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TPM: chip disabled state erronously being reported as error

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tpm_do_selftest() attempts to read a PCR in order to
decide if one can rely on the TPM being used or not.
The function that's used by __tpm_pcr_read() does not
expect the TPM to be disabled or deactivated, and if so,
reports an error.

It's fine if the TPM returns this error when trying to
use it for the first time after a power cycle, but it's
definitely not if it already returned success for a
previous attempt to read one of its PCRs.

The tpm_do_selftest() was modified so that the driver only
reports this return code as an error when it really is.

Reported-and-tested-by: Paul Bolle <pebolle@tiscali.nl>
Cc: Stable <stable@vger.kernel.org>
Signed-off-by: Rajiv Andrade <srajiv@linux.vnet.ibm.com>
This commit is contained in:
Rajiv Andrade 2012-04-24 17:38:17 -03:00
parent cbb2d5e459
commit 24ebe6670d
1 changed files with 10 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
drivers/char/tpm/tpm.c
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@ -827,10 +827,10 @@ EXPORT_SYMBOL_GPL(tpm_pcr_extend);
int tpm_do_selftest(struct tpm_chip *chip)
{
int rc;
u8 digest[TPM_DIGEST_SIZE];
unsigned int loops;
unsigned int delay_msec = 1000;
unsigned long duration;
struct tpm_cmd_t cmd;
duration = tpm_calc_ordinal_duration(chip,
TPM_ORD_CONTINUE_SELFTEST);
@ -845,7 +845,15 @@ int tpm_do_selftest(struct tpm_chip *chip)
return rc;
do {
rc = __tpm_pcr_read(chip, 0, digest);
/* 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);
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);