diff mbox series

[v6,1/4] KEYS: trusted: Add generic trusted keys framework

Message ID 1600350398-4813-2-git-send-email-sumit.garg@linaro.org
State New
Headers show
Series Introduce TEE based Trusted Keys support | expand

Commit Message

Sumit Garg Sept. 17, 2020, 1:46 p.m. UTC
Current trusted keys framework is tightly coupled to use TPM device as
an underlying implementation which makes it difficult for implementations
like Trusted Execution Environment (TEE) etc. to provide trusted keys
support in case platform doesn't posses a TPM device.

So this patch tries to add generic trusted keys framework where underlying
implementations like TPM, TEE etc. could be easily plugged-in.

Suggested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
---
 include/keys/trusted-type.h               |  42 ++++
 include/keys/trusted_tpm.h                |  17 +-
 security/keys/trusted-keys/Makefile       |   1 +
 security/keys/trusted-keys/trusted_core.c | 321 ++++++++++++++++++++++++++++
 security/keys/trusted-keys/trusted_tpm1.c | 336 +++++-------------------------
 5 files changed, 422 insertions(+), 295 deletions(-)
 create mode 100644 security/keys/trusted-keys/trusted_core.c

Comments

Jarkko Sakkinen Sept. 17, 2020, 4:21 p.m. UTC | #1
On Thu, Sep 17, 2020 at 07:16:35PM +0530, Sumit Garg wrote:
> Current trusted keys framework is tightly coupled to use TPM device as
> an underlying implementation which makes it difficult for implementations
> like Trusted Execution Environment (TEE) etc. to provide trusted keys
> support in case platform doesn't posses a TPM device.
> 
> So this patch tries to add generic trusted keys framework where underlying
> implementations like TPM, TEE etc. could be easily plugged-in.

I would rephrase this a bit:

"Add a generic trusted keys framework where underlying implementations
can be easily plugged in. Create struct trusted_key_ops to achieve this,
which contains necessary functions of a backend."

I remember asking about this approach that what if there was just a
header for trusted key functions and a compile time decision, which C
file to include instead of ops struct. I don't remember if these was a
conclusion on this or not.

E.g. lets say you have a device with TEE and TPM, should you be able
to be use both at run-time? I might play along how this works now but
somehow, in the commit message preferably, it should be conclude why
one alternative is chosen over another.

/Jarkko
Jarkko Sakkinen Sept. 17, 2020, 4:25 p.m. UTC | #2
On Thu, Sep 17, 2020 at 07:21:49PM +0300, Jarkko Sakkinen wrote:
> On Thu, Sep 17, 2020 at 07:16:35PM +0530, Sumit Garg wrote:
> > Current trusted keys framework is tightly coupled to use TPM device as
> > an underlying implementation which makes it difficult for implementations
> > like Trusted Execution Environment (TEE) etc. to provide trusted keys
> > support in case platform doesn't posses a TPM device.
> > 
> > So this patch tries to add generic trusted keys framework where underlying
> > implementations like TPM, TEE etc. could be easily plugged-in.
> 
> I would rephrase this a bit:
> 
> "Add a generic trusted keys framework where underlying implementations
> can be easily plugged in. Create struct trusted_key_ops to achieve this,
> which contains necessary functions of a backend."
> 
> I remember asking about this approach that what if there was just a
> header for trusted key functions and a compile time decision, which C
> file to include instead of ops struct. I don't remember if these was a
> conclusion on this or not.
> 
> E.g. lets say you have a device with TEE and TPM, should you be able
> to be use both at run-time? I might play along how this works now but
> somehow, in the commit message preferably, it should be conclude why
> one alternative is chosen over another.

We must somehow seal this discussion because the other changes are
based on this decision.

I don't think tail of this patch set takes a long time spin. This
is the main architectural decision.

/Jarkko
Sumit Garg Sept. 18, 2020, 7:03 a.m. UTC | #3
On Thu, 17 Sep 2020 at 21:55, Jarkko Sakkinen
<jarkko.sakkinen@linux.intel.com> wrote:
>
> On Thu, Sep 17, 2020 at 07:21:49PM +0300, Jarkko Sakkinen wrote:
> > On Thu, Sep 17, 2020 at 07:16:35PM +0530, Sumit Garg wrote:
> > > Current trusted keys framework is tightly coupled to use TPM device as
> > > an underlying implementation which makes it difficult for implementations
> > > like Trusted Execution Environment (TEE) etc. to provide trusted keys
> > > support in case platform doesn't posses a TPM device.
> > >
> > > So this patch tries to add generic trusted keys framework where underlying
> > > implementations like TPM, TEE etc. could be easily plugged-in.
> >
> > I would rephrase this a bit:
> >
> > "Add a generic trusted keys framework where underlying implementations
> > can be easily plugged in. Create struct trusted_key_ops to achieve this,
> > which contains necessary functions of a backend."
> >

Okay, will use it instead.

