| Message ID | 20180507153941.4952-1-nayna@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, May 07, 2018 at 09:09:41PM +0530, Nayna Jain wrote: > As per the TCG Specification[1][2], RC_COMMAND_CODE indicates that the TPM > command is not implemented or not supported. When RC_COMMAND_CODE is > returned in response to the partial selftest, this is not the case. TPM 2.0 > supports TPM2_GetTestResult[3], which can be used to check the selftest > status before sending the full selftest command. > > This patch implements the tpm2_get_selftest_result function to check the > selftest status when partial selftest returns RC_COMMAND_CODE. Cosmetic: parentheses when referring to functions. > This change results in finishing of the selftest much earlier compared to > the existing case where full selftest is immediately sent to retry. The > Pi's dmesg shows: the TPM selftest completed at 1.243864 secs compared > with the previous timestamp of 1.939667 secs. > > [1] As per the TCG Specification, Trusted Platform Module Library, > Part 2 - Structures, Section 6.6.3 and Section 4.18: > > "RC_COMMAND_CODE indicates the response code that is returned if the TPM is > unmarshalling a value that it expects to be a TPM_CC and the input value is > not in the table." > > [2] As per the TCG Specification, Trusted Platform Module Library, > Part 2 - Commands, Section 5.2: > > "The TPM shall successfully unmarshal a TPM_CC and verify that the command > is implemented (TPM_RC_COMMAND_CODE)." > > [3] As per the TCG Specification, Trusted Platform Module Library, > Part 2 - Commands, Section 10.4: > > "This command(TPM2_GetTestResult) returns manufacturer-specific information > regarding the results of a self-test and an indication of the test status." > > Signed-off-by: Nayna Jain <nayna@linux.vnet.ibm.com> > Tested-by: Mimi Zohar <zohar@linux.vnet.ibm.com> (on Pi with TPM 2.0) > --- > > Changelog v2: > * changed the subject and updated patch description > * removed the logs > > drivers/char/tpm/tpm.h | 2 ++ > drivers/char/tpm/tpm2-cmd.c | 48 +++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 50 insertions(+) > > diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h > index af3bb87d3ea1..1de4240b52c4 100644 > --- a/drivers/char/tpm/tpm.h > +++ b/drivers/char/tpm/tpm.h > @@ -114,6 +114,7 @@ enum tpm2_return_codes { > TPM2_RC_FAILURE = 0x0101, > TPM2_RC_DISABLED = 0x0120, > TPM2_RC_COMMAND_CODE = 0x0143, > + TPM2_RC_NEEDS_TEST = 0x0153, > TPM2_RC_TESTING = 0x090A, /* RC_WARN */ > TPM2_RC_REFERENCE_H0 = 0x0910, > TPM2_RC_RETRY = 0x0922, > @@ -144,6 +145,7 @@ enum tpm2_command_codes { > TPM2_CC_FLUSH_CONTEXT = 0x0165, > TPM2_CC_GET_CAPABILITY = 0x017A, > TPM2_CC_GET_RANDOM = 0x017B, > + TPM2_CC_GET_TEST_RESULT = 0x017C, > TPM2_CC_PCR_READ = 0x017E, > TPM2_CC_PCR_EXTEND = 0x0182, > TPM2_CC_LAST = 0x018F, > diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c > index 96c77c8e7f40..4abba0ebe25b 100644 > --- a/drivers/char/tpm/tpm2-cmd.c > +++ b/drivers/char/tpm/tpm2-cmd.c > @@ -825,6 +825,50 @@ unsigned long tpm2_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal) > EXPORT_SYMBOL_GPL(tpm2_calc_ordinal_duration); > > /** > + * tpm2_get_selftest_result() - get the status of self tests > + * There should not be an empty line here. > + * @chip: TPM chip to use > + * > + * Return: If error return rc, else return the result of the self tests. > + * TPM_RC_NEEDS_TESTING: No self tests are done. Needs testing. > + * TPM_RC_TESTING: Self tests are in progress. > + * TPM_RC_SUCCESS: Self tests completed successfully. > + * TPM_RC_FAILURE: Self tests completed failure. > + * > + * This function can be used to check the status of self tests on the TPM. > + */ Description should Better to just have: Return: TPM return code, -errno otherwise There is a lot of variance in return values but this is the format where I would like the code base to dilate to. Describing TPM return codes one by one is not very maintainable