On 01/20/2017 12:05 PM, 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>
> Reviewed-by: Jarkko Sakkinen <jarkko.sakki...@linux.intel.com>
> ---
> drivers/char/tpm/tpm.h | 5 ++++
> drivers/char/tpm/tpm2-cmd.c | 59
> +++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 64 insertions(+)
>
> diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
> index 1ae9768..c291f19 100644
> --- a/drivers/char/tpm/tpm.h
> +++ b/drivers/char/tpm/tpm.h
> @@ -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];
> @@ -545,4 +549,5 @@ 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..0e000a3 100644
> --- a/drivers/char/tpm/tpm2-cmd.c
> +++ b/drivers/char/tpm/tpm2-cmd.c
> @@ -998,3 +998,62 @@ 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;
> + 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;
> +
> + 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];
Now that we are checking access to the returned buffer, we should do an
additional check here:
end = &buf.data[TPM_HEADER_SIZE + rc];
> + for (i = 0; i < count; i++) {
if (marker + sizeof(pcr_selection) >= end) {
rc = -EFAULT;
goto out;
}
> + 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))
if (rc < 0 || count < ARRAY_SIZE(...))
I can send a separate patch for this. Let me know.
> + chip->active_banks[count] = TPM2_ALG_ERROR;
> +
> + tpm_buf_destroy(&buf);
> +
> + return rc;
> +}
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