KEYS: trusted: Move TPM2 trusted keys code

Move TPM2 trusted keys code to trusted keys subsystem. The reason
being it's better to consolidate all the trusted keys code to a single
location so that it can be maintained sanely.

Also, utilize existing tpm_send() exported API which wraps the internal
tpm_transmit_cmd() API.
Suggested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
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>

drivers/char/tpm/tpm-interface.c

@@ -459,62 +459,6 @@ int tpm_get_random(struct tpm_chip *chip, u8 *out, size_t max)
 }
 EXPORT_SYMBOL_GPL(tpm_get_random);
 
-/**
- * tpm_seal_trusted() - seal a trusted key payload
- * @chip:	a &struct tpm_chip instance, %NULL for the default chip
- * @options:	authentication values and other options
- * @payload:	the key data in clear and encrypted form
- *
- * Note: only TPM 2.0 chip are supported. TPM 1.x implementation is located in
- * the keyring subsystem.
- *
- * Return: same as with tpm_transmit_cmd()
- */
-int tpm_seal_trusted(struct tpm_chip *chip, struct trusted_key_payload *payload,
-		     struct trusted_key_options *options)
-{
-	int rc;
-
-	chip = tpm_find_get_ops(chip);
-	if (!chip || !(chip->flags & TPM_CHIP_FLAG_TPM2))
-		return -ENODEV;
-
-	rc = tpm2_seal_trusted(chip, payload, options);
-
-	tpm_put_ops(chip);
-	return rc;
-}
-EXPORT_SYMBOL_GPL(tpm_seal_trusted);
-
-/**
- * tpm_unseal_trusted() - unseal a trusted key
- * @chip:	a &struct tpm_chip instance, %NULL for the default chip
- * @options:	authentication values and other options
- * @payload:	the key data in clear and encrypted form
- *
- * Note: only TPM 2.0 chip are supported. TPM 1.x implementation is located in
- * the keyring subsystem.
- *
- * Return: same as with tpm_transmit_cmd()
- */
-int tpm_unseal_trusted(struct tpm_chip *chip,
-		       struct trusted_key_payload *payload,
-		       struct trusted_key_options *options)
-{
-	int rc;
-
-	chip = tpm_find_get_ops(chip);
-	if (!chip || !(chip->flags & TPM_CHIP_FLAG_TPM2))
-		return -ENODEV;
-
-	rc = tpm2_unseal_trusted(chip, payload, options);
-
-	tpm_put_ops(chip);
-
-	return rc;
-}
-EXPORT_SYMBOL_GPL(tpm_unseal_trusted);
-
 static int __init tpm_init(void)
 {
 	int rc;

drivers/char/tpm/tpm.h

@@ -212,11 +212,6 @@ static inline void tpm_add_ppi(struct tpm_chip *chip)
 }
 #endif
 
-static inline u32 tpm2_rc_value(u32 rc)
-{
-	return (rc & BIT(7)) ? rc & 0xff : rc;
-}
-
 int tpm2_get_timeouts(struct tpm_chip *chip);
 int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
 		  struct tpm_digest *digest, u16 *digest_size_ptr);
@@ -224,12 +219,6 @@ int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
 		    struct tpm_digest *digests);
 int tpm2_get_random(struct tpm_chip *chip, u8 *dest, size_t max);
 void tpm2_flush_context(struct tpm_chip *chip, u32 handle);
-int tpm2_seal_trusted(struct tpm_chip *chip,
-		      struct trusted_key_payload *payload,
-		      struct trusted_key_options *options);
-int tpm2_unseal_trusted(struct tpm_chip *chip,
-			struct trusted_key_payload *payload,
-			struct trusted_key_options *options);
 ssize_t tpm2_get_tpm_pt(struct tpm_chip *chip, u32 property_id,
 			u32 *value, const char *desc);
 

drivers/char/tpm/tpm2-cmd.c

@@ -13,20 +13,6 @@
 
 #include "tpm.h"
 #include <crypto/hash_info.h>
-#include <keys/trusted-type.h>
-
-enum tpm2_object_attributes {
-	TPM2_OA_USER_WITH_AUTH		= BIT(6),
-};
-
-enum tpm2_session_attributes {
-	TPM2_SA_CONTINUE_SESSION	= BIT(0),
-};
-
-struct tpm2_hash {
-	unsigned int crypto_id;
-	unsigned int tpm_id;
-};
 
 static struct tpm2_hash tpm2_hash_map[] = {
 	{HASH_ALGO_SHA1, TPM_ALG_SHA1},
@@ -377,299 +363,6 @@ void tpm2_flush_context(struct tpm_chip *chip, u32 handle)
 	tpm_buf_destroy(&buf);
 }
 
