[PATCH v2 1/2] KEYS: trusted: Re-orchestrate tpm2_read_public() calls

[PATCH v2 1/2] KEYS: trusted: Re-orchestrate tpm2_read_public() calls

[Jarkko Sakkinen]

tpm2_load_cmd() and tpm2_unseal_cmd() use the same parent, and calls to
tpm_buf_append_name() cause the exact same TPM2_ReadPublic command to be
sent to the chip, causing unnecessary traffic.

1. Export tpm2_read_public in order to make it callable from
   'trusted_tpm2'.
2. Re-orchestrate tpm2_seal_trusted() and tpm2_unseal_trusted() in order to
   halve the name resolutions required:
2a. Move tpm2_read_public() calls into trusted_tpm2.
2b. Pass TPM name to tpm_buf_append_name().
2c. Rework tpm_buf_append_name() to use the pre-resolved name.

Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
---
v2: 
- No changes.
---
 drivers/char/tpm/tpm2-cmd.c               |   3 +-
 drivers/char/tpm/tpm2-sessions.c          |  95 +++++------------
 include/linux/tpm.h                       |  10 +-
 security/keys/trusted-keys/trusted_tpm2.c | 124 ++++++++++++++--------
 4 files changed, 118 insertions(+), 114 deletions(-)

diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 3a77be7ebf4a..1f561ad3bdcf 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -202,7 +202,8 @@ int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
 	}
 
 	if (!disable_pcr_integrity) {
-		rc = tpm_buf_append_name(chip, &buf, pcr_idx, NULL);
+		rc = tpm_buf_append_name(chip, &buf, pcr_idx, (u8 *)&pcr_idx,
+					 sizeof(u32));
 		if (rc) {
 			tpm_buf_destroy(&buf);
 			return rc;
diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c
index 4149379665c4..e33be09446ff 100644
--- a/drivers/char/tpm/tpm2-sessions.c
+++ b/drivers/char/tpm/tpm2-sessions.c
@@ -136,8 +136,8 @@ struct tpm2_auth {
 	 * handle, but they are part of the session by name, which
 	 * we must compute and remember
 	 */
-	u32 name_h[AUTH_MAX_NAMES];
 	u8 name[AUTH_MAX_NAMES][2 + SHA512_DIGEST_SIZE];
+	u16 name_size_tbl[AUTH_MAX_NAMES];
 };
 
 #ifdef CONFIG_TCG_TPM2_HMAC
@@ -163,7 +163,17 @@ static int name_size(const u8 *name)
 	}
 }
 
-static int tpm2_read_public(struct tpm_chip *chip, u32 handle, void *name)
+/**
+ * tpm2_read_public: Resolve TPM name for a handle
+ * @chip:		TPM chip to use.
+ * @handle:		TPM handle.
+ * @name:		A buffer for returning the name blob. Must have a
+ *			capacity of 'SHA512_DIGET_SIZE + 2' bytes at minimum
+ *
+ * Returns size of TPM handle name of success.
+ * Returns tpm_transmit_cmd error codes when TPM2_ReadPublic fails.
+ */
+int tpm2_read_public(struct tpm_chip *chip, u32 handle, void *name)
 {
 	u32 mso = tpm2_handle_mso(handle);
 	off_t offset = TPM_HEADER_SIZE;
@@ -219,14 +229,16 @@ static int tpm2_read_public(struct tpm_chip *chip, u32 handle, void *name)
 	memcpy(name, &buf.data[offset], rc);
 	return name_size_alg;
 }
+EXPORT_SYMBOL_GPL(tpm2_read_public);
 #endif /* CONFIG_TCG_TPM2_HMAC */
 
 /**
- * tpm_buf_append_name() - add a handle area to the buffer
- * @chip: the TPM chip structure
- * @buf: The buffer to be appended
- * @handle: The handle to be appended
- * @name: The name of the handle (may be NULL)
+ * tpm_buf_append_name() - Append a handle and store TPM name
+ * @chip:		TPM chip to use.
+ * @buf:		TPM buffer containing the TPM command in-transit.
+ * @handle:		TPM handle to be appended.
+ * @name:		TPM name of the handle
+ * @name_size:		Size of the TPM name.
  *
  * In order to compute session HMACs, we need to know the names of the
  * objects pointed to by the handles.  For most objects, this is simply
@@ -243,15 +255,14 @@ static int tpm2_read_public(struct tpm_chip *chip, u32 handle, void *name)
  * will be caused by an incorrect programming model and indicated by a
  * kernel message.
  *
- * Ends the authorization session on failure.
+ * Returns zero on success.
+ * Returns -EIO when the authorization area state is malformed.
  */
 int tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf,
-			u32 handle, u8 *name)
+			u32 handle, u8 *name, u16 name_size)
 {
 #ifdef CONFIG_TCG_TPM2_HMAC
-	enum tpm2_mso_type mso = tpm2_handle_mso(handle);
 	struct tpm2_auth *auth;
-	u16 name_size_alg;
 	int slot;
 	int ret;
 #endif
@@ -276,36 +287,15 @@ int tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf,
 	}
 	tpm_buf_append_u32(buf, handle);
 	auth->session += 4;
-
-	if (mso == TPM2_MSO_PERSISTENT ||
-	    mso == TPM2_MSO_VOLATILE ||
-	    mso == TPM2_MSO_NVRAM) {
-		if (!name) {
-			ret = tpm2_read_public(chip, handle, auth->name[slot]);
-			if (ret < 0)
-				goto err;
-
-			name_size_alg = ret;
-		}
-	} else {
-		if (name) {
-			dev_err(&chip->dev, "handle 0x%08x does not use a name\n",
-				handle);
-			ret = -EIO;
-			goto err;
-		}
-	}
-
-	auth->name_h[slot] = handle;
-	if (name)
-		memcpy(auth->name[slot], name, name_size_alg);
+	memcpy(auth->name[slot], name, name_size);
+	auth->name_size_tbl[slot] = name_size;
 #endif
 	return 0;
 
 #ifdef CONFIG_TCG_TPM2_HMAC
 err:
 	tpm2_end_auth_session(chip);
-	return tpm_ret_to_err(ret);
+	return ret;
 #endif
 }
 EXPORT_SYMBOL_GPL(tpm_buf_append_name);
@@ -613,22 +603,8 @@ int tpm_buf_fill_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf)
 	attrs = chip->cc_attrs_tbl[i];
 
 	handles = (attrs >> TPM2_CC_ATTR_CHANDLES) & GENMASK(2, 0);
+	offset_s += handles * sizeof(u32);
 
