2016-03-30 13:20:53

by Jarkko Sakkinen

[permalink] [raw]
Subject: [PATCH] tpm: remove redundant code from self-test functions

Self-test functions construct PCR read calls by ad hoc, which is only a
waste space. Use instead tpm_pcr_read_dev (renamed as tpm1_pcr_read() by
this commit) in tpm_do_selftest and tpm2_pcr_read() in
tpm2_do_selftest() functions in order to remove the duplicate code.

Patch can be tested easily tested by running the a kernel with this
patch compiled in since self-test is done when the a device driver
initializes.

Signed-off-by: Jarkko Sakkinen <[email protected]>
---
drivers/char/tpm/tpm-interface.c | 14 +++++---------
drivers/char/tpm/tpm-sysfs.c | 2 +-
drivers/char/tpm/tpm.h | 2 +-
drivers/char/tpm/tpm2-cmd.c | 14 ++------------
4 files changed, 9 insertions(+), 23 deletions(-)

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 5397b64..0c8140f 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -1,6 +1,6 @@
/*
* Copyright (C) 2004 IBM Corporation
- * Copyright (C) 2014 Intel Corporation
+ * Copyright (C) 2014, 2016 Intel Corporation
*
* Authors:
* Leendert van Doorn <[email protected]>
@@ -666,7 +666,7 @@ static struct tpm_input_header pcrread_header = {
.ordinal = TPM_ORDINAL_PCRREAD
};

-int tpm_pcr_read_dev(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
+int tpm1_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
{
int rc;
struct tpm_cmd_t cmd;
@@ -676,7 +676,7 @@ int tpm_pcr_read_dev(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
rc = tpm_transmit_cmd(chip, &cmd, READ_PCR_RESULT_SIZE,
"attempting to read a pcr value");

- if (rc == 0)
+ if (rc == 0 && res_buf)
memcpy(res_buf, cmd.params.pcrread_out.pcr_result,
TPM_DIGEST_SIZE);
return rc;
@@ -728,7 +728,7 @@ int tpm_pcr_read(u32 chip_num, int pcr_idx, u8 *res_buf)
if (chip->flags & TPM_CHIP_FLAG_TPM2)
rc = tpm2_pcr_read(chip, pcr_idx, res_buf);
else
- rc = tpm_pcr_read_dev(chip, pcr_idx, res_buf);
+ rc = tpm1_pcr_read(chip, pcr_idx, res_buf);
tpm_put_ops(chip);
return rc;
}
@@ -793,7 +793,6 @@ int tpm_do_selftest(struct tpm_chip *chip)
unsigned int loops;
unsigned int delay_msec = 100;
unsigned long duration;
- struct tpm_cmd_t cmd;

duration = tpm_calc_ordinal_duration(chip, TPM_ORD_CONTINUE_SELFTEST);

@@ -808,9 +807,7 @@ int tpm_do_selftest(struct tpm_chip *chip)

do {
/* Attempt to read a PCR value */
- cmd.header.in = pcrread_header;
- cmd.params.pcrread_in.pcr_idx = cpu_to_be32(0);
- rc = tpm_transmit(chip, (u8 *) &cmd, READ_PCR_RESULT_SIZE);
+ rc = tpm1_pcr_read(chip, 0, NULL);
/* Some buggy TPMs will not respond to tpm_tis_ready() for
* around 300ms while the self test is ongoing, keep trying
* until the self test duration expires. */
@@ -825,7 +822,6 @@ int tpm_do_selftest(struct tpm_chip *chip)
if (rc < TPM_HEADER_SIZE)
return -EFAULT;

- rc = be32_to_cpu(cmd.header.out.return_code);
if (rc == TPM_ERR_DISABLED || rc == TPM_ERR_DEACTIVATED) {
dev_info(&chip->dev,
"TPM is disabled/deactivated (0x%X)\n", rc);
diff --git a/drivers/char/tpm/tpm-sysfs.c b/drivers/char/tpm/tpm-sysfs.c
index 34e7fc7..48e30bd 100644
--- a/drivers/char/tpm/tpm-sysfs.c
+++ b/drivers/char/tpm/tpm-sysfs.c
@@ -101,7 +101,7 @@ static ssize_t pcrs_show(struct device *dev, struct device_attribute *attr,

num_pcrs = be32_to_cpu(cap.num_pcrs);
for (i = 0; i < num_pcrs; i++) {
- rc = tpm_pcr_read_dev(chip, i, digest);
+ rc = tpm1_pcr_read(chip, i, digest);
if (rc)
break;
str += sprintf(str, "PCR-%02d: ", i);
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index cd780c7..89740db 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -511,7 +511,7 @@ extern void tpm_chip_unregister(struct tpm_chip *chip);
int tpm_sysfs_add_device(struct tpm_chip *chip);
void tpm_sysfs_del_device(struct tpm_chip *chip);