-/**
- * tpm_buf_append_auth() - append TPMS_AUTH_COMMAND to the buffer.
- *
- * @buf: an allocated tpm_buf instance
- * @session_handle: session handle
- * @nonce: the session nonce, may be NULL if not used
- * @nonce_len: the session nonce length, may be 0 if not used
- * @attributes: the session attributes
- * @hmac: the session HMAC or password, may be NULL if not used
- * @hmac_len: the session HMAC or password length, maybe 0 if not used
- */
-static void tpm2_buf_append_auth(struct tpm_buf *buf, u32 session_handle,
-				 const u8 *nonce, u16 nonce_len,
-				 u8 attributes,
-				 const u8 *hmac, u16 hmac_len)
-{
-	tpm_buf_append_u32(buf, 9 + nonce_len + hmac_len);
-	tpm_buf_append_u32(buf, session_handle);
-	tpm_buf_append_u16(buf, nonce_len);
-
-	if (nonce && nonce_len)
-		tpm_buf_append(buf, nonce, nonce_len);
-
-	tpm_buf_append_u8(buf, attributes);
-	tpm_buf_append_u16(buf, hmac_len);
-
-	if (hmac && hmac_len)
-		tpm_buf_append(buf, hmac, hmac_len);
-}
-
-/**
- * tpm2_seal_trusted() - seal the payload of a trusted key
- *
- * @chip: TPM chip to use
- * @payload: the key data in clear and encrypted form
- * @options: authentication values and other options
- *
- * Return: < 0 on error and 0 on success.
- */
-int tpm2_seal_trusted(struct tpm_chip *chip,
-		      struct trusted_key_payload *payload,
-		      struct trusted_key_options *options)
-{
-	unsigned int blob_len;
-	struct tpm_buf buf;
-	u32 hash;
-	int i;
-	int rc;
-
-	for (i = 0; i < ARRAY_SIZE(tpm2_hash_map); i++) {
-		if (options->hash == tpm2_hash_map[i].crypto_id) {
-			hash = tpm2_hash_map[i].tpm_id;
-			break;
-		}
-	}
-
-	if (i == ARRAY_SIZE(tpm2_hash_map))
-		return -EINVAL;
-
-	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_CREATE);
-	if (rc)
-		return rc;
-
-	tpm_buf_append_u32(&buf, options->keyhandle);
-	tpm2_buf_append_auth(&buf, TPM2_RS_PW,
-			     NULL /* nonce */, 0,
-			     0 /* session_attributes */,
-			     options->keyauth /* hmac */,
-			     TPM_DIGEST_SIZE);
-
-	/* sensitive */
-	tpm_buf_append_u16(&buf, 4 + TPM_DIGEST_SIZE + payload->key_len + 1);
-
-	tpm_buf_append_u16(&buf, TPM_DIGEST_SIZE);
-	tpm_buf_append(&buf, options->blobauth, TPM_DIGEST_SIZE);
-	tpm_buf_append_u16(&buf, payload->key_len + 1);
-	tpm_buf_append(&buf, payload->key, payload->key_len);
-	tpm_buf_append_u8(&buf, payload->migratable);
-
-	/* public */
-	tpm_buf_append_u16(&buf, 14 + options->policydigest_len);
-	tpm_buf_append_u16(&buf, TPM_ALG_KEYEDHASH);
-	tpm_buf_append_u16(&buf, hash);
-
-	/* policy */
-	if (options->policydigest_len) {
-		tpm_buf_append_u32(&buf, 0);
-		tpm_buf_append_u16(&buf, options->policydigest_len);
-		tpm_buf_append(&buf, options->policydigest,
-			       options->policydigest_len);
-	} else {
-		tpm_buf_append_u32(&buf, TPM2_OA_USER_WITH_AUTH);
-		tpm_buf_append_u16(&buf, 0);
-	}
-
-	/* public parameters */
-	tpm_buf_append_u16(&buf, TPM_ALG_NULL);
-	tpm_buf_append_u16(&buf, 0);
-
-	/* outside info */
-	tpm_buf_append_u16(&buf, 0);
-
-	/* creation PCR */
-	tpm_buf_append_u32(&buf, 0);
-
-	if (buf.flags & TPM_BUF_OVERFLOW) {
-		rc = -E2BIG;
-		goto out;
-	}
-
-	rc = tpm_transmit_cmd(chip, &buf, 4, "sealing data");
-	if (rc)
-		goto out;
-
-	blob_len = be32_to_cpup((__be32 *) &buf.data[TPM_HEADER_SIZE]);
-	if (blob_len > MAX_BLOB_SIZE) {
-		rc = -E2BIG;
-		goto out;
-	}
-	if (tpm_buf_length(&buf) < TPM_HEADER_SIZE + 4 + blob_len) {
-		rc = -EFAULT;
-		goto out;
-	}
-
-	memcpy(payload->blob, &buf.data[TPM_HEADER_SIZE + 4], blob_len);
-	payload->blob_len = blob_len;
-
-out:
-	tpm_buf_destroy(&buf);
-
-	if (rc > 0) {
-		if (tpm2_rc_value(rc) == TPM2_RC_HASH)
-			rc = -EINVAL;
-		else
-			rc = -EPERM;
-	}
-
-	return rc;
-}
-
-/**
- * tpm2_load_cmd() - execute a TPM2_Load command
- *
- * @chip: TPM chip to use
