diff mbox

[tpmdd-devel,08/10] tpm: seal/unseal for TPM 2.0

Message ID 1445020843-9382-9-git-send-email-jarkko.sakkinen@linux.intel.com
State Awaiting Upstream
Headers show

Commit Message

Jarkko Sakkinen Oct. 16, 2015, 6:40 p.m. UTC
Added tpm_trusted_seal() and tpm_trusted_unseal() API for sealing
trusted keys.

This patch implements basic sealing and unsealing functionality for
TPM 2.0:

* Seal with a parent key using a 20 byte auth value.
* Unseal with a parent key using a 20 byte auth value.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 drivers/char/tpm/tpm-interface.c |  76 ++++++++++++
 drivers/char/tpm/tpm.h           |  15 ++-
 drivers/char/tpm/tpm2-cmd.c      | 250 ++++++++++++++++++++++++++++++++++++++-
 include/keys/trusted-type.h      |   2 +-
 include/linux/tpm.h              |  26 ++++
 5 files changed, 366 insertions(+), 3 deletions(-)

Comments

Jeremiah Mahler Nov. 7, 2015, 6:58 p.m. UTC | #1
Jarkko,

On Fri, Oct 16, 2015 at 09:40:27PM +0300, Jarkko Sakkinen wrote:
> Added tpm_trusted_seal() and tpm_trusted_unseal() API for sealing
> trusted keys.
> 
> This patch implements basic sealing and unsealing functionality for
> TPM 2.0:
> 
> * Seal with a parent key using a 20 byte auth value.
> * Unseal with a parent key using a 20 byte auth value.
> 
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> ---
>  drivers/char/tpm/tpm-interface.c |  76 ++++++++++++
>  drivers/char/tpm/tpm.h           |  15 ++-
>  drivers/char/tpm/tpm2-cmd.c      | 250 ++++++++++++++++++++++++++++++++++++++-
>  include/keys/trusted-type.h      |   2 +-
>  include/linux/tpm.h              |  26 ++++
>  5 files changed, 366 insertions(+), 3 deletions(-)
> 

This patch adds a lot of code but doesn't use any of it until later
patches.  This can make using 'git bisect' more difficult because it
will point to the wrong patches.  If this were my patch series I would
combine this patch with the later ones that actually start using the
code.

[...]
Jarkko Sakkinen Nov. 7, 2015, 9:39 p.m. UTC | #2
On Sat, Nov 07, 2015 at 10:58:03AM -0800, Jeremiah Mahler wrote:
> Jarkko,
> 
> On Fri, Oct 16, 2015 at 09:40:27PM +0300, Jarkko Sakkinen wrote:
> > Added tpm_trusted_seal() and tpm_trusted_unseal() API for sealing
> > trusted keys.
> > 
> > This patch implements basic sealing and unsealing functionality for
> > TPM 2.0:
> > 
> > * Seal with a parent key using a 20 byte auth value.
> > * Unseal with a parent key using a 20 byte auth value.
> > 
> > Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> > ---
> >  drivers/char/tpm/tpm-interface.c |  76 ++++++++++++
> >  drivers/char/tpm/tpm.h           |  15 ++-
> >  drivers/char/tpm/tpm2-cmd.c      | 250 ++++++++++++++++++++++++++++++++++++++-
> >  include/keys/trusted-type.h      |   2 +-
> >  include/linux/tpm.h              |  26 ++++
> >  5 files changed, 366 insertions(+), 3 deletions(-)
> > 
> 
> This patch adds a lot of code but doesn't use any of it until later
> patches.  This can make using 'git bisect' more difficult because it
> will point to the wrong patches.  If this were my patch series I would
> combine this patch with the later ones that actually start using the
> code.
> 
> [...]

I do agree with you that it'd had been a good idea. Thanks for the
feedback.