-int tpm_pcr_read_dev(struct tpm_chip *chip, int pcr_idx, u8 *res_buf);
+int tpm1_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf);

#ifdef CONFIG_ACPI
extern void tpm_add_ppi(struct tpm_chip *chip);
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 5fc0e7c..afe8d47 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -284,7 +284,7 @@ int tpm2_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)

rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd),
"attempting to read a pcr value");
- if (rc == 0) {
+ if (rc == 0 && res_buf) {
buf = cmd.params.pcrread_out.digest;
memcpy(res_buf, buf, TPM_DIGEST_SIZE);
}
@@ -861,7 +861,6 @@ int tpm2_do_selftest(struct tpm_chip *chip)
unsigned int loops;
unsigned int delay_msec = 100;
unsigned long duration;
- struct tpm2_cmd cmd;
int i;

duration = tpm2_calc_ordinal_duration(chip, TPM2_CC_SELF_TEST);
@@ -874,19 +873,10 @@ int tpm2_do_selftest(struct tpm_chip *chip)

for (i = 0; i < loops; i++) {
/* Attempt to read a PCR value */
- cmd.header.in = tpm2_pcrread_header;
- cmd.params.pcrread_in.pcr_selects_cnt = cpu_to_be32(1);
- cmd.params.pcrread_in.hash_alg = cpu_to_be16(TPM2_ALG_SHA1);
- cmd.params.pcrread_in.pcr_select_size = TPM2_PCR_SELECT_MIN;
- cmd.params.pcrread_in.pcr_select[0] = 0x01;
- cmd.params.pcrread_in.pcr_select[1] = 0x00;
- cmd.params.pcrread_in.pcr_select[2] = 0x00;
-
- rc = tpm_transmit_cmd(chip, (u8 *) &cmd, sizeof(cmd), NULL);
+ rc = tpm2_pcr_read(chip, 0, NULL);
if (rc < 0)
break;

- rc = be32_to_cpu(cmd.header.out.return_code);
if (rc != TPM2_RC_TESTING)
break;

--
1.9.1


2016-03-30 13:25:46

by Jarkko Sakkinen

[permalink] [raw]
Subject: Re: [PATCH] tpm: remove redundant code from self-test functions

On Wed, Mar 30, 2016 at 04:20:45PM +0300, Jarkko Sakkinen wrote:
> Self-test functions construct PCR read calls by ad hoc, which is only a
> waste space. Use instead tpm_pcr_read_dev (renamed as tpm1_pcr_read() by
> this commit) in tpm_do_selftest and tpm2_pcr_read() in
> tpm2_do_selftest() functions in order to remove the duplicate code.
>
> Patch can be tested easily tested by running the a kernel with this
> patch compiled in since self-test is done when the a device driver
> initializes.

This is now fixed version (I forgot to squash one fixup to the previous
version). This could use peer test preferably with a FIFO device. It is
easy as one only needs to load the driver and see that there are no
errors in dmesg from self-additions. As an additional measure on a TPM
1.x device outputting 'pcrs' file could be a good idea.

