEND_PCR_RESULT_SIZE,
+	rc = tpm_transmit_cmd(chip, NULL, &cmd, EXTEND_PCR_RESULT_SIZE,
 			      EXTEND_PCR_RESULT_BODY_SIZE, 0,
 			      "attempting extend a PCR value");
 
@@ -960,8 +972,8 @@  int tpm_send(u32 chip_num, void *cmd, size_t buflen)
 	if (chip == NULL)
 		return -ENODEV;
 
-	rc = tpm_transmit_cmd(chip, cmd, buflen, 0, 0, "attempting tpm_cmd");
-
+	rc = tpm_transmit_cmd(chip, NULL, cmd, buflen, 0, 0,
+			      "attempting tpm_cmd");
 	tpm_put_ops(chip);
 	return rc;
 }
@@ -1062,16 +1074,16 @@  int tpm_pm_suspend(struct device *dev)
 		cmd.params.pcrextend_in.pcr_idx = cpu_to_be32(tpm_suspend_pcr);
 		memcpy(cmd.params.pcrextend_in.hash, dummy_hash,
 		       TPM_DIGEST_SIZE);
-		rc = tpm_transmit_cmd(chip, &cmd, EXTEND_PCR_RESULT_SIZE,
-				     EXTEND_PCR_RESULT_BODY_SIZE, 0,
+		rc = tpm_transmit_cmd(chip, NULL, &cmd, EXTEND_PCR_RESULT_SIZE,
+				      EXTEND_PCR_RESULT_BODY_SIZE, 0,
 				      "extending dummy pcr before suspend");
 	}
 
 	/* now do the actual savestate */
 	for (try = 0; try < TPM_RETRY; try++) {
 		cmd.header.in = savestate_header;
-		rc = tpm_transmit_cmd(chip, &cmd, SAVESTATE_RESULT_SIZE, 0,
-				      0, NULL);
+		rc = tpm_transmit_cmd(chip, NULL, &cmd, SAVESTATE_RESULT_SIZE,
+				      0, 0, NULL);
 
 		/*
 		 * If the TPM indicates that it is too busy to respond to
@@ -1154,7 +1166,7 @@  int tpm_get_random(u32 chip_num, u8 *out, size_t max)
 		tpm_cmd.header.in = tpm_getrandom_header;
 		tpm_cmd.params.getrandom_in.num_bytes = cpu_to_be32(num_bytes);
 
-		err = tpm_transmit_cmd(chip, &tpm_cmd,
+		err = tpm_transmit_cmd(chip, NULL, &tpm_cmd,
 				       TPM_GETRANDOM_RESULT_SIZE + num_bytes,
 				       offsetof(struct tpm_getrandom_out,
 						rng_data),
diff --git a/drivers/char/tpm/tpm-sysfs.c b/drivers/char/tpm/tpm-sysfs.c
index 2f596d7..55405db 100644
--- a/drivers/char/tpm/tpm-sysfs.c
+++ b/drivers/char/tpm/tpm-sysfs.c
@@ -40,7 +40,7 @@  static ssize_t pubek_show(struct device *dev, struct device_attribute *attr,
 	struct tpm_chip *chip = to_tpm_chip(dev);
 
 	tpm_cmd.header.in = tpm_readpubek_header;
-	err = tpm_transmit_cmd(chip, &tpm_cmd, READ_PUBEK_RESULT_SIZE,
+	err = tpm_transmit_cmd(chip, NULL, &tpm_cmd, READ_PUBEK_RESULT_SIZE,
 			       READ_PUBEK_RESULT_MIN_BODY_SIZE, 0,
 			       "attempting to read the PUBEK");
 	if (err)
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 0ec1cf0..97e48a4 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -89,10 +89,13 @@  enum tpm2_structures {
 };
 
 enum tpm2_return_codes {
+	TPM2_RC_SUCCESS		= 0x0000,
 	TPM2_RC_HASH		= 0x0083, /* RC_FMT1 */
+	TPM2_RC_HANDLE		= 0x008B,
 	TPM2_RC_INITIALIZE	= 0x0100, /* RC_VER1 */
 	TPM2_RC_DISABLED	= 0x0120,
 	TPM2_RC_TESTING		= 0x090A, /* RC_WARN */
+	TPM2_RC_REFERENCE_H0	= 0x0910,
 };
 