> > I remember asking about this approach that what if there was just a
> > header for trusted key functions and a compile time decision, which C
> > file to include instead of ops struct. I don't remember if these was a
> > conclusion on this or not.

This approach was implemented as part of v5 and we concluded here [1]
to revert back to the dynamic approach as distro vendors won't like to
make opinionated selection at compile time which could rather be
achieved dynamically based on platform capability.

[1] https://www.spinics.net/lists/keyrings/msg08161.html

> >
> > E.g. lets say you have a device with TEE and TPM, should you be able
> > to be use both at run-time? I might play along how this works now but
> > somehow, in the commit message preferably, it should be conclude why
> > one alternative is chosen over another.
>

Okay, so how about adding a kernel module parameter which can enforce
the user's preference about which trust source to use at runtime? And
we should only check availability for that trust source if preference
is provided otherwise by default we can traverse the trust sources
list.

See following change, if this approach looks sane, I can include it in
next version:

diff --git a/include/keys/trusted-type.h b/include/keys/trusted-type.h
index edd635a..a566451 100644
--- a/include/keys/trusted-type.h
+++ b/include/keys/trusted-type.h
@@ -63,6 +63,11 @@ struct trusted_key_ops {
        void (*exit)(void);
 };

+struct trusted_key_source {
+       char *name;
+       struct trusted_key_ops *ops;
+};
+
 extern struct key_type key_type_trusted;

 #define TRUSTED_DEBUG 0
diff --git a/security/keys/trusted-keys/trusted_core.c
b/security/keys/trusted-keys/trusted_core.c
index 83a6a15..74a3d80 100644
--- a/security/keys/trusted-keys/trusted_core.c
+++ b/security/keys/trusted-keys/trusted_core.c
@@ -21,12 +21,16 @@
 #include <linux/string.h>
 #include <linux/uaccess.h>

-static struct trusted_key_ops *available_trusted_key_ops[] = {
+static char *trusted_key_source;
+module_param_named(source, trusted_key_source, charp, 0);
+MODULE_PARM_DESC(source, "Select trusted keys source (tpm or tee)");
+
+static struct trusted_key_source trusted_key_sources[] = {
 #if defined(CONFIG_TCG_TPM)
-       &tpm_trusted_key_ops,
+       { "tpm", &tpm_trusted_key_ops },
 #endif
 #if defined(CONFIG_TEE)
-       &tee_trusted_key_ops,
+       { "tee", &tee_trusted_key_ops },
 #endif
 };
 static struct trusted_key_ops *trusted_key_ops;
@@ -296,8 +300,13 @@ static int __init init_trusted(void)
 {
        int i, ret = 0;

-       for (i = 0; i < sizeof(available_trusted_key_ops); i++) {
-               trusted_key_ops = available_trusted_key_ops[i];
+       for (i = 0; i < ARRAY_SIZE(trusted_key_sources); i++) {
+               if (trusted_key_source &&
+                   strncmp(trusted_key_source, trusted_key_sources[i].name,
+                           strlen(trusted_key_sources[i].name)))
+                       continue;
+
+               trusted_key_ops = trusted_key_sources[i].ops;

                ret = trusted_key_ops->init();
                if (!ret)

> We must somehow seal this discussion because the other changes are
> based on this decision.
>
> I don't think tail of this patch set takes a long time spin. This
> is the main architectural decision.

Agree.

-Sumit

>
> /Jarkko
diff mbox series

Patch

diff --git a/include/keys/trusted-type.h b/include/keys/trusted-type.h
index a94c03a..edd635a 100644
--- a/include/keys/trusted-type.h
+++ b/include/keys/trusted-type.h
@@ -40,6 +40,48 @@  struct trusted_key_options {
 	uint32_t policyhandle;
 };
 
+struct trusted_key_ops {
+	/*
+	 * flag to indicate if trusted key implementation supports migration
+	 * or not.
+	 */
+	unsigned char migratable;
+
+	/* Initialize key interface. */
+	int (*init)(void);
+
+	/* Seal a key. */
+	int (*seal)(struct trusted_key_payload *p, char *datablob);
+
+	/* Unseal a key. */
+	int (*unseal)(struct trusted_key_payload *p, char *datablob);
+
+	/* Get a randomized key. */
+	int (*get_random)(unsigned char *key, size_t key_len);
+
+	/* Exit key interface. */
+	void (*exit)(void);
+};
+
 extern struct key_type key_type_trusted;
 
