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u-boot/lib/tpm.c
mario.six@gdsys.cc 0f4b2ba176 tpm: Add function to load keys via their parent's SHA1 hash 
If we want to load a key into a TPM, we need to know the designated parent
key's handle, so that the TPM is able to insert the key at the correct place in
the key hierarchy.

However, if we want to load a key whose designated parent key we also
previously loaded ourselves, we first need to memorize this parent key's handle
(since the handles for the key are chosen at random when they are inserted into
the TPM). If we are, however, unable to do so, for example if the parent key is
loaded into the TPM during production, and its child key during the actual
boot, we must find a different mechanism to identify the parent key.

To solve this problem, we add a function that allows U-Boot to load a key into
the TPM using their designated parent key's SHA1 hash, and the corresponding
auth data.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Reviewed-by: Simon Glass <sjg@chromium.org>
2017-03-26 13:22:58 -06:00

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/*
* Copyright (c) 2013 The Chromium OS Authors.
* Coypright (c) 2013 Guntermann & Drunck GmbH
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <dm.h>
#include <tpm.h>
#include <asm/unaligned.h>
#include <u-boot/sha1.h>
/* Internal error of TPM command library */
#define TPM_LIB_ERROR ((uint32_t)~0u)
/* Useful constants */
enum {
COMMAND_BUFFER_SIZE = 256,
TPM_REQUEST_HEADER_LENGTH = 10,
TPM_RESPONSE_HEADER_LENGTH = 10,
PCR_DIGEST_LENGTH = 20,
DIGEST_LENGTH = 20,
TPM_REQUEST_AUTH_LENGTH = 45,
TPM_RESPONSE_AUTH_LENGTH = 41,
/* some max lengths, valid for RSA keys <= 2048 bits */
TPM_KEY12_MAX_LENGTH = 618,
TPM_PUBKEY_MAX_LENGTH = 288,
};
#ifdef CONFIG_TPM_AUTH_SESSIONS
#ifndef CONFIG_SHA1
#error "TPM_AUTH_SESSIONS require SHA1 to be configured, too"
#endif /* !CONFIG_SHA1 */
struct session_data {
int valid;
uint32_t handle;
uint8_t nonce_even[DIGEST_LENGTH];
uint8_t nonce_odd[DIGEST_LENGTH];
};
static struct session_data oiap_session = {0, };
#endif /* CONFIG_TPM_AUTH_SESSIONS */
/**
* Pack data into a byte string. The data types are specified in
* the format string: 'b' means unsigned byte, 'w' unsigned word,
* 'd' unsigned double word, and 's' byte string. The data are a
* series of offsets and values (for type byte string there are also
* lengths). The data values are packed into the byte string
* sequentially, and so a latter value could over-write a former
* value.
*
* @param str output string
* @param size size of output string
* @param format format string
* @param ... data points
* @return 0 on success, non-0 on error
*/
int pack_byte_string(uint8_t *str, size_t size, const char *format, ...)
{
va_list args;
size_t offset = 0, length = 0;
uint8_t *data = NULL;
uint32_t value = 0;
va_start(args, format);
for (; *format; format++) {
switch (*format) {
case 'b':
offset = va_arg(args, size_t);
value = va_arg(args, int);
length = 1;
break;
case 'w':
offset = va_arg(args, size_t);
value = va_arg(args, int);
length = 2;
break;
case 'd':
offset = va_arg(args, size_t);
value = va_arg(args, uint32_t);
length = 4;
break;
case 's':
offset = va_arg(args, size_t);
data = va_arg(args, uint8_t *);
length = va_arg(args, uint32_t);
break;
default:
debug("Couldn't recognize format string\n");
return -1;
}
if (offset + length > size)
return -1;
switch (*format) {
case 'b':
str[offset] = value;
break;
case 'w':
put_unaligned_be16(value, str + offset);
break;
case 'd':
put_unaligned_be32(value, str + offset);
break;
case 's':
memcpy(str + offset, data, length);
break;
}
}
va_end(args);
return 0;
}
/**
* Unpack data from a byte string. The data types are specified in
* the format string: 'b' means unsigned byte, 'w' unsigned word,
* 'd' unsigned double word, and 's' byte string. The data are a
* series of offsets and pointers (for type byte string there are also
* lengths).
*
* @param str output string
* @param size size of output string
* @param format format string
* @param ... data points
* @return 0 on success, non-0 on error
*/
int unpack_byte_string(const uint8_t *str, size_t size, const char *format, ...)
