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tpm: seal/unseal for TPM 2.0

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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>
Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
This commit is contained in:
Jarkko Sakkinen 2015-05-30 08:09:04 +03:00 committed by Peter Huewe
parent fe351e8d4e
commit 954650efb7
5 changed files with 366 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

76
drivers/char/tpm/tpm-interface.c
View File

@ -665,6 +665,30 @@ int tpm_pcr_read_dev(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
return rc;
}
/**
* 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
@ -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;

15
drivers/char/tpm/tpm.h
View File

@ -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);

250
drivers/char/tpm/tpm2-cmd.c
View File

@ -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;
@ -380,6 +385,249 @@ static const struct tpm_input_header tpm2_get_tpm_pt_header = {
.ordinal = cpu_to_be32(TPM2_CC_GET_CAPABILITY)
};
/**
* 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.

2
include/keys/trusted-type.h
View File

@ -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 {

26
include/linux/tpm.h
View File

@ -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