+#define TRUSTED_DEBUG 0
+
+#if TRUSTED_DEBUG
+static inline void dump_payload(struct trusted_key_payload *p)
+{
+	pr_info("trusted_key: key_len %d\n", p->key_len);
+	print_hex_dump(KERN_INFO, "key ", DUMP_PREFIX_NONE,
+		       16, 1, p->key, p->key_len, 0);
+	pr_info("trusted_key: bloblen %d\n", p->blob_len);
+	print_hex_dump(KERN_INFO, "blob ", DUMP_PREFIX_NONE,
+		       16, 1, p->blob, p->blob_len, 0);
+	pr_info("trusted_key: migratable %d\n", p->migratable);
+}
+#else
+static inline void dump_payload(struct trusted_key_payload *p)
+{
+}
+#endif
+
 #endif /* _KEYS_TRUSTED_TYPE_H */
diff --git a/include/keys/trusted_tpm.h b/include/keys/trusted_tpm.h
index a56d8e1..fb3280a 100644
--- a/include/keys/trusted_tpm.h
+++ b/include/keys/trusted_tpm.h
@@ -16,6 +16,8 @@ 
 #define LOAD32N(buffer, offset)	(*(uint32_t *)&buffer[offset])
 #define LOAD16(buffer, offset)	(ntohs(*(uint16_t *)&buffer[offset]))
 
+extern struct trusted_key_ops tpm_trusted_key_ops;
+
 struct osapsess {
 	uint32_t handle;
 	unsigned char secret[SHA1_DIGEST_SIZE];
@@ -60,17 +62,6 @@  static inline void dump_options(struct trusted_key_options *o)
 		       16, 1, o->pcrinfo, o->pcrinfo_len, 0);
 }
 
-static inline void dump_payload(struct trusted_key_payload *p)
-{
-	pr_info("trusted_key: key_len %d\n", p->key_len);
-	print_hex_dump(KERN_INFO, "key ", DUMP_PREFIX_NONE,
-		       16, 1, p->key, p->key_len, 0);
-	pr_info("trusted_key: bloblen %d\n", p->blob_len);
-	print_hex_dump(KERN_INFO, "blob ", DUMP_PREFIX_NONE,
-		       16, 1, p->blob, p->blob_len, 0);
-	pr_info("trusted_key: migratable %d\n", p->migratable);
-}
-
 static inline void dump_sess(struct osapsess *s)
 {
 	print_hex_dump(KERN_INFO, "trusted-key: handle ", DUMP_PREFIX_NONE,
@@ -96,10 +87,6 @@  static inline void dump_options(struct trusted_key_options *o)
 {
 }
 
-static inline void dump_payload(struct trusted_key_payload *p)
-{
-}
-
 static inline void dump_sess(struct osapsess *s)
 {
 }
diff --git a/security/keys/trusted-keys/Makefile b/security/keys/trusted-keys/Makefile
index 7b73ceb..49e3bcf 100644
--- a/security/keys/trusted-keys/Makefile
+++ b/security/keys/trusted-keys/Makefile
@@ -4,5 +4,6 @@ 
 #
 