{
va_list args;
size_t offset = 0, length = 0;
uint8_t *ptr8 = NULL;
uint16_t *ptr16 = NULL;
uint32_t *ptr32 = NULL;
va_start(args, format);
for (; *format; format++) {
switch (*format) {
case 'b':
offset = va_arg(args, size_t);
ptr8 = va_arg(args, uint8_t *);
length = 1;
break;
case 'w':
offset = va_arg(args, size_t);
ptr16 = va_arg(args, uint16_t *);
length = 2;
break;
case 'd':
offset = va_arg(args, size_t);
ptr32 = va_arg(args, uint32_t *);
length = 4;
break;
case 's':
offset = va_arg(args, size_t);
ptr8 = va_arg(args, uint8_t *);
length = va_arg(args, uint32_t);
break;
default:
debug("Couldn't recognize format string\n");
return -1;
}
if (offset + length > size)
return -1;
switch (*format) {
case 'b':
*ptr8 = str[offset];
break;
case 'w':
*ptr16 = get_unaligned_be16(str + offset);
break;
case 'd':
*ptr32 = get_unaligned_be32(str + offset);
break;
case 's':
memcpy(ptr8, str + offset, length);
break;
}
}
va_end(args);
return 0;
}
/**
* Get TPM command size.
*
* @param command byte string of TPM command
* @return command size of the TPM command
*/
static uint32_t tpm_command_size(const void *command)
{
const size_t command_size_offset = 2;
return get_unaligned_be32(command + command_size_offset);
}
/**
* Get TPM response return code, which is one of TPM_RESULT values.
*
* @param response byte string of TPM response
* @return return code of the TPM response
*/
static uint32_t tpm_return_code(const void *response)
{
const size_t return_code_offset = 6;
return get_unaligned_be32(response + return_code_offset);
}
/**
* Send a TPM command and return response's return code, and optionally
* return response to caller.
*
* @param command byte string of TPM command
* @param response output buffer for TPM response, or NULL if the
* caller does not care about it
* @param size_ptr output buffer size (input parameter) and TPM
* response length (output parameter); this parameter
* is a bidirectional
* @return return code of the TPM response
*/
static uint32_t tpm_sendrecv_command(const void *command,
void *response, size_t *size_ptr)
{
struct udevice *dev;
int ret;
uint8_t response_buffer[COMMAND_BUFFER_SIZE];
size_t response_length;
uint32_t err;
if (response) {
response_length = *size_ptr;
} else {
response = response_buffer;
response_length = sizeof(response_buffer);
}
ret = uclass_first_device_err(UCLASS_TPM, &dev);
if (ret)
return ret;
err = tpm_xfer(dev, command, tpm_command_size(command),
response, &response_length);
if (err < 0)
return TPM_LIB_ERROR;
if (size_ptr)
*size_ptr = response_length;
return tpm_return_code(response);
}
int tpm_init(void)
{
int err;
struct udevice *dev;
err = uclass_first_device_err(UCLASS_TPM, &dev);
if (err)
return err;
return tpm_open(dev);
}
uint32_t tpm_startup(enum tpm_startup_type mode)
{
const uint8_t command[12] = {
0x0, 0xc1, 0x0, 0x0, 0x0, 0xc, 0x0, 0x0, 0x0, 0x99, 0x0, 0x0,
};
const size_t mode_offset = 10;
uint8_t buf[COMMAND_BUFFER_SIZE];
if (pack_byte_string(buf, sizeof(buf), "sw",
0, command, sizeof(command),
mode_offset, mode))
return TPM_LIB_ERROR;
return tpm_sendrecv_command(buf, NULL, NULL);
}
uint32_t tpm_self_test_full(void)
{
const uint8_t command[10] = {
0x0, 0xc1, 0x0, 0x0, 0x0, 0xa, 0x0, 0x0, 0x0, 0x50,
};
return tpm_sendrecv_command(command, NULL, NULL);
}
uint32_t tpm_continue_self_test(void)
{
const uint8_t command[10] = {
0x0, 0xc1, 0x0, 0x0, 0x0, 0xa, 0x0, 0x0, 0x0, 0x53,
};