 enum tpm2_algorithms {
@@ -114,6 +117,7 @@  enum tpm2_command_codes {
 	TPM2_CC_CREATE		= 0x0153,
 	TPM2_CC_LOAD		= 0x0157,
 	TPM2_CC_UNSEAL		= 0x015E,
+	TPM2_CC_CONTEXT_LOAD	= 0x0161,
 	TPM2_CC_CONTEXT_SAVE	= 0x0162,
 	TPM2_CC_FLUSH_CONTEXT	= 0x0165,
 	TPM2_CC_GET_CAPABILITY	= 0x017A,
@@ -128,6 +132,7 @@  enum tpm2_permanent_handles {
 };
 
 enum tpm2_capabilities {
+	TPM2_CAP_HANDLES	= 1,
 	TPM2_CAP_COMMANDS	= 2,
 	TPM2_CAP_PCRS		= 5,
 	TPM2_CAP_TPM_PROPERTIES = 6,
@@ -153,6 +158,11 @@  enum tpm2_cc_attrs {
 
 #define TPM_PPI_VERSION_LEN		3
 
+struct tpm_space {
+	u32 context_tbl[3];
+	u8 *context_buf;
+};
+
 enum tpm_chip_flags {
 	TPM_CHIP_FLAG_TPM2		= BIT(1),
 	TPM_CHIP_FLAG_IRQ		= BIT(2),
@@ -211,6 +221,7 @@  struct tpm_chip {
 	char ppi_version[TPM_PPI_VERSION_LEN + 1];
 #endif /* CONFIG_ACPI */
 
+	struct tpm_space work_space;
 	u32 nr_commands;
 	u32 *cc_attrs_tbl;
 };
@@ -507,10 +518,11 @@  enum tpm_transmit_flags {
 	TPM_TRANSMIT_UNLOCKED	= BIT(0),
 };
 
-ssize_t tpm_transmit(struct tpm_chip *chip, const u8 *buf, size_t bufsiz,
-		     unsigned int flags);
-ssize_t tpm_transmit_cmd(struct tpm_chip *chip, const void *buf, size_t bufsiz,
-			 size_t min_rsp_body_len, unsigned int flags,
+ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space,
+		     u8 *buf, size_t bufsiz, unsigned int flags);
+ssize_t tpm_transmit_cmd(struct tpm_chip *chip, struct tpm_space *space,
+			 const void *buf, size_t bufsiz,
+			 size_t min_rsp_body_length, unsigned int flags,
 			 const char *desc);
 ssize_t tpm_getcap(struct tpm_chip *chip, u32 subcap_id, cap_t *cap,
 		   const char *desc, size_t min_cap_length);
@@ -572,4 +584,10 @@  unsigned long tpm2_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal);
 int tpm2_probe(struct tpm_chip *chip);
 ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip);
 int tpm2_find_cc(struct tpm_chip *chip, u32 cc);
+int tpm2_init_space(struct tpm_space *space);
+void tpm2_del_space(struct tpm_space *space);
+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);
 #endif
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 897902a..96121b3 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -266,7 +266,7 @@  int tpm2_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
 	       sizeof(cmd.params.pcrread_in.pcr_select));
 	cmd.params.pcrread_in.pcr_select[pcr_idx >> 3] = 1 << (pcr_idx & 0x7);
 
-	rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd),
+	rc = tpm_transmit_cmd(chip, NULL, &cmd, sizeof(cmd),
 			      TPM2_PCR_READ_RESP_BODY_SIZE,
 			      0, "attempting to read a pcr value");
 	if (rc == 0) {
@@ -333,7 +333,7 @@  int tpm2_pcr_extend(struct tpm_chip *chip, int pcr_idx, u32 count,
 		}
 	}
 
-	rc = tpm_transmit_cmd(chip, buf.data, PAGE_SIZE, 0, 0,
+	rc = tpm_transmit_cmd(chip, NULL, buf.data, PAGE_SIZE, 0, 0,
 			      "attempting extend a PCR value");
 
 	tpm_buf_destroy(&buf);
@@ -382,7 +382,7 @@  int tpm2_get_random(struct tpm_chip *chip, u8 *out, size_t max)
 		cmd.header.in = tpm2_getrandom_header;
 		cmd.params.getrandom_in.size = cpu_to_be16(num_bytes);
 