 obj-$(CONFIG_TRUSTED_KEYS) += trusted.o
+trusted-y += trusted_core.o
 trusted-y += trusted_tpm1.o
 trusted-y += trusted_tpm2.o
diff --git a/security/keys/trusted-keys/trusted_core.c b/security/keys/trusted-keys/trusted_core.c
new file mode 100644
index 0000000..4ae3fb4
--- /dev/null
+++ b/security/keys/trusted-keys/trusted_core.c
@@ -0,0 +1,321 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2010 IBM Corporation
+ * Copyright (c) 2019-2020, Linaro Limited
+ *
+ * See Documentation/security/keys/trusted-encrypted.rst
+ */
+
+#include <keys/user-type.h>
+#include <keys/trusted-type.h>
+#include <keys/trusted_tpm.h>
+#include <linux/capability.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/key-type.h>
+#include <linux/module.h>
+#include <linux/parser.h>
+#include <linux/rcupdate.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/uaccess.h>
+
+static struct trusted_key_ops *available_trusted_key_ops[] = {
+#if defined(CONFIG_TCG_TPM)
+	&tpm_trusted_key_ops,
+#endif
+};
+static struct trusted_key_ops *trusted_key_ops;
+
+enum {
+	Opt_err,
+	Opt_new, Opt_load, Opt_update,
+};
+
+static const match_table_t key_tokens = {
+	{Opt_new, "new"},
+	{Opt_load, "load"},
+	{Opt_update, "update"},
+	{Opt_err, NULL}
+};
+
+/*
+ * datablob_parse - parse the keyctl data and fill in the
+ *                  payload structure
+ *
+ * On success returns 0, otherwise -EINVAL.
+ */
+static int datablob_parse(char *datablob, struct trusted_key_payload *p)
+{
+	substring_t args[MAX_OPT_ARGS];
+	long keylen;
+	int ret = -EINVAL;
+	int key_cmd;
+	char *c;
+
+	/* main command */
+	c = strsep(&datablob, " \t");
+	if (!c)
+		return -EINVAL;
+	key_cmd = match_token(c, key_tokens, args);
+	switch (key_cmd) {
+	case Opt_new:
+		/* first argument is key size */
+		c = strsep(&datablob, " \t");
+		if (!c)
+			return -EINVAL;
+		ret = kstrtol(c, 10, &keylen);
+		if (ret < 0 || keylen < MIN_KEY_SIZE || keylen > MAX_KEY_SIZE)
+			return -EINVAL;
+		p->key_len = keylen;
+		ret = Opt_new;
+		break;
+	case Opt_load:
+		/* first argument is sealed blob */
+		c = strsep(&datablob, " \t");
+		if (!c)
+			return -EINVAL;
+		p->blob_len = strlen(c) / 2;
+		if (p->blob_len > MAX_BLOB_SIZE)
+			return -EINVAL;
+		ret = hex2bin(p->blob, c, p->blob_len);
+		if (ret < 0)
+			return -EINVAL;
+		ret = Opt_load;
+		break;
+	case Opt_update:
+		ret = Opt_update;
+		break;
+	case Opt_err:
+		return -EINVAL;
+	}
+	return ret;
+}
+
+static struct trusted_key_payload *trusted_payload_alloc(struct key *key)
+{
+	struct trusted_key_payload *p = NULL;
+	int ret;
+
+	ret = key_payload_reserve(key, sizeof(*p));
+	if (ret < 0)
+		return p;
+	p = kzalloc(sizeof(*p), GFP_KERNEL);
+
+	p->migratable = trusted_key_ops->migratable;
+
+	return p;
+}
+
+/*
+ * trusted_instantiate - create a new trusted key
+ *
+ * Unseal an existing trusted blob or, for a new key, get a
+ * random key, then seal and create a trusted key-type key,
+ * adding it to the specified keyring.
+ *
+ * On success, return 0. Otherwise return errno.
+ */
+static int trusted_instantiate(struct key *key,
+			       struct key_preparsed_payload *prep)
+{
+	struct trusted_key_payload *payload = NULL;
+	size_t datalen = prep->datalen;
+	char *datablob;
+	int ret = 0;
+	int key_cmd;
+	size_t key_len;
+
+	if (datalen <= 0 || datalen > 32767 || !prep->data)
+		return -EINVAL;
+
+	datablob = kmalloc(datalen + 1, GFP_KERNEL);
+	if (!datablob)
+		return -ENOMEM;
+	memcpy(datablob, prep->data, datalen);
+	datablob[datalen] = '\0';
+
+	payload = trusted_payload_alloc(key);
+	if (!payload) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	key_cmd = datablob_parse(datablob, payload);
+	if (key_cmd < 0) {
+		ret = key_cmd;
+		goto out;
+	}
+
+	dump_payload(payload);
+
+	switch (key_cmd) {
+	case Opt_load:
+		ret = trusted_key_ops->unseal(payload, datablob);
+		dump_payload(payload);
+		if (ret < 0)
+			pr_info("trusted_key: key_unseal failed (%d)\n", ret);
+		break;
+	case Opt_new:
+		key_len = payload->key_len;
+		ret = trusted_key_ops->get_random(payload->key, key_len);
