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linux/drivers/char/tpm/tpm2-cmd.c

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/*
* Copyright (C) 2014 Intel Corporation
*
* Authors:
* Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
*
* Maintained by: <tpmdd-devel@lists.sourceforge.net>
*
* This file contains TPM2 protocol implementations of the commands
* used by the kernel internally.
*
* 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; version 2
* of the License.
*/
#include "tpm.h"
struct tpm2_startup_in {
__be16 startup_type;
} __packed;
struct tpm2_self_test_in {
u8 full_test;
} __packed;
struct tpm2_pcr_read_in {
__be32 pcr_selects_cnt;
__be16 hash_alg;
u8 pcr_select_size;
u8 pcr_select[TPM2_PCR_SELECT_MIN];
} __packed;
struct tpm2_pcr_read_out {
__be32 update_cnt;
__be32 pcr_selects_cnt;
__be16 hash_alg;
u8 pcr_select_size;
u8 pcr_select[TPM2_PCR_SELECT_MIN];
__be32 digests_cnt;
__be16 digest_size;
u8 digest[TPM_DIGEST_SIZE];
} __packed;
struct tpm2_null_auth_area {
__be32 handle;
__be16 nonce_size;
u8 attributes;
__be16 auth_size;
} __packed;
struct tpm2_pcr_extend_in {
__be32 pcr_idx;
__be32 auth_area_size;
struct tpm2_null_auth_area auth_area;
__be32 digest_cnt;
__be16 hash_alg;
u8 digest[TPM_DIGEST_SIZE];
} __packed;
struct tpm2_get_tpm_pt_in {
__be32 cap_id;
__be32 property_id;
__be32 property_cnt;
} __packed;
struct tpm2_get_tpm_pt_out {
u8 more_data;
__be32 subcap_id;
__be32 property_cnt;
__be32 property_id;
__be32 value;
} __packed;
struct tpm2_get_random_in {
__be16 size;
} __packed;
struct tpm2_get_random_out {
__be16 size;
u8 buffer[TPM_MAX_RNG_DATA];
} __packed;
union tpm2_cmd_params {
struct tpm2_startup_in startup_in;
struct tpm2_self_test_in selftest_in;
struct tpm2_pcr_read_in pcrread_in;
struct tpm2_pcr_read_out pcrread_out;
struct tpm2_pcr_extend_in pcrextend_in;
struct tpm2_get_tpm_pt_in get_tpm_pt_in;
struct tpm2_get_tpm_pt_out get_tpm_pt_out;
struct tpm2_get_random_in getrandom_in;
struct tpm2_get_random_out getrandom_out;
};
struct tpm2_cmd {
tpm_cmd_header header;
union tpm2_cmd_params params;
} __packed;
/*
* Array with one entry per ordinal defining the maximum amount
* of time the chip could take to return the result. The values
* of the SHORT, MEDIUM, and LONG durations are taken from the
* PC Client Profile (PTP) specification.
