drivers/char/tpm/tpm-sysfs.c

/*
 * Copyright (C) 2004 IBM Corporation
 * Authors:
 * Leendert van Doorn <leendert@watson.ibm.com>
 * Dave Safford <safford@watson.ibm.com>
 * Reiner Sailer <sailer@watson.ibm.com>
 * Kylene Hall <kjhall@us.ibm.com>
 *
 * Copyright (C) 2013 Obsidian Research Corp
 * Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
 *
 * sysfs filesystem inspection interface to the TPM
 *
 * 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 <linux/device.h>
#include "tpm.h"

#define READ_PUBEK_RESULT_SIZE 314
#define TPM_ORD_READPUBEK cpu_to_be32(124)
static struct tpm_input_header tpm_readpubek_header = {
	.tag = TPM_TAG_RQU_COMMAND,
	.length = cpu_to_be32(30),
	.ordinal = TPM_ORD_READPUBEK
};
static ssize_t pubek_show(struct device *dev, struct device_attribute *attr,
			  char *buf)
{
	u8 *data;
	struct tpm_cmd_t tpm_cmd;
	ssize_t err;
	int i, rc;
	char *str = buf;

	struct tpm_chip *chip = dev_get_drvdata(dev);

	memset(&tpm_cmd, 0, sizeof(tpm_cmd));

	tpm_cmd.header.in = tpm_readpubek_header;
	err = tpm_transmit_cmd(chip, &tpm_cmd, READ_PUBEK_RESULT_SIZE, 0,
			       "attempting to read the PUBEK");
	if (err)
		goto out;

	/*
	   ignore header 10 bytes
	   algorithm 32 bits (1 == RSA )
	   encscheme 16 bits
	   sigscheme 16 bits
	   parameters (RSA 12->bytes: keybit, #primes, expbit)
	   keylenbytes 32 bits
	   256 byte modulus
	   ignore checksum 20 bytes
	 */
	data = tpm_cmd.params.readpubek_out_buffer;
	str +=
	    sprintf(str,
		    "Algorithm: %02X %02X %02X %02X\n"
		    "Encscheme: %02X %02X\n"
		    "Sigscheme: %02X %02X\n"
		    "Parameters: %02X %02X %02X %02X "
		    "%02X %02X %02X %02X "
		    "%02X %02X %02X %02X\n"
		    "Modulus length: %d\n"
		    "Modulus:\n",
		    data[0], data[1], data[2], data[3],
		    data[4], data[5],
		    data[6], data[7],
		    data[12], data[13], data[14], data[15],
		    data[16], data[17], data[18], data[19],
		    data[20], data[21], data[22], data[23],
		    be32_to_cpu(*((__be32 *) (data + 24))));

	for (i = 0; i < 256; i++) {
		str += sprintf(str, "%02X ", data[i + 28]);
		if ((i + 1) % 16 == 0)
			str += sprintf(str, "\n");
	}
out:
	rc = str - buf;
	return rc;
}
static DEVICE_ATTR_RO(pubek);

static ssize_t pcrs_show(struct device *dev, struct device_attribute *attr,
			 char *buf)
{
	cap_t cap;
	u8 digest[TPM_DIGEST_SIZE];
	ssize_t rc;
	int i, j, num_pcrs;
	char *str = buf;
	struct tpm_chip *chip = dev_get_drvdata(dev);

	rc = tpm_getcap(dev, TPM_CAP_PROP_PCR, &cap,
			"attempting to determine the number of PCRS");
	if (rc)
		return 0;

	num_pcrs = be32_to_cpu(cap.num_pcrs);
	for (i = 0; i < num_pcrs; i++) {
		rc = tpm_pcr_read_dev(chip, i, digest);
		if (rc)
			break;
		str += sprintf(str, "PCR-%02d: ", i);
		for (j = 0; j < TPM_DIGEST_SIZE; j++)
			str += sprintf(str, "%02X ", digest[j]);
		str += sprintf(str, "\n");
	}
	return str - buf;
}
static DEVICE_ATTR_RO(pcrs);

static ssize_t enabled_show(struct device *dev, struct device_attribute *attr,
		     char *buf)
{
	cap_t cap;
	ssize_t rc;

	rc = tpm_getcap(dev, TPM_CAP_FLAG_PERM, &cap,
			 "attempting to determine the permanent enabled state");
	if (rc)
		return 0;

	rc = sprintf(buf, "%d\n", !cap.perm_flags.disable);
	return rc;
}
static DEVICE_ATTR_RO(enabled);

static ssize_t active_show(struct device *dev, struct device_attribute *attr,
		    char *buf)
{
	cap_t cap;
	ssize_t rc;

	rc = tpm_getcap(dev, TPM_CAP_FLAG_PERM, &cap,
			 "attempting to determine the permanent active state");
	if (rc)
		return 0;

	rc = sprintf(buf, "%d\n", !cap.perm_flags.deactivated);
	return rc;
}
static DEVICE_ATTR_RO(active);

static ssize_t owned_show(struct device *dev, struct device_attribute *attr,
			  char *buf)
{
	cap_t cap;
	ssize_t rc;

	rc = tpm_getcap(dev, TPM_CAP_PROP_OWNER, &cap,
			 "attempting to determine the owner state");
	if (rc)
		return 0;

