diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 403d332..fe863f2 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -328,6 +328,36 @@ unsigned long tpm_calc_ordinal_duration(struct tpm_chip *chip,
 }
 EXPORT_SYMBOL_GPL(tpm_calc_ordinal_duration);
 
+static bool tpm_validate_command(struct tpm_chip *chip, const u8 *cmd,
+				 size_t len)
+{
+	const struct tpm_input_header *header = (const void *)cmd;
+	u32 cc;
+	size_t len_min = TPM_HEADER_SIZE;
+	u32 attrs;
+
+	if ((len >= len_min) && (chip->flags & TPM_CHIP_FLAG_TPM2) &&
+	    chip->nr_commands) {
+		cc = be32_to_cpu(header->ordinal);
+		if (!tpm2_find_cc_attrs(chip, cc, &attrs)) {
+			dev_dbg(&chip->dev, "0x%04x is an invalid command\n",
+				cc);
+			return false;
+		}
+		len_min +=
+			4 * ((attrs >> TPM2_CC_ATTR_CHANDLES) & GENMASK(2, 0));
+	}
+
+	if (len < len_min) {
+		dev_dbg(&chip->dev,
+			"%s: insufficient command length %zu < %zu\n",
+			__func__, len, len_min);
+		return false;
+	}
+
+	return true;
+}
+
 /**
  * tmp_transmit - Internal kernel interface to transmit TPM commands.
  *
@@ -347,7 +377,7 @@ ssize_t tpm_transmit(struct tpm_chip *chip, const u8 *buf, size_t bufsiz,
 	u32 count, ordinal;
 	unsigned long stop;
 
-	if (bufsiz < TPM_HEADER_SIZE)
+	if (!tpm_validate_command(chip, buf, bufsiz))
 		return -EINVAL;
 
 	if (bufsiz > TPM_BUFSIZE)
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 9e81865..52d805f 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -127,7 +127,12 @@ enum tpm2_permanent_handles {
 };
 
 enum tpm2_capabilities {
-	TPM2_CAP_TPM_PROPERTIES = 6,
+	TPM2_CAP_COMMANDS	= 2,
+	TPM2_CAP_TPM_PROPERTIES	= 6,
+};
+
+enum tpm2_properties {
+	TPM_PT_TOTAL_COMMANDS	= 0x0129,
 };
 
 enum tpm2_startup_types {
@@ -135,6 +140,11 @@ enum tpm2_startup_types {
 	TPM2_SU_STATE	= 0x0001,
 };
 
+enum tpm2_cc_attrs {
+	TPM2_CC_ATTR_CHANDLES	= 25,
+	TPM2_CC_ATTR_RHANDLE	= 28,
+};
+
 #define TPM_VID_INTEL    0x8086
 #define TPM_VID_WINBOND  0x1050
 #define TPM_VID_STM      0x104A
@@ -191,6 +201,9 @@ struct tpm_chip {
 	acpi_handle acpi_dev_handle;
 	char ppi_version[TPM_PPI_VERSION_LEN + 1];
 #endif /* CONFIG_ACPI */
+
+	u32 nr_commands;
+	u32 *cc_attrs_tbl;
 };
 
 #define to_tpm_chip(d) container_of(d, struct tpm_chip, dev)
@@ -393,7 +406,8 @@ struct tpm_cmd_t {
  */
 
 enum tpm_buf_flags {
-	TPM_BUF_OVERFLOW	= BIT(0),
+	TPM_BUF_INITIALIZED	= BIT(0),
+	TPM_BUF_OVERFLOW	= BIT(1),
 };
 
 struct tpm_buf {
@@ -419,13 +433,17 @@ static inline int tpm_buf_init(struct tpm_buf *buf, u16 tag, u32 ordinal)
 	head->length = cpu_to_be32(sizeof(*head));
 	head->ordinal = cpu_to_be32(ordinal);
 
+	buf->flags = TPM_BUF_INITIALIZED;
+
 	return 0;
 }
 
 static inline void tpm_buf_destroy(struct tpm_buf *buf)
 {
-	kunmap(buf->data_page);
-	__free_page(buf->data_page);
+	if (buf->flags & TPM_BUF_INITIALIZED) {
+		kunmap(buf->data_page);
+		__free_page(buf->data_page);
+	}
 }
 
 static inline u32 tpm_buf_length(struct tpm_buf *buf)
@@ -546,4 +564,5 @@ int tpm2_auto_startup(struct tpm_chip *chip);
 void tpm2_shutdown(struct tpm_chip *chip, u16 shutdown_type);
 unsigned long tpm2_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal);
 int tpm2_probe(struct tpm_chip *chip);
+bool tpm2_find_cc_attrs(struct tpm_chip *chip, u32 cc, u32 *attrs);
 #endif
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 201538e..3dce7b7 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -1005,7 +1005,10 @@ EXPORT_SYMBOL_GPL(tpm2_probe);
  */
 int tpm2_auto_startup(struct tpm_chip *chip)
 {
+	struct tpm_buf buf;
+	u32 nr_commands;
 	int rc;
+	int i;
 
 	rc = tpm_get_timeouts(chip);
 	if (rc)
@@ -1029,8 +1032,56 @@ int tpm2_auto_startup(struct tpm_chip *chip)
 		}
 	}
 
+	rc = tpm2_get_tpm_pt(chip, TPM_PT_TOTAL_COMMANDS, &nr_commands, NULL);
+	if (rc)
+		goto out;
+
+	chip->cc_attrs_tbl = devm_kzalloc(&chip->dev, 4 * nr_commands,
+					  GFP_KERNEL);
+
+	rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_GET_CAPABILITY);
+	if (rc)
+		goto out;
+
+	tpm_buf_append_u32(&buf, TPM2_CAP_COMMANDS);
+	tpm_buf_append_u32(&buf, TPM2_CC_FIRST);
+	tpm_buf_append_u32(&buf, nr_commands);
+
+	rc = tpm_transmit_cmd(chip, buf.data, PAGE_SIZE, 0, NULL);
+	if (rc < 0) {
+		tpm_buf_destroy(&buf);
+		goto out;
+	}
+
+	if (nr_commands !=
+	    be32_to_cpup((__be32 *)&buf.data[TPM_HEADER_SIZE + 5])) {
+		tpm_buf_destroy(&buf);
+		goto out;
+	}
+
+	for (i = 0; i < nr_commands; i++)
+		chip->cc_attrs_tbl[i] = be32_to_cpup(
+			(u32 *)&buf.data[TPM_HEADER_SIZE + 9 + 4 * i]);
+
+	chip->nr_commands = nr_commands;
+	tpm_buf_destroy(&buf);
+
 out:
 	if (rc > 0)
 		rc = -ENODEV;
 	return rc;
 }
+
+bool tpm2_find_cc_attrs(struct tpm_chip *chip, u32 cc, u32 *attrs)
+{
+	int i;
+
+	for (i = 0; i < chip->nr_commands; i++) {
+		if (cc == (chip->cc_attrs_tbl[i] & GENMASK(15, 0))) {
+			*attrs = chip->cc_attrs_tbl[i];
+			return true;
+		}
+	}
+
+	return false;
+}