From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: Nayna <nayna@linux.vnet.ibm.com>
Cc: tpmdd-devel@lists.sourceforge.net, peterhuewe@gmx.de,
tpmdd@selhorst.net, jgunthorpe@obsidianresearch.com,
linux-security-module@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 1/2] tpm: implement TPM 2.0 capability to get active PCR banks
Date: Thu, 19 Jan 2017 12:47:59 +0200 [thread overview]
Message-ID: <20170119104759.oqobziiuy7lqnzbf@intel.com> (raw)
In-Reply-To: <587F7252.4070808@linux.vnet.ibm.com>
On Wed, Jan 18, 2017 at 07:19:06PM +0530, Nayna wrote:
>
>
> 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 <nayna@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(..).
Why the out label is placed there and not after?
>
> Thanks & Regards,
> - Nayna
>
> > > +
> > > + count = be32_to_cpup(
> > > + (__be32 *)&buf.data[TPM_HEADER_SIZE + 5]);
> > > +
> > > + if (count > ARRAY_SIZE(chip->active_banks))
> > > + return -ENODEV;
Hey, here's a regression (didn't notice it last time). You
nee to call tpm_buf_destroy().
> > > +
> > > + 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.sakkien@linux.intel.com>
> >
> > /Jarkko
> >
>
/Jarkko
next prev parent reply other threads:[~2017-01-19 10:48 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-18 8:44 [PATCH v4 0/2] enhance TPM 2.0 extend function to support multiple PCR banks Nayna Jain
2017-01-18 8:44 ` [PATCH v4 1/2] tpm: implement TPM 2.0 capability to get active " Nayna Jain
2017-01-18 13:45 ` Jarkko Sakkinen
2017-01-18 13:49 ` Nayna
2017-01-19 10:47 ` Jarkko Sakkinen [this message]
2017-01-19 13:34 ` Nayna
2017-01-18 8:44 ` [PATCH v4 2/2] tpm: enhance TPM 2.0 PCR extend to support multiple banks Nayna Jain
2017-01-18 13:58 ` Jarkko Sakkinen
2017-01-19 9:18 ` Nayna
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