-		err = tpm_transmit_cmd(chip, &cmd, sizeof(cmd),
+		err = tpm_transmit_cmd(chip, NULL, &cmd, sizeof(cmd),
 				       offsetof(struct tpm2_get_random_out,
 						buffer),
 				       0, "attempting get random");
@@ -441,7 +441,7 @@  void tpm2_flush_context_cmd(struct tpm_chip *chip, u32 handle,
 
 	tpm_buf_append_u32(&buf, handle);
 
-	(void) tpm_transmit_cmd(chip, buf.data, PAGE_SIZE, 0, flags,
+	(void) tpm_transmit_cmd(chip, NULL, buf.data, PAGE_SIZE, 0, flags,
 				"flushing context");
 
 	tpm_buf_destroy(&buf);
@@ -557,7 +557,7 @@  int tpm2_seal_trusted(struct tpm_chip *chip,
 		goto out;
 	}
 
-	rc = tpm_transmit_cmd(chip, buf.data, PAGE_SIZE, 4, 0,
+	rc = tpm_transmit_cmd(chip, NULL, buf.data, PAGE_SIZE, 4, 0,
 			      "sealing data");
 	if (rc)
 		goto out;
@@ -641,7 +641,7 @@  static int tpm2_load_cmd(struct tpm_chip *chip,
 		goto out;
 	}
 
-	rc = tpm_transmit_cmd(chip, buf.data, PAGE_SIZE, 4, flags,
+	rc = tpm_transmit_cmd(chip, NULL, buf.data, PAGE_SIZE, 4, flags,
 			      "loading blob");
 	if (!rc)
 		*blob_handle = be32_to_cpup(
@@ -693,7 +693,7 @@  static int tpm2_unseal_cmd(struct tpm_chip *chip,
 			     options->blobauth /* hmac */,
 			     TPM_DIGEST_SIZE);
 
-	rc = tpm_transmit_cmd(chip, buf.data, PAGE_SIZE, 6, flags,
+	rc = tpm_transmit_cmd(chip, NULL, buf.data, PAGE_SIZE, 6, flags,
 			      "unsealing");
 	if (rc > 0)
 		rc = -EPERM;
@@ -770,7 +770,7 @@  ssize_t tpm2_get_tpm_pt(struct tpm_chip *chip, u32 property_id,  u32 *value,
 	cmd.params.get_tpm_pt_in.property_id = cpu_to_be32(property_id);
 	cmd.params.get_tpm_pt_in.property_cnt = cpu_to_be32(1);
 
-	rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd),
+	rc = tpm_transmit_cmd(chip, NULL, &cmd, sizeof(cmd),
 			      TPM2_GET_TPM_PT_OUT_BODY_SIZE, 0, desc);
 	if (!rc)
 		*value = be32_to_cpu(cmd.params.get_tpm_pt_out.value);
@@ -805,7 +805,7 @@  static int tpm2_startup(struct tpm_chip *chip, u16 startup_type)
 	cmd.header.in = tpm2_startup_header;
 
 	cmd.params.startup_in.startup_type = cpu_to_be16(startup_type);
-	return tpm_transmit_cmd(chip, &cmd, sizeof(cmd), 0, 0,
+	return tpm_transmit_cmd(chip, NULL, &cmd, sizeof(cmd), 0, 0,
 				"attempting to start the TPM");
 }
 
@@ -834,7 +834,7 @@  void tpm2_shutdown(struct tpm_chip *chip, u16 shutdown_type)
 	cmd.header.in = tpm2_shutdown_header;
 	cmd.params.startup_in.startup_type = cpu_to_be16(shutdown_type);
 
-	rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd), 0, 0,
+	rc = tpm_transmit_cmd(chip, NULL, &cmd, sizeof(cmd), 0, 0,
 			      "stopping the TPM");
 
 	/* In places where shutdown command is sent there's no much we can do
@@ -898,7 +898,7 @@  static int tpm2_start_selftest(struct tpm_chip *chip, bool full)
 	cmd.header.in = tpm2_selftest_header;
 	cmd.params.selftest_in.full_test = full;
 