*/
static const u8 tpm2_ordinal_duration[TPM2_CC_LAST - TPM2_CC_FIRST + 1] = {
TPM_UNDEFINED, /* 11F */
TPM_UNDEFINED, /* 120 */
TPM_LONG, /* 121 */
TPM_UNDEFINED, /* 122 */
TPM_UNDEFINED, /* 123 */
TPM_UNDEFINED, /* 124 */
TPM_UNDEFINED, /* 125 */
TPM_UNDEFINED, /* 126 */
TPM_UNDEFINED, /* 127 */
TPM_UNDEFINED, /* 128 */
TPM_LONG, /* 129 */
TPM_UNDEFINED, /* 12a */
TPM_UNDEFINED, /* 12b */
TPM_UNDEFINED, /* 12c */
TPM_UNDEFINED, /* 12d */
TPM_UNDEFINED, /* 12e */
TPM_UNDEFINED, /* 12f */
TPM_UNDEFINED, /* 130 */
TPM_UNDEFINED, /* 131 */
TPM_UNDEFINED, /* 132 */
TPM_UNDEFINED, /* 133 */
TPM_UNDEFINED, /* 134 */
TPM_UNDEFINED, /* 135 */
TPM_UNDEFINED, /* 136 */
TPM_UNDEFINED, /* 137 */
TPM_UNDEFINED, /* 138 */
TPM_UNDEFINED, /* 139 */
TPM_UNDEFINED, /* 13a */
TPM_UNDEFINED, /* 13b */
TPM_UNDEFINED, /* 13c */
TPM_UNDEFINED, /* 13d */
TPM_MEDIUM, /* 13e */
TPM_UNDEFINED, /* 13f */
TPM_UNDEFINED, /* 140 */
TPM_UNDEFINED, /* 141 */
TPM_UNDEFINED, /* 142 */
TPM_LONG, /* 143 */
TPM_MEDIUM, /* 144 */
TPM_UNDEFINED, /* 145 */
TPM_UNDEFINED, /* 146 */
TPM_UNDEFINED, /* 147 */
TPM_UNDEFINED, /* 148 */
TPM_UNDEFINED, /* 149 */
TPM_UNDEFINED, /* 14a */
TPM_UNDEFINED, /* 14b */
TPM_UNDEFINED, /* 14c */
TPM_UNDEFINED, /* 14d */
TPM_LONG, /* 14e */
TPM_UNDEFINED, /* 14f */
TPM_UNDEFINED, /* 150 */
TPM_UNDEFINED, /* 151 */
TPM_UNDEFINED, /* 152 */
TPM_UNDEFINED, /* 153 */
TPM_UNDEFINED, /* 154 */
TPM_UNDEFINED, /* 155 */
TPM_UNDEFINED, /* 156 */
TPM_UNDEFINED, /* 157 */
TPM_UNDEFINED, /* 158 */
TPM_UNDEFINED, /* 159 */
TPM_UNDEFINED, /* 15a */
TPM_UNDEFINED, /* 15b */
TPM_MEDIUM, /* 15c */
TPM_UNDEFINED, /* 15d */
TPM_UNDEFINED, /* 15e */
TPM_UNDEFINED, /* 15f */
TPM_UNDEFINED, /* 160 */
TPM_UNDEFINED, /* 161 */
TPM_UNDEFINED, /* 162 */
TPM_UNDEFINED, /* 163 */
TPM_UNDEFINED, /* 164 */
TPM_UNDEFINED, /* 165 */
TPM_UNDEFINED, /* 166 */
TPM_UNDEFINED, /* 167 */
TPM_UNDEFINED, /* 168 */
TPM_UNDEFINED, /* 169 */
TPM_UNDEFINED, /* 16a */
TPM_UNDEFINED, /* 16b */
TPM_UNDEFINED, /* 16c */
TPM_UNDEFINED, /* 16d */
TPM_UNDEFINED, /* 16e */
TPM_UNDEFINED, /* 16f */
TPM_UNDEFINED, /* 170 */
TPM_UNDEFINED, /* 171 */
TPM_UNDEFINED, /* 172 */
TPM_UNDEFINED, /* 173 */
TPM_UNDEFINED, /* 174 */
TPM_UNDEFINED, /* 175 */
TPM_UNDEFINED, /* 176 */
TPM_LONG, /* 177 */
TPM_UNDEFINED, /* 178 */
TPM_UNDEFINED, /* 179 */
TPM_MEDIUM, /* 17a */
TPM_LONG, /* 17b */
TPM_UNDEFINED, /* 17c */
TPM_UNDEFINED, /* 17d */
TPM_UNDEFINED, /* 17e */
TPM_UNDEFINED, /* 17f */
TPM_UNDEFINED, /* 180 */
TPM_UNDEFINED, /* 181 */
TPM_MEDIUM, /* 182 */
TPM_UNDEFINED, /* 183 */
TPM_UNDEFINED, /* 184 */
TPM_MEDIUM, /* 185 */
TPM_MEDIUM, /* 186 */
TPM_UNDEFINED, /* 187 */
TPM_UNDEFINED, /* 188 */
TPM_UNDEFINED, /* 189 */
TPM_UNDEFINED, /* 18a */
TPM_UNDEFINED, /* 18b */
TPM_UNDEFINED, /* 18c */
TPM_UNDEFINED, /* 18d */
TPM_UNDEFINED, /* 18e */
TPM_UNDEFINED /* 18f */
};
#define TPM2_PCR_READ_IN_SIZE \
(sizeof(struct tpm_input_header) + \
sizeof(struct tpm2_pcr_read_in))
static const struct tpm_input_header tpm2_pcrread_header = {
.tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
.length = cpu_to_be32(TPM2_PCR_READ_IN_SIZE),
.ordinal = cpu_to_be32(TPM2_CC_PCR_READ)
};
/**
* tpm2_pcr_read() - read a PCR value
* @chip: TPM chip to use.