	rc = sprintf(buf, "%d\n", cap.owned);
	return rc;
}
static DEVICE_ATTR_RO(owned);

static ssize_t temp_deactivated_show(struct device *dev,
				     struct device_attribute *attr, char *buf)
{
	cap_t cap;
	ssize_t rc;

	rc = tpm_getcap(dev, TPM_CAP_FLAG_VOL, &cap,
			 "attempting to determine the temporary state");
	if (rc)
		return 0;

	rc = sprintf(buf, "%d\n", cap.stclear_flags.deactivated);
	return rc;
}
static DEVICE_ATTR_RO(temp_deactivated);

static ssize_t caps_show(struct device *dev, struct device_attribute *attr,
			 char *buf)
{
	cap_t cap;
	ssize_t rc;
	char *str = buf;

	rc = tpm_getcap(dev, TPM_CAP_PROP_MANUFACTURER, &cap,
			"attempting to determine the manufacturer");
	if (rc)
		return 0;
	str += sprintf(str, "Manufacturer: 0x%x\n",
		       be32_to_cpu(cap.manufacturer_id));

	/* Try to get a TPM version 1.2 TPM_CAP_VERSION_INFO */
	rc = tpm_getcap(dev, CAP_VERSION_1_2, &cap,
			 "attempting to determine the 1.2 version");
	if (!rc) {
		str += sprintf(str,
			       "TCG version: %d.%d\nFirmware version: %d.%d\n",
			       cap.tpm_version_1_2.Major,
			       cap.tpm_version_1_2.Minor,
			       cap.tpm_version_1_2.revMajor,
			       cap.tpm_version_1_2.revMinor);
	} else {
		/* Otherwise just use TPM_STRUCT_VER */
		rc = tpm_getcap(dev, CAP_VERSION_1_1, &cap,
				"attempting to determine the 1.1 version");
		if (rc)
			return 0;
		str += sprintf(str,
			       "TCG version: %d.%d\nFirmware version: %d.%d\n",
			       cap.tpm_version.Major,
			       cap.tpm_version.Minor,
			       cap.tpm_version.revMajor,
			       cap.tpm_version.revMinor);
	}

	return str - buf;
}
static DEVICE_ATTR_RO(caps);

static ssize_t cancel_store(struct device *dev, struct device_attribute *attr,
			    const char *buf, size_t count)
{
	struct tpm_chip *chip = dev_get_drvdata(dev);
	if (chip == NULL)
		return 0;

	chip->ops->cancel(chip);
	return count;
}
static DEVICE_ATTR_WO(cancel);

static ssize_t durations_show(struct device *dev, struct device_attribute *attr,
			      char *buf)
{
	struct tpm_chip *chip = dev_get_drvdata(dev);

	if (chip->vendor.duration[TPM_LONG] == 0)
		return 0;

	return sprintf(buf, "%d %d %d [%s]\n",
		       jiffies_to_usecs(chip->vendor.duration[TPM_SHORT]),
		       jiffies_to_usecs(chip->vendor.duration[TPM_MEDIUM]),
		       jiffies_to_usecs(chip->vendor.duration[TPM_LONG]),
		       chip->vendor.duration_adjusted
		       ? "adjusted" : "original");
}
static DEVICE_ATTR_RO(durations);

static ssize_t timeouts_show(struct device *dev, struct device_attribute *attr,
			     char *buf)
{
	struct tpm_chip *chip = dev_get_drvdata(dev);

	return sprintf(buf, "%d %d %d %d [%s]\n",
		       jiffies_to_usecs(chip->vendor.timeout_a),
		       jiffies_to_usecs(chip->vendor.timeout_b),
		       jiffies_to_usecs(chip->vendor.timeout_c),
		       jiffies_to_usecs(chip->vendor.timeout_d),
		       chip->vendor.timeout_adjusted
		       ? "adjusted" : "original");
}
static DEVICE_ATTR_RO(timeouts);

static struct attribute *tpm_dev_attrs[] = {
	&dev_attr_pubek.attr,
	&dev_attr_pcrs.attr,
	&dev_attr_enabled.attr,
	&dev_attr_active.attr,
	&dev_attr_owned.attr,
	&dev_attr_temp_deactivated.attr,
	&dev_attr_caps.attr,
	&dev_attr_cancel.attr,
	&dev_attr_durations.attr,
	&dev_attr_timeouts.attr,
	NULL,
};

static const struct attribute_group tpm_dev_group = {
	.attrs = tpm_dev_attrs,
};

int tpm_sysfs_add_device(struct tpm_chip *chip)
{
	int err;

	/* XXX: If you wish to remove this restriction, you must first update
	 * tpm_sysfs to explicitly lock chip->ops.
	 */
	if (chip->flags & TPM_CHIP_FLAG_TPM2)
		return 0;

	err = sysfs_create_group(&chip->dev.parent->kobj,
				 &tpm_dev_group);

	if (err)
		dev_err(&chip->dev,
			"failed to create sysfs attributes, %d\n", err);
	return err;
}

void tpm_sysfs_del_device(struct tpm_chip *chip)
{
	/* The sysfs routines rely on an implicit tpm_try_get_ops, this
	 * function is called before ops is null'd and the sysfs core
	 * synchronizes this removal so that no callbacks are running or can
	 * run again
	 */
	sysfs_remove_group(&chip->dev.parent->kobj, &tpm_dev_group);
}