1 files changed, 46 insertions, 5 deletions

diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
index 5d6487575074..92aea758d9c6 100644
--- a/drivers/char/tpm/tpm2-space.c
+++ b/drivers/char/tpm/tpm2-space.c
@@ -264,14 +264,54 @@ static int tpm2_map_command(struct tpm_chip *chip, u32 cc, u8 *cmd)
 	return 0;
 }
 
-int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u32 cc,
-		       u8 *cmd)
+static int tpm_find_and_validate_cc(struct tpm_chip *chip,
+				    struct tpm_space *space,
+				    const void *cmd, size_t len)
+{
+	const struct tpm_header *header = (const void *)cmd;
+	int i;
+	u32 cc;
+	u32 attrs;
+	unsigned int nr_handles;
+
+	if (len < TPM_HEADER_SIZE || !chip->nr_commands)
+		return -EINVAL;
+
+	cc = be32_to_cpu(header->ordinal);
+
+	i = tpm2_find_cc(chip, cc);
+	if (i < 0) {
+		dev_dbg(&chip->dev, "0x%04X is an invalid command\n",
+			cc);
+		return -EOPNOTSUPP;
+	}
+
+	attrs = chip->cc_attrs_tbl[i];
+	nr_handles =
+		4 * ((attrs >> TPM2_CC_ATTR_CHANDLES) & GENMASK(2, 0));
+	if (len < TPM_HEADER_SIZE + 4 * nr_handles)
+		goto err_len;
+
+	return cc;
+err_len:
+	dev_dbg(&chip->dev, "%s: insufficient command length %zu", __func__,
+		len);
+	return -EINVAL;
+}
+
+int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u8 *cmd,
+		       size_t cmdsiz)
 {
 	int rc;
+	int cc;
 
 	if (!space)
 		return 0;
 
+	cc = tpm_find_and_validate_cc(chip, space, cmd, cmdsiz);
+	if (cc < 0)
+		return cc;
+
 	memcpy(&chip->work_space.context_tbl, &space->context_tbl,
 	       sizeof(space->context_tbl));
 	memcpy(&chip->work_space.session_tbl, &space->session_tbl,
@@ -291,6 +331,7 @@ int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u32 cc,
 		return rc;
 	}
 
+	chip->last_cc = cc;
 	return 0;
 }
 
@@ -490,7 +531,7 @@ static int tpm2_save_space(struct tpm_chip *chip)
 }
 
 int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space,
-		      u32 cc, void *buf, size_t *bufsiz)
+		      void *buf, size_t *bufsiz)
 {
 	struct tpm_header *header = buf;
 	int rc;
@@ -498,13 +539,13 @@ int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space,
 	if (!space)
 		return 0;
 
-	rc = tpm2_map_response_header(chip, cc, buf, *bufsiz);
+	rc = tpm2_map_response_header(chip, chip->last_cc, buf, *bufsiz);
 	if (rc) {
 		tpm2_flush_space(chip);
 		goto out;
 	}
 
-	rc = tpm2_map_response_body(chip, cc, buf, *bufsiz);
+	rc = tpm2_map_response_body(chip, chip->last_cc, buf, *bufsiz);
 	if (rc) {
 		tpm2_flush_space(chip);
 		goto out;