+		if (ret != key_len) {
+			pr_info("trusted_key: key_create failed (%d)\n", ret);
+			goto out;
+		}
+
+		ret = trusted_key_ops->seal(payload, datablob);
+		if (ret < 0)
+			pr_info("trusted_key: key_seal failed (%d)\n", ret);
+		break;
+	default:
+		ret = -EINVAL;
+	}
+out:
+	kfree_sensitive(datablob);
+	if (!ret)
+		rcu_assign_keypointer(key, payload);
+	else
+		kfree_sensitive(payload);
+	return ret;
+}
+
+static void trusted_rcu_free(struct rcu_head *rcu)
+{
+	struct trusted_key_payload *p;
+
+	p = container_of(rcu, struct trusted_key_payload, rcu);
+	kfree_sensitive(p);
+}
+
+/*
+ * trusted_update - reseal an existing key with new PCR values
+ */
+static int trusted_update(struct key *key, struct key_preparsed_payload *prep)
+{
+	struct trusted_key_payload *p;
+	struct trusted_key_payload *new_p;
+	size_t datalen = prep->datalen;
+	char *datablob;
+	int ret = 0;
+
+	if (key_is_negative(key))
+		return -ENOKEY;
+	p = key->payload.data[0];
+	if (!p->migratable)
+		return -EPERM;
+	if (datalen <= 0 || datalen > 32767 || !prep->data)
+		return -EINVAL;
+
+	datablob = kmalloc(datalen + 1, GFP_KERNEL);
+	if (!datablob)
+		return -ENOMEM;
+
+	new_p = trusted_payload_alloc(key);
+	if (!new_p) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	memcpy(datablob, prep->data, datalen);
+	datablob[datalen] = '\0';
+	ret = datablob_parse(datablob, new_p);
+	if (ret != Opt_update) {
+		ret = -EINVAL;
+		kfree_sensitive(new_p);
+		goto out;
+	}
+
+	/* copy old key values, and reseal with new pcrs */
+	new_p->migratable = p->migratable;
+	new_p->key_len = p->key_len;
+	memcpy(new_p->key, p->key, p->key_len);
+	dump_payload(p);
+	dump_payload(new_p);
+
+	ret = trusted_key_ops->seal(new_p, datablob);
+	if (ret < 0) {
+		pr_info("trusted_key: key_seal failed (%d)\n", ret);
+		kfree_sensitive(new_p);
+		goto out;
+	}
+
+	rcu_assign_keypointer(key, new_p);
+	call_rcu(&p->rcu, trusted_rcu_free);
+out:
+	kfree_sensitive(datablob);
+	return ret;
+}
+
+/*
+ * trusted_read - copy the sealed blob data to userspace in hex.
+ * On success, return to userspace the trusted key datablob size.
+ */
+static long trusted_read(const struct key *key, char *buffer,
+			 size_t buflen)
+{
+	const struct trusted_key_payload *p;
+	char *bufp;
+	int i;
+
+	p = dereference_key_locked(key);
+	if (!p)
+		return -EINVAL;
+
+	if (buffer && buflen >= 2 * p->blob_len) {
+		bufp = buffer;
+		for (i = 0; i < p->blob_len; i++)
+			bufp = hex_byte_pack(bufp, p->blob[i]);
+	}
+	return 2 * p->blob_len;
+}
+
+/*
+ * trusted_destroy - clear and free the key's payload
+ */
+static void trusted_destroy(struct key *key)
+{
+	kfree_sensitive(key->payload.data[0]);
+}
+
+struct key_type key_type_trusted = {
+	.name = "trusted",
+	.instantiate = trusted_instantiate,
+	.update = trusted_update,
+	.destroy = trusted_destroy,
+	.describe = user_describe,
+	.read = trusted_read,
+};
+EXPORT_SYMBOL_GPL(key_type_trusted);
+
+static int __init init_trusted(void)
+{
+	int i, ret = 0;
+
+	for (i = 0; i < sizeof(available_trusted_key_ops); i++) {
+		trusted_key_ops = available_trusted_key_ops[i];
+
+		ret = trusted_key_ops->init();
+		if (!ret)
+			break;
+	}
+
+	/*
+	 * encrypted_keys.ko depends on successful load of this module even if
+	 * trusted key implementation is not found.
+	 */
+	if (ret == -ENODEV)
+		return 0;
+
+	return ret;
+}
+
+static void __exit cleanup_trusted(void)
+{
+	trusted_key_ops->exit();
+}
+
+late_initcall(init_trusted);
+module_exit(cleanup_trusted);
+
+MODULE_LICENSE("GPL");
diff --git a/security/keys/trusted-keys/trusted_tpm1.c b/security/keys/trusted-keys/trusted_tpm1.c
index b9fe02e..1c5df77 100644
--- a/security/keys/trusted-keys/trusted_tpm1.c
+++ b/security/keys/trusted-keys/trusted_tpm1.c
@@ -1,29 +1,22 @@ 
 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2010 IBM Corporation
- *
- * Author:
- * David Safford <safford@us.ibm.com>
+ * Copyright (c) 2019-2020, Linaro Limited
  *
  * See Documentation/security/keys/trusted-encrypted.rst
  */
 
