On Thu, Jan 26, 2017 at 07:23:15AM -0500, Stefan Berger wrote:
> 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;
> > +}
Can you submit a fixup that I could squash into existing patch? Thanks.
/Jarkko
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