* @pcr_idx: index of the PCR to read.
* @ref_buf: buffer to store the resulting hash,
*
* 0 is returned when the operation is successful. If a negative number is
* returned it remarks a POSIX error code. If a positive number is returned
* it remarks a TPM error.
*/
int tpm2_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
{
int rc;
struct tpm2_cmd cmd;
u8 *buf;
if (pcr_idx >= TPM2_PLATFORM_PCR)
return -EINVAL;
cmd.header.in = tpm2_pcrread_header;
cmd.params.pcrread_in.pcr_selects_cnt = cpu_to_be32(1);
cmd.params.pcrread_in.hash_alg = cpu_to_be16(TPM2_ALG_SHA1);
cmd.params.pcrread_in.pcr_select_size = TPM2_PCR_SELECT_MIN;
memset(cmd.params.pcrread_in.pcr_select, 0,
sizeof(cmd.params.pcrread_in.pcr_select));
cmd.params.pcrread_in.pcr_select[pcr_idx >> 3] = 1 << (pcr_idx & 0x7);
rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd),
"attempting to read a pcr value");
if (rc == 0) {
buf = cmd.params.pcrread_out.digest;
memcpy(res_buf, buf, TPM_DIGEST_SIZE);
}
return rc;
}
#define TPM2_GET_PCREXTEND_IN_SIZE \
(sizeof(struct tpm_input_header) + \
sizeof(struct tpm2_pcr_extend_in))
static const struct tpm_input_header tpm2_pcrextend_header = {
.tag = cpu_to_be16(TPM2_ST_SESSIONS),
.length = cpu_to_be32(TPM2_GET_PCREXTEND_IN_SIZE),
.ordinal = cpu_to_be32(TPM2_CC_PCR_EXTEND)
};
/**
* tpm2_pcr_extend() - extend a PCR value
* @chip: TPM chip to use.
* @pcr_idx: index of the PCR.
* @hash: hash value to use for the extend operation.
*
* 0 is returned when the operation is successful. If a negative number is
* returned it remarks a POSIX error code. If a positive number is returned
* it remarks a TPM error.