- * @payload: the key data in clear and encrypted form
- * @options: authentication values and other options
- * @blob_handle: returned blob handle
- *
- * Return: 0 on success.
- *        -E2BIG on wrong payload size.
- *        -EPERM on tpm error status.
- *        < 0 error from tpm_transmit_cmd.
- */
-static int tpm2_load_cmd(struct tpm_chip *chip,
-			 struct trusted_key_payload *payload,
-			 struct trusted_key_options *options,
-			 u32 *blob_handle)
-{
-	struct tpm_buf buf;
-	unsigned int private_len;
-	unsigned int public_len;
-	unsigned int blob_len;
-	int rc;
-
-	private_len = be16_to_cpup((__be16 *) &payload->blob[0]);
-	if (private_len > (payload->blob_len - 2))
-		return -E2BIG;
-
-	public_len = be16_to_cpup((__be16 *) &payload->blob[2 + private_len]);
-	blob_len = private_len + public_len + 4;
-	if (blob_len > payload->blob_len)
-		return -E2BIG;
-
-	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_LOAD);
-	if (rc)
-		return rc;
-
-	tpm_buf_append_u32(&buf, options->keyhandle);
-	tpm2_buf_append_auth(&buf, TPM2_RS_PW,
-			     NULL /* nonce */, 0,
-			     0 /* session_attributes */,
-			     options->keyauth /* hmac */,
-			     TPM_DIGEST_SIZE);
-
-	tpm_buf_append(&buf, payload->blob, blob_len);
-
-	if (buf.flags & TPM_BUF_OVERFLOW) {
-		rc = -E2BIG;
-		goto out;
-	}
-
-	rc = tpm_transmit_cmd(chip, &buf, 4, "loading blob");
-	if (!rc)
-		*blob_handle = be32_to_cpup(
-			(__be32 *) &buf.data[TPM_HEADER_SIZE]);
-
-out:
-	tpm_buf_destroy(&buf);
-
-	if (rc > 0)
-		rc = -EPERM;
-
-	return rc;
-}
-
-/**
- * tpm2_unseal_cmd() - execute a TPM2_Unload command
- *
- * @chip: TPM chip to use
- * @payload: the key data in clear and encrypted form
- * @options: authentication values and other options
- * @blob_handle: blob handle
- *
- * Return: 0 on success
- *         -EPERM on tpm error status
- *         < 0 error from tpm_transmit_cmd
- */
-static int tpm2_unseal_cmd(struct tpm_chip *chip,
-			   struct trusted_key_payload *payload,
-			   struct trusted_key_options *options,
-			   u32 blob_handle)
-{
-	struct tpm_buf buf;
-	u16 data_len;
-	u8 *data;
-	int rc;
-
-	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_UNSEAL);
-	if (rc)
-		return rc;
-
-	tpm_buf_append_u32(&buf, blob_handle);
-	tpm2_buf_append_auth(&buf,
-			     options->policyhandle ?
-			     options->policyhandle : TPM2_RS_PW,
-			     NULL /* nonce */, 0,
-			     TPM2_SA_CONTINUE_SESSION,
-			     options->blobauth /* hmac */,
-			     TPM_DIGEST_SIZE);
-
-	rc = tpm_transmit_cmd(chip, &buf, 6, "unsealing");
-	if (rc > 0)
-		rc = -EPERM;
-
-	if (!rc) {
-		data_len = be16_to_cpup(
-			(__be16 *) &buf.data[TPM_HEADER_SIZE + 4]);
-		if (data_len < MIN_KEY_SIZE ||  data_len > MAX_KEY_SIZE + 1) {
-			rc = -EFAULT;
-			goto out;
-		}
-
-		if (tpm_buf_length(&buf) < TPM_HEADER_SIZE + 6 + data_len) {
-			rc = -EFAULT;
-			goto out;
-		}
-		data = &buf.data[TPM_HEADER_SIZE + 6];
-
-		memcpy(payload->key, data, data_len - 1);
-		payload->key_len = data_len - 1;
-		payload->migratable = data[data_len - 1];
-	}
-
-out:
-	tpm_buf_destroy(&buf);
-	return rc;
-}
-
-/**
- * tpm2_unseal_trusted() - unseal the payload of a trusted key
- *
- * @chip: TPM chip to use
- * @payload: the key data in clear and encrypted form
- * @options: authentication values and other options
- *
- * Return: Same as with tpm_transmit_cmd.
- */
-int tpm2_unseal_trusted(struct tpm_chip *chip,
-			struct trusted_key_payload *payload,
-			struct trusted_key_options *options)
-{
-	u32 blob_handle;
-	int rc;
-
-	rc = tpm2_load_cmd(chip, payload, options, &blob_handle);
-	if (rc)
-		return rc;
-
-	rc = tpm2_unseal_cmd(chip, payload, options, blob_handle);
-	tpm2_flush_context(chip, blob_handle);
-	return rc;
-}
-
 struct tpm2_get_cap_out {
 	u8 more_data;
 	__be32 subcap_id;