 #include <crypto/hash_info.h>
-#include <linux/uaccess.h>
-#include <linux/module.h>
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/parser.h>
 #include <linux/string.h>
 #include <linux/err.h>
-#include <keys/user-type.h>
 #include <keys/trusted-type.h>
 #include <linux/key-type.h>
-#include <linux/rcupdate.h>
 #include <linux/crypto.h>
 #include <crypto/hash.h>
 #include <crypto/sha.h>
-#include <linux/capability.h>
 #include <linux/tpm.h>
 #include <linux/tpm_command.h>
 
@@ -703,7 +696,6 @@  static int key_unseal(struct trusted_key_payload *p,
 
 enum {
 	Opt_err,
-	Opt_new, Opt_load, Opt_update,
 	Opt_keyhandle, Opt_keyauth, Opt_blobauth,
 	Opt_pcrinfo, Opt_pcrlock, Opt_migratable,
 	Opt_hash,
@@ -712,9 +704,6 @@  enum {
 };
 
 static const match_table_t key_tokens = {
-	{Opt_new, "new"},
-	{Opt_load, "load"},
-	{Opt_update, "update"},
 	{Opt_keyhandle, "keyhandle=%s"},
 	{Opt_keyauth, "keyauth=%s"},
 	{Opt_blobauth, "blobauth=%s"},
@@ -841,71 +830,6 @@  static int getoptions(char *c, struct trusted_key_payload *pay,
 	return 0;
 }
 
-/*
- * datablob_parse - parse the keyctl data and fill in the
- * 		    payload and options structures
- *
- * On success returns 0, otherwise -EINVAL.
- */
-static int datablob_parse(char *datablob, struct trusted_key_payload *p,
-			  struct trusted_key_options *o)
-{
-	substring_t args[MAX_OPT_ARGS];
-	long keylen;
-	int ret = -EINVAL;
-	int key_cmd;
-	char *c;
-
-	/* main command */
-	c = strsep(&datablob, " \t");
-	if (!c)
-		return -EINVAL;
-	key_cmd = match_token(c, key_tokens, args);
-	switch (key_cmd) {
-	case Opt_new:
-		/* first argument is key size */
-		c = strsep(&datablob, " \t");
-		if (!c)
-			return -EINVAL;
-		ret = kstrtol(c, 10, &keylen);
-		if (ret < 0 || keylen < MIN_KEY_SIZE || keylen > MAX_KEY_SIZE)
-			return -EINVAL;
-		p->key_len = keylen;
-		ret = getoptions(datablob, p, o);
-		if (ret < 0)
-			return ret;
-		ret = Opt_new;
-		break;
-	case Opt_load:
-		/* first argument is sealed blob */
-		c = strsep(&datablob, " \t");
-		if (!c)
-			return -EINVAL;
-		p->blob_len = strlen(c) / 2;
-		if (p->blob_len > MAX_BLOB_SIZE)
-			return -EINVAL;
-		ret = hex2bin(p->blob, c, p->blob_len);
-		if (ret < 0)
-			return -EINVAL;
-		ret = getoptions(datablob, p, o);
-		if (ret < 0)
-			return ret;
-		ret = Opt_load;
-		break;
-	case Opt_update:
-		/* all arguments are options */
-		ret = getoptions(datablob, p, o);
-		if (ret < 0)
-			return ret;
-		ret = Opt_update;
-		break;
-	case Opt_err:
-		return -EINVAL;
-		break;
-	}
-	return ret;
-}
-
 static struct trusted_key_options *trusted_options_alloc(void)
 {
 	struct trusted_key_options *options;
@@ -926,248 +850,99 @@  static struct trusted_key_options *trusted_options_alloc(void)
 	return options;
 }
 
-static struct trusted_key_payload *trusted_payload_alloc(struct key *key)
+static int tpm_trusted_seal(struct trusted_key_payload *p, char *datablob)
 {
-	struct trusted_key_payload *p = NULL;
-	int ret;
-
-	ret = key_payload_reserve(key, sizeof *p);
-	if (ret < 0)
-		return p;
-	p = kzalloc(sizeof *p, GFP_KERNEL);
-	if (p)
-		p->migratable = 1; /* migratable by default */
-	return p;
-}
-
-/*
- * trusted_instantiate - create a new trusted key
- *
- * Unseal an existing trusted blob or, for a new key, get a
- * random key, then seal and create a trusted key-type key,
- * adding it to the specified keyring.
- *
- * On success, return 0. Otherwise return errno.
- */
-static int trusted_instantiate(struct key *key,
-			       struct key_preparsed_payload *prep)
-{
-	struct trusted_key_payload *payload = NULL;
 	struct trusted_key_options *options = NULL;
-	size_t datalen = prep->datalen;
-	char *datablob;
 	int ret = 0;
-	int key_cmd;
-	size_t key_len;
 	int tpm2;
 
 	tpm2 = tpm_is_tpm2(chip);
 	if (tpm2 < 0)
 		return tpm2;
 
-	if (datalen <= 0 || datalen > 32767 || !prep->data)
-		return -EINVAL;
-
-	datablob = kmalloc(datalen + 1, GFP_KERNEL);
-	if (!datablob)
-		return -ENOMEM;
-	memcpy(datablob, prep->data, datalen);
-	datablob[datalen] = '\0';
-
 	options = trusted_options_alloc();
-	if (!options) {
-		ret = -ENOMEM;
-		goto out;
-	}
-	payload = trusted_payload_alloc(key);
-	if (!payload) {
-		ret = -ENOMEM;
-		goto out;
-	}
+	if (!options)
+		return -ENOMEM;
 