*/
int tpm2_pcr_extend(struct tpm_chip *chip, int pcr_idx, const u8 *hash)
{
struct tpm2_cmd cmd;
int rc;
cmd.header.in = tpm2_pcrextend_header;
cmd.params.pcrextend_in.pcr_idx = cpu_to_be32(pcr_idx);
cmd.params.pcrextend_in.auth_area_size =
cpu_to_be32(sizeof(struct tpm2_null_auth_area));
cmd.params.pcrextend_in.auth_area.handle =
cpu_to_be32(TPM2_RS_PW);
cmd.params.pcrextend_in.auth_area.nonce_size = 0;
cmd.params.pcrextend_in.auth_area.attributes = 0;
cmd.params.pcrextend_in.auth_area.auth_size = 0;
cmd.params.pcrextend_in.digest_cnt = cpu_to_be32(1);
cmd.params.pcrextend_in.hash_alg = cpu_to_be16(TPM2_ALG_SHA1);
memcpy(cmd.params.pcrextend_in.digest, hash, TPM_DIGEST_SIZE);
rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd),
"attempting extend a PCR value");
return rc;
}
#define TPM2_GETRANDOM_IN_SIZE \
(sizeof(struct tpm_input_header) + \
sizeof(struct tpm2_get_random_in))
static const struct tpm_input_header tpm2_getrandom_header = {
.tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
.length = cpu_to_be32(TPM2_GETRANDOM_IN_SIZE),
.ordinal = cpu_to_be32(TPM2_CC_GET_RANDOM)
};
/**
* tpm2_get_random() - get random bytes from the TPM RNG
* @chip: TPM chip to use
* @out: destination buffer for the random bytes
* @max: the max number of bytes to write to @out
*
* 0 is returned when the operation is successful. If a negative number is
* returned it remarks a POSIX error code. If a positive number is returned
* it remarks a TPM error.
*/
int tpm2_get_random(struct tpm_chip *chip, u8 *out, size_t max)
{
struct tpm2_cmd cmd;
u32 recd;
u32 num_bytes;
int err;
int total = 0;
int retries = 5;
u8 *dest = out;
num_bytes = min_t(u32, max, sizeof(cmd.params.getrandom_out.buffer));
if (!out || !num_bytes ||
max > sizeof(cmd.params.getrandom_out.buffer))
return -EINVAL;
do {
cmd.header.in = tpm2_getrandom_header;
cmd.params.getrandom_in.size = cpu_to_be16(num_bytes);
err = tpm_transmit_cmd(chip, &cmd, sizeof(cmd),
"attempting get random");
if (err)
break;
recd = min_t(u32, be16_to_cpu(cmd.params.getrandom_out.size),
num_bytes);
memcpy(dest, cmd.params.getrandom_out.buffer, recd);
dest += recd;
total += recd;
num_bytes -= recd;
} while (retries-- && total < max);
return total ? total : -EIO;
}
#define TPM2_GET_TPM_PT_IN_SIZE \
(sizeof(struct tpm_input_header) + \
sizeof(struct tpm2_get_tpm_pt_in))
static const struct tpm_input_header tpm2_get_tpm_pt_header = {
.tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
.length = cpu_to_be32(TPM2_GET_TPM_PT_IN_SIZE),
.ordinal = cpu_to_be32(TPM2_CC_GET_CAPABILITY)
};
/**
* tpm2_get_tpm_pt() - get value of a TPM_CAP_TPM_PROPERTIES type property
* @chip: TPM chip to use.
* @property_id: property ID.
* @value: output variable.
* @desc: passed to tpm_transmit_cmd()
*
* 0 is returned when the operation is successful. If a negative number is
* returned it remarks a POSIX error code. If a positive number is returned
* it remarks a TPM error.
*/
ssize_t tpm2_get_tpm_pt(struct tpm_chip *chip, u32 property_id, u32 *value,
const char *desc)
{
struct tpm2_cmd cmd;
int rc;
cmd.header.in = tpm2_get_tpm_pt_header;
cmd.params.get_tpm_pt_in.cap_id = cpu_to_be32(TPM2_CAP_TPM_PROPERTIES);
cmd.params.get_tpm_pt_in.property_id = cpu_to_be32(property_id);
cmd.params.get_tpm_pt_in.property_cnt = cpu_to_be32(1);
rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd), desc);
if (!rc)
*value = cmd.params.get_tpm_pt_out.value;
return rc;
}
#define TPM2_STARTUP_IN_SIZE \
(sizeof(struct tpm_input_header) + \
sizeof(struct tpm2_startup_in))
static const struct tpm_input_header tpm2_startup_header = {
.tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
.length = cpu_to_be32(TPM2_STARTUP_IN_SIZE),
.ordinal = cpu_to_be32(TPM2_CC_STARTUP)
};
/**
* tpm2_startup() - send startup command to the TPM chip
* @chip: TPM chip to use.