include/keys/trusted_tpm.h

@@ -40,6 +40,13 @@ int TSS_checkhmac1(unsigned char *buffer,
 int trusted_tpm_send(unsigned char *cmd, size_t buflen);
 int oiap(struct tpm_buf *tb, uint32_t *handle, unsigned char *nonce);
 
+int tpm2_seal_trusted(struct tpm_chip *chip,
+		      struct trusted_key_payload *payload,
+		      struct trusted_key_options *options);
+int tpm2_unseal_trusted(struct tpm_chip *chip,
+			struct trusted_key_payload *payload,
+			struct trusted_key_options *options);
+
 #define TPM_DEBUG 0
 
 #if TPM_DEBUG

include/linux/tpm.h

@@ -296,6 +296,19 @@ struct tpm_buf {
 	u8 *data;
 };
 
+enum tpm2_object_attributes {
+	TPM2_OA_USER_WITH_AUTH		= BIT(6),
+};
+
+enum tpm2_session_attributes {
+	TPM2_SA_CONTINUE_SESSION	= BIT(0),
+};
+
+struct tpm2_hash {
+	unsigned int crypto_id;
+	unsigned int tpm_id;
+};
+
 static inline void tpm_buf_reset(struct tpm_buf *buf, u16 tag, u32 ordinal)
 {
 	struct tpm_header *head = (struct tpm_header *)buf->data;
@@ -375,6 +388,11 @@ static inline void tpm_buf_append_u32(struct tpm_buf *buf, const u32 value)
 	tpm_buf_append(buf, (u8 *) &value2, 4);
 }
 
+static inline u32 tpm2_rc_value(u32 rc)
+{
+	return (rc & BIT(7)) ? rc & 0xff : rc;
+}
+
 #if defined(CONFIG_TCG_TPM) || defined(CONFIG_TCG_TPM_MODULE)
 
 extern int tpm_is_tpm2(struct tpm_chip *chip);
@@ -384,12 +402,6 @@ extern int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
 			  struct tpm_digest *digests);
 extern int tpm_send(struct tpm_chip *chip, void *cmd, size_t buflen);
 extern int tpm_get_random(struct tpm_chip *chip, u8 *data, size_t max);
-extern int tpm_seal_trusted(struct tpm_chip *chip,
-			    struct trusted_key_payload *payload,
-			    struct trusted_key_options *options);
-extern int tpm_unseal_trusted(struct tpm_chip *chip,
-			      struct trusted_key_payload *payload,
-			      struct trusted_key_options *options);
 extern struct tpm_chip *tpm_default_chip(void);
 #else
 static inline int tpm_is_tpm2(struct tpm_chip *chip)
@@ -418,18 +430,6 @@ static inline int tpm_get_random(struct tpm_chip *chip, u8 *data, size_t max)
 	return -ENODEV;
 }
 
