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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: Nayna Jain <nayna@linux.vnet.ibm.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Kenneth Goldman <kgold@linux.vnet.ibm.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
This commit is contained in:
Nayna Jain 2017-01-30 04:59:40 -05:00 committed by Jarkko Sakkinen
parent 7d761119a9
commit 1db15344f8
2 changed files with 82 additions and 0 deletions
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5
drivers/char/tpm/tpm.h
View File

@ -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

77
drivers/char/tpm/tpm2-cmd.c
View File

@ -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;
}