* @startup_type startup type. The value is either
* TPM_SU_CLEAR or TPM_SU_STATE.
*
* 0 is returned when the operation is successful. If a negative number is
* returned it remarks a POSIX error code. If a positive number is returned
* it remarks a TPM error.
*/
int tpm2_startup(struct tpm_chip *chip, u16 startup_type)
{
struct tpm2_cmd cmd;
cmd.header.in = tpm2_startup_header;
cmd.params.startup_in.startup_type = cpu_to_be16(startup_type);
return tpm_transmit_cmd(chip, &cmd, sizeof(cmd),
"attempting to start the TPM");
}
EXPORT_SYMBOL_GPL(tpm2_startup);
#define TPM2_SHUTDOWN_IN_SIZE \
(sizeof(struct tpm_input_header) + \
sizeof(struct tpm2_startup_in))
static const struct tpm_input_header tpm2_shutdown_header = {
.tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
.length = cpu_to_be32(TPM2_SHUTDOWN_IN_SIZE),
.ordinal = cpu_to_be32(TPM2_CC_SHUTDOWN)
};
/**
* tpm2_shutdown() - send shutdown command to the TPM chip
* @chip: TPM chip to use.
* @shutdown_type shutdown type. The value is either
* TPM_SU_CLEAR or TPM_SU_STATE.
*/
void tpm2_shutdown(struct tpm_chip *chip, u16 shutdown_type)
{
struct tpm2_cmd cmd;
int rc;
cmd.header.in = tpm2_shutdown_header;
cmd.params.startup_in.startup_type = cpu_to_be16(shutdown_type);
rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd), "stopping the TPM");
/* In places where shutdown command is sent there's no much we can do
* except print the error code on a system failure.
*/
if (rc < 0)
dev_warn(chip->pdev, "transmit returned %d while stopping the TPM",
rc);
}
EXPORT_SYMBOL_GPL(tpm2_shutdown);
/*
* tpm2_calc_ordinal_duration() - maximum duration for a command
* @chip: TPM chip to use.
* @ordinal: command code number.
*
* 0 is returned when the operation is successful. If a negative number is
* returned it remarks a POSIX error code. If a positive number is returned
* it remarks a TPM error.
*/
unsigned long tpm2_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal)
{
int index = TPM_UNDEFINED;
int duration = 0;
if (ordinal >= TPM2_CC_FIRST && ordinal <= TPM2_CC_LAST)
index = tpm2_ordinal_duration[ordinal - TPM2_CC_FIRST];
if (index != TPM_UNDEFINED)
duration = chip->vendor.duration[index];
if (duration <= 0)
duration = 2 * 60 * HZ;
return duration;
}
EXPORT_SYMBOL_GPL(tpm2_calc_ordinal_duration);
#define TPM2_SELF_TEST_IN_SIZE \
(sizeof(struct tpm_input_header) + \
sizeof(struct tpm2_self_test_in))
static const struct tpm_input_header tpm2_selftest_header = {
.tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
.length = cpu_to_be32(TPM2_SELF_TEST_IN_SIZE),
.ordinal = cpu_to_be32(TPM2_CC_SELF_TEST)
};
/**
* tpm2_continue_selftest() - start a self test
* @chip: TPM chip to use
* @full: test all commands instead of testing only those that were not
* previously tested.
*
* 0 is returned when the operation is successful. If a negative number is
* returned it remarks a POSIX error code. If a positive number is returned
* it remarks a TPM error.
*/
static int tpm2_start_selftest(struct tpm_chip *chip, bool full)
{
int rc;
struct tpm2_cmd cmd;
cmd.header.in = tpm2_selftest_header;
cmd.params.selftest_in.full_test = full;
rc = tpm_transmit_cmd(chip, &cmd, TPM2_SELF_TEST_IN_SIZE,
"continue selftest");
/* At least some prototype chips seem to give RC_TESTING error
* immediately. This is a workaround for that.
