lib/tpm.c

/*
 * 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)
{
	static 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)
{
	static 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)
{
	static 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)
{
	static 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)
{
	static 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)
{
	static 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)
{
	static 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)
{
	static 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)
{
	static 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)
{
	static 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)
{
	static 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)
{
	static 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)
{
	static 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)
{
	static 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)
{
	static 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;
}