/Jarkko

> Signed-off-by: Jarkko Sakkinen <[email protected]>
> ---
> drivers/char/tpm/tpm-interface.c | 14 +++++---------
> drivers/char/tpm/tpm-sysfs.c | 2 +-
> drivers/char/tpm/tpm.h | 2 +-
> drivers/char/tpm/tpm2-cmd.c | 14 ++------------
> 4 files changed, 9 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> index 5397b64..0c8140f 100644
> --- a/drivers/char/tpm/tpm-interface.c
> +++ b/drivers/char/tpm/tpm-interface.c
> @@ -1,6 +1,6 @@
> /*
> * Copyright (C) 2004 IBM Corporation
> - * Copyright (C) 2014 Intel Corporation
> + * Copyright (C) 2014, 2016 Intel Corporation
> *
> * Authors:
> * Leendert van Doorn <[email protected]>
> @@ -666,7 +666,7 @@ static struct tpm_input_header pcrread_header = {
> .ordinal = TPM_ORDINAL_PCRREAD
> };
>
> -int tpm_pcr_read_dev(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
> +int tpm1_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
> {
> int rc;
> struct tpm_cmd_t cmd;
> @@ -676,7 +676,7 @@ int tpm_pcr_read_dev(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
> rc = tpm_transmit_cmd(chip, &cmd, READ_PCR_RESULT_SIZE,
> "attempting to read a pcr value");
>
> - if (rc == 0)
> + if (rc == 0 && res_buf)
> memcpy(res_buf, cmd.params.pcrread_out.pcr_result,
> TPM_DIGEST_SIZE);
> return rc;
> @@ -728,7 +728,7 @@ int tpm_pcr_read(u32 chip_num, int pcr_idx, u8 *res_buf)
> if (chip->flags & TPM_CHIP_FLAG_TPM2)
> rc = tpm2_pcr_read(chip, pcr_idx, res_buf);
> else
> - rc = tpm_pcr_read_dev(chip, pcr_idx, res_buf);
> + rc = tpm1_pcr_read(chip, pcr_idx, res_buf);
> tpm_put_ops(chip);
> return rc;
> }
> @@ -793,7 +793,6 @@ int tpm_do_selftest(struct tpm_chip *chip)
> unsigned int loops;
> unsigned int delay_msec = 100;
> unsigned long duration;
> - struct tpm_cmd_t cmd;
>
> duration = tpm_calc_ordinal_duration(chip, TPM_ORD_CONTINUE_SELFTEST);
>
> @@ -808,9 +807,7 @@ int tpm_do_selftest(struct tpm_chip *chip)
>
> do {
> /* Attempt to read a PCR value */
> - cmd.header.in = pcrread_header;
> - cmd.params.pcrread_in.pcr_idx = cpu_to_be32(0);
> - rc = tpm_transmit(chip, (u8 *) &cmd, READ_PCR_RESULT_SIZE);
> + rc = tpm1_pcr_read(chip, 0, NULL);
> /* Some buggy TPMs will not respond to tpm_tis_ready() for
> * around 300ms while the self test is ongoing, keep trying
> * until the self test duration expires. */
> @@ -825,7 +822,6 @@ int tpm_do_selftest(struct tpm_chip *chip)
> if (rc < TPM_HEADER_SIZE)
> return -EFAULT;
>
> - rc = be32_to_cpu(cmd.header.out.return_code);
> if (rc == TPM_ERR_DISABLED || rc == TPM_ERR_DEACTIVATED) {
> dev_info(&chip->dev,
> "TPM is disabled/deactivated (0x%X)\n", rc);
> diff --git a/drivers/char/tpm/tpm-sysfs.c b/drivers/char/tpm/tpm-sysfs.c
> index 34e7fc7..48e30bd 100644
> --- a/drivers/char/tpm/tpm-sysfs.c
> +++ b/drivers/char/tpm/tpm-sysfs.c
> @@ -101,7 +101,7 @@ static ssize_t pcrs_show(struct device *dev, struct device_attribute *attr,
>
> num_pcrs = be32_to_cpu(cap.num_pcrs);
> for (i = 0; i < num_pcrs; i++) {
> - rc = tpm_pcr_read_dev(chip, i, digest);
> + rc = tpm1_pcr_read(chip, i, digest);
> if (rc)
> break;
> str += sprintf(str, "PCR-%02d: ", i);
> diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
> index cd780c7..89740db 100644
> --- a/drivers/char/tpm/tpm.h
> +++ b/drivers/char/tpm/tpm.h
> @@ -511,7 +511,7 @@ extern void tpm_chip_unregister(struct tpm_chip *chip);
> int tpm_sysfs_add_device(struct tpm_chip *chip);
> void tpm_sysfs_del_device(struct tpm_chip *chip);
>
> -int tpm_pcr_read_dev(struct tpm_chip *chip, int pcr_idx, u8 *res_buf);
> +int tpm1_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf);
>
> #ifdef CONFIG_ACPI
> extern void tpm_add_ppi(struct tpm_chip *chip);
> diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
> index 5fc0e7c..afe8d47 100644
> --- a/drivers/char/tpm/tpm2-cmd.c
> +++ b/drivers/char/tpm/tpm2-cmd.c
> @@ -284,7 +284,7 @@ int tpm2_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
>
> rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd),
> "attempting to read a pcr value");
> - if (rc == 0) {
> + if (rc == 0 && res_buf) {
> buf = cmd.params.pcrread_out.digest;
> memcpy(res_buf, buf, TPM_DIGEST_SIZE);
> }
> @@ -861,7 +861,6 @@ int tpm2_do_selftest(struct tpm_chip *chip)
> unsigned int loops;
> unsigned int delay_msec = 100;
> unsigned long duration;
> - struct tpm2_cmd cmd;
> int i;
>
> duration = tpm2_calc_ordinal_duration(chip, TPM2_CC_SELF_TEST);
> @@ -874,19 +873,10 @@ int tpm2_do_selftest(struct tpm_chip *chip)
>
> for (i = 0; i < loops; i++) {
> /* Attempt to read a PCR value */
> - cmd.header.in = tpm2_pcrread_header;
> - cmd.params.pcrread_in.pcr_selects_cnt = cpu_to_be32(1);
> - cmd.params.pcrread_in.hash_alg = cpu_to_be16(TPM2_ALG_SHA1);
> - cmd.params.pcrread_in.pcr_select_size = TPM2_PCR_SELECT_MIN;
> - cmd.params.pcrread_in.pcr_select[0] = 0x01;
> - cmd.params.pcrread_in.pcr_select[1] = 0x00;
> - cmd.params.pcrread_in.pcr_select[2] = 0x00;
> -
> - rc = tpm_transmit_cmd(chip, (u8 *) &cmd, sizeof(cmd), NULL);
> + rc = tpm2_pcr_read(chip, 0, NULL);
> if (rc < 0)
> break;
>
> - rc = be32_to_cpu(cmd.header.out.return_code);
> if (rc != TPM2_RC_TESTING)
> break;
>
> --
> 1.9.1
>