return tpm_sendrecv_command(command, NULL, NULL);
}
uint32_t tpm_nv_define_space(uint32_t index, uint32_t perm, uint32_t size)
{
const uint8_t command[101] = {
0x0, 0xc1, /* TPM_TAG */
0x0, 0x0, 0x0, 0x65, /* parameter size */
0x0, 0x0, 0x0, 0xcc, /* TPM_COMMAND_CODE */
/* TPM_NV_DATA_PUBLIC->... */
0x0, 0x18, /* ...->TPM_STRUCTURE_TAG */
0, 0, 0, 0, /* ...->TPM_NV_INDEX */
/* TPM_NV_DATA_PUBLIC->TPM_PCR_INFO_SHORT */
0x0, 0x3,
0, 0, 0,
0x1f,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* TPM_NV_DATA_PUBLIC->TPM_PCR_INFO_SHORT */
0x0, 0x3,
0, 0, 0,
0x1f,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* TPM_NV_ATTRIBUTES->... */
0x0, 0x17, /* ...->TPM_STRUCTURE_TAG */
0, 0, 0, 0, /* ...->attributes */
/* End of TPM_NV_ATTRIBUTES */
0, /* bReadSTClear */
0, /* bWriteSTClear */
0, /* bWriteDefine */
0, 0, 0, 0, /* size */
};
const size_t index_offset = 12;
const size_t perm_offset = 70;
const size_t size_offset = 77;
uint8_t buf[COMMAND_BUFFER_SIZE];
if (pack_byte_string(buf, sizeof(buf), "sddd",
0, command, sizeof(command),
index_offset, index,
perm_offset, perm,
size_offset, size))
return TPM_LIB_ERROR;
return tpm_sendrecv_command(buf, NULL, NULL);
}
uint32_t tpm_nv_read_value(uint32_t index, void *data, uint32_t count)
{
const uint8_t command[22] = {
0x0, 0xc1, 0x0, 0x0, 0x0, 0x16, 0x0, 0x0, 0x0, 0xcf,
};
const size_t index_offset = 10;
const size_t length_offset = 18;
const size_t data_size_offset = 10;
const size_t data_offset = 14;
uint8_t buf[COMMAND_BUFFER_SIZE], response[COMMAND_BUFFER_SIZE];
size_t response_length = sizeof(response);
uint32_t data_size;
uint32_t err;
if (pack_byte_string(buf, sizeof(buf), "sdd",
0, command, sizeof(command),
index_offset, index,
length_offset, count))
return TPM_LIB_ERROR;
err = tpm_sendrecv_command(buf, response, &response_length);
if (err)
return err;
if (unpack_byte_string(response, response_length, "d",
data_size_offset, &data_size))
return TPM_LIB_ERROR;
if (data_size > count)
return TPM_LIB_ERROR;
if (unpack_byte_string(response, response_length, "s",
data_offset, data, data_size))
return TPM_LIB_ERROR;
return 0;
}
uint32_t tpm_nv_write_value(uint32_t index, const void *data, uint32_t length)
{
const uint8_t command[256] = {
0x0, 0xc1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0xcd,
};
const size_t command_size_offset = 2;
const size_t index_offset = 10;
const size_t length_offset = 18;
const size_t data_offset = 22;
const size_t write_info_size = 12;
const uint32_t total_length =
TPM_REQUEST_HEADER_LENGTH + write_info_size + length;
uint8_t buf[COMMAND_BUFFER_SIZE], response[COMMAND_BUFFER_SIZE];
size_t response_length = sizeof(response);
uint32_t err;
if (pack_byte_string(buf, sizeof(buf), "sddds",
0, command, sizeof(command),
command_size_offset, total_length,
index_offset, index,
length_offset, length,
data_offset, data, length))
return TPM_LIB_ERROR;
err = tpm_sendrecv_command(buf, response, &response_length);
if (err)
return err;
return 0;
}
uint32_t tpm_extend(uint32_t index, const void *in_digest, void *out_digest)
{
const uint8_t command[34] = {
0x0, 0xc1, 0x0, 0x0, 0x0, 0x22, 0x0, 0x0, 0x0, 0x14,
};
const size_t index_offset = 10;
const size_t in_digest_offset = 14;
const size_t out_digest_offset = 10;
uint8_t buf[COMMAND_BUFFER_SIZE];
uint8_t response[TPM_RESPONSE_HEADER_LENGTH + PCR_DIGEST_LENGTH];
size_t response_length = sizeof(response);
uint32_t err;