-	rc = tpm_transmit_cmd(chip, &cmd, TPM2_SELF_TEST_IN_SIZE, 0, 0,
+	rc = tpm_transmit_cmd(chip, NULL, &cmd, TPM2_SELF_TEST_IN_SIZE, 0, 0,
 			      "continue selftest");
 
 	/* At least some prototype chips seem to give RC_TESTING error
@@ -949,7 +949,8 @@  static int tpm2_do_selftest(struct tpm_chip *chip)
 		cmd.params.pcrread_in.pcr_select[1] = 0x00;
 		cmd.params.pcrread_in.pcr_select[2] = 0x00;
 
-		rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd), 0, 0, NULL);
+		rc = tpm_transmit_cmd(chip, NULL, &cmd, sizeof(cmd), 0, 0,
+				      NULL);
 		if (rc < 0)
 			break;
 
@@ -982,7 +983,7 @@  int tpm2_probe(struct tpm_chip *chip)
 	cmd.params.get_tpm_pt_in.property_id = cpu_to_be32(0x100);
 	cmd.params.get_tpm_pt_in.property_cnt = cpu_to_be32(1);
 
-	rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd), 0, 0, NULL);
+	rc = tpm_transmit_cmd(chip, NULL, &cmd, sizeof(cmd), 0, 0, NULL);
 	if (rc <  0)
 		return rc;
 
@@ -1022,8 +1023,8 @@  static int tpm2_get_cc_attrs_tbl(struct tpm_chip *chip)
 	tpm_buf_append_u32(&buf, TPM2_CC_FIRST);
 	tpm_buf_append_u32(&buf, nr_commands);
 
-	rc = tpm_transmit_cmd(chip, buf.data, PAGE_SIZE, 9 + 4 * nr_commands,
-			      0, NULL);
+	rc = tpm_transmit_cmd(chip, NULL, buf.data, PAGE_SIZE,
+			      9 + 4 * nr_commands, 0, NULL);
 	if (rc) {
 		tpm_buf_destroy(&buf);
 		goto out;
@@ -1136,7 +1137,7 @@  ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip)
 	tpm_buf_append_u32(&buf, 0);
 	tpm_buf_append_u32(&buf, 1);
 