2016-03-31 05:46:35

by Jason Gunthorpe

[permalink] [raw]
Subject: Re: [PATCH] tpm: remove redundant code from self-test functions

On Wed, Mar 30, 2016 at 04:20:45PM +0300, Jarkko Sakkinen wrote:

> - rc = be32_to_cpu(cmd.header.out.return_code);
> if (rc == TPM_ERR_DISABLED || rc == TPM_ERR_DEACTIVATED) {

This line is the entire reason it is open coded, I see it being
removed, but I don't see how the functionality is maintained?

Jason

2016-03-31 06:38:00

by Jarkko Sakkinen

[permalink] [raw]
Subject: Re: [PATCH] tpm: remove redundant code from self-test functions

On Wed, Mar 30, 2016 at 11:46:23PM -0600, Jason Gunthorpe wrote:
> On Wed, Mar 30, 2016 at 04:20:45PM +0300, Jarkko Sakkinen wrote:
>
> > - rc = be32_to_cpu(cmd.header.out.return_code);
> > if (rc == TPM_ERR_DISABLED || rc == TPM_ERR_DEACTIVATED) {
>
> This line is the entire reason it is open coded, I see it being
> removed, but I don't see how the functionality is maintained?

When tpm_trance_cmd() returns a positive number it is the TPM error code
that it returns. tpm_pcr_read() does pass through whatever
tpm_trace_cmd() returns so the above condition should still work as
expected.

> Jason

/Jarkko

2016-04-02 03:16:26

by Jason Gunthorpe

[permalink] [raw]
Subject: Re: [PATCH] tpm: remove redundant code from self-test functions

On Thu, Mar 31, 2016 at 09:37:56AM +0300, Jarkko Sakkinen wrote:
> On Wed, Mar 30, 2016 at 11:46:23PM -0600, Jason Gunthorpe wrote:
> > On Wed, Mar 30, 2016 at 04:20:45PM +0300, Jarkko Sakkinen wrote:
> >
> > > - rc = be32_to_cpu(cmd.header.out.return_code);
> > > if (rc == TPM_ERR_DISABLED || rc == TPM_ERR_DEACTIVATED) {
> >
> > This line is the entire reason it is open coded, I see it being
> > removed, but I don't see how the functionality is maintained?
>
> When tpm_trance_cmd() returns a positive number it is the TPM error code
> that it returns. tpm_pcr_read() does pass through whatever
> tpm_trace_cmd() returns so the above condition should still work as
> expected.

