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tpm: fix intermittent failure with self tests

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My Nuvoton 6xx in a Dell XPS-13 has been intermittently failing to work
(necessitating a reboot). The problem seems to be that the TPM gets into a
state where the partial self-test doesn't return TPM_RC_SUCCESS (meaning
all tests have run to completion), but instead returns TPM_RC_TESTING
(meaning some tests are still running in the background).  There are
various theories that resending the self-test command actually causes the
tests to restart and thus triggers more TPM_RC_TESTING returns until the
timeout is exceeded.

There are several issues here: firstly being we shouldn't slow down the
boot sequence waiting for the self test to complete once the TPM
backgrounds them.  It will actually make available all functions that have
passed and if it gets a failure return TPM_RC_FAILURE to every subsequent
command.  So the fix is to kick off self tests once and if they return
TPM_RC_TESTING log that as a backgrounded self test and continue on.  In
order to prevent other tpm users from seeing any TPM_RC_TESTING returns
(which it might if they send a command that needs a TPM subsystem which is
still under test), we loop in tpm_transmit_cmd until either a timeout or we
don't get a TPM_RC_TESTING return.

Finally, there have been observations of strange returns from a partial
test. One Nuvoton is occasionally returning TPM_RC_COMMAND_CODE, so treat
any unexpected return from a partial self test as an indication we need to
run a full self test.

[jarkko.sakkinen@linux.intel.com: cleaned up some klog messages and
 dropped tpm_transmit_check() helper function from James' original
 commit.]

Fixes: 2482b1bba5 ("tpm: Trigger only missing TPM 2.0 self tests")
Cc: stable@vger.kernel.org
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkine@linux.intel.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkine@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkine@linux.intel.com>
This commit is contained in:
James Bottomley 2018-03-22 17:32:20 +02:00 committed by Jarkko Sakkinen
parent e2fb992d82
commit 2be8ffed09
3 changed files with 31 additions and 40 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
drivers/char/tpm/tpm-interface.c
View File

@ -564,6 +564,8 @@ ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space,
ssize_t ret;
const size_t save_size = min(space ? sizeof(save) : TPM_HEADER_SIZE,
bufsiz);
/* the command code is where the return code will be */
u32 cc = be32_to_cpu(header->return_code);
/*
* Subtlety here: if we have a space, the handles will be
@ -577,11 +579,21 @@ ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space,
if (ret < 0)
break;
rc = be32_to_cpu(header->return_code);
if (rc != TPM2_RC_RETRY)
if (rc != TPM2_RC_RETRY && rc != TPM2_RC_TESTING)
break;
/*
* return immediately if self test returns test
* still running to shorten boot time.
*/
if (rc == TPM2_RC_TESTING && cc == TPM2_CC_SELF_TEST)
break;
delay_msec *= 2;
if (delay_msec > TPM2_DURATION_LONG) {
dev_err(&chip->dev, "TPM is in retry loop\n");
if (rc == TPM2_RC_RETRY)
dev_err(&chip->dev, "in retry loop\n");
else
dev_err(&chip->dev,
"self test is still running\n");
break;
}
tpm_msleep(delay_msec);

1
drivers/char/tpm/tpm.h
View File

@ -111,6 +111,7 @@ enum tpm2_return_codes {
TPM2_RC_HASH = 0x0083, /* RC_FMT1 */
TPM2_RC_HANDLE = 0x008B,
TPM2_RC_INITIALIZE = 0x0100, /* RC_VER1 */
TPM2_RC_FAILURE = 0x0101,
TPM2_RC_DISABLED = 0x0120,
TPM2_RC_COMMAND_CODE = 0x0143,
TPM2_RC_TESTING = 0x090A, /* RC_WARN */

54
drivers/char/tpm/tpm2-cmd.c
View File

@ -31,10 +31,6 @@ struct tpm2_startup_in {
__be16 startup_type;
} __packed;
struct tpm2_self_test_in {
u8 full_test;
} __packed;
struct tpm2_get_tpm_pt_in {
__be32 cap_id;
__be32 property_id;
@ -60,7 +56,6 @@ struct tpm2_get_random_out {
union tpm2_cmd_params {
struct tpm2_startup_in startup_in;
struct tpm2_self_test_in selftest_in;
struct tpm2_get_tpm_pt_in get_tpm_pt_in;
struct tpm2_get_tpm_pt_out get_tpm_pt_out;
struct tpm2_get_random_in getrandom_in;
@ -829,16 +824,6 @@ unsigned long tpm2_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal)
}
EXPORT_SYMBOL_GPL(tpm2_calc_ordinal_duration);
#define TPM2_SELF_TEST_IN_SIZE \
(sizeof(struct tpm_input_header) + \
sizeof(struct tpm2_self_test_in))
static const struct tpm_input_header tpm2_selftest_header = {
.tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
.length = cpu_to_be32(TPM2_SELF_TEST_IN_SIZE),
.ordinal = cpu_to_be32(TPM2_CC_SELF_TEST)
};
/**
* tpm2_do_selftest() - ensure that all self tests have passed
*
@ -854,27 +839,24 @@ static const struct tpm_input_header tpm2_selftest_header = {
*/
static int tpm2_do_selftest(struct tpm_chip *chip)
{
struct tpm_buf buf;
int full;
int rc;
unsigned int delay_msec = 10;
long duration;
struct tpm2_cmd cmd;
duration = jiffies_to_msecs(
tpm2_calc_ordinal_duration(chip, TPM2_CC_SELF_TEST));
for (full = 0; full < 2; full++) {
rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_SELF_TEST);
if (rc)
return rc;
while (1) {
cmd.header.in = tpm2_selftest_header;
cmd.params.selftest_in.full_test = 0;
tpm_buf_append_u8(&buf, full);
rc = tpm_transmit_cmd(chip, NULL, buf.data, PAGE_SIZE, 0, 0,
"attempting the self test");
tpm_buf_destroy(&buf);
rc = tpm_transmit_cmd(chip, NULL, &cmd, TPM2_SELF_TEST_IN_SIZE,
0, 0, "continue selftest");
if (rc != TPM2_RC_TESTING || delay_msec >= duration)
break;
/* wait longer than before */
delay_msec *= 2;
tpm_msleep(delay_msec);
if (rc == TPM2_RC_TESTING)
rc = TPM2_RC_SUCCESS;
if (rc == TPM2_RC_INITIALIZE || rc == TPM2_RC_SUCCESS)
return rc;
}
return rc;
@ -1060,10 +1042,8 @@ int tpm2_auto_startup(struct tpm_chip *chip)
goto out;
rc = tpm2_do_selftest(chip);
if (rc != 0 && rc != TPM2_RC_INITIALIZE) {
dev_err(&chip->dev, "TPM self test failed\n");
if (rc && rc != TPM2_RC_INITIALIZE)
goto out;
}
if (rc == TPM2_RC_INITIALIZE) {
rc = tpm_startup(chip);
@ -1071,10 +1051,8 @@ int tpm2_auto_startup(struct tpm_chip *chip)
goto out;
rc = tpm2_do_selftest(chip);
if (rc) {
dev_err(&chip->dev, "TPM self test failed\n");
if (rc)
goto out;
}
}
rc = tpm2_get_pcr_allocation(chip);