if (pack_byte_string(buf, sizeof(buf), "sds",
0, command, sizeof(command),
index_offset, index,
in_digest_offset, in_digest,
PCR_DIGEST_LENGTH))
return TPM_LIB_ERROR;
err = tpm_sendrecv_command(buf, response, &response_length);
if (err)
return err;
if (unpack_byte_string(response, response_length, "s",
out_digest_offset, out_digest,
PCR_DIGEST_LENGTH))
return TPM_LIB_ERROR;
return 0;
}
uint32_t tpm_pcr_read(uint32_t index, void *data, size_t count)
{
const uint8_t command[14] = {
0x0, 0xc1, 0x0, 0x0, 0x0, 0xe, 0x0, 0x0, 0x0, 0x15,
};
const size_t index_offset = 10;
const size_t out_digest_offset = 10;
uint8_t buf[COMMAND_BUFFER_SIZE], response[COMMAND_BUFFER_SIZE];
size_t response_length = sizeof(response);
uint32_t err;
if (count < PCR_DIGEST_LENGTH)
return TPM_LIB_ERROR;
if (pack_byte_string(buf, sizeof(buf), "sd",
0, command, sizeof(command),
index_offset, index))
return TPM_LIB_ERROR;
err = tpm_sendrecv_command(buf, response, &response_length);
if (err)
return err;
if (unpack_byte_string(response, response_length, "s",
out_digest_offset, data, PCR_DIGEST_LENGTH))
return TPM_LIB_ERROR;
return 0;
}
uint32_t tpm_tsc_physical_presence(uint16_t presence)
{
const uint8_t command[12] = {
0x0, 0xc1, 0x0, 0x0, 0x0, 0xc, 0x40, 0x0, 0x0, 0xa, 0x0, 0x0,
};
const size_t presence_offset = 10;
uint8_t buf[COMMAND_BUFFER_SIZE];
if (pack_byte_string(buf, sizeof(buf), "sw",
0, command, sizeof(command),
presence_offset, presence))
return TPM_LIB_ERROR;
return tpm_sendrecv_command(buf, NULL, NULL);
}
uint32_t tpm_read_pubek(void *data, size_t count)
{
const uint8_t command[30] = {
0x0, 0xc1, 0x0, 0x0, 0x0, 0x1e, 0x0, 0x0, 0x0, 0x7c,
};
const size_t response_size_offset = 2;
const size_t data_offset = 10;
const size_t header_and_checksum_size = TPM_RESPONSE_HEADER_LENGTH + 20;
uint8_t response[COMMAND_BUFFER_SIZE + TPM_PUBEK_SIZE];
size_t response_length = sizeof(response);
uint32_t data_size;
uint32_t err;
err = tpm_sendrecv_command(command, response, &response_length);
if (err)
return err;
if (unpack_byte_string(response, response_length, "d",
response_size_offset, &data_size))
return TPM_LIB_ERROR;
if (data_size < header_and_checksum_size)
return TPM_LIB_ERROR;
data_size -= header_and_checksum_size;
if (data_size > count)
return TPM_LIB_ERROR;
if (unpack_byte_string(response, response_length, "s",
data_offset, data, data_size))
return TPM_LIB_ERROR;
return 0;
}
uint32_t tpm_force_clear(void)
{
const uint8_t command[10] = {
0x0, 0xc1, 0x0, 0x0, 0x0, 0xa, 0x0, 0x0, 0x0, 0x5d,
};
return tpm_sendrecv_command(command, NULL, NULL);
}
uint32_t tpm_physical_enable(void)
{
const uint8_t command[10] = {
0x0, 0xc1, 0x0, 0x0, 0x0, 0xa, 0x0, 0x0, 0x0, 0x6f,
};
return tpm_sendrecv_command(command, NULL, NULL);
}
uint32_t tpm_physical_disable(void)
{
const uint8_t command[10] = {
0x0, 0xc1, 0x0, 0x0, 0x0, 0xa, 0x0, 0x0, 0x0, 0x70,
};
return tpm_sendrecv_command(command, NULL, NULL);
}
uint32_t tpm_physical_set_deactivated(uint8_t state)
{
const uint8_t command[11] = {
0x0, 0xc1, 0x0, 0x0, 0x0, 0xb, 0x0, 0x0, 0x0, 0x72,
};
const size_t state_offset = 10;
uint8_t buf[COMMAND_BUFFER_SIZE];
if (pack_byte_string(buf, sizeof(buf), "sb",
0, command, sizeof(command),
state_offset, state))
return TPM_LIB_ERROR;
return tpm_sendrecv_command(buf, NULL, NULL);
}
uint32_t tpm_get_capability(uint32_t cap_area, uint32_t sub_cap,
void *cap, size_t count)
{
const uint8_t command[22] = {