in the long run. See: https://www.kernel.org/doc/Documentation/kernel-doc-nano-HOWTO.txt > +static int tpm2_get_selftest_result(struct tpm_chip *chip) > +{ > + struct tpm_buf buf; > + int rc; > + int test_result; > + uint16_t data_size; > + int len; > + const struct tpm_output_header *header; > + > + rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_GET_TEST_RESULT); > + if (rc) > + return rc; > + > + len = tpm_transmit(chip, NULL, buf.data, PAGE_SIZE, 0); > + if (len < 0) > + return len; > + > + header = (struct tpm_output_header *)buf.data; > + > + rc = be32_to_cpu(header->return_code); > + if (rc) > + return rc; > + > + data_size = be16_to_cpup((__be16 *)&buf.data[TPM_HEADER_SIZE]); > + > + test_result = be32_to_cpup((__be32 *) > + (&buf.data[TPM_HEADER_SIZE + 2 + data_size])); > + > + return test_result; > +} > + > +/** > * tpm2_do_selftest() - ensure that all self tests have passed > * > * @chip: TPM chip to use > @@ -853,6 +897,10 @@ static int tpm2_do_selftest(struct tpm_chip *chip) > "attempting the self test"); > tpm_buf_destroy(&buf); > > + /* Check the selftest status */ What is the purpose of this comment eg what does it describe that isn't obvious? > + if (rc == TPM2_RC_COMMAND_CODE) > + rc = tpm2_get_selftest_result(chip); > + > if (rc == TPM2_RC_TESTING) > rc = TPM2_RC_SUCCESS; > if (rc == TPM2_RC_INITIALIZE || rc == TPM2_RC_SUCCESS) > -- > 2.13.6 > -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h index af3bb87d3ea1..1de4240b52c4 100644 --- a/drivers/char/tpm/tpm.h +++ b/drivers/char/tpm/tpm.h @@ -114,6 +114,7 @@ enum tpm2_return_codes { TPM2_RC_FAILURE = 0x0101, TPM2_RC_DISABLED = 0x0120, TPM2_RC_COMMAND_CODE = 0x0143, + TPM2_RC_NEEDS_TEST = 0x0153, TPM2_RC_TESTING = 0x090A, /* RC_WARN */ TPM2_RC_REFERENCE_H0 = 0x0910, TPM2_RC_RETRY = 0x0922, @@ -144,6 +145,7 @@ enum tpm2_command_codes { TPM2_CC_FLUSH_CONTEXT = 0x0165, TPM2_CC_GET_CAPABILITY = 0x017A, TPM2_CC_GET_RANDOM = 0x017B, + TPM2_CC_GET_TEST_RESULT = 0x017C, TPM2_CC_PCR_READ = 0x017E, TPM2_CC_PCR_EXTEND = 0x0182, TPM2_CC_LAST = 0x018F, diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c index 96c77c8e7f40..4abba0ebe25b 100644 --- a/drivers/char/tpm/tpm2-cmd.c +++ b/drivers/char/tpm/tpm2-cmd.c @@ -825,6 +825,50 @@ unsigned long tpm2_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal) EXPORT_SYMBOL_GPL(tpm2_calc_ordinal_duration); /** + * tpm2_get_selftest_result() - get the status of self tests + * + * @chip: TPM chip to use + * + * Return: If error return rc, else return the result of the self tests. + * TPM_RC_NEEDS_TESTING: No self tests are done. Needs testing. + * TPM_RC_TESTING: Self tests are in progress. + * TPM_RC_SUCCESS: Self tests completed successfully. + * TPM_RC_FAILURE: Self tests completed failure. + * + * This function can be used to check the status of self tests on the TPM. + */ +static int tpm2_get_selftest_result(struct tpm_chip *chip) +{ + struct tpm_buf buf; + int rc; + int test_result; + uint16_t data_size; + int len; + const struct tpm_output_header *header; + + rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_GET_TEST_RESULT); + if (rc) + return rc; + + len = tpm_transmit(chip, NULL, buf.data, PAGE_SIZE, 0); + if (len < 0) + return len; + + header = (struct tpm_output_header *)buf.data; + + rc = be32_to_cpu(header->return_code); + if (rc) + return rc; + + data_size = be16_to_cpup((__be16 *)&buf.data[TPM_HEADER_SIZE]); + + test_result = be32_to_cpup((__be32 *) + (&buf.data[TPM_HEADER_SIZE + 2 + data_size])); + + return test_result; +} + +/** * tpm2_do_selftest() - ensure that all self tests have passed * * @chip: TPM chip to use @@ -853,6 +897,10 @@ static int tpm2_do_selftest(struct tpm_chip *chip) "attempting the self test"); tpm_buf_destroy(&buf); + /* Check the selftest status */ + if (rc == TPM2_RC_COMMAND_CODE) + rc = tpm2_get_selftest_result(chip); + if (rc == TPM2_RC_TESTING) rc = TPM2_RC_SUCCESS; if (rc == TPM2_RC_INITIALIZE || rc == TPM2_RC_SUCCESS)