> -- 
> - Jeremiah Mahler
> --

/Jarkko

------------------------------------------------------------------------------
diff mbox

Patch

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index e85d341..c50637d 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -666,6 +666,30 @@  int tpm_pcr_read_dev(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
 }
 
 /**
+ * tpm_is_tpm2 - is the chip a TPM2 chip?
+ * @chip_num:	tpm idx # or ANY
+ *
+ * Returns < 0 on error, and 1 or 0 on success depending whether the chip
+ * is a TPM2 chip.
+ */
+int tpm_is_tpm2(u32 chip_num)
+{
+	struct tpm_chip *chip;
+	int rc;
+
+	chip = tpm_chip_find_get(chip_num);
+	if (chip == NULL)
+		return -ENODEV;
+
+	rc = (chip->flags & TPM_CHIP_FLAG_TPM2) != 0;
+
+	tpm_chip_put(chip);
+
+	return rc;
+}
+EXPORT_SYMBOL_GPL(tpm_is_tpm2);
+
+/**
  * tpm_pcr_read - read a pcr value
  * @chip_num:	tpm idx # or ANY
  * @pcr_idx:	pcr idx to retrieve
@@ -1021,6 +1045,58 @@  int tpm_get_random(u32 chip_num, u8 *out, size_t max)
 }
 EXPORT_SYMBOL_GPL(tpm_get_random);
 
+/**
+ * tpm_seal_trusted() - seal a trusted key
+ * @chip_num: A specific chip number for the request or TPM_ANY_NUM
+ * @options: authentication values and other options
+ * @payload: the key data in clear and encrypted form
+ *
+ * Returns < 0 on error and 0 on success. At the moment, only TPM 2.0 chips
+ * are supported.
+ */
+int tpm_seal_trusted(u32 chip_num, struct trusted_key_payload *payload,
+		     struct trusted_key_options *options)
+{
+	struct tpm_chip *chip;
+	int rc;
+
+	chip = tpm_chip_find_get(chip_num);
+	if (chip == NULL || !(chip->flags & TPM_CHIP_FLAG_TPM2))
+		return -ENODEV;
+
+	rc = tpm2_seal_trusted(chip, payload, options);
+
+	tpm_chip_put(chip);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(tpm_seal_trusted);
+
+/**
+ * tpm_unseal_trusted() - unseal a trusted key
+ * @chip_num: A specific chip number for the request or TPM_ANY_NUM
+ * @options: authentication values and other options
+ * @payload: the key data in clear and encrypted form
+ *
+ * Returns < 0 on error and 0 on success. At the moment, only TPM 2.0 chips
+ * are supported.
+ */
+int tpm_unseal_trusted(u32 chip_num, struct trusted_key_payload *payload,
+		       struct trusted_key_options *options)
+{
+	struct tpm_chip *chip;
+	int rc;
+
+	chip = tpm_chip_find_get(chip_num);
+	if (chip == NULL || !(chip->flags & TPM_CHIP_FLAG_TPM2))
+		return -ENODEV;
+
+	rc = tpm2_unseal_trusted(chip, payload, options);
+
+	tpm_chip_put(chip);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(tpm_unseal_trusted);
+
 static int __init tpm_init(void)
 {
 	int rc;
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index cb46f62..a4257a3 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -90,6 +90,9 @@  enum tpm2_return_codes {
 
 enum tpm2_algorithms {
 	TPM2_ALG_SHA1		= 0x0004,
+	TPM2_ALG_KEYEDHASH	= 0x0008,
+	TPM2_ALG_SHA256		= 0x000B,
+	TPM2_ALG_NULL		= 0x0010
 };
 
 enum tpm2_command_codes {
@@ -97,6 +100,10 @@  enum tpm2_command_codes {
 	TPM2_CC_SELF_TEST	= 0x0143,
 	TPM2_CC_STARTUP		= 0x0144,
 	TPM2_CC_SHUTDOWN	= 0x0145,
+	TPM2_CC_CREATE		= 0x0153,
+	TPM2_CC_LOAD		= 0x0157,
+	TPM2_CC_UNSEAL		= 0x015E,
+	TPM2_CC_FLUSH_CONTEXT	= 0x0165,
 	TPM2_CC_GET_CAPABILITY	= 0x017A,
 	TPM2_CC_GET_RANDOM	= 0x017B,
 	TPM2_CC_PCR_READ	= 0x017E,
@@ -407,7 +414,7 @@  struct tpm_buf {
 	u8 *data;
 };
 