0x0, 0xc1, /* TPM_TAG */
0x0, 0x0, 0x0, 0x16, /* parameter size */
0x0, 0x0, 0x0, 0x65, /* TPM_COMMAND_CODE */
0x0, 0x0, 0x0, 0x0, /* TPM_CAPABILITY_AREA */
0x0, 0x0, 0x0, 0x4, /* subcap size */
0x0, 0x0, 0x0, 0x0, /* subcap value */
};
const size_t cap_area_offset = 10;
const size_t sub_cap_offset = 18;
const size_t cap_offset = 14;
const size_t cap_size_offset = 10;
uint8_t buf[COMMAND_BUFFER_SIZE], response[COMMAND_BUFFER_SIZE];
size_t response_length = sizeof(response);
uint32_t cap_size;
uint32_t err;
if (pack_byte_string(buf, sizeof(buf), "sdd",
0, command, sizeof(command),
cap_area_offset, cap_area,
sub_cap_offset, sub_cap))
return TPM_LIB_ERROR;
err = tpm_sendrecv_command(buf, response, &response_length);
if (err)
return err;
if (unpack_byte_string(response, response_length, "d",
cap_size_offset, &cap_size))
return TPM_LIB_ERROR;
if (cap_size > response_length || cap_size > count)
return TPM_LIB_ERROR;
if (unpack_byte_string(response, response_length, "s",
cap_offset, cap, cap_size))
return TPM_LIB_ERROR;
return 0;
}
uint32_t tpm_get_permanent_flags(struct tpm_permanent_flags *pflags)
{
const uint8_t command[22] = {
0x0, 0xc1, /* TPM_TAG */
0x0, 0x0, 0x0, 0x16, /* parameter size */
0x0, 0x0, 0x0, 0x65, /* TPM_COMMAND_CODE */
0x0, 0x0, 0x0, 0x4, /* TPM_CAP_FLAG_PERM */
0x0, 0x0, 0x0, 0x4, /* subcap size */
0x0, 0x0, 0x1, 0x8, /* subcap value */
};
uint8_t response[COMMAND_BUFFER_SIZE];
size_t response_length = sizeof(response);
uint32_t err;
err = tpm_sendrecv_command(command, response, &response_length);
if (err)
return err;
memcpy(pflags, response + TPM_HEADER_SIZE, sizeof(*pflags));
return 0;
}
uint32_t tpm_get_permissions(uint32_t index, uint32_t *perm)
{
const uint8_t command[22] = {
0x0, 0xc1, /* TPM_TAG */
0x0, 0x0, 0x0, 0x16, /* parameter size */
0x0, 0x0, 0x0, 0x65, /* TPM_COMMAND_CODE */
0x0, 0x0, 0x0, 0x11,
0x0, 0x0, 0x0, 0x4,
};
const size_t index_offset = 18;
const size_t perm_offset = 60;
uint8_t buf[COMMAND_BUFFER_SIZE], response[COMMAND_BUFFER_SIZE];
size_t response_length = sizeof(response);
uint32_t err;
if (pack_byte_string(buf, sizeof(buf), "d", 0, command, sizeof(command),
index_offset, index))
return TPM_LIB_ERROR;
err = tpm_sendrecv_command(buf, response, &response_length);
if (err)
return err;
if (unpack_byte_string(response, response_length, "d",
perm_offset, perm))
return TPM_LIB_ERROR;
return 0;
}
#ifdef CONFIG_TPM_FLUSH_RESOURCES
uint32_t tpm_flush_specific(uint32_t key_handle, uint32_t resource_type)
{
const uint8_t command[18] = {
0x00, 0xc1, /* TPM_TAG */
0x00, 0x00, 0x00, 0x12, /* parameter size */
0x00, 0x00, 0x00, 0xba, /* TPM_COMMAND_CODE */
0x00, 0x00, 0x00, 0x00, /* key handle */
0x00, 0x00, 0x00, 0x00, /* resource type */
};
const size_t key_handle_offset = 10;
const size_t resource_type_offset = 14;
uint8_t buf[COMMAND_BUFFER_SIZE], response[COMMAND_BUFFER_SIZE];
size_t response_length = sizeof(response);
uint32_t err;
if (pack_byte_string(buf, sizeof(buf), "sdd",
0, command, sizeof(command),
key_handle_offset, key_handle,
resource_type_offset, resource_type))
return TPM_LIB_ERROR;
err = tpm_sendrecv_command(buf, response, &response_length);
if (err)
return err;
return 0;
}
#endif /* CONFIG_TPM_FLUSH_RESOURCES */
#ifdef CONFIG_TPM_AUTH_SESSIONS
/**
* Fill an authentication block in a request.
* This func can create the first as well as the second auth block (for
* double authorized commands).