-	key_cmd = datablob_parse(datablob, payload, options);
-	if (key_cmd < 0) {
-		ret = key_cmd;
+	ret = getoptions(datablob, p, options);
+	if (ret < 0)
 		goto out;
-	}
+	dump_options(options);
 
 	if (!options->keyhandle) {
 		ret = -EINVAL;
 		goto out;
 	}
 
-	dump_payload(payload);
-	dump_options(options);
+	if (tpm2)
+		ret = tpm2_seal_trusted(chip, p, options);
+	else
+		ret = key_seal(p, options);
+	if (ret < 0) {
+		pr_info("tpm_trusted_key: key_seal failed (%d)\n", ret);
+		goto out;
+	}
 
-	switch (key_cmd) {
-	case Opt_load:
-		if (tpm2)
-			ret = tpm2_unseal_trusted(chip, payload, options);
-		else
-			ret = key_unseal(payload, options);
-		dump_payload(payload);
-		dump_options(options);
-		if (ret < 0)
-			pr_info("trusted_key: key_unseal failed (%d)\n", ret);
-		break;
-	case Opt_new:
-		key_len = payload->key_len;
-		ret = tpm_get_random(chip, payload->key, key_len);
-		if (ret != key_len) {
-			pr_info("trusted_key: key_create failed (%d)\n", ret);
+	if (options->pcrlock) {
+		ret = pcrlock(options->pcrlock);
+		if (ret < 0) {
+			pr_info("tpm_trusted_key: pcrlock failed (%d)\n", ret);
 			goto out;
 		}
-		if (tpm2)
-			ret = tpm2_seal_trusted(chip, payload, options);
-		else
-			ret = key_seal(payload, options);
-		if (ret < 0)
-			pr_info("trusted_key: key_seal failed (%d)\n", ret);
-		break;
-	default:
-		ret = -EINVAL;
-		goto out;
 	}
-	if (!ret && options->pcrlock)
-		ret = pcrlock(options->pcrlock);
 out:
-	kfree_sensitive(datablob);
 	kfree_sensitive(options);
-	if (!ret)
-		rcu_assign_keypointer(key, payload);
-	else
-		kfree_sensitive(payload);
 	return ret;
 }
 
-static void trusted_rcu_free(struct rcu_head *rcu)
-{
-	struct trusted_key_payload *p;
-
-	p = container_of(rcu, struct trusted_key_payload, rcu);
-	kfree_sensitive(p);
-}
-
-/*
- * trusted_update - reseal an existing key with new PCR values
- */
-static int trusted_update(struct key *key, struct key_preparsed_payload *prep)
+static int tpm_trusted_unseal(struct trusted_key_payload *p, char *datablob)
 {
-	struct trusted_key_payload *p;
-	struct trusted_key_payload *new_p;
-	struct trusted_key_options *new_o;
-	size_t datalen = prep->datalen;
-	char *datablob;
+	struct trusted_key_options *options = NULL;
 	int ret = 0;
+	int tpm2;
 
-	if (key_is_negative(key))
-		return -ENOKEY;
-	p = key->payload.data[0];
-	if (!p->migratable)
-		return -EPERM;
-	if (datalen <= 0 || datalen > 32767 || !prep->data)
-		return -EINVAL;
+	tpm2 = tpm_is_tpm2(chip);
+	if (tpm2 < 0)
+		return tpm2;
 
-	datablob = kmalloc(datalen + 1, GFP_KERNEL);
-	if (!datablob)
+	options = trusted_options_alloc();
+	if (!options)
 		return -ENOMEM;
-	new_o = trusted_options_alloc();
-	if (!new_o) {
-		ret = -ENOMEM;
-		goto out;
-	}
-	new_p = trusted_payload_alloc(key);
-	if (!new_p) {
-		ret = -ENOMEM;
-		goto out;
-	}
 
-	memcpy(datablob, prep->data, datalen);
-	datablob[datalen] = '\0';
-	ret = datablob_parse(datablob, new_p, new_o);
-	if (ret != Opt_update) {
-		ret = -EINVAL;
-		kfree_sensitive(new_p);
+	ret = getoptions(datablob, p, options);
+	if (ret < 0)
 		goto out;
-	}
+	dump_options(options);
 
-	if (!new_o->keyhandle) {
+	if (!options->keyhandle) {
 		ret = -EINVAL;
-		kfree_sensitive(new_p);
 		goto out;
 	}
 
-	/* copy old key values, and reseal with new pcrs */
-	new_p->migratable = p->migratable;
-	new_p->key_len = p->key_len;
-	memcpy(new_p->key, p->key, p->key_len);
-	dump_payload(p);
-	dump_payload(new_p);
+	if (tpm2)
+		ret = tpm2_unseal_trusted(chip, p, options);
+	else
+		ret = key_unseal(p, options);
+	if (ret < 0)
+		pr_info("tpm_trusted_key: key_unseal failed (%d)\n", ret);
 
