On 01/18/2017 07:15 PM, Jarkko Sakkinen wrote:
> On Wed, Jan 18, 2017 at 03:44:49AM -0500, Nayna Jain wrote:
>> 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 <na...@linux.vnet.ibm.com>
>> ---
>> drivers/char/tpm/tpm.h | 4 ++++
>> drivers/char/tpm/tpm2-cmd.c | 57
>> +++++++++++++++++++++++++++++++++++++++++++++
>> 2 files changed, 61 insertions(+)
>>
>> diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
>> index 1ae9768..dddd573 100644
>> --- a/drivers/char/tpm/tpm.h
>> +++ b/drivers/char/tpm/tpm.h
>> @@ -127,6 +127,7 @@ enum tpm2_permanent_handles {
>> };
>>
>> enum tpm2_capabilities {
>> + TPM2_CAP_PCRS = 5,
>> TPM2_CAP_TPM_PROPERTIES = 6,
>> };
>>
>> @@ -187,6 +188,8 @@ 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];
>> @@ -545,4 +548,5 @@ 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
>> diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
>> index 6eda239..75a7546 100644
>> --- a/drivers/char/tpm/tpm2-cmd.c
>> +++ b/drivers/char/tpm/tpm2-cmd.c
>> @@ -998,3 +998,60 @@ 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;
>> + unsigned int count = 0;
>
> You shouldn't initialize 'count'.
It is initialized for reason below:
>
>> + int rc;
>> + int i;
>> +
>> + 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, 0,
>> + "get tpm pcr allocation");
>> + if (rc < 0)
>> + goto out;
if tpm_transmit_cmd()fails, it jumps to out:
where count is used in if(..).
Thanks & Regards,
- Nayna
>> +
>> + count = be32_to_cpup(
>> + (__be32 *)&buf.data[TPM_HEADER_SIZE + 5]);
>> +
>> + if (count > ARRAY_SIZE(chip->active_banks))
>> + return -ENODEV;
>> +
>> + marker = &buf.data[TPM_HEADER_SIZE + 9];
>> + for (i = 0; i < count; i++) {
>> + memcpy(&pcr_selection, marker, sizeof(pcr_selection));
>> + chip->active_banks[i] = be16_to_cpu(pcr_selection.hash_alg);
>> + marker = marker + sizeof(struct tpm2_pcr_selection);
>> + }
>> +
>> +out:
>> + if (count < ARRAY_SIZE(chip->active_banks))
>> + chip->active_banks[count] = 0;
>> +
>> + tpm_buf_destroy(&buf);
>> +
>> + return rc;
>> +}
>> --
>> 2.5.0
>
> Otherwise,
>
> Reviewed-by: Jarkko Sakkinen <jarkko.sakk...@linux.intel.com>
>
> /Jarkko
>
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