-	rc = tpm_transmit_cmd(chip, buf.data, PAGE_SIZE, 9, 0,
+	rc = tpm_transmit_cmd(chip, NULL, buf.data, PAGE_SIZE, 9, 0,
 			      "get tpm pcr allocation");
 	if (rc)
 		goto out;
diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
new file mode 100644
index 0000000..e955548
--- /dev/null
+++ b/drivers/char/tpm/tpm2-space.c
@@ -0,0 +1,431 @@ 
+/*
+ * Copyright (C) 2016 Intel Corporation
+ *
+ * Authors:
+ * Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
+ *
+ * Maintained by: <tpmdd-devel@lists.sourceforge.net>
+ *
+ * This file contains TPM2 protocol implementations of the commands
+ * used by the kernel internally.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; version 2
+ * of the License.
+ */
+
+#include <linux/gfp.h>
+#include <asm/unaligned.h>
+#include "tpm.h"
+
+enum tpm2_handle_types {
+	TPM2_HT_HMAC_SESSION	= 0x02000000,
+	TPM2_HT_POLICY_SESSION	= 0x03000000,
+	TPM2_HT_TRANSIENT	= 0x80000000,
+};
+
+struct tpm2_context {
+	__be64 sequence;
+	__be32 saved_handle;
+	__be32 hierarchy;
+	__be16 blob_size;
+} __packed;
+
+int tpm2_init_space(struct tpm_space *space)
+{
+	space->context_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!space->context_buf)
+		return -ENOMEM;
+
+	return 0;
+}
+
+void tpm2_del_space(struct tpm_space *space)
+{
+	kfree(space->context_buf);
+}
+
+static int tpm2_load_context(struct tpm_chip *chip, u8 *buf,
+			     unsigned int *offset, u32 *handle)
+{
+	struct tpm_buf tbuf;
+	struct tpm2_context *ctx;
+	unsigned int body_size;
+	int rc;
+
+	rc = tpm_buf_init(&tbuf, TPM2_ST_NO_SESSIONS, TPM2_CC_CONTEXT_LOAD);
+	if (rc)
+		return rc;
+
+	ctx = (struct tpm2_context *)&buf[*offset];
+	body_size = sizeof(*ctx) + be16_to_cpu(ctx->blob_size);
+	tpm_buf_append(&tbuf, &buf[*offset], body_size);
+
+	rc = tpm_transmit_cmd(chip, NULL, tbuf.data, PAGE_SIZE, 4,
+			      TPM_TRANSMIT_UNLOCKED, NULL);
+	if (rc < 0) {
+		dev_warn(&chip->dev, "%s: failed with a system error %d\n",
+			 __func__, rc);
+		tpm_buf_destroy(&tbuf);
+		return -EFAULT;
+	} else if (rc > 0) {
+		dev_warn(&chip->dev, "%s: failed with a TPM error 0x%04X\n",
+			 __func__, rc);
+		tpm_buf_destroy(&tbuf);
+		return -EFAULT;
+	}
+
+	*handle = be32_to_cpup((__be32 *)&tbuf.data[TPM_HEADER_SIZE]);
+	*offset += body_size;
+
+	tpm_buf_destroy(&tbuf);
+	return 0;
+}
+
+static int tpm2_save_context(struct tpm_chip *chip, u32 handle, u8 *buf,
+			     unsigned int buf_size, unsigned int *offset)
+{
+	struct tpm_buf tbuf;
+	unsigned int body_size;
+	int rc;
+
+	rc = tpm_buf_init(&tbuf, TPM2_ST_NO_SESSIONS, TPM2_CC_CONTEXT_SAVE);
+	if (rc)
+		return rc;
+
+	tpm_buf_append_u32(&tbuf, handle);
+
+	rc = tpm_transmit_cmd(chip, NULL, tbuf.data, PAGE_SIZE, 0,
+			      TPM_TRANSMIT_UNLOCKED, NULL);
+	if (rc < 0) {
+		dev_warn(&chip->dev, "%s: failed with a system error %d\n",
+			 __func__, rc);
+		tpm_buf_destroy(&tbuf);
+		return -EFAULT;
+	} else if (tpm2_rc_value(rc) == TPM2_RC_REFERENCE_H0) {
+		tpm_buf_destroy(&tbuf);
+		return -ENOENT;
+	} else if (rc) {
+		dev_warn(&chip->dev, "%s: failed with a TPM error 0x%04X\n",
+			 __func__, rc);
+		tpm_buf_destroy(&tbuf);
+		return -EFAULT;
+	}
+
+	body_size = tpm_buf_length(&tbuf) - TPM_HEADER_SIZE;
+	if ((*offset + body_size) > buf_size) {
+		dev_warn(&chip->dev, "%s: out of backing storage\n", __func__);
+		tpm_buf_destroy(&tbuf);
+		return -ENOMEM;
+	}
+
+	memcpy(&buf[*offset], &tbuf.data[TPM_HEADER_SIZE], body_size);
+	tpm2_flush_context_cmd(chip, handle, TPM_TRANSMIT_UNLOCKED);