-	/*
-	 * just check the names, it's easy to make mistakes.  This
-	 * would happen if someone added a handle via
-	 * tpm_buf_append_u32() instead of tpm_buf_append_name()
-	 */
-	for (i = 0; i < handles; i++) {
-		u32 handle = tpm_buf_read_u32(buf, &offset_s);
-
-		if (auth->name_h[i] != handle) {
-			dev_err(&chip->dev, "invalid handle 0x%08x\n", handle);
-			ret = -EIO;
-			goto err;
-		}
-	}
-	/* point offset_s to the start of the sessions */
 	val = tpm_buf_read_u32(buf, &offset_s);
 	/* point offset_p to the start of the parameters */
 	offset_p = offset_s + val;
@@ -689,23 +665,8 @@ int tpm_buf_fill_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf)
 	/* ordinal is already BE */
 	sha256_update(&sctx, (u8 *)&head->ordinal, sizeof(head->ordinal));
 	/* add the handle names */
-	for (i = 0; i < handles; i++) {
-		enum tpm2_mso_type mso = tpm2_handle_mso(auth->name_h[i]);
-
-		if (mso == TPM2_MSO_PERSISTENT ||
-		    mso == TPM2_MSO_VOLATILE ||
-		    mso == TPM2_MSO_NVRAM) {
-			ret = name_size(auth->name[i]);
-			if (ret < 0)
-				goto err;
-
-			sha256_update(&sctx, auth->name[i], ret);
-		} else {
-			__be32 h = cpu_to_be32(auth->name_h[i]);
-
-			sha256_update(&sctx, (u8 *)&h, 4);
-		}
-	}
+	for (i = 0; i < handles; i++)
+		sha256_update(&sctx, auth->name[i], auth->name_size_tbl[i]);
 	if (offset_s != tpm_buf_length(buf))
 		sha256_update(&sctx, &buf->data[offset_s],
 			      tpm_buf_length(buf) - offset_s);
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index 202da079d500..319ba75dd79a 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -530,7 +530,7 @@ static inline struct tpm2_auth *tpm2_chip_auth(struct tpm_chip *chip)
 }
 
 int tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf,
-			u32 handle, u8 *name);
+			u32 handle, u8 *name, u16 name_size);
 void tpm_buf_append_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf,
 				 u8 attributes, u8 *passphrase,
 				 int passphraselen);
@@ -544,6 +544,7 @@ int tpm_buf_fill_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf);
 int tpm_buf_check_hmac_response(struct tpm_chip *chip, struct tpm_buf *buf,
 				int rc);
 void tpm2_end_auth_session(struct tpm_chip *chip);
+int tpm2_read_public(struct tpm_chip *chip, u32 handle, void *name);
 #else
 #include <linux/unaligned.h>
 
@@ -567,6 +568,13 @@ static inline int tpm_buf_check_hmac_response(struct tpm_chip *chip,
 {
 	return rc;
 }
+
+static inline int tpm2_read_public(struct tpm_chip *chip, u32 handle,
+				   void *name)
+{
+	memcpy(name, &handle, sizeof(u32));
+	return sizeof(u32);
+}
 #endif	/* CONFIG_TCG_TPM2_HMAC */
 
 #endif
diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c
index a7ea4a1c3bed..88bafbcc011a 100644
--- a/security/keys/trusted-keys/trusted_tpm2.c
+++ b/security/keys/trusted-keys/trusted_tpm2.c
@@ -233,8 +233,10 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
 		      struct trusted_key_payload *payload,
 		      struct trusted_key_options *options)
 {
+	u8 parent_name[2 + SHA512_DIGEST_SIZE];
 	off_t offset = TPM_HEADER_SIZE;
 	struct tpm_buf buf, sized;
+	u16 parent_name_size;
 	int blob_len = 0;
 	int hash;
 	u32 flags;
@@ -251,6 +253,12 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
 	if (rc)
 		return rc;
 
+	rc = tpm2_read_public(chip, options->keyhandle, parent_name);
+	if (rc < 0)
+		goto out_put;
+
+	parent_name_size = rc;
+
 	rc = tpm2_start_auth_session(chip);
 	if (rc)
 		goto out_put;
@@ -268,7 +276,8 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
 		goto out_put;
 	}
 
-	rc = tpm_buf_append_name(chip, &buf, options->keyhandle, NULL);
+	rc = tpm_buf_append_name(chip, &buf, options->keyhandle, parent_name,
+				 parent_name_size);
 	if (rc)
 		goto out;
 
@@ -355,21 +364,25 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
 }
 
 /**
- * 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
+ * tpm2_load_cmd() - Execute TPM2_Load
+ * @chip:		TPM chip to use.
+ * @payload:		Key data in clear text.
+ * @options:		Trusted key options.
+ * @parent_name:	A cryptographic name, i.e. a TPMT_HA blob, of the
+ *			parent key.
+ * @blob:		The decoded payload for the key.
+ * @blob_handle:	On success, will contain handle to the loaded keyedhash
+ *			blob.
  *
- * Return: 0 on success.
- *        -E2BIG on wrong payload size.
- *        -EPERM on tpm error status.
- *        < 0 error from tpm_send.
+ * Return -E2BIG when the blob size is too small for all the data.
+ * Returns tpm_transmit_cmd() error codes when either TPM2_Load fails.
  */
 static int tpm2_load_cmd(struct tpm_chip *chip,
 			 struct trusted_key_payload *payload,
 			 struct trusted_key_options *options,
+			 u8 *parent_name,
+			 u16 parent_name_size,
+			 const u8 *blob,
 			 u32 *blob_handle)
 {
 	u8 *blob_ref __free(kfree) = NULL;
@@ -377,27 +390,13 @@ static int tpm2_load_cmd(struct tpm_chip *chip,
 	unsigned int private_len;
 	unsigned int public_len;
 	unsigned int blob_len;
-	u8 *blob, *pub;
+	const u8 *pub;
 	int rc;
 	u32 attrs;
 
