[PATCH v3 2/6] tpm: use tpm2_pcr_read_tpm_buf() in tpm2_do_selftest()

Roberto Sassu
2017-06-21T14:34:42Z

tpm2_do_selftest() performs a PCR read during the TPM initialization phase.
This patch replaces the PCR read code with a call to
tpm2_pcr_read_tpm_buf(). tpm2_do_selftest() parses the result of the
TPM command, in order to retrieve the return code.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
---
drivers/char/tpm/tpm2-cmd.c | 32 ++++++++++----------------------
1 file changed, 10 insertions(+), 22 deletions(-)

diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index afd1b63..6a9fe0d 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -227,16 +227,6 @@ static const u8 tpm2_ordinal_duration[TPM2_CC_LAST - TPM2_CC_FIRST + 1] = {
TPM_UNDEFINED /* 18f */
};

-#define TPM2_PCR_READ_IN_SIZE \
- (sizeof(struct tpm_input_header) + \
- sizeof(struct tpm2_pcr_read_in))
-
-static const struct tpm_input_header tpm2_pcrread_header = {
- .tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
- .length = cpu_to_be32(TPM2_PCR_READ_IN_SIZE),
- .ordinal = cpu_to_be32(TPM2_CC_PCR_READ)
-};
-
static int tpm2_pcr_read_tpm_buf(struct tpm_chip *chip, int pcr_idx,
enum tpm2_algorithms algo, struct tpm_buf *buf,
char *msg)
@@ -938,7 +928,8 @@ static int tpm2_do_selftest(struct tpm_chip *chip)
unsigned int loops;
unsigned int delay_msec = 100;
unsigned long duration;
- struct tpm2_cmd cmd;
+ struct tpm_buf buf;
+ tpm_cmd_header *header;
int i;

duration = tpm2_calc_ordinal_duration(chip, TPM2_CC_SELF_TEST);
@@ -951,20 +942,17 @@ static 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, NULL, &cmd, sizeof(cmd), 0, 0,
- NULL);
+ rc = tpm2_pcr_read_tpm_buf(chip, 0, TPM2_ALG_SHA1, &buf, NULL);
+ if (rc >= 0) {
+ header = (tpm_cmd_header *)buf.data;
+ rc = be32_to_cpu(header->out.return_code);
+ }
+
+ tpm_buf_destroy(&buf);
+
if (rc < 0)
break;

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

--
2.9.3