-static inline int tpm_seal_trusted(struct tpm_chip *chip,
-				   struct trusted_key_payload *payload,
-				   struct trusted_key_options *options)
-{
-	return -ENODEV;
-}
-static inline int tpm_unseal_trusted(struct tpm_chip *chip,
-				     struct trusted_key_payload *payload,
-				     struct trusted_key_options *options)
-{
-	return -ENODEV;
-}
 static inline struct tpm_chip *tpm_default_chip(void)
 {
 	return NULL;

security/keys/trusted-keys/Makefile

@@ -5,3 +5,4 @@
 
 obj-$(CONFIG_TRUSTED_KEYS) += trusted.o
 trusted-y += trusted_tpm1.o
+trusted-y += trusted_tpm2.o

security/keys/trusted-keys/trusted_tpm1.c

@@ -1004,7 +1004,7 @@ static int trusted_instantiate(struct key *key,
 	switch (key_cmd) {
 	case Opt_load:
 		if (tpm2)
-			ret = tpm_unseal_trusted(chip, payload, options);
+			ret = tpm2_unseal_trusted(chip, payload, options);
 		else
 			ret = key_unseal(payload, options);
 		dump_payload(payload);
@@ -1020,7 +1020,7 @@ static int trusted_instantiate(struct key *key,
 			goto out;
 		}
 		if (tpm2)
-			ret = tpm_seal_trusted(chip, payload, options);
+			ret = tpm2_seal_trusted(chip, payload, options);
 		else
 			ret = key_seal(payload, options);
 		if (ret < 0)