*
* @param request pointer to the request (w/ uninitialised auth data)
* @param request_len0 length of the request without auth data
* @param handles_len length of the handles area in request
* @param auth_session pointer to the (valid) auth session to be used
* @param request_auth pointer to the auth block of the request to be filled
* @param auth authentication data (HMAC key)
*/
static uint32_t create_request_auth(const void *request, size_t request_len0,
size_t handles_len,
struct session_data *auth_session,
void *request_auth, const void *auth)
{
uint8_t hmac_data[DIGEST_LENGTH * 3 + 1];
sha1_context hash_ctx;
const size_t command_code_offset = 6;
const size_t auth_nonce_odd_offset = 4;
const size_t auth_continue_offset = 24;
const size_t auth_auth_offset = 25;
if (!auth_session || !auth_session->valid)
return TPM_LIB_ERROR;
sha1_starts(&hash_ctx);
sha1_update(&hash_ctx, request + command_code_offset, 4);
if (request_len0 > TPM_REQUEST_HEADER_LENGTH + handles_len)
sha1_update(&hash_ctx,
request + TPM_REQUEST_HEADER_LENGTH + handles_len,
request_len0 - TPM_REQUEST_HEADER_LENGTH
- handles_len);
sha1_finish(&hash_ctx, hmac_data);
sha1_starts(&hash_ctx);
sha1_update(&hash_ctx, auth_session->nonce_odd, DIGEST_LENGTH);
sha1_update(&hash_ctx, hmac_data, sizeof(hmac_data));
sha1_finish(&hash_ctx, auth_session->nonce_odd);
if (pack_byte_string(request_auth, TPM_REQUEST_AUTH_LENGTH, "dsb",
0, auth_session->handle,
auth_nonce_odd_offset, auth_session->nonce_odd,
DIGEST_LENGTH,
auth_continue_offset, 1))
return TPM_LIB_ERROR;
if (pack_byte_string(hmac_data, sizeof(hmac_data), "ss",
DIGEST_LENGTH,
auth_session->nonce_even,
DIGEST_LENGTH,
2 * DIGEST_LENGTH,
request_auth + auth_nonce_odd_offset,
DIGEST_LENGTH + 1))
return TPM_LIB_ERROR;
sha1_hmac(auth, DIGEST_LENGTH, hmac_data, sizeof(hmac_data),
request_auth + auth_auth_offset);
return TPM_SUCCESS;
}
/**
* Verify an authentication block in a response.
* Since this func updates the nonce_even in the session data it has to be
* called when receiving a succesfull AUTH response.
* This func can verify the first as well as the second auth block (for
* double authorized commands).
*
* @param command_code command code of the request
* @param response pointer to the request (w/ uninitialised auth data)
* @param handles_len length of the handles area in response
* @param auth_session pointer to the (valid) auth session to be used
* @param response_auth pointer to the auth block of the response to be verified
* @param auth authentication data (HMAC key)
*/
static uint32_t verify_response_auth(uint32_t command_code,
const void *response, size_t response_len0,
size_t handles_len,
struct session_data *auth_session,
const void *response_auth, const void *auth)
{
uint8_t hmac_data[DIGEST_LENGTH * 3 + 1];
uint8_t computed_auth[DIGEST_LENGTH];
sha1_context hash_ctx;
const size_t return_code_offset = 6;
const size_t auth_continue_offset = 20;
const size_t auth_auth_offset = 21;
uint8_t auth_continue;
if (!auth_session || !auth_session->valid)
return TPM_AUTHFAIL;
if (pack_byte_string(hmac_data, sizeof(hmac_data), "d",
0, command_code))
return TPM_LIB_ERROR;
if (response_len0 < TPM_RESPONSE_HEADER_LENGTH)
return TPM_LIB_ERROR;
sha1_starts(&hash_ctx);
sha1_update(&hash_ctx, response + return_code_offset, 4);
sha1_update(&hash_ctx, hmac_data, 4);
if (response_len0 > TPM_RESPONSE_HEADER_LENGTH + handles_len)
sha1_update(&hash_ctx,
response + TPM_RESPONSE_HEADER_LENGTH + handles_len,