-	rc = tpm2_key_decode(payload, options, &blob);
-	if (rc) {
-		/* old form */
-		blob = payload->blob;
-		payload->old_format = 1;
-	} else {
-		/* Bind for cleanup: */
-		blob_ref = blob;
-	}
-
-	/* new format carries keyhandle but old format doesn't */
-	if (!options->keyhandle)
-		return -EINVAL;
-
 	/* must be big enough for at least the two be16 size counts */
 	if (payload->blob_len < 4)
-		return -EINVAL;
+		return -E2BIG;
 
 	private_len = get_unaligned_be16(blob);
 
@@ -433,7 +432,8 @@ static int tpm2_load_cmd(struct tpm_chip *chip,
 		return rc;
 	}
 
-	rc = tpm_buf_append_name(chip, &buf, options->keyhandle, NULL);
+	rc = tpm_buf_append_name(chip, &buf, options->keyhandle, parent_name,
+				 parent_name_size);
 	if (rc)
 		goto out;
 
@@ -465,20 +465,23 @@ static int tpm2_load_cmd(struct tpm_chip *chip,
 }
 
 /**
- * tpm2_unseal_cmd() - execute a TPM2_Unload command
+ * tpm2_unseal_cmd() - Execute TPM2_Unload
  *
- * @chip: TPM chip to use
- * @payload: the key data in clear and encrypted form
- * @options: authentication values and other options
- * @blob_handle: blob handle
+ * @chip:		TPM chip to use
+ * @payload:		Key data in clear text.
+ * @options:		Trusted key options.
+ * @parent_name:	A cryptographic name, i.e. a TPMT_HA blob, of the
+ *			parent key.
+ * @blob_handle:	Handle to the loaded keyedhash blob.
  *
- * Return: 0 on success
- *         -EPERM on tpm error status
- *         < 0 error from tpm_send
+ * Return -E2BIG when the blob size is too small for all the data.
+ * Returns tpm_transmit_cmd() error codes when either TPM2_Load fails.
  */
 static int tpm2_unseal_cmd(struct tpm_chip *chip,
 			   struct trusted_key_payload *payload,
 			   struct trusted_key_options *options,
+			   u8 *parent_name,
+			   u16 parent_name_size,
 			   u32 blob_handle)
 {
 	struct tpm_header *head;
@@ -498,7 +501,8 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
 		return rc;
 	}
 
-	rc = tpm_buf_append_name(chip, &buf, options->keyhandle, NULL);
+	rc = tpm_buf_append_name(chip, &buf, options->keyhandle, parent_name,
+				 parent_name_size);
 	if (rc)
 		goto out;
 
@@ -573,30 +577,60 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
 }
 
 /**
- * tpm2_unseal_trusted() - unseal the payload of a trusted key
+ * tpm2_unseal_trusted() - Unseal a trusted key
+ * @chip:	TPM chip to use.
+ * @payload:	Key data in clear text.
+ * @options:	Trusted key options.
  *
- * @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.
+ * Return -E2BIG when the blob size is too small for all the data.
+ * Return -EINVAL when parent's key handle has not been set.
+ * Returns tpm_transmit_cmd() error codes when either TPM2_Load or TPM2_Unseal
+ * fails.
  */
 int tpm2_unseal_trusted(struct tpm_chip *chip,
 			struct trusted_key_payload *payload,
 			struct trusted_key_options *options)
 {
+	u8 *blob_ref __free(kfree) = NULL;
+	u8 parent_name[2 + SHA512_DIGEST_SIZE];
+	u16 parent_name_size;
 	u32 blob_handle;
+	u8 *blob;
 	int rc;
 
+	/*
+	 * Try to decode the provided blob as an ASN.1 blob. Assume that the
+	 * blob is in the legacy format if decoding does not end successfully.
+	 */
+	rc = tpm2_key_decode(payload, options, &blob);
+	if (rc) {
+		blob = payload->blob;
+		payload->old_format = 1;
+	} else {
+		blob_ref = blob;
+	}
+
+	if (!options->keyhandle)
+		return -EINVAL;
+
 	rc = tpm_try_get_ops(chip);
 	if (rc)
 		return rc;
 
-	rc = tpm2_load_cmd(chip, payload, options, &blob_handle);
+	rc = tpm2_read_public(chip, options->keyhandle, parent_name);
+	if (rc < 0)
+		goto out;
+
+	parent_name_size = rc;
+
+	rc = tpm2_load_cmd(chip, payload, options, parent_name,
+			   parent_name_size, blob, &blob_handle);
 	if (rc)
 		goto out;
 
-	rc = tpm2_unseal_cmd(chip, payload, options, blob_handle);
+	rc = tpm2_unseal_cmd(chip, payload, options, parent_name,
+			     parent_name_size, blob_handle);
+
 	tpm2_flush_context(chip, blob_handle);
 
 out:
-- 
2.52.0

[PATCH v2 2/2] KEYS: trusted: Store parent's name to the encoded keys

[Jarkko Sakkinen]

Extend TPMKey ASN.1 speciication [1] with an optional 'parentName'
attribute containing TPM name of the parent key (in other words, TPMT_HA
blob).

The life-cycle for trusted keys will now proceed as follows:

1. Encode parent's name to the 'paretName' during tpm2_key_encode().
2. During tpm2_unseal_trusted, read parent's name from 'parentName'. When
   the attribute is not available, fallback on doing tpm2_read_public().

In other words, in the common (i.e., not loading a legacy key blob),
tpm2_read_public() will now only happen at the time when a key is first
created.

[1] https://www.hansenpartnership.com/draft-bottomley-tpm2-keys.txt

Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
---
v2:
- A new patch.
---
 security/keys/trusted-keys/tpm2key.asn1   | 17 +++-
 security/keys/trusted-keys/trusted_tpm2.c | 97 ++++++++++++++++-------
 2 files changed, 84 insertions(+), 30 deletions(-)

diff --git a/security/keys/trusted-keys/tpm2key.asn1 b/security/keys/trusted-keys/tpm2key.asn1
index f57f869ad600..080f0e399982 100644
--- a/security/keys/trusted-keys/tpm2key.asn1
+++ b/security/keys/trusted-keys/tpm2key.asn1
@@ -1,11 +1,26 @@
 ---
 --- ASN.1 for TPM 2.0 keys
 ---
+TPMPolicy ::= SEQUENCE {
+	commandCode	[0] EXPLICIT INTEGER,
+	commandPolicy	[1] EXPLICIT OCTET STRING
+}
+
+TPMAuthPolicy ::= SEQUENCE {
+	name		[0] EXPLICIT UTF8String OPTIONAL,
+	policy		[1] EXPLICIT SEQUENCE OF TPMPolicy
+}
 