+	*offset += body_size;
+	tpm_buf_destroy(&tbuf);
+	return 0;
+}
+
+static void tpm2_flush_space(struct tpm_chip *chip)
+{
+	struct tpm_space *space = &chip->work_space;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(space->context_tbl); i++)
+		if (space->context_tbl[i] && ~space->context_tbl[i])
+			tpm2_flush_context_cmd(chip, space->context_tbl[i],
+					       TPM_TRANSMIT_UNLOCKED);
+}
+
+static int tpm2_load_space(struct tpm_chip *chip)
+{
+	struct tpm_space *space = &chip->work_space;
+	unsigned int offset;
+	int i;
+	int rc;
+
+	for (i = 0, offset = 0; i < ARRAY_SIZE(space->context_tbl); i++) {
+		if (!space->context_tbl[i])
+			continue;
+
+		/* sanity check, should never happen */
+		if (~space->context_tbl[i]) {
+			dev_err(&chip->dev, "context table is inconsistent");
+			return -EFAULT;
+		}
+
+		rc = tpm2_load_context(chip, space->context_buf, &offset,
+				       &space->context_tbl[i]);
+		if (rc)
+			return rc;
+	}
+
+	return 0;
+}
+
+static bool tpm2_map_to_phandle(struct tpm_space *space, void *handle)
+{
+	u32 vhandle = be32_to_cpup((__be32 *)handle);
+	u32 phandle;
+	int i;
+
+	i = 0xFFFFFF - (vhandle & 0xFFFFFF);
+	if (i > ARRAY_SIZE(space->context_tbl) || !space->context_tbl[i])
+		return false;
+
+	phandle = space->context_tbl[i];
+	*((__be32 *)handle) = cpu_to_be32(phandle);
+	return true;
+}
+
+static int tpm2_map_command(struct tpm_chip *chip, u32 cc, u8 *cmd)
+{
+	struct tpm_space *space = &chip->work_space;
+	unsigned int nr_handles;
+	u32 attrs;
+	u32 *handle;
+	int i;
+
+	i = tpm2_find_cc(chip, cc);
+	if (i < 0)
+		return -EINVAL;
+
+	attrs = chip->cc_attrs_tbl[i];
+	nr_handles = (attrs >> TPM2_CC_ATTR_CHANDLES) & GENMASK(2, 0);
+
+	handle = (u32 *)&cmd[TPM_HEADER_SIZE];
+	for (i = 0; i < nr_handles; i++, handle++) {
+		if ((be32_to_cpu(*handle) & 0xFF000000) == TPM2_HT_TRANSIENT) {
+			if (!tpm2_map_to_phandle(space, handle))
+				return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u32 cc,
+		       u8 *cmd)
+{
+	int rc;
+
+	if (!space)
+		return 0;
+
+	memcpy(&chip->work_space.context_tbl, &space->context_tbl,
+	       sizeof(space->context_tbl));
+	memcpy(chip->work_space.context_buf, space->context_buf, PAGE_SIZE);
+
+	rc = tpm2_load_space(chip);
+	if (rc) {
+		tpm2_flush_space(chip);
+		return rc;
+	}
+
+	rc = tpm2_map_command(chip, cc, cmd);
+	if (rc) {
+		tpm2_flush_space(chip);
+		return rc;
+	}
+
+	return 0;
+}
+
+static u32 tpm2_map_to_vhandle(struct tpm_space *space, u32 phandle, bool alloc)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(space->context_tbl); i++) {
+		if (alloc) {
+			if (!space->context_tbl[i]) {
+				space->context_tbl[i] = phandle;
+				break;
+			}
+		} else if (space->context_tbl[i] == phandle)
+			break;
+	}
+
+	if (i == ARRAY_SIZE(space->context_tbl))
+		return 0;
+
+	return TPM2_HT_TRANSIENT | (0xFFFFFF - i);
+}
+
+static int tpm2_map_response_header(struct tpm_chip *chip, u32 cc, u8 *rsp,
+				    size_t len)
+{
+	struct tpm_space *space = &chip->work_space;
+	struct tpm_output_header *header = (void *)rsp;
+	u32 phandle;
+	u32 phandle_type;
+	u32 vhandle;
+	u32 attrs;
+	int i;
+
+	if (be32_to_cpu(header->return_code) != TPM2_RC_SUCCESS)
+		return 0;
+
+	i = tpm2_find_cc(chip, cc);
+	/* sanity check, should never happen */
+	if (i < 0)
+		return -EFAULT;
+
+	attrs = chip->cc_attrs_tbl[i];
+	if (!((attrs >> TPM2_CC_ATTR_RHANDLE) & 1))
+		return 0;
+
+	phandle = be32_to_cpup((__be32 *)&rsp[TPM_HEADER_SIZE]);