response_len0 - TPM_RESPONSE_HEADER_LENGTH
- handles_len);
sha1_finish(&hash_ctx, hmac_data);
memcpy(auth_session->nonce_even, response_auth, DIGEST_LENGTH);
auth_continue = ((uint8_t *)response_auth)[auth_continue_offset];
if (pack_byte_string(hmac_data, sizeof(hmac_data), "ssb",
DIGEST_LENGTH,
response_auth,
DIGEST_LENGTH,
2 * DIGEST_LENGTH,
auth_session->nonce_odd,
DIGEST_LENGTH,
3 * DIGEST_LENGTH,
auth_continue))
return TPM_LIB_ERROR;
sha1_hmac(auth, DIGEST_LENGTH, hmac_data, sizeof(hmac_data),
computed_auth);
if (memcmp(computed_auth, response_auth + auth_auth_offset,
DIGEST_LENGTH))
return TPM_AUTHFAIL;
return TPM_SUCCESS;
}
uint32_t tpm_terminate_auth_session(uint32_t auth_handle)
{
const uint8_t command[18] = {
0x00, 0xc1, /* TPM_TAG */
0x00, 0x00, 0x00, 0x00, /* parameter size */
0x00, 0x00, 0x00, 0xba, /* TPM_COMMAND_CODE */
0x00, 0x00, 0x00, 0x00, /* TPM_HANDLE */
0x00, 0x00, 0x00, 0x02, /* TPM_RESSOURCE_TYPE */
};
const size_t req_handle_offset = TPM_REQUEST_HEADER_LENGTH;
uint8_t request[COMMAND_BUFFER_SIZE];
if (pack_byte_string(request, sizeof(request), "sd",
0, command, sizeof(command),
req_handle_offset, auth_handle))
return TPM_LIB_ERROR;
if (oiap_session.valid && oiap_session.handle == auth_handle)
oiap_session.valid = 0;
return tpm_sendrecv_command(request, NULL, NULL);
}
uint32_t tpm_end_oiap(void)
{
uint32_t err = TPM_SUCCESS;
if (oiap_session.valid)
err = tpm_terminate_auth_session(oiap_session.handle);
return err;
}
uint32_t tpm_oiap(uint32_t *auth_handle)
{
const uint8_t command[10] = {
0x00, 0xc1, /* TPM_TAG */
0x00, 0x00, 0x00, 0x0a, /* parameter size */
0x00, 0x00, 0x00, 0x0a, /* TPM_COMMAND_CODE */
};
const size_t res_auth_handle_offset = TPM_RESPONSE_HEADER_LENGTH;
const size_t res_nonce_even_offset = TPM_RESPONSE_HEADER_LENGTH + 4;
uint8_t response[COMMAND_BUFFER_SIZE];
size_t response_length = sizeof(response);
uint32_t err;
if (oiap_session.valid)
tpm_terminate_auth_session(oiap_session.handle);
err = tpm_sendrecv_command(command, response, &response_length);
if (err)
return err;
if (unpack_byte_string(response, response_length, "ds",
res_auth_handle_offset, &oiap_session.handle,
res_nonce_even_offset, &oiap_session.nonce_even,
(uint32_t)DIGEST_LENGTH))
return TPM_LIB_ERROR;
oiap_session.valid = 1;
if (auth_handle)
*auth_handle = oiap_session.handle;
return 0;
}
uint32_t tpm_load_key2_oiap(uint32_t parent_handle,
const void *key, size_t key_length,
const void *parent_key_usage_auth,
uint32_t *key_handle)
{
const uint8_t command[14] = {
0x00, 0xc2, /* TPM_TAG */
0x00, 0x00, 0x00, 0x00, /* parameter size */
0x00, 0x00, 0x00, 0x41, /* TPM_COMMAND_CODE */
0x00, 0x00, 0x00, 0x00, /* parent handle */
};
const size_t req_size_offset = 2;
const size_t req_parent_handle_offset = TPM_REQUEST_HEADER_LENGTH;
const size_t req_key_offset = TPM_REQUEST_HEADER_LENGTH + 4;
const size_t res_handle_offset = TPM_RESPONSE_HEADER_LENGTH;
uint8_t request[sizeof(command) + TPM_KEY12_MAX_LENGTH
+ TPM_REQUEST_AUTH_LENGTH];
uint8_t response[COMMAND_BUFFER_SIZE];
size_t response_length = sizeof(response);
uint32_t err;
if (!oiap_session.valid) {
err = tpm_oiap(NULL);
if (err)
return err;
}
if (pack_byte_string(request, sizeof(request), "sdds",
0, command, sizeof(command),
req_size_offset,
sizeof(command) + key_length
+ TPM_REQUEST_AUTH_LENGTH,
req_parent_handle_offset, parent_handle,
req_key_offset, key, key_length
))
return TPM_LIB_ERROR;
err = create_request_auth(request, sizeof(command) + key_length, 4,