 TPMKey ::= SEQUENCE {
 	type		OBJECT IDENTIFIER ({tpm2_key_type}),
 	emptyAuth	[0] EXPLICIT BOOLEAN OPTIONAL,
+	policy		[1] EXPLICIT SEQUENCE OF TPMPolicy OPTIONAL,
+	secret		[2] EXPLICIT OCTET STRING OPTIONAL,
+	authPolicy	[3] EXPLICIT SEQUENCE OF TPMAuthPolicy OPTIONAL,
+	description	[4] EXPLICIT UTF8String OPTIONAL,
+	rsaParent	[5] EXPLICIT BOOLEAN OPTIONAL,
+	parentName	[6] EXPLICIT OCTET STRING ({tpm2_key_parent_name}),
 	parent		INTEGER ({tpm2_key_parent}),
 	pubkey		OCTET STRING ({tpm2_key_pub}),
 	privkey		OCTET STRING ({tpm2_key_priv})
-	}
+}
diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c
index 88bafbcc011a..3608dc9f7fa4 100644
--- a/security/keys/trusted-keys/trusted_tpm2.c
+++ b/security/keys/trusted-keys/trusted_tpm2.c
@@ -20,16 +20,26 @@
 
 static u32 tpm2key_oid[] = { 2, 23, 133, 10, 1, 5 };
 
+enum tpm_key_tag {
+	TPM_KEY_TAG_EMPTY_AUTH	= 0,
+	TPM_KEY_TAG_POLICY	= 1,
+	TPM_KEY_TAG_SECRET	= 2,
+	TPM_KEY_TAG_AUTH_POLICY	= 3,
+	TPM_KEY_TAG_DESCRIPTION = 4,
+	TPM_KEY_TAG_RSA_PARENT	= 5,
+	TPM_KEY_TAG_PARENT_NAME	= 6,
+};
+
 static int tpm2_key_encode(struct trusted_key_payload *payload,
 			   struct trusted_key_options *options,
-			   u8 *src, u32 len)
+			   u8 *src, u32 len, u8 *parent_name,
+			   u16 parent_name_size)
 {
 	const int SCRATCH_SIZE = PAGE_SIZE;
-	u8 *scratch = kmalloc(SCRATCH_SIZE, GFP_KERNEL);
-	u8 *work = scratch, *work1;
-	u8 *end_work = scratch + SCRATCH_SIZE;
-	u8 *priv, *pub;
+	u8 *end_work, *name_end;
 	u16 priv_len, pub_len;
+	u8 *work, *work1;
+	u8 *priv, *pub;
 	int ret;
 
 	priv_len = get_unaligned_be16(src) + 2;
@@ -40,23 +50,41 @@ static int tpm2_key_encode(struct trusted_key_payload *payload,
 	pub_len = get_unaligned_be16(src) + 2;
 	pub = src;
 
+	u8 *scratch __free(kfree) = kmalloc(SCRATCH_SIZE, GFP_KERNEL);
 	if (!scratch)
 		return -ENOMEM;
 
+	work = scratch;
+	end_work = scratch + SCRATCH_SIZE;
+
 	work = asn1_encode_oid(work, end_work, tpm2key_oid,
 			       asn1_oid_len(tpm2key_oid));
 
 	if (options->blobauth_len == 0) {
-		unsigned char bool[3], *w = bool;
-		/* tag 0 is emptyAuth */
-		w = asn1_encode_boolean(w, w + sizeof(bool), true);
-		if (WARN(IS_ERR(w), "BUG: Boolean failed to encode")) {
-			ret = PTR_ERR(w);
-			goto err;
+		u8 *bool_end;
+		u8 bool[3];
+
+		bool_end = asn1_encode_boolean(&bool[0], &bool[sizeof(bool)],
+					       true);
+		if (IS_ERR(bool_end)) {
+			pr_err("BUG: Boolean failed to encode\n");
+			return PTR_ERR(bool_end);
 		}
-		work = asn1_encode_tag(work, end_work, 0, bool, w - bool);
+
+		work = asn1_encode_tag(work, end_work, TPM_KEY_TAG_EMPTY_AUTH,
+				       bool, bool_end - bool);
 	}
 
+	u8 *name_encoded __free(kfree) = kmalloc(SCRATCH_SIZE, GFP_KERNEL);
+	if (!name_encoded)
+		return -ENOMEM;
+
+	name_end = asn1_encode_octet_string(&name_encoded[0],
+					    &name_encoded[SCRATCH_SIZE],
+					    parent_name, parent_name_size);
+	work = asn1_encode_tag(work, end_work, TPM_KEY_TAG_PARENT_NAME,
+			       name_encoded, name_end - name_encoded);
+
 	/*
 	 * Assume both octet strings will encode to a 2 byte definite length
 	 *
@@ -65,8 +93,7 @@ static int tpm2_key_encode(struct trusted_key_payload *payload,
 	 */
 	if (WARN(work - scratch + pub_len + priv_len + 14 > SCRATCH_SIZE,
 		 "BUG: scratch buffer is too small")) {
-		ret = -EINVAL;
-		goto err;
+		return -EINVAL;
 	}
 
 	work = asn1_encode_integer(work, end_work, options->keyhandle);
@@ -79,15 +106,10 @@ static int tpm2_key_encode(struct trusted_key_payload *payload,
 	if (IS_ERR(work1)) {
 		ret = PTR_ERR(work1);
 		pr_err("BUG: ASN.1 encoder failed with %d\n", ret);
-		goto err;
+		return ret;
 	}
 
-	kfree(scratch);
 	return work1 - payload->blob;
-
-err:
-	kfree(scratch);
-	return ret;
 }
 
 struct tpm2_key_context {
@@ -96,11 +118,13 @@ struct tpm2_key_context {
 	u32 pub_len;
 	const u8 *priv;
 	u32 priv_len;
+	const u8 *name;
+	u32 name_len;
 };
 
 static int tpm2_key_decode(struct trusted_key_payload *payload,
 			   struct trusted_key_options *options,
-			   u8 **buf)
+			   u8 **buf, u8 *parent_name, u16 *parent_name_size)
 {
 	int ret;
 	struct tpm2_key_context ctx;
@@ -127,6 +151,8 @@ static int tpm2_key_decode(struct trusted_key_payload *payload,
 	blob += ctx.priv_len;
 
 	memcpy(blob, ctx.pub, ctx.pub_len);
+	memcpy(parent_name, ctx.name, ctx.name_len);
+	*parent_name_size = ctx.name_len;
 
 	return 0;
 }
@@ -190,6 +216,16 @@ int tpm2_key_priv(void *context, size_t hdrlen,
 	return 0;
 }
 