security/keys/trusted-keys/trusted_tpm2.c

+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2004 IBM Corporation
+ * Copyright (C) 2014 Intel Corporation
+ */
+
+#include <linux/string.h>
+#include <linux/err.h>
+#include <linux/tpm.h>
+#include <linux/tpm_command.h>
+
+#include <keys/trusted-type.h>
+#include <keys/trusted_tpm.h>
+
+static struct tpm2_hash tpm2_hash_map[] = {
+	{HASH_ALGO_SHA1, TPM_ALG_SHA1},
+	{HASH_ALGO_SHA256, TPM_ALG_SHA256},
+	{HASH_ALGO_SHA384, TPM_ALG_SHA384},
+	{HASH_ALGO_SHA512, TPM_ALG_SHA512},
+	{HASH_ALGO_SM3_256, TPM_ALG_SM3_256},
+};
+
+/**
+ * tpm_buf_append_auth() - append TPMS_AUTH_COMMAND to the buffer.
+ *
+ * @buf: an allocated tpm_buf instance
+ * @session_handle: session handle
+ * @nonce: the session nonce, may be NULL if not used
+ * @nonce_len: the session nonce length, may be 0 if not used
+ * @attributes: the session attributes
+ * @hmac: the session HMAC or password, may be NULL if not used
+ * @hmac_len: the session HMAC or password length, maybe 0 if not used
+ */
+static void tpm2_buf_append_auth(struct tpm_buf *buf, u32 session_handle,
+				 const u8 *nonce, u16 nonce_len,
+				 u8 attributes,
+				 const u8 *hmac, u16 hmac_len)
+{
+	tpm_buf_append_u32(buf, 9 + nonce_len + hmac_len);
+	tpm_buf_append_u32(buf, session_handle);
+	tpm_buf_append_u16(buf, nonce_len);
+
+	if (nonce && nonce_len)
+		tpm_buf_append(buf, nonce, nonce_len);
+
+	tpm_buf_append_u8(buf, attributes);
+	tpm_buf_append_u16(buf, hmac_len);
+
+	if (hmac && hmac_len)
+		tpm_buf_append(buf, hmac, hmac_len);
+}
+
+/**
+ * tpm2_seal_trusted() - seal the payload of a trusted key
+ *
+ * @chip: TPM chip to use
+ * @payload: the key data in clear and encrypted form
+ * @options: authentication values and other options
+ *
+ * Return: < 0 on error and 0 on success.
+ */
+int tpm2_seal_trusted(struct tpm_chip *chip,
+		      struct trusted_key_payload *payload,
+		      struct trusted_key_options *options)
+{
+	unsigned int blob_len;
+	struct tpm_buf buf;
+	u32 hash;
+	int i;
+	int rc;
+
+	for (i = 0; i < ARRAY_SIZE(tpm2_hash_map); i++) {
+		if (options->hash == tpm2_hash_map[i].crypto_id) {
+			hash = tpm2_hash_map[i].tpm_id;
+			break;
+		}
+	}
+
+	if (i == ARRAY_SIZE(tpm2_hash_map))
+		return -EINVAL;
+
+	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_CREATE);
+	if (rc)
+		return rc;
+
+	tpm_buf_append_u32(&buf, options->keyhandle);
+	tpm2_buf_append_auth(&buf, TPM2_RS_PW,
+			     NULL /* nonce */, 0,
+			     0 /* session_attributes */,
+			     options->keyauth /* hmac */,
+			     TPM_DIGEST_SIZE);
+
+	/* sensitive */
+	tpm_buf_append_u16(&buf, 4 + TPM_DIGEST_SIZE + payload->key_len + 1);
+
+	tpm_buf_append_u16(&buf, TPM_DIGEST_SIZE);
+	tpm_buf_append(&buf, options->blobauth, TPM_DIGEST_SIZE);
+	tpm_buf_append_u16(&buf, payload->key_len + 1);
+	tpm_buf_append(&buf, payload->key, payload->key_len);
+	tpm_buf_append_u8(&buf, payload->migratable);
+
+	/* public */
+	tpm_buf_append_u16(&buf, 14 + options->policydigest_len);
+	tpm_buf_append_u16(&buf, TPM_ALG_KEYEDHASH);
+	tpm_buf_append_u16(&buf, hash);
+
+	/* policy */
+	if (options->policydigest_len) {
+		tpm_buf_append_u32(&buf, 0);
+		tpm_buf_append_u16(&buf, options->policydigest_len);
+		tpm_buf_append(&buf, options->policydigest,
+			       options->policydigest_len);
+	} else {
+		tpm_buf_append_u32(&buf, TPM2_OA_USER_WITH_AUTH);
+		tpm_buf_append_u16(&buf, 0);
+	}
+
+	/* public parameters */
+	tpm_buf_append_u16(&buf, TPM_ALG_NULL);
+	tpm_buf_append_u16(&buf, 0);
+
+	/* outside info */
+	tpm_buf_append_u16(&buf, 0);
+
+	/* creation PCR */
+	tpm_buf_append_u32(&buf, 0);
+
+	if (buf.flags & TPM_BUF_OVERFLOW) {
+		rc = -E2BIG;
+		goto out;
+	}
+
+	rc = tpm_send(chip, buf.data, tpm_buf_length(&buf));
+	if (rc)
+		goto out;
+
+	blob_len = be32_to_cpup((__be32 *) &buf.data[TPM_HEADER_SIZE]);
+	if (blob_len > MAX_BLOB_SIZE) {
+		rc = -E2BIG;
+		goto out;
+	}
+	if (tpm_buf_length(&buf) < TPM_HEADER_SIZE + 4 + blob_len) {
+		rc = -EFAULT;
+		goto out;
+	}
+
