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Commit 1db15344 authored by Nayna Jain's avatar Nayna Jain Committed by Jarkko Sakkinen
Browse files

tpm: implement TPM 2.0 capability to get active PCR banks 



This patch implements the TPM 2.0 capability TPM_CAP_PCRS to
retrieve the active PCR banks from the TPM. This is needed
to enable extending all active banks as recommended by TPM 2.0
TCG Specification.

Signed-off-by: default avatarNayna Jain <nayna@linux.vnet.ibm.com>
Reviewed-by: default avatarJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: default avatarJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: default avatarKenneth Goldman <kgold@linux.vnet.ibm.com>
Signed-off-by: default avatarJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
parent 7d761119

drivers/char/tpm/tpm.h

+5 −0
Original line number Diff line number Diff line
@@ -97,6 +97,7 @@ enum tpm2_return_codes { 
};



enum tpm2_algorithms {

	TPM2_ALG_ERROR		= 0x0000,

	TPM2_ALG_SHA1		= 0x0004,

	TPM2_ALG_KEYEDHASH	= 0x0008,

	TPM2_ALG_SHA256		= 0x000B,
@@ -127,6 +128,7 @@ enum tpm2_permanent_handles { 
};



enum tpm2_capabilities {

	TPM2_CAP_PCRS		= 5,

	TPM2_CAP_TPM_PROPERTIES = 6,

};
@@ -187,6 +189,8 @@ struct tpm_chip { 


	const struct attribute_group *groups[3];

	unsigned int groups_cnt;



	u16 active_banks[7];

#ifdef CONFIG_ACPI

	acpi_handle acpi_dev_handle;

	char ppi_version[TPM_PPI_VERSION_LEN + 1];
@@ -540,4 +544,5 @@ int tpm2_auto_startup(struct tpm_chip *chip); 
void tpm2_shutdown(struct tpm_chip *chip, u16 shutdown_type);

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);

#endif

drivers/char/tpm/tpm2-cmd.c

+77 −0
Original line number Diff line number Diff line
@@ -1030,3 +1030,80 @@ int tpm2_auto_startup(struct tpm_chip *chip) 
		rc = -ENODEV;

	return rc;

}



struct tpm2_pcr_selection {

	__be16  hash_alg;

	u8  size_of_select;

	u8  pcr_select[3];

} __packed;



/**

 * tpm2_get_pcr_allocation() - get TPM active PCR banks.

 *

 * @chip: TPM chip to use.

 *

 * Return: Same as with tpm_transmit_cmd.

 */

ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip)

{

	struct tpm2_pcr_selection pcr_selection;

	struct tpm_buf buf;

	void *marker;

	void *end;

	void *pcr_select_offset;

	unsigned int count;

	u32 sizeof_pcr_selection;

	u32 rsp_len;

	int rc;

	int i = 0;



	rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_GET_CAPABILITY);

	if (rc)

		return rc;



	tpm_buf_append_u32(&buf, TPM2_CAP_PCRS);

	tpm_buf_append_u32(&buf, 0);

	tpm_buf_append_u32(&buf, 1);



	rc = tpm_transmit_cmd(chip, buf.data, PAGE_SIZE, 9, 0,

			      "get tpm pcr allocation");

	if (rc)

		goto out;



	count = be32_to_cpup(

		(__be32 *)&buf.data[TPM_HEADER_SIZE + 5]);



	if (count > ARRAY_SIZE(chip->active_banks)) {

		rc = -ENODEV;

		goto out;

	}



	marker = &buf.data[TPM_HEADER_SIZE + 9];



	rsp_len = be32_to_cpup((__be32 *)&buf.data[2]);

	end = &buf.data[rsp_len];



	for (i = 0; i < count; i++) {

		pcr_select_offset = marker +

			offsetof(struct tpm2_pcr_selection, size_of_select);

		if (pcr_select_offset >= end) {

			rc = -EFAULT;

			break;

		}



		memcpy(&pcr_selection, marker, sizeof(pcr_selection));

		chip->active_banks[i] = be16_to_cpu(pcr_selection.hash_alg);

		sizeof_pcr_selection = sizeof(pcr_selection.hash_alg) +

			sizeof(pcr_selection.size_of_select) +

			pcr_selection.size_of_select;

		marker = marker + sizeof_pcr_selection;

	}



out:

	if (i < ARRAY_SIZE(chip->active_banks))

		chip->active_banks[i] = TPM2_ALG_ERROR;



	tpm_buf_destroy(&buf);



	return rc;

}