+int tpm2_key_parent_name(void *context, size_t hdrlen, unsigned char tag,
+			 const void *value, size_t vlen)
+{
+	struct tpm2_key_context *ctx = context;
+
+	ctx->name = value;
+	ctx->name_len = vlen;
+
+	return 0;
+}
 /**
  * tpm2_buf_append_auth() - append TPMS_AUTH_COMMAND to the buffer.
  *
@@ -347,7 +383,8 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
 		goto out;
 	}
 
-	blob_len = tpm2_key_encode(payload, options, &buf.data[offset], blob_len);
+	blob_len = tpm2_key_encode(payload, options, &buf.data[offset],
+				   blob_len, parent_name, parent_name_size);
 	if (blob_len < 0)
 		rc = blob_len;
 
@@ -602,7 +639,7 @@ int tpm2_unseal_trusted(struct tpm_chip *chip,
 	 * Try to decode the provided blob as an ASN.1 blob. Assume that the
 	 * blob is in the legacy format if decoding does not end successfully.
 	 */
-	rc = tpm2_key_decode(payload, options, &blob);
+	rc = tpm2_key_decode(payload, options, &blob, &parent_name[0], &parent_name_size);
 	if (rc) {
 		blob = payload->blob;
 		payload->old_format = 1;
@@ -613,16 +650,18 @@ int tpm2_unseal_trusted(struct tpm_chip *chip,
 	if (!options->keyhandle)
 		return -EINVAL;
 
+	if (!parent_name_size) {
+		rc = tpm2_read_public(chip, options->keyhandle, parent_name);
+		if (rc < 0)
+			goto out;
+
+		parent_name_size = rc;
+	}
+
 	rc = tpm_try_get_ops(chip);
 	if (rc)
 		return rc;
 
-	rc = tpm2_read_public(chip, options->keyhandle, parent_name);
-	if (rc < 0)
-		goto out;
-
-	parent_name_size = rc;
-
 	rc = tpm2_load_cmd(chip, payload, options, parent_name,
 			   parent_name_size, blob, &blob_handle);
 	if (rc)
-- 
2.52.0

Re: [PATCH v2 2/2] KEYS: trusted: Store parent's name to the encoded keys

[Jarkko Sakkinen]