+	memcpy(payload->blob, &buf.data[TPM_HEADER_SIZE + 4], blob_len);
+	payload->blob_len = blob_len;
+
+out:
+	tpm_buf_destroy(&buf);
+
+	if (rc > 0) {
+		if (tpm2_rc_value(rc) == TPM2_RC_HASH)
+			rc = -EINVAL;
+		else
+			rc = -EPERM;
+	}
+
+	return rc;
+}
+
+/**
+ * tpm2_load_cmd() - execute a TPM2_Load command
+ *
+ * @chip: TPM chip to use
+ * @payload: the key data in clear and encrypted form
+ * @options: authentication values and other options
+ * @blob_handle: returned blob handle
+ *
+ * Return: 0 on success.
+ *        -E2BIG on wrong payload size.
+ *        -EPERM on tpm error status.
+ *        < 0 error from tpm_send.
+ */
+static int tpm2_load_cmd(struct tpm_chip *chip,
+			 struct trusted_key_payload *payload,
+			 struct trusted_key_options *options,
+			 u32 *blob_handle)
+{
+	struct tpm_buf buf;
+	unsigned int private_len;
+	unsigned int public_len;
+	unsigned int blob_len;
+	int rc;
+
+	private_len = be16_to_cpup((__be16 *) &payload->blob[0]);
+	if (private_len > (payload->blob_len - 2))
+		return -E2BIG;
+
+	public_len = be16_to_cpup((__be16 *) &payload->blob[2 + private_len]);
+	blob_len = private_len + public_len + 4;
+	if (blob_len > payload->blob_len)
+		return -E2BIG;
+
+	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_LOAD);
+	if (rc)
+		return rc;
+
+	tpm_buf_append_u32(&buf, options->keyhandle);
+	tpm2_buf_append_auth(&buf, TPM2_RS_PW,
+			     NULL /* nonce */, 0,
+			     0 /* session_attributes */,
+			     options->keyauth /* hmac */,
+			     TPM_DIGEST_SIZE);
+
+	tpm_buf_append(&buf, payload->blob, blob_len);
+
+	if (buf.flags & TPM_BUF_OVERFLOW) {
+		rc = -E2BIG;
+		goto out;
+	}
+
+	rc = tpm_send(chip, buf.data, tpm_buf_length(&buf));
+	if (!rc)
+		*blob_handle = be32_to_cpup(
+			(__be32 *) &buf.data[TPM_HEADER_SIZE]);
+
+out:
+	tpm_buf_destroy(&buf);
+
+	if (rc > 0)
+		rc = -EPERM;
+
+	return rc;
+}
+
+/**
+ * tpm2_unseal_cmd() - execute a TPM2_Unload command
+ *
+ * @chip: TPM chip to use
+ * @payload: the key data in clear and encrypted form
+ * @options: authentication values and other options
+ * @blob_handle: blob handle
+ *
+ * Return: 0 on success
+ *         -EPERM on tpm error status
+ *         < 0 error from tpm_send
+ */
+static int tpm2_unseal_cmd(struct tpm_chip *chip,
+			   struct trusted_key_payload *payload,
+			   struct trusted_key_options *options,
+			   u32 blob_handle)
+{
+	struct tpm_buf buf;
+	u16 data_len;
+	u8 *data;
+	int rc;
+
+	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_UNSEAL);
+	if (rc)
+		return rc;
+
+	tpm_buf_append_u32(&buf, blob_handle);
+	tpm2_buf_append_auth(&buf,
+			     options->policyhandle ?
+			     options->policyhandle : TPM2_RS_PW,
+			     NULL /* nonce */, 0,
+			     TPM2_SA_CONTINUE_SESSION,
+			     options->blobauth /* hmac */,
+			     TPM_DIGEST_SIZE);
+
+	rc = tpm_send(chip, buf.data, tpm_buf_length(&buf));
+	if (rc > 0)
+		rc = -EPERM;
+
+	if (!rc) {
+		data_len = be16_to_cpup(
+			(__be16 *) &buf.data[TPM_HEADER_SIZE + 4]);
+		if (data_len < MIN_KEY_SIZE ||  data_len > MAX_KEY_SIZE + 1) {
+			rc = -EFAULT;
+			goto out;
+		}
+
+		if (tpm_buf_length(&buf) < TPM_HEADER_SIZE + 6 + data_len) {
+			rc = -EFAULT;
+			goto out;
+		}
+		data = &buf.data[TPM_HEADER_SIZE + 6];
+
+		memcpy(payload->key, data, data_len - 1);
+		payload->key_len = data_len - 1;
+		payload->migratable = data[data_len - 1];
+	}
+
+out:
+	tpm_buf_destroy(&buf);
+	return rc;
+}
+
+/**
+ * tpm2_unseal_trusted() - unseal the payload of a trusted key
+ *
+ * @chip: TPM chip to use
+ * @payload: the key data in clear and encrypted form
+ * @options: authentication values and other options
+ *
+ * Return: Same as with tpm_send.
+ */
+int tpm2_unseal_trusted(struct tpm_chip *chip,
+			struct trusted_key_payload *payload,
+			struct trusted_key_options *options)
+{
+	u32 blob_handle;
+	int rc;
+
+	rc = tpm2_load_cmd(chip, payload, options, &blob_handle);
+	if (rc)
+		return rc;
+
+	rc = tpm2_unseal_cmd(chip, payload, options, blob_handle);
+
+	return rc;
+}