&oiap_session,
request + sizeof(command) + key_length,
parent_key_usage_auth);
if (err)
return err;
err = tpm_sendrecv_command(request, response, &response_length);
if (err) {
if (err == TPM_AUTHFAIL)
oiap_session.valid = 0;
return err;
}
err = verify_response_auth(0x00000041, response,
response_length - TPM_RESPONSE_AUTH_LENGTH,
4, &oiap_session,
response + response_length - TPM_RESPONSE_AUTH_LENGTH,
parent_key_usage_auth);
if (err)
return err;
if (key_handle) {
if (unpack_byte_string(response, response_length, "d",
res_handle_offset, key_handle))
return TPM_LIB_ERROR;
}
return 0;
}
uint32_t tpm_get_pub_key_oiap(uint32_t key_handle, const void *usage_auth,
void *pubkey, size_t *pubkey_len)
{
const uint8_t command[14] = {
0x00, 0xc2, /* TPM_TAG */
0x00, 0x00, 0x00, 0x00, /* parameter size */
0x00, 0x00, 0x00, 0x21, /* TPM_COMMAND_CODE */
0x00, 0x00, 0x00, 0x00, /* key handle */
};
const size_t req_size_offset = 2;
const size_t req_key_handle_offset = TPM_REQUEST_HEADER_LENGTH;
const size_t res_pubkey_offset = TPM_RESPONSE_HEADER_LENGTH;
uint8_t request[sizeof(command) + TPM_REQUEST_AUTH_LENGTH];
uint8_t response[TPM_RESPONSE_HEADER_LENGTH + TPM_PUBKEY_MAX_LENGTH
+ TPM_RESPONSE_AUTH_LENGTH];
size_t response_length = sizeof(response);
uint32_t err;
if (!oiap_session.valid) {
err = tpm_oiap(NULL);
if (err)
return err;
}
if (pack_byte_string(request, sizeof(request), "sdd",
0, command, sizeof(command),
req_size_offset,
(uint32_t)(sizeof(command)
+ TPM_REQUEST_AUTH_LENGTH),
req_key_handle_offset, key_handle
))
return TPM_LIB_ERROR;
err = create_request_auth(request, sizeof(command), 4, &oiap_session,
request + sizeof(command), usage_auth);
if (err)
return err;
err = tpm_sendrecv_command(request, response, &response_length);
if (err) {
if (err == TPM_AUTHFAIL)
oiap_session.valid = 0;
return err;
}
err = verify_response_auth(0x00000021, response,
response_length - TPM_RESPONSE_AUTH_LENGTH,
0, &oiap_session,
response + response_length - TPM_RESPONSE_AUTH_LENGTH,
usage_auth);
if (err)
return err;
if (pubkey) {
if ((response_length - TPM_RESPONSE_HEADER_LENGTH
- TPM_RESPONSE_AUTH_LENGTH) > *pubkey_len)
return TPM_LIB_ERROR;
*pubkey_len = response_length - TPM_RESPONSE_HEADER_LENGTH
- TPM_RESPONSE_AUTH_LENGTH;
memcpy(pubkey, response + res_pubkey_offset,
response_length - TPM_RESPONSE_HEADER_LENGTH
- TPM_RESPONSE_AUTH_LENGTH);
}
return 0;
}
#ifdef CONFIG_TPM_LOAD_KEY_BY_SHA1
uint32_t tpm_find_key_sha1(const uint8_t auth[20], const uint8_t
pubkey_digest[20], uint32_t *handle)
{
uint16_t key_count;
uint32_t key_handles[10];
uint8_t buf[288];
uint8_t *ptr;
uint32_t err;
uint8_t digest[20];
size_t buf_len;
unsigned int i;
/* fetch list of already loaded keys in the TPM */
err = tpm_get_capability(TPM_CAP_HANDLE, TPM_RT_KEY, buf, sizeof(buf));
if (err)
return -1;
key_count = get_unaligned_be16(buf);
ptr = buf + 2;
for (i = 0; i < key_count; ++i, ptr += 4)
key_handles[i] = get_unaligned_be32(ptr);
/* now search a(/ the) key which we can access with the given auth */
for (i = 0; i < key_count; ++i) {
buf_len = sizeof(buf);
err = tpm_get_pub_key_oiap(key_handles[i], auth, buf, &buf_len);
if (err && err != TPM_AUTHFAIL)
return -1;
if (err)
continue;
sha1_csum(buf, buf_len, digest);
if (!memcmp(digest, pubkey_digest, 20)) {
*handle = key_handles[i];
return 0;
}
}
return 1;
}
#endif /* CONFIG_TPM_LOAD_KEY_BY_SHA1 */
#endif /* CONFIG_TPM_AUTH_SESSIONS */
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