On Fri, Dec 05, 2025 at 05:02:05AM +0200, Jarkko Sakkinen wrote:
> Extend TPMKey ASN.1 speciication [1] with an optional 'parentName'
> attribute containing TPM name of the parent key (in other words, TPMT_HA
> blob).
> 
> The life-cycle for trusted keys will now proceed as follows:
> 
> 1. Encode parent's name to the 'paretName' during tpm2_key_encode().
> 2. During tpm2_unseal_trusted, read parent's name from 'parentName'. When
>    the attribute is not available, fallback on doing tpm2_read_public().
> 
> In other words, in the common (i.e., not loading a legacy key blob),
> tpm2_read_public() will now only happen at the time when a key is first
> created.
> 
> [1] https://www.hansenpartnership.com/draft-bottomley-tpm2-keys.txt
> 
> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
> ---
> v2:
> - A new patch.
> ---
>  security/keys/trusted-keys/tpm2key.asn1   | 17 +++-
>  security/keys/trusted-keys/trusted_tpm2.c | 97 ++++++++++++++++-------
>  2 files changed, 84 insertions(+), 30 deletions(-)
> 
> diff --git a/security/keys/trusted-keys/tpm2key.asn1 b/security/keys/trusted-keys/tpm2key.asn1
> index f57f869ad600..080f0e399982 100644
> --- a/security/keys/trusted-keys/tpm2key.asn1
> +++ b/security/keys/trusted-keys/tpm2key.asn1
> @@ -1,11 +1,26 @@
>  ---
>  --- ASN.1 for TPM 2.0 keys
>  ---
> +TPMPolicy ::= SEQUENCE {
> +	commandCode	[0] EXPLICIT INTEGER,
> +	commandPolicy	[1] EXPLICIT OCTET STRING
> +}
> +
> +TPMAuthPolicy ::= SEQUENCE {
> +	name		[0] EXPLICIT UTF8String OPTIONAL,
> +	policy		[1] EXPLICIT SEQUENCE OF TPMPolicy
> +}
>  
>  TPMKey ::= SEQUENCE {
>  	type		OBJECT IDENTIFIER ({tpm2_key_type}),
>  	emptyAuth	[0] EXPLICIT BOOLEAN OPTIONAL,
> +	policy		[1] EXPLICIT SEQUENCE OF TPMPolicy OPTIONAL,
> +	secret		[2] EXPLICIT OCTET STRING OPTIONAL,
> +	authPolicy	[3] EXPLICIT SEQUENCE OF TPMAuthPolicy OPTIONAL,
> +	description	[4] EXPLICIT UTF8String OPTIONAL,
> +	rsaParent	[5] EXPLICIT BOOLEAN OPTIONAL,
> +	parentName	[6] EXPLICIT OCTET STRING ({tpm2_key_parent_name}),
>  	parent		INTEGER ({tpm2_key_parent}),
>  	pubkey		OCTET STRING ({tpm2_key_pub}),
>  	privkey		OCTET STRING ({tpm2_key_priv})
> -	}
> +}
> diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c
> index 88bafbcc011a..3608dc9f7fa4 100644
> --- a/security/keys/trusted-keys/trusted_tpm2.c
> +++ b/security/keys/trusted-keys/trusted_tpm2.c
> @@ -20,16 +20,26 @@
>  
>  static u32 tpm2key_oid[] = { 2, 23, 133, 10, 1, 5 };
>  
> +enum tpm_key_tag {
> +	TPM_KEY_TAG_EMPTY_AUTH	= 0,
> +	TPM_KEY_TAG_POLICY	= 1,
> +	TPM_KEY_TAG_SECRET	= 2,
> +	TPM_KEY_TAG_AUTH_POLICY	= 3,
> +	TPM_KEY_TAG_DESCRIPTION = 4,
> +	TPM_KEY_TAG_RSA_PARENT	= 5,
> +	TPM_KEY_TAG_PARENT_NAME	= 6,
> +};
> +
>  static int tpm2_key_encode(struct trusted_key_payload *payload,
>  			   struct trusted_key_options *options,
> -			   u8 *src, u32 len)
> +			   u8 *src, u32 len, u8 *parent_name,
> +			   u16 parent_name_size)
>  {
>  	const int SCRATCH_SIZE = PAGE_SIZE;
> -	u8 *scratch = kmalloc(SCRATCH_SIZE, GFP_KERNEL);
> -	u8 *work = scratch, *work1;
> -	u8 *end_work = scratch + SCRATCH_SIZE;
> -	u8 *priv, *pub;
> +	u8 *end_work, *name_end;
>  	u16 priv_len, pub_len;
> +	u8 *work, *work1;
> +	u8 *priv, *pub;
>  	int ret;
>  
>  	priv_len = get_unaligned_be16(src) + 2;
> @@ -40,23 +50,41 @@ static int tpm2_key_encode(struct trusted_key_payload *payload,
>  	pub_len = get_unaligned_be16(src) + 2;
>  	pub = src;
>  
> +	u8 *scratch __free(kfree) = kmalloc(SCRATCH_SIZE, GFP_KERNEL);
>  	if (!scratch)
>  		return -ENOMEM;
>  
> +	work = scratch;
> +	end_work = scratch + SCRATCH_SIZE;
> +
>  	work = asn1_encode_oid(work, end_work, tpm2key_oid,
>  			       asn1_oid_len(tpm2key_oid));
>  
>  	if (options->blobauth_len == 0) {
> -		unsigned char bool[3], *w = bool;
> -		/* tag 0 is emptyAuth */
> -		w = asn1_encode_boolean(w, w + sizeof(bool), true);
> -		if (WARN(IS_ERR(w), "BUG: Boolean failed to encode")) {
> -			ret = PTR_ERR(w);
> -			goto err;
> +		u8 *bool_end;
> +		u8 bool[3];
> +
> +		bool_end = asn1_encode_boolean(&bool[0], &bool[sizeof(bool)],
> +					       true);
> +		if (IS_ERR(bool_end)) {
> +			pr_err("BUG: Boolean failed to encode\n");
> +			return PTR_ERR(bool_end);
>  		}
> -		work = asn1_encode_tag(work, end_work, 0, bool, w - bool);
> +
> +		work = asn1_encode_tag(work, end_work, TPM_KEY_TAG_EMPTY_AUTH,
> +				       bool, bool_end - bool);
>  	}
>  
> +	u8 *name_encoded __free(kfree) = kmalloc(SCRATCH_SIZE, GFP_KERNEL);
> +	if (!name_encoded)
> +		return -ENOMEM;
> +
> +	name_end = asn1_encode_octet_string(&name_encoded[0],
> +					    &name_encoded[SCRATCH_SIZE],
> +					    parent_name, parent_name_size);
> +	work = asn1_encode_tag(work, end_work, TPM_KEY_TAG_PARENT_NAME,
> +			       name_encoded, name_end - name_encoded);
> +
>  	/*
>  	 * Assume both octet strings will encode to a 2 byte definite length
>  	 *
> @@ -65,8 +93,7 @@ static int tpm2_key_encode(struct trusted_key_payload *payload,
>  	 */
>  	if (WARN(work - scratch + pub_len + priv_len + 14 > SCRATCH_SIZE,
>  		 "BUG: scratch buffer is too small")) {
> -		ret = -EINVAL;
> -		goto err;
> +		return -EINVAL;
>  	}
>  
>  	work = asn1_encode_integer(work, end_work, options->keyhandle);
> @@ -79,15 +106,10 @@ static int tpm2_key_encode(struct trusted_key_payload *payload,
>  	if (IS_ERR(work1)) {
>  		ret = PTR_ERR(work1);
>  		pr_err("BUG: ASN.1 encoder failed with %d\n", ret);
> -		goto err;
> +		return ret;
>  	}
>  
> -	kfree(scratch);
>  	return work1 - payload->blob;
> -
> -err:
> -	kfree(scratch);
> -	return ret;
>  }
>  
>  struct tpm2_key_context {
> @@ -96,11 +118,13 @@ struct tpm2_key_context {
>  	u32 pub_len;
>  	const u8 *priv;
>  	u32 priv_len;
> +	const u8 *name;
> +	u32 name_len;
>  };
>  
>  static int tpm2_key_decode(struct trusted_key_payload *payload,
>  			   struct trusted_key_options *options,
> -			   u8 **buf)
> +			   u8 **buf, u8 *parent_name, u16 *parent_name_size)
>  {
>  	int ret;
>  	struct tpm2_key_context ctx;
> @@ -127,6 +151,8 @@ static int tpm2_key_decode(struct trusted_key_payload *payload,
>  	blob += ctx.priv_len;
>  
>  	memcpy(blob, ctx.pub, ctx.pub_len);
> +	memcpy(parent_name, ctx.name, ctx.name_len);
> +	*parent_name_size = ctx.name_len;
>  
>  	return 0;
>  }
> @@ -190,6 +216,16 @@ int tpm2_key_priv(void *context, size_t hdrlen,
>  	return 0;
>  }
>  
> +int tpm2_key_parent_name(void *context, size_t hdrlen, unsigned char tag,
> +			 const void *value, size_t vlen)
> +{
> +	struct tpm2_key_context *ctx = context;
> +
> +	ctx->name = value;
> +	ctx->name_len = vlen;
> +
> +	return 0;
> +}
>  /**
>   * tpm2_buf_append_auth() - append TPMS_AUTH_COMMAND to the buffer.
>   *
> @@ -347,7 +383,8 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
>  		goto out;
>  	}
>  
> -	blob_len = tpm2_key_encode(payload, options, &buf.data[offset], blob_len);
> +	blob_len = tpm2_key_encode(payload, options, &buf.data[offset],
> +				   blob_len, parent_name, parent_name_size);
>  	if (blob_len < 0)
>  		rc = blob_len;
>  
> @@ -602,7 +639,7 @@ int tpm2_unseal_trusted(struct tpm_chip *chip,
>  	 * Try to decode the provided blob as an ASN.1 blob. Assume that the
>  	 * blob is in the legacy format if decoding does not end successfully.
>  	 */
> -	rc = tpm2_key_decode(payload, options, &blob);
> +	rc = tpm2_key_decode(payload, options, &blob, &parent_name[0], &parent_name_size);
>  	if (rc) {
>  		blob = payload->blob;
>  		payload->old_format = 1;
> @@ -613,16 +650,18 @@ int tpm2_unseal_trusted(struct tpm_chip *chip,
>  	if (!options->keyhandle)
>  		return -EINVAL;
>  
> +	if (!parent_name_size) {
> +		rc = tpm2_read_public(chip, options->keyhandle, parent_name);
> +		if (rc < 0)
> +			goto out;
> +
> +		parent_name_size = rc;
> +	}
> +
>  	rc = tpm_try_get_ops(chip);
>  	if (rc)
>  		return rc;
>  
> -	rc = tpm2_read_public(chip, options->keyhandle, parent_name);
> -	if (rc < 0)
> -		goto out;
> -
> -	parent_name_size = rc;
> -