+	phandle_type = phandle & 0xFF000000;
+
+	switch (phandle_type) {
+	case TPM2_HT_TRANSIENT:
+		vhandle = tpm2_map_to_vhandle(space, phandle, true);
+		if (!vhandle)
+			goto out_no_slots;
+
+		*(__be32 *)&rsp[TPM_HEADER_SIZE] = cpu_to_be32(vhandle);
+		break;
+	case TPM2_HT_HMAC_SESSION:
+	case TPM2_HT_POLICY_SESSION:
+		break;
+	default:
+		dev_err(&chip->dev, "%s: unknown handle 0x%08X\n",
+			__func__, phandle);
+		break;
+	};
+
+	return 0;
+out_no_slots:
+	tpm2_flush_context_cmd(chip, phandle, TPM_TRANSMIT_UNLOCKED);
+	dev_warn(&chip->dev, "%s: out of slots for 0x%08X\n", __func__,
+		 phandle);
+	return -ENOMEM;
+}
+
+struct tpm2_cap_handles {
+	u8 more_data;
+	__be32 capability;
+	__be32 count;
+	__be32 handles[];
+} __packed;
+
+static int tpm2_map_response_body(struct tpm_chip *chip, u32 cc, u8 *rsp,
+				  size_t len)
+{
+	struct tpm_space *space = &chip->work_space;
+	struct tpm_output_header *header = (void *)rsp;
+	struct tpm2_cap_handles *data;
+	u32 phandle;
+	u32 phandle_type;
+	u32 vhandle;
+	int i;
+	int j;
+
+	if (cc != TPM2_CC_GET_CAPABILITY ||
+	    be32_to_cpu(header->return_code) != TPM2_RC_SUCCESS) {
+		return 0;
+	}
+
+	if (len < TPM_HEADER_SIZE + 9)
+		return -EFAULT;
+
+	data = (void *)&rsp[TPM_HEADER_SIZE];
+	if (be32_to_cpu(data->capability) != TPM2_CAP_HANDLES)
+		return 0;
+
+	if (len != TPM_HEADER_SIZE + 9 + 4 * be32_to_cpu(data->count))
+		return -EFAULT;
+
+	for (i = 0, j = 0; i < be32_to_cpu(data->count); i++) {
+		phandle = be32_to_cpup((__be32 *)&data->handles[i]);
+		phandle_type = phandle & 0xFF000000;
+
+		switch (phandle_type) {
+		case TPM2_HT_TRANSIENT:
+			vhandle = tpm2_map_to_vhandle(space, phandle, false);
+			if (!vhandle)
+				break;
+
+			data->handles[j] = cpu_to_be32(vhandle);
+			j++;
+			break;
+		case TPM2_HT_HMAC_SESSION:
+		case TPM2_HT_POLICY_SESSION:
+			data->handles[j] = cpu_to_be32(phandle);
+			j++;
+			break;
+		default:
+			dev_err(&chip->dev, "%s: unknown handle 0x%08X\n",
+				__func__, phandle);
+			break;
+		}
+
+	}
+
+	header->length = cpu_to_be32(TPM_HEADER_SIZE + 9 + 4 * j);
+	data->count = cpu_to_be32(j);
+	return 0;
+}
+
+static int tpm2_save_space(struct tpm_chip *chip)
+{
+	struct tpm_space *space = &chip->work_space;
+	unsigned int offset;
+	int i;
+	int rc;
+
+	for (i = 0, offset = 0; i < ARRAY_SIZE(space->context_tbl); i++) {
+		if (!(space->context_tbl[i] && ~space->context_tbl[i]))
+			continue;
+
+		rc = tpm2_save_context(chip, space->context_tbl[i],
+				       space->context_buf, PAGE_SIZE,
+				       &offset);
+		if (rc == -ENOENT) {
+			space->context_tbl[i] = 0;
+			continue;
+		} else if (rc)
+			return rc;
+
+		space->context_tbl[i] = ~0;
+	}
+
+	return 0;
+}
+
+int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space,
+		      u32 cc, u8 *buf, size_t *bufsiz)
+{
+	struct tpm_output_header *header = (void *)buf;
+	int rc;
+
+	if (!space)
+		return 0;
+
+	rc = tpm2_map_response_header(chip, cc, buf, *bufsiz);
+	if (rc) {
+		tpm2_flush_space(chip);
+		return rc;
+	}
+
+	rc = tpm2_map_response_body(chip, cc, buf, *bufsiz);
+	if (rc) {
+		tpm2_flush_space(chip);
+		return rc;
+	}
+
+	rc = tpm2_save_space(chip);
+	if (rc) {
+		tpm2_flush_space(chip);
+		return rc;
+	}
+
+	*bufsiz = be32_to_cpu(header->length);
+
+	memcpy(&space->context_tbl, &chip->work_space.context_tbl,
+	       sizeof(space->context_tbl));
+	memcpy(space->context_buf, chip->work_space.context_buf, PAGE_SIZE);
+
+	return 0;
+}