Okay, everything looks fine to me

Jason

2016-04-05 09:42:26

by Jarkko Sakkinen

[permalink] [raw]
Subject: Re: [PATCH] tpm: remove redundant code from self-test functions

On Fri, Apr 01, 2016 at 09:16:15PM -0600, Jason Gunthorpe wrote:
> On Thu, Mar 31, 2016 at 09:37:56AM +0300, Jarkko Sakkinen wrote:
> > On Wed, Mar 30, 2016 at 11:46:23PM -0600, Jason Gunthorpe wrote:
> > > On Wed, Mar 30, 2016 at 04:20:45PM +0300, Jarkko Sakkinen wrote:
> > >
> > > > - rc = be32_to_cpu(cmd.header.out.return_code);
> > > > if (rc == TPM_ERR_DISABLED || rc == TPM_ERR_DEACTIVATED) {
> > >
> > > This line is the entire reason it is open coded, I see it being
> > > removed, but I don't see how the functionality is maintained?
> >
> > When tpm_trance_cmd() returns a positive number it is the TPM error code
> > that it returns. tpm_pcr_read() does pass through whatever
> > tpm_trace_cmd() returns so the above condition should still work as
> > expected.
>
> Okay, everything looks fine to me

I applied this to http://git.infradead.org/users/jjs/linux-tpmdd.git in
order to get exposure (tested-by's are always welcome).

> Jason

/Jarkko

2016-04-07 11:30:52

by Jarkko Sakkinen

[permalink] [raw]
Subject: Re: [PATCH] tpm: remove redundant code from self-test functions

On Wed, Apr 06, 2016 at 04:03:52PM +0200, Christophe Ricard wrote:
> Hi Jarkko,
>
> I think there is a bug in the current version of this patch.
> tpm1_pcr_read returns TPM status code (>= 0)
>
> In tpm_do_selftest, after tpm1_pcr_read, rc is compared with
> TPM_HEADER_SIZE.
>
> In short:
> "if (rc == TPM_ERR_DISABLED || rc == TPM_ERR_DEACTIVATED) {" is never
> reached because TPM_ERR_DISABLED(0x7) and TPM_ERR_DEACTIVATED(0x6) are <
> TPM_HEADER size.
> TPM_HEADER_SIZE beeing already checked in tpm_transmit_cmd, i think a
> reasonable fix will be to remove:
> if (rc < TPM_HEADER_SIZE)
>        return -EFAULT;
>
> in tpm_do_self_test.
>
> Can you merge this fix into the current patch or do you want me to send it
> to you ?

This is my bad and thanks for catching this. I tested the patch but for
some reason the patch that I sent to LKML does not have this check
removed. The check can be safely removed because the same check is done
internally by tpm_transmit().

For now I removed the patch from my master branch since there is a crash
that I'm debugging and this is low priority change. I'll include this
change among couple of other patches to a patches to a patch set that
unifies all parts to call tpm_transmit_cmd() later on.

Thanks again for spotting this!

/Jarkko

> Best Regards
> Christophe
> 2016-04-05 11:42 GMT+02:00 Jarkko Sakkinen
> <[email protected]>:
>
> On Fri, Apr 01, 2016 at 09:16:15PM -0600, Jason Gunthorpe wrote:
> > On Thu, Mar 31, 2016 at 09:37:56AM +0300, Jarkko Sakkinen wrote:
> > > On Wed, Mar 30, 2016 at 11:46:23PM -0600, Jason Gunthorpe wrote:
> > > > On Wed, Mar 30, 2016 at 04:20:45PM +0300, Jarkko Sakkinen wrote:
> > > >
> > > > > -               rc =
> be32_to_cpu(cmd.header.out.return_code);
> > > > >                 if (rc == TPM_ERR_DISABLED || rc ==
> TPM_ERR_DEACTIVATED) {
> > > >
> > > > This line is the entire reason it is open coded, I see it being
> > > > removed, but I don't see how the functionality is maintained?
> > >
> > > When tpm_trance_cmd() returns a positive number it is the TPM error
> code
> > > that it returns. tpm_pcr_read() does pass through whatever
> > > tpm_trace_cmd() returns so the above condition should still work as
> > > expected.
> >
> > Okay, everything looks fine to me
>
> I applied this to http://git.infradead.org/users/jjs/linux-tpmdd.git in
> order to get exposure (tested-by's are always welcome).
>
> > Jason
> /Jarkko