Relocating this was entirely unintentional. I'll relocate it back to its
original position in the next revision of this patch set.

>  	rc = tpm2_load_cmd(chip, payload, options, parent_name,
>  			   parent_name_size, blob, &blob_handle);
>  	if (rc)
> -- 
> 2.52.0
> 

BR, Jarkko

Re: [PATCH v2 2/2] KEYS: trusted: Store parent's name to the encoded keys

[Jarkko Sakkinen]

On Fri, Dec 05, 2025 at 05:02:05AM +0200, Jarkko Sakkinen wrote:
> Extend TPMKey ASN.1 speciication [1] with an optional 'parentName'
> attribute containing TPM name of the parent key (in other words, TPMT_HA
> blob).
> 
> The life-cycle for trusted keys will now proceed as follows:
> 
> 1. Encode parent's name to the 'paretName' during tpm2_key_encode().
> 2. During tpm2_unseal_trusted, read parent's name from 'parentName'. When
>    the attribute is not available, fallback on doing tpm2_read_public().
> 
> In other words, in the common (i.e., not loading a legacy key blob),
> tpm2_read_public() will now only happen at the time when a key is first
> created.
> 
> [1] https://www.hansenpartnership.com/draft-bottomley-tpm2-keys.txt
> 
> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
> ---
> v2:
> - A new patch.
> ---
>  security/keys/trusted-keys/tpm2key.asn1   | 17 +++-
>  security/keys/trusted-keys/trusted_tpm2.c | 97 ++++++++++++++++-------
>  2 files changed, 84 insertions(+), 30 deletions(-)
> 
> diff --git a/security/keys/trusted-keys/tpm2key.asn1 b/security/keys/trusted-keys/tpm2key.asn1
> index f57f869ad600..080f0e399982 100644
> --- a/security/keys/trusted-keys/tpm2key.asn1
> +++ b/security/keys/trusted-keys/tpm2key.asn1
> @@ -1,11 +1,26 @@
>  ---
>  --- ASN.1 for TPM 2.0 keys
>  ---
> +TPMPolicy ::= SEQUENCE {
> +	commandCode	[0] EXPLICIT INTEGER,
> +	commandPolicy	[1] EXPLICIT OCTET STRING
> +}
> +
> +TPMAuthPolicy ::= SEQUENCE {
> +	name		[0] EXPLICIT UTF8String OPTIONAL,
> +	policy		[1] EXPLICIT SEQUENCE OF TPMPolicy
> +}
>  
>  TPMKey ::= SEQUENCE {
>  	type		OBJECT IDENTIFIER ({tpm2_key_type}),
>  	emptyAuth	[0] EXPLICIT BOOLEAN OPTIONAL,
> +	policy		[1] EXPLICIT SEQUENCE OF TPMPolicy OPTIONAL,
> +	secret		[2] EXPLICIT OCTET STRING OPTIONAL,
> +	authPolicy	[3] EXPLICIT SEQUENCE OF TPMAuthPolicy OPTIONAL,
> +	description	[4] EXPLICIT UTF8String OPTIONAL,
> +	rsaParent	[5] EXPLICIT BOOLEAN OPTIONAL,
> +	parentName	[6] EXPLICIT OCTET STRING ({tpm2_key_parent_name}),

Another nit. Should probably be instead:

