tpm: move TPM 1.2 code of tpm_pcr_extend() to tpm1_pcr_extend()

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@huawei.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 7966d8d82d389f3ad2358dbcd0eea8acee3dfbf1..4ed08ab4d2a8860a2ce763757f9015fd94004534 100644 (file)
--- 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++) {