*/
if (rc == TPM2_RC_TESTING) {
dev_warn(chip->pdev, "Got RC_TESTING, ignoring\n");
rc = 0;
}
return rc;
}
/**
* tpm2_do_selftest() - run a full self test
* @chip: TPM chip to use
*
* During the self test TPM2 commands return with the error code RC_TESTING.
* Waiting is done by issuing PCR read until it executes successfully.
*
* 0 is returned when the operation is successful. If a negative number is
* returned it remarks a POSIX error code. If a positive number is returned
* it remarks a TPM error.
*/
int tpm2_do_selftest(struct tpm_chip *chip)
{
int rc;
unsigned int loops;
unsigned int delay_msec = 100;
unsigned long duration;
struct tpm2_cmd cmd;
int i;
duration = tpm2_calc_ordinal_duration(chip, TPM2_CC_SELF_TEST);
loops = jiffies_to_msecs(duration) / delay_msec;
rc = tpm2_start_selftest(chip, true);
if (rc)
return rc;
for (i = 0; i < loops; i++) {
/* Attempt to read a PCR value */
cmd.header.in = tpm2_pcrread_header;
cmd.params.pcrread_in.pcr_selects_cnt = cpu_to_be32(1);
cmd.params.pcrread_in.hash_alg = cpu_to_be16(TPM2_ALG_SHA1);
cmd.params.pcrread_in.pcr_select_size = TPM2_PCR_SELECT_MIN;
cmd.params.pcrread_in.pcr_select[0] = 0x01;
cmd.params.pcrread_in.pcr_select[1] = 0x00;
cmd.params.pcrread_in.pcr_select[2] = 0x00;
rc = tpm_transmit_cmd(chip, (u8 *) &cmd, sizeof(cmd), NULL);
if (rc < 0)
break;
rc = be32_to_cpu(cmd.header.out.return_code);
if (rc != TPM2_RC_TESTING)
break;
msleep(delay_msec);
}
return rc;
}
EXPORT_SYMBOL_GPL(tpm2_do_selftest);
/**
* tpm2_gen_interrupt() - generate an interrupt
* @chip: TPM chip to use
*
* 0 is returned when the operation is successful. If a negative number is
* returned it remarks a POSIX error code. If a positive number is returned
* it remarks a TPM error.
*/
int tpm2_gen_interrupt(struct tpm_chip *chip)
{
u32 dummy;
return tpm2_get_tpm_pt(chip, 0x100, &dummy,
"attempting to generate an interrupt");
}
EXPORT_SYMBOL_GPL(tpm2_gen_interrupt);
/**
* tpm2_probe() - probe TPM 2.0
* @chip: TPM chip to use
*
* Send idempotent TPM 2.0 command and see whether TPM 2.0 chip replied based on
* the reply tag.
*/
int tpm2_probe(struct tpm_chip *chip)
{
struct tpm2_cmd cmd;
int rc;
cmd.header.in = tpm2_get_tpm_pt_header;
cmd.params.get_tpm_pt_in.cap_id = cpu_to_be32(TPM2_CAP_TPM_PROPERTIES);
cmd.params.get_tpm_pt_in.property_id = cpu_to_be32(0x100);
cmd.params.get_tpm_pt_in.property_cnt = cpu_to_be32(1);
rc = tpm_transmit(chip, (const char *) &cmd, sizeof(cmd));
if (rc < 0)
return rc;
else if (rc < TPM_HEADER_SIZE)
return -EFAULT;
if (be16_to_cpu(cmd.header.out.tag) == TPM2_ST_NO_SESSIONS)
chip->flags |= TPM_CHIP_FLAG_TPM2;
return 0;
}
EXPORT_SYMBOL_GPL(tpm2_probe);
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