tpm: Add TPM command library
TPM command library implements a subset of TPM commands defined in TCG
Main Specification 1.2 that are useful for implementing secure boot.
More TPM commands could be added out of necessity.
You may exercise these commands through the 'tpm' command. However, the
raw TPM commands are too primitive for writing secure boot in command
interpreter scripts; so the 'tpm' command also provides helper functions
to make scripting easier.
For example, to define a counter in TPM non-volatile storage and
initialize it to zero:
$ tpm init
$ tpm startup TPM_ST_CLEAR
$ tpm nv_define d 0x1001 0x1
$ tpm nv_write d 0x1001 0
And then increment the counter by one:
$ tpm nv_read d 0x1001 i
$ setexpr.l i $i + 1
$ tpm nv_write d 0x1001 $i
Signed-off-by: Che-Liang Chiou <clchiou@chromium.org>
diff --git a/lib/tpm.c b/lib/tpm.c
new file mode 100644
index 0000000..42c9bea
--- /dev/null
+++ b/lib/tpm.c
@@ -0,0 +1,581 @@
+/*
+ * Copyright (c) 2013 The Chromium OS Authors.
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <common.h>
+#include <stdarg.h>
+#include <tpm.h>
+#include <asm/unaligned.h>
+
+/* Internal error of TPM command library */
+#define TPM_LIB_ERROR ((uint32_t)~0u)
+
+/* Useful constants */
+enum {
+ COMMAND_BUFFER_SIZE = 256,
+ TPM_PUBEK_SIZE = 256,
+ TPM_REQUEST_HEADER_LENGTH = 10,
+ TPM_RESPONSE_HEADER_LENGTH = 10,
+ PCR_DIGEST_LENGTH = 20,
+};
+
+/**
+ * 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)
+{
+ 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);
+ }
+ err = tis_sendrecv(command, tpm_command_size(command),
+ response, &response_length);
+ if (err)
+ return TPM_LIB_ERROR;
+ if (response)
+ *size_ptr = response_length;
+
+ return tpm_return_code(response);
+}
+
+uint32_t tpm_init(void)
+{
+ uint32_t err;
+
+ err = tis_init();
+ if (err)
+ return err;
+
+ return tis_open();
+}
+
+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;
+}