-	ret = key_seal(new_p, new_o);
-	if (ret < 0) {
-		pr_info("trusted_key: key_seal failed (%d)\n", ret);
-		kfree_sensitive(new_p);
-		goto out;
-	}
-	if (new_o->pcrlock) {
-		ret = pcrlock(new_o->pcrlock);
+	if (options->pcrlock) {
+		ret = pcrlock(options->pcrlock);
 		if (ret < 0) {
-			pr_info("trusted_key: pcrlock failed (%d)\n", ret);
-			kfree_sensitive(new_p);
+			pr_info("tpm_trusted_key: pcrlock failed (%d)\n", ret);
 			goto out;
 		}
 	}
-	rcu_assign_keypointer(key, new_p);
-	call_rcu(&p->rcu, trusted_rcu_free);
 out:
-	kfree_sensitive(datablob);
-	kfree_sensitive(new_o);
+	kfree_sensitive(options);
 	return ret;
 }
 
-/*
- * trusted_read - copy the sealed blob data to userspace in hex.
- * On success, return to userspace the trusted key datablob size.
- */
-static long trusted_read(const struct key *key, char *buffer,
-			 size_t buflen)
-{
-	const struct trusted_key_payload *p;
-	char *bufp;
-	int i;
-
-	p = dereference_key_locked(key);
-	if (!p)
-		return -EINVAL;
-
-	if (buffer && buflen >= 2 * p->blob_len) {
-		bufp = buffer;
-		for (i = 0; i < p->blob_len; i++)
-			bufp = hex_byte_pack(bufp, p->blob[i]);
-	}
-	return 2 * p->blob_len;
-}
-
-/*
- * trusted_destroy - clear and free the key's payload
- */
-static void trusted_destroy(struct key *key)
+static int tpm_trusted_get_random(unsigned char *key, size_t key_len)
 {
-	kfree_sensitive(key->payload.data[0]);
+	return tpm_get_random(chip, key, key_len);
 }
 
-struct key_type key_type_trusted = {
-	.name = "trusted",
-	.instantiate = trusted_instantiate,
-	.update = trusted_update,
-	.destroy = trusted_destroy,
-	.describe = user_describe,
-	.read = trusted_read,
-};
-
-EXPORT_SYMBOL_GPL(key_type_trusted);
-
 static void trusted_shash_release(void)
 {
 	if (hashalg)
@@ -1182,14 +957,14 @@  static int __init trusted_shash_alloc(void)
 
 	hmacalg = crypto_alloc_shash(hmac_alg, 0, 0);
 	if (IS_ERR(hmacalg)) {
-		pr_info("trusted_key: could not allocate crypto %s\n",
+		pr_info("tpm_trusted_key: could not allocate crypto %s\n",
 			hmac_alg);
 		return PTR_ERR(hmacalg);
 	}
 
 	hashalg = crypto_alloc_shash(hash_alg, 0, 0);
 	if (IS_ERR(hashalg)) {
-		pr_info("trusted_key: could not allocate crypto %s\n",
+		pr_info("tpm_trusted_key: could not allocate crypto %s\n",
 			hash_alg);
 		ret = PTR_ERR(hashalg);
 		goto hashalg_fail;
@@ -1217,16 +992,13 @@  static int __init init_digests(void)
 	return 0;
 }
 
-static int __init init_trusted(void)
+static int __init init_tpm_trusted(void)
 {
 	int ret;
 
-	/* encrypted_keys.ko depends on successful load of this module even if
-	 * TPM is not used.
-	 */
 	chip = tpm_default_chip();
 	if (!chip)
-		return 0;
+		return -ENODEV;
 
 	ret = init_digests();
 	if (ret < 0)
@@ -1247,7 +1019,7 @@  static int __init init_trusted(void)
 	return ret;
 }
 
-static void __exit cleanup_trusted(void)
+static void __exit exit_tpm_trusted(void)
 {
 	if (chip) {
 		put_device(&chip->dev);
@@ -1257,7 +1029,11 @@  static void __exit cleanup_trusted(void)
 	}
 }
 
-late_initcall(init_trusted);
-module_exit(cleanup_trusted);
-
-MODULE_LICENSE("GPL");
+struct trusted_key_ops tpm_trusted_key_ops = {
+	.migratable = 1, /* migratable by default */
+	.init = init_tpm_trusted,
+	.seal = tpm_trusted_seal,
+	.unseal = tpm_trusted_unseal,
+	.get_random = tpm_trusted_get_random,
+	.exit = exit_tpm_trusted,
+};