[PATCH v2, RESEND 3/3] tpm: move TPM 1.2 code of tpm_pcr_extend() to tpm1_pcr_extend()

From: Roberto Sassu
Date: Thu May 04 2017 - 07:19:28 EST


In preparation of the modifications to tpm_pcr_extend(), which will
allow callers to supply a digest for each PCR bank of a TPM 2.0,
the TPM 1.2 specific code has been moved to tpm1_pcr_extend().

tpm1_pcr_extend() uses tpm_buf_init() to prepare the command buffer,
which offers protection against buffer overflow. It is called by
tpm_pcr_extend() and tpm_pm_suspend().

Signed-off-by: Roberto Sassu <roberto.sassu@xxxxxxxxxx>
---
drivers/char/tpm/tpm-interface.c | 41 +++++++++++++++++++++++-----------------
1 file changed, 24 insertions(+), 17 deletions(-)

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 7966d8d..4ed08ab 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -847,6 +847,25 @@ static const struct tpm_input_header pcrextend_header = {
.ordinal = cpu_to_be32(TPM_ORD_PCR_EXTEND)
};

+static int tpm1_pcr_extend(struct tpm_chip *chip, int pcr_idx, const u8 *hash,
+ char *log_msg)
+{
+ struct tpm_buf buf;
+ int rc;
+
+ rc = tpm_buf_init(&buf, TPM_TAG_RQU_COMMAND, TPM_ORD_PCR_EXTEND);
+ if (rc)
+ return rc;
+
+ tpm_buf_append_u32(&buf, pcr_idx);
+ tpm_buf_append(&buf, hash, TPM_DIGEST_SIZE);
+
+ rc = tpm_transmit_cmd(chip, NULL, buf.data, EXTEND_PCR_RESULT_SIZE,
+ EXTEND_PCR_RESULT_BODY_SIZE, 0, log_msg);
+ tpm_buf_destroy(&buf);
+ return rc;
+}
+
/**
* tpm_pcr_extend - extend pcr value with hash
* @chip_num: tpm idx # or AN&
@@ -859,7 +878,6 @@ static const struct tpm_input_header pcrextend_header = {
*/
int tpm_pcr_extend(u32 chip_num, int pcr_idx, const u8 *hash)
{
- struct tpm_cmd_t cmd;
int rc;
struct tpm_chip *chip;
struct tpm2_digest digest_list[ARRAY_SIZE(chip->active_banks)];
@@ -885,13 +903,8 @@ int tpm_pcr_extend(u32 chip_num, int pcr_idx, const u8 *hash)
return rc;
}

- cmd.header.in = pcrextend_header;
- cmd.params.pcrextend_in.pcr_idx = cpu_to_be32(pcr_idx);
- memcpy(cmd.params.pcrextend_in.hash, hash, TPM_DIGEST_SIZE);
- rc = tpm_transmit_cmd(chip, NULL, &cmd, EXTEND_PCR_RESULT_SIZE,
- EXTEND_PCR_RESULT_BODY_SIZE, 0,
- "attempting extend a PCR value");
-
+ rc = tpm1_pcr_extend(chip, pcr_idx, hash,
+ "attempting extend a PCR value");
tpm_put_ops(chip);
return rc;
}
@@ -1090,15 +1103,9 @@ int tpm_pm_suspend(struct device *dev)
}

/* for buggy tpm, flush pcrs with extend to selected dummy */
- if (tpm_suspend_pcr) {
- cmd.header.in = pcrextend_header;
- cmd.params.pcrextend_in.pcr_idx = cpu_to_be32(tpm_suspend_pcr);
- memcpy(cmd.params.pcrextend_in.hash, dummy_hash,
- TPM_DIGEST_SIZE);
- rc = tpm_transmit_cmd(chip, NULL, &cmd, EXTEND_PCR_RESULT_SIZE,
- EXTEND_PCR_RESULT_BODY_SIZE, 0,
- "extending dummy pcr before suspend");
- }
+ if (tpm_suspend_pcr)
+ rc = tpm1_pcr_extend(chip, tpm_suspend_pcr, dummy_hash,
+ "extending dummy pcr before suspend");

/* now do the actual savestate */
for (try = 0; try < TPM_RETRY; try++) {
--
2.9.3