	parentName	[6] EXPLICIT OCTET STRING OPTIONAL ({tpm2_key_parent_name}),

>  	parent		INTEGER ({tpm2_key_parent}),
>  	pubkey		OCTET STRING ({tpm2_key_pub}),
>  	privkey		OCTET STRING ({tpm2_key_priv})
> -	}
> +}
> diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c
> index 88bafbcc011a..3608dc9f7fa4 100644
> --- a/security/keys/trusted-keys/trusted_tpm2.c
> +++ b/security/keys/trusted-keys/trusted_tpm2.c
> @@ -20,16 +20,26 @@
>  
>  static u32 tpm2key_oid[] = { 2, 23, 133, 10, 1, 5 };
>  
> +enum tpm_key_tag {
> +	TPM_KEY_TAG_EMPTY_AUTH	= 0,
> +	TPM_KEY_TAG_POLICY	= 1,
> +	TPM_KEY_TAG_SECRET	= 2,
> +	TPM_KEY_TAG_AUTH_POLICY	= 3,
> +	TPM_KEY_TAG_DESCRIPTION = 4,
> +	TPM_KEY_TAG_RSA_PARENT	= 5,
> +	TPM_KEY_TAG_PARENT_NAME	= 6,
> +};
> +
>  static int tpm2_key_encode(struct trusted_key_payload *payload,
>  			   struct trusted_key_options *options,
> -			   u8 *src, u32 len)
> +			   u8 *src, u32 len, u8 *parent_name,
> +			   u16 parent_name_size)
>  {
>  	const int SCRATCH_SIZE = PAGE_SIZE;
> -	u8 *scratch = kmalloc(SCRATCH_SIZE, GFP_KERNEL);
> -	u8 *work = scratch, *work1;
> -	u8 *end_work = scratch + SCRATCH_SIZE;
> -	u8 *priv, *pub;
> +	u8 *end_work, *name_end;
>  	u16 priv_len, pub_len;
> +	u8 *work, *work1;
> +	u8 *priv, *pub;
>  	int ret;
>  
>  	priv_len = get_unaligned_be16(src) + 2;
> @@ -40,23 +50,41 @@ static int tpm2_key_encode(struct trusted_key_payload *payload,
>  	pub_len = get_unaligned_be16(src) + 2;
>  	pub = src;
>  
> +	u8 *scratch __free(kfree) = kmalloc(SCRATCH_SIZE, GFP_KERNEL);
>  	if (!scratch)
>  		return -ENOMEM;
>  
> +	work = scratch;
> +	end_work = scratch + SCRATCH_SIZE;
> +
>  	work = asn1_encode_oid(work, end_work, tpm2key_oid,
>  			       asn1_oid_len(tpm2key_oid));
>  
>  	if (options->blobauth_len == 0) {
> -		unsigned char bool[3], *w = bool;
> -		/* tag 0 is emptyAuth */
> -		w = asn1_encode_boolean(w, w + sizeof(bool), true);
> -		if (WARN(IS_ERR(w), "BUG: Boolean failed to encode")) {
> -			ret = PTR_ERR(w);
> -			goto err;
> +		u8 *bool_end;
> +		u8 bool[3];
> +
> +		bool_end = asn1_encode_boolean(&bool[0], &bool[sizeof(bool)],
> +					       true);
> +		if (IS_ERR(bool_end)) {
> +			pr_err("BUG: Boolean failed to encode\n");
> +			return PTR_ERR(bool_end);
>  		}
> -		work = asn1_encode_tag(work, end_work, 0, bool, w - bool);
> +
> +		work = asn1_encode_tag(work, end_work, TPM_KEY_TAG_EMPTY_AUTH,
> +				       bool, bool_end - bool);
>  	}
>  
> +	u8 *name_encoded __free(kfree) = kmalloc(SCRATCH_SIZE, GFP_KERNEL);
> +	if (!name_encoded)
> +		return -ENOMEM;
> +
> +	name_end = asn1_encode_octet_string(&name_encoded[0],
> +					    &name_encoded[SCRATCH_SIZE],
> +					    parent_name, parent_name_size);
> +	work = asn1_encode_tag(work, end_work, TPM_KEY_TAG_PARENT_NAME,
> +			       name_encoded, name_end - name_encoded);
> +
>  	/*
>  	 * Assume both octet strings will encode to a 2 byte definite length
>  	 *
> @@ -65,8 +93,7 @@ static int tpm2_key_encode(struct trusted_key_payload *payload,
>  	 */
>  	if (WARN(work - scratch + pub_len + priv_len + 14 > SCRATCH_SIZE,
>  		 "BUG: scratch buffer is too small")) {
> -		ret = -EINVAL;
> -		goto err;
> +		return -EINVAL;
>  	}
>  
>  	work = asn1_encode_integer(work, end_work, options->keyhandle);
> @@ -79,15 +106,10 @@ static int tpm2_key_encode(struct trusted_key_payload *payload,
>  	if (IS_ERR(work1)) {
>  		ret = PTR_ERR(work1);
>  		pr_err("BUG: ASN.1 encoder failed with %d\n", ret);
> -		goto err;
> +		return ret;
>  	}
>  
> -	kfree(scratch);
>  	return work1 - payload->blob;
> -
> -err:
> -	kfree(scratch);
> -	return ret;
>  }
>  
>  struct tpm2_key_context {
> @@ -96,11 +118,13 @@ struct tpm2_key_context {
>  	u32 pub_len;
>  	const u8 *priv;
>  	u32 priv_len;
> +	const u8 *name;
> +	u32 name_len;
>  };
>  
>  static int tpm2_key_decode(struct trusted_key_payload *payload,
>  			   struct trusted_key_options *options,
> -			   u8 **buf)
> +			   u8 **buf, u8 *parent_name, u16 *parent_name_size)
>  {
>  	int ret;
>  	struct tpm2_key_context ctx;
> @@ -127,6 +151,8 @@ static int tpm2_key_decode(struct trusted_key_payload *payload,
>  	blob += ctx.priv_len;
>  
>  	memcpy(blob, ctx.pub, ctx.pub_len);
> +	memcpy(parent_name, ctx.name, ctx.name_len);
> +	*parent_name_size = ctx.name_len;
>  
>  	return 0;
>  }
> @@ -190,6 +216,16 @@ int tpm2_key_priv(void *context, size_t hdrlen,
>  	return 0;
>  }
>  
> +int tpm2_key_parent_name(void *context, size_t hdrlen, unsigned char tag,
> +			 const void *value, size_t vlen)
> +{
> +	struct tpm2_key_context *ctx = context;
> +
> +	ctx->name = value;
> +	ctx->name_len = vlen;
> +
> +	return 0;
> +}
>  /**
>   * tpm2_buf_append_auth() - append TPMS_AUTH_COMMAND to the buffer.
>   *
> @@ -347,7 +383,8 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
>  		goto out;
>  	}
>  
> -	blob_len = tpm2_key_encode(payload, options, &buf.data[offset], blob_len);
> +	blob_len = tpm2_key_encode(payload, options, &buf.data[offset],
> +				   blob_len, parent_name, parent_name_size);
>  	if (blob_len < 0)
>  		rc = blob_len;
>  
> @@ -602,7 +639,7 @@ int tpm2_unseal_trusted(struct tpm_chip *chip,
>  	 * Try to decode the provided blob as an ASN.1 blob. Assume that the
>  	 * blob is in the legacy format if decoding does not end successfully.
>  	 */
> -	rc = tpm2_key_decode(payload, options, &blob);
> +	rc = tpm2_key_decode(payload, options, &blob, &parent_name[0], &parent_name_size);
>  	if (rc) {
>  		blob = payload->blob;
>  		payload->old_format = 1;
> @@ -613,16 +650,18 @@ int tpm2_unseal_trusted(struct tpm_chip *chip,
>  	if (!options->keyhandle)
>  		return -EINVAL;
>  
> +	if (!parent_name_size) {
> +		rc = tpm2_read_public(chip, options->keyhandle, parent_name);
> +		if (rc < 0)
> +			goto out;
> +
> +		parent_name_size = rc;
> +	}
> +
>  	rc = tpm_try_get_ops(chip);
>  	if (rc)
>  		return rc;
>  
> -	rc = tpm2_read_public(chip, options->keyhandle, parent_name);
> -	if (rc < 0)
> -		goto out;
> -
> -	parent_name_size = rc;
> -
>  	rc = tpm2_load_cmd(chip, payload, options, parent_name,
>  			   parent_name_size, blob, &blob_handle);
>  	if (rc)
> -- 
> 2.52.0
> 

BR, Jarkko