-static inline void tpm_buf_init(struct tpm_buf *buf, u16 tag, u32 ordinal)
+static inline int tpm_buf_init(struct tpm_buf *buf, u16 tag, u32 ordinal)
 {
 	struct tpm_input_header *head;
 
@@ -527,6 +534,12 @@  static inline void tpm_add_ppi(struct tpm_chip *chip)
 int tpm2_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf);
 int tpm2_pcr_extend(struct tpm_chip *chip, int pcr_idx, const u8 *hash);
 int tpm2_get_random(struct tpm_chip *chip, u8 *out, size_t max);
+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);
 
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 011909a..bd7039f 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -1,5 +1,5 @@ 
 /*
- * Copyright (C) 2014 Intel Corporation
+ * Copyright (C) 2014, 2015 Intel Corporation
  *
  * Authors:
  * Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
@@ -16,6 +16,11 @@ 
  */
 
 #include "tpm.h"
+#include <keys/trusted-type.h>
+
+enum tpm2_object_attributes {
+	TPM2_ATTR_USER_WITH_AUTH	= BIT(6),
+};
 
 struct tpm2_startup_in {
 	__be16	startup_type;
@@ -381,6 +386,249 @@  static const struct tpm_input_header tpm2_get_tpm_pt_header = {
 };
 
 /**
+ * Append TPMS_AUTH_COMMAND to the buffer. The buffer must be allocated with
+ * tpm_buf_alloc().
+ *
+ * @param buf: an allocated tpm_buf instance
+ * @param nonce: the session nonce, may be NULL if not used
+ * @param nonce_len: the session nonce length, may be 0 if not used
+ * @param attributes: the session attributes
+ * @param hmac: the session HMAC or password, may be NULL if not used
+ * @param 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 a trusted key
+ * @chip_num: A specific chip number for the request or TPM_ANY_NUM
+ * @options: authentication values and other options
+ * @payload: the key data in clear and encrypted form
+ *
+ * Returns < 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;
+	int rc;
+
+	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);
+
+	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);
+	tpm_buf_append(&buf, payload->key, payload->key_len);
+
+	/* public */
+	tpm_buf_append_u16(&buf, 14);
+
+	tpm_buf_append_u16(&buf, TPM2_ALG_KEYEDHASH);
+	tpm_buf_append_u16(&buf, TPM2_ALG_SHA256);
+	tpm_buf_append_u32(&buf, TPM2_ATTR_USER_WITH_AUTH);
+	tpm_buf_append_u16(&buf, 0); /* policy digest size */
+	tpm_buf_append_u16(&buf, TPM2_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.data, PAGE_SIZE, "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;
+	}
+
+	memcpy(payload->blob, &buf.data[TPM_HEADER_SIZE + 4], blob_len);
+	payload->blob_len = blob_len;
+
+out:
+	tpm_buf_destroy(&buf);
+
+	if (rc > 0)
+		rc = -EPERM;
+
+	return rc;
+}
+
+static int tpm2_load(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.data, PAGE_SIZE, "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;
+}
+
+static void tpm2_flush_context(struct tpm_chip *chip, u32 handle)
+{
+	struct tpm_buf buf;
+	int rc;
+
+	rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_FLUSH_CONTEXT);
+	if (rc) {
+		dev_warn(chip->pdev, "0x%08x was not flushed, out of memory\n",
+			 handle);
+		return;
+	}
+
+	tpm_buf_append_u32(&buf, handle);
+
+	rc = tpm_transmit_cmd(chip, buf.data, PAGE_SIZE, "flushing context");
+	if (rc)
+		dev_warn(chip->pdev, "0x%08x was not flushed, rc=%d\n", handle,
+			 rc);
+
+	tpm_buf_destroy(&buf);
+}
+
+static int tpm2_unseal(struct tpm_chip *chip,
+		       struct trusted_key_payload *payload,
+		       struct trusted_key_options *options,
+		       u32 blob_handle)
+{
+	struct tpm_buf buf;
+	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, TPM2_RS_PW,
+			     NULL /* nonce */, 0,
+			     0 /* session_attributes */,
+			     options->blobauth /* hmac */,
+			     TPM_DIGEST_SIZE);
+
+	rc = tpm_transmit_cmd(chip, buf.data, PAGE_SIZE, "unsealing");
+	if (rc > 0)
+		rc = -EPERM;
+
+	if (!rc) {
+		payload->key_len = be16_to_cpup(
+			(__be16 *) &buf.data[TPM_HEADER_SIZE + 4]);
+
+		memcpy(payload->key, &buf.data[TPM_HEADER_SIZE + 6],
+		       payload->key_len);
+	}
+
+	tpm_buf_destroy(&buf);
+	return rc;
+}
+
+/**
+ * tpm_unseal_trusted() - unseal a trusted key
+ * @chip_num: A specific chip number for the request or TPM_ANY_NUM
+ * @options: authentication values and other options
+ * @payload: the key data in clear and encrypted form
+ *
+ * Returns < 0 on error and 0 on success.
+ */
+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(chip, payload, options, &blob_handle);
+	if (rc)
+		return rc;
+
+	rc = tpm2_unseal(chip, payload, options, blob_handle);
+
+	tpm2_flush_context(chip, blob_handle);
+
+	return rc;
+}
+
+/**
  * tpm2_get_tpm_pt() - get value of a TPM_CAP_TPM_PROPERTIES type property
  * @chip:		TPM chip to use.
  * @property_id:	property ID.
diff --git a/include/keys/trusted-type.h b/include/keys/trusted-type.h
index c91651f..f91ecd9 100644
--- a/include/keys/trusted-type.h
+++ b/include/keys/trusted-type.h
@@ -16,7 +16,7 @@ 
 
 #define MIN_KEY_SIZE			32
 #define MAX_KEY_SIZE			128
-#define MAX_BLOB_SIZE			320
+#define MAX_BLOB_SIZE			512
 #define MAX_PCRINFO_SIZE		64
 
 struct trusted_key_payload {
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index 8350c53..706e63e 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -30,6 +30,8 @@ 
 #define	TPM_ANY_NUM 0xFFFF
 
 struct tpm_chip;
+struct trusted_key_payload;
+struct trusted_key_options;
 
 struct tpm_class_ops {
 	const u8 req_complete_mask;
@@ -46,11 +48,22 @@  struct tpm_class_ops {
 
 #if defined(CONFIG_TCG_TPM) || defined(CONFIG_TCG_TPM_MODULE)
 
+extern int tpm_is_tpm2(u32 chip_num);
 extern int tpm_pcr_read(u32 chip_num, int pcr_idx, u8 *res_buf);
 extern int tpm_pcr_extend(u32 chip_num, int pcr_idx, const u8 *hash);
 extern int tpm_send(u32 chip_num, void *cmd, size_t buflen);
 extern int tpm_get_random(u32 chip_num, u8 *data, size_t max);
+extern int tpm_seal_trusted(u32 chip_num,
+			    struct trusted_key_payload *payload,
+			    struct trusted_key_options *options);
+extern int tpm_unseal_trusted(u32 chip_num,
+			      struct trusted_key_payload *payload,
+			      struct trusted_key_options *options);
 #else
+static inline int tpm_is_tpm2(u32 chip_num)
+{
+	return -ENODEV;
+}
 static inline int tpm_pcr_read(u32 chip_num, int pcr_idx, u8 *res_buf) {
 	return -ENODEV;
 }
@@ -63,5 +76,18 @@  static inline int tpm_send(u32 chip_num, void *cmd, size_t buflen) {
 static inline int tpm_get_random(u32 chip_num, u8 *data, size_t max) {
 	return -ENODEV;
 }
+
+static inline int tpm_seal_trusted(u32 chip_num,
+				   struct trusted_key_payload *payload,
+				   struct trusted_key_options *options)
+{
+	return -ENODEV;
+}
+static inline int tpm_unseal_trusted(u32 chip_num,
+				     struct trusted_key_payload *payload,
+				     struct trusted_key_options *options)
+{
+	return -